US2356990A - Fire extinguishing system - Google Patents

Description

Aug. 29, 1944- c. A. GETZ I 2,356,990

FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 s Sheets-Sheet 1 Zarl esA deix Aug. 29, 1944. c. A. GETZ FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 8 Sheets-Sheet 2 c. A. GETZ 2,356,990

FIRE mx'rmeuxsnme SYSTEM Filed Nov.- '28, 1942 a Sheets-Sheet 5 Aug. 29, 1944.

Aug. 29, 1944. c. A. GETZ FIRE EXTINGUISHING SYSTEM Filed NOV. 28, 1942 8 Sheets-Sheet 4 fla rlesd- Gale Aug. 29, 1944. c, 5 2

FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 8 Sheets-Sheet 5 ZazlesA fieiz Aug. 29, 1944. c. A. GETZ 2,356,990

I FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 V 8 Sheets-Sheet 6 Aug. 29, 1944. c. A. GETZ FIRE nxwmauxsnme SYSTEM Filed Ndv. 28. 1942 a Sheets-Sheet '7 Aug. 29, 1944. GETz 2,356,990

FIRE EXTINGUISHING SYSTEM Filed NOV. 28, 1942 8 Sheets-Sheet 8 Elma/whom flax/21A dale Patented Aug. 29, 1944 FIRE EXTINGUISHING SYSTEM Charles A. Getz, Glen Ellyn, IlL, assignor, by mesne assignments, to Reconstruction Finance Corporation, Chicago, Ill., a corporation of the United States Application November 28, 1942,

23 Claims.

This invention relates to new and useful improvements in ilre extinguishing systems and deals more particularly with systems that employ liquid carbon dioxide as the extinguishing medium. and rate of discharge; and which may employ A relatively recent innovation in carbon dioxide any total footage of piping that is required to fire extinguishing systems involves the use of a serve either a remotely located hazardor a numcentrally located, insulated tank for confining ber of closely grouped independent hazards, all liquid carbon dioxide at a controlled subatmoswith a minimum amount of trouble caused by pheric temperature and its corresponding low leakage, trapping of extinguishing medium in vapor pressure; suitable piping for conducting portions of the piping, etc. the liquid carbon dioxide to the several hazards A further object of the invention is to provide that are to be protected, and a suitable number a fire extinguishing system in which the flow of of valves for controlling the flow of the liquid the extinguishing medium from the central from the central tank to the one or more hazards source of supply to a hazard is controlled by at that are to be protected. least two normally closed valves which are ar- Systems of this type may require the use of ranged in series in the piping with one valve either a few hundred pounds or several tons of located relatively close to the source of supply the liquid carbon dioxide to provide adequate so as to normally exclude the high pressure liquid protection for the hazards, and an adequate rate from the piping and with another valve located of discharge of the extinguishing medium may adjacent the hazard to control the actual startinvolve from a few hundred pounds to several ing and stopping of the application of the extons per minute. The largest tank thus far intinguisher to the fire. To prevent liquid carbon stalled for confining liquid carbon dioxide at a dioxide from being permanently trapped in the constant low temperature and pressure has a piping between the respective valves of such a storage capacity of 125 tons and the highest rate series, which trapping would result in the deof discharge that has been found to be necessary velopment of a high vapor pressure in the pipfor a single hazard is six tons per minute. 00- ing due to the absorption of heat by the liquid casionally a situation will be encountered which carbon dioxide, all valves located upstream from makes it necessary to locate the central supply the outermost one are of a construction which tank several hundred feet from at least one will permit trapped liquid carbon dioxide to flow hazard and, of course, a pipe line must be ex back to the'source of supply whenever such uptended from the tank to the hazard to carry the stream valves are subjected to apressure on their liquid carbon dioxide. Almost every system that outlet sides which exceeds the pressure on their provides protection for several independent hazinlet sides. ards requires the use of several hundred feet of Still another object of the invention is to empip ng to properly connect up all of the hazards ploy a series of flow controlling valves which are with the carbon dioxide supply tank. adapted to be opened and closed by the con- It will be apparent from what has been stated trolled application of differential fiuld pressures, above that fire extinguishing systems of this type 40 and with the downstream valve or valves of the may very readily involve the handling of large series being so constructed that they will not be quantities of liquid carbon dioxide under vapor caused to open prematurely or unintentionally pressures of several hundred pounds per square in response to the sudden surge or rush of fluid inch at rapid rates of discharge through relativethat is caused by the opening of the next adjaly large diametered pipes which extend a total cent upstream valve. of several hundred feet. Handling conditions of Other objects and advantages of the inventhis character must necessarily present troubletion will be apparent during the course of the' some problems with reference to pipe joint and following description. valve leakage, strength of piping required, trap- In the accompanying drawings forming a part ping of portions of the extinguishingliquid in of this specification and in which like numerals certain sections of the piping after a discharge are employed to designate like parts throughout at a given hazard or other operations of the systhe same, tern, etc. Figure 1 is a diagrammatic view of the type of It is the primary object of this invention to carbon dioxide fire extinguishing system embodyprovide a form of fire extinguishing system which ing this invention,

Serial No. 467,191

may be constructed and installed at acomparatively low cost; which may be adapted for handling either large or small quantities of liquid carbon dioxide at any desired vapor pressure of this invention,

Figure 2 is a perspective view of a liquid carbon through the valve structure of Figs. 3 and 4,

Figure 6 is a vertical sectional view of the master control valve employed in the system of Fig. 1 and a pilot valve which is employed for controlling the application of difierential fluid pressures to the master control valve to effect opening and closing operations 01' the latter,

Figure '7 is an elevational view of the pilot valve of Fig. 6 with an electric solenoid which is employed for operating the pilot valve,

Figure 8 is a sectional view taken on line 8-8 01' Fig. 7,

Figure 9 is a vertical sectional view of a selector valve employed in the system 01' Fig. 1;

Figure 10 is a detail sectional view taken on line ill-l of Fig, 6,

Figure 11 is an elevational view of a modified form of pilot valve and its actuating mechanism which may be employed for controlling the application of operating fluid pressures to the master controlvalve and the selector valves,

Figure 12is an end elevational view oi the mechanism shown in Fig. 11, and

Figure 13 is a detail sectional view taken on line l3-l3 of Fig. 11.

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments and first particularly referring to Fig. 1, there are shown two different fire hazards which are to be given fire extinguishing system that embodies this invention. These hazards are designated by the reference characters A and B. As illustrated, they consist of enclosed spaces or rooms, but it is to be undertsood that this system is not limited in its use to the protection of this type ofhazard. The extinguishment of fires in enclosed spaces is thus accomplished with carbon dioxide by totally flooding the spaces; i. e., building up a concentration of carbon dioxide vapor which will not support combustion. By employing different types or sizes and different arrangements of discharge devices, all types and kinds of hazards may be fully and adequately protected by the illustrated system. It will be noted that hazard A is larger than hazard B. This type of illustration is provided to show that the system is of such a flexible character that it can be employed for eilectins extinguishment of diiferent sized fires and for protecting hazards which require different amounts of the extinguishing medium.

