US2529127A - Fire extinguishing system - Google Patents

Description

Nov. 7, 1950 w. A. BEACH 2,529,127

- FIRE EXTINGUISHING svs'rm Filed Oct. 25, 1945 2 Sheets-Sheet 1 IN V EN TOR.

.iIiZlierABeaa/E TOE/YE) Nov. 7, 1950 w. A. BEACH FIRE EXTINGUISHING SYSTEM 2 Sheets-Sheet 2 Filed Oct. 25, 1945 confirm/yr 6/ 660 Mo foe INVENTOR. lVa/lerjfleaafi Patented Nov. 7, 1950 Walter A. Beach, Chicago, 111., assignor a 'Cardox Corporation, Chicago, 111., a corporation of Illinois Application October 25, 1945, Serial No. 624,410 11 Claims. (01. 1c9 9 This invention relates to fire-extinguishing systems employing carbon dioxide .as the extinguishing medium and more particularly to the control .system for regulating the delivery of this medium.

In general, the present the extinguishing system is based on the method disclosed and claimed in the patent to Eric Geertz, Number 2,143,311, issued January 10, 1-939. That system employs a storage tank of large capacity in which liquid carbon dioxide is maintained .at a low temperature and a correspondingly low pressure. The liquid .carbon dioxide stored in this manner may selectively protect a plurality of independent hazards each of which is supplied with liquid carbon dioxide through a branch pipe from a header connected to the storage tank.

The branch pipes which extend from the header to the individual hazards to be protected are controlled by' separate selector valves. It is possible to operate a system in which the header and the branch pipes are under the pressure of the supply tank so that delivery upon any desired hazard may-be accomplished by merely opening the proper selector valve. However, it is preferable that the header and branch pipes be under no pressure as this reduces the requirement that the pipe connections and selector valves be, gas-tight. It is, therefore, preferable to employ a master valve in the header close to the supply tank and which is normally closed. When a selector valve in one of the branch pipes is then opened to dis- 2 charge liquid'carbon dioxide, it is consequently necessary that the master valve in the header be opened,

It is impractical for an attendant to manuallyopen the proper selector valve and then go to the master valve in the header, because of the time which would be lost, particularly if these valves were spaced at considerable distances. The systems which have been devised,thereiore, include a control means generally involving an electrical circuit which will automatically open the master valve when a selector valve is'opened. However, such a system involves the disadvantage that the master valve may remain open for an unnecessary length of time, because the attendant forgets to shut it off.

If the master valve is allowed to remain open for too long a period, the liquid carbon dioxide may become fully spent. view of the expense of liquid carbon dioxide it is important that some, means he provided to shut off the master valve after it has dischargedzliquid carbon dioxide for a period which shouldbe sufiicient to extinguifih the. .fire in the particular This is wasteful and in hazard which is being protected. The invention,

therefore, provides means for automatically closing the master valve after a predetermined time interval so that the contents of the supply tank may not be exhausted.

Another feature of the invention is' the provision of an electrical relay which controls the opening and closing of the master valve and which is initiated by an openingmovement of a selector valve.

A further feature of the invention involves the provision of an electrical relay which controls the master valve and which includes a lock-out portion which prevents a repetitive operation of the relay until the selector valve has been closed.

Other features of the invention will be apparent during the course of I the following description when considered with the accompanying draw- 'ings.

In the drawings:

Figure 1 is a schematic representation of afire extinguishing system embodying this invention,

Figure 2 is an elevational view of a selector valve and its associated electrical switch,

Figure 3 is a schematic wiring diagram of a modified electrical circuit, and

Figure 4 is av schematic wiring diagram of another modified electrical circuit.

