US2039027A - Electric valve circuits - Google Patents

Description

L. F. FERRUTT zflgggm? ELECTRIC VALVE CIRCUITS Filed Oct. 6, 1954 Inventor: Lam ence TPerrott His AttOPfiC-By.

Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE ELECTRIC VALVE CIRCUITS New York Application October 6, 1934, Serial No. 747,164

9 Claims.

My invention relates to circuits for hot cathode electric discharge devices, and particularly to circuits including vapor electric valves.

In order to obtain the most satisfactory operation of hot cathode electric discharge devices and particularly vapor electric valves, it is necessary during the starting operation of these valves to allow the temperature of the cathode and the vapor pressure to reach a predetermined value before, the normal operating anode-cathode potential is applied. If the normal anode-cathode potential is applied before the vapor pressure and the temperature of the cathode reaches the proper value, much of the activating material of the cathode will be lost from its surface, resulting in a substantial reduction in the electron emitting properties of the cathode and, consequently, in a shortening of the life of the valve. This deleterious eifect is particularly noticeable in electric valves of the vapor electric discharge type which rely primarily for their operation upon the ionization of the contained vapor.

To secure adequate protection of the cathode during the starting period, it has been proposed to apply a reduced potential between the anode and the cathode during the starting period so that the voltage existing between the anode and cathode will be maintained below the values which result in the deleterious disintegration of the 0 cathode. As the vapor pressure and the temperature of the cathode rises, with a definite low voltage impressed between the anode and cathode, the current flowing through the valve will rise. The current which flows during this initial heat- 3 ing period may be used to indicate the vapor pressure and the temperature of the cathode.

When the conductivity of the tube increases to a suitable degree, the current thus flowing may be used to initiate the application of the normal operating voltage. Such an arrangement is disclosed and claimed in a copending application, Serial No. 507,906, entitled Electric valve circuits, filed by Alan S. Fitz- Gerald on January 10, 1931, and assigned to the same assignee as the present invention.

One object of my invention is to provide an improved apparatus for preventing excessive cathode disintegration.

50 Another object of my invention is to provide an improved apparatus for preventing excessive cathode disintegration of an electric discharge device by selecting the time of application of the normal operating potential to said device in ac- 5'5 cordance with the degree of conductivity of the discharge device and an electrical condition of the supply circuit therefor.

In accordance with my invention I provide means for applying a reduced voltage to a multianode vapor electric valve in order to allow the 5 vapor pressure and the temperature of the oathode to reach a predetermined value and for subsequently connecting the normal operating potentials to the anodes in response to various circuit conditions, one of which may be the degree 1 of conductivity of the valve. The desirability of apparatus of this nature is evident when it is considered that it is frequently necessary to assure that certain predetermined conditions be satisfied prior to the application of load to the valves. 15

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the single figure of the accompanying draw- 20 ing which is a diagrammatic representation of one embodiment of my invention I have shown an arrangement which is applicable to a multianode electric discharge device I having a pair of anodes 2, 3 and a cathode 4 which supplies a 5' direct current load circuit 5 with power obtained from an alternating current source 6 through a transformer l and an electromagnetic switching apparatus 8. The transformer l is provided with a primary winding 9, a winding [0 for supplying '0 energy to the discharge device I at a reduced potential, and windings ll, [2 with a neutral point l3, for supplying energy to the discharge device I at the normal operating potential.