In the diagrammatic showing of Fig. l, the reference character I is employed to designate the source of supply of liquid carbon dioxide. Because oi. the advantages to be obtained, it is preferred that'this source of supply take the form of a single insulated tank in which the liquid carbon dioxide is stored and is maintained at a desired, constant subatmospheric temperature and its corresponding low vapor pressure. It is to be protection by the satisfactoiily if the liquid carbon dioxide is confined in either an uninsulated storage tank or proper capacity or uninsulated cylinders and with no means employed for maintaining the liquid at any constant, controlled temperature. It the liquid is to be obtained from a bank of cylinders, the usual practice of employing separate discs and cutter devices for each cylinder should be dispensed with and all of the cylinders should be placed in open communication with a manifold so that the flow of the carbon dioxide can be controlled by the valves of this system.

The source of supply of liquid carbon dioxide I! should be adequate to afiord the desired protection for the hazards A and B. The amount of liquid carbon dioxide may be sufllcient for providing the following types of discharges:

l. A single discharge that will effect extinguishment of fires in each one of the two hazards A and B with no reserve for extinguishing a fire in either hazard in case 01 a reflash.

2. A two shot discharge for either one 01 the two hazards which will effect extinguishment 01 a fire and will extinguish any refiash that may occur.

3. A two shot" discharge for both of the hazards.

understood, however, that the system will operate Although the fllustration provided by Fig. 1 shows only two hazards being protected, it will be appreciated that any desired number of hazards may be taken care 01' by merely extending the illustrated system. It, also, should be understood that this type of system has been found to be very effective and eflicient in protecting a single hazard which must be located a considerable distance from the nearest place at which the source of supply may be positioned.

The liquid carbon dioxide is withdrawn from the source 01' supply I! by means of a dip-tube it that extends out of the storage tank, or the like, for connection with the inlet side of the shutofl' valve IT. The outlet side of this valve i1 is connected by the pipe section It to the inlet side of the master control valve I9. When the system is in normal operating condition, the shutofl' valve l1 stands open while the master control valve i9 is closed. The release or discharge of the carbon dioxide from its source, therefore, is normally controlled by the master valve l9.

This master control valve i9 is intended to respond to the creation of certain fiuid pressure conditions within its housing. That is to say, the master control valve will be opened as a result of the creation of one fluid pressure condition within its housing and it will be closed as a result of the creation of a different fluid pressure condition. These changes in fluid pressures are accomplished by means 01 an electrically controlled pilot valve unit 20 that is connected to the pipe line i8 by the tubing 2i and is connected to the master control valve housing by the tubing 22. Circuit wires 23 and 24 extend from the electrical control portion of the pilot valve unit 20 to the electric control box 25.

With the master control valve I! normally closed, the remainder of the piping of the system will not be subjected to the pressure of theliquid carbon dioxide except when the system is placed in operation to effect extinguishment of a. fire in one or more of the hazards. Therefore, there is provided a non-pressure header 26 beyond the master control valve 18 which is connected to the various independent branch lines 21 that extend to the different hazards. Each one 01' these the extinguishing medium from branch lines has connected therein a selector valve 28 which functions to controlthe fiow of the header 28 through a branch line 21 to the discharge device 28 which is properly associated with the hazard that is served by a given selector valve and its branch line. It will be noted that the discharge devices 28 are of different sizes for the two hazards A and B. By employing different sized discharge devices, different amounts of carbon dioxide may be delivered to the different sized hazards during a given discharge period. That is to say, different sized discharge devices 28 provide different rates of release so that a smaller discharge device will effect delivery of a smaller amount of carbon dioxide during each minute of discharge than a larger device.

The selector valves 28 are intended to be conitrolled by the same type of pilot valve and electric control unit as are used by the master control valve is and for that reason the same reference characters will be applied. Circuit wires 38 and Si extend from the electrical portion of each pilot valve unit for each selector valve to the electric control box 28.

Although no attempt has been made to illustrate the feature in the diagrammatic showing of Fig. l, the header 28 and the portions of the branch lines 21 that are arranged upstream with respect to the selector valves 28 should be inclined or otherwise suitably arranged so that any liquid carbon dioxide that may be trapped between the master control valve l8 and the selector valves 28 may drain back to the source of supply l5. The short pipe section l8 and the dip-tube 16, also, should be arranged so as to permit the return of liquid to the source of supply 15. Gravitational flow of this liquid is all that is ordinarily required to effect this return movement of the liquid. When the detail features of construction of the shut-off valve l1 andmaster control valve l8 are explained in connection with otherfigures .of the drawings, it will be shown how this liquid carbon dioxide will be permitted to return to the source of supply. It will be explained at this time, however, that this return of trapped liquid results from the building up of a predetermined vapor pressure within theportions of the piping located between the valves that create the trapped conditions. This building up of vapor pressure results from the absorption of heat by the trapped liquid and the vaporization of a portion of the liquid. The greater the amount of heat absorbed by the liquid, the greater the amount of liquid that is vaporized. The liquid naturally will occupy the lower portion of the piping in which it is trapped while a vapor space will be formed in the upper portion of the piping. A vapor operated whistle 32 is connected to the header 28 at a suitable high point which will receive the carbon (11-. oxide vapor. This whistle may be of any suitable construction, such as a centrally apertured wafer or peanut venders whistle, which will be operated as carbon dioxide vapor is slowly bled therethrough. This whistle will function to indicate to an attendant that liquid carbon dioxide is trapped in the header 28. It, also, will function to bleed off all of the vapors that remain after the liquid has been returned to the source of supply IS. It will be apparent, therefore, that the header 28 will again be returned to its non-pressure condition.

The two hazards A and B are each provided with a suitable number of circuit closing, fire detecting devices 33. The fire detecting devices for each hazard are connected in parallel with the circuit wires 38 and 35 which extend to the electric control box 25. It will be understood that each one of these fire detecting devices 33 will be capable of closing the circuit between its two wires 3| and 35 when said device is subjected to a certain degree of temperature, or a certain rateof-rise of temperature as a result of the presence of a fire in the hazard that is protected by the detecting device. Each one of the two fire detecting circuits may be closed by a manual switch 38 which may be located at any desired point relative to its hazard.

Electricity is supplied to the control box 25 by means of the two power lines 31 and 38, the double-pole, single-throw switch 39 and the wires 40 and 4!.

