US2481365A

US2481365A - Gaseous discharge device

Info

Publication number: US2481365A
Application number: US698061A
Authority: US
Inventors: Paul W Stutsman
Original assignee: Raytheon Manufacturing Co
Current assignee: Raytheon Co
Priority date: 1946-09-19
Filing date: 1946-09-19
Publication date: 1949-09-06
Anticipated expiration: 1966-09-06

Description

W @949 P. W. STUTSMAN GASEOUS DISCHARGE DEVICE Filed Sept. 19, 1946 m w W U G TB W MW J/ V5 T N A L U Y v M@ Patented Sept. 6, 1949 GASEOUS DISCHARGE DEVICE Paul W. Stutsman, Needham, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application September 19, 1946, Serial No. 698,061 '7 Claims. (01. 25027.5)

This invention relates to gaseous discharge devices, and more particularly to such devices employing a pair of starting electrodes between which a glow discharge is effected to initiate a discharge through the main cathode-anode circuit of the tube.

In my copending application, Serial No. 647,- 463, filed February 14, 1946, now United States Patent No. 2,435,246, issued February 3, 1948, a gaseous discharge device is disclosed having, beside the" two main electrodes, a third electrode having a portion spaced a distance from the efiective area of one of'the said main electrodes substantially equal to the minimum breakdownpotential distance. A glow discharge initiated between the main electrode and the third electrode ionizes the gas in the space between the two main electrodes which are spaced at a distance substantially greater than the minimum breakdown-potential distance. Such a construction provides a tube which greatly facilitates the initiation of the main discharge.

The present invention is based upon the discovery that the starting glow discharge may be more readily initiated by providing a pair of starting electrodes between either of which and one of the main electrodes or between each other the glow discharge may be initiated. One of the two starting electrodes constitutes an auxiliary cathode and the other a starting anode. The construction provides a discharge device in which a minimum output is required to ionize the anode space.

The above and other objects and features of the invention will be made fully apparent to those skilled in the art from a consideration of the following detailed description taken in conjunction with the accompanying drawing, in which:

Fig. 1 shows a perspective view of a gaseous discharge device constructed in accordance with the invention and having parts broken away to show internal construction;

Fig. 2 is a section taken on the line 2-2 of Fig. 1; and

Fig. 3 is a schematic diagram of a rectifying circuit employing a discharge device of the present invention.

Referring to the drawing, reference numeral Ill indicates an envelope of vitreous material containing an ionizable gas, for example, helium at a pressure of about fourteen millimeters of mercury. The tube is sealed at one end by an internal press II having a lead-in conductor I2 and supporting rods I3 for the cathode I4. Leadin conductors I5 connected to metal rods I6 provide lead-in conductors and supports for a, pa of auxiliary or starting electrodes II.

The other end of the tube is provided with a central conductor I8 sealed through the wall of the tube and providing a lead-in conductor and support for an anode I9 preferably of carbon. A metal sleeve 20, embedded in the seal, surrounds the anode I9 leaving a short clearance space therebetween. A glass sleeve 2I surrounding the anode I9 and its metal shield 20 is fused with the glass or other vitreous material of the envelope I0 and projects downwardly for a short distance below the end of the anode I9 and its surrounding sleeve 20. An end cap 22 of metal cemented around the central conductor I8 and electrically connected thereto is provided to protect the seal at the upper end of the tube, and also permits the connection of the anode to a suitable source of current.

The cathode I4 comprises a hollow tubular member preferably of nickel closed at its upper and lower ends by

end caps

23 and 24, respectively. An opening 25 is provided in the upper end cap 23 into which the sleeve 2I projects permitting a free discharge path between the anode I9 and the active interior surface of the cathode I4. The lower end cap 24 of the cathode I4 is provided with a pair of spaced openings through which the rods I6 project. The rods I6 extend upwardly through the cathode I4 to points adjacent to, but spaced from, the upper end cap 23. Glass sleeves 26 fused to the press II surround each of the rods I6 throughout the greater portion of their length terminating just below the upper ends thereof. Metal sleeves 21 surround the glass sleeves 26 throughout the portion of the length thereof within the cathode I4 and are rigidly secured to the cap 24 at the two openings therethrough. Preferably, a small clearance is provided between the metal sleeves 21 and the glass sleeves 26, and the upper ends of the metal sleeves 21 terminate flush with the ends of glass sleeves 26. Hollow iron wires H are welded to the projecting ends of the rods I6 and extend substantially at right angles thereto, projecting across the open end of sleeve 2I. The exposed ends of the rods I6 and the proiecting hollow iron wires II constitute auxiliary or starting electrodes having the iron wire portions II lying in or close to the same plane and extending approximately parallel, leaving a short gap between the parallel portions of the wires II. The distance across the gap between the 5 wires I1 is approximately equal to the minimum with regularly spaced apertures 30 through which the electron-emissive material is released.

