US2167498A - Electric valve circuit - Google Patents

Description

July 25, 1939. o. E. CHAMBERS 2,157,498

ELECTRIC VALVE CIRCUIT Filed March 29, 1958 Inventor Dudleg 15. Chambers,

S Attorney.

Patented July 25, 1939 UNITED STATES PATENT OFFICE ELECTRIC VALVE CIRCUIT New York Application March 29,

6 Claims.

My invention relates to electric valve circuits and more particularly to control circuits for electric valve means of the type employing ironizable mediums such as gases or vapors.

More specifically, my invention relates to improvements in circuits of the nature disclosed and claimed in United States Letters Patent No. 2,104,633, granted January 4, 1938, upon an application of E. F. W. Alexanderson, and which 10 is assigned to the assignee of the present application.

In electric valve circuits which employ a plurality of individual arc discharge paths, it has been found that the continuous rating of the electric valve group may be increased by utilizing the substantially greater short-time or monetary current ratings of the individual arc discharge paths. Particularly in connection with electric valve means of the type employing mercury pool 9,!) cathodes and immersion-ignitor control members, it has become apparent that it is highly desirable to utilize the larger short-time or momentary current ratings of the individual arc discharge paths by causing the paths to conduct current in a predetermined order or in a predetermined sequence. By the term immersion-ignitor control member is meant that type of control member which has an extremity thereof immersed below the surface of the mercury pool cathode and .30 which is of a material having a specific electrical resistivity substantially greater than that of the associated mercury pool cathode. It has been found that an immersion-ignitor or make-alive type control members may be constructed of a material such as boron-carbide or silicon-carbide,

of a material such as that disclosed and claimed in United States Letters Patent No. 1,822,742, granted September 8, 1931, on an application of Karl B. McEachrcn and assigned to the assignee of the present application.

Where a number of electric valves are connected in parallel relation to conduct current in the same direction and Where it is desirable to increase the continuous current rating of the electric valve group by causing the valves to conduct current in a predetermined order, it has been found important to employ controlling means which assure that one of the'ccntrol members of the electric valves is always connected to the source which energizes the control members.

It is an object of my invention to provide a new and improved electric valve circuit.

It is another object of my invention to provide a new and improved excitation system for electric valve apparatus,

1938, Serial No. 198,656

It is a further object of my invention to provide a new and improved arrangement for increasing the continuous rating of electric valve means which employ mercury pool cathodes and associated immersion-ignitor type control members.

In accordance with the illustrated embodiment of my invention, I provide an improved electric valve circuit for energizing a load circuit, such as a welding circuit, from an alternating current supply circuit through electric valve apparatus of the type employing an ironizable medium and which includes two pairs of parallel-connected arc discharge paths, the respective pairs of are discharge paths being oppositely connected relative to each other but the individual discharge paths of each pair being connected to conduct current in the same direction. The continuous current rating of the respective valve groups is sub-stantially increased by causing the arc discharge paths to conduct current alternately to utilize the substantially greater short-time or momentary current ratings of the valves. The immersion-ignitor control members are energized from an excitation circuit which is energized in accordance with the anode-cathode voltage of the discharge paths and includes an electric valve of the controlled type which effects ener gization of the control members in accordance with a periodic control voltage which is generated by a separate timing circuit. In order to assure that one of the immersion-ignitor control members is always connected to the excitation circuit, I provide an improved switching device which includes pairs of overlapping contacts having periods of simultaneous closure. The switching device is provided with an actuating coil which is periodically energized to eifect alternate energization of the control members of the electric valves in each group to cause the respective arc discharge paths to conduct current alternately. A pair of relays is employed to effect the periodic energization of the actuating coil of the switching device, one of the relays controlling the energization of the actuating coil and the other relay being responsive to the operation of the first relay to efiect periodic operation thereof.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims. The singe figure of the accompanying drawing diagrammatically illustrates an embodiment of my invention as applied to an electric valve system for energizing a welding circuit.