The operation of the system diagrammatically illustrated in Fig. 1 now will be explained. Whenever a fire occurs in either one ofthe two hazards protected by the system, its existence will be detected by one of the devices 33 and this device will operate to close the circuit through its wires 34 and 35. If the existence of a fire is observed by some person before one of the automatic detecting devices 33 is operated, the circuit through the wires 34 and 35 may be closed by the appropriate manually operable switch 38. The closing of one of the detector circuits will start in motion the electric control mechanism confined in the control box 25. This mechanism will operate to first close the circuit to the electric portion'of the pilot valve unit 28 for the master control valve I9 through the wires 23 and 24. A circuit will also be closed to the electrical portion of the pilot valve unit 20 which is associated with the selector valve that controls the delivery of carbon dioxide to the particular hazard that is involved. The closing of the circuits to the two pilot valve units 20 will create fluid pressure conditions in the housing of the master control valve l9 and the housing of the proper selector valve 28 for causing these two valves to open. The liquid carbon dioxide will then flow from the source of supply l5 through thedip-tube IS, the short pipe line l8, the header 2G and the proper branch line 21 to the discharge device 29 and will be released by this discharge device into the proper hazard.

By employing a time cycle controller of the type disclosed in the patent to Joseph H. Staley, No. 2,141,024, in the electric control box 25 for timing the opening and closing operations of the circuits 2324 and 3ll--3l -to the pilot valve units of the master control valve l9 and the proper selector valve 28, the lenth of time these valves stand open may be controlled. As the rate of discharge of carbon dioxide to a hazard may be controlled by the capacity of its discharge device 28, or by the fiow capacity of the branch line 21 and/or the selector valve 28, a predetermined amount of carbon dioxide will be delivered to a particular hazard whilethe master control valve and the selector valve stand open. After the elapse of the proper discharge period, the master control valve andthe actuated selector valve will be closed automatically. This control and two additional discharges for the second hazard.

After the master control valve I 9 and the actuated selector valve 28 are closed, liquid carbon dioxide will be trapped in the header 26 and both of the branch lines 21 up to the selector valves 28. As pressure develops in the piping by the absorption of heat by the trapped liquid, the master control valve l9 will open to permit the liquid to drain back into the source of supply I5. The whistle 32 will function to serve notice that liquid carbon dioxide is trapped in the header and it will also function to vent the carbon dioxide vapor that remains after the liquid is drained back into the source of supply.

The shut-off valve I1 is normally locked open. However, this valve may be manually closed whenever it is necessary to test, adjust or repair any of the piping or the control instrumentalities of the system. If the closing of this shut-off valve results in trapping liquid in the pipe section I8, the shut-off valve I! will function to permit this trapped liquid to drain back into the source of supply l so that an excessive pressure will not develop in the pipe l8.

It was explained above that the source of supply of liquid carbon dioxide I5 preferably should take the form of a single, insulated storage tank in which the liquid carbon dioxide was maintained at a predetermined, constant, subatmospheric temperature, and its corresponding low vapor pressure, by means of a suitable refrigerating device although the source of supply might take the form of a bank of high pressure cylinders. Fig. 2 discloses the preferred type of supply unit. It includes a tank 42 which is surrounded by suitable insulating material and is confined within a suitable housing 43. The end portion 43a of this housing forms a chamber in which is located a suitable mechanical refrigerator unit of conventional design. No attempt has been made to disclose such a unit but it is provided with a condenser coil 44 which is located in the vapor space of the tank 42 and functions to condense the carbon dioxide vapor and cause it to drop into the body of liquid confined in the liquid space of the tank. The mechanical refrigerator unit is ventilated by suitable grill panels 45 which are located in opposite side walls of the end compartment 43a.

A suitable instrument panel 46 is mounted in the end wall 41 of the housing and includes a liquid level gage 48, a pressure gage 49 and a pressure control switch 50. The liquid level gage 48 functions to indicate the amount of liquid present in the tank 42. The pressure gage 49 functions to give a visible indication of the pressure that prevails within the tank 42. The pressure control switch 50 operates in response to pressure changes within the tank 42 to control the operating periods of the mechanical refrigerating device located in the end compartment 43a.

When the supply of liquid carbon dioxide for the tank 42 is to be replenished, a transportation truck or railway tank car is employed for carrying the low temperature and pressure liquid carbon dioxide to the location of the storage unit l5. The liquid space of the transport unit is connected to the bottom of the tank 42 by means of the pipe 5| while the vapor space of the transport unit is connected to the upper portion of the storage tank 42 by means of the vapor pipe 52. These two connections will function to equalize the vapor pressures existing in the transport tank and the storage tank. It willbe noted that the vapor line 52 extends a certain distance into the tank 42. This vapor line should extend about one-seventh of the internal diameter of the tank 42 and thereby function to prevent the tank from being filled with liquid beyond six-sevenths of its depth.

A pipe 53 is connected to the top of the tank 42 and extends outside of the housing 43 for connection with the safety head assembly 54. This assembly includes two direct spring-loaded pop valves 55 which are set to open and bleed oil carbon dioxide vapor whenever the pressure in the tank 42 rises to a certain value above the desired maximum pressure that is intended to be maintained by the mechanical refrigerator unit. In other words, should the mechanical refrigerator unit fail to operate to hold the vapor pressure within the tank 42 at the desired working pressure and the pressure is caused to rise to the operating pressure of the valves 55, due to the input of heat through the tank insulation, these valves will open to vent carbon dioxide vapor. This release of vapor from the tank will cause a proper amount of the liquid to vaporize and thereby bring about a self-cooling or refrigerating action which will lower the temperature of the remaining liquid. The safety head assembly 54 also includes a frangible or rupturable disc unit 56 which will blow out at a predetermined pressure that is above the operating pressure of the relief valves 55 but below the maximum pressure at which the tank 42 has been tested to determine its maximum safety pressure.

The tank shut-oil valve I! will be described in detail in connection with the disclosures of Figs. 3 to 5 inclusive. This is a manually operable gate valve which includes the body 51 that is suitably threadedly connected at its inlet side 58 to the upper end of the dip-tube I6. A nut 59 is threaded in the opening 60 of the body 51 and provides a coupling for connecting the discharge side of the valve to the pipe section It that extends to the master control valve. This nut 59 also functions to provide a seat 6| for the valve disc 62 to engage. This valve disc 62 is attached to the disc carrier 63 by the telescopic joint 64 which permits the valve disc to partake of axial movement relative to the carrier 63. A compression spring 65 is interposed bevalve disc in the direction of flow 01 fluid through the valve body. An opening 66 is also formed in the portion of the valve disc carrier 63 which overlies the rear or upstream side of the valve disc. This opening functions to admit the liquid carbon dioxide to the rear face of the valve disc 62 so that the pressure of the liquid will cooperate with the load provided by the spring 65 for retaining the valve disc 82 in tight engagement with its seat 6|.