In Figure 1 three different fire hazards are shown and they are represented by the chambers Hi, H and I2. Each one of these chambers is provided with a discharge orifice or nozzle l3, l4 and 55, respectively, by which the chamber may be flooded with carbon dioxideto extinguish the fire. However, it is to be understood that the invention is not limited in this respect as'more or fewer chambers may be protected by discharge orifices. Moreover, the system may be applied equally as well to hazards which are not in confined spaces, but which are objects subject to fire and which are in the open and upon which the carbon dioxide may be directlyplayed. In addition, the invention is not limited to. the size of the hazard to be protected, but may be applied in any onesystem to hazards of quite different sizes.

The storage tank ii; contains the liquid carbon dioxide which is to be discharged from the orifices 13, M and 15. The carbon dioxide in container It is preferably maintained at a low temperature and its corresponding low vapor pressure, in accordance with the disclosure of the aforementioned patent issued to Eric Geert'z. The invention is not restrictedto. the size of this particular storage tank as. it may be of fairly valve I8.

3 small size only sufficient to effectively handle a single fire or it may be of 'quite large size so that a single fire will only partly exhaust it.

The liquid carbon dioxide in the storage tank I6 is delivered therefrom by means of a di tube or pipe I1 which extends close to the bottom of the tank. The discharge from the dip tube I1 is controlled by a manually operable shut-off valve I8 and also by a master control valve I9 following The manually operable shut-off valve I8 is normally open and is provided for the principal purpose of cutting off the remainder of the system when repairs or changes are to be'made in one of the other valves or the piping.

Valve IBmay be of the type disclosed in detail inFigures 3, 4 and 5 of Patent 2,356,990, issued to Charles A. Getz, on August 29, 1944. The master control valve I9 may be of the type illustrated in Figures 6, 7 and 8 of the aforementioned patent to Charles A. Getz. The master control valve I9 is intended to normally be closed so that it conlines the carbon dioxide in the storage tank I6. It is important, therefore, that this valvel9 be fbubble-tight."

From the master ,control valve I9 leads a header 2| branch pipes 22. The discharge from each branch pipe 22 is controlled by a selector valve 23 each of which passes carbon dioxide to one of the discharge orifices I3, 14 and I5. As the selector valves 23 may be of the same construction, they are given the same reference numeral. The details of the master control valve I9 are Iexplained more fully in the aforementioned patent to Charles A. Getz, but itrmay be. men- 'tioned here that itis opened and closed as a result of the development of differential fluid pressure conditions within its casing. A pilot ,va lve is provided to control this development of differential I fluid pressure" conditions and this pilotvalve is operated by an electrical'contro'l device to Which the lead lines 24 and 25 are con- .nected. When the electrical control device associated with valve I9 is energized by means of the lead lines 24 and 25, the master control valve will be opened. In like manner, when the supply of current by lead lines 24 and 25 is interrupted ,to de-energize the electrical control device, the .valve I9.will move to closed position.

-, As is schematically indicated in Figure l and isshown in somewhat more detail in Figure 2, the selector valves 23in branch pipes 22phave associated therewith an electrical switch 26. The electrical switch 26 is actuated upon manual movement of the valve 23 so that when the valve andconnected to this header are Switches 26 may be supported in the proper position in any desired manner. As here shown, this is accomplished by means of brackets 3I carryin the switches 26 and attached to branch pipes 22.

From the switches 26 extend lead lines 32 and 33 to circuit Wires 34 and 35, respectively. As a consequence, the switches 26 and their lead lines 32 and 33 are in parallel across the circuit wires 34 and 35 so that a connection will be established between the wires 34 and 35 by the opening of any one of the selector valves 23. Circuit wires 34 and 35 could be connected directly to lead lines 24 and 25 of the master control valve [6 with the interposition of a source of electric current so that the master control valve I3 would be under the direct control of the selector valves 23. Howeven'in accordance with the invention,

a relay indicated at 36 is interpositioned between the circuit wires 34 and 35 and the lead lines 24 and 25 so that the master control valve IE3 is under the control of the relay 36.