III

Referring now to the single figure of the drawing, my invention is diagrammatically illustrated as applied to an electric valve translating circuit for energizing a load circuit I, such as a welding circuit, from an alternating current supply circuit 2. Energy is transmitted to the welding circuit I through a transformer 3 and through two groups 4 and 5 of electric valves. If desired, a suitable circuit controlling means, such as a switch 6, may be interposed between the supply circuit I and the translating apparatus. The groups of electric valves 4 and 5 are reversely connected in parallel so that these groups are capable of transmitting alternating current to the welding circuit I. Each group 4 and 5 includes a plurality, such as a pair, of electric valve means I and 8. Electric valve means I and 8 are preferably of the type employing an ionizable medium, such as a gas or a vapor, and each includes an arc discharge path comprising an anode 9, a cathode I 9 which may be of the self-reconstructing type such as a mercury pool cathode, and an immersion-ignitor control member II having an extremity thereof extending below the surface of the associated mercury pool cathode. The electric valves I and 8 in groups 4 and 5 are connected to conduct current in the same direction, and have corresponding electrodes connected across the same points of potential difference in the electric translating circuit.

I provide excitation circuits I2 and I3 which are associated with the groups 4 and 5 of the electric valves, respectively, to effect energization of the respective associated control members II. The excitation circuits I2 and I3 are connected to be energized in accordance with the respective anode-cathode voltages of the groups of valves and each includes an electric valve I4 which is preferably of the type employing an ionizing medium, such as a gas or a vapor, and each includes an anode I5, a cathode I6 and a control member or grid IT. A suitable current responsive and protective means, such as a fuse I8 and a current limiting resistance I9, may be connected in series relation with each of the electric valves I4. In order to obtain a negative unidirectional biasing potential to maintain the control electric valves I4 nonconductive except during those intervals when it is desired to energize the associated control members II of electric valves I and 8, I employ any suitable means such as rectifiers 20, which may be energized from the alternating current circuit 2 and may include a transformer 2| and a pair of unidirectional conducting devices such as electric valves 22. The rectifier 29 associated with each excitation circuit establishes a negative unidirectional voltage across a suitable circuit, such as a parallel connected resistance 23 and a capacitance 24. A capacitance 25 may be connected across the cathode I6 and grid II of the control electric valve I4 in each of the excitation circuits to absorb transient voltages which may be present in the circuits. As a means for introducing into the excitation circuit I2 a periodic voltage or an impulse of voltage to render the associated control valve I4 conductive at the desired time and during predetermined intervals, I provide a resistance 26 which is energized by a timing circuit described hereinafter.

In the arrangement shown in the figure, the electric valves I and 8 of group 5 are shown as being arranged to follow the electric valves I and 8 of group 4. This is accomplished by employing excitation circuit I3 which is responsive to the energization of the load circuit I by means of the electric valves 1 and 8 of group 4. When the load circuit I is energized, control electric valve I4 of excitation circuit I3 is rendered conductive by a voltage appearing across a capacitance I3 which is connected in series relation with the control member of this valve. The capacitance I3 is energized in response to the energization of the transformer 3 by means of a transformer I3 which is connected across the primary winding of transformer 3. Certain features of this type of control, involving leading and trailing electric valves, are disclosed and claimed in United States Reissue Patent No. 20,335, granted April 20, 1937, on an application of Harold W. Lord and which is assigned to the assignee of the present application.

