US2232002A - Gaseous electric relay device - Google Patents

Description

Feb. 18, 1941. HAYS, JR

GASEOUS ELECTRIC RELAY DEVICE Filed Jan. 26, 1939 INVENTOR E. Ff H/i YJJ/T mu \Amn.

ATTORNEY Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE GASEOUS ELEC'IBIC RELAY DEVICE Pennsyl Application January 26, 1939, Serial No. 252,875

5 Claims. (01. 250-275) The present invention relates to a gaseous electric discharge device and more particularly to what may be termed a no-power-loss relay operable to make and break an electric circuit.

A device of this type has a diversity of uses. such for example as a starting relay for a discharge lamp wherein thermionic cathodes are employed which are connected in series to a suitable source of electrical energy for the purpose of heating the electrodes to an electron emitting temperature and initiating a discharge therebetween. after which the series circuit is interrupted by the relay, as shown and described in the copending application of E. C. Dench, Serial No. 242,927,

' filed November 29, 1938, and assigned to the same cuits it is highly desirable in many instances that the relay which operates to open and close the circuit consume no power so that the emciency of the entire system, whether supplying a lamp or other load, may be enhanced. Moreover, the relay must operate with fidelity and be positive in its function, otherwise the apparatus controlled by the relay tube may be materially damaged.

It is accordingly an object of the present invention to provide a gaseous electric discharge relay device which is positive in its operation and which consumes no power from the system in which such device is incorporated so that the efllciency of the system is increased.

Another object of the present invention is th provision of a gaseous electric relay device wherein a pair of electrodes are employed and comprising a bimetallic element which is heated by the ensuing discharge between the electrodes so that the electrodes are short-circuited after operation of the discharge for a brief interval of time, causing extinguishment of the discharge and without such relay device consuming any power from the system in which the device is incorporated.

Another object of the present invention is the provision of a gaseous electric discharge device comprising a pair of electrodes including a bimetallic element provided with an electron emissive coating and between which a discharge occurs upon the application of a suitable potential to the electrodes so that after a brief interval of time the bimetallic element is heated by the discharge to cause engagement of the electrodes with attendant short-circuiting oi the discharge and its extinguishment, and wherein a material which evolves an electron emissive material is provided for replenishing the coating on the bimetallic element during operation of the device, with the device consuming no energy from the circuit in which it is incorporated.v

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawing wherein:

Fig. 1 is a schematic illustration of a circuit for a discharge lamp employinga gaseous electric discharge relay device in accordance with the present invention;

Fig. 2 is an elevational view of the gaseous electric discharge device of the present invention partly in cross-section and with parts broken away to better illustrate the various parts of the device, and

Fig. 3 is a cross-sectional view taken on the line IIII1I of Fig. 2. a

Referring now to the drawing in detail, a circuit is shown in Fig. 1 for starting a gaseous electric discharge lamp and illustrates one specific use for which the gaseous electric discharge relay device of the present invention may be employed. In Fig. 1 the gaseous electric discharge lamp 5 is shown provided with oppositely disposed filamentary electrodes 6 and I of a refractory metal, such as tungsten or the like, which may be in the form of a coiled coil coated with an electron emissive material, such as an oxide of barium, strontium, or the like, to provide a copious flow of electrons when heated.

After evacuation the lamp is filled with a rare gas at a few millimeters pressure to facilitate starting to which is added a few drops of mercury, as is well known in the art. One terminal of the electrode 6 is connected by a conductor 8 through an inductance element 9 to one side of the source of supply of the customary domestic potential of or 230 volts. Likewise, one terminal of the electrode 1 is connected by a conductor l0 and switch I2 to the opposite side of the domestic source of supply.

The remaining terminal of each electrode is connected together through the medium of a gaseous electric discharge relay device i3 so that upon closure of the relay contacts the electrodes 6 and I are initially in series with each other and the source or supply, thus heating the electrodes to an electron emitting temperature. When the temperature of the electrodes reaches a value sufiioient to cause a copious flow of electrons, the relay device i3 automatically operates to interrupt the series heating circuit for the electrodes. The attendant voltage increase, upon operation of the device l3, causes a discharge between the electrodes 6 and I with the result that this discharge carries the current, and the voltage across the electrodes of the device i3 is too low to start a discharge therebetween until extinguishment oi the discharge between the electrodes 6 and 1.

Except for the construction and operation of the relay device I3, the circuit of Fig. 1 as just described is well known in the art. Since the circult per se forms no part of the present invention, but serves merely to illustrate one type of circuit in which the relay device of the present invention maybe incorporated, further detailed description thereof is believed unnecessary. It should suilice to say that the relay device l3 may be readily employed in a circuit of this type. as well as many other types of control circuits wherein a sequential operation of various elements of a given system is desired.