A suitable circuit, in which the device disclosed in the foregoing may be applied, is shown in Fig. 3 in which the primary winding 3| of a transformer 32 is supplied with current from an alternating current source and stepped up to a voltage of the order of 1600 volts across the secondary winding 33. The anode I 9 of the tube is connected to one end .of the secondary winding 33 through a .peak current limiting resistor 34 which may be of the order of 10,000 ohms. The cathode i4 is connected to the opposite .end of the secondary winding 33 through a, condenser 35 which ,may

have a capacitance of the order of two microfar'ads. Oneof thestartin electrodes H is connected-to the anode through a resistor 31, the resistance of which is very high, for example, of the order of ten megohms. The other starting electrode 1 l is connected to theconductor between the secondary winding 33 and the condenser '35 through-a resistor 38 alsoof about ten megohms. A load resistor 36 which may be of the order of 200,000ohmsis connected across-the condenser 35. In operation, during the initial portion of the positive-half-wave of applied potential andbefore the initiation of conduction through the tube, one of the startingelectrodes l 'l will be at the same potential as the anode 1 9. The other starting electrode will be at the same potential as the negative side of the condenser 35. -At this instant, the glow discharge may be initiated between the two auxiliaryelectrodes H. The gas in the space immediately adjacent the anode l9 .in the spacebetween the anode l9 and'the cathode Icibcinghighly ionized, a glow discharge is now initiated between the anode l9 and the oathode ld. Upon .conduction through the anode- .cathode circuit of thetube, the potential between the two starting electrodes drops to a value incapable of supporting a discharge therebetween.

The spacingand arrangement of ,the two startingelectrodes insure that the starting'discharge 'across=the gap betweenthese twoelectrodes will occur, at leastin part, in the region adjacent the open end of the sleeve 2 I The-gasin-the region of the anode, aswellasthe gas in the interior of the cathode, is highly ionized byrthe-starting "discharge, thus insuring an immediate-discharge through the main electrodes.

- While there has been herein describedra-preferred embodiment ofthe invention, .iother'em- 'bo'dirnents within the scope of the appended claims 'will be apparent tothose skilled "fin' the --artfrom a' consideration of the' form shown .and

the teachings hereof.

What is claimed is:

l. A gaseous discharge device comprising an envelope containing an ionizable gas, a plurality of electrodes within said envelope, said electrodes including an anode, hollow cathode, and two starting electrodes, said anode being disposed exteriorly of said cathode and said cathode having an opening providing a discharge path between said anode and the interior of said cathode, said starting electrodes being mounted within said cathode and projecting across said opening, one

of said starting electrodes being an auxiliary cathode and the other a starting anode.

2. A gaseous discharge device comprising an envelope containing an ionizable gas, a plurality of electrodes within said envelope, said electrodes including an anode, a cathode, and two starting electrodes, said starting electrodes being mounted in the discharge path between said cathode and anode, said starting electrodes each including a hollow wire portion filled with electron .emissiye material and having spaced apertures, said wire portions being substantially parallel and spaced a distance from each other substantially t equal to the minimum breakdown-potential dis} tance.

v3. A gaseous discharge .device comprising an envelope containing an ionizable gas, a plurality .of electrodes within said envelope, said electrodes including an anode, a relatively large, hollow, metallic cathode, and two starting electrodes, said cathode having an opening providing a discharge path between said anode and the interior of said cathode, said starting .electrodes being mounted within said cathode and projecting across said opening, said starting electrodes including substantially parallel portions spaced-a distance from each other substantially equal to the breakdown-potential distance.

4. A gaseous discharge device comprising an envelope containing an ionizable gas, a plurality of electrodes-within said envelope, said electrodes including an anode, arelatively-large, hollow,metallic cathode, and two starting electrodes, said minimum cathode having an opening providingadischarge pathbetween said anode and the interior of said cathode, said starting electrodes being -mounted within said cathode and projecting across said opening, said starting electrodes each including transversely projecting wire portions, said wire portions being substantially parallel and spaced at distance from each other --substant,ially' equal to the minimum breakdown-potential distance.

5..A aseous discharge 'device comprising an envelope containing an ionizable gas, a plurality of electrodes within saidenvelope, said electrodes including. an anode,-;a, relatively large, hollow, me-

talliccathode, and two starting electrodes, said cathode having an opening providing a discharge path between said-anode and the interior of :said cathode, said starting electrodes being .monuted within said cathode and ,projecting across .said opening, said starting ,-electr,od es each including a hollowwire portion filled with-electron emissive material and having spaced apertures said .wire portions being substantially parallel and spaced 2. distance from each othersubstantially equal; to

the minimum breakdown-potentialdistance.

.6. A gaseous :discharge device comprising an envelope containin an-ion-izable .gas, aplurality of electrodes withinsaid envelope, said :electrodes including an anode, :a relatively'large,hollow, metallic cathode, andtwo starting electrodes, said cathode having an opening-providing ;adischarge path between. said anode and thepinterior of sa d cathode, an insulating sleeve surrounding said anode and having an open end projecting into said opening of said cathode, said starting electrodes being mounted within said cathode and projecting across said opening, said starting electrodes includin substantially parallel portions spaced a distance from each other substantially equal to the minimum breakdown-potential distance.

7. A gaseous discharge device comprising an envelope containing an ionizable gas, a plurality of electrodes within said envelope, said electrodes including an anode, a relatively large, hollow, metallic cathode, and two starting electrodes, said cathode having an opening providing a discharge path between said anode and the interior of said cathode, an insulating sleeve surrounding said anode and having an open end projecting into REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,722,588 Metcalf July 30, 1929 1,840,055 Rentschler Jan. 5, 1932 2,034,756 Hansell Mar. 24, 1936 2,276,861 Penney Mar. 17. 1942