US2191595A - Magnetically controlled gaseous discharge device - Google Patents

Description

Feb. 27, 1940. P, L, 'SPENCER 2,191,595

MAGNETICALLY CONTROLLED GASEOUS DISCHARGE DEVICE Filed Feb. 11, 1938 2 Sheets-Sheet l mam? PE/FC y Z. SPENCER Feb. 27, 1940. P. L. SPENCER 2,191,595

MAGNETICALLY CONTROLLED GASEOUS DISCHARGE DEVICE Filed Feb. 11, 1938 2 Sheets-Sheet 2 A 0.105 TABL E fiEcT/F/me 26 PHASE SH/FT ADJUSTABLE o- 2 flows TABLE RES/5 70B 26 171106721 707 PERCY L. SPENCER "UNITED STATES PATENT OFFICE Y a I f 7 1,101,351," I I manna-romp oon'raomnn Games I. msomonnmoa Percy 1L. Spencer, West Romany Mass; assign'or' v to Raytheo'n Manufacturin Oomn nmNewton, Massua' corporationofll'elaware,

Application '11, .1933, Ho. 190m This invention relates to controlled' gaseous dispassing through the electrode 5, it is intended that charge devices, and more particularly tol-suclii-v these expressions shall include those conditionsin devices in which the time of'starting of an ionwhich the electrode partially surrounds the izing discharge between the electrodes is' condischarge path to an extent sufficient to accomtrolled by means of a magnetic fleld. Y plish-the type of control hereinafter described. 5 I

An object of my invention is to provide such The envelope .I is provided with a reentrant a magnetically controlled tube which is capable stem 8 at each end thereof, each of which stems of conducting and controlling large values of cursupports one of the cathodes 4 and one of the rents flowing in either or both directions through intermediate electrodes 5. Each cathode 4 prefsaid tube under substantial applied voltages. erably' consists of a hollow member 9, preferably Another object of this invention is to produce of some. metal such as nickel provided with a such a device which is flexible in control and; plurality of internal radially disposed metal fins which is adapted to accomplish a wide variety of Ill. The metal fins and also the interior of the control operations. hollow member 9 are coated with an electron- II The foregoing and other objects of my invenemissive material, such as, for example, alkaline ll tionwill be best understood from the following earth oxides. In order to heat the coated surdescription of an exempliflcation thereof, referfaces of the cathode 4 to temperature of therence being had to the accompanying drawings mionic emission, a heating filament II is disposed wherein: within the hollow member 9. The heating filam Fig. l is a cross-sectional view of one embodiment I I may consist of'a single helix of a re- Q ment of my invention showing my novel discharge fractory conductor, such as tungsten, and is electube together with a diagrammatic representatrically connected at its upper end to the hollow tion of a circuit whch may be used therewith; member 9 by being welded} to one of the fins I0. and} In order to prevent excessive radiation of heat Figs. 2, 3 and 4 are diagrammatic representafrom the hollow member 9, it is surrounded by :5 tions of various types of control current supply means of a heat shield I2. Each cathode asfor Fig. 1. sembly 4 is supported on the stem 8 by means In Fig. 1, I represents a hermetically sealed of a pair of conducting standards I3 which are envelope, preferably of glass, having enlarged sealed in the press 8. One of the standards I3 end chambers 2 at each end thereof, said enis sealed] through said press so as to provide an 30 larged chambers being connected by a tubular external electrical connection to the cathode 4. intermediate section 3. In each enlarged cham- The lower end of the heating filament II is pro her 2 is mounted a cathode 4. Adjacent each vided with a lead I4 which is likewise sealed cathode 4 and surrounding the discharge path through the press 8 so as to provide an external terminating at said electrodes is an intermediate electrical connection thereto. In the drawings 5 control electrode 5. The electrode 5 is preferit will be seen that the cathode 4 at the rightably made of non-magnetic material, and" may hand end is shown in cross-section. However, it comprise a cylinder of sheet metal, such as nonis to be understood that the cathode 4 at the left magnetic nickel, tantalum or carbon. Since each is of identically the same structure as that shown a, electrode 5 will also operate as an anode, as will at the right-hand end. be hereinafter described, it is preferred that the In order to support each of the intermediate material of which the electrode 5 is constituted electrodes 5 in position adjacent each cathode 4, shall be relatively refractory. The electrodes 5, each electrode 5 is provided with a pair of conas shown, are each provided with an end plate 6 ducting standards I5, which are sealed in the 4| having a relatively large opening 1 passing thererespective press 8. In each case one of the standthrough. The opening I therefore permits a disards I5 is sealed through its press 8 so as to procharge to pass from each cathode 4 through the vide an external electrical connection to its asadjacent opening 1 to the opposite electrode 5 as sociated electrode 5. an anode. Of course each electrode 5 may be of The envelope I containing the construction as a any other suitable form, and it is possible to make described above, after being thoroughly evacuated it so that it does not completely surround the in accordance with the usual practice, is filled discharge path but only partially surrounds it. with some suitable ionizable medium. This In the specification and claims, whenever the medium maybe ametallic vapor, such as mercury electrode 5 is defined as surrounding the disvapor, or a gas, such as one of the noble gases,