As an agency for producing a periodic voltage for effecting periodic energization of the load circuit I, as for example in line or seam Welding operations, I employ a timing circuit 21. The timing circuit 21 transmits impulses of current through resistance 26 in excitation circuit I2 to render the control electric valve I4 conductive periodically and hence render the electric valves 1 and 8 in groups 4 and 5 conductive during corresponding intervals. The timing circuit 21 includes a source of unidirectional voltage com prising conductors 28 and 29. The source of unidirectional voltage may be produced by a suitable means, such as a full wave rectifier 30, including a transformer 3! and a pair of unidirectional conducting devices 32. A voltage divider comprising a resistance 33, which is connected across conductors 28 and 29, is arranged to have adjustable contacts 34 and 35. Capacitance 36 is connected to be energized from the direct current circuit, including conductors 28 and 29, through an adjustable resistance 31. A periodic timing quantity, such as a periodic voltage, is generated by periodically discharging the capacitance 36 through an electric valve 38. Electric valve 38 is preferably of the type employing an ionizable medium and comprises a control member 39. In order to render the electric valve 38 nonconductive after each discharge of capacitance 36, I connect an inductance 40 in series relation therewith. As an agency for effecting the proper and desired synchronization between the voltage of the alternating current circuit 2 and the time at which the periodic voltage impulses occur, I employ a transformer 4! having a primary winding 42 and a secondary winding 43. Primary winding 42 is connected to the alternating current circuit 2 through any suitable phase shifting device such as a rotary phase shifter 44. By adjustment of the rotary phase shifter 44, it is possible to control the phase relation between the voltage of the alternating current circuit 2 and the time of initiation of the various impulses of the periodic voltage. Secondary winding 43 is connected between the adjustable contact 34 of the voltage divider and the control member 39 of electric valve 38. Where it is desired to obtain a periodic timing quantity, such as periodic voltage which is of pronounced peaked wave form, such as in those applications where it is desired to maintain a high ratio of the period of nonconduction to the period of conduction of the electric valves, I employ a serially connected resistance 45 and a capacitance 46 which is connected to be energized in accordance with the voltage appearing across the terminals of resistance 31. This circuit is disclosed and claimed in United States Letters Patent No. 2,098,052,

granted November 2, 1937, on an application of Harold W. Lord, and which is assigned to the assignee of the present application.

To efiect energization of the control members ll of electric valves l and 8 in groups 4 and in a predetermined order, I provide a switching device 41. The switching device 41 comprises an armature member 48, a core member 49, an associated actuating coil 50, and two groups of contactor mechanisms 5| and 52. The contactor mechanisms 5| and 52 are similar in construction and arrangement and are associated with groups of valves 4 and 5, respectively. The contactor mechanism 5| includes stationary contacts 52 which are associated with electric valve 1 in group 4 and stationary contacts 54 which are associated with electric valve 8 in group 4. Movable contacts 55 and 55 are mounted on the armature member 43 and are arranged to be in .overlapping relation with the contacts 53 and 54, that is, are arranged to have periods of simultaneous closure therewith during the reciprocating action of member 48. This overlapping action may be obtained by any suitable arrange ment and is diagrammatically illustrated as being accomplished by the utilization of a spring 5! which tends to maintain the movable contacts 55 and 56 in spaced relation. A collar 58, which is mounted on the member 48, moves the contact 56 out of engagement with the stationary contacts 54 when the movable member 48 is in the upper position, that is, when the actuating coil 50 is energized. When the member 48 is in the lower position, that is, in the deenergized position, the contactor mechanism attains the position shown in the drawing. contactor mechanism 52 includes stationary contacts 59 and 55 which are associated with electric valves 7 and 8, respectively, in group 5, and movable contacts 51 and 62 are associated with stationary contacts 59 and 50. respectively.

To obtain periodic energization of the actuating coil 59 of the switching device 41 so that the member 48 reciprocates to effect alternate energization of the control members H of electric valves 1 and 8 in groups 4 and 5, I provide a circuit 63 which may comprise a pair of relays 64 and 65. Relay 64 periodically energizes actuating coil 58 of the switching device 41 from a source of current 66. Where the source of current is alternating and where it is desired to energize the coil 5!! with direct current, a suitable rectifying arrangement, such as a full wave rectifier 61, may be interposed between the source and the coil 55. Relay 55, which is ener ized in response to the operation of relay 64. effects deenergization of the relay 54 when relay 64 is in the energized position so that a pumping action is obtained between relays t4 and 55. Relay 64 comprises an armature 58, an actuating coil 69, pairs of stationary contacts is and H, and a movable contact member 12. When the relay 54 is in the deenergized position, that is, in the lower position, coil 5!! of the switching device 41 is energized, and when the member 68 of relay 5A is in the energized or upper position, the coil 5!! is deenergized and relay 55 is energized. A suitable rectifying device l3 may be interposed between the source 65 and the actuating coil 69 of relay 54, if desired. Relay 55 includes movable contact l4 and stationary contacts 15 and an actuating coil 75 which is energized by the relay 64 from the source 55 when the relay 54 is in the energized position. A rectifier Tl may also be used in connection with relay 55, if desired, and

current limiting resistances 18 and 19 may be connected in the relay circuits to obtain the desired value of control currents. It is to be noted that relays 64 and 65 are interlocked to provide intermittent or periodic energization of the actuating coil 50 of the switching device 41.

