CA1059929A - Electronic air cleaner - Google Patents
Electronic air cleanerInfo
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- CA1059929A CA1059929A CA259,544A CA259544A CA1059929A CA 1059929 A CA1059929 A CA 1059929A CA 259544 A CA259544 A CA 259544A CA 1059929 A CA1059929 A CA 1059929A
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- air
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Abstract
S P E C I F I C A T I O N
ELECTRONIC AIR CLEANER
ABSTRACT OF THE DISCLOSURE
An electronic air cleaner, in which an air inlet, a mechanical prefilter, an electrifying cell, an electrostatic collector cell, a chemical filter and an air outlet are ar-ranged in the order in a casing of insulating material.
The electrifying cell comprises a grounded conductive pro-tection net located behind the mechanical prefilter, a plura-lity of thin-wire electrodes and a plurality of grounded con-ductive plates. The thin-wire electrodes are less than 50 microns in diameter and arranged in appropriate intervals at substantial rectangles with an air path from the air inlet to the air outlet. Each of the grounded conductive plates has one end attached to the protection net and backwardly ex-tending between adjacent two of the thin-wire electrodes along the air path. The electrostatic collector cell comprises the entending parts of the grounded conductive plates and a plu-rality of negative high voltage conductive plates respectively connected to the thin-wire electrodes and laid between the grounded conductive plates. A direct current voltage less than 4.2 kilo-volts is applied to the negative high voltage conductive plates. An electric fan causes a flow of air from the inlet to the outlet to perform highly effective air clean-ing under preventing the ozone development.
ELECTRONIC AIR CLEANER
ABSTRACT OF THE DISCLOSURE
An electronic air cleaner, in which an air inlet, a mechanical prefilter, an electrifying cell, an electrostatic collector cell, a chemical filter and an air outlet are ar-ranged in the order in a casing of insulating material.
The electrifying cell comprises a grounded conductive pro-tection net located behind the mechanical prefilter, a plura-lity of thin-wire electrodes and a plurality of grounded con-ductive plates. The thin-wire electrodes are less than 50 microns in diameter and arranged in appropriate intervals at substantial rectangles with an air path from the air inlet to the air outlet. Each of the grounded conductive plates has one end attached to the protection net and backwardly ex-tending between adjacent two of the thin-wire electrodes along the air path. The electrostatic collector cell comprises the entending parts of the grounded conductive plates and a plu-rality of negative high voltage conductive plates respectively connected to the thin-wire electrodes and laid between the grounded conductive plates. A direct current voltage less than 4.2 kilo-volts is applied to the negative high voltage conductive plates. An electric fan causes a flow of air from the inlet to the outlet to perform highly effective air clean-ing under preventing the ozone development.
Description
~0~99Z9 This invention relates to an improved electronic air cleaner, and more particularly to a cleaner utilizing dust electrification phenomenon caused by electric discharge.
There have been heretofore well known electronic air cleaners, or dust arrestors, each comprising a cell for electrifying the dust particles by electric discharge, and a cell for collecting the electrified particles. These dust arrestors may be operated either with a positive or negative supply voltage, and the arrestor with a negative voltage has 1.5 to 2 times better efficiency than ~hat with a positive voltage if the absolute values of those discharge voltages are equal to each other, although the ozone generated by the former is thrice as much as that by the latter. This is the reason why such an air cleaner as required to avoid the generation of ozone for the sake of environmental sani-tation employs a positive discharge voltage at the sacrifice of the efficiency, while the negative voltage discharge is often applied to the smoke eliminators where an importance is mainly placed to the dust collecting efficiency.
The discharge electrodes in the discharge cell are usua-lly wires of 100 microns or more in diameter for the mecha-nical rigidity. The wires of this thickness need a positive supply voltags of at least 10 kilovolts to discharge suffient electricity so as to obtain the desired efficiency.
Moreover, about all the charges dust particles must be collected to enhance the dust collecting efficiency.
