US2818121A - Fire-extinguisher - Google Patents

Description

Dec. 31, 1957 w. CLIFF-0RD ETA],- 2,818,121

FIRE-EXTINGUISHER Filed Feb. .6, 1956 5 Sheets-Shed 1 Dec. 31, 1957 w. J. CLIFFORD El'AL 2,818,121

FIRE-EXTINGUISHER 5 Sheets-Sheet 2 Filed Feb. 6, 1956 Dec. 31, 1957 w. J. CLIFFORD ETAL FIRE-EXTINGUISHER 5 Sheets-Sheet 5 Filed Feb. 6, 1956 V. ,1. n l I II I: rllll/ i I11 I lllllm t a Dec. 31, 1957 w. J. CLIFFORD ET AL 2,818,121

FIRE-EXTINGUISHER Filed Feb. 6, 1956 5 Sheets-Sheet 4 Dec. 31, 1957 w. J; CLIFFORD ETAL 2,818,121

FIRE-EXTINGUISHER Filed Feb. 6, 1956 5 Sheets-Sheet 5 nit FlRE-EXTINGUISHER Application February 6, 1956, Serial No. 563,776

Claims priority, application Great Britain February 10, 1955 8 Claims. c1. 169--9) This invention relates to fire-extinguishing apparatus of the kind in which a fire-extinguishing powder is expelled from a closed container through a discharge tube by introducing'a gas under pressure from a cylinder or the like, which may be separate from, within or mounted on the container. The gas under pressure is usually carbon dioxide, and the discharge tube is usually a hose.

It is important to ensure that the particles of powder are loosened and disturbed before any of the powder is driven out of the container, since otherwise compacted lumpsof powder may clog the discharge tube or any passages leading to it. It is convenient to disturb the powder by introducing at least some of the gas below the normal powder level while maintaining the container closed, and subsequently allowing the gas to expel the powder.

The principal object of this invention is to enable the necessary sequence of steps to take place automatically once the gas has been released from its cylinder.

Another object of this invention is to provide a fireextinguishing apparatus containing a dry extinguishing powder in which means are provided for initially disturbing the powder and thereafter for discharging the powder under continuously decreasing pressure.

A further object of the invention is to provide a novel set of interrelated valves for controlling the operation of a dry powder fire extinguisher.

In our invention a pressure-operated diverting valve set to deliver the gas into the space in the container in which the powder lies to disturb the powder is exposed to the pressure in the container to be actuated upon a predetermined rise in pressure in the container to divert the gas to two difierent points, namely a flow-controlling device through which the gas thereafter flows to the container and an isolating valve which is set to isolate the discharge tube from the interior of the container and which is actuated by the diverted gas to allow the powder to be driven out of the container to the discharge tube.

The flow-controlling device may serve to restrict the rate of flow into the container during the discharge of the powder to a value such that the pressure in the container falls continuously; or it may stop the flow completely on the pressure in the container reaching a predetermined value. Preferably it performs both these functions.

The reason why the flow-controlling device should ensure that the pressure in the container falls continuously is that if the pressure falls minute pockets of gas expand and break up any powder compacts, whereas if the pressure rises any such compacts are not broken up and cause the flow of powder to be uneven. Therefore the preferred device includes an orifice of a size so correlated with that of the discharge tube and any other passages through which the gas flows that the desired result is obtained.

The reason why the flow-controlling device should stop the flow completely on the pressure in the container reaching a predetermined value is that the pressure in the cylinder or the like is commonly so high, e. g. 800 lbs. per square inch, that it is undesirable to allow all the. gas to atent "ice enter the container at once, since the pressure init: would be initially too high for conveniently, discharging the powder at astable. rate. Now the actual discharge; of powder is usually controlled-by a. manual valve onthe discharge hose or other'discharge tube. If it is-nohopened immediately the diverting valve moves, or isclosedfor any length of time after once being opened, the pressure in. the container will build up. Thereforethe preferred flow-controlling device also includes a valvev actuated by a pressure-responsive deviceexposed to the pressure-i11- side the container and operative to stop the entry;of;gas into the container if a' predeterminedfpressureisreached in the container during operation.

In apparatus of the kind inquestion the. powder; is driven to the dischargetube'through an outlet tubeconnected to the interior of the container. Thistube, which is often a dip tube extending downwards from the top of the container, but may be a'tube leading from the bottom of the container, is liable to be clogged. Therefore we prefer to introduce the gas initially through the outlet tube to clear it. For this purposewe connect the cylinder or the like to a chamber in the isolating valvewhiclr is also connectedto the outlet tube.-

The preferred apparatus will now be describedin detail with reference tothe accompanying drawings, in which:

Figure 1 is a diagram showing the apparatus in outline and indicates the gas'flows duringthe disturbanceof the powder;

Figure 2 is a diagram similar to l-Figure 1 and indicates the gas flows duringdischarge;

Figure 3 is a diagrammatic showing: of the various valves in more detail and corresponds to Figure 1;

