CA2327558C - Ozone generator - Google Patents
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- CA2327558C CA2327558C CA002327558A CA2327558A CA2327558C CA 2327558 C CA2327558 C CA 2327558C CA 002327558 A CA002327558 A CA 002327558A CA 2327558 A CA2327558 A CA 2327558A CA 2327558 C CA2327558 C CA 2327558C
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Abstract
A generator is taught which uses alternating current or pulsating direct current to produce ozone from oxygen. The generator comprises a high voltage (212) and ground electrode (210) separated to form a gap (18) for accommodating a dielectric member (214) and gas to be reacted.
The generator includes many features which may be used alone or in combination to provide an energy efficient and safe apparatus.
The generator includes many features which may be used alone or in combination to provide an energy efficient and safe apparatus.
Description
OZONE GENERATOR
FIELD OF THE INVENTION:
This invention is directed to an apparatus for producing ozone and, in particular, an apparatus for producing ozone using alternating current or pulsating direct io current.
Background of the Invention Ozone generators are known which employ corona j5 discharge to produce ozone from oxygen by action or oxygen atoms or. oxygen molecules. These generators employ a high voltage alternating sinusoidal current operating at frequencies of between about 60 and 5,000 Hz and voltages frequently above 20 kilovolts. Such generators require high zo voltage transformers which are difficult to construct and insulate and which cause the generatcr to be very large i.~.
size.
During breakdown, oxygen or air in the gap becomes 25 partially ionized as several kilovolts of energy i=_ applied to it, and milliampere to ampere currents result. Because c' the required operating frequencies and voltages of most known generators and the fragile nature of the dielectrics of the reaction chamber, deterioration. o. the generators often 30 occurs, requiring maintenance arid repair. The construction of known generators requires that the entire unit including generator, transforme-- anc any associated electronics be shipped offsite for repair and maintenance.
la To allow a better understanding of the prior art, reference may be made to the following drawings of prior art in which Figures 1 and 2, each show a prior art ozone generator.
s Referring to Figure 1, a plate generator i0 is shown having a pair of metallic plate electrodes 12, 14 and a layer of dielectric material 20 therebetween. Electrodes 12, 14 are separated to form a gap 18.
io The ozone generator of Figure 2 employs a tubular geometry and includes a first electrode 25 and a second, larger diameter, eieccrode 26. Electrode 25 has a layer of dielectric~material 27 disposed on the surface thereof and is is positioned within electrode 26 to form a gap 28 therebetween.
In known generators, such as those shown in Figures 1 and 2, a high voltage current is applied to the electrodes to produce a corona discharge in the gap. The discharge zu produces ozone by ionization of oxygen which is presen~ in the gap.
FIELD OF THE INVENTION:
This invention is directed to an apparatus for producing ozone and, in particular, an apparatus for producing ozone using alternating current or pulsating direct io current.
Background of the Invention Ozone generators are known which employ corona j5 discharge to produce ozone from oxygen by action or oxygen atoms or. oxygen molecules. These generators employ a high voltage alternating sinusoidal current operating at frequencies of between about 60 and 5,000 Hz and voltages frequently above 20 kilovolts. Such generators require high zo voltage transformers which are difficult to construct and insulate and which cause the generatcr to be very large i.~.
size.
During breakdown, oxygen or air in the gap becomes 25 partially ionized as several kilovolts of energy i=_ applied to it, and milliampere to ampere currents result. Because c' the required operating frequencies and voltages of most known generators and the fragile nature of the dielectrics of the reaction chamber, deterioration. o. the generators often 30 occurs, requiring maintenance arid repair. The construction of known generators requires that the entire unit including generator, transforme-- anc any associated electronics be shipped offsite for repair and maintenance.
la To allow a better understanding of the prior art, reference may be made to the following drawings of prior art in which Figures 1 and 2, each show a prior art ozone generator.
s Referring to Figure 1, a plate generator i0 is shown having a pair of metallic plate electrodes 12, 14 and a layer of dielectric material 20 therebetween. Electrodes 12, 14 are separated to form a gap 18.
io The ozone generator of Figure 2 employs a tubular geometry and includes a first electrode 25 and a second, larger diameter, eieccrode 26. Electrode 25 has a layer of dielectric~material 27 disposed on the surface thereof and is is positioned within electrode 26 to form a gap 28 therebetween.
In known generators, such as those shown in Figures 1 and 2, a high voltage current is applied to the electrodes to produce a corona discharge in the gap. The discharge zu produces ozone by ionization of oxygen which is presen~ in the gap.
Summar~of the Invention It is an object of the present invention to provide an ozone generator. In accordance with an aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, and a dielectric element occupying a portion of the gap, the generator element being electrically connected to a circuit for producing an alternating current or pulsed direct current by means of a releasable connector, said high voltage electrode extending into a spacer, and said releasable connector connecting the high voltage electrode through said spacer to said 1 p circuit.
In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, end a dielectric element occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, and a grounded current collector at an outlet to the generator element.
In accordance with another aspect of the invention there is provided an ozone generator system comprising: a plurality of generator elements, each generator element having a high voltage electrode, a ground electrode separated from the high-voltage electrode to form a 2p gap therebetween and a dielectric element occupying a portion of the gap;
and, a circuit for producing alternating or pulsating direct current electrically connected to the high voltage electrode of each generator element, fiuther comprising a valve at the outlet of each generator, each valve being an electrical valve and in series with the circuit; and, a current-sensitive protection device in communication with the circuit and valves for interrupting the current to the circuit and the valves when the current exceeds a predetermined value.
2a In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, and a dielectric element occupying a portion of the gap, the generator S element being electrically connected to a circuit for producing an alternating current or pulsed direct current by means of a releasable connector, and a grounded current collector at an outlet from the generator element, wherein the dielectric member is a tubular member, accommodated within and in contact with the ground electrode, and the high voltage electrode is disposed within the dielectric member.
In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, and a dielectric element occupying a portion of the gap, the generator element being electrically connected to a circuit for producing an alternating current or 1 S pulsed direct current by means of a releasable connector, wherein the dielectric member is a tubular member, accommodated within and in contact with the ground electrode and the high voltage electrode is disposed within the dielectric member, the generator element further comprises an end cap at each end thereof, each end cap is formed as a block having a chamber for passage of gas therethrough, each said block having an aperture for insertion of the dielectric member therein such that a continuous passage is formed between the end blocks, and further comprising a grounded current collector at an outlet from the generator element.
According to a broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric eleme:~.t disposed therebetween and occupying a portion of the gap, the generator element being electrically connected to a circwi= v for producing an alternating current or pulsed direct current ' and the generator element being removable from the circuit.
2b According to a further broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the s high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, the high voltage and ground electrodes being ~o impedance matched to the circuit.
According to a further broad aspect of the present invention there is provided an apparatus for producing czone from oxygen comprising a generator element having a high ~s voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion. of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct zo current, and a grounded current collector at an output of the generator element.
According to a further broad aspect of the present invention there is provided an apparatus for producing ozone z5 from oxygen comprising a generator element havinc a high voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a 30 _circuit for producing alternating or pulsating direct current, the chamber being provided such that its =nductance and capacitance are selected to produce a waveform ~.-=thin the gap having a high frequency component which is selected break the oxygen - oxygen bond.
According to a further broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the s high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, the circuit having a saturable transformer with at io least one feedback winding.
Description of the Invention A generator is provided whic~: employs alternating is current or pulsating direct curre~:t to produce ozone from oxygen gas or oxygen-containing gas. The generator comprises a generator element comprising a ground electrode and a high voltage electrode spaced from the ground electrode and having a discharge gap therebetween to accommodate the gas and a zn dielectric member. In a preferred e~~odiment, the gererato~Y
element is of a tubular arrangement ~~~:herein the high voltage electrode is disposed within the around electrode and the dielectric layer is disposed therebetween. The aenerato=
element is formed to contain a gas any perm=t flow of the zs gas, where desired, through the dischargelgap.
The ground electrode __ formed o. suitable conductive metal or semi-conductive material. Where the aas flow is passed in contact with the electrode, the around ~u electrode is made from a material, such as for example, stainless stee-'_, which is ozone iner-~. In an embodiment of a tubular generator arrangement, the ground electrode is formed as a tube into which the dielectric and high voltage electrode fit. In another embodiment, the ground electrode 3s is formed as a block and provides support fer the dielectric.
The block electrode is formed with a channel therethrough e=
in sections having alignable grooves for accommodating the dielectric.
The high voltage electrode is formed of materials s similar to those of the ground electrode and is evenly spaced from the ground electrode to provide an even capacitive load.
In a generator element having a tubular geometry the high voltage electrode is formed to fit within the ground electrode and a discharge gap is formed therebetween. To ~o provide an even capacitive load in the generator, the high voltage electrode is maintained substantially centrally within the ground electrode by any suitable means. In an embodiment, the high voltage electrode is a wire held centrally by means of centraiizer spirals formed of a:. inert is polymer. Alternatively, dielectric centering blocks, such as ceramic triangles or apertured discs, can be employed. In an alternate embodiment, a spiral electrode is provided and is maintained centrally by means of centering blocks disDOSed at each end of the channel in which the electrode is mounted.
2o In such an embodiment, a dielectric member can be used as a support for the spiral electrode by winding the electrode about the member or by inserting the member into a prepared spiral electrode. The member is solid and acts to prevent the flow of gas -along the center aris of the chamber and ?s thereby directs the gas through electrical discharge between the high voltage and the ground electrodes. In another embodiment the centering blocks are formed integral ;Kith the dielectric support member and the spiral electrode is wound thereabout.
The dielectric member which is positioned between the ground electrode and the high voltage electrode acts as capacitor together with the gas which is supplied to the generator. In one embodiment, the d-lelectric is positionec:
3s in close contact with the ground electrode. Alternativel=, the dielectric material is disposed about t:~e hig_-_ voltage electrode. The dielectric member is formed of a suitable dielectric material such as a ceramic, glass or polymeric material and is preferably separate or easily separable from the electrodes to allow for independent replacement of the s dielectric member apart from the electrodes and to facilitate recycling of generator components. In a preferred embodiment, the dielectric member is formed of mullite ceramic.
io The generator is formed to contain gas in any suitable way. In embodiments with a tubular geometry, the gas passes between the tubular electrodes and ' is contained therebetween by a pair of end caps. The end caps provide ports for electrical contact and input and output o~ gas. In n an embodiment, the end caps are formed as en~7 h~r,rk-~ T~r supporting the generator element and containing means for electrical connection and flow paths for the gas. The end blocks can be formed to prevent direct access to the ~:~ner components. The end blocks are formed of an ozor_e inert zo dielectric.