As willhereinafter appear, the relay 36 serves to directly control the opening and closing of the master control valve I9 and the switches 26 merelv serve to initiate this control exerted by the relay 36. After such initiation of the control exerted by relay 36 by closure of one of the switches 26, the switch 26 is locked out'of the circuitso that the relay 36 completely takes over control and will maintain the master control valve!!! open and will close it aftera predeter-- mined time limit. After the valve I3 has been closed by the relay 36. the relay 36 will continue to,1ock out. theswitches 26 so that a repeated opening ,of the master control valve I6 cannot ':be effected until the closed switch 264s opened tion. To open this closed switch 26, the selector 23 is moved to open position the switch 26 associated therewith is moved to closed position.

;As is shown in Figure 2, the valve 23 is manipu- ,la.ted by means of a handle 21 connected to the valve shaft 28. Attached to this valve shaft 28 is a cam member 29 which is located to contact a push button 36 of the switch 26. When the valve 23 is closed the cam 29 is positioned apart from the contact button 3!! so that the switch 26 is open, but when shaft 28 is turned by handle 21, the cam member 29 is. brought into engagement with the button 36 to close switch 26. It will be appreciated, howev r, that the arrangement shown in Figure 2 will operate satisfactorily if the elements are rever ed. That is, if the switch 26 is of the type which is closed when the button 30 is released and is openedwhen it is depressed, it will be merely necessary to po ition the cam 29 so that it will he in contact with the button 30 when the valve 23 is in closed position.

valve 23 associated with it must be closed.

The electric power input to the relay 36 and the associated electrical circuits is through supply lines 31 and 38. The supply line 38 is connected to the circuit line 34. The other circuit line 35 is connected to the contacts 42 and 43 of a solenoid operated switch 44.

The contact 45 of switch 44 is connected to contact 42 by switch 44 when it is in its lower or normal position, and this contact 45 is joined to a timing device here represented by motor 46. ;The other side of motor 46 isconnected to supply line 31. When one of the contacts 26 is for example, be operated by cams on a shaft, driven at a reduced speed-by motor 46.

Betation of motor 46 will cause these switches to close and, after a predetermined time, to open.

A time cycle controller of the type described above is disclosed in the patent to Joseph H. Staley, No.2.141,024.

Switches 41 and 48 are connected to the electrio input wire 38. The other contact 5| of switch 48 is connected to motor 46 so that when switch 48 is closed by rotation of motor 46, the motor 46 will'be supplied with current through switch 48. The motor will 'be maintained in operation by switch 48, therefore, even though To cause switch 44 to move upwardly and break the connection between contacts .42 and 45, the solenoid 52 which operates switch 44, is Supplied withcurrent by the closure of switch 4?. One side of solenoid 52 is connected to contact 53 of switch 41 and its other .side is .connected to supply line 31. When motor 46 causes switch ,4! to be closed,-solenoid 52 will therefore beenergized and lift switch 44 to break the connection between contacts 42 and 45. This will serve ,to lockout of the circuit the control exer ted by switches 26 over the operation ,of motor 46.

It is desirable that solenoid 52 remain energized to maintain switch 44 in its upper position after switch 47 is opened, in the event that aswitch remains closed. For this purpose switch .44, when it is lifted, closes a connection between contacts 45 and54, the contact 54 being connected to solenoid 52. When switch 26 is initially closed and sets motor 45 in operation, solenoid 52 is thereafter energized by switch 41 as well as .by switch 44 through contacts43 and 54; However, when switch 4? is broken by continued rotation of motor 4-5, solenoid 52 continues to be energized by switch 44 through its contacts 43 and 54 so long as the closed switch 26 remainsclosed.

As long as switch 26 remains closed, therefore, switch 44 will be held up and motor 45 cannot start another operation, as the contacts 42, 45 remain broken. When the closed switch 25 is thereafter opened, due to closure of its associated selector valve 23, solenoid 52 will be de-energized and the switch 44 will fall to connect contacts 42 and 45 sothat the system will be in readiness for the next operation.

