US2228210A

US2228210A - Gaseous relay device

Info

Publication number: US2228210A
Application number: US264705A
Authority: US
Inventors: Jr Robert Fred Hays
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1939-03-29
Filing date: 1939-03-29
Publication date: 1941-01-07
Anticipated expiration: 1958-01-07

Description

Jan. 7, 1941. R. F. HAYS, JR

GASEOUS RELAY DEVICE INVENTOR Filed March 29, 1959 Mm TTORNEY Patented Jan. 7, 1941- um'rso s'rA'rss zmsu Gaseous namv' nsvics 0cm .lastlitta Pa, a pony burgh, aeorporatien Application March as, use. Serial no. 264.165

3 Claims, (Cl. ass-21s 'lhepresentinventionrelatestoagaseouselectrio discharge device and more particularly to what may be termed a no-power-loss relay for makingandhreakinganelectriccircuit.

I Adevioeofthistylielsparticularlyadaptable whereithdesiredtomomentarilycloseacontrol circuit for initiailng the operation of numerous electrically operated apparatus. In the pending.

Serial No. 258,382, filed February 25,

1., 1939, of which I am a co-inventor, and which applicationisasignedtothesameassigneeas the present invention, a similar no-power-loss gaaeousrelayisshownand claimed andthe present inventim comfltutes an improvement there- 'l'he above noted application shows such gaseous relaydevieein conjunction with adischarge lamp to initiate a discharge between the thermioniedectrodesofthelamp. The relay tubeis cmmected to the filmamentary electrodes in' such manner as to connect the electrodes in series relationship to a suitable source of electrical energy of the customary commercial potential. Upon closure ofthe circuit a glow discharge moll' mentarllyoeeursinthegaseousrelaywhichheats theelectrodes,oneofwhichis abimetallic element, causing the electrodes to engage each other, thus the discharge and eiiecting a positive closure of the series circuit for the 80 filamentary electrodes of the discharge lamp allowing the latter to be heated to electron emitting temperature.

By the time the filamentary electrodes have reached electron emitting temperature the bias metallic electrodeofthegaseousrelay device will have cooled suiliclently to cause the electrodes tobecome Duetotheprovisionof an inductanceelementinseries with thedischarge lamp, a discharge is again initiated by the elec- Q trodes of the relay device separating. This produces a high transient voltage in the relay device, which voltage is impressed upon the electrodes ofthe discharge lamp, causing ionization of the gas therein, together with the initiation of a dis- 6 charge between the filamentary electrodes.

A high transient voltage alone, however, is insuillcient to cause ionimtion and the initiation of a discharge in the lamp as certain amount of energy is necessary. During momentary voltagesurgestheglowdischargeresultinginthe relay device upon separation of the electrodes has a positive volt-ampere characteristic. This high voltage thus causes the glow discharge to draw more current, somewhat in the same manas ner as is obtained by the'operation of an inductance elementinparalleiwitharesistance.

Moreover, for a given voltage the current drawn during the high transient voltage is proportional tothesurfaceareacltheelectrode and where Q the surface area of the electrode is comparatively large. in the'structure shown in the above mentioned application, too much. of the transient energy is consumed which should be available for the load or discharge lamp in order to facilitate more rapid starting. I

It is accordingly an object of the present invention to provide a gaseous relay tube wherein' the current drawn by the device during high transient voltages is maintained low.

Anotherobiect oi the present invention is the 10 provision of a gaseous relay device which during operation has a high eilective resistance to permit high transient voltagu with very small current consumption during the formation of a discharge.

Another object of the present invention is the ll provision of a gaseous relay device having electrodes of widely diifering surface area which results inlow energy consumption at high transient voltages.

A further object of the present invention is M the provision of a gaseous relay device having electrodes of widely diflering surface area and a gaseous atmosphere within a preselected pressure range so that a glow discharge is originally initiated at'alow voltage and subsequently a 2 high transient voltage at low current passes through the device for supplv ns a load.