A rotatable stem 61. extends through a bushing assembly 68 that is mounted in one side wall of the housing 57. This stem is suitably attached to the valve disc carrier 63 so that rotation of the stem will cause the carrier to be moved to either seat or unseat the valve disc 62, depending upon the direction of rotation of the stem 61.

The outer end of the stem 61 has suitably splined or keyed thereon the worm wheel sector 89 which meshes with the worm gear 10 that is carried by the worm shaft 1| joumaled in the mounting or bracket 12 carried by the valve housing 51. The worm shaft 1| is illustrated in Figs. 3 and 4 as having a hand wheel 13 mounted on one end thereof. Manual operation of this wheel will accomplish opening and closing movements of the valve disc 82.

The worm wheel sector 69 has the words "open" and closed' suitably applied thereto. These words are intended to cooperate with the fixed I pointer I4 for indicating the positions of the valve disc 92. The worm wheel sector 69 also is provided with an apertured keeper I 5 which cooperates with a similar keeper I8 that is suitably attached to the worm shaft supporting bracket or mount I2. The apertures of these two keepers. I5 and 18 will register when the pointer 14 registers with the word "open so that a padlock may be used to hold the worm wheel sector 88 in this position. This locking mechanism functions to prevent unauthorized closing of this shut-off valve I1.

Fig. 5 shows the valve disc 82 in engagement with its seat 8|. As this tank shut-off valve is normally open, carbon dioxide is normally present in the dip-tube I6 and the pipe section I8. The master control valve I9, see Figs. 1 and 2, is normally closed for preventing the carbon dioxide from flowing into the header 26. Therefore, whenever the shut-off valve I1 is closed, carbon dioxide will be trapped in the pipe section I8. As this trapped carbon dioxide is isolated from the carbon dioxide in the tank 42, its temperature and pressure conditions will not be controlled by the mechanical refrigerator unit that is connected to the tank and the input of heat through the wall of the pipe I8 will cause the pressure of this trapped carbon dioxide to rise. When th pressure of this trapped carbon dioxide exceeds the pressure applied to the rear face of the valve disc 62; i. e., the pressure developed by the carbon dioxide in the dip-tube I6 and the valve disc loading spring 65, the valve disc 82 will be unseated and thereby balance the pressure in the dip-tube I6 and the pipe I8. It will be appreciated, therefore, that this yieldably seated valve disc 82 will permit liquid carbon dioxide to be returned to the tank 42 and will function to prevent the building up of an excess pressure in the pipe section I8.

The master control valve is disclosed in detail in Figs. 6 and 10. The valve casing I1 is of hollow construction to provide an inlet pressure chamber is with a power cylinder 19 overlying the chamber and in fully open communication therewith. The inlet side of the casing 11 is suitably constructed at 80 to be connected with the pipe section I8 in the manner illustrated. The outlet side of the valve casing I1 is provided with an opening 8I adapted to receive the member 82 that is shaped to provide a valve seat 83. This member 82 is flanged at. 84 to accommodate the threaded securing studs 85 by means of which the member 82 is secured to the valve casing TI.

tion of this extension will be explained at a later point. The cover plate is recessed or pocketed at 8| to receive. the upper end portion of the coil spring 92 when the spring is expanded. This recess or pocket 9| also functions as a part of a nesting space for the spring when the latter is compressed as a result of opening operation of the valve. The recess or pocket 9| is tapped at 93 to receive the coupling sleeve 94 by means of which the tube 22 is connected to the valve casing I1.

This member 82 functions as a coupling be- I tween the valve casing 11 and the pipe header 26 by being thieadedly connected at 89 to said header. A gasket 81 is provided to prevent leakage between the valve casing I1 and the header The upper open end of the power cylinder I9 is adapted to be closed by the flanged cover plate 88 which is secured in place by the studs or screws 89. A packing gasket 90 is interposed between the cover plate 88 and the upper end of the valve casing to prevent leakage between these two mem bers. It will be noted that this gasket 90 extends inwardly of the power cylinder wall. The func- This master control valve is provided with a valve disc that has the seating washer 99 se cured thereto by means of the retainer 81. This seating washer 96 is formed of any suitable material, such as a synthetic rubber that will withstand low temperatures. A valve disc carrier 98. which takes the form of a bell crank lever} is pivotally connected to the back of the valve disc 95 by means of the pin 99 which passes through the apertured ears I00 that are formed on the back of the disc. The end portion of the carrier 98 which is pivotally connected to the valve disc 96 is provided with shoulders IOI which are spaced a suitable distance from the rear face of the valve disc 95 to allow for a limited amount of pivotal movement between th valve disc and its carrier 98. This clearance allows for just sufficient action of the valve disc to assure an even distribution of pressure on the valve seat 93 by the top and bottom portions of the disc. This slight pivotal movement of the valve disc relative to its carrier also provides uniform seating in case the valve disc washer 96 becomes permanently compressed.

The remaining end of the bell crank lever type of disc carrier 99 is pivotally connected to the valve casing 11 by means of the hinge pin I02. This type of carrier mounting for the valve disc will permit the valve disc and its seating washer to swing open against the direction of flow of fluid through the valve casing and into a position where the valve assembly will not obstruct the path of flow of the fluid. In other words, the valve, when fully opened,will provide a straightthrough flow for the fluid which will not be obstructed by the valve and will not provide any appreciable pressure drop.

A power piston I03 is positioned in the power cylinder 19 and is provided with a bifurcated piston rod I04 that i pivotally connected to the intermediate or elbow portion of the bell crank lever valve disc carrier 98 by means of the piston pin I05. The power piston I03 is substantially cup-shaped to provide the pocket or recess I06 for receiving the lower end portion of the spring 92. This pocket or recess I06 cooperates with the pocket or recess 9| of the cover plate 88 for completin the nesting space for the coil spring 92' when the power piston I03 is moved upwardly as far as possible. The power piston body is provided with a top flange I01 which is tapered or beveled at its periphery I08 to permit the power piston to partake of a tilting motion when the piston moves through the power cylinder. This tilting motion prevents binding of the piston in the cylinder and is made necessary by the fact that no lost motion or play is allowed between the piston pin I05 and either the bifurcated piston rod I04 or the valve disc carrier 98.

Figs. 6 and 10 disclose a cup-leather I09 for packing between the power piston I03 and the wall of the power cylinder 19. This cup-leather I09 constitutes the main bearing for the power steel strips and the cup-leather I09 are clamped against the bottom face of the flange I01 of the power piston by the retaining ring III which is threadedly mounted on the periphery of the cupped body portion of the power piston I03.