Referring now more particularly to Fig. 2, the relay device 13 as shown comprises an evacuated envelope H which, after evacuation, is filled with an ionizable medium, such as neon or the like, and provided with a reentrant press portion l5. Secured to the envelope is a suitable type base, such for example as a threaded base ii at the type customarlly employed in incandescent lamps.

A pair or leading-in and supporting conductors l1 and i8 extend from the base Ii to the interior of the envelope I 4, being sealed to the reentrant press portion I5. The leading-in and supporting conductor I! has rigidly secured to the end thereof, such as by welding or the like IS, a bimetallic electrode 2| of substantially semi-annular shape and disposed in a horizontal plane, which electrode may carry at its free end a contact terminal 01' silver or the like 22.

The bimetallic electrode 20 is provided with a coating or electron emissive material 23, such as a coating of alkaline earth metals, which gives off a copious flow of electrons when heated. Also secured to the leading-in conductor ll, such as by welding or the like 24, is a substantially spiralshaped metallic electrode 25 0t molybdenum or the like having a tangentially extending portion 2|, the free end or which terminates in juxtaposition to the contact member 22 carried by the electrode 2|.

As will be noted in Fig. 2, the leading-in conductor l| above the connection of the metallic electrode 25 thereto is bent normal to the longitudinal axis of the relay device l3, and to this transversely disposed portion 21 a. member is secured which houses a material which evolves electron emisslve material for replenishing the coating 23 on the bimetallic electrode 2| during operation of the device, as hereinafter more fully described. Thismemberasshowncomprisesa screen 2|, such as nickel or the like, welded or otherwise secured to the transversely extending 'portion 21 of the leading-in conductor II. A

dome-shaped metallic shield 29, which may be of the same material as the screen 2|, has its periphery welded or otherwise secured to the screen 2|, and in the concave portion of such shield, and weldedorotherwisesecuredtothescreen 2|as wellastothetransverselyextendingportion 21 of the leading-in conductor II, is a plurality of small rods 3|.

These rods are formed 01 magnesium or other material which, when heated, evolves electron emisslve material. The shield 29 prevents the evolved electron emimive material from passing in any direction other than through the openings in the screen 2| toward the bimetallic electrode 2| so that during operation or the device this coating is continually replenished Upon the applicaton ot a suitable potential to the gaseous electric discharge relay device it, the electrons will be emitted by the coating 28 on the bimetallic electrode 2| when functioning as cathode. These electrons will cause ionization of the neon or other gas within the device, with the result that a discharge occurs between the electrode 20 and the electrode 25, functioning as anode. The ensuing discharge accordingly heats the bimetallic electrode or cathode 2|, causing expansion of the latter until the contact terminal 22 carried by the end thereof engages the tangentially extending portion 2| of the anode electrode 25, thus short-circuiting the electrodes and extinguishlng the discharge.

Accordingly, the initial how 0! current in the circuit in which the relay device I3 is incorporated is by virtue of the ensuing discharge; but even after extinguishment of the latter, the current will continue to fiow due to positive engagement of the electrodes 2| and 25. However, extinguishment of the discharge by short-circuiting oi the electrodes then causes the bimetallic electrode 2| to cool and contract, thus interrupting the engagement thereof with the electrode 25 and conditioning the relay device I! for repetition oi its operation.

Inacircuitsuch asshowninFig. 1 adischarge does not again occur in the relay device It, since the current in the circuit fiowsby virtue-o! the resulting discharge between the electrodes i and 1 of the lamp 5: and in a similar circuit wherein some load other than a discharge lamp is energized, the same electrical phenomena will follow. It the current flow in the circuit is not bi-passed in a manner similar to that just mentioned with respect to the circuit 0! Fig. 1, such for example as where the relay device I2, is employed to periodically energize a load. a discharge in the relay device I! will ensue following disengagement oi the electrodes until the bimetallic electrode is again heated to cause casement or the electrodes, which cycle at operation continues so long asdaz'potentlal is applied to the electrodes 2| an Moreover, due to the substantially semi-annular configuration of the bimetallic electrode 2| and the spiral configuration of the electrode 25, together with the tangentially extending portion 26, these electrodes are resilient and thus yieldable in a common horizontal plane so that no distortion or the electrodes results either during operation or seasoning of the electrodes due to heating during the exhaust step of fabrication.

Since the rods 2|, consisting of a material which evolves an electronemissivematerial, are electrically and mechanically connected to the same leading-in conductoras the electrode 25 and thus at the same instantaneous polarity as such The discharge accordingly heats the rods of the material 2| causing the evolvement of the magnesium or other material which sputters tion and which consumes no power from the system in which it is incorporated so that the efficiency 01 such system is increased. Moreover, inasmuch as the electrodes are resilient and yieldable in a common plane, they are not distorted during fabrication or operation of the device, nor by changes in ambient temperature and wherein a bimetallic element in the form of an electrode is provided which is heated by the ensuing discharge to cause engagement of the electrodes and extinguishment of the discharge together with positive closure of the circuit controlled by such device.