Figure 4 is similar to Figure 3 but corresponds to'Figure 2;

Figure 5 is a side elevation of the preferred embodiment of the invention;

Figure 6 is a planet this embodiment;

Figure 7 is an enlarged plan view of a valve-assembly in the preferrediembodiment;

Figure 8 is a section on the line V1IIVIII in Fig: ure7;

Figure 9 is a. section on the line IX-IX'in Figurefl; and

Figure 10 is a section. on the line XX in Figure 7;

The apparatus shown in Figures- 1 and 2 comprises acontainer 1 for dry fire-extinguishing powder which is tobe expelled through adip tube 3 to adischarge hose 4 by carbon dioxide released from acylinder 5 in which it is stored under high pressure. Three valves are mounted on the top of the container, namely a divert-ing valve 6-, an isolating valve. 7: and a flow-controllingdevice 8.

Thecylinder 5 is connected by a pipe 9' to the divertingvalve 6 and at the start of the operation flows through this valve to apipe 10 leading to achamber 11 in theisolating valve 7; The top of thedip tube 3 opens into this chamber, which is separated from anotherchamber 12 by awall 13; through whichapiston rod 14 passes. On one side of thewall 13 the rod 14- carries avalve member 15 and on the other side it' carries apiston 16 subjected to the action of acompression spring 17. Adischarge port 18 leading to a connection 19' for thehose 4 is controlled by thevalve member 15, being closed unless the piston is moved to the left as seen in the drawings against thespring 17. Thus: the gas entering thechamber 11 cannot pass tothe-hose 4', but is all delivered down thedip tube 3" to disturb the powder.

The pressure in thecontainer 1 builds up rapidly and on reaching: a predetermined value operates the divertingvalve 6. This valve includes a valve member which serves to connect thepipe 9 to thepipe 10 when in the position shown in Figure 1 but to shut off thepipe 10 when in the position shown in Figure 2 and instead to connect thepipe 9 to twofurther pipes 21 and 22. Thepipe 21 leads to thechamber 12, and the gas entering this chamber forces thepiston 16 to the left and so opens theport 18, with the result that discharge of powder begins. Thepipe 22 leads to theflowcontrolling device 8, so that the gas now enters thecontainer 1 at a lower rate.

It will be seen that the isolatingvalve 7 ensures that there is no loss of pressure by flow through the discharge outlet until the diverting valve is actuated to let gas flow through thepipe 21. The discharge of powder onto a fire is controlled by a manually-operated valve (not shown) close to a discharge nozzle on thehose 4, but this valve may be opened prematurely, whereas theisolating valve 7 will remain closed and prevent discharge until the divertingvalve 6 has been actuated. i The flow-controllingdevice 8 ensures that when the desired pressure has been built up in thecontainer 1 during the step of disturbing the powder, the gas entering to expel the powder through the opened isolatingvalve 7 flows at a rate such that the pressure in the container falls so long as the powder discharge proceeds normally. Thedevice 8 is a valve, made as described in our application Serial No. 563,789, filed February 6, 1956, so that it will close automatically if the pressure rises during discharge as a result of closure of a manually operated valve at the end of thehose 4 or of blockage of any of the parts through which the powder flows.

As shown in Figures 3 and 4 the flow-controllingdevice 8 comprises acasing 23 in which achamber 24 is formed, thepipe 22 leading into this chamber. The bottom of thechamber 24 is formed by awall 25 in which there is anorifice 26 leading to aflaring passage 27. The chamber is also bounded by awall 28 through which avalve stem 29 passes, this stern carrying avalve member 30 and having ahead 31. Aspring 32 surrounds the stem to urge the head upwards and therefore to maintain theorifice 26 open. Ahood 33 around part of thecasing 23 bounds apassage 34 leading from the interior of thecontainer 1 to abellows 35, the lower end of which is rigid with thehead 31. Thus, on the pressure in thecontainer 1 reaching a predetermined value, the bellows expands so much as to cause thevalve member 30 to close theorifice 26.

In designing the extinguisher, the time required for complete discharge of the contents and the pressure range in the container during discharge, say initially 150 lbs. per square inch falling to 80 lbs. per square inch, are first decided. The diameter of theoutlet tube 19 and discharge hose 4- are chosen to allow this rate of discharge to be obtained, and then the size of theorifice 26 is calculated to ensure that the gas will enter through it at a rate which makes the pressure in the container fall continuously.

The construction of the divertingvalve 6 is also shown in Figures 3 and 4. Thevalve member 20 has astem 36 which lies in acylindrical passage 37 in awall 38 and which carries twovalve discs 39 and 40. These serve to close the opposite ends of thepassage 37 and so direct the flow of gas to achamber 41 in Figure 3 and thence to thepipe 10 or to achamber 42 in Figure 4 and thence to thepipes 21 and 22. Thestem 36 passes downwards through agland 43 into abellows 44 which lies inside thecontainer 1. Aspring 45 around the stem expands the bellows so the normal position of thevalve member 20 is that shown in Figure 1. When the pressure in thecontainer 1 has risen to the predetermined value, it overcomes thespring 45, with the result that thestem 36 moves, carrying thevalve disc 39 0E its seat and thevalve disc 40 onto its seat,

4 and thus diverting the gas to the isolatingvalve 7. The two valve discs are preferably of equal effective areas.