Still further objects of the present invention willbecome obvioustothoeeskiiledinthe art by reference .:to the accompanying drawing 30 wherein: I

Fig. l is a diagrammatic illustration of an electrical circuit for energizing a load such as a discharge lamp and wherein the gaseous relay device of the present invention is utilized to con- 35 trol the circuit;

Fig. 2 is a fragmentary view inperspective of the gaseous relay device of the present invention;

Fig. 3 is a plan view of the relay device as shown in Fig. 2, and Y Fig. 4 is a fragmentary view in perspective of a modification which the gaseous relay device of the present invention may take.

Referring now to the drawing in detail, a circuit is shown in Fig. '1 for starting a gaseous 4g discharge lamp and illustrates one specific use for which the gaseous electric discharge relay device of the present invention may be employed. The gaseous discharge lamp 5 as shown in Fig. l is provided with oppositely disposed filamentary electrodes I and l of a refractory metal, such as tungsten or the like, which may be in the form oi a coiled coil coated with an electron anissive material, such as an oxide of barium, strontium, or the like, to provide a copious flow of electrons 5 when heated.

After evacuation the lamp is filled with a rare gas to facilitate starting, towhichis added a few drops of mercury, as is well known in the art. One terminal of the electrode 8 is connected 0 by a conductor I through an inductance element 9 to one side of the source of supply of the customary domestic potential of 115 or 330 volts. Likewise, one terminal of the electrode I is connected by a conductor II and switch ii to the opposite side of the domestic source of supply. The remaining terminal of each electrode is connected through the medium of a gaseous electric discharge relay device II so that upon closure of the relay contacts, the electrodes 0 and I are initially in series with each other and the source of supply, thus heating the electrodes to an electron emitting temperature.

When the temperature of the electrodes reaches a value suflicient to cause a copious flow of electrons, the relay device It automatically operates to interrupt the series heating circuit for the electrodes. The attendant voltage increase, upon operation of the device ll, causes a discharge between the electrodes 6 and I with the result that the discharge carries the current and the voltage across the electrodes of the device I! is too low to start a discharge therebetween until extinguishment of the discharge between the electrodes 6 and 1 of the lamp 8.

Except for the construction of the gaseous electric relay device ii, the circuit of Fig. l in no way differs from that shown and described in the above identified copending application. Since the device of the present invention may be employed in conjunction with any circuit where a sequential operation of the various elements of a given system is desired, Fig. 1 serves merely as llustrative and further description thereof is believed unnecessary.

The gaseous electric relay device I 3 as shown in Fig. 1 comprises an envelope which after evacuation is filled with an ionizable medium. such as neon or the like, at a pressure below approximately 30 millimeters, depending upon the particular line voltage and at the voltage of the customary commercial source of 115 volts, the pressure approximates 15 millimeters. The device is provided with any suitable type base I and, as shown more clearly in Figs. 2 and 4, it has a reentrant press portion it provided with an exhaust stem ii, as customarily employed in the fabrication of incandescent la ps.

A pair of leading-in and supporting conductors l1 and II are sealed into the reentrant press and interiorly of the envelope an electrode ll of suitable refractory metal, such as tungsten in the form of a wire or rod, is welded to the extremity of the leading-in and supporting conductor I! which extends substantially transversely to the longitudinal axis of the device I! or may be parallel to such axis, as shown in Fig. 4. In a similar manner, a U-shaped bimetallic electrode 2. of appreciably greater surface area is secured to the leading-in and supporting conductor II which likewise extends transversely of the longitudinal axis of the device It or may be parallel therewith, as shown in the modification of Fig. 4.

This latter electrode II is provided with a contact terminal 22 of refractory metal, such as tungsten, and a coating or a small piece of material 23, such as magnesium or the like, is secured to the surface of the bimetallic electrode 20 which emits a copious flow of electrons.

Upon the application of a potential of approximately 115 volts from the customary commercial source to the electrodes I! and 2., a glow discharge occurs due to the emission of electrons from the coating or strip of magnesium 23 carried by the electrode 20 when functioning as cathode. These electrons cause ionization of the gaseous medium. with the result that the glow discharge at this low voltage of 115 volts occurs between the electrode 2| serving as cathode and the electrode l9 functioning as anode during one half wave of the alternating current cycle. This ensuing discharge heats the bimetallic electrode or cathode 2| causing deflection thereof, as shown in dotted lines in Fig. 2, until the refractory metal contact terminal 22 engages the electrode It, thus short-circuiting the electrodes and extinguishing the discharge.