The switching apparatus 8, which is shown as a unitary electromagnetic structure in the drawing, is provided with two pairs of stationary contacts l4, I5 and l6, IT. The lower pair of stationary contacts [4 and [5 are connected to the outside terminals of normal operating windings II and I2, respectively. One stationary contact l6 of the other pair is connected to an anode 3, and the other stationary contact I! is connected through a current coil [8 of the switching apparatus 8 to one terminal of the reduced voltage transformer winding II]. A bar l9, carrying contacts 20 and 2|, is slidably mounted upon a lower extension 22 of the core or armature 23 of the switching relay 8. The bar [9 is constructed to provide an electric circuit between contacts 20 and 2|. When the armature 23 is raised, due to the electromagnetic action of the current coil [8, it is apparent that the upper portion of extension 22 of the armature 23 will slide through a sleeve in bar l9 until the adjustable collar 24 mounted on the extension 22 of the armature engages the sleeve; thereafter the bar l9 will be raised, resulting in a separation of contacts 16, 20 and I1, 2|. Attached to the lower end of ex- -tension 22 are two movable contacts 25 and 25 which are insulated from each other and from extension 22 by a non-conductive member 26. These two contacts 25 and 25 are connected respectively to the anodes 2 and 3 through conductors 21 and 28 respectively. Flexible leads are provided to allow the contacts 25 and 25 to be moved vertically to engage the lower stationary contacts 14 and IS. A voltage responsive coil 29 is arranged to complete the raising of the armature 23 provided that a predetermined minimum voltage is present across the current source 6.

The operation of the apparatus may be best explained by first considering the condition of the apparatus prior to the energization of the supply circuit. It is apparent that prior to the energization of the input circuit 6, and immediately after the energization thereof, the connecting apparatus 8 is biased to connect the reduced potential winding ID to the anode 3 of valve I. At this point in the cycle of operation the circuit for supplying energy to the valve includes reduced potential transformer winding ID, the current responsive coil I8, contacts I! and 2|, bar l9, contacts l6 and 20, conductor 28, anode 3 and cathode 4.

Upon energization of the source 6, the cathode heating circuit 30 will also be energized. As the vapor pressure and the temperature of the oathode increase, with a definite reduced voltage from winding l0 applied to the anode 3 the current through the valve will rise. reaches a predetermined value the current responsive coil l8 will operate to raise the armature extension 22. If potentials above a predetermined potential obtain on alternating current source 6, the voltage responsive winding 29 will add to the effect produced by coil I8 and continue to raise the armature extension 22 to disconnect the starting circuit and connect the normal operatlng windings H and I2 to the anodes of the valve. By varying the position of collar 24 on the extension 22 of armature 23, it will be understood that the opening of the starting circuit and the connecting of the sources of normal potentials to the anodes, may be made to occur simultaneously or successively.

If the alternating current source does not maintain a potential above the predetermined minimum potential, it is evident that the movement upward of the armature will not be completed and the normal operating voltage will not be applied to the valve. In the particular embodiment shown in the drawing it is obvious that the switching apparatus 8 is concurrently responsive to the degree of conductivity of the valve I and to the potential of supply circuit 6. However, the connecting apparatus may be made responsive to any selected electrical condition of the translating circuit.

Upon deenergization of the supply circuit 6, the connecting apparatus will automatically return to its initial position. Upon subsequent reenergization the same sequence of operation will automatically follow.

To those skilled in the art it is obvious that a single or a plurality of single-anode valves can be used instead of the single multi-anode valve l shown in the figure. In the event that it is desirable to use two similar single anode valves, the cathodes of the valves will be merely connected When the current together, and the anode of one valve will be connected to contact 25' through conductor 28 and the anode of the other valve will be connected to contact 25 through conductor 21. It will be further evident that the coil 29 of connecting apparatus 8 may be made responsive to an electrical condition of any desired part of the translating circuit.

The apparatus described above automatically operates to apply a low potential to an electric discharge device, which may be either of the vacuum type or of the type containing an ionizable medium, until the device obtains a predetermined degree of conductivity and the apparatus then operates to apply the normal operating potential to the device if a predetermined electrical condition of the translating circuit is satisfied.

While I have described what I at present consider the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention, and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric translating circuit including an electric valve, a source of normal operating potential, a source of reduced potential initially connected to said valve, and unitary electromagnetic means responsive to a predetermined degree of conductivity of said valve and responsive to a predetermined electrical condition of said translating circuit for disconnecting said reduced potential and for connecting said source of normal operating potential to said valve.