Shortly following extinguishment of the device, the bimetallic electrode cools to open up the engagement of the electrodes, thus conditioning the relay device for repetition of its cycle of operation, which operation is dependent upon the particular arrangement of the circuit so that repetition may instantly follow or may be deierred until the occurrence of some other phenomena in the controlled circuit.

It should also be noted that while in the preferred embodiment of the present invention the bimetallic element itself is utilized as an electrode, it is to be understood that fixed electrodes may be employed with the bimetallic element connected to one of the electrodes and positioned adjacent the ensuing discharge so as to be heated thereby. Upon heating of the bimetallic elec- Y trode it then flexes to contact the other electrode or leading-in conductor therefor and extinguishes the discharge in the same manner as above described where the bimetallic element is utilized as one of the electrodes.

Although one specific embodiment of the presv ent invention has been shown and described, it is to be understood that other modifications thereof may be made without departing irom the 40 spirit and scope of the appended claims.

I claim:

1. A gaseous electric discharge device comprising a container provided with an ionizable medium therein and having resilient electrodes yieldable in a common plane and between which by the ensuing the ensuing discharge o prising g5 shaped bimetallic 7o shaped electrode a discharge occurs upon application 01! a suitable potential thereto, and one of said electrodes being a bimetallic element provided with an electron emissive coating and adapted to be heated discharge and operable to shortcircuit said electrodes and extinguish said discharge, and means disposed interiorly or said container and independent of the electron emissive coating on said electrode and responsive to between the electrodes for replenishing the electron emissive coating on said bimetallic element during operation of said device.

2. A gaseous electric discharge device coma container provided with an ionizable medium therein and having a substantially spiralshaped electrode provided with a tangentially extending portion to render said electrode yielda-' ble in a predetermined plane, a semi-annular electrode substantially surrounding said spiral-shaped electrode and yieldable in the same plane as the latter with an end terminating in juxtaposition to the end 0! the tangentially extending portion or said spiraland provided with a coating of electron emissive material on its surface for causing a discharge between said electrodes up n the application oi a suitable potential thereto, and

said bimetallic electrode being adapted to be heated by the ensuing discharge and operable to short-circuit said electrodes and extinguish said discharge.

3. A gaseous electric discharge device comprising a container provided with an ionizable medium therein and having resilient electrodes yieldable in a common plane and between which a discharge occurs upon application of a suitable'potential thereto, one of said electrodes comprising a bimetallic electron emitting coating and adapted to be heated by the ensuing discharge and operable to short-circuit said electrodes and extinguish said discharge, and a member connected to the other of said electrodes and disposed 'in juxtaposition to the bimetallic electrode and containing an electron emissive material which replenishes the coating on said bimetallic electrode during operation of said device by the action of the discharge on the material contained in said member.

4. A gaseous electric discharge device comprising a container provided with an an ionizable medium therein and having resilient electrodes yieldable in a common plane and between which a discharge occurs upon application of a suitable potential thereto, one of said electrodes comprising a bimetallic element provided with an electron emitting coating and adapted to be heated by the ensuing discharge and operable to short-circuit said electrodes and extinguish said discharge, a material which evolves an electron emitting material electrically and mechanically connected to the other of said electrodes and disposed in juxtaposition to the bimetallic electrode for replenishing the electron emissive coating on the latter by deposition during operation or said device by the action of the discharge on said material, and said material for preventing the passage of electron emissive material except in the direction of said bimetallic electrode.

5. A gaseous electric discharge device comprising a container provided with an ionizable medium therein and having a substantially spiral-shaped electrode provided with a tangentially extending portion to render said electrode yieldable in a predetermined plane, a semi-annular shaped bimetallic electrode substantially surrounding said spiral-shaped electrode and yieldablein the same plane as the latter with an end terminating in juxtaposition to the end of the tangentially extending portion of said spiralshaped electrode and provided with a coating of electron emissive material on its surface for causing a. discharge between said electrodes upon the application of a suitable potential thereto, said bimetallic electrode being adapted to be heated by the ensuing discharge and operable to contact the other or said electrodes to extinguish said discharge, a material which evolves an electron emitting material electrically connected-to said spiral-shaped electrode and disposed in juxtaposition to the bimetallic electrode for replenishing the electron emissive coating on the latter by deposition during operation or said device by the action of the discharge on said material, and a shield partially surrounding said material for preventing the passage of evolved electron emissive material except in the direcelement provided with an a shield partially surrounding

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