US2096383A - Automatic fire extinguishing system - Google Patents

Description

Oct. 19, 1937. i J, SEAT I 2,096,383

AUTOMATIC FIRE EXTINGUISHING SYSTEM Filed Dec. 30, 1935 Patented Oct. 19, 1937 PATENT OFFlCE 2,096,383 AUTOMATIC FIRE EXTINGUISHING SYSTEM Jay Lawrence Seat, Fairfield, Conn., assignor to Mergenthaler Linotype Company, a. corporation of New York Application December 30, 1935, Serial No. 56,748

14 Claims.

This invention relates to new and useful improvements in fire extinguishing systems and has particular reference to an automatic chemical spray system adapted to be installed in buildings and the like to. protect the same from serious damage by fire.

In accordance with the invention, there is provided a supply tank wherein the chemical fire extinguishing fiuid is stored, an air compressor for maintaining a suitable pressure head in the tank and a pipe line leading from the storage tank to a plurality of sprinkler heads arranged at strategic points about the building to be protected.

This application isa continuation in part of my copending application, Serial No. 621,223, filed July 7th, 1932, which has matured into Patent 7 2,025,782, and the sprinkler heads disclosed and claimed in that application are of the type preferably used in the system herein disclosed. As shown in the application referred to, the sprinkler heads are normally maintained closed by fusible links adapted, upon a temperature rise such as that experienced in the vicinity of a fire, to melt, thus allowing the sprinkler heads to open to efiect the discharge of the fire extinguishing fluid. Also, in accordance with the invention, the opening of the sprinkler heads or any of them will effect the closing of an electrical circuit through a motor which operates the compressor, so that at any time during the operation of the system, a sufficient pressure head will be maintained in the storage tank properly to eifect the discharge of fluid. In addition, a supplementary electric circuit is provided for operating the mo- 35 tor and which is controlled ,by a pressure operated switch responsive tothe pressure in the storage tank. -Thepressure switch is so constructed as 'to maintain the pressure in the system between predetermined lower and upper limits, i. e., should the pressure in the system drop as a result of partial usage of the liquid or leakage in the system, the pressure operated switch will cut in the motor when the pressure has dropped to a predetermined lower limit and will automatie cally operate to cut out the motor when the pressure has again been built up to a predetermined upper limit.

The system is essentially what is known as a dry pipe system, i. e., there is no liquid in the pipes or headers with which the sprinkler heads are associated whenthe system is in its normal inoperative condition, a pressure head of air being maintained in such pipes substantially equal to that in the storage tank. However, upon the opening of a sprinkler head, the accompanying drop in pressure in the pipe system will allow the fluid to be forced from the tank to the sprinkler heads for discharge therefrom.

It is apparent that, should leaks develop in a system of this character, the advantages thereof will be lost, since it is obvious that the reduction in pressure in the pipe system will allow the liquid to pass from the tank to the sprinkler heads even without any of the latter being opened. In order to prevent this and maintain the system dry at all times, there is provided, in accordance with the invention, a bypass connected between the storage tank and a point in the riser leading from the storage tank to the distributing pipes, at a level above that of the liquid in the tank. In the bypass there is located a'valve normally biased to an open position and which permits the pressure in the storage tank and pipe system proper to be maintained the same. However, upon the opening of a sprinkler head, resulting as it does in a substantial drop of pressure in the system, a large pressure differential will be created between the storage tank and the pipe system sufficient to effect the closing of the valve. When the valve has closed, the only communication between the storage tank and the sprinkler heads will be through the liquid pipe lines, and consequently the liquid will be forced from the storage tank to the sprinkler heads for discharge therefrom.

Referring to the drawing:

Fig. 1 is a front elevation, partly diagrammatic, and illustrating a system involving the present invention;

Fig. 2 is a detail view, partly in section, showing the bypass between the storage tank and the header leading to the pipe system; and

Fig. 3 is a schematic circuit diagram of the pressure operated switch for cutting the compressor in and out between the lower and upper pressure limits.

As shown in Fig. 1, the fire extinguishing system includes a storage tank 5 mounted on any suitable support 6 and partially filled with a chemical fire extinguishing fiuid 1, as for example, carbon tetrachloride. Above the liquid in the tank, there is reserved a space 8 wherein a suitable head of air may be built up. Connected with the space 8 above the liquid is an air compressor 9 which for convenience may be mounted on a stand 10 located on the tank and connected through the medium of a pipe I I with the air space 8 just alluded to. a

The compressor 9 is driven at the proper time by an electric motor 12 acting through an endless belt or other power transmitting means [3. The liquid 1 is preferably maintained under a pressure head of not less than thirty pounds per" square inch, and to this end means are provided whereby, when the pressure within the tank drops below a predetermined minimum, the motor I2 is automatically started to operate the compressor and build up thepressure within the tank-to. the desired head. A power supply line is indicated at 14 and has connected with it a line leading to a suitable pressure switch IS in communication with the interior of the tank 5 through a pipe IT.