As is described above, the dust particles charged at a positive or a negative potential in the charger cell are
There have been heretofore well known electronic air cleaners, or dust arrestors, each comprising a cell for electrifying the dust particles by electric discharge, and a cell for collecting the electrified particles. These dust arrestors may be operated either with a positive or negative supply voltage, and the arrestor with a negative voltage has 1.5 to 2 times better efficiency than ~hat with a positive voltage if the absolute values of those discharge voltages are equal to each other, although the ozone generated by the former is thrice as much as that by the latter. This is the reason why such an air cleaner as required to avoid the generation of ozone for the sake of environmental sani-tation employs a positive discharge voltage at the sacrifice of the efficiency, while the negative voltage discharge is often applied to the smoke eliminators where an importance is mainly placed to the dust collecting efficiency.
The discharge electrodes in the discharge cell are usua-lly wires of 100 microns or more in diameter for the mecha-nical rigidity. The wires of this thickness need a positive supply voltags of at least 10 kilovolts to discharge suffient electricity so as to obtain the desired efficiency.
Moreover, about all the charges dust particles must be collected to enhance the dust collecting efficiency.
As is described above, the dust particles charged at a positive or a negative potential in the charger cell are
- 2 -attracted to the grounded electrode in the collector cell.
The electrode must be so constructed as not to disturb the flow of air in the collector cell. For that end, the col-lector electrode is usually an assembly of parallel metalic plates laminated at appropriate spaces for the flow of air.
In the collector electrodes of known structures, the dust particles arrested at the collector electrodes have the same potential as that of the electrodes, and therefore those electrodes have such defect as to allow a part of the arrest-ed dust to disperse again into the air when exceeding their retentive capacities. To prevent dust dispersion and retain the collected dust at the electrodes, it has been proposed that oil is applied to the surface of the collector elect-rodes. In that case, periodic cleaning of the collector electrodes is required to avoid the clog that may increases the pressure loss against the air so as to maintain a good dust collection performance. Furthermore, the above mentioned cleaning work needs a plenty of manpower and a cleaning ap-paratus (e.g., an ultrasonic washer), requiring an increased cost for it. The requirement for that work could be easily understood from a fact that there are now some independent companies doing that work.
An ob~ect of the present invention is to provide a highly effective electronic air cleaner capable of providing suffi-cient discharge and preventing the ozone development, at a relatively low negative discharge voltage.
According to a feature of this invention, the above said discharge voltage is set at a negative value less than 4.2 kilovolts, and the diameter of the thin wire which serves as
The electrode must be so constructed as not to disturb the flow of air in the collector cell. For that end, the col-lector electrode is usually an assembly of parallel metalic plates laminated at appropriate spaces for the flow of air.
In the collector electrodes of known structures, the dust particles arrested at the collector electrodes have the same potential as that of the electrodes, and therefore those electrodes have such defect as to allow a part of the arrest-ed dust to disperse again into the air when exceeding their retentive capacities. To prevent dust dispersion and retain the collected dust at the electrodes, it has been proposed that oil is applied to the surface of the collector elect-rodes. In that case, periodic cleaning of the collector electrodes is required to avoid the clog that may increases the pressure loss against the air so as to maintain a good dust collection performance. Furthermore, the above mentioned cleaning work needs a plenty of manpower and a cleaning ap-paratus (e.g., an ultrasonic washer), requiring an increased cost for it. The requirement for that work could be easily understood from a fact that there are now some independent companies doing that work.
An ob~ect of the present invention is to provide a highly effective electronic air cleaner capable of providing suffi-cient discharge and preventing the ozone development, at a relatively low negative discharge voltage.
According to a feature of this invention, the above said discharge voltage is set at a negative value less than 4.2 kilovolts, and the diameter of the thin wire which serves as
- 3 -the discharge electrode is less than 50 microns. m e reasons for that are as follows:
(1) The rate of ozone generation can be decreased with a decreasing discharge voltage, regardless of the polarity of the supply voltage.
That is, the ozone generation can be almost supressed at a negative voltage of about 4.2 kilovolts or less.
(2) The thin wire forming a discharge electrode in the discharger cell can discharge enough electricity and give the dust enough electric charge for the desired dust arresting performance at a relatively lower discharge voltage, and therefore the dust collection efficiency is improved.
