US2215906A - Electric valve control system - Google Patents

Description

- Sept. 24, 1940. E. M. KAEGI- ELECTRIC VALVE CONTROL SYSTEM Filed April 21, 1951 s Shets-Sheei 1v Sept; 24, 1940. E M KAEG, 2,215,906

ELECTRIC VALVE CONTROL SYSTEM Filed Aril 21, 195': s sheets-sneet 2 Patented Sept. 24. 1940 UNITED STATES PATENT OFFICE 7 2,215,906 nnnc'rmc VALVE CONTROL SYSTEM poration of Delaware Application April 21, 1937, seen No. 13%,159

. 2 Claims. This invention relates in general to improvements in electric valve control systems, and more particularly to means for controlling the operation of an electric valve controlling the flow of current in a circuit operating at such high voltage as to render the insulation of control apparatus associated with the valve difficult and ex-' pensive.

Electric valves are frequently utilized for controlling the flow of current in circuits at high other waves.

' voltages, one example of such use being the rectification of current at a voltage ofseveral thousand volts for supplying radio broadcasting transmitters. It has also been proposed to utilize electric valves for rectifying current to betransmitted at high voltage between a generating station and a substation distant therefrom, and

also for converting the direct current to alter-- nating current at such distant substation. Such valves generally require, for the control thereof, a large number of supervisory and protective devices which are connected with themain high voltage circuit controlled by the valve and with an auxiliary circuit of such low voltage as to be without danger for the operators who may come into accidental contact therewith. Such devices must therefore be insulated for the full voltage of the main circuit to ground, or else the circuits of such devices must include insulating transformers likewise insulated for the full main circuit voltage to ground. Such insulation is frequently difficult to provide and always adds considerably to the cost of the installation.

It is therefore more advantageous to separate each control device into two portions having no physical contact with each other and to transmit control impulses from one portion to the other of the device by means of. electromagnetic or Although waves of any frequency may be utilized, such as the so-called infra-red, ultra-violet, radio waves, or sound waves,v it is generally more convenient to utilize light waves produced in one portion of the control device and ?focused on a light sensitive device forming part of the other portion. More particularly, it is preferable to utilize electric light sources which are caused to receive current only when a control impulse is to be transmitted so as to lengthen the life of the light sources utilized.

It is therefore one of the objects of themesent invention to provide an electric valve control system in which control impulses are transmitted between an intermittently operating source of electromagnetic or'other waves anda device sensitive to such waves.

Another object of the present invention is to provide an electric valve control system in which control impulses are transmitted between an in termittently operating source of light and a light sensitive device.

Another object of the present invention provide an electric valve control systemin which a plurality of different control operations utilize control impulses transmitted'between a common source of light and a common light sensitive device.

Objects and advantages other than those above set forth will be apparent from the following description when read in connectionwith the accompanying drawings, in which:

Fig. 1- and Fig. 1a together diagrammatically illustrate an electric valve converting system in which different control operations are effected by 'means ,of control impulses transmitted between light sources and light". sensitive devices;

Fig. 2 diagrammatically illustrates the rela- .tionship*-between the coils and the contacts of some of the relays utilized in the system illustrated in Figs. 1 and 141;

Fig. 3 diagrammatically illustrates the arrangement and the connections of any one of the electronic relays utilized in the system illustrated in Figs. 1 and 1a; and

Fig. 4 illustrates one example of a physical arrangement of the system illustrated in Figs. 1 and 1a.

Referring more particularly to the drawings by characters of reference, reference numeral 6 designates an alternating current line or circuit connected with a suitable generator (not shown) and serving as a. source of electric current for a main electric circuit 1. Circuits 6 and I are connectedby means of a switch 8, a transformer 9 having a primary winding II and a secondary winding l2, and one or more electric valves i3. Circuit 6 also supplies current to an auxiliary transformer it having the secondary winding thereof connected with a. grounded auxiliary circuit it for the control of valves I 3. Circuit I6 is thus insulated from circuit 1 by means of transformers 9 and i4 and operates at such low voltage as to be without danger for the operators in charge of the system. Circuit 6 is also con-- Valves I 3 are provided for rectifying current isto supplied thereto from winding 12 and to thereby control the flow of current through circuit I. 'Such valves may be of any type known in the art and are herein assumed to be of the discontinuously controllable or vapor type each having "and with the neutral conductor of circuit IS.