'By way of illustration, the pressure switch IE.

(see Fig. 3) may include'a Bourdon tube it communicating with the tank 5' through. thepipe H and having an electrical, connection with the power line I5. Normally the switch It is, open,

but when the pressure in the tank falls belowthe predetermined minimum, the Bourdon tube Iii will coil up until it touchesthe contact it which is connected -by the lead l8 -with one ofthe wires:

I9'leading to the motor I2. A return lead Ill between the otherwire l9 and the line lfiicompl'etesthecircuitthroughthe motor todrive the compresson -When' the pressure in the tank 5 again reaches th'e desired head, the Bourdon tube I6 uncoils, breaking thecircuit, and stopping the motor, The power line laisalso connected with the [9 through a normallyopened grounded onthe system, theleads 35, 36; and switches on the sprinkler heads later tober deswitch 2s f One element o fi'the switch is the 9.1

matureofi a. relaywhichis connected to the power leadsld throughthe lead 20', the lead33,

scribed. I he switch- 29 connectingthe leads M with the motor: 1-2;;is normally'opened, but when any of the s'prinklerheads are rendered operative,

the :relay zll isenergized to close the switch 20 to completethe circuit through the motor.

Apipe-Z I- is in communication with the lower portion ofrtheinterior of the tank 5' and connected with this pipe 2| is an upright pipe or riser 22 from which extend: suitable laterals .or branches 23;. the'numberfiof which will-vary according :to' the structure to; be equipped with the apparatus; At suitable. intervalsalong the pipes 23; there arel'providedxsprinkler heads: 24, pre-ll-- erablyofl'the:character disclosed inzmy. copending application. previously referred to, andwhich, it

' is thought;.need not. be. described in detail. here.

Suffice it to say, however, a sprinkler headsof. the kindsreferred to; (includes a. body. portion: having a. recessed. chamber communicating. with: a. pipe 23 and closed at one end by a plunger valvear: ranged toacontrol-theiopening and closing "of ports communicating-1 witlr.the chamber and through which the'liquidzistdis'charged'. 'The valveLisheld.

iniitsportrclosingipnsition' against: the action of arcompressionspringi by. a fusible'link, which, in the: event alfire: occurs, will meltand allow the valve to be moved to port opening position under the'influenceioftheair pressure in the system and the influence; of: the spring with which-the sprinklerrhead isequippedz Upon theaopening of any of thesprinkler heads,

aacircuitzwillt be completed: through the relay 2%];

therebweffecting the closing. of. the switch 20 which. in turn completes the circuitbetween the up lyli'ne: Mi andithe; line le through the motor 12 whereby themotor willzbe energized to drive thelcompressor, allias previously described. From this itlwill beseen that, should the. temperature increase in the vicinity of but one sprinkler head that sprinkler head will open and the motor will be started to drive the compressor .30 maintain V and 38.

the pressure on the fluid in the tank. The pressure on the fluid in the tank will cause its passage .motor, so that when the switch 26* is closed upon the operation of the sprinkler. head, a signal will be given. The signal, of co-urse,maybe located at. any desired point. In order to facilitate testing, the system, a switch ll may be provided for manually closing the circuit through'the leads 35 V A manually operable relief valve 42 is provided in the pipeline II which may be used to release the air pressure when starting the a a motor for test purposes. Also, a pressure gauge 53 isprovided in the pipe line H" in order that the pressure within the tank Emay be determined at any time; Thepi'pe line 22 is provided with a cutoff valve 44 in-order that communication between thetank 5 and the upri'ghtfl may be cut off when it is desired to drain the piping system asthrough thevalve 4'5; The chemical'fire extinguishing. fluid. may be supplied to the tank through an opening normally closed by. a; plug it. The 1 system herein described is a dry pipe system, wherein air is trapped in the pipes leading to t'he sprinkler head, and were it not for the means presently to. be described, the liquid 1, due to...the pressure in the tank, would rise in the pipe 22 and escape should. a leak in the system occur. Such means include the pipes 46, 49 and avv valve 48 together constituting a connection from the top of the tank 5 to'the riser 22-alta point abovethe normal level of 'theliquid in the tank. "The valve lfl ispositioned at an anglebf' approximately and has a flap 52 arranged to hang vertically therein. The valve isnormally opened, permitting communication between the tankand tlie-riser 22-,"and'it's bias is such that a] difference in 'pres sure of about ten pounds between the tank and the pipe system is required to 9 efiect its closing. If small leaks occur in. the pipe,-the valve will remain open so that the pressures in thetank and pipe system become equalized and prevent the rise of liquid in the pipe 22 above: the normal level'ofthe liquid inthe tank;