The circuit controlled by the relay device ll accordingly receives current due to the positive engagement of the electrodes ll and 2.. During this period of current flow, however, the bimetallic electrode 2| cools suiliciently to cause it to again deflect to its original position and in separating the glow discharge is re-established and an arc-like discharge is initiated between the points of contact. At the same time a high transient voltage of approximately 600 to 1800 volts is produced by the inductive voltage "kick" of the inductance 0 (Fig. 1) which is impressed upon the load or lamp I, as well as upon the relay.

In order for the relay device to allow the inductance to produce such high transient voltages, its effective resistance must be high. The inductance forces current to flow for an instant after separation of the electrodes I! and 2. and the transient voltage is equal to the product of the current at the instant of disengagement of the electrodes and the elective resistance of the relay device. The effective resistance of the device is composed of the resistance of the glow discharge in parallel with the resistance of the arelike discharge which is established between the electrodes as they separate. Reducing the surface area of one electrode to a minimmn increases the resistance of the glow discharge to a maximum for the half cycles of alternating current during which that electrode serves as cathode.

The resistance of the arc-like discharge between the electrodes may be increased by decreasing the pressure of the filling gas below 30 mm. of mercury, but at the same time the pressure must not be decreased below a value at which a glow discharge canbe initiated at the line voltage, although it should be noted that the higher the line voltage, the lower the pres sure may be. This is because the mean free path is so great that insufiicient atoms of gas are between the points of contact of the electrodes which part last during separation thereof to enable the arc-like discharge to conduct appreciable current and because at lower pressures considerable time is required for the ionization of the gas to build up thereby increasing the resistance of the device during the moment of application of the high transient voltage. High effective resistance of the relay device not only results in higher transient voltages, but also causes a greater portion of the transient current to be diverted from the relay device through the load or discharge lamp for the purpose of establishing the discharge.

It thus becomes obvious to those skilled in the art that a gaseous relay device is herein shown and described for controlling a circuit to a load which initiates a glow discharge upon the application of a voltage thereto from the customary commercial source of approximately 115 volts, and such discharge heats at least one of the electrodes to cause it to be deflected into engagement with the other electrode and extinguish velope provided with an iouizable medium therethe glow discharge. Upon cooling the electrode and its deflection back to normal position, an arc-like discharge is initiated. a result of the high transient voltage. electrodes of comparatively wide variation in surface area wherein the area of oneelectrode is not greater than fifty per cent and preferably much less than the area of the other electrode,

the relay device has a high eifective resistance and low current consumption so that substantially no power is lost, which is thus available for the load.

Although two embodiments of the present invention have been shown and described, it is to be understood that still further modifications of the present invention may be made without departing from the spirit and scope of the appended claims.

What is claimed is:

l. A gaseous electric device comprising an envelope provided with an ionizable medium therein and a pair of electrodes, one of which is a thermo-expansive electrode adapted to emit elec-- trons to cause a glow dmcharge between said electrodes thereby heating said thermo-expansive electrode with attendant movement thereof into contact with the other of said electroda to short-circuit the same and extinguish said discharge and said thermo-expansive electrode being movable away from said other electrode upon cooling, and the other of said electrodes having a surface area substantially less than the area of said thermo-expansive electrode to increase the transient voltage between the electrodes at the instant of separation thereof.

2. A gaseous electric relay device comprising an envelope provided with a pair of electrodes and an ionizable medium therein at a pressure below 30 millimeters of mercury, one of said electrodes being a theme-expansive electrode provided with an electron emissive material adapted to emit a copious flow of electrons to cause a discharge between said electrodes thereby heating said thermo-expanslve electrode with attendant deflection thereof into contact with the other of said electrodes to short-circuit the same and extinguish said discharge, and the other of said electrodes being of substantially smaller area for the purpose of increasing the effective resistance of said device to thereby increase the transient voltage between the electrodes and to limit the current consumption at the instant of separation of the electrodes upon cooling of said thermo-expansive electrode.