The operation of valves I3 is controlled by a plurality of control means each connected with one of circuits 1 and I5 and each comprising a device sensitive to electromagnetic or other waves such as a light sensitive device. A suitable source of electromagnetic or other waves such as an electric light source is arranged to illuminate the light sensitive device and is associated with suitable means connected with the other one of circuits 1 and ii for controlling the supply of current to the light source for the purpose of operating the associated control means. ticularly, means connected with circuit 1 are provided for controlling the conductivity of valves 13 by establishing and maintaining an electron emission at cathode 22. Such means comprise an ignition anode 23 suspended from a spring 24 and provided with an armature 25. 'A solenoid 21 cooperates with armature 26 to cause operation of the ignition anode. The ignition anode is connected with the secondary winding of a transformer 28 through spring 24, a resistor 23, contact 3la of a relay 3| and contact 3211. of a relay 32. Solenoid 21 is connected between the secondary winding terminals of transformer 28 through contact 33aof a relay 33 and through contact 32b of relay 32. The secondary winding neutral point of transformer 28 is connected with cathode 22 through the coils of relays 3| and 33 and through a reactor 34 connected in parallel with a second reactor 36 through contact 3lb of relay 3!. The

secondary winding terminals of transformer 28 are also connected with a pair of excitation anodes 30 of valves I! through a pair of resistors 35.

The coil of relay 32 is connected with circuit I 9 through an electronic relay generally designated by 31 and controlled by a light sensitive device 38. Device 38 may be of any suitable known type such as the soecalled selenium cells and photo voltaic cells, but is preferably of the type known sea-phototube. Such phototube comprises essentially a glass bulb'containing two electrodes separated by a space having a conductivity depending on the degree of illumination of the bulb. Relay 31 may be of any known type adapt-- ed to be controlled by phototube 38. One example of such type of relay is diagrammatically illustrated in Fig. 3, which may be assumed to be representative of all the electronic relays utilized in the system illustrated in Fig. 1. Such relay comprises a transformer 39 which,'in the present instance, is energized from circuit H, but which may be energized from circuit l6 when the device to be controlled thereby is connected with the low More parerably connected in parallel with the coil of relay 32 to render the flow of current therethrough more uniform.

A suitable source of light such as an electric lamp 44 is arranged to illuminate phototube 33. Lamp 44 is preferably of the incandescent type and is provided with suitable means connected with circuit it such as a push button switch 46 for controlling the supply of current from circuit i6 to the filament of the lamp to cause operation of relay 32. The light produced by lamp 44 may be focused on phototube 38 by means of a lens 41 or of an equivalent optical system, and phototube 38 may be shielded against light emitted by sources other than lamp 44 by means of ahood 43. The primary winding of transformer 23 may be connected across two conductors of circuit 13- controlled by additional means which are also connected with circuit 1 and controlled by means of light sources energized from circuit i5.. Such means .comprise a plurality of control electrodes 56 severally associated with anodes 2| and serving to control the moments of initiation of the periods of current flow through each anode. Such moments are determined by the impression on each control electrode of potential varying from a negative value to a positive value relative to the potential of cathode 22 taken as datum for control potentials. Each control electrode is accordingly connected through a current limiting resistor 51 with one of the phase. portions of the secondary winding 58 of a control transformer 59 having a primary .winding 6|. Winding 5| is connected with circuit l9 through a plurality of current limiting resistors 52 andthrough the coils of three relays 63, 64 and 55. Relays 53, 54 are provided for additionally controlling the conductivity of valves l3 and operate responsive to an abnormal operating condition of the valves for rendering the valves non-conductive. Relay 66 is of the lookout type operable to close a contact controlling the supply of current to a light source only after a predetermined number of operations of relays 63 and 5. Relay 63 is a. fast acting relay provided with contacts 53a, 63b arranged to short circuit the difierent portions of winding 8|. One of resistors 82 is connected in parallel with a circuit comprising the serial arrangement of an indicating device 61, contact 54a of relay 64, and the coil of another relay 69. The coil 01' relay 63 is connected with the secondary winding of a current transformer -1l having the primary winding thereof energized from a current transformer 12 connected between circuit 6 and switch 8. The secondary circuit of current transformer 12 is preferably grounded, and current transformer 1| serves to insulate such circuit from circuits l9 and 1.