Switch .49 is closed when switches 44 and 44 are closed. The switch49 is connected to lead line 24 tomaster valve 19, and its. contact 55 is connected to contact 5i of switch 48. Lead line 25 of master valve i9 is connected to supply line 3?. When switches 48 and 49 are closed, current is then delivered through these switche from supply line 38 to the master valve 19.

Switch therefore, supplies current both to I motor and tomaster valve l9. As the master valve 19 also is controlled b switch 49 it is possible to have the switch 49 opened before the. switch 48 is opened. Thus, by varying the cam which closes switch 49, this switch 49 can be caused to open at a period of time before motor 46 has made the complete cycle necessary to open switch 48 and stop motorfiifi In this way, the period of time that valve I91 is'open, may be varied. I

In the operation of the system, it is intended that an attendant open the proper selector valve 23 when he sees a fire which isto be put out by the discharge orifice Hi to which that selector valve 23 is connected. Such manual opening of the proper selector valve 23 will close the associated electrical switch 26, to close a circuit between the circuit lines 34-and 35. This will serve to start rotation of the motor lfi through the contacts 42, 45 of switch 44. After the actuation of relay 35 has been initiated infthis manner, the relay 35 will take over operation due to the fact that motor 45 will close the switche 4'5, 43 and 49. Closure of switch 48 will maintain energization of motor 46. Closure of switch 4! will energiZe solenoid 52 to lift switch 44 and connect contacts 4 3 and 54. Closure of switch 4!; will supply e e r er t t we rd e te 9 r v f i to thereby effect .its opening movement. l iqi id carbon dioxide willgtherefore, flow through-the .valve J3 through the header 2 I and pass the particular one of the selectorvalves 23'whichfha s been open. I

Valve I 9 will remain open until motor 46 has rotated far enough to cause the Switches '41, 48

and 49 'to open. This 'will break the circuit to the control means of valve 19' so that this-valve will close and shut off the supply of carbon dioxide even though the selector 'valve 23 which was opened remains-open. The relay 3.6 will not, however, cause a repeated opening of valved!) even though the switch 25 is held open by the still open valve 23 because the solenoid 5-2 will remain energized, because the contacts 43 and 54 will be closed as the swit ch 44. is held in an upward position. lI-herefpre, the circuit tothe control means of valve I 9 will remain open until the valve 23 which was open is closed, as thiswill open the associated switch -25 so that the circuit supplying solenoid-52 with electrical energywill be broken. The switch 44 will, therefore, fall and will close the contacts 42 and 45; but motor 45 will not now rotate-because the switches 26 will all be open. When one of the valves 23 is thereafter opened and its associated switch 25 is .closed, the motor 45 will be suppliedwith current through the closed contacts 42 and 45 and the system will operate in the manner which has been described. The circuit of Figure 3 is similar to'that of Figure 1, except that switch 49 has .been eliminated and lead line 24 from the electric control means of master valve I9is connected to contact 45. With this arrangement, current will be'su'pplied directly to the control means of valve I!) by the closure of a switch'26, through closed contacts 42 and 45. As motor 4fiwill at the same time be set into operation, current will continue to be supplied to the control means of valve 19, by the closure of switch 48, and valve [9 will remain open until switch 48 is opened." As with the circuit of Figure 1; switches 26 will be locked out by'switch 44 until the opened selector valve is closed-and switches 26 are all open.

In the circuit of "Figure 4, switch 49 is connected directly to supply line 38- and contact 55 of this switch is connected to lead line 24 of the control means of valve !9. The control means of valve [9 therefore receives current directly from ne 34 h o g c s d sw h 4 t adf through both switche 48 and 43 as in the, circuit of Figure 1. With this circuit of Figure 4, the time that valve 19 is open may be varied by changing the cam which controls switch 49.