Moreover, the electronic air cleaner of this invention will further be improved in a dust collecting efficiency by adding such collector cell as a mechanical after-filter or a honeycomb component part after the electrostatic collec-tor electrode. The honeycomb structure, having sufficient mechanical strength by itself, needs no other reinforcing members, and hence it can be small in size and light in weight, faci-litating the manufacture and handling.
In accordance with this invention there is provided an electronic air cleaner, comprising: a casing of insulating material having an air inlet and an air outlet, a mechanical pre-filter placed in said casing at the air inlet; a grounded conductive protection net located in said casing behind said mechanical pre-filter; a plurality of thin-wire electrodes less than 50 microns in diameter arranged in appropriate inter-vals at substantial rectangles with an air path from the air inlet to the air outlet; a plurality of grounded conductive plates each having one end attached to said protection net and backwardly extending, between adjacent two of said thin-wire electrodes, along said air path, said thin wire electrodes forming a discharge cell together with said protection net and said grounded plates; an electrostatic collector cell including said extending parts of said grounded conductive plates and a plurality ~ _ 4 -,,, . .~, lOS99Z9 of negative high voltage conductive plates respectively connected to said thin-wire electrodes and laid between said grounded conductive plates;
a chemical ~ilter placed in said casing behind said electrostatic collect-or cell; an electric fan seated in said casing to cause a flow o~ air from said air inlet to said air outlet; and a negative direct-current high voltage power source o~ less than 4.2 kilo-volts connected across the ground and said high negative voltage conductive plates.
The principle, construction and operation o~ the present invention will be clearly understood from the ~ollowing description taken in conJunction with the accompanying drawings, in which:
Figure 1 shows a longitudinal section of an embodiment of the present invention;
Figure 2 is a perspective view including a cut-out part o~
charger and collector cells employed in this invention;
Fig. 3 shows a part of a horizontal section along a line A-Aa in Fig. 1 ;
Fig. 4A and 4~ are perspective views explanatory of fix-ing a thin wire of discharge electrode in this invention ;
Fig. 5 shows a longitutinal section of another embodi-ment of the present invention ;
Fig. 6 shows a longitudinal section of another embodi-ment of this invention ;
Fig. 7 is a perspective view of the honeycomb structure of the embodiment shown in Fig. 6 ; and Fig 8 is an elevational view of another example of the thin-wire discharge electrode in this invention.
With reference to Figs. 1 to 4~ an embodiment of the present invention will be described. A casing 18 of insulat-ing material has an air inlet 1~ at which a pre-filter 2 is provided for removing coarse particles. At the rear side of the filter 3, is provided a protection net 3 held at the ground potential. Grounded electrode 4 each consisting of conductor plates extending from the protection net 3 to the inner part are connected to and each supported by conductors 19 and arranged between high negative voltage plate electrodes 7, which are supported by insulators 5 ant jointly connected by conductors 6. Each high negative voltage plate electrode 7 has projections 8 forwardly extending to form an E-shaped plate. A thin-wire electrode 9 is supported at the top of the projections 8. Thus, the thin wire 9 is positioned at right angles to the flow of air. The protection net 3, the grounded electrodes 4 and the thin-wire discharge electrodes 9 form a discharge cell (i.e., a dust electrifying cell) 12A, and the grounded electrodes 4 and highHvoltage negative electrodes 7 form a collector cell 12B, which attracts the charged dust particles. In a case where the thin wire 9 has a thickness of 50 microns or less, it causes a sufficient amount of negative-voltage discharge under minimum ozone gene-ration. In a preferred embodiment of this invention, the thin-wire discharge electrode 9 is strained between the wire holders 8 of the Degative high voltage plate electrode 7 in accordance with the following procedure (shown in Fig. 4) in which an end of each wire holder 8 is partiall~ sheared and its incision edges are rounded as shown in Fig. 4A ; a thin-wire 9 is wrapped around the remainder part, and then the sheared part is put back in its former position to fixtedly support the wire as shown in Fig. 4B. This makes it sure to avoid such accident as the thin wire discharge elecerode 9 is disconnected during the installation work. Another pro-tection net 10 is placed behind the grounded electrodes 4, if neoessary, and is kept at the ground potential. The high voltage power source 13 has a negative electrode connected to the electrodes 7 and 9, and a positlve electrode connected to the electrode 19 which is placed inside the casing 18 and held at the ground po~ential. A chemical filter 14 placed at the rear of the protection net 10 contains activated char-coal or catalyæer for removing hanmful substances. An elect-ric cross flow fan 15 is provided to take in the polluted air from the air inlet 1 and let out the cleaned air to an air outlet 16. If necessary, a protection net 17 is attached around the chemical filter 14.