Current transformer 12 and two other current transformers 13 and 14 in the connections between circuit 6 and switch 8 supply current to the coils of three relatively slowly acting overload relays 18, 11, 18. The coil of relay 16 is bridged by a-resistor 19 and contact 3: of a relay 8!. The coil of relay 11 is bridged by another resistor 82 and contact lib of relay I. The coil of relay i8 is connected in series with the. coil of relay 8i connected in parallel with a resistor 83. through-contact Bio of relay 8|. Relays ll,

- 'I'I, It are provided with contacts 18a, .I'Ia, 13a

connected in parallel and operable to short circuit the holding coil to of switch 8 through an indicating device 84 and through contacts 8b of switch 8. When switch 8 is closed, holding coil 8a is normally supplied with current from circuit it through a resistor 86. a push button switch I and contacts 8b to maintain latch to of switch 8 in the operative position thereof.

The secondary winding 68 of transformer 59 is connected in star .to form a neutral point connected with cathode 22 through a capacitor 98 and through the taps of two rheostats 89 and SI. Rheostat 89 is associated with two resistors 92 and as to form a voltage divider receiving.

current from a direct current generator e4.- Rheostat 9i is associated with two other resistors 9t and or to form a second voltage divider also receivingcurrent from generator 96. Generator 9% is driven by a motor 88 connected with circuit is through a switch 99.. Switch 89 is controlled by an electronic relay it! connected with a phototube M2. The operation or relayifli is controlled by a lamp I08 receiving current from circuit I6 through a switch IM. The taps of rheostats t9 and ti are movable for impressing a variable potential fromgenerator at on control electrodes 56 to control the operation of valves i8. For controlling the operation of such. potential impressing means; the

taps are Jointly actuated by a reversible electric motor I08 of any suitableknown type. Motor I06 is assumed to have a squirrel cage armature and an exciting winding energized from circuit I9, and to be provided with a pair of shading coils severally-adapted to be short circuited by means of relays WI and I08. Such action of .the relays may be controlled by suitable limit switches such as at no. Relay I61 is controlled by a relay Ilia connected with a phototube III cooperating with a lamp H2 connected with circuit it through a switch Iii. Relay IN is controlled by a may ill connected with a phototube H6 cooperating with a lamp iii connected with circuit it through a switch H8. The neutral point of. winding so may also be connected with cathode 22 through generator 96 upon operation of contacts 53c, 53d, 63e, 83f of relay 63 or of contacts sac, 89d, 69c and 89] oi relay 89. Valves I3 are generally provided with means 'for controlling the vapor pressure within the phototube its cooperatingwith a lamp I28 con nected with circuit I6 through a. switch I21. Pump H9 is preferably provided with a water jacket having suitable cooling, means such as a radiator I28. Pump 9 discharges into another pump I28 of the sliding vane type driven by a motor i3l.

circuit is through a switch I32 controlled by a relay I 33 connected with a phototube I34. The phototube cooperates with a lamp lfl'connected with circuit I 8 through a switch IS'I.

The control. system comprises a plurality of means connected with circuits I and I9 and each Motor I3I is connected with or otherwise controlling the supply of current to a light source to cause operation of suitable controlling means for the valves. such as switch 8 or of other means for causing interruption of the flow 0! current through the valves. The responsive means include relay 86 operable in dependence upon the flow of current through the switch 8 and interrfiption of the flow of current through valves 23. Relay I 22 responsive to the flow of current through heater no is provided with a contact i22a for connecting lamp I38 with circuit it through an indicating device IM'.

Valves I 3 are also provided with means connected with circuit I- and responsive to an operating condition other than an electrical condition of valves 83 for controlling the supply of current to lamp I38. Such means comprise means responsive to a physical condition of the operating vapor within valves itsuch as the temperature or the pressure thereof. The temperature responsive means comprise atemperature responsive device I 46 having a' contact idfia operable to connect lamp I38 with circuit Itthrough an indicating device I. The pressure responsive means comprise a resistor Idii in contact with the operating vapor within the valve and forming part ofa resistance bridge its. The

bridge receives rectified current from circuit I 9 through a rectifier ISI, and the flow of such current through the bridge is afiected by the changes in the resistance value of resistor M8 in response to the variation 0! temperature thereof resulting from variations of the vapor pressure thereabout. The output terminals of brid e I49 areconneoted to an indicating device H2 and to a relay I53 having a contact IbSa operable to connect lamp 8 with circuit i9 through an indicating device IM. A second temperature responsive device idt mounted on the water circulating system of pump ii 9 is providedwith a contact Ibfia adapted to connect lamp itt with circuit i9 through an indicating device I81.