It was explained in connection with the disclosure of Fig. 1 that a pilot valve unit 20 was employed for creating suitable pressure conditions within the valve casing 11 to accomplish opening and closing operations of the valve. This pilot valve unit controls the flow of carbon dioxide from the pipe section I8 through the tubes 2| and 22 into the power cylinder I9. That is to say, when the pilot valve is in its normal condition of operation the tubes 2I and 22 will be placed in communication with each other and carbon dioxide will flow from the pipe I8 into the power cylinder I9. The pilot valve unit 20, however, is capable of being conditioned so that flow of carbon dioxide through the tube 2| will be stopped and the power cylinder I9 will be placed in communication with the atmosphere, or the carbon dioxide pressure developed in the cylinder I9 will be vented to the atmosphere to reduce the pressure in this power cylinder below the pressure prevailing in the pipe section I 8 and the inlet pressure chamber I8.

Let us now consider that no fluid is present in the pipe section l8 or in any portion of the valve casing. When this condition exists, the valve disc will be seated and retained in that position solely by the load imposed on the power piston I03 by the spring 92. Let us now consider that carbon dioxide is admitted to the pipe I8 and that the pilot valve unit 20 is in its normal or open position so that the tubes 2| and 22 are placed in communication with each other. When this condition prevails, the same fluid pressure is developed in the inlet pressure chamber I8 and the power cylinder 19 so that the same pressure is applied to both faces of the power piston I03. As the fluid pressures on the opposite sides of the power piston are equalized, the valve disc 95 will be held closed or in its seated position by the pressure of the spring 02 and by the application of fluid pressure to the back or upstream surface of the disc 05.

When it is desired to cause the valve to open,

the pilot valve unit 20 is actuated to close the tube 2I and to vent the tube 22 to the atmosphere. This venting of the tube 22 also vents the power cylinder I8 so that atmospheric pressure prevails in this cylinder. The fluid pressure of the carbon dioxide in the inlet pressure chamber I8 will then be applied to the inner face of the power piston I03 and, of course, still to the upstream face of the valve disc 95. The fluid pressure applied to the inner face of the power piston I 03, therefore, opposes the load provided by the spring 92 and the fluid pressure applied to the back or upstream face of the valve disc 95. The area of the inner face of the power piston relative to the area of the upstream face of the valve disc 95 is such that substantially a two-to-one pressure ratio is provided in favor of the power piston. This differential fluid pressure in favor of the power piston will cause the latter to move upwardly through the power cylinder I9 to efiect opening movement of the valve disc 95. This upward movement of the power piston is limited by sealing engagement of its flange I01 with the inwardly projecting portion of the packing gasket 90. This sealing engagement of the power piston with the packing gasket supplements the sealing action accomplished by the cup-leather I00, while atmospheric pressure prevails in the power cylinder I0, to prevent any leakage of carbon dioxide into the space formed by the spring receiving pockets or recesses 9| and I08. If liquid carbon dioxide were permitted to pass into this.

vented space, the resulting pressure drop would cause the liquid to flash to a mixture of carbon dioxide snow and vapor. The snow would be likely to plug up or close the passage through the coupling 94 and the tube 22 and cause pressure to build up above the power piston which would bring about a premature closing of the valve.

When it is desired to again close or seat the valve disc 95, the pilot valve unit 20 is operated to prevent venting of the tube 22 to the atmosphere and to again connect the tube 2| with the tube 22. Pressure will then be built up in the power cylinder I8 until the pressure in this cylinder equalizes the pressure in the inlet chamber 18. The spring 92 and the fluid pressure applied to the valve disc 95 will then cause the valve disc to be closed or seated.

The drawings disclose two different types of pilot valve units 20 for controlling communication between the tubes 2| and 22. One form of unit is disclosed in Figs. 6 to 8 inclusive. The other form is disclosed in Figs. 11 to 13 inclusive. The principal difference between these two types of units is that the form shown in Figs. 6 to 8 inclusive is dependent entirely upon the opening and closing of an electric circuit for a solenoid to effect actuation of the pilot valve per se while the form shown in Figs. 11 to 13 can be operated manually in addition to being electrically operated. The form of pilot valve unit shown in Figs. 6 to 8 inclusive will first be described in detail. Fig. 6 shows a pilot valve body I I2 which is of hollow construction to provide the valve chamber I I 3. A valve plunger H4 is positioned in this chamber and has the spring II5 bearing thereagainst to normally cause the plunger to engage the seat I I 6. This seating engagement closes oil the passage I I1 which functions to vent the pilot valve chamber H3 to the atmosphere. A second valve seat H8 is provided at the opposite end of the chamber H3. This second valve seat surrounds the passag H9 through the coupling nut I2 0 that is threaded in one end of the pilot valve casing and functions to connect the end of the tube H to the pivot valve casing. The tube 22 communicates with the pilot valve casing chamber II3 through the tapped opening I 2|. A plunger stem I22 extends from the pilot valve casing and is intended to be operated by suitable mechanism so that when this mechanism is actuated, the valve plunger II4 will be moved from th position illustrated in Fig. 6, where it engages the seat Hi, to a position where it will engage the seat H8. The position of the plunger II4 illustrated in Fig. 6 is such that the tubes 2I and 22 will be placed in communication with each other. When the plunger I is moved into engagement with the seat H0, the tube 2| will be closed and the tube 22 will be vented to the atmosphere through the passage 1.

Figs. 7 and 8 disclose in detail the electric operating mechanism for the pilot valve II 2. This mechanism includes a mounting plate I 23 v.asnsaaeo 7 to which the pilot valve H2 is suitably connected. A solenoid I24 also is connected to this mounting plate. This solenoid includes a suitable casing I25 in which is mounted the electric coil I28. An armature I21 is mounted in the bore of th coil and is provided with an operating rod I28 that passes through the mounting plate I23. The outer end of this operating rod loosely passes through one end of a valve operating lever I29. A shock absorbing spring I30 is interposed between the outer face of the lever I29 and an a'djustable nut I3I which is'threaded on the end of the rod I28. The remaining end of the lever is fulcrumed on a mounting pin I32 so that the lever will pivot when the solenoid armature I21 moves inwardly and outwardly relative to its coil I28. Fig. '1 clearly illustrates the lever as overlying and engaging the outer end of the plunger rod I22. It will be apparent, therefore, that when the solenoid coil I28 is energized to cause the armature I21 to move inwardly, the valve operating lever I29 will be pivoted relative to its fulcrum pin I32 and this pivotal movement of the lever I29 will cause the pilot valve plunger operating rod I22 to move inwardly. This inward movement of the plunger rod will continue until the plunger body H4 is moved into engagement with the seat II8, see Fig. 6. If this engagement of the plunger II4 with its seat H8 occurs before the solenoid armature I21 reaches its inner limit of movement, th spring connection I30 between the armature rod I20 and the lever I29 will permit the armature to continue its movement without damaging the pilot valve plunger II4.