. WhatI claim is:

l. "A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from thetank, a master valve for controlling the flow of carbon dioxide through the. discharge pipe, a header connected to the outlet of the master valve, '2. separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be manually opened and, closed for controlling each branch pipe, electrical means operable in response to the opening operation of any selector valve while the remaining valves are closed for effecting opening operation-of the master valve, means for effecting closure of the master valve a e a p ed erm n d t m er al irres ectiv while any of the selector valves are open.

- 2. 'Affire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be manually opened and closed for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operated upon manipulation of the selector valve, an electric connection between said electrically operated means and said circuit controlling means to' efiect opening of the master valve when one of the selector valves is opened while the remaining valves are closed, said connection including a timing device for limiting the time period that the master valve remains open although the selector valve remains open for a longer period of time, and means for breaking .said electric connection to prevent reopening of the master valve while any of the selector valves are open.

3'. A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected opened and closed manually for controlling each branch pipe, electrically operated meansassociated with said master valve and which when energized will effect opening of the valve, an electric switch associated with each selector valve to be closed upon opening of the selector valve, and an electric connection between said electrically operated means and said electric switches to cause opening of the master valve when one of said switches is closed by opening movement of a selector valve while the remaining valves are closed, said connection including means to break the electrical connection after a predetermined time interval to thereby deenergize said electrically operated means and effect closure of the master valve although the selector valve remains open for a longer period of time, and means to prevent the reclosing of said electrical connection and the reopening of said master valve while any of the selector valves are open.

' through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means asopening of the master valve when one or the selector valves is manually opened while the otherselector valves remain closed, said connection including a relay responsive to said circuit controlling means and controlling current flow.

to said electrically operated means, and said relay including means for taking over control of current flow to the electrically operated means and eliminating control by said circuit controlling means to efiect closing of the master valve after a predetermined time interval even though the selector valve remains open for a longer period of time, and means for maintaining control of said current flow by said relay to prevent reopening of said master valve while any of the selector valves are open.

5. A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the'flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, an electric circuit for said sociated with each selector valve to be operated upon opening of the selectorvalve, and an electric connection between said electrically operated means and said circuit controlling means to effect electrically operated means including a timing device for maintaining the master valve open a predetermined time and then effecting its closure, means operated by opening of one selector valve 7 while the remaining valves are closed for initiating the functioning of said electric circuit, and means to prevent the refunctioning of said electric circuit to reopen said master valve while any of the selector valves are open.

6. A fire extinguishing system for protecting a plurality of separate hazards, comprisinga storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header a selector valve adapted'only to be opened manually for controlling 7 each branch pipe, electrically operated means associated with said master valve for effecting opening of that valve when the electrically operated means is energized, an electrical circuit for energizing said electrically operated means and including timing means for deenergizing the electrically operated means after a predetermined time to eiTect closure of the master valve, means operated by opening operation of one selector valve while the remaining valves are closed for initiating the functioning of said electric circuit, and means to prevent the reenergizing of the electrically operated means to reopen said master. valve while any of the selector valvesfare open. 7

7. A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operateduponopening of the selector valve,'and an" electric connection between said electrically operated means and said circuit control means to eiiect opening of the master valve when one of the selector valves is opened while the other valves remain closed, said connection including a timing device for limiting the-time period that the master valve is open and also including means for breaking the connection tosaid circuit controlling means' to prevent reopening of said'master valve while'any of the selector valves are open.

8.. A1 fire extinguishing' system for protecting a plurality'fof separate hazardsfcomprising a storage tank for supplying liquid carbon dioxidraa discharge pipe extendingfrom the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operated upon opening of the selector valve, and an electric connection between said electrically operated means and said circuit controlling means to effect opening of the master valve when one of the selector valves is opened while the other valves remain closed, said connection including a relay responsive to said, circuit controlling means and controlling current flow to said electrically operated means, said relay including a timing device to limit the time period that the electrically oper ated means functions to hold the master valve in its open position, and said relay including a solenoid operated switch which in normal position closes a circuit from the circuit control means to said timing device and which in its abnormal position opens the circuit from the circuit control means to said timing device and closes a circuit from the circuit controlling means to the solenoid to retain the switch in its abnormal position while any of the selector valves are open.