In operation, the high voltage power source 13 supplies a negative voltage to the discharge electrodes 9 causing dis-charge in the discharge cell 12A. The fan 15 serves to take in the polluted air from the air inlet 1. The air loses co-arse dust particles when passing through the mechanical pre-filter 2. The remaining fine particles having passed the filter 2 are negatively charged at the electrifying cell 12A
on the principle of 'electrostatic dust collection'. Those particles are attracted to the grounded electrodes 4 in the collector cell 12B and arrested thereupon. When the air fin-ally passes the chemical Eilter 14~ the finer dust particles~smell, and other harmful remainders are eliminated. The air, thus cleaned, is sent out from the air outlet 16.
The electronic air cleaner according to the present in-vention generates ozone only at 0.01 ppm rate under a discharge voltage of -4 kilovolts. As the discharge voltage used is low, the insulation against the hi8h voltage is easy so that the power source and other parts supplied with high voltages can be made small and light. As the electronic air cleaner accord-ing to the present invention uses a negative voltage, the dis-charge power source can also be commonly used as the powersource of negative ion generator usually provided in an electro-nic air cleaner of this kind. This means a fact that the en-tire structure can be constructed in a small and compact size.
A conventional electronic air cleaner, employing a positive voltage discharge power source, needs to provide either another negative power source for the negative ion generation or a power supplying circuit with a special device to make the posi-tive power source available for the negative ion generation.
In accordance with this invention, the discharging pheno-menon is easy to occur at a lower voltage, because each dis-charge electrodes 9 is surrounded by the upper and the lower plate electrodes 4 and the grounded protection net 3 laid across the front ends of the electrodes 9. Thus, the struct-ure described above has the advantage of making it easy to electrify the dust particles. As the thin-wire discharge electrode 9 is covered by the plate electrodes 4 and the pro-tection net 3, it is mechanically protected against discon-nection by accidental touch during an inspection work.
Besides~ the electrodes 4 and the net 3 do not cause any elect-ric shock to an inspector as they are at the ground potential.
With reference to Fig. 5, another embodiment of the pre.
sent invention will next be described. The constitution of this embodiment differs from that of the first embodiment at the point that a mechanical after-filter 11 is inserted bet-ween the electrostatic collector cell 12B and the chemical filter 14. In Fig. 5, the same parts as those of the first embodiment are given by the same reference numerals. The dust particles are attracted each other and become coarse particles when passing through the discharge cell 12A, and therefore according to this embodiment the dust particles having passed through the collector cell 12B are arrested at the mechanical after-filter 11~ That means the dust collect-ion efficiency is improved.
With reference to Fig. 6, another embodiment of this invention will be described. In this embodiment, a honeycomb type collector electrode 20 is placed between the chemical filter 14 and the electrostatic collector cell 12B. In Fig.
6, the same parts as those of the first embodiment are marked 105992g w$th the same reference numerals. The honeycomb electrode 20, being at the ground potential, serves to improve the dust col-lection efficiency, because it collects in an electrostatic way the charged particles that were not caught at the electro-static collector cell 12B. The honeycomb collector electrode 20 may be made of aluminum (e.g. a thickness of 0.05 mm) or other metal sheets, metalized papers, or conductive plastics, and is preferably a combination of hexagonal cylinders as shown in Fig. 7. The cell size "al~ (Fig. 7) may be chosen at an appropriate value. The honeycomb type collector electrode 20 employed in this invention can be produced only by cutting in a desired size the honeycomb component part being on sale un-der the trade mark "A~UMI-HONEYCOMB". Since such a part made of very l~ght aluminum with a space factor of only about three percent has the sufficient mechanical rigidity by itself and does not need any special frame or reinforcement, reducing the weight and cost, it is suitable for the application to the vehi-cles, e.g., airplanes and cars, under a low weight and cost.