To prevent continuous operation of valves is when one or more of the conductors of circuit l9 accidentally become deenergized, three lamps I 58 are permanently connected between the different conductors oi circuit I9 and are arranged to illuminate a single phototube I59. Phototube I 59 is connected with a relay ISI controlling a relay I62 having a contact IBM for short 'circuitin holding coil 8a through an indicating device iti. Phototube IE9 is selected of such char- "acteristic as to cause operation oi relay I62 if one or more 01' lamps I58 cease to operate.

Fig. 4 illustrates one manner of arranging the equipment diagrammaticallyillustrated in Figs. 1. 1a, 2 and 3. Valves iifthe associatedmechanical equipment and the different devices connected with circuit i9 are mounted on a platmm supported on insulators I68. The apparatus connected with circuit I6 and with current transformers 12,13. I! are mounted on a switchboard I81 separated from the high voltage equipment by a fence" I68.

The operation ofthe system will be considered assuming that circuit 8 is energized from the generator connected therewith and that the diflerent receives an amount of light from the lamps sufflcient to cause operation of relay I52. Such operation will be considered somewhat in detail assuming that relay- IGI is of the type represented in Fig. '3. As long as lamps I58 remain dark phototube I59 is substantially non-conductive. The associated transformer 39 then charges capacitor 42 through the cathode of the associated valve 4| and through the grid of the valve acting as an anode. The charge taken by the capacitor is such that the grid of the valve is at a variable negative potential with respect to the potential of the cathode of valve 4I at least when the associated anode is at a positive potential with respect to the cathode potential. Valve H is then substantially non-conductive for the flow of current between the anode and the cathode thereof.v

When lamps I53 receive current and illuminate phototube I59, the phototube becomes materially conductive and connects the grid of valve 4| with the anode thereof. Capacitor 42 discharges and the grid-oi; valve 4I may reach a positive potential with respect to the potential of the vcathode when the associated anode is likewise at a positive potential. The valve .is then conductive, and a pulsating current' is transmitted from trans-- former 39 through the coil of relay I82 and through valve 4I.

means of capacitor 43. The above described method of operation is characteristic of all the electronic relays utilized in the system and will therefore not be repeated in connection with the description of the operation of each individual relay.

Relay I62 operates upon energization of the coil thereof to open contact I82a in circuit with the holding coil 80. of switch 8 to permit subsequent closure of the switch. Switch I2'I is then closed to supply current to lamp I28 and the lamp illuminates phototube I24. As a result thereof relay I23 causes relay I2I to complete the circuit of heater I20. Switch I31 may also be closed to supply current to lamp I36. The lamp illuminates phototube I34 to cause relay I32 to connect motor I3I with circuit I8. Motor I3i thereupon starts pump I29 and maintains such pump in continuous operation. Switches I 21 and I3I'must, however, remain closed unless relays I 2| and I32 are provided with holding coils.

When the vapor pressure within'valves I3 has been lowered to the required extent by operation of the pumps, switch 54 may be closed .to supply .current to lamp 53 which thereupon illuminates. phototube 82. Such operation causes relay 49 to .operate to connect transformer 28 across twoconductors of circuit I9.- If relay 49 is provided with a holding coil, switch 84 may then be opened and relay 49 will remain inthe energized position untilswitch I1 is opened. Push button 43 may then be actuated to supply current to lamp 44 through contact 4811. At the same time contact no short circuits holdingcoil 8a of switch I,