3. A gaseous electric device comprising an envelope provided with an ionizable medium therein, a pair of electrodes in said envelope, one of said electrodes being a thermo-expansive electrode provided with an electron emissive mate rial adapted to emit electrons and movable toward said other electrode when heated by the discharge between said electrodes to short-circuit the latter and extinguish said discharge and movable away from said other electrode upon cooling, and the other of said electrodes having a small area compared to that of the thermo-expansive electrode to increase the transient voltage between the electrodes at the instant of separation thereof upon cooling of said thermo-expensive electrode.

4. A gaseous electric device comprising an en- Moreover. by employing in, a pair of electrodes in said envelope, one of said electrodes being a bimetallic element adaptedtoemitelectmnstocauseaglowdischarge between said electrodes thereby heating said bimetallic electrode with attendant movement thereof toward said other electrode into engagement therewith to extinguish said discharge and movable away from said other electrode upon cooling, andthe other of said electrodes having an area substantially less than that of said bimetallic electrode to increase the transient voltage between said electrodes at the instant of separation thereof upon cooling of said bimetallic electrode.

5. A gaseous electric device comprising an envelope provided with an ionizable medium therein, leading-in conductors extending through said envelope, and a pair of electrodes connected to said leading-in-conductors and disposed interiorly of said envelope, one of said electrodes being a bimetallic electrode bent upon itself with its free end disposed adjacent the other of said electrodes and provided with an electron emissive material adapted to emit a copious flow of electrons to cause a glow discharge between said electrodes and heating of said bimetallic electrode with attendant deflection thereof into contact with the other of said electrodes to shortcircuit the same and extinguish said discharge, and the other of said electrodes having a surface area less than one-half the area of said bimetallic electrode.

6. A gaseous electric device comprising an envelope provided with an ioniaable medium therein, a pair of electrodes in said envelope, one of said electrodes being a U-shaped bimetallic element provided with an electron emissive material and having its free end disposed adjacent the other of said electrodes to cause a glow discharge between said electrodes and heating of said bimetallic electrode with attendant deflection thereof into contact with the other of said electrodes.

7. A gaseous electric relay device comprising an envelope provided with an ionizable medium therein, a pair of electrodes in said envelope, one of said electrodes beinga U-shaped bimetallic element with its free end disposed adjacent the other of said electrodes and provided with an electron emissive material adapted to emit a copious flow of electrons when heated to cause a glow discharge between said electrodes and heating of said bimetallic electrode with attendant deflection thereof into contact with the other of said electrodes, and the other of said electrodes being of rod-like configuration.

8. A gaseous electric device comprising an envelope provided with an ionizable medium therein, a pair of electrodes in said envelope, one of said electrodes being a U-shaped bimetallic element provided with an electron emissive material adapted to emit a copious flow of electrons when heated, and a contact terminal carried by the free end of said bimetallic electrode adjacent the other of said electrodes and engageable therewith upon the application of a potential between said electrodes and the occurrence of an ensuing discharge with attendant heating and deflection of said bimetallic electrode.

ROBERT FRED HAYS, JR.

Disclaimer 2,228,210.R0bert Fred Hays, Jr., Bloomfield, N. J. GABEQUS RELAY Dmcz. Patent dated Jan. 7, 1941. Disclaimer filed June 14, 1951, by the assignee, Westinghouse Electric Carpomtion. Hereby enters this disclaimer to claims 1,- 2, 3, 4, 5, 6, and 7 of said patent.

[Oyficial Gazette July 10, 1.951.]

DiscIaimer 2,228,210.-R0bert Fred Hays, Jr., B1001 nfie1d, N. J. GASEQUS RELAY DEVICE. Patent dated Jan. 7, 1941. Dlsclaimer filed June 14, 1951, by the assignge, Westinghouse Electric Corporation. Hereby enters this disclaimer to claims 1,- 2, 3, 4, 5, 6, and 7 of said patent.

[Oyfiozal Gazefie July 10 1951.]