The form of pilot valve unit shown in Figs. 11 to 13 includes the same pilot valve II2 withits tubes 2I and 22, its vent port or passage H1, and the pilot valve plunger operating rod I22. This pilot valve is connected to a mounting plate I32. This mounting plate also has secured thereto an electric solenoid I33 that has an armature operated rod I34 projecting through the mounting plate I32. This rod isbifurcated at its lower end I34a to allow for the passage of one end of the valve operating lever I35 which is pivotally mounted at its other end-by the pin I38 that is carried by the mounting block I31. A shock absorbing spring I38 encircles the outer end portion of the armature operated rod I34 and engages a stop pin I39. This spring engages the valve operating lever I35 in the manner clearly illustrated in Figs. 11 and 12. The lever I35 is provided with an adjustable screw. I40 which has its head arranged to engage the outer end of the pilot valve plunger operating rod I22.

The mechanism so far described functions in the same manner as the mechanism specifically plate I51.

described in connection with Figs. 7 and 8. The

unit of Figs. 11 to 13 inclusive, however, has added thereto a crank shaft I4I that is mounted for angular movement in the arms of the U- shaped bracket I42. This crank shaft MI is adapted to be operated by the hand wheel I43. The inner end of this shaft has a crank or throw I44 that passes through the hooked end I45 of the rod I48. This rod passes through the mounting plate I32 and the lever I35. A shock absorbing spring I41 is mounted on the end of the rod I48 and is held in place by th adjustable nut I48.

It will be appreciated that angular movement of the crank shaft MI in either direction will cause the rod I48 to be pulled upwardly for rocking thelever I35 in the same manner as the lever is actuated by the solenoid armature rod I34. This pilot valve unit I20 of Figs. 11 to 18 inclusive, therefore, can be automatically operated by the solenoid I33 or manually operated by 5:16 hand wheel 3' and its associated elemen s.

The selector valves 28, shown in Fig. 1, are

of identical construction and one of them is shown in detail in Fig. 9. The construction of this selector valve is very similar to the construction of the master. control valve shown in Fig. 6. The selector valve, however, differs in one important way from the construction of the master valve.

It will be appreciated that the master control valve normally is closed and prevents the. application of fluid pressure to the selector valves. However, when the master control valve is opened a sudden surge or rush of fluid pressure will be applied to the inlet side of each selector valve. As this sudden rush of pressure can build up more quickly in the inlet pressure chamber I48 of the selector valve casing I50 than it can in the power cylinder I5I, due to the restricted ilow path provided by the tubes 2I and 22 and the pilot valve II2, the lower face of the power piston I52 will be subjected to a higher pressure than th upper face of this piston and the selector valve would be caused to open either prematurely or unintentionally. The selector valves, therefore, must be constructed so that this sudden surge or rush of fluid will not cause them to be opened.

The selector valve casing I50 is flanged at its inlet end I53 and at its outlet end I54 for connection with the sections of the branch line 21. The outlet for the pressure chamber I49 is provided with a seat I55. This seat cooperates with the valve disc and carrier structure which are identical with the elements disclosed and described in connection with the master control valve of Fig. 6. Therefore, the same reference characters will be applied to these elements.

The valve casing I50 is provided with a top opening I58 that is partially closed by the barrier This plate is formed with a central opening I58 and a suitable packing structure I59 is provided to prevent leakage between this barrier plate I51 and the valve casing. A seating ring I is recessed in the upper surface of the barrier plate I51. concentrically with the opening I58 and so as to be exposed at the lower end of the power cylinder I5 I This power cylinder is formed by a section of steel tubing I8I. The opposite ends of this cylinder tubing are seated in packed recesses I82 and I83 formed respectively in the upper surface of the barrier plate I51 and the inner surface of the flanged cover plate I84. The barrier plate I51, power cylinder tube I8I and cover plate I84 are maintained in proper assembled relation by the bolts I85.

The cover plate is recessed or pocketed at I88 to accommodate the upper end. portion of the power piston loading spring I81. This pocketed portion of the cover plate is provided with a tapped opening I88 to receive the coupling I89 which is employed for connecting the tube 22 that leads from the pilot valve II2, not shown in this figure.

The power piston I52 is provided with a bifur-' end portion. of the loading spring I81. This power piston is provided with a top flange I12 that is peripherally tapered or beveled at I13 to allow for tilting movement of the piston when it reciprocates through the power cylinder I6I. A packing cup-leather I14 is provided for the power piston I 52 and a series of reinforcing spring steel strips I15 is provided for the cup-leather in the same manner as the power piston of the master control valve. A retainingring I16 is provided to clamp the cup-leather I14 and the spring strips I15 against the lower face of the flange I12.

This-power piston is provided with an annular seating rib or projection I11 which'is intended to seat against the ring I60 when the power piston is in its lowermost position, or the position it assumes when the valve disc 95 is closed. A relatively small bleeder port or opening I18 is formed in the power piston I52 to provide a restricted flow path or point of communication between the inlet chamber I49 of the valve casing and the annular space that surrounds the body of the power piston and is defined at its opposite ends by the barrier plate I51 and the piston flange I12 with its packing assembly.

The mode of operation of this valve now will be described.

With no fluid pressure within the inlet chamber I49 of the valve casing I and the power cylinder I5I, the spring I61 will retain the valve disc 95 in its seated position. The power piston I52 also will have its seating ring or projection I11 in engagement with the seating washer I carried by the barrier plate. When this valve structure is subjected to a sudden surge or rush of fluid, the fluid flows into the inlet chamber I49 and is quickly applied to the inner or rear surface of the valve disc 95 and the portion of the lower surface of the power piston which is surrounded by the annular seating ring or projection I11. Fluid pressure also builds up in the power cylinder I 5| as a result of flow of the fluid through the tubing 2| and 22 and thegpilot valve IZI. The small bleeder port or opening I18 formed in the power piston I52 also permits fluid pressure to build up in the annular space that surrounds the periphery of the power cylinder. This building up of fluid pressure in the annular space, however, is at a slower rate than the rate of development of fluid pressure within the power cylinder I5I. Therefore, a superior fluid pressure will first be created within the power cylinder I5I. This fluid pressure applied to the upper surface of the power piston will first exceed the total value of the fluid pressure applied to the lower surface of the power piston and these opposed fluid pressures will become equal when the pressure developed in the annular space surrounding the power piston equals the pressure developed in the power cylinder I5 I. The sudden surge or build up of fluid pressure within the valve casing inlet chamber I49, therefore, will not cause the valve disc 95 to be opened. This selector valve will only be opened in its normal intended manner; i. e., by venting of the power cylinder I5I by means of the pilot valve I I2.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

. l. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping excarbon dioxide at the hazard served thereby, said master valve including a seating member, and means for applying a yieldable load to said member to hold it against its seat so that a rise in vapor pressure of liquid carbon dioxide, trapped in the piping downstream of the master valve, to a value sufilcient to overcome the load applied to the seating member will effect unseating of said member to cause trapped liquid carbon dioxide to be returned to the source of supply.