;to cause opening of the switch if it has been'inadvertently closed. Lamp 44 illuminates photo- The flow or current through' the coil is rendered substantially uniform by- 2,21s,aoa

cell 38 with the result that relay 32 closes the contacts thereof. Contacts 32b and 33a connect solenoid 21 across the secondary winding of transformer 28 and the solenoid accordingly urges armature 23 downward to cause ignition anode 23 to come in contact with cathode 22. Contact 32a completes a circuit from the secondary winding of transformer 28 through contacts 32a, 3Ia, resistor 29, spring 24, ignition anode 23, cathode 22, the coils of relays 3| and 33, reactor 3'4 and reactor 38 and contact 3Ib back to the transformer. Relay 33 operates in response to the flow of current cathode 22 and flows to the neutral point of the secondary winding of -transformer 28 by way of the coils of relays 3i and 33 and of reactors 34 and 38. Relay 3| thereupon operates to open contacts 3Ia and 3Ib to thereby disconnect ignition.an0de 23 and reactor 38 from the circuit.

Push button switch 48 may then be released,

thereby causing relay 32 to return to the position shown. Contact 43b is also qpened to permit subsequent closure of switch 3. 1

Switch I04'is thereafter (closed to supply current to'lamp I03. Pho'totube I02 i'silluminated by the lamp and causes switch 99 to connect motor '38 with circuit I9. 'Motor 98 accordingly starts and drives generator 4 which supplies direct current to voltage dividers 92, 89, 93 and 96 9|, 91. Switch H8 is then cl momentarily -to supply current to lamp II I 0 cause operation of relay I08. Such relay'short circuits the shading coil on the fight hand side of motor I86. Motor I08 accordingly rotates until opening of limit switch IIO to actuate the tap of rheostats 89 and 9| in such manner as to impress a maximum negative potential on the neutral point of winding 58.

Each control electrode 58 of valves I3 is then subjected to an alternating potential from winding 88 superposed on a maximum negative potential received from generator 94 through the voltage dividers;

8c thereof which is urged in latching position by coil 80 energized from circuit I8 through resistor 88, push button switch 81 and contact 8b. I

"Upon closure of the switch the diiiferent anodes 2I are brought sequentially to'a positive potential with respect to the potential of cathode 22. By reason of the adjustment of rheostats 89 and 9|, the control electrode 83 associated with each anode 2| becomes positive with respect to the potential of cathode 22 to'release the flow of current through the associated anode at moments of the voltage cycle of circuit 6 when the associated anode has a potential of relatively low value. The output voltage of the systemimpressed on circuit -'I-is then of relatively low value as is well known. Switch II3 may then be closed for a suitable period of time to supply current to lamp II2. Relay IN is thus caused'to oper- -ate and to short circuit the shading coil on the left hand side of motor I08. Motor I08 is thus caused to rotate in a direction opposite to the direction of rotation previously considered.- The adjustment of-rheostats 89 and 9i is thus gradu- Switch 3 may then be closed and the switch is maintained closed by means of latch ally varied to decrease the unidirectional potential component impressed on the control electrodes it through the voltage dividers. Each control electrode then becomes positive with respect to cathode 22 at an earlier moment of the voltage cycle of circuit 6. The output voltage of valves I8 is accordingly gradually increased as is well known and 'switch II3 may be opened to cause motor we to stop when the voltage of circuit I has reached the desired value. Such voltage may also be adjusted from time to time by varying the adjustment of rheostats 89 and 9! to regulate the flow of current through valves I3. Such adjustment may also be effected automatically in response to an operating condition of valves I 3 such as the voltage oi circuit I or the magnitude of the how of current therethrough as is well known.

During such operation current transiorm'ers I 12, I3, 14 supply currents to relays i8, i1, I8.

and 63 which are of insufiicient value to cause operation of the relays. Upon occurrence of an abnormal condition in the operation of the system causing a flow of current of excessive value through valves I3, current transformer i2 acting through current transformer 'II supplies the coil of relay 83 with current of sufllcient magnitude to cause the relay to operate. Relay 83 short circuits winding Si by means of contactstiia, 63b. Relay 63 also connects the neutral point of winding 58 with cathode 22 through generator 94 by means of contacts 63d, 63f and disconnects the voltage dividers by means of contacts 630, 63c. The control electrodes of valves I3 are thus maintained continuously at a negative potential with respect to the potential of cathode 22 and the flow or current through valves I3 is thereby caused to cease as is well known.