In addition, it may be thrown away after use. Furthermore, the honeycomb collector electrode 20 is easily replaced by a new one, cleaned, or removed, when constructed in a cartridge form~
The discharge electrode 9 may have such structure as shown in Fig. ô. The discharge electrode of Fig. 8 has a num-ber of short and fine discharge wires 22 (those wires are nomore than 50 microns in thickness) fixed in a crosswise form at appropriate intervals on a relatively long and thick con-ductive support wire 21~ which is strained between the wire holder 8 of the negative high voltage plate 7. Th$s structure can be produced by welding, studding or some other process.
Under this structure, since the discharge fine wires 22 can be minimized in thickness, the mechanical strength of the discharge electrode can be improved by the support wire 21 while producing sufficient discharge at a lower voltage.
As mentioned above, a highly effective electronic air cleaner can be provided in accordance with this invention, which comprises a mechanical after-filter or a honeycomb electrode type filter as well as an electrostatic collector electrode for collecting the charged dust particles. The electrostatic collector electrodes can be formed to be readily renewed and cleaned with a little expense. Moreover, a small and light electronic air cleaner can be provlded in accord-ance with this invention under equipment with light and read-ily replaceable electrostatic collector electrodes having ahigh dust collection efficiency and suitable for motor vehi-cle application.
- 10 _
(1) The rate of ozone generation can be decreased with a decreasing discharge voltage, regardless of the polarity of the supply voltage.
That is, the ozone generation can be almost supressed at a negative voltage of about 4.2 kilovolts or less.
(2) The thin wire forming a discharge electrode in the discharger cell can discharge enough electricity and give the dust enough electric charge for the desired dust arresting performance at a relatively lower discharge voltage, and therefore the dust collection efficiency is improved.
Moreover, the electronic air cleaner of this invention will further be improved in a dust collecting efficiency by adding such collector cell as a mechanical after-filter or a honeycomb component part after the electrostatic collec-tor electrode. The honeycomb structure, having sufficient mechanical strength by itself, needs no other reinforcing members, and hence it can be small in size and light in weight, faci-litating the manufacture and handling.
In accordance with this invention there is provided an electronic air cleaner, comprising: a casing of insulating material having an air inlet and an air outlet, a mechanical pre-filter placed in said casing at the air inlet; a grounded conductive protection net located in said casing behind said mechanical pre-filter; a plurality of thin-wire electrodes less than 50 microns in diameter arranged in appropriate inter-vals at substantial rectangles with an air path from the air inlet to the air outlet; a plurality of grounded conductive plates each having one end attached to said protection net and backwardly extending, between adjacent two of said thin-wire electrodes, along said air path, said thin wire electrodes forming a discharge cell together with said protection net and said grounded plates; an electrostatic collector cell including said extending parts of said grounded conductive plates and a plurality ~ _ 4 -,,, . .~, lOS99Z9 of negative high voltage conductive plates respectively connected to said thin-wire electrodes and laid between said grounded conductive plates;
a chemical ~ilter placed in said casing behind said electrostatic collect-or cell; an electric fan seated in said casing to cause a flow o~ air from said air inlet to said air outlet; and a negative direct-current high voltage power source o~ less than 4.2 kilo-volts connected across the ground and said high negative voltage conductive plates.
The principle, construction and operation o~ the present invention will be clearly understood from the ~ollowing description taken in conJunction with the accompanying drawings, in which:
Figure 1 shows a longitudinal section of an embodiment of the present invention;
Figure 2 is a perspective view including a cut-out part o~
charger and collector cells employed in this invention;
Fig. 3 shows a part of a horizontal section along a line A-Aa in Fig. 1 ;
Fig. 4A and 4~ are perspective views explanatory of fix-ing a thin wire of discharge electrode in this invention ;
Fig. 5 shows a longitutinal section of another embodi-ment of the present invention ;
Fig. 6 shows a longitudinal section of another embodi-ment of this invention ;
Fig. 7 is a perspective view of the honeycomb structure of the embodiment shown in Fig. 6 ; and Fig 8 is an elevational view of another example of the thin-wire discharge electrode in this invention.