2. In an electric translating circuit including an electric valve, a source of normal operating potential, a source of reduced potential initially connected to said valve, and unitary electromagnetic means responsive to a predetermined degree of conductivity of said valve and respon sive to a predetermined potential of said translating circuit for successively disconnecting said reduced potential and for connecting the source of normal operating potential to said valve.

3. In an electric translating circuit for connecting a supply circuit and a load circuit, an

electric valve provided with a plurality of anodes and a thermionic cathode, a source of reduced potential, a source of normal operating potential, and means responsive to a predetermined degree of conductivity of said valve and to potentials above a predetermined minimum potential of said supply circuit for initially connecting said source of reduced potential between one anode and said cathode and for subsequently connecting said source of normal potential to said anodes.

4. An electric valve apparatus for transmitting energy from an alternating current circuit to a direct current circuit including a transformer network provided with a source of normal operating anode-cathode potential and a source of reduced potential, a vapor electric valve provided with an anode and a cathode, a direct current load circuit connected between one terminal of said source of normal operating potential and said cathode, and unitary electromagnetic means determined minimum potential of said alternating current circuit for disconnecting said source of reduced potential from said anode and for connecting said source of normal potential to said anode.

5. An electric valve apparatus for transmitting energy from an alternating current circuit to a direct current circuit including a transformer network provided with a plurality of sources of normal operating potential, a neutral point and a source of reduced potential, a vapor electric valve provided with a plurality of anodes and a thermionic cathode, a direct current load circuit connected between the said transformer neutral point and said cathode, each of said anodes being associated with a predetermined one of said sources of normal potential, means for initially connecting said source of reduced potential between one anode and said cathode, and means responsive to a predetermined current through said valve and to a potential above a predetermined minimum potential of said alternating current circuit for disconnecting said reduced potential from said one anode and for connecting each of said sources of normal potential to its associated anode.

6. In an electric translating circuit, an electric valve, a source of normal operating potential, a source of reduced potential, means for selectively connecting said sourceof potential to said valve including means for initially connecting said source of reduced potential to said valve and an electro-responsive means comprising a winding responsive to a predetermined current through said valve and a voltage Winding responsive to a predetermined voltage of said translating circuit, and an armature actuated by said electro-responsive means for disconnecting said source of reduced potential from said valve and for connecting said source of normal operating potential to said valve.

'7. In an electric translating circuit, an electric valve, a source of normal operating potential, a source of reduced potential, switching means for initially connecting said source of reduced potential to said valve and for subsequently disconnecting said reduced potential, a second switching means for connecting said source of normal potential to said valve, an electro-responsive means comprising a current winding responsive to a predetermined current through said valve, and a voltage winding responsive to potentials above a predetermined minimum voltage of said translating circuit, an armature successively actuated by said current and voltage coils for actuating said switching means, and adjustable means associated with said armature for determining the time interval between the actuation of said several switching means.

8. In an electric translating circuit, an electric valve, a source of normal operating potential, a source of reduced potential, means for initially connecting said source of reduced potential to said valve and for subsequently disconnecting said source of reduced potential and connecting said source of normal potential to said valve, said means including an electro-responsive means comprising a current Winding responsive to a predetermined current through said valve, a voltage winding responsive to potentials above a predetermined minimum potential of said translating circuit and an armature having an initial position to effect application of the aforesaid source of reduced potential to said valve and a final position to effect disconnection of said reduced potential and application of said source of normal potential, said armature being adapted to be initiated in its movement by said current winding and moved to its final position by said current and voltage windings.

9. In an electric translating circuit, an electric valve, a source of normal operating potential, a source of reduced potential, means for selectively connecting said sources of potential to said valve, said means including an electro-responsive means comprising a current winding responsive to a predetermined current through said valve, a voltage winding responsive to potentials above a predetermined minimum potential of said translating circuit and an armature having an initial position to effect application of the aforesaid source of reduced potential to said valve, an intermediate position to efiect the disconnection of said source of reduced potential from said valve and a final position to efiect application of said source of normal potential, said armature being adapted to be moved from its initial position to its intermediate position by said current winding and to its final position by said voltage winding.

LAURENCE F. PERRO'I'I.

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