Upon the operation of a sprinkler head, however,

the pressure inthe pipe system immediately drops (in excess often pounds belowthetank pressure) closing the valve- 52" and shutting off'communie cationbetween the upper part ofthe tank and the riser 2'2, with the result that theliquid is forced up through the riser and discharged from. the open' sprinkler, head. Should more than one j sprinkler head open at the same time, or should the sprinkler heads'open successively; the operation will be the same. V

Fromihe foregoingdescription; it will be apparent that the chemical under pressure is imme diately available upon the opening of a sprinkler head. w This, of course, is due to the arrangement 1 whereby the motor I2 is started and stopped automatically 'on the pressure within the tank 5 drop-' ping below a predeterminedminimum and reaching a predetermined maximum, Further, it will be understood that immediately upon the opening of a sprinklerhead; the motor {2 is started inde- I pendently of-the switch l6, so'that the compressor'will be actuated to'build up or maintain thepre'ssureiwithin the tank, irrespective of whether the same is at or below a predetermined minimum. Furthermore, as the circuit through the sprinkler heads is closed under the influence not only of the pressure in the system but also through the action of the compression springs with which such sprinkler heads are equipped, it is evident that good'electrical contact will be made.

In the accompanying drawing, the invention has been shown merely by way of example and in pre-v claim is:

1. A fire extinguishing system of the sprinkler type comprising a sprinkler head normally inoperative butadapted when operated to permit the discharge of liquid therefrom, a source of fire extinguishing liquid, means for connecting the source of liquid with the sprinkler head, an electrically operated motor driven air pump for producing a pressure head on the liquid at the source so as to supply said liquid to the sprinkler head under pressure, an electric circuit connected to said motor and means acting independently of the pressure in the system and functioning upon the operation of said sprinkler head to close the circuit through themotor.

2. A fire extinguishing system of the sprinkler type comprising a sprinkler head normally in-' operative but adapted when .operated to permit the discharge of liquid therefrom, a supply tank for fire extinguishing liquid, means connecting the supply tank at a point below the level of the liquid therein with the sprinkler head, an electrically operated motor driven air pump for producing a pressure head on the liquid in the tank so as tosupply said liquid to'the sprinkler head under pressure, an electric circuit connected to said. motor and means acting independently of the pressure in the system and functioning upon theoperation ofsaid sprinkler head to close the circuit through the" motor.

3. A fire extinguishing system of the automatically operated sprinkler type comprising a sprinkler head having fusible means normally maintaining it inoperative to discharge liquid, a source of fire extinguishing liquid, means connecting the source with the sprinkler head, an air pump for producing a pressure head on the liquid at the source so as to supply said liquid to the sprinkler head under pressure, means for driving said pump, a source of power for said driving means and means functioning automatically upon the operation of the sprinkler head and independently of the pressure in thesystem operatively to associate the source of power with the driving means to drive the pump.

4. A fire extinguishing system of the automatically operated sprinkler type comprising a sprinkler head having fusible means normally maintaining it inoperative to discharge liquid, a supply tank for fire extinguishing liquid, means connecting the supply tank at a point below the, level of the liquid therein with the sprinkler head, an air pump for producing a pressure head in the tank to supply liquid to the sprinkler head under pressure, means for driving said pump, a source of power for said driving means, and means functioning automatically upon the operation of the sprinkler head and independently of the pressure in the system operatively to associate the source of power with the driving means to drive the pump.

5. A fire extinguishing system of the sprinkler type comprising a sprinkler head normally inoperative but adapted when operated to permit the discharge of liquid therefrom, a supply tank for fire extinguishing liquid, a pipe connecting the tank at a point below the level of the liquid therein with the sprinkler head, an air pump associated withthetank for maintaining a pressure head in'the' system, an electric motor for driving the pump, means operated by the air pressure in the system and controlling the electric motor to maintain said pressure above a predetermined limit, and other means functioning when the sprinkler head is rendered operative also tocontrol the motor which drives the pump.

6. A fire extinguishing system of the sprinkler type comprising a sprinkler head normally inoperative but adapted when operated to permit the discharge of liquid therefrom, a supply tank for fire extinguishingliq'uid, a pipe connecting the tank at a point below the level of the liquid therein with the sprinkler head, a pump associated with the tank for maintaining pressure on the liquid in thesystem, an electric motor for driving the pump, means operated by the pressure in the system and controlling the electric motor to maintain said pressure. above a predetermined limit, and other means acting independently of the pressure in the system and functioning when the sprinkler head is rendered operative also to control the motor which drives the pump.