Contact must be provided between the electrodes and the generator circuit for producing the current for o=one generation. Preferably:, such contact is releasable such that zs when desired, the generator element of the present inve_-__ior.
can be removed fror;, the generator fcr maintenance and repair.
In an embodiment, a high voltage plug connection is employed.
A plug is mounted on th=_ generator element and in communication with the high voltage electrode which is 3u disposed to make contact with a socket provided i:_ communication with the externa_ circuit. In a oreT=_rred embodiment, the high voltage electrode is connected to the circuitry by means c~ a high voltage pin. The pin has a first end which extends =rom the generator to form a plot and ~s a second end for contacting the high voltage electrode. Suc:-_ contact can be a pressure contact made in the acerture _= a centering block into which the second end of the pin and an end of the high voltage electrode are each inserted. Such a contact arrangement avoids the need for soldering.
The electrode geometry in the generator can be selected to create impedance in the generator circuit which matches the impedance of the circuitry. In a plate generator arrangement, the distance between the electrodes, the surface area of the electrodes and the density of the electrodes, ~o such as for example, the use of mesh electrodes or solid electrodes, can be selected to allow for impedance matching.
Impedance matching in a tubular generator can be accomplished by selecting the pitch and length of a spiral high voltage electrode or by winding a selected number of turns of a ~s conductive wire ir_ contact wit: t:~e high voltage or ground electrodes. Such impedance matching enhances the energy efficiency of the generator.
To dissipate the heat produced in the generator, it 2o is desirable to provide a heat sink arrangement in association with the generator element. The heat sing: can preferably also be an electrical around for the generator and, as such, is provided in intimate contact with the ground electrode but is detachable therefrom, when desired.
To prevent a shock hazard by use of the inven~ive generator, should water enter the generator and make contact with the high voltage electrode, a grounded current collector can be provided at the gas outlet to ground the current. In an embodiment, the currer.~ collector is formed as a electrically conductive conduit ~~r carrying output gas and is grounded by contact with the ground electrode of the generator. In another embodiment, the current collector is a conduit formed integral with the ground electrode and i_~.
3s engagement with the end blocks.
All components of the generator which are in contact with the gas must be built having regard to the corrosion problems of the gas to be introduced and the ozone formed in the generator, as is known in the art.
The generator is of use with pulsating direct current or alternating current. In a preferred embodiment, oxygen-oxygen bonds are selectively broken by use of a high frequency, high voltage alternating current or pulsed direct io current discharge which is selected to have a waveform having a fast rise leading edge suitable for breaking the oxygen -oxygen bona. The fast rise portion cf the waveform creates a range of high frequency components defined by the rate of change at each point on the slope ir_ conjunction with the i5 repetition. rate and the amplitude of the waveform. The time that the leading edge of a wavefor:n is maintained at any given frequency combined with the voltage at that point give a potential energy transfer rate.
2ca ~o break the oxygen-oxygen bonds the leading edge of the waveform is selected tc nave a high frequency comDOnent which breaks the oxygen molecules apart, termed the "active frequency" or "active high frequency component".
This active Frequency must be.appiied at a suitable voltage zs and be maintained for a sufficient time to transfer enoug~~
energy to the molecule to breal~; the bond.
it is believed that the active high frequency component is close to a primary cr harmonic of the natural zo oscillating frequency of the oxygen-oxygen bond and therefore creates constructive interference w.,ith the oscillation of any oxygen-oxygen bonds which are ~_. phase with the applied active freauency. It is believed that suitable active freQUencies are at least i~ the megahertz range. This active frequency is applied at a suitable voltage and is maintained for a sufficient time to trans=e= enougenergy t~ the ;;
molecule to break the bond. It is believed that the suitable voltage is at least 3 times the combined strength of the bonds to be broken. It is further believed that an avalanche effect is created wherein further oxygen-oxygen bonds are s broken by those broken through the application of the active frequency. In such an effect, the release of bond energy causes the separated oxygen atoms to be high in energy and to collide with other oxygen molecules that are weakened from the application of the current. Due to the collision, the ~o oxygen-oxygen bonds of the weakened molecules are broken.
Since it is believed that the applied active freauency can be a harmonic of the natural oscillating frequency, it is also believed that there are many active frequencies that are suitable for interference with the. oxygen.-oxygen bond, as is there are many harmonics of that bond.
In an ozone generator employing a current having an active high frequency component, it is believed that substantially only oxygen - oxygen bonds are broken, even zo where other molecular species are present. However, due to ionization in the chamber and the impact c. high energy oxygen atoms, some side reactions may occur suc~ as the production of nitrous oxides.
25 In an emi~odiment, a periodic wave for-. is generated having a leading edge selected to represeT~ a:: active frequency for breaking oxygen - oxygen bonds and sufficient voltage to break the bond once it is applied. In a continuous system, wherein oxygen molecule= are being :~o converted to ozone and passed on, the fiov:~ rat. c' the molecules through the chamber must be consi.er~d and the . voltage should be increased accordingly, to expose each portion of the gas containing the oxygen ;molecules to sufficient voltage Lo initiate bond breakage bef~:~re the gas ~s passes out of the generator.
In order to carry out the process of the bresent invention, the generator circuitry is set to apply an alternating or pulsed direct current having a fast rise and sufficient voltage. To obtain an active high frequency s component and optimize the waveform for ozone production, the repetition rate of the waveform or amplitude of the current, or inductance or capacitance of the circuit, transformer or generator can be adjusted while analyzing ozone production by use of a chemical analyzer, such as a mass spectrometer or to ozone monitor. In a preferred embodiment, the inductance and capacitance are maintained constant, while the repetition rate and amplitude are adjusted to obtain an active high frequency component. Once the generator is set, the ozone production can continue without modification at substantially is similar operating pressure and temperature. Ar_y changes in the voltage or the repetition rate of the applied discharge or changes in the inductance or capacitance of the circuit, generator or transformer, including changes in pressure or generator load, require recptimization of the waveform to zo re-establish the active high frequency component. Such readjustment can be made manuall;r or by use of a circuit feedback arrangement. In addition, in generators produced with similar geometr~~, the circuit can be optimized once and incorporated into eat:: further generator without resetting.
Iri One embodiment c CaTJaCitlVe-induCtl.Ve reSOnati.nQ
circuit is used to produce a carrier waveform raving the required active frequency for the ozone production. The circuit is powered by any suitable power supply or source.
3o The resultant waveform can be an alternating current o= a pulsed direc t curre_~_. having a f as t rise leading edge . I:. a preferred embodiment, the curren~ is a pulsating direct current having a_-_ active frequency component ant is preferably generates a~d maintained, by an electronic circui=
ss employing a saturable trans=ormer having a feedback winding.
The his =reauency~ cor"ponen t is produced b-.~ " swi tc::ing o~ "
transistor until the core of the transformer is magnetically saturated, as determined by the feedback winding or windings and the connected generator. The "switch on" initiates oscillation at the circuit resonance frequency and once s initiated the energy from the core of the transformer maintains the reaction. In an alternate preferred embodiment, the current is a high voltage direct current having the active frequency component added thereto.
to In the preferred embodiment, the generator acts as the capacitance in a parallel resonant circuit with the secondary winding of the transformer forming the inductor.
The capacitive and inductive characteristics of the generator cell and inductor are chosen such that the circuit is is essentiall;~~ resistive at the resonant, active frequency.
Energy transfer to the gas produces some heat and causes ozone production by interfering with and breaking the oxygen - oxygen bond.
2o Since the presence oT gas alters the capacitance of the resonant circuit, the electronic circuit o-_' the present invention is capable of compensating for chances in the reactor loading such as the gas fiov:: rate, gas density, gas composition or gas temperature by sensing the changes in the 2s dielectric constant of the gas. Any changes in the dielectric constant o. the gas cause_-- the c~.~rrent of the discharge in the generator to change, and hence the feedback winding changes the operating repetition rate to maintain. the required active frequency for ozone production.
F flowing stream of gas ca:: pe fed to the generator such that a continuous process for ozone production. is set up. To increase the output of ozone by the generator, the length o~ the generator element ca.~_ be extended or a 3s plurality of generator elements can be provided in series or parallel. In such arrangements, an e~~ectricai control can be provided to detect malfunction: and cause the'generator to be shut down.
Brief Description of the Drawingrs s A further, detailed, description of the invention, briefly described above, will follow by reference to the following drawings of specific embodiments of the invention, which depict only typical embodiments of the invention and io are therefore not to be considered limiting of its scope. In the drawincrs Figure 1 shows a prior art ozone generator;
is Figure 2 shows another prior art ozone generator;
Figure 3 shows a sectional view along the axis of an embodiment of a generator element according to the present invention;
zo Figure 4 shows an exploded, perspective view of another embodiment of a generator according to the present invention;
Figure 5 shows a sectional vie:: through an end bloc:: of zs an embodiment of a generator according to the present invention;
Figure 6 shows a perspective view of a modular generator according to the present invention with a panel of the ~a housing removed to sho~:: the inner components;
Figure t shows a schematic diagram of a generator system according to the present invention;
3s Figure 8 shows an oscilloscope representation of a waveform useful i.~. the prese_-.= inve_-_~tior.;
Figure 9 shows a circuit diagram of an electronic circuit useful in the present invention; and, Figures l0A and lOB show oscilloscope representations of s waveforms useful in the present invention.
Detailed Description of the Invention Referring to Figure 3, a perspective view of a ~o generator element according to the present invention is shown comprising an outer grade electrode 210, an inner high voltage electrode 212 and a dielectric member 214 therebetween. Ground electrode 210 is formed as a ~~PPVP
which is in telescopic arrangement with dielectric member 214 n but is removable therefrom. High voltage electrode 212 is a straight length of metal such as stainless steel and is held concentrically within the dielectric member 214 by means of spiral centralizers 216 formed of plastic. End caps 218 are provided at the ends of the element tc seal against the ~o passage of gas out of the bore of the dielectric member 214.
Ports 22C, 221 are formed in end caps 2".~c for mountinc gas supply and output lines 222, 223, respectively. Electrical connectors 224 are mounted on end caps 218 for connectic.~. to electrical lines 225.
~5 Gas containing oxygen flows into ti:e generato~-through port 22C and passes through the bore of dielectric member 214. Alternating current or pulsating direct current is applied between electrodes 210 and 213, by contact with ar_ :~o external power source through connectors 224 and lines 225, and through the gas causing ionization and modificatio_~. of the molecular species present in the gas. Gas containinc ozone moves out of the generator through the exit port 221.
A conductive iaye= 228 is provided about the inner surface of ~s es:=~~ port 221 which is in contact with ground electrode 21C
via wire 229 and thereby provides fer collection of current if water passes through it into contact with electrode 212.