Closure of contacts 83a, 63b causes circuit I9 to supply current to the coils of relays 63, 64

and 66 of sumcient magnitude to maintain relay 63 energized after interruption of the flow of [current through valves I3 and to cause relay 6 to operate to close contact Ma after a time delay. The coiloi relay 69 is energized through contact 64a and relay 68 actuates contacts 69:: to 69 thereof to relieve the contacts of relay 63 from further duty. Contact 690. also short circuits the p therein without departing from the spirit of the coil of relay 8%, which returns to the position shown, and contact 692; short circuits the coil oi relay 6d, which opens contact 64a. Relay 59 then also returns to the position shown and the flow oi current through valves i3 is reestablished. Such operation of the relays is indicated by means indicator 61 and is also registered temporarily by relay 66. If the abnormal operating condition of the system is such that the current therethrough again reaches an excessive value upon being reestablished, the above sequence of operation is repeated for rendering valves I3 non-.- conductive. Upon repetition 01' such sequence of operation a predetermined number of times within a predetermined time period, relay 66 closes contact 66a, thereby causing lamp I38 to receive current from circuit I9. Lamp I38 illuminates phototu-be I38 and causes operation of relay I42. Relay I42 closes contact I42a, thus short circuiting holding coil to of switch 8 through contact 8b and through indicating device I43. latch 80 oi. switch 8 is thereby released and the switch opens.

If after one cycle of operation of'relays 63, 84, 66 and 69 the flow or current through valves I3 is not completely interrupted for any reason such as faulty operation of control electrodes 56,

relay 83 remains energized from current trans- -iormer I2 through current transformer 'II and ate, the coils of relays I6, ll, .18 receive sufficient current from-current transformers I2, 13, I4 for a sufficient length of time to cause operation of the relays andresulting opening of switch 8.

Switch 8 is also caused to open in dependence upon the how of current through different portions of auxiliary circuit I8 by means other than relay 66 comprising relay I22 and lamps I58. If at least one of lamps I 58 ceases to operate, phototube I59 loses suflicient conductivity to *cause relay I82 to operate to close contact B6211,

to thereby cause switch 8 to be opened.

If'the flow of current through heater I 20 fails, relay I22 closes contact I22a which connects lamp I38 with circuit is through indicator I44.

If the temperature or the operating vapor within valve I3 becomes excessively high, device MB closes contact I46a connecting lamp I38 with circuit is through indicator it]. If the temperature oi. the water jacket of pump us becomes excessively high, device ISG closes contact i561; connecting lamp I38 with circuit I9. through indicating device I51. Ii. the pressure of the vapor within valves I3. becomes excessively high, the balance of bridge I49 is aiTected in such manner that relay I53 operates to close contact i53a connecting lamp I38 with circuit I9 through indicator' I54. When lamp I38 is connected with circuit I9 through either of the contacts associated therewith, the lamp illuminates phototube I39 and switch 8 is caused to open to disconnect it will be apparent to those skilled in the art that various changes and modifications may be made invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an electric valve control system, the combination with a main electric current circuit, an

electric valve connected to said main circuit forcontrolling the flowoi. current therethrough, a source oi electric current for said main circuit, a switch for connecting said source to said main circuit, an auxiliary electric current circuit insulated from said main circuit, and a second auxiliary electric current circuit connected to said main circuit comprising means for controlling the conductivity of said valve responsive to .an abnormal operating condition 0! said valve for rendering said valve non-conductive, of means connected to the first said auxiliary circuit and comprising a light sensitive device for controlling the operation of said switch, an electric light source arranged to illuminate said light sensitive device, and means responsive to the occurrence o! a plurality of operations oi said conductivity controlling means within a predetermined period:

oi time for controlling the supply of current to said light source to cause opening of said switch.

2. In an electric valve control system, the combination with an electric current circuit, an electric valve, means comprising a switch for eflecting the connection of said circuit with said valve for the flow of current therethrough, of means for controlling said flow of current comprising an element of said valve, means for impressing a potential on said element to control the conductivity of said valve, means comprising a light sensitive device for varying the magnitude of said potential in such a sense as to regulate the said flow of current, means for causing operation of said light sensitive device, a second light. sensitive device, means operable responsive to an abnormal operating condition of said valve tor varying said potential in such a sense as to render said valve non-conductive and for causing operation of the second said light sensitive ANNA E. KAEGI,

Special Administratria: of the Estate of Emil M. K660i, Deceased.

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