charge path or when the discharge is, described as or a mixture thereof. When mercury vapor is u used, pressures in the range of one to one hundred microns are preferred, while in the case of a noble gas, such as argon, a pressure of the order of one millimeter or less is preferred. In any event, the gas preferably is of a suitable value so that when a discharge across the gas or vapor becomes ionized, a current fiows at a relatively low voltage drop.

In order to supply power to the device, there is provided a supply transformer l6 having a primary I1 and a secondary IS. The primary I1 is adapted to be connected to some suitable source of alternating current. A conductor l9 connects one end of the secondary l8 to one of the leads I3, and thus to one of the cathodes 4, for example the right-hand cathode. A conductor 20 extends from the opposite end of the secondary l8 to a load{ 2|. The other side of the load is connected by means of a lead 22 to the other conductor l3, and thus to the other cathode 4. Each pair of conductors I3 and I4 is adapted to be connected to a suitable source of heating current, whereby the heating filament II in each case is raised to its operating temperature. The external conductor I5 of each intermediate electrode 5 is connected} by means of a conductor I5 to the adjacent lead I3, and in this way each intermediate electrode 5 is connected to its adjacent cathode 4.

Upon supplying heating current to each pair of conductors l3 and [4, the filament II and consequently the coated surfaces of each cathode 4 will be raised to a temperature at which said coated surfaces emit a copious supply of electrons thermionically. -As each cathode 4 becomes negative, the electrode 5 associated with the opposite cathode 4 will become positive, and thus will act as an anode with respect to the negative cathode. Under these conditions, the electrons emitted from the negative cathode will flow through its adjacent electrode 5, through its discharge opening I to the opposite electrode 5. This flow of electrons will produce intense ionization of the gas within the envelope, and current at a relatively low voltage drop will flow between the negative cathode 4 and the positive electrode 5. Since these conditions are reversed with each reversal of the applied voltage, it will be seen that currents will flow through the tube l in both directions, and an alternating current will be delivered to the load 2|.

As more fully described and claimed in my copending application, Serial No. 612,235, filed May 19, 1932, now Patent No. 2,124,682, for an improvement in Electrical gaseous discharge devices, a discharge of the type which I have described above is prevented from starting when a magnetic field of a predetermined, magnitude, intercepting the direction of said discharge, is impressed across the space within the intermediate electrode 5. This transverse magnetic field may be applied in any suitable manner. For example, I have shown a pair of magnetic pole pieces 23 disposed on opposite sides of each intermediate electrodie 5 outside of the tubular portion 3. Each pair of pole pieces 23 may form part of a unitary core structure. In order to energize each of said core structures and said magnetic pole pieces, energizing or control coils 24 are provided for each of the pole pieces 23. The energizing coils 24 associated with each pair of pole pieces 23 are fed with current through a control device 25 which may be energized from any suitable source. As indicated inthe drawings, this source may be the transformer Hi. In this case a pair of conductors 28 are provided connecting the input to each control device 25 in parallel, and a pair of conductors 21 connect the two leads 28 to opposite sides of the secondary winding l8. Although -I have described each intermediate electrode 5 as being provided with a separate pair of pole pieces, a single pair of pole pieces could. be provided if such a magnetic structure were made sufliciently large to set up a transverse magnetic field in the space within both of the intermediate electrodes 5. However, in the interest of more flexible control, the construction as described in the drawings is preferred.