The operation of the embodiment of my invention shown in the single figure of the drawing will be explained by considering the system when it is operating to efiect periodic energization of the load circuit I. As is well understood by those skilled in the art, the electric valves in the groups and 5 conduct current to transmit alternating current to the load circuit l in the event the periodic voltage produced by the timing circuit 2? is of sufficient period. The excitation circuits #2 and l3, which are energized. in accordance with the anode-cathode voltages of the respective groups of valves, transmit current to the immersion-ignitor control members H when the timing circuit 2'? dictates such energization. During the intervals when the timing circuit 21 dictates energization of the control members H, the control electric valve i l of excitation circuit l2 is rendered conductive by the positive voltage appearing across the terminals of the resistance 25 in excitation circuit l2, and electric valve Hi conducts current to the immersion-ignitor control member l 5 until are discharges are initiated in the associated valves. As soon as arc discharges are initiated, the current through the immersion-ignitor control members decreases to substantially a zero value by virtue of the lower resistance of the main discharge paths of the electric valves. This action will be understood when it considered that the anode-cathode voltage decays substantially as soon as electric valve i or 8 is rendered conductive.

Electric valves 1 and 5 of group 5 follow the electric valves '5 and 8 of group 4. That is, the former electric valves are rendered conductive only after the electric valves in group 4 effect energization of the load circuit 5. The voltage appearing across the terminals of the primary winding of transformer 3 energize transformer 53" to introduce into excitation circuit it a voltage sufficient in magnitude to overcome the effect of the negative bias ng potential, so that the control electric valve E4 in excitation circuit 53 effects energization of the immersion-ignitor control member H of either valve 1 or 8 in group depending upon the position of the movable element Q8 of the switching device 5?.

The manner in which the timing circuit 27 generates the periodic voltage is well understood by those skilled in the art. Briefly described, the periodic voltage is generated by the periodic charging and discharging of the capacitance 35. For a more detailed explanation of the operation of this circuit, reference may be had to the above second mentioned patent of Harold W. Lord.

Switching device l"! alternately energizes con" trol members ll of electric valves l and E! in groups i and 5, so that electric valves '3 and 8 conduct current alternately to increase the continuous rating of the valve grcup by uti 'zing the substantially greater short-time or momentary ratings of these valves. Actuating coil 55 is periodically energized by means of the relays 5 and 55 so that the member Q8 of device All attains a reciprocating action. Due to the fact that the movable contacts 55 and arranged to have an overlapping action with respect to the associated stationary contacts 53 and 54, respectively, the excitation circuits l2 and i3 will always be connected to at least one of the control chambers H.

The position of the movable m mbers of the switching device 4'! and relays B t and 65 shown in the drawing is that which is attained when the system is deenergized. As soon as switch 6 is moved to the closed circuit position, coil 69 of relay 6 is energized, raising movable contact 72 to disengage stationary contacts 16 and to engage stationary contacts 1' I. By such action, coil is maintained deenergized and coil 16 of relay 65 is energized. As soon as coil E5 of relay 65 is energized, movable contact 14 thereof disengages contacts 15, effecting decnergization of actuating coil 69 or relay 64. Upon such deenergization, movable contact 72 will engage station.- ary contacts 10, efiecting energization of the actuating coil of the switching device ll and moving the member 38 to the upper position. A pumping or interlocking action is maintained between relays 64 and '55 so that the actuating coil 50 is periodically energized. In this manner the control members H of electric valves 1 and 8 in groups 4 and 5 are alternately energized to cause the electric valves '5 and B to conduct current alternately. Furthermore, due to the periods of simultaneous closure of the contactor mechanisms of this device, at least one of the control members of the valves in each group is always connected to the associated excitation circuit.