With reference to Figs. 1 to 4~ an embodiment of the present invention will be described. A casing 18 of insulat-ing material has an air inlet 1~ at which a pre-filter 2 is provided for removing coarse particles. At the rear side of the filter 3, is provided a protection net 3 held at the ground potential. Grounded electrode 4 each consisting of conductor plates extending from the protection net 3 to the inner part are connected to and each supported by conductors 19 and arranged between high negative voltage plate electrodes 7, which are supported by insulators 5 ant jointly connected by conductors 6. Each high negative voltage plate electrode 7 has projections 8 forwardly extending to form an E-shaped plate. A thin-wire electrode 9 is supported at the top of the projections 8. Thus, the thin wire 9 is positioned at right angles to the flow of air. The protection net 3, the grounded electrodes 4 and the thin-wire discharge electrodes 9 form a discharge cell (i.e., a dust electrifying cell) 12A, and the grounded electrodes 4 and highHvoltage negative electrodes 7 form a collector cell 12B, which attracts the charged dust particles. In a case where the thin wire 9 has a thickness of 50 microns or less, it causes a sufficient amount of negative-voltage discharge under minimum ozone gene-ration. In a preferred embodiment of this invention, the thin-wire discharge electrode 9 is strained between the wire holders 8 of the Degative high voltage plate electrode 7 in accordance with the following procedure (shown in Fig. 4) in which an end of each wire holder 8 is partiall~ sheared and its incision edges are rounded as shown in Fig. 4A ; a thin-wire 9 is wrapped around the remainder part, and then the sheared part is put back in its former position to fixtedly support the wire as shown in Fig. 4B. This makes it sure to avoid such accident as the thin wire discharge elecerode 9 is disconnected during the installation work. Another pro-tection net 10 is placed behind the grounded electrodes 4, if neoessary, and is kept at the ground potential. The high voltage power source 13 has a negative electrode connected to the electrodes 7 and 9, and a positlve electrode connected to the electrode 19 which is placed inside the casing 18 and held at the ground po~ential. A chemical filter 14 placed at the rear of the protection net 10 contains activated char-coal or catalyæer for removing hanmful substances. An elect-ric cross flow fan 15 is provided to take in the polluted air from the air inlet 1 and let out the cleaned air to an air outlet 16. If necessary, a protection net 17 is attached around the chemical filter 14.
In operation, the high voltage power source 13 supplies a negative voltage to the discharge electrodes 9 causing dis-charge in the discharge cell 12A. The fan 15 serves to take in the polluted air from the air inlet 1. The air loses co-arse dust particles when passing through the mechanical pre-filter 2. The remaining fine particles having passed the filter 2 are negatively charged at the electrifying cell 12A
on the principle of 'electrostatic dust collection'. Those particles are attracted to the grounded electrodes 4 in the collector cell 12B and arrested thereupon. When the air fin-ally passes the chemical Eilter 14~ the finer dust particles~smell, and other harmful remainders are eliminated. The air, thus cleaned, is sent out from the air outlet 16.
The electronic air cleaner according to the present in-vention generates ozone only at 0.01 ppm rate under a discharge voltage of -4 kilovolts. As the discharge voltage used is low, the insulation against the hi8h voltage is easy so that the power source and other parts supplied with high voltages can be made small and light. As the electronic air cleaner accord-ing to the present invention uses a negative voltage, the dis-charge power source can also be commonly used as the powersource of negative ion generator usually provided in an electro-nic air cleaner of this kind. This means a fact that the en-tire structure can be constructed in a small and compact size.
A conventional electronic air cleaner, employing a positive voltage discharge power source, needs to provide either another negative power source for the negative ion generation or a power supplying circuit with a special device to make the posi-tive power source available for the negative ion generation.