When replacement or repair of the generator s components is required, the generator is shut down, such as by stopping supply of gas and power and removing the supply lines. The end caps are removed and the defective parts are removed, including possibly the entire generator element. A
new generator element can then be connected and the ~o generation process re-initiated.
Referring to Figure 4, a preferred generator for ozone production i= shown. The generator comprises ar.
apparatus 23 for producing a current comprising a waveform is having ar. active frequency componen " a reaction chamber 24 and a heat sink arrangement 26 associated with apparatus 23 and reaction chamber 24.
Reaction chamber 24 comprises ground electrodes 33 2o and 34 having corresponding groove= formed t~erei~ fer accommodating and contacting die 1 ectric tubu'~a= me.."ber 3c .
Electrodes 3, 34 are secured about member 36 by- poi riveis 38 and 40.
zs Disposed ~~:ithin member ~.. is high voltage spiral electrode 4= consisting of ozone inert meta_ su.... as stainless steel. The pitch and length of electrode 42 is selected to impedance match the impedance o= apparatus ''3.
In addition, the -~ength of electrode 4~ is selected to 3o prevent node reflection at the reauired dischara=_ wave=orr~;.
A screw 43. forme:i of a suitable dieiectr~_c material ,1s inserted through a t~readed aperture 4~ in end block ~:; to be in engagemer:t wit: an end 52 of electrode 42 whicallows externa~~. adjustme-t of the length and pitch of electrode 4..
ss A dielectri_ member 4z acts as a Filler and support =cr Splra! eleC.'_rOQe 4L . An enC DOr tlOr~ =.. G. SDlra_ __e'troQ°_ ~a 42 is inserted into central aperture 48 of centering triangle 50. The other end 52 of spiral electrode 42 is inserted into central aperture 54 of centering block 56. Tubular dielectric member 36 containing spiral electrode 42 and s associated parts 44, 50, 56 is inserted between apertures 66, 68 of end blocks 58 and 60, formed of suitable dielectric material, respectively. Sealing means, such as 0-rings 62, 64 are provided to seal the connection between tubular member 36 and the end blocks against passage of gas. Other sealing io means can be used such as, for example, silicone sealant. A
high voltage pin 70 is inserted into aperture 48 of centering block 50 to be in electrical communication with end 46 of spiral electrode 42. The other end of pin 70 extends through, and is engaged within, an aperture 71 in end block i5 58 for electrical communication with apparatus 23.
A current collector 72 formed as a tubular member from corrosion resistant conductive metal is sealably secured such.as by press fitting at its ends into apertures 74 and 76 20 of ends blocks 58 and 60, respectively. Current collector acts mechanically to join and form a gas conduit between end blocks 58 and 60. Electrodes 33 and 34 accommodate and make contact with c~,:rrent collector 72. Since electrodes _~ and 34 are at grcund potential durinc operation and are =r.
2s intimate contact u:ith current collector 72, current collector 72 serves to prevent electrical c~.~rrent from passing our of the generator element during use.
Referrinc to Figures 4 and ~, a stream c_ gas 3o containing a. least a portion of oxygen is provided to the generator throug~ entry nozzle 78 into an upper chamber 7? c.
block 6G. Unner chamber 79 of the block 60 is former generally a= ar_ "L "shaped chamber having an extending portion 79a whir: impedes insertio:: of articles, sucas ss wires, into the generator to contact high voltage elec=rode 42 . Stil 1 refers ing to Figur a 3 , screw 4 is inserted ...,._ aperture 45 to be in contact with electrode 42. Electrode 42 is maintained in a recess formed in an end of screw 43 and is held therein by the resiliency in electrode 42. The length of electrode 42 can be altered by changing the extent to s which screw 43 is inserted into end block 60.
The gas is directed into and passes through dielectric tubular member 36 and about spiral electrode 42 into end block 58. Dielectric member 44 acts within io dielectric member 36 to dire~t the gas into close association with spiral electrode 42. The spiral configuration, in addition to providing impedance ir. the generator, acts to create turbulence in the passinc gas stream and thereby enhance mixing. Such mixing al-~.ows for increases heat o transfer from electrode 42 to electrodes 33 and 34 which are cooled by heat sink 26. Gas returns along the bore of current collector 72 to enter a loc~:er chamber 73 of block 60 where an outlet 77 is provided from the generator. Gas passing through this system is reacted when passing through zo dielectric tubular member 36 preferably by application of a selected active frequency current applied through electrode 42. Current is pro~~ided to eiectrcce 42 by apparatus 23.
Apparatus 23 for producing current is of any suitable kind. I~. a preferred eT.bodiment, apparatus 23 is comprised of a circuit, as wild be described in reference to Figure 9, including among its components a high voltage transformer 80, a low voltage t=ansformer 82, a bridge rectifier 86, a sc,;itch 109, tra~:sister 90 and associated ~o electronics 88. Th--__ low voltage transformer 82 is provides with fluctuating ~oower such as a-_ternating current by means of plug 84. Th= current produced b-_r apparatus 23 is communicated to the generator through a high voltage wire 96 having a plug socket 98 on an end t.~.ereof for making contact ;s with high voltage pin 7G in e=.~ block 58. Switch 109 interrupts t:~~e power =lowing =ro:-, t::e transformer 82 to the W
electronics 88 when end block 58 is moved away from plug 98.
Thermal switch 112 on heat sink 26 interrupts power flowing from transformer 82 when the temperature in the generator exceeds a predetermined level.
s When the high frequency, high voltage current is applied to the gas in the generator, heat is generated. A
heat sink 26 is provided in association with reaction chamber 24 to reduce temperature fluctuations in the generator. Heat ~o sink 26 comprises a thermally conductive tube 121 which is inserted into a heat sink block 122. A suitable ccnlanr ;s circulated through tube 121. Holes in the heat sink block 122 include a threaded hole 123 to mount the transistor 90 and a threaded hole 125 to mount the bridge rectifier 86.
is Heat sink block 122 is firmly mounted to ground electrodes 33 and 34 through conductive screws 126 which also act to ground electrodes 33 and 34. Screws 126 are easily removable to allow removal of generator element.
za Referring to Figure 6, in the preferred embodiment, the generator is provided in the form of a module tc facilitate installation. The module comprises a housing 600 (shown with the top removed> formed of durable material such as thermoplastic. Housing 600 provides encasement for an zs apparatus 623 for producing current, a generator element 624 and a heat sink arrangement 626. E~a ending from housing 600, for connection to external supply lines, are plug 684 and ends 621a and 621b of thermally conductive tube 621.
Additionally, end block 660 of generator element 624 extends so from housing 600 to allow connection of gas lines to entry nozzle 678 and outlet 677. Generator element 624 is removably ir_stalled within housing 600 by insertior_ through aperture 697 and into abutment with upstanding stop 699 (generator element 624 is shown partially inserted in Figure ,i 6?. Stop 69°, formed of a suitab_e dielectric, supports high voltage plug socket 698 which is a'~igned for contact wit: a high voltage pin extending through an aperture of end block 658. When in place screws 6126 are inserted through a side wall of housing 600 to engage heat sink 626 and the ground electrodes of generator element 624. A pressure sensitive s switch 6109, disposed adjacent stop 699, interrupts the power to apparatus 623, when generator element 624 is not fully inserted into housing 600 such that the high voltage pin is not inserted into socket 698. Such a generator element installation arrangement allows for removal and replacement ~o of chambers, when desired, without affecting the circuitry or heat sink components.
As shown schematically in Figure ", the cutput of ozone by the present ozone generator can be increased by is providing a generator system comprising a plurality of generator elements 724a, 724b and 724c in series. Problems in scale-up, such as reconfiguration of enlarged generators, are thus avoided by installing optimized generators in greater numbers. To control the passage of untreated gas ~o through the system, in case of system fa,_lure, valves 799a, 799b and 799c are provided at the cutlet cf each generator element so that gas can flow from element 724c through element 724b and then through element 724a. These valves are held open in no-rural operation by power supplied via line 797, ~s which is in~_ series with the apparatus 723 for producing current. Where th=_ system fails, suc~. as bv.- dielectric breakdown, a current-sensitive protective device 79~, such as a fuse or circuit breaker, in the power supply 793 senses the increase in current and stops power to the system. Valves 30 799a, 799b, and 799c then stop the flow of gas through the chambers 724x, 724b and 724c unti-_ the flow c. current is resumed, thereby preventing output ef anw unreacted gas through the system.
Referring to Figure 8, a waveform is shown which is useful in the selective breaking of oxygen-oxygen bonds in oxygen molecules to produce ozone. The active portion of the waveform is shown between A and B. From the oscilloscope, s calculations of the slope of the substantially straight rise portion of the leading edge between A and B indicate that the rate of voltage increase over this portion is in the order of 6.6 x 10 volts/second. Such an active portion is believed to correspond to a frequency in the order of 10 to 100 io megaHz. The waveform is applied at a repetition rate of about 6.67 kHz to air at a temperature of 26'C and atmospheric pressure to produce ozone. Ozone generation is enhanced by applying the waveform to air at lower temperatures. The generator of use.;:ith the waveform having ~s parameters as shown is generally as shown in Figure 4 and is 4 to 8 inches in length having a corresponding length high voltage electrode having 22 turns and formed from .036 inch stainless steel wire.
zo Referring to Figure 9, a preferred embodiment o. a circuit is shown. for use in generating curren~ comprising a waveform as shown in Figure 8. The circuit comprises a Darlington pair transistor T1 and a ferrite core transformer TR1. The transformer TR'_ has four windings, the primary 2s winding 30G, a secondary (output! winding 31G, and twa feedback windings 32G and 330. The primar_.~ winding 300 connects the collector of the traiaistor Tl to the positive power supply voltage. The secor_dar~.~ winding 31G is the output of the generator circuit and is applied to one of the :~o electrodes of the reactor cell shown. in Figure ~. The feedbag: winding 320 is connected via diode D~ and R3 to the base of the transistor T1.. The other terminal a. the feedback winding 320 is connected to the biasing circuit o. the transistor T'~, which comprises variable resistor V?.1, 3s resistor R. and resistor R2, as well as silicon sc~.itchina diodes D1, Dl and D3. The ieedbac:~ winding 33'.,' connects the emitter of the transistor T1 to the negative terminal of the power supply. The circuit operates as follows.
Transistor T1 is present to permit the generation s of a fast rise waveform. In a circuit which is intended to produce pulsed DC waveforms, one transistor T1 is used. If it is desired to produce AC waveforms, a second transistor (not shown) is used. As the transistor T1 is handling a high peak current, a heat sink to dissipate the heat generated by ~o such current should be used.