While I have shown and described my invention as applied to a particular system of connections and as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications may be made wtihout 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 combination, a supply circuit, a load circuit, an electric translating circuit interconnecting said circuits and including electric valve means having a plurality of discharge paths connected in parallel relation across the same points of potential difierence in said translating circuit and being connected to conduct current in the same direction, said electric valve means each being provided with a control member for initiating discharges in the associated discharge path, means for generating a voltage to energize the control members, and means for energizing the control members in a predetermined order to cause said discharge paths to conduct current in said order and including switching means having overlapping contacts to assure that one of the control members is always connected to said first mentioned means.

2. In combination, a supply circuit, a load circuit, an electric translating circuit interconnecting said circuits and including electric valve means having a plurality of discharge paths connected in parallel relation across the same points of potential difierence in said translating circuit and being connected to conduct current in the same direction, said electric valve means each being provided with a control member for initiating discharges in the associated discharge path, a source-of current, switching means having overlapping contacts to assure that one of said control members is always connected to said source, said switching means including an actuating coil, and means for periodically energizing and deenergizing said coil to energize the control members in a predetermined order so that the discharge paths conduct current in said order com prising a relay for periodically energizing said coil and a second relay responsive to the operation of the first mentioned relay for efiecting periodic operation of said first mentioned relay.

3. In combination, a supply circuit, a load circuit, an electric translating circuit interconnecting said circuits and including electric valve means having a plurality of discharge paths connected in parallel relation across the same points of potential difference in said translating circuit and being connected to conduct current in the same direction, said electric valve means each being provided with a control member for initiating discharges in the associated discharge path, a source of current, a switching device for connecting said source to the control members and including sets of contacts having periods of simultaneous closure to assure that one of the control members is always connected to said source, said switching device including an actuating coil, and means for periodically energizing and deenergizing said coil to energize the control members in a predetermined order so that the discharge paths conduct current in the same order and comprising a pair of interlocked relays for efiecting periodic energization of said coil.

4. In combination, a supply circuit, a load circuit, an electric translating circuit interconnecting said circuits and including electric valve means having a pair of discharge paths connected in parallel relation across the same points of potential difference in said translating circuit and being connected to conduct current in the same direction, said electric discharge means each being provided with a control member for initiating discharges in the associated discharge paths, a source of current, a switching device for connecting said source to the control members and including two sets of overlapping contacts having periods of simultaneous closure to assure that one of the control members is always connected to said source, said switching device including an actuating coil, and means for periodically energizing said coil to eifect alternate energization of the control members including a relay for periodically energizing and deenergizing said coil and a second relay controlled by the first mentioned relay for effecting periodic operation thereof.

5. In combination, an alternating current circuit, a load circuit, an electric translating circuit interconnecting said circuits and including electric valve means having a pair of discharge paths connected in parallel relation across the same points of potential diilerence in said translating circuit and being connected to conduct current in the same direction, each of said discharge paths being provided with an anode, a cathode and an immersion-ignitor control member, an excitation circuit connected to be energized in accordance with the anode-cathode voltage of said discharge paths, a switching device including two sets of overlapping contacts having periods of simultaneous closure to assure that one of the control members is always connected to said excitation circuit, said switching device including an actu ating coil, and means for periodically energizing said coil to eiTect alternate energization of the control members so that said discharge paths conduct current alternately.

6. In combination, an alternating current supply circuit, a load circuit, an electric translating circuit interconnecting said circuits and including 76 device including two sets of overlapping contacts having periods of simultaneous closure to assure thatlone of the control members is always connected to said controlled electric valve, said switching device including an actuating coil, and means for periodically energizing said coil to effect alternate energization of the control members so that said discharge paths conduct current alternately.

DUDLEY E. CHAMBERS.

CERTIFICATE OF CORRECTION.

Patent No. 2,167,h98. July 25, 19 9.

' DUDLEY E. CHAMBERS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 5, and second column, line 11, for "ironizable" read ionizable; second column, line 51, for "singe" read single; page 2, first column, line L O, for "ionizing" read ionizable; page 5, first column, line 15, for the reference numeral "52" read 55; page h, first column, line 5, for the word "chambers" read members; linel, for "or" read of; line 57, for "wtihout" read without; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and. sealed this 5th da; of September, Aa D, 1959,

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

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