9. A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operated upon openin of the selector valve, an electric connection between said electrically operated means and said circuit controlling means to elfect opening of the master valve when one of the selector valves is opened while the other valves remain closed, said connection including a relay responsive to said circuit controlling means and controlling current flow to said electrically operated means, said relay including a timing device to limit the time period that the electrically operated means functions to hold the master valve in its open position, said relay further including a solenoid operated switch which 10 inno-r mal position closes a circuit from the cir-l cuit control means to said timing device and which in itsabnormal position opensthe circuit from the circuit control means tosaid timing devipe'and closes acircuit from the circuitpontrolling' means" to the solenoid to retain th'e switch in it'sgabnormal position while any of the selector valves are'bpen; and said relay also including a switch: by operation of said timing device toen'ergize the solenoid and thereby eliminate control of the relay by said circuit controlling means"; I

l0. fire extinguishing system for protecting a' plurality of separate hazards, comprising a storagetank for supplying liquid carbon dioxide, a dis chari'ge pipeextend ing from the tank, a mas: ter valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operated upon opening of the selector valve, an electric connection between said electrically operated means and said circuit controlling means to effect opening of the master valve when one of the selector valves is opened while the other valves remain closed, said connection including a relay responsive to said circuit controlling means and controlling current flow to said electrically operated means, said relay including a timing device to limit the time period that the electrically operated means functions to hold the master valve in its open position, said relay further including a solenoid operated switch which in normal position closes a circuit from the circuit control means to said timing device and which in its abnormal position opens the circuit from the circuit control means to said timing device and closes a circuit from the circuit controlling means to the solenoid to retain the switch in its abnormal position while any of the selector valves are open, and said relay also including a switch to continue the operation of the timing device once it has been initiated by retaining said solenoid operated switch in its abnormal position until the predetermined time period has elapsed.

ll. A fire extinguishing system for protecting a plurality of separate hazards, comprising a storage tank for supplying liquid carbon dioxide, a discharge pipe extending from the tank, a master valve for controlling the flow of carbon dioxide through the discharge pipe, a header connected to the outlet of the master valve, a separate branch pipe line extending to each hazard from the header, a selector valve adapted only to be opened manually for controlling each branch pipe, electrically operated means associated with said master valve for controlling its opening and closing operations, a circuit controlling means associated with each selector valve to be operated upon opening of the selector valve, an electric connection between said electrically operated means and said circuit controlling means to effect opening of the master valve when one of the selector valves is opened while the other valves remain closed, said connection including a relay responsive to said circuit controlling means and controlling current fiow to said electrically operated means, said relay including a timing device to limit the time period that the electrically 1 l operated means functions to hold the, master valve in its open position, said relay further including a solenoid operated switch which in normal position closes a circuit from the circuit control means to said timing device and which in its abnormal position opens the circuit from the circuit control means to said timing device and closes a circuit from the circuit controlling,

means to the solenoid to retain the switch in its abnormal position while any of the selector valves are open, said relay also including a switch closed by operation of said timing device to energize the solenoid and thereby eliminate control of the relay by said circuit controlling means, and another switch to continue the operation of the timing device once it has been initiated by retaining said solenoid operated switch in its abnormal position. until the V predetermined time,

period has elapsed.

' WALTER A. BEACH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 506,700 Kiehl -2 Oct. 17, 1893 777,888 Fidder Dec, 20, 1904 2,111,019 Allan Mar. 15, 1938 2,141,024 Staley Dec. 20, 1938 2,185,394 Arbogast Jan. 2, 1940 2,341,437 Getz Feb. 8, 1944 2,356,990 Getz Aug. 29, 1944

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