Transformer TR1 is a saturabie transformer having a ferrite core material with very io4: losses. In a preferred embodiment, TR1 has a ferrite core comprising a 7 turn a primar;.~ winding 300, a 3 turn feedback winding 320, a 1 turn feedback winding 330 and a secondary winding 310 having 3300 turns of 22 gauge wire.
The diodes D1, D2, D3, and D4 are silicon s~~:itching zo diodes that are selected to have voltage and temperature characteristics ~,~riich correspond the Darlington Transistcr.
Diodes D1, D2, and D3 give a regulated "switch on" voltage for transistor T1. Diode D4 acts to prevent the negative feedback voltage turning the base-emitter junction c~
~a transistor T1 back "on" by reverse voltage avalanche breakdow:~. Any similar silicon switc:zing diode to IN914 ca_~.
be used for diodes D1, D2, D3, and D4.
Variable resistor VF.= and fixed resistor _..
3o regulate the curre.~= to maintain the voltage across the diodes and bias tre base of the transistor T1. 'variable resistor VF.1 is used to set the operating current, compensating for different gain of transistors. Resistor F__ acts to limit the current when variable resistor VR'_ is set :~s to 0. Alternatively, a fixed value resister o= suitable ?u resistance for the transistor used, can replace both R1 and VR1.
Feedback winding 330 is connected to the emitter of s the transistor. It provides compensation for change of gain versus temperature, and provides some compensation for transistors of different gain. Winding 330 is most useful in high power reactors. However, since it also acts to damp harmonics in the system, which would interfere with the to desired active frequency, it is preferably included in all circuits.
Capacitor C1 reduces variations __. the supply ' voltage reaching the base of transistor T1 during normal is operation. This is important in high current aenerators.
Due to the high switching current, smoothing capacitors Cl and C2 much each handle high peak ripple currents and must be rated accordingly.
'o Power is applied to the circuit by ar. r.C source, as shown. The current within the circuit is preferably I? t,rol=
DC. Therefore where I20 volt power is used a step dow-transformer is required prior to the bridge rectifier BP.'_.
The bridge rectifier is useful even where the power suppl~_~ _s ?s a battery, since the rectification allows connec~ion of t:ne battery without concern as to matching terminals.
After power is applied to the circuit, the base e.
transistor T1 ,_s driven positive and the collector curre_~..
3o increases. For the purposes of this description, == __ assumed that the circuit has been operating for some time ar_~
that we are starting the description from the point where the base of transistor '~" is being driver_ pcsitiv~ and th=
collector current is increasina.
_i With transistor T1 fully switched on, the current through the primary winding of TR1 transformer increases at a rate set by the transformer inductance and the generator capacitance. As the current increases, the transformer core s magnetizes, and a voltage is induced into the base feedback winding 320. The negative going end of feedback winding 320 is connected to the voltage reference diodes D1, D2, D3 and the positive going end connected through diode D4 to resistor R2 and the base of transistor T1. Thus, an induced voltage ~o in feedback winding 320 acts to maintain transistor T1 "on".
The actual drive current is set by the value of the resistors VR1 and R1.
Resistor R3 together ~~~.th the base input ~s capacitance of transistor Tl reduces current oscillation at very high frequency during switching. Preferably, resistor R3 is connected directly at the base of transistor T1.
As the transformer core approaches saturaticrl, the zo rate of current increase drops. As _~ drops, the induced voltage in the base feedback winding reduces thus reducing the drive to the transistor which then starts to turn of~.
This reduces the rate o~ increase of the collector curren:.
through primary winding 300 and thi= in turn fur'her and ?5 further reduces the feedback voicage. This very rapidi-~.~
turns the transistor fully of.. As t~°_ core magnetic field is no longer being maintained by the transistor, the magnetic field collapses reversing the voltage in the base feedbaci=
winding 320 and placing a negative voltage on the anode o.
3u -diode Da turning it o_= thus keepinc transistor T~~ Lurned off. This also effectively unloads the feedback winding 32C
and prevents any damping of the noc~; oscillating secondar;
winding 310.
As the current drops towards zero across the base of feedback winding 320, the generated negative voltage across the back feedback winding 320 decreases until it no longer cancels the bias voltage at the cathode of diode D1.
s When this happens, the transistor starts to turn on. As it does, the current starts increasing and this in turn reverses the voltage in the base feedback winding 320. This applies additional positive voltage to the base of transistor T1 turning it fully on and into full saturation. Now the io transistor is turned fully on and the collector current increases, which is where the cycle repeats.
The invention will be further illustrated by the following examples. While the examples illustrate the is invention, they are not intended to limit its scope.
Example 1 Air at atmospheric pressure and 26'C was 2o dehumidified such that it had a de~~~ point between 35° and 40'F. The air was introduced t_ an ozone generator, generally as described in reference tc Figure 4, at a fiov.°
rate of 31/min. Air exiting the generator was passed to ar_ ozone monitor for analvsis.
Electrical discharges were applied to the air as follows 1. ~: sinusoidal waveform having a frequency of 60 Yz and so varied between 5,000 and 8,000 volts;
2. A sinusoidal waveform having a Trequency of 6.5 kH= and ranging between 5,000 and 8,000 volts;
ss 3. i: square waveform having a =requency of 6.5 kLz and ranging between 5,000 and 8,000 volts; or, 4. A waveform according to Figure 8 at a repetition rate of 6.67 kHz and an amplitude of 4,500 volts.
Typical ozone production results by use of s waveforms 1 to 4 for treatment of air are summarized in Table 1.
Table 1 io Waveform Ozone Concentration by weight) 1 0.001 2 0.066 ~s 3 0 . 066 4 0.332 Conversion rates were increased by use of the fast rise waveform according to the presen~ inventive process.
zo Example 2 Air at atmospheric pressure and 22'C and having a relative humidity of 80~ was introduced at a flow rate of 3.~
zs 1/min to ozone generators, generally ~as described in reference to Figure S without the use of a heat sink and having the parameters as set out in Tap'~e 2.
Table 2 Ozone generator A Ozone generator B
s Length 12 inch 4 inch Capacitance 147 pF 34 pF
(at frequency=0) Resonance 58.2 Mhz 66.0 Mhz Inductance 0.0508 uH 0.170 uH
~o The measurements for the generators were carried out in 18'C, atmospheric pressure and 70~RH using a MIC 37 multimeter and a MFJ HF/VHF SWR analyze., to measure capacitance and resonance,. respectively. Inductance was calculated.
l5 The waveform was monitored using a Phillips PM3365A
100MHz Oscilloscope set at 5 VDC and .lms connected to a Techtronix P6015 1000x probe. Air exiting the generator was passed to an ozone monitor for analysis.
The waveforms which were found to produce optimum amounts of ozone for generator A and generator B are shown in Figures l0A and 108, respectively. The waveform parameters and ozone production results are shown in Table 3.
,;
Table 3 Ozone generator Ozone generator A B
Repetition rate (Hz) 1603 1637 Voltage (kV) 20 22 Leading edge rate of voltage increase (V/s)* 234 x 106 233.5 x 106 to Ozone concentration (~ by weight) 0.190 0.145 * determined from oscilloscope is The active frequency for ozone production is uniform for gas having the same composition, flow rate, temperature and pressure regardless, of the reactor parameters. The active frequency can be determined for each zo reactor by adjusting the amplitude and repetition rate.
Examt~le 3 Air .at atmospheric pressure and 22'C and having a zs relative humidity of 80~ was introduced at a =low rate of 3.8 1/min to ozone generator A as described in Example 2. The waveform was monitored using a Phi'ylips PM3365A i00M~-iz Oscilloscope set at 5 VDC and .lms connected to a Techtroni~:
P6015 1000x probe. Air exiting the generator was passed to 3o an ozone monitor for analysis.
The waveform was changed from waveform 1, having a slower rate of voltage increase than the waveform oL Figure 10A, to waveform 2, according to Figure 10A, by adjusting the 3s power to the generator. Results are shosrm in Table 4.
Table 4 Waveform Ozone Concentration ( % by v'eiQht ) s 1 0.021 2 0.190 It will be apparent that many other changes may be ~o made to the illustrative embodiments, while falling within the scope of the invention and it is intended that all such changes be covered by the claims appended hereto.
~s
In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, end a dielectric element occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, and a grounded current collector at an outlet to the generator element.
In accordance with another aspect of the invention there is provided an ozone generator system comprising: a plurality of generator elements, each generator element having a high voltage electrode, a ground electrode separated from the high-voltage electrode to form a 2p gap therebetween and a dielectric element occupying a portion of the gap;
and, a circuit for producing alternating or pulsating direct current electrically connected to the high voltage electrode of each generator element, fiuther comprising a valve at the outlet of each generator, each valve being an electrical valve and in series with the circuit; and, a current-sensitive protection device in communication with the circuit and valves for interrupting the current to the circuit and the valves when the current exceeds a predetermined value.
2a In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, and a dielectric element occupying a portion of the gap, the generator S element being electrically connected to a circuit for producing an alternating current or pulsed direct current by means of a releasable connector, and a grounded current collector at an outlet from the generator element, wherein the dielectric member is a tubular member, accommodated within and in contact with the ground electrode, and the high voltage electrode is disposed within the dielectric member.
In accordance with another aspect of the invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode, a ground electrode separated from the high voltage electrode to form a gap therebetween, and a dielectric element occupying a portion of the gap, the generator element being electrically connected to a circuit for producing an alternating current or 1 S pulsed direct current by means of a releasable connector, wherein the dielectric member is a tubular member, accommodated within and in contact with the ground electrode and the high voltage electrode is disposed within the dielectric member, the generator element further comprises an end cap at each end thereof, each end cap is formed as a block having a chamber for passage of gas therethrough, each said block having an aperture for insertion of the dielectric member therein such that a continuous passage is formed between the end blocks, and further comprising a grounded current collector at an outlet from the generator element.
According to a broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric eleme:~.t disposed therebetween and occupying a portion of the gap, the generator element being electrically connected to a circwi= v for producing an alternating current or pulsed direct current ' and the generator element being removable from the circuit.
2b According to a further broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the s high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, the high voltage and ground electrodes being ~o impedance matched to the circuit.
According to a further broad aspect of the present invention there is provided an apparatus for producing czone from oxygen comprising a generator element having a high ~s voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion. of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct zo current, and a grounded current collector at an output of the generator element.
According to a further broad aspect of the present invention there is provided an apparatus for producing ozone z5 from oxygen comprising a generator element havinc a high voltage electrode and a ground electrode separated from the high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a 30 _circuit for producing alternating or pulsating direct current, the chamber being provided such that its =nductance and capacitance are selected to produce a waveform ~.-=thin the gap having a high frequency component which is selected break the oxygen - oxygen bond.