2. A flre extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including ,a branch line for each hazard and a header common toall of the branch lines, a master valve adjacent the source of supply for the source of supply to prevent flow of carbon dioxide from said source when closed, and a setnereby, said shut-01f valve including a seating member, and means for applying a yieldable load o said member to hold it against its seat so that a rise in vapor pressure of liquid carbon dioxide,

trapped in the piping downstream of the shut-oil valve, to a value suflicient to overpower the load applied to the seating member will effect unseating of said member to cause trapped liquid carbon dioxide to be returned to the source of supply.

3. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines and draining toward said source of supply, a master valve adjacent the source of supply for controlsupply.

4. A flre extinguishingsystem for protecting one or more separate hazards, comprising a source or supply or liquid carbon dioxide,.piping extending from said source or supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in-each branch line for controlling discharge of carbon dioxide to thehazard served thereby, said master valve including a seating member closing in the direction of flow of the carbon dioxide through the valve, and means for applying a yieldable load to said member to hold it against its seat-so that a rise in the vapor pressure of liquid carbon dioxide, trapped in the piping downstream of the master valve, to a value sufiicient to overpower the load applied to the seating member will effect unseatin of said member to cause trapped liquid carbon dioxide to be returned to the source of supply. v

5. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the iiow of carbon dioxide through the header to the branch lines, a selector valve in each branch line for controlling the discharge of carbon dioxide at the hazard served thereby,

and an electric control system operating in response to the detection of a fire at a hazard for eilecting opening and closing of the master valve and the selector valve for the involved hazard, said master valve including a. seating member, and means for applying a yieldable load to said member to hold it against its seat so that a rise in the vapor pressure of liquid carbon dioxide, trapped in the piping downstream of the master valve, to a value suflicient to overpower the load applied to the seating member will effect unseating of said member to cause trapped liquid carbon dioxide to be returned to the source of supply.

6. A fire extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for maintaining the liquid carbon dioxide at a constant low temperature and its corresponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the tank for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master valve including a seating member, and means for applying a yieldable load to said member to hold it against its seat so that a rise in the vapor pressure of liquid carbon dioxide, trapped in the piping downstream of the master valve, to a value suiilcient to overpower the load applied to the seating member will efiect unseating oi said member to cause trapped liquid carbon dioxide to be returned to thetank.

7. A fire extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for maintaining the liquid carbon dioxide sponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines and draining toward said tank, a master valve adjacent the tank for controlling the ilow of carbon dioxide through the headerto the branch lines, a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master valve including a seating member, and means for applying a yieldable load to said member to hold it against its seat so that a rise in the vapor pressure of liquid carbon dioxide,

at a constant low temperature and its corretrapped in the piping downstream of the master valve, to a value suflicient to overpower the load applied to the seating member will eflect unseating of said member to cause trapped liquid carbon dioxide to be returned to the tank; and a vapor operated signal device connected to a high portion of the header and operable to indicate ,the presence of carbon dioxide trapped in the header and to slowly bleed vapor from the header. 8. A fire extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for maintaining the liquid carbon dioxide at a constant low temperature and its corresponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the tank for controlling the flow of carbon dioxide through the header to the branch lines, a selector valve in each branch line for controlling dis-- charge of carbon dioxide at the hazard served thereby, and an electric control system operating in response to the detection of a fire at a hazard for effecting opening and closing of the master valve and the selector valve for the involved hazard, said master valve including a seating member, and means for applying a yieldable load to said member to hold it against its seat so that a rise in the vapor pressure of liquid carbon dioxide, trapped in the piping downstream of the master valve, to a value sufilcient to overpower the load applied to the seating member will effect unseating of said member to cause trapped liquid carbon dioxide to be returned to the tank. 9. A fire extinguishing system. for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines and a selector valve in eacn branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving the power piston and in open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in said inlet, apilot line connecting the outer end of the power cylinder with the piping upstream of the valve, and a pilot valve in the pilot line having means for normally eflectlng flow oi fluid into the outer end of the power cylinder to cause the valve disc to be seated but being operable to effect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated.

10. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to beprotected and including a branch line for each hazard and a header common to all of 'the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving the power piston and inopen communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in said inlet, and controllable means for selectively creating equalized or differential fluid pressures in the inlet of the valve and in the power cylinder outwardly of the power piston to cause the valve disc to be seated or unseated respectively.

11. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving the power piston and in open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in said inlet, a pilot line connecting the outer end of the power cylinder with the piping upstream of the valve, a pilot valve in the pilot line having means for normally effecting flow of fluid into the outer end of the power cylinder to cause the valve disc 'to be seated but being operable to efiect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated, and an electric control system operating in response to the detection of fire at a hazard for efl'ecting actuation of the pilot valves of the master valve and the selector valve of the involved hazard to cause carbon dioxide to be delivered to the hazard to extinguish the tire.

12. A fire extinguishing system for protecting one or more separate hazards, comprising a source of supply 01' liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all 01 the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve carbon dioxide at the hazard served thereby. said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve same between its open and power cylinder receiving the open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fiuid pressure developed in said inlet, controllable means for selectively creating equalized or differential fluid pressures in the inlet of the valve and in the power cylinder outwardly of the power piston to cause the valve to be seated or unseated respectively, and an electric control system operating in response to the detection of fire at a hazard for effecting actuation of the controllable means of the master valve and the selector valve 01' the involved hazard to cause their valve discs to be unseated to cause carbon dioxide to be discharged to effect extinguishment of the fire and then to cause their valve discs to be reseated,

13. A flre extinguishing system for protecting one or more separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and for each closed positions, a power piston and in ing the same between its open and closed posiin each branch line for controlling discharge of tions, a power cylinder receiving the power piston and in open communication at its inner end disc for moving the 1 hazard served power cylinder to cause the vvalve disc to be seated but being operable to effect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated.

15. A flre extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for maintaining the liquid carbon dioxide at a constant low temperature and its corre'-' sponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the tank for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving the power piston and in open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in said inlet, and controllable means for selectively creating equalized r differential fluid pressures in the inlet of the valve and in the power cylinder outwardly of the power piston to cause the valve disc to be seated or unseated respectively.