In accordance with this invention, the discharging pheno-menon is easy to occur at a lower voltage, because each dis-charge electrodes 9 is surrounded by the upper and the lower plate electrodes 4 and the grounded protection net 3 laid across the front ends of the electrodes 9. Thus, the struct-ure described above has the advantage of making it easy to electrify the dust particles. As the thin-wire discharge electrode 9 is covered by the plate electrodes 4 and the pro-tection net 3, it is mechanically protected against discon-nection by accidental touch during an inspection work.
Besides~ the electrodes 4 and the net 3 do not cause any elect-ric shock to an inspector as they are at the ground potential.
With reference to Fig. 5, another embodiment of the pre.
sent invention will next be described. The constitution of this embodiment differs from that of the first embodiment at the point that a mechanical after-filter 11 is inserted bet-ween the electrostatic collector cell 12B and the chemical filter 14. In Fig. 5, the same parts as those of the first embodiment are given by the same reference numerals. The dust particles are attracted each other and become coarse particles when passing through the discharge cell 12A, and therefore according to this embodiment the dust particles having passed through the collector cell 12B are arrested at the mechanical after-filter 11~ That means the dust collect-ion efficiency is improved.
With reference to Fig. 6, another embodiment of this invention will be described. In this embodiment, a honeycomb type collector electrode 20 is placed between the chemical filter 14 and the electrostatic collector cell 12B. In Fig.
6, the same parts as those of the first embodiment are marked 105992g w$th the same reference numerals. The honeycomb electrode 20, being at the ground potential, serves to improve the dust col-lection efficiency, because it collects in an electrostatic way the charged particles that were not caught at the electro-static collector cell 12B. The honeycomb collector electrode 20 may be made of aluminum (e.g. a thickness of 0.05 mm) or other metal sheets, metalized papers, or conductive plastics, and is preferably a combination of hexagonal cylinders as shown in Fig. 7. The cell size "al~ (Fig. 7) may be chosen at an appropriate value. The honeycomb type collector electrode 20 employed in this invention can be produced only by cutting in a desired size the honeycomb component part being on sale un-der the trade mark "A~UMI-HONEYCOMB". Since such a part made of very l~ght aluminum with a space factor of only about three percent has the sufficient mechanical rigidity by itself and does not need any special frame or reinforcement, reducing the weight and cost, it is suitable for the application to the vehi-cles, e.g., airplanes and cars, under a low weight and cost.
In addition, it may be thrown away after use. Furthermore, the honeycomb collector electrode 20 is easily replaced by a new one, cleaned, or removed, when constructed in a cartridge form~
The discharge electrode 9 may have such structure as shown in Fig. ô. The discharge electrode of Fig. 8 has a num-ber of short and fine discharge wires 22 (those wires are nomore than 50 microns in thickness) fixed in a crosswise form at appropriate intervals on a relatively long and thick con-ductive support wire 21~ which is strained between the wire holder 8 of the negative high voltage plate 7. Th$s structure can be produced by welding, studding or some other process.
Under this structure, since the discharge fine wires 22 can be minimized in thickness, the mechanical strength of the discharge electrode can be improved by the support wire 21 while producing sufficient discharge at a lower voltage.
As mentioned above, a highly effective electronic air cleaner can be provided in accordance with this invention, which comprises a mechanical after-filter or a honeycomb electrode type filter as well as an electrostatic collector electrode for collecting the charged dust particles. The electrostatic collector electrodes can be formed to be readily renewed and cleaned with a little expense. Moreover, a small and light electronic air cleaner can be provlded in accord-ance with this invention under equipment with light and read-ily replaceable electrostatic collector electrodes having ahigh dust collection efficiency and suitable for motor vehi-cle application.