According to a further broad aspect of the present invention there is provided an apparatus for producing ozone from oxygen comprising a generator element having a high voltage electrode and a ground electrode separated from the s high voltage electrode to form a gap and a dielectric element disposed therebetween and occupying a portion of the gap, the high voltage electrode being electrically connected to a circuit for producing alternating or pulsating direct current, the circuit having a saturable transformer with at io least one feedback winding.
Description of the Invention A generator is provided whic~: employs alternating is current or pulsating direct curre~:t to produce ozone from oxygen gas or oxygen-containing gas. The generator comprises a generator element comprising a ground electrode and a high voltage electrode spaced from the ground electrode and having a discharge gap therebetween to accommodate the gas and a zn dielectric member. In a preferred e~~odiment, the gererato~Y
element is of a tubular arrangement ~~~:herein the high voltage electrode is disposed within the around electrode and the dielectric layer is disposed therebetween. The aenerato=
element is formed to contain a gas any perm=t flow of the zs gas, where desired, through the dischargelgap.
The ground electrode __ formed o. suitable conductive metal or semi-conductive material. Where the aas flow is passed in contact with the electrode, the around ~u electrode is made from a material, such as for example, stainless stee-'_, which is ozone iner-~. In an embodiment of a tubular generator arrangement, the ground electrode is formed as a tube into which the dielectric and high voltage electrode fit. In another embodiment, the ground electrode 3s is formed as a block and provides support fer the dielectric.
The block electrode is formed with a channel therethrough e=
in sections having alignable grooves for accommodating the dielectric.
The high voltage electrode is formed of materials s similar to those of the ground electrode and is evenly spaced from the ground electrode to provide an even capacitive load.
In a generator element having a tubular geometry the high voltage electrode is formed to fit within the ground electrode and a discharge gap is formed therebetween. To ~o provide an even capacitive load in the generator, the high voltage electrode is maintained substantially centrally within the ground electrode by any suitable means. In an embodiment, the high voltage electrode is a wire held centrally by means of centraiizer spirals formed of a:. inert is polymer. Alternatively, dielectric centering blocks, such as ceramic triangles or apertured discs, can be employed. In an alternate embodiment, a spiral electrode is provided and is maintained centrally by means of centering blocks disDOSed at each end of the channel in which the electrode is mounted.
2o In such an embodiment, a dielectric member can be used as a support for the spiral electrode by winding the electrode about the member or by inserting the member into a prepared spiral electrode. The member is solid and acts to prevent the flow of gas -along the center aris of the chamber and ?s thereby directs the gas through electrical discharge between the high voltage and the ground electrodes. In another embodiment the centering blocks are formed integral ;Kith the dielectric support member and the spiral electrode is wound thereabout.
The dielectric member which is positioned between the ground electrode and the high voltage electrode acts as capacitor together with the gas which is supplied to the generator. In one embodiment, the d-lelectric is positionec:
3s in close contact with the ground electrode. Alternativel=, the dielectric material is disposed about t:~e hig_-_ voltage electrode. The dielectric member is formed of a suitable dielectric material such as a ceramic, glass or polymeric material and is preferably separate or easily separable from the electrodes to allow for independent replacement of the s dielectric member apart from the electrodes and to facilitate recycling of generator components. In a preferred embodiment, the dielectric member is formed of mullite ceramic.
io The generator is formed to contain gas in any suitable way. In embodiments with a tubular geometry, the gas passes between the tubular electrodes and ' is contained therebetween by a pair of end caps. The end caps provide ports for electrical contact and input and output o~ gas. In n an embodiment, the end caps are formed as en~7 h~r,rk-~ T~r supporting the generator element and containing means for electrical connection and flow paths for the gas. The end blocks can be formed to prevent direct access to the ~:~ner components. The end blocks are formed of an ozor_e inert zo dielectric.
Contact must be provided between the electrodes and the generator circuit for producing the current for o=one generation. Preferably:, such contact is releasable such that zs when desired, the generator element of the present inve_-__ior.
can be removed fror;, the generator fcr maintenance and repair.
In an embodiment, a high voltage plug connection is employed.
A plug is mounted on th=_ generator element and in communication with the high voltage electrode which is 3u disposed to make contact with a socket provided i:_ communication with the externa_ circuit. In a oreT=_rred embodiment, the high voltage electrode is connected to the circuitry by means c~ a high voltage pin. The pin has a first end which extends =rom the generator to form a plot and ~s a second end for contacting the high voltage electrode. Suc:-_ contact can be a pressure contact made in the acerture _= a centering block into which the second end of the pin and an end of the high voltage electrode are each inserted. Such a contact arrangement avoids the need for soldering.
The electrode geometry in the generator can be selected to create impedance in the generator circuit which matches the impedance of the circuitry. In a plate generator arrangement, the distance between the electrodes, the surface area of the electrodes and the density of the electrodes, ~o such as for example, the use of mesh electrodes or solid electrodes, can be selected to allow for impedance matching.
Impedance matching in a tubular generator can be accomplished by selecting the pitch and length of a spiral high voltage electrode or by winding a selected number of turns of a ~s conductive wire ir_ contact wit: t:~e high voltage or ground electrodes. Such impedance matching enhances the energy efficiency of the generator.
To dissipate the heat produced in the generator, it 2o is desirable to provide a heat sink arrangement in association with the generator element. The heat sing: can preferably also be an electrical around for the generator and, as such, is provided in intimate contact with the ground electrode but is detachable therefrom, when desired.
To prevent a shock hazard by use of the inven~ive generator, should water enter the generator and make contact with the high voltage electrode, a grounded current collector can be provided at the gas outlet to ground the current. In an embodiment, the currer.~ collector is formed as a electrically conductive conduit ~~r carrying output gas and is grounded by contact with the ground electrode of the generator. In another embodiment, the current collector is a conduit formed integral with the ground electrode and i_~.
3s engagement with the end blocks.
All components of the generator which are in contact with the gas must be built having regard to the corrosion problems of the gas to be introduced and the ozone formed in the generator, as is known in the art.
The generator is of use with pulsating direct current or alternating current. In a preferred embodiment, oxygen-oxygen bonds are selectively broken by use of a high frequency, high voltage alternating current or pulsed direct io current discharge which is selected to have a waveform having a fast rise leading edge suitable for breaking the oxygen -oxygen bona. The fast rise portion cf the waveform creates a range of high frequency components defined by the rate of change at each point on the slope ir_ conjunction with the i5 repetition. rate and the amplitude of the waveform. The time that the leading edge of a wavefor:n is maintained at any given frequency combined with the voltage at that point give a potential energy transfer rate.
2ca ~o break the oxygen-oxygen bonds the leading edge of the waveform is selected tc nave a high frequency comDOnent which breaks the oxygen molecules apart, termed the "active frequency" or "active high frequency component".
This active Frequency must be.appiied at a suitable voltage zs and be maintained for a sufficient time to transfer enoug~~
energy to the molecule to breal~; the bond.
it is believed that the active high frequency component is close to a primary cr harmonic of the natural zo oscillating frequency of the oxygen-oxygen bond and therefore creates constructive interference w.,ith the oscillation of any oxygen-oxygen bonds which are ~_. phase with the applied active freauency. It is believed that suitable active freQUencies are at least i~ the megahertz range. This active frequency is applied at a suitable voltage and is maintained for a sufficient time to trans=e= enougenergy t~ the ;;
molecule to break the bond. It is believed that the suitable voltage is at least 3 times the combined strength of the bonds to be broken. It is further believed that an avalanche effect is created wherein further oxygen-oxygen bonds are s broken by those broken through the application of the active frequency. In such an effect, the release of bond energy causes the separated oxygen atoms to be high in energy and to collide with other oxygen molecules that are weakened from the application of the current. Due to the collision, the ~o oxygen-oxygen bonds of the weakened molecules are broken.
Since it is believed that the applied active freauency can be a harmonic of the natural oscillating frequency, it is also believed that there are many active frequencies that are suitable for interference with the. oxygen.-oxygen bond, as is there are many harmonics of that bond.
In an ozone generator employing a current having an active high frequency component, it is believed that substantially only oxygen - oxygen bonds are broken, even zo where other molecular species are present. However, due to ionization in the chamber and the impact c. high energy oxygen atoms, some side reactions may occur suc~ as the production of nitrous oxides.
25 In an emi~odiment, a periodic wave for-. is generated having a leading edge selected to represeT~ a:: active frequency for breaking oxygen - oxygen bonds and sufficient voltage to break the bond once it is applied. In a continuous system, wherein oxygen molecule= are being :~o converted to ozone and passed on, the fiov:~ rat. c' the molecules through the chamber must be consi.er~d and the . voltage should be increased accordingly, to expose each portion of the gas containing the oxygen ;molecules to sufficient voltage Lo initiate bond breakage bef~:~re the gas ~s passes out of the generator.
In order to carry out the process of the bresent invention, the generator circuitry is set to apply an alternating or pulsed direct current having a fast rise and sufficient voltage. To obtain an active high frequency s component and optimize the waveform for ozone production, the repetition rate of the waveform or amplitude of the current, or inductance or capacitance of the circuit, transformer or generator can be adjusted while analyzing ozone production by use of a chemical analyzer, such as a mass spectrometer or to ozone monitor. In a preferred embodiment, the inductance and capacitance are maintained constant, while the repetition rate and amplitude are adjusted to obtain an active high frequency component. Once the generator is set, the ozone production can continue without modification at substantially is similar operating pressure and temperature. Ar_y changes in the voltage or the repetition rate of the applied discharge or changes in the inductance or capacitance of the circuit, generator or transformer, including changes in pressure or generator load, require recptimization of the waveform to zo re-establish the active high frequency component. Such readjustment can be made manuall;r or by use of a circuit feedback arrangement. In addition, in generators produced with similar geometr~~, the circuit can be optimized once and incorporated into eat:: further generator without resetting.
Iri One embodiment c CaTJaCitlVe-induCtl.Ve reSOnati.nQ
circuit is used to produce a carrier waveform raving the required active frequency for the ozone production. The circuit is powered by any suitable power supply or source.
3o The resultant waveform can be an alternating current o= a pulsed direc t curre_~_. having a f as t rise leading edge . I:. a preferred embodiment, the curren~ is a pulsating direct current having a_-_ active frequency component ant is preferably generates a~d maintained, by an electronic circui=
ss employing a saturable trans=ormer having a feedback winding.