When the device is energized, as described above, and a discharge tends to flow alternately from each cathode 4 to the opposite electrode 5, it will be seen that such a discharge must pass through the intermediate electrode adjacent its associated cathode. Under these conditions, when a magnetic field is set up by each pair of pole pieces 23 intercepting the discharge passing through said intermediate electrode 5, the initiation of the discharge will be delayed for a predetermined part of the voltage cycle, depending upon the relative value of the magnetic field and the applied voltage. In most instances the discharge can be considered as being initiated whenever the magnetic field falls to substantially a zero value. In order to accomplish different types of control, the control devices 25 may be constructed, for example, to supply to the coils 24 a controllable direct current, as indicated in Fig. 2. Also each control device 25 might be constructed to supply to the energizing coils 24 a variable current of the same frequency as that supplied to the transformer l6. One arrangement might be that indicated in Fig. 3 wherein each control device 25 would} be constructed so as to shift the phase of the current supplied to the coils 24 with respect to the voltage supplied to the transformer l6. Another arrangement might be to construct each control device 25 as an adjustable resistor, as indicated in Fig. 4, whereby alternating current varying in magnitude pending application mentioned above, and also i in my copending application, Serial No. 188,887, filed February 5, 1938, for an improvement in Controlled gaseous discharge devices. Briefly these types of controls might be summarized as follows.- When variable amounts of direct current are supplied to the coils 24, (Fig. 2) alternating currents will flow in the load 2| and will be controlled in magnitude. When alternating current varying in phase (Fig. 3) or magnitude (Fig. 4) is supplied to the coils 24, likewise alternating current of varying magnitude will be supplied to the load 2|. One type of control is that in which magnetic pole pieces 23 are biased with a certain amount of unidirectional flux, either by being constructed as a permanent magnet or by having the coils 24 supplied with a direct current component, and in addition being supplied with an alternating component of flux by feeding an alternating component of current to the coils 24. Under these conditions, the device may be made to supply rectified current to the load 2|, the polarity of said. direct current depending upon the phase relationship of the alternating current component of the flux with respect tothe voltage applied to the tube. Fur- 75 thermore, under these conditions, variation in said phase relationship will produce variation in the magnitude of the direct current supplied to the load.

This invention is not limited to the particular details of construction or operation as described above as many equivalents will suggest them selves to those skilled in the art. For example, the electrodes can take a variety 01 forms. Furthermore, various combinations of circuits and controls may be impressed upon the tube, producing a wide variety of devices of operation. It is accordingly desired, therefore, that the equivalents which come within the scope of the appended claims be considered as being included within the scope of the invention.

What is claimed is:

1. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two cathodes, two intermediate electrodes, each adjacent one of said cathodes, each intermediate electrode having a discharge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other of said intermediate electrodes as an anode, and means for producing a magnetic field which is transverse to the direction of each of said discharges adjacent each intermediate electrode.

2. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two thermionic oathodes, two intermediate electrodes, each adjacent one of said cathodes, each intermediate electrode having a discharge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other of said intermediate electrodes as an anode, and means for producing a magnetic field which is transverse to the direction of each oi said discharges adjacent each intermediate electrode.

3. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two thermionic cathodes, two intermediate electrodes, each adjacent one 01 said cathodes, each of said intermediate electrodes being connected to its adjacent cathode, each intermediate electrode having a discharge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other of said intermediate electrodes as an anode, and means for producing a magnetic field which is transverse to the direction of each of said discharges adjacent each intermediate electrode.

4. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two thermionic cathodes, two intermediate electrodes, each adjacent one of said cathodes, each of said intermediate electrodes being connected to its adjacent cathode, each intermediate electrode having a dis charge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other oi! said intermediate electrodes as an anode, means for. producing a magnetic field which is transverse to the direction of each of said discharges adjacent each intermediate electrode.

5. In combination, an electrical space dis charge device comprising an envelope containing an ionizable atmosphere, two thermionic odes, two intermediate electrodes, each adjacent one of said cathodes, each intermediate electrode having a discharge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other of said intermediate electrodes as an anode, means for producing a magnetic field which is transverse to the direction of each of said discharges adjacent each intermediate electrode, and means for controlling said magnetic fields for controlling said discharges.

6. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two thermionic cathodes, two intermediate electrodes, each adjacent one of said cathodes, each intermediate electrode having a discharge passage through it in the direction of the other of said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other of said intermediate electrodes as an anode, means for producing a magnetic field which is transverse to the direction of each or said discharges adjacent each intermediate electrode, and means for controlling the magnitude of said magnetic fields for controlling said discharges.

I. In combination, an electrical space discharge device comprising an envelope containing an ionizable atmosphere, two thermionic cathodes, two intermediate electrodes, each adjacent one of said cathodes, each of said intermediateelectrodes being connected to its adjacent cathode, each intermediate electrode having a discharge passage through it in the direction of the other 01' said intermediate electrodes, whereby a discharge may pass from each cathode past one of said intermediate electrodes to the other 01' said intermediate electrodes as an anode, means for producing a varying magnetic field which is transverse to the direction of each of said discharges adjacent each intermediate electrode, means for connecting a source of alternating current between said cathodes, and means for controlling the phase angles between said magnetic fields and said source for controlling said discharges.

PERGY L. SPENCER.

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