7. A fire extinguishing system of the sprinkler type comprising a sprinkler head having a valve and a fusible element associated therewith to normally maintain the valve inoperative to discharge liquid, a supply tank for fire extinguishing liquid, a pipe connecting the tank at a point below the level of the liquid therein with the sprinkler head, an electrically operated motor driven pressure pump associated with the tank, means operated by the pressure in the system and controlling the operation of the pump for maintaining the pressure on the liquid in the tank above a predetermined limit, a circuit including the motor, a pair of electric contacts in the circuit and arranged on the sprinkler head, and a spring associated with the sprinkler head, said spring being adapted upon fusing of the fusible element positively to open the valve and close the contacts whereby the pump is caused to function independently of the pressure control.

8. A fire extinguishing system of the sprinkler type, comprising a sprinkler head normally inoperative but adapted when operated to permit the discharge of liquid therefrom, a source of fire extinguishing liquid, a pipe connecting the source with the sprinkler head, an electrically operated motor driven air pump for producing a pressure head on the liquid at the source so as to supply said liquid to the sprinkler head under pressure, a circuit for the motor, and an electric switch actuated by the sprinkler head when the latter is rendered operative to close the circuit through the motor.

9. A fire extinguishing system of the sprinkler type, comprising a sprinkler head normally held inoperative by a fusible element, a source of fire extinguishing liquid, a pipe connecting the source with the sprinkler head, an electrically operated motor driven air pump for producing a pressure head on the liquid at the source so as to supply said liquid to the sprinkler head under pressure,

an electric circuit for the motor, aswitch: actufated. by the sprinkler head. when the latter. is.

rendered operative to close the circuit. through the motor,,and a. spring'for urging the head. to operativeposition. upon the 'fusingof the fusible element;

' 10. A fire. extinguishing system of the sprinkler type, comprising asprinkler headnormally-inoperative but adapted'when operated to permitthez discharge of liquidtherefroma supply, tank.- for fire extinguishingv liquid, a pipe connecting: the:

tank at a point below the. level of the liqulid;

therein. with the. sprinkler head, a compressor; communicating with the tank, an electric motor for drivingv the compressor, two control circuits.

for the motor; one-circuithaving a control switch operatedby the pressurein the tank to maintain the pressure on the liquid therein above a predetermined limit, and the other circuit having a switch operated by the opening of the sprinkler head. to start the compressor independently of the pressure in the tank.

11. In combination, a tank'for the storage of liquid, ariser pipe communicating with the tank substantially at the base thereof and. extending above the level of liquid in the tank, a'normally closed outlet for the pipe above the tank, a conduit between the tank. and the riser pipe above the normal li'quidlevel, means-for creating a pressure. head ofair in the tank and means associated with the conduit adapted to remain open duringsmall pressure drops-in theLpipeto' equalize the air pressure in the system, but adapted. to close during large pressure drops in the pipe as when the pipe outlet; is opened-to permit the discharge. of liquid therefrom.

12; A fire extinguishing system including, in

combination,. a tank. for the storage of liquid, means for maintaining a-substantial pressure head, of air in the tank, a riser pipecommunicating with the tank substantially at the base: thereof and with a dry pipe system including sprinklermeans arranged above the level of the liquid in-the tank, said sprinkler means being normally closed.

but'capable of being opened under fire conditions, a normally open connection between the top of the tank and the riser'pipe at a point above the a oaaasaz I levelof the. liquidjinthetankfor maintaining the,

combination, a tank for thestorage of liquid, means for maintaining a substantial pressure head of. air-in the tank, a riser pipe communicating with the tank substantially at-the base thereof and: with a dry pipe system including sprinkler means arranged above the level ofthe liquid in the tank,v said sprinklermeans being normally closed but capable of being opened under the conditions, anormally openv connection between the top of the tank and the riser pipe at a point A 7 above the levelof the liquid in the tank for maintaining the air pressure in thepipe-system substantially .equal to that in the tank, and means acting automatically and directly as a'result of the air pressurezdifference created upon the opening of the sprinkler means to close said connection' whereby the liquidzmay be, forced from the tank through the riser pipe to the open sprinkler means.

14..A. fire extinguishing system including; in combination, a tank for. the storage of liquid,

means for maintaining a substantial pressure head of air; in the1tank,;a riser pipe'comrnunicating with the tank substantially at the base thereof andwith a dry pipe system including sprinkler means arranged above the level of the. liquid in the, tank, said sprinkler means 'beingnormally closed but capable of being opened under fire con-- ditions, a connection between the top of the tank and the riser pipe at a point above the levelof the, V liquid in-the tank, and a valve in said connection normally biased to open condition to allow equalization ofthe air pressure in the tank and in the pipe system, said valve being adapted to close upon 7 the opening of the sprinkler meanswhereby the liquid may be forced from the tank through the f g riser pipe to theopen sprinkler means.

JAY LAWRENCE SEAT.

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