The his =reauency~ cor"ponen t is produced b-.~ " swi tc::ing o~ "
transistor until the core of the transformer is magnetically saturated, as determined by the feedback winding or windings and the connected generator. The "switch on" initiates oscillation at the circuit resonance frequency and once s initiated the energy from the core of the transformer maintains the reaction. In an alternate preferred embodiment, the current is a high voltage direct current having the active frequency component added thereto.
to In the preferred embodiment, the generator acts as the capacitance in a parallel resonant circuit with the secondary winding of the transformer forming the inductor.
The capacitive and inductive characteristics of the generator cell and inductor are chosen such that the circuit is is essentiall;~~ resistive at the resonant, active frequency.
Energy transfer to the gas produces some heat and causes ozone production by interfering with and breaking the oxygen - oxygen bond.
2o Since the presence oT gas alters the capacitance of the resonant circuit, the electronic circuit o-_' the present invention is capable of compensating for chances in the reactor loading such as the gas fiov:: rate, gas density, gas composition or gas temperature by sensing the changes in the 2s dielectric constant of the gas. Any changes in the dielectric constant o. the gas cause_-- the c~.~rrent of the discharge in the generator to change, and hence the feedback winding changes the operating repetition rate to maintain. the required active frequency for ozone production.
F flowing stream of gas ca:: pe fed to the generator such that a continuous process for ozone production. is set up. To increase the output of ozone by the generator, the length o~ the generator element ca.~_ be extended or a 3s plurality of generator elements can be provided in series or parallel. In such arrangements, an e~~ectricai control can be provided to detect malfunction: and cause the'generator to be shut down.
Brief Description of the Drawingrs s A further, detailed, description of the invention, briefly described above, will follow by reference to the following drawings of specific embodiments of the invention, which depict only typical embodiments of the invention and io are therefore not to be considered limiting of its scope. In the drawincrs Figure 1 shows a prior art ozone generator;
is Figure 2 shows another prior art ozone generator;
Figure 3 shows a sectional view along the axis of an embodiment of a generator element according to the present invention;
zo Figure 4 shows an exploded, perspective view of another embodiment of a generator according to the present invention;
Figure 5 shows a sectional vie:: through an end bloc:: of zs an embodiment of a generator according to the present invention;
Figure 6 shows a perspective view of a modular generator according to the present invention with a panel of the ~a housing removed to sho~:: the inner components;
Figure t shows a schematic diagram of a generator system according to the present invention;
3s Figure 8 shows an oscilloscope representation of a waveform useful i.~. the prese_-.= inve_-_~tior.;
Figure 9 shows a circuit diagram of an electronic circuit useful in the present invention; and, Figures l0A and lOB show oscilloscope representations of s waveforms useful in the present invention.
Detailed Description of the Invention Referring to Figure 3, a perspective view of a ~o generator element according to the present invention is shown comprising an outer grade electrode 210, an inner high voltage electrode 212 and a dielectric member 214 therebetween. Ground electrode 210 is formed as a ~~PPVP
which is in telescopic arrangement with dielectric member 214 n but is removable therefrom. High voltage electrode 212 is a straight length of metal such as stainless steel and is held concentrically within the dielectric member 214 by means of spiral centralizers 216 formed of plastic. End caps 218 are provided at the ends of the element tc seal against the ~o passage of gas out of the bore of the dielectric member 214.
Ports 22C, 221 are formed in end caps 2".~c for mountinc gas supply and output lines 222, 223, respectively. Electrical connectors 224 are mounted on end caps 218 for connectic.~. to electrical lines 225.
~5 Gas containing oxygen flows into ti:e generato~-through port 22C and passes through the bore of dielectric member 214. Alternating current or pulsating direct current is applied between electrodes 210 and 213, by contact with ar_ :~o external power source through connectors 224 and lines 225, and through the gas causing ionization and modificatio_~. of the molecular species present in the gas. Gas containinc ozone moves out of the generator through the exit port 221.
A conductive iaye= 228 is provided about the inner surface of ~s es:=~~ port 221 which is in contact with ground electrode 21C
via wire 229 and thereby provides fer collection of current if water passes through it into contact with electrode 212.
When replacement or repair of the generator s components is required, the generator is shut down, such as by stopping supply of gas and power and removing the supply lines. The end caps are removed and the defective parts are removed, including possibly the entire generator element. A
new generator element can then be connected and the ~o generation process re-initiated.
Referring to Figure 4, a preferred generator for ozone production i= shown. The generator comprises ar.
apparatus 23 for producing a current comprising a waveform is having ar. active frequency componen " a reaction chamber 24 and a heat sink arrangement 26 associated with apparatus 23 and reaction chamber 24.
Reaction chamber 24 comprises ground electrodes 33 2o and 34 having corresponding groove= formed t~erei~ fer accommodating and contacting die 1 ectric tubu'~a= me.."ber 3c .
Electrodes 3, 34 are secured about member 36 by- poi riveis 38 and 40.
zs Disposed ~~:ithin member ~.. is high voltage spiral electrode 4= consisting of ozone inert meta_ su.... as stainless steel. The pitch and length of electrode 42 is selected to impedance match the impedance o= apparatus ''3.
In addition, the -~ength of electrode 4~ is selected to 3o prevent node reflection at the reauired dischara=_ wave=orr~;.
A screw 43. forme:i of a suitable dieiectr~_c material ,1s inserted through a t~readed aperture 4~ in end block ~:; to be in engagemer:t wit: an end 52 of electrode 42 whicallows externa~~. adjustme-t of the length and pitch of electrode 4..
ss A dielectri_ member 4z acts as a Filler and support =cr Splra! eleC.'_rOQe 4L . An enC DOr tlOr~ =.. G. SDlra_ __e'troQ°_ ~a 42 is inserted into central aperture 48 of centering triangle 50. The other end 52 of spiral electrode 42 is inserted into central aperture 54 of centering block 56. Tubular dielectric member 36 containing spiral electrode 42 and s associated parts 44, 50, 56 is inserted between apertures 66, 68 of end blocks 58 and 60, formed of suitable dielectric material, respectively. Sealing means, such as 0-rings 62, 64 are provided to seal the connection between tubular member 36 and the end blocks against passage of gas. Other sealing io means can be used such as, for example, silicone sealant. A
high voltage pin 70 is inserted into aperture 48 of centering block 50 to be in electrical communication with end 46 of spiral electrode 42. The other end of pin 70 extends through, and is engaged within, an aperture 71 in end block i5 58 for electrical communication with apparatus 23.
A current collector 72 formed as a tubular member from corrosion resistant conductive metal is sealably secured such.as by press fitting at its ends into apertures 74 and 76 20 of ends blocks 58 and 60, respectively. Current collector acts mechanically to join and form a gas conduit between end blocks 58 and 60. Electrodes 33 and 34 accommodate and make contact with c~,:rrent collector 72. Since electrodes _~ and 34 are at grcund potential durinc operation and are =r.
2s intimate contact u:ith current collector 72, current collector 72 serves to prevent electrical c~.~rrent from passing our of the generator element during use.
Referrinc to Figures 4 and ~, a stream c_ gas 3o containing a. least a portion of oxygen is provided to the generator throug~ entry nozzle 78 into an upper chamber 7? c.
block 6G. Unner chamber 79 of the block 60 is former generally a= ar_ "L "shaped chamber having an extending portion 79a whir: impedes insertio:: of articles, sucas ss wires, into the generator to contact high voltage elec=rode 42 . Stil 1 refers ing to Figur a 3 , screw 4 is inserted ...,._ aperture 45 to be in contact with electrode 42. Electrode 42 is maintained in a recess formed in an end of screw 43 and is held therein by the resiliency in electrode 42. The length of electrode 42 can be altered by changing the extent to s which screw 43 is inserted into end block 60.
The gas is directed into and passes through dielectric tubular member 36 and about spiral electrode 42 into end block 58. Dielectric member 44 acts within io dielectric member 36 to dire~t the gas into close association with spiral electrode 42. The spiral configuration, in addition to providing impedance ir. the generator, acts to create turbulence in the passinc gas stream and thereby enhance mixing. Such mixing al-~.ows for increases heat o transfer from electrode 42 to electrodes 33 and 34 which are cooled by heat sink 26. Gas returns along the bore of current collector 72 to enter a loc~:er chamber 73 of block 60 where an outlet 77 is provided from the generator. Gas passing through this system is reacted when passing through zo dielectric tubular member 36 preferably by application of a selected active frequency current applied through electrode 42. Current is pro~~ided to eiectrcce 42 by apparatus 23.
Apparatus 23 for producing current is of any suitable kind. I~. a preferred eT.bodiment, apparatus 23 is comprised of a circuit, as wild be described in reference to Figure 9, including among its components a high voltage transformer 80, a low voltage t=ansformer 82, a bridge rectifier 86, a sc,;itch 109, tra~:sister 90 and associated ~o electronics 88. Th--__ low voltage transformer 82 is provides with fluctuating ~oower such as a-_ternating current by means of plug 84. Th= current produced b-_r apparatus 23 is communicated to the generator through a high voltage wire 96 having a plug socket 98 on an end t.~.ereof for making contact ;s with high voltage pin 7G in e=.~ block 58. Switch 109 interrupts t:~~e power =lowing =ro:-, t::e transformer 82 to the W
electronics 88 when end block 58 is moved away from plug 98.
Thermal switch 112 on heat sink 26 interrupts power flowing from transformer 82 when the temperature in the generator exceeds a predetermined level.
s When the high frequency, high voltage current is applied to the gas in the generator, heat is generated. A
heat sink 26 is provided in association with reaction chamber 24 to reduce temperature fluctuations in the generator. Heat ~o sink 26 comprises a thermally conductive tube 121 which is inserted into a heat sink block 122. A suitable ccnlanr ;s circulated through tube 121. Holes in the heat sink block 122 include a threaded hole 123 to mount the transistor 90 and a threaded hole 125 to mount the bridge rectifier 86.
is Heat sink block 122 is firmly mounted to ground electrodes 33 and 34 through conductive screws 126 which also act to ground electrodes 33 and 34. Screws 126 are easily removable to allow removal of generator element.
za Referring to Figure 6, in the preferred embodiment, the generator is provided in the form of a module tc facilitate installation. The module comprises a housing 600 (shown with the top removed> formed of durable material such as thermoplastic. Housing 600 provides encasement for an zs apparatus 623 for producing current, a generator element 624 and a heat sink arrangement 626. E~a ending from housing 600, for connection to external supply lines, are plug 684 and ends 621a and 621b of thermally conductive tube 621.