- 10 _
Claims (10)
1. An electronic air cleaner, comprising :
a casing of insulating material having an air inlet and an air outlet ;
a mechanical pre-filter placed in said casing at the air inlet ;
a grounded conductive protection net located in said cas-ing behind said mechanical prefilter ;
a plurality of thin-wire electrodes less than 50 microns in diameter arranged in appropriate intervals at substantial rectangles with an air path from the air inlet to the air outlet ;
a plurality of grounded conductive plates each having one end attached to said protection net and backwardly extend-ing, between adjacent two of said thin-wire electrodes, along said air path, said thin wire electrodes forming a discharge cell together with said protection net and said grounded plates ;
an electrostatic collector cell including said extend-ing parts of said grounded conductive plates and a plurality of negative high voltage conductive plates respectively con-nected to said thin-wire electrodes and laid between said grounded conductive plates ;
a chemical filter placed in said casing behind said electrostatic collector cell ;
an electric fan seated in said casing to cause a flow of air from said air inlet to said air outlet ; and a negative direct-current high voltage power source of less than 4.2 kilo-volts connected across the ground and said high negative voltage conductive plates.
a casing of insulating material having an air inlet and an air outlet ;
a mechanical pre-filter placed in said casing at the air inlet ;
a grounded conductive protection net located in said cas-ing behind said mechanical prefilter ;
a plurality of thin-wire electrodes less than 50 microns in diameter arranged in appropriate intervals at substantial rectangles with an air path from the air inlet to the air outlet ;
a plurality of grounded conductive plates each having one end attached to said protection net and backwardly extend-ing, between adjacent two of said thin-wire electrodes, along said air path, said thin wire electrodes forming a discharge cell together with said protection net and said grounded plates ;
an electrostatic collector cell including said extend-ing parts of said grounded conductive plates and a plurality of negative high voltage conductive plates respectively con-nected to said thin-wire electrodes and laid between said grounded conductive plates ;
a chemical filter placed in said casing behind said electrostatic collector cell ;
an electric fan seated in said casing to cause a flow of air from said air inlet to said air outlet ; and a negative direct-current high voltage power source of less than 4.2 kilo-volts connected across the ground and said high negative voltage conductive plates.
2. An electronic air cleaner according to claim 1, in which each of said thin-wire discharge electrodes is strained through forwardly extended projections of said negative high voltage plates.
3. An electronic air cleaner according to claim 2, in which said thin-wire discharge electrodes are each wrapped around at the sheared gaps provided at the projections.
4. An electronic air cleaner according to claim 1, in which each of said thin-wire discharge electrodes comprises a con-ductive support wire, strained through forwardly extended pro-jections of said negative high voltage plates, and a number of fine wires fixed on the support wire at appropriate intervals at substantial rectangles with said air path.
5. An electronic air cleaner according to claim 1, further including a mechanical after-filter provided between said electrostatic collector cell and said chemical filter.
6. An electronic air cleaner according to claim 5, in which each of said thin-wire discharge electrodes is strained through forwardly extended projections of said negative high voltage plates.
7. An electronic air cleaner according to claim 5, in which each of said thin-wire discharge electrodes comprises a con-ductive support wire, strained through forwardly extended pro-jections of said negative high voltage plates, and a number of fine wires fixed on the support wire at appropriate inter-vals at substantial rectangles with said air path,
8. An electronic air cleaner according to claim 1, further including a honeycomb type electrostatic collector electrodes placed between said electrostatic collector cell and said chemical filter.
9. An electronic air cleaner according to claim 8, in which each of said thin-wire discharge electrodes is strained through forwardly extended projections of said negative high voltage plates.
10. An electronic air cleaner according to claim 8, in which each of said thin-wire discharge electrodes comprises a con-ductive support wire, strained through forwardly extended pro-sections of said negative high voltage plates, and a number of fine wires fixed on the support wire at appropriate inter-vals at substantial rectangles with said air path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA259,544A CA1059929A (en) | 1976-08-20 | 1976-08-20 | Electronic air cleaner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA259,544A CA1059929A (en) | 1976-08-20 | 1976-08-20 | Electronic air cleaner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059929A true CA1059929A (en) | 1979-08-07 |
Family
ID=4106699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA259,544A Expired CA1059929A (en) | 1976-08-20 | 1976-08-20 | Electronic air cleaner |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059929A (en) |
-
1976
- 1976-08-20 CA CA259,544A patent/CA1059929A/en not_active Expired
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