To enable thehose 4 to be cleared it the fire is extinguished before the container has been completely discharged, a by-pass connection is provided between thecontainer 1 and the connectingpiece 19 as shown in Figures 1 and 2 and is controlled by a manually operated valve comprising avalve member 47 lying inside the con= tainer, astem 48 passing through the connectingpiece 19, ahead 49 and aspring 50 surrounding the stem beneath the head to maintain the valve closed. This valve can be opened also if the pressure in the container must be released at any time without expelling powder.

As one of various modifications which may be made, the gas for disturbing the powder in the container may be introduced through a tube terminating in the middle of the container, and then this gas need not pass through the isolating valve. Moreover in such a case the tube may be used as the means through which the gas is subsequently introduced into the container under the reduced pressure, a connection being provided between it and the outlet side of the reducing valve.

The apparatus shown in Figures 5 to 10 works on the principle illustrated by Figures 1 to 4, and the same reference numerals are used to identify the corresponding parts.

In this apparatus thecontainer 1 andcarbon dioxide cylinder 5 are mounted on a trolley withWheels 51 and ahandle 52. The container is charged with powder through an opening closed by acap 53. Thecylinder 5 has a squeeze-grip valve 54- by which the release of the gas into thepipe 9 is controlled. Thehose 4, which may be stored as a coil around thecontainer 1 as shown in Figures 5 and 6, terminates in adischarge nozzle 55 controlled by a valve.

The isolatingvalve 7 is best shown in Figure 8. Thewall 13 is made in one piece with acasing 56 housing thespring 17 and closed by an end cap 5'7 having anopening 58 to relieve the internal pressure. Thecasing 57 is screwed into ablock 59 which also forms the connectingpiece 19 and bounds thechamber 11.

The divertingvalve 6 is housed in thesame block 59.

We claim:

1. A fire-extinguishing apparatus comprising a container adapted to hold a fire-extinguishing powder and to permit the discharge of the powder by gas under pressure, said container comprising first and second gas inlets, said first inlet being located in the powder containing space in said container, valve means in said discharge tube, pressure-responsive means for actuating said valve to the open position, a source of gas under pressure, means including a pressure-operated diverting valve normally connecting said source to the first of said inlets, said diverting valve being responsive to the pressure in said container and operative upon a predetermined pressure being attained therein to divert the gas from said first inlet to both said second inlet and to the actuating means for said discharge valve means.

2. A fire-extinguishing apparatus according toclaim 1 and further comprising means including an orifice in the second inlet valve to continuously decrease the pressure in the container during discharge of the powder.

3. A fire-extinguishing apparatus according toclaim 2 and further comprising valve means in said second inlet, and means responsive to the internal pressure in the cylinder to actuate said valve means, said actuating means closing said valve means when the pressure in the container reaches a predetermined amount.

4. A fire-extinguishing apparatus according toclaim 3, wherein said valve means included a lift member directly closing the orifice.

5. A fire-extinguishing apparatus comprising a container adapted to hold a fire-extinguishing powder and to permit the discharge of the powder by gas under pressure, said container comprising first and second gas inlets,

said first inlet comprising a chamber into which gas is fed, and a tube leading from said chamber and extending into the powder containing space in said container, said tube further serving as the discharge tube, a discharge outlet leading from said chamber valve means in said discharge outlet, and pressure-responsive means for actuating said valve means to the open position, a source of gas under pressure, means including a pressure-operated diverting valve normally connecting said source to said chamber, said diverting valve being responsive to the pressure in said container and operative upon a predetermined pressure being attained therein to divert the gas from said first inlet to both said second inlet and to the actuating means for said discharge valve means.

6. Apparatus according toclaim 5 wherein said first in let comprises a first chamber into which gas is fed, a tube leading from said chamber and extending into the powder containing space in said container, said tube further serving to discharge the powder from said container, at discharge outlet leading from said chamber, valve means in said discharge outlet, a second chamber adjoining said first chamber, piston means in said second chamber, shaft means connecting said piston and valve means, and spring means tending to hold said valve means closed against the action of gas pressure on said piston.

7. An apparatus according toclaim 5 in which the diverting valve comprises a valve member carried by a stem which is moved against spring action by the pressureresponsive device that actuates the discharge valve.

8. An apparatus according toclaim 5 in which a bypass connection is provided between the container and the downstream side of the discharge valve and is controlled by a manually operated valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,347,358 Adams July 20, 1920 1,889,163 VogelJorgcnsen Nov. 29, 1932 2,681,115 Guise June 15, 1954

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