Additionally, end block 660 of generator element 624 extends so from housing 600 to allow connection of gas lines to entry nozzle 678 and outlet 677. Generator element 624 is removably ir_stalled within housing 600 by insertior_ through aperture 697 and into abutment with upstanding stop 699 (generator element 624 is shown partially inserted in Figure ,i 6?. Stop 69°, formed of a suitab_e dielectric, supports high voltage plug socket 698 which is a'~igned for contact wit: a high voltage pin extending through an aperture of end block 658. When in place screws 6126 are inserted through a side wall of housing 600 to engage heat sink 626 and the ground electrodes of generator element 624. A pressure sensitive s switch 6109, disposed adjacent stop 699, interrupts the power to apparatus 623, when generator element 624 is not fully inserted into housing 600 such that the high voltage pin is not inserted into socket 698. Such a generator element installation arrangement allows for removal and replacement ~o of chambers, when desired, without affecting the circuitry or heat sink components.
As shown schematically in Figure ", the cutput of ozone by the present ozone generator can be increased by is providing a generator system comprising a plurality of generator elements 724a, 724b and 724c in series. Problems in scale-up, such as reconfiguration of enlarged generators, are thus avoided by installing optimized generators in greater numbers. To control the passage of untreated gas ~o through the system, in case of system fa,_lure, valves 799a, 799b and 799c are provided at the cutlet cf each generator element so that gas can flow from element 724c through element 724b and then through element 724a. These valves are held open in no-rural operation by power supplied via line 797, ~s which is in~_ series with the apparatus 723 for producing current. Where th=_ system fails, suc~. as bv.- dielectric breakdown, a current-sensitive protective device 79~, such as a fuse or circuit breaker, in the power supply 793 senses the increase in current and stops power to the system. Valves 30 799a, 799b, and 799c then stop the flow of gas through the chambers 724x, 724b and 724c unti-_ the flow c. current is resumed, thereby preventing output ef anw unreacted gas through the system.
Referring to Figure 8, a waveform is shown which is useful in the selective breaking of oxygen-oxygen bonds in oxygen molecules to produce ozone. The active portion of the waveform is shown between A and B. From the oscilloscope, s calculations of the slope of the substantially straight rise portion of the leading edge between A and B indicate that the rate of voltage increase over this portion is in the order of 6.6 x 10 volts/second. Such an active portion is believed to correspond to a frequency in the order of 10 to 100 io megaHz. The waveform is applied at a repetition rate of about 6.67 kHz to air at a temperature of 26'C and atmospheric pressure to produce ozone. Ozone generation is enhanced by applying the waveform to air at lower temperatures. The generator of use.;:ith the waveform having ~s parameters as shown is generally as shown in Figure 4 and is 4 to 8 inches in length having a corresponding length high voltage electrode having 22 turns and formed from .036 inch stainless steel wire.
zo Referring to Figure 9, a preferred embodiment o. a circuit is shown. for use in generating curren~ comprising a waveform as shown in Figure 8. The circuit comprises a Darlington pair transistor T1 and a ferrite core transformer TR1. The transformer TR'_ has four windings, the primary 2s winding 30G, a secondary (output! winding 31G, and twa feedback windings 32G and 330. The primar_.~ winding 300 connects the collector of the traiaistor Tl to the positive power supply voltage. The secor_dar~.~ winding 31G is the output of the generator circuit and is applied to one of the :~o electrodes of the reactor cell shown. in Figure ~. The feedbag: winding 320 is connected via diode D~ and R3 to the base of the transistor T1.. The other terminal a. the feedback winding 320 is connected to the biasing circuit o. the transistor T'~, which comprises variable resistor V?.1, 3s resistor R. and resistor R2, as well as silicon sc~.itchina diodes D1, Dl and D3. The ieedbac:~ winding 33'.,' connects the emitter of the transistor T1 to the negative terminal of the power supply. The circuit operates as follows.
Transistor T1 is present to permit the generation s of a fast rise waveform. In a circuit which is intended to produce pulsed DC waveforms, one transistor T1 is used. If it is desired to produce AC waveforms, a second transistor (not shown) is used. As the transistor T1 is handling a high peak current, a heat sink to dissipate the heat generated by ~o such current should be used.
Transformer TR1 is a saturabie transformer having a ferrite core material with very io4: losses. In a preferred embodiment, TR1 has a ferrite core comprising a 7 turn a primar;.~ winding 300, a 3 turn feedback winding 320, a 1 turn feedback winding 330 and a secondary winding 310 having 3300 turns of 22 gauge wire.
The diodes D1, D2, D3, and D4 are silicon s~~:itching zo diodes that are selected to have voltage and temperature characteristics ~,~riich correspond the Darlington Transistcr.
Diodes D1, D2, and D3 give a regulated "switch on" voltage for transistor T1. Diode D4 acts to prevent the negative feedback voltage turning the base-emitter junction c~
~a transistor T1 back "on" by reverse voltage avalanche breakdow:~. Any similar silicon switc:zing diode to IN914 ca_~.
be used for diodes D1, D2, D3, and D4.
Variable resistor VF.= and fixed resistor _..
3o regulate the curre.~= to maintain the voltage across the diodes and bias tre base of the transistor T1. 'variable resistor VF.1 is used to set the operating current, compensating for different gain of transistors. Resistor F__ acts to limit the current when variable resistor VR'_ is set :~s to 0. Alternatively, a fixed value resister o= suitable ?u resistance for the transistor used, can replace both R1 and VR1.
Feedback winding 330 is connected to the emitter of s the transistor. It provides compensation for change of gain versus temperature, and provides some compensation for transistors of different gain. Winding 330 is most useful in high power reactors. However, since it also acts to damp harmonics in the system, which would interfere with the to desired active frequency, it is preferably included in all circuits.
Capacitor C1 reduces variations __. the supply ' voltage reaching the base of transistor T1 during normal is operation. This is important in high current aenerators.
Due to the high switching current, smoothing capacitors Cl and C2 much each handle high peak ripple currents and must be rated accordingly.
'o Power is applied to the circuit by ar. r.C source, as shown. The current within the circuit is preferably I? t,rol=
DC. Therefore where I20 volt power is used a step dow-transformer is required prior to the bridge rectifier BP.'_.
The bridge rectifier is useful even where the power suppl~_~ _s ?s a battery, since the rectification allows connec~ion of t:ne battery without concern as to matching terminals.
After power is applied to the circuit, the base e.
transistor T1 ,_s driven positive and the collector curre_~..
3o increases. For the purposes of this description, == __ assumed that the circuit has been operating for some time ar_~
that we are starting the description from the point where the base of transistor '~" is being driver_ pcsitiv~ and th=
collector current is increasina.
_i With transistor T1 fully switched on, the current through the primary winding of TR1 transformer increases at a rate set by the transformer inductance and the generator capacitance. As the current increases, the transformer core s magnetizes, and a voltage is induced into the base feedback winding 320. The negative going end of feedback winding 320 is connected to the voltage reference diodes D1, D2, D3 and the positive going end connected through diode D4 to resistor R2 and the base of transistor T1. Thus, an induced voltage ~o in feedback winding 320 acts to maintain transistor T1 "on".
The actual drive current is set by the value of the resistors VR1 and R1.
Resistor R3 together ~~~.th the base input ~s capacitance of transistor Tl reduces current oscillation at very high frequency during switching. Preferably, resistor R3 is connected directly at the base of transistor T1.
As the transformer core approaches saturaticrl, the zo rate of current increase drops. As _~ drops, the induced voltage in the base feedback winding reduces thus reducing the drive to the transistor which then starts to turn of~.
This reduces the rate o~ increase of the collector curren:.
through primary winding 300 and thi= in turn fur'her and ?5 further reduces the feedback voicage. This very rapidi-~.~
turns the transistor fully of.. As t~°_ core magnetic field is no longer being maintained by the transistor, the magnetic field collapses reversing the voltage in the base feedbaci=
winding 320 and placing a negative voltage on the anode o.
3u -diode Da turning it o_= thus keepinc transistor T~~ Lurned off. This also effectively unloads the feedback winding 32C
and prevents any damping of the noc~; oscillating secondar;
winding 310.
As the current drops towards zero across the base of feedback winding 320, the generated negative voltage across the back feedback winding 320 decreases until it no longer cancels the bias voltage at the cathode of diode D1.
s When this happens, the transistor starts to turn on. As it does, the current starts increasing and this in turn reverses the voltage in the base feedback winding 320. This applies additional positive voltage to the base of transistor T1 turning it fully on and into full saturation. Now the io transistor is turned fully on and the collector current increases, which is where the cycle repeats.
The invention will be further illustrated by the following examples. While the examples illustrate the is invention, they are not intended to limit its scope.
Example 1 Air at atmospheric pressure and 26'C was 2o dehumidified such that it had a de~~~ point between 35° and 40'F. The air was introduced t_ an ozone generator, generally as described in reference tc Figure 4, at a fiov.°
rate of 31/min. Air exiting the generator was passed to ar_ ozone monitor for analvsis.
Electrical discharges were applied to the air as follows 1. ~: sinusoidal waveform having a frequency of 60 Yz and so varied between 5,000 and 8,000 volts;
2. A sinusoidal waveform having a Trequency of 6.5 kH= and ranging between 5,000 and 8,000 volts;
ss 3. i: square waveform having a =requency of 6.5 kLz and ranging between 5,000 and 8,000 volts; or, 4. A waveform according to Figure 8 at a repetition rate of 6.67 kHz and an amplitude of 4,500 volts.
Typical ozone production results by use of s waveforms 1 to 4 for treatment of air are summarized in Table 1.
Table 1 io Waveform Ozone Concentration by weight) 1 0.001 2 0.066 ~s 3 0 . 066 4 0.332 Conversion rates were increased by use of the fast rise waveform according to the presen~ inventive process.
zo Example 2 Air at atmospheric pressure and 22'C and having a relative humidity of 80~ was introduced at a flow rate of 3.~
zs 1/min to ozone generators, generally ~as described in reference to Figure S without the use of a heat sink and having the parameters as set out in Tap'~e 2.
Table 2 Ozone generator A Ozone generator B
s Length 12 inch 4 inch Capacitance 147 pF 34 pF
(at frequency=0) Resonance 58.2 Mhz 66.0 Mhz Inductance 0.0508 uH 0.170 uH
~o The measurements for the generators were carried out in 18'C, atmospheric pressure and 70~RH using a MIC 37 multimeter and a MFJ HF/VHF SWR analyze., to measure capacitance and resonance,. respectively. Inductance was calculated.
l5 The waveform was monitored using a Phillips PM3365A
100MHz Oscilloscope set at 5 VDC and .lms connected to a Techtronix P6015 1000x probe. Air exiting the generator was passed to an ozone monitor for analysis.