16. A fire extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for maintaining the liquid carbon dioxide at a constant low temperature and its corresponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the tank to the one or more separate hazards to be tank for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a. power cylinder receiving the power piston and in open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in-said inlet, a pilot line connecting the outer end of the power cylinder with the piping upstream of the valve, a pilot valve in the pilot linehaving means for normally eifecting flow of fluid into the outer end of the power cylinder tovcause the valve disc to be seated but being operable to effect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated, and an electric control system operating in response to the detection of fire at a hazard for effecting actuation of the pilot valves of the master valve and the selector valve of the involved hazard to cause carbon dioxide to be delivered to the hazard to extinguish the fire.

1'7. A flre extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for-liquid carbon dioxide, means for maintaining the liquid carbon dioxide at a constant low temperature and its correspondjng low vapor pressure, piping extending from said protected and including a branch line for each hazard and a header common to all or the branch lines, a master valve adjacent the tank for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each includin a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving thepower piston and in open communication at its inner end with the inlet of the valve so as to subject one face or the power piston to the fluid pressure developed in said inlet, controllable means for selectively creating equalized or differential fluid pressures in the inlet of the valve and in the power cylinder outwardly of the power piston to cause the valve disc to be seated or unseated respectively, and an electric control system operating in response to the detection of flre at a hazard ,for effecting actuation of the controllable means of the master valve and the selector valve of the involved hazard to cause their valvediscs to be unseated to cause carbon dioxide to be discharged to effect e'xtinguishment of the fire and then to cause their valve discs to be reseated.

18. A flre extinguishing system for protecting one or more separate hazards, comprising an insulated storage tank for liquid carbon dioxide, means for-maintaining the liquid carbon dioxide at a constant low temperature and its corresponding low vapor pressure, piping extending from said tank to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the tank for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seatin valve disc, a fluid operated power piston connected to the valve disc for moving the samebetween its open and closed positions, a power cylinder receiving the power piston and in open communication at its inner end with the inlet of the valve so as to subject one face of the power piston to the fluid pressure developed in said inlet, and manually operable control mean for selectively creating equalized or differential fluid pressures in the inlet of the valve and in the power cylinder outwardly of the power piston to cause the valve disc to be seated or unseated respectively.

19. A flre extinguishing system for protecting one or more separate hazards, comprising a source of supplyof liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the flow of carbondioxide through the header to the branch lines and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, and a power cylinder receiving the power piston and opening at its inner end into the inletof' the valve so as to subject the inner face or the power piston to the fluid pressure developed in said inlet, a pilot line connecting the outer end oi the power cylinder with the piping upstream of the valve, and a pilot valve in the pilot line having means for normally .eitecting flow of fluid into the outer end of the power cylinder to cause the valve disc to be seated but being operable to effect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated, said selector valves each having means operatively associated with the inner end of their power cylinder and their power piston for causing the fluid pressure developed in the inlet of the valve to be applied to a portion of the inner face of the power piston at a slower rate than fluid pressure is developed in the outer end of the power cylinder through the pilot line and applied to the outer face of the power piston so that the rush of fluid created by the unseating of the valve disc of the master valve will not cause false operation of the selector valves.

20. A fire extinguishing system for protecting one or more. separate hazards, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to the one or more separate hazards to be protected and including a branch line for each hazard and a header common to all of the branch lines, a master valve adjacent the source of supply for controlling the flow of carbon dioxide through the header to the branch lines, and a selector valve in each branch line for controlling discharge of carbon dioxide at the hazard served thereby, said master and selector valves each including a seating valve disc, a fluid operated power piston connected to the valve disc for moving the same between its open and closed positions, a power cylinder receiving the power piston and opening at its inner end into the inlet of the valve so as to subject the inner face of the power piston to the fluid pressure prevailing in said inlet, a pilot line connecting the outer end of the power cylinder with the piping upstream of the valve, a pilot valve in the pilot line having means for normally effecting fiow of fluid into the outer end of the power cylinder to cause the valve disc to be seated but being operable to effect venting of the outer end of the power cylinder to the atmosphere to cause the valve disc to be unseated, said selector valves each having means operatively associated with the inner end of their power cylinder and the power piston for causing the fiuid pressure developed in the inlet of the valve to be applied to a portion of the inner face of the power piston at a slower rate than fluid pressure is developed in the outer end of the power cylinder through the pilot line and applied to the outer face ofthe power piston so that the rush of fluid created by the unseating of the valve disc of the master valve will not cause false operation of the selector valves, and an electric control system operating in response to the detection of fire at a hazard for effecting actuation of the pilot valves or the master valve and the selector valve oi the involved hazard to cause carbon dioxide to be delivered to the hazard to extinguish the fire.

21. A fire extinguishing system, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to a hazard to be protected, a valve in the piping adjacent the source of supply to normally exclude carbon dioxide from the piping downstream of the valve, a second valve in the piping between the first valve andthe hazard, means for causing both of said valves to open to effect flow of carbon dioxide from the source of supply to the hazard and for causing both of the valves to close to stop said flow, the closing of both of said valves causing liquid carbon dioxide to be trapped in the piping between the valves, and means for venting carbon dioxide vapor from the portion oi the piping between the valves.

22. A fire extinguishing system, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to a hazard to be protected, a valve in the piping adjacent the source of supply to normally exclude carbon dioxide from the piping downstream of the valve, a second valve in the piping between the first valve and the hazard, and means for causing both of said valves to open to effect flow of carbon dioxide from the source of supply to the hazard and for causing both of the valves to close to stop said flow, the closing of both of said valves causing liquid carbon dioxide to be trapped in the piping between the valves, the first mentioned valve having means for efiecting the return of trapped liquid carbon dioxide to the source of supply when the vapor pressur of the trapped liquid reaches a predetermined value.

23. A fire extinguishing system, comprising a source of supply of liquid carbon dioxide, piping extending from said source of supply to a hazard to be protected, a first valve in the piping adiacent the source of supply to normally exclude carbon dioxide from the piping downstream of the valve, means for opening and closing the first valve, a second valve in the piping between the first valve and the hazard, a piston and cylinder assembly operated by carbon dioxide pressure obtained from the portion 01' the piping located between the valves for opening and closing the second valve, means for creating equalized carbon dioxide pressures in the cylinder on opposit sides of its piston to hold the second valve closed and for creating differential carbon dioxide pressures on opposite sides of the piston in the cylinder to open the second valve, and means associated with the piston and cylinder assembly to prevent a sudden rush of carbon dioxide, caused by the opening of the first valve, from creating on opposite sides of the piston in the cylinder a difierential carbon dioxide pressure condition that will efi'ect false opening of the second valve.

CHARLES A. GE'IZ;

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