The waveforms which were found to produce optimum amounts of ozone for generator A and generator B are shown in Figures l0A and 108, respectively. The waveform parameters and ozone production results are shown in Table 3.
,;
Table 3 Ozone generator Ozone generator A B
Repetition rate (Hz) 1603 1637 Voltage (kV) 20 22 Leading edge rate of voltage increase (V/s)* 234 x 106 233.5 x 106 to Ozone concentration (~ by weight) 0.190 0.145 * determined from oscilloscope is The active frequency for ozone production is uniform for gas having the same composition, flow rate, temperature and pressure regardless, of the reactor parameters. The active frequency can be determined for each zo reactor by adjusting the amplitude and repetition rate.
Examt~le 3 Air .at atmospheric pressure and 22'C and having a zs relative humidity of 80~ was introduced at a =low rate of 3.8 1/min to ozone generator A as described in Example 2. The waveform was monitored using a Phi'ylips PM3365A i00M~-iz Oscilloscope set at 5 VDC and .lms connected to a Techtroni~:
P6015 1000x probe. Air exiting the generator was passed to 3o an ozone monitor for analysis.
The waveform was changed from waveform 1, having a slower rate of voltage increase than the waveform oL Figure 10A, to waveform 2, according to Figure 10A, by adjusting the 3s power to the generator. Results are shosrm in Table 4.
Table 4 Waveform Ozone Concentration ( % by v'eiQht ) s 1 0.021 2 0.190 It will be apparent that many other changes may be ~o made to the illustrative embodiments, while falling within the scope of the invention and it is intended that all such changes be covered by the claims appended hereto.
~s
Claims (38)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. ~A method for producing ozone comprising:
(a) introducing oxygen having an oxygen-oxygen bond to a discharge gap;
(b) applying a periodic waveform having a fast rise leading edge and having a suitable voltage to at least partially ionize the oxygen in the discharge gap to selectively break the oxygen-oxygen bond and produce ionized oxygen whereupon at least a portion of the ionized oxygen recombines to produce ozone; and (c) withdrawing ozone from the discharge gap.
(a) introducing oxygen having an oxygen-oxygen bond to a discharge gap;
(b) applying a periodic waveform having a fast rise leading edge and having a suitable voltage to at least partially ionize the oxygen in the discharge gap to selectively break the oxygen-oxygen bond and produce ionized oxygen whereupon at least a portion of the ionized oxygen recombines to produce ozone; and (c) withdrawing ozone from the discharge gap.
2. The method as claimed in claim 1, further comprising:
producing the fast rising leading edge to include a portion having a constant slope.
producing the fast rising leading edge to include a portion having a constant slope.
3. The method as claimed in claim 1, further comprising:
producing the periodic waveform to include a slow falling trailing edge.
producing the periodic waveform to include a slow falling trailing edge.
4. The method as claimed in claim 1, further comprising:
producing the periodic waveform using a generator having an inductive component.
producing the periodic waveform using a generator having an inductive component.
5. The method as claimed in claim 1, comprising:
producing the periodic waveform using a generator having a capacitive-inductive resonating circuit.
producing the periodic waveform using a generator having a capacitive-inductive resonating circuit.
6. The method as claimed in claim 1, comprising:
producing the periodic waveform using a generator that includes a saturable transformer having a feedback winding.
producing the periodic waveform using a generator that includes a saturable transformer having a feedback winding.
7. A method for breaking a chemical bond in a molecule comprising:
(a) introducing the molecule which is in a gas or vapour state to a discharge gap; and, (b) applying a periodic waveform having a fast rising leading edge and having a suitable voltage to at least partially ionize the molecule to the discharge gap to selectively break the chemical bond.
(a) introducing the molecule which is in a gas or vapour state to a discharge gap; and, (b) applying a periodic waveform having a fast rising leading edge and having a suitable voltage to at least partially ionize the molecule to the discharge gap to selectively break the chemical bond.
8. The method as claimed in claim 7, further comprising:
producing the fast rising leading edge to include a portion having a constant slope.
producing the fast rising leading edge to include a portion having a constant slope.
9. The method as claimed in claim 7, further comprising:
producing the periodic waveform to include a slow falling trailing edge.
producing the periodic waveform to include a slow falling trailing edge.
10. The method as claimed in claim 7, wherein the suitable voltage includes a range of voltages having an adjustable voltage increase rate.
11. The method as claimed in claim 10, further comprising:
adjusting the voltage increase rate of the fast rising leading edge to optimize the break down of the chemical bond.
adjusting the voltage increase rate of the fast rising leading edge to optimize the break down of the chemical bond.
12. The method as claimed in claim 11, further comprising:
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 6.6x10 6 volts/second, to thereby produce ozone gas from air.
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 6.6x10 6 volts/second, to thereby produce ozone gas from air.
13. The method as claimed in claim 11, further comprising:
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 234x10 6 volts/second, to thereby produce ozone gas from air.
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 234x10 6 volts/second, to thereby produce ozone gas from air.
14. The method as claimed in claim 11, further comprising:
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 233.5x10 6 volts/second, to thereby produce ozone gas from air.
adjusting the voltage increase rate of the fast rising leading edge to be substantially equal to 233.5x10 6 volts/second, to thereby produce ozone gas from air.
15. The method as claimed in claim 7, further comprising:
producing the periodic waveform using a generator having an inductive component.
producing the periodic waveform using a generator having an inductive component.
16. The method as claimed in claim 7, comprising:
producing the periodic waveform using a generator having a capacitive-inductive resonating circuit.
producing the periodic waveform using a generator having a capacitive-inductive resonating circuit.
17. The method claimed in claim 7, comprising:
producing the periodic waveform using a generator that includes a saturable transformer having a feedback winding.
producing the periodic waveform using a generator that includes a saturable transformer having a feedback winding.
18. An apparatus for breaking a chemical bond in a molecule, the molecule being in a gas or vapour state, the apparatus comprising:
a chamber for containing the molecule having two separate electrodes to which is applied a periodic waveform having a fast rising leading edge and having a suitable voltage to at least partially thereby ionize the molecule to break the chemical bond.
a chamber for containing the molecule having two separate electrodes to which is applied a periodic waveform having a fast rising leading edge and having a suitable voltage to at least partially thereby ionize the molecule to break the chemical bond.
19. The apparatus as claimed in claim 18, wherein the fast rising leading edge includes a portion having a constant slope.
20. The apparatus as claimed in claim 18, wherein the suitable voltage includes a range of voltages having an adjustable voltage increase rate.
21. The apparatus as claimed in claim 20, wherein the voltage increase rate of the fast rising leading edge is adjusted to optimize the break down of the chemical bond.
22. The apparatus as claimed in claim 21, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 6.6x10 6 volts/second, to thereby produce ozone gas from air.
23. The apparatus as claimed in claim 21, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 234x10 6 volts/second, to thereby produce ozone gas from air.
24. The apparatus as claimed in claim 21, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 233.5x10 6 volts/second, to thereby produce ozone gas from air.
25. The apparatus as claimed in claim 18, wherein the molecule is oxygen and at least a portion of the oxygen is ionized in the chamber to form ionized oxygen, at least a portion of the ionized oxygen recombines to form ozone and the apparatus further comprises an outlet in fluid communication with the chamber for receiving the ozone.
26. An apparatus for breaking a chemical bond in a molecule, the molecule being in a gas or vapour state, the apparatus comprising:
a chamber for containing the molecule having two separate electrodes; and an electrical signal generator configured to apply to the electrodes a periodic waveform having a fast rising leading edge and having a suitable voltage, to whereby at least partially ionize the molecule selectively to break the chemical bond.
a chamber for containing the molecule having two separate electrodes; and an electrical signal generator configured to apply to the electrodes a periodic waveform having a fast rising leading edge and having a suitable voltage, to whereby at least partially ionize the molecule selectively to break the chemical bond.
27. The apparatus as claimed in claim 26, wherein the fast rising leading edge includes a portion having a constant slope.
28. The apparatus as claimed in claim 26, wherein the suitable voltage includes a range of voltages having an adjustable voltage increase rate.
29. The apparatus as claimed in claim 28, wherein the voltage increase rate of the fast rising leading edge is adjusted to optimize the break down of the chemical bond.
30. The apparatus as claimed in claim 29, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 6.6x10 6 volts/second, to thereby produce ozone gas from air.
31. The apparatus as claimed in claim 29, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 234x10 6 volts/second, to thereby produce ozone gas from air.
32. The apparatus as claimed in claim 29, wherein the voltage increase rate of the fast rising leading edge is substantially equal to 233.5x10 6 volts/second, to thereby produce ozone gas from air.
33. The apparatus as claimed in claim 26, wherein the molecule is oxygen and at least a portion of the oxygen is ionized in the chamber to form ionized oxygen, at least a portion of the ionized oxygen recombines to form ozone and the apparatus further comprises an outlet in fluid communication with the chamber for receiving the ozone.
34. The apparatus as claimed in claim 26, wherein the electrical signal generator further comprises:
a capacitive component of a resident circuit formed by the two electrodes.
a capacitive component of a resident circuit formed by the two electrodes.
35. The apparatus as claimed in claim 26, wherein the periodic waveform further comprises a slow falling trailing edge.
36. The apparatus as claimed in claim 26, further comprising:
an output transformer forming an inductive component configured to apply the periodic waveform across the two electrodes.
an output transformer forming an inductive component configured to apply the periodic waveform across the two electrodes.
37. The apparatus as claimed in claim 26, wherein the electrical signal generator further comprises:
a capacitive-inductive resonating circuit.
a capacitive-inductive resonating circuit.
38. The apparatus as claimed in claim 26, wherein the electrical signal generator further comprises:
a saturable transformer having a feedback winding.
a saturable transformer having a feedback winding.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/336,237 | 1994-11-07 | ||
| US08/336,237 US5630990A (en) | 1994-11-07 | 1994-11-07 | Ozone generator with releasable connector and grounded current collector |
| CA002204353A CA2204353C (en) | 1994-11-07 | 1995-11-03 | Ozone generator |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002204353A Division CA2204353C (en) | 1994-11-07 | 1995-11-03 | Ozone generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2327558A1 CA2327558A1 (en) | 1996-05-17 |
| CA2327558C true CA2327558C (en) | 2002-08-27 |
Family
ID=25679295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002327558A Expired - Lifetime CA2327558C (en) | 1994-11-07 | 1995-11-03 | Ozone generator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2327558C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110054159A (en) * | 2019-05-26 | 2019-07-26 | 宁波市镇海怡福莱文化创意有限公司 | Ozone generator and attachment |
-
1995
- 1995-11-03 CA CA002327558A patent/CA2327558C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2327558A1 (en) | 1996-05-17 |
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