US2414260A - Fire-foam producing apparatus - Google Patents

Description

Jan. 14, 1947. J. HUNTER 2,414,260

- FIRE FOAM rnonuczne APPARATUS Filed Sept. 1, 19 14 2 Sheets-Sheetl Jan. 14, 1947. J. N. HUNTER 2,414,260

FIRE FOAM PRODUCING APPARATUS Filed Sept. 1, 1944 2 Sheets-Sheet 2 J 8 35' ATTORNEY hTATES 2,414,260 FIRE-FOAM PRODUCING APPARi tlTE S Application September 1, 1944, Serial No. 552,353

In Great Britain 6 Claims. (Cl. 261-77) Provision is sometimes made for extinguishing fires in oil storage tanks by forcing foam into the tank to rise through the oil and form a blanket on the surface. In order to reduce the pipes and fittings to a minimum it is convenient to make use of theexisting pipe lines for the supply of foam, and simply to provide a threaded connection onto which a foam-producing apparatus may be screwed as required. The foam-producing apparatus may advantageously be of the kind commonly known as a branchpipe, that is to say, an apparatus having one or more jet nozzles or orifices to which liquid is supplied under pressure and formed with one or more openings through which air is drawn by the jets of liquid, the liquid and entrained air passing together through a tubular part of the apparatus and becoming intimately mixed in the process. The liquid may be a solution of a foam-stabilising compound in water 01 may simply be water, the foam-stabilising compound being drawn in by the jet or jets in addition to the air. In either case the eflect is to produce foam mechanically and the product is known as air foam.

Now in many oil storage plants a single pipe is used tor both the delivery of oil to and with- 'lrawal of oil from the tank, so that all the valves in the pipe must be manually actuated and they are generally of the screw-downtype. In consequence, ii the pressure of liquid through the August 23, 19413 Fig. 3 shows part of the hranchpipe in longitudinal section and is on a larger scale;

Figure 4 is a section on the line IV-l[V in Figure 3;

Figure 5 is a section through a branchpipe having a modified form of nonreturn valve;

Figure 6 shows yet another hranchpipe, similar to that shown in Figure. h but provided with manual means for operating non-return valve;

Figure 'l is a section on the line VII-Jill in Figure 6; and

Figure 8 is a detail View in perspective lllus trating a portion of the manual means for operating the check valve of Figure 6. 7

Referring first to Figures i to i, an oil tank l is shown with a pipe it through which oil is normally both supplied to and withdrawn from the tank. The flow in this pipe is controlled by a screw-down valve 3. A whtting l is let into the pipe, one arm of this being controlled by a screw-down valve 5 and being connected to the oil supply and withdrawal line it. The other arm of the Y-iitting terminates in an internally screw- 1 threaded connection l and includes a screw down valve 8.

In the event of tire breaking out in the tank a end It isjoined to the connection l and used branch pipe should fail or be cut on during the supply of foam the oil in the tank can run backwards and escape through the air inlet or inlets in the branchpipe, thus greatly increasing the are risk.

This disadvantage is overcome according to the present invention by providing an automatic nonreturn valve in the branchpipe itself. This valve may, for example, consist of a ball sliding in a cage in a flaring part of the branchpipe and arranged to close a throat in the pipe if the liquid pressure in the pipe should reverse in direction. Again, a clack valve may be provided in the forward part of the branchpipe.

Since any non-return valve may tend to stick in its open position, as a result for example of the deposition of sediment, provision may be made for operating it manually if necessary.

Some apparatus in accordance with the invention will now be described by way of example with relevance to the accompanying drawings,

which:

Figures l and 2 show diagrammatically, and in plan and elevation respectively, part of an oiltank installation with a branchpipe in position;

to form foam, which to ed into the tank l through the pipe ly the valve 3 must be closed while the branchpipe is being fitted in position and the valves ii and it must he open to allow the foam to pass to the tank i.

, The branchpipe consists of a jet-producing head it to which solution loam-stabilising compound in water is supplied through a pipe coupling 11?, a conical part ill, in which con vergent jets delivered from the head it flew, a throat i l and a daring part it leading to a cylindrical part or receiver it which terminates in the screw-threaded part it. The head it is sur rounded by a conical hood it which is open to the atmosphere and through which air is drawn in by the jets of liquid.

The non-return valve that is provided accord ing to this invention takes the form of a ball it placed in a cage it which projects forward from the throat it. When learn is lacing produced this ball is forced away from the throat it by the foam. If the how in the hraochpipe tends to reverse the ball l; closes the throat.

Since the hall of the cage it manually if necessary.

form of a rod 20 projecting into the cage I! through a slot in the wall of. the latter and fixed to a rod 2 I which passe through the walls of the cylindrical part Hand of the flaring part it and l is journalled'in two glands 22 and 23 fitted in openings in these walls. The rod 2i is keyed to a crank 24, and a. rod 25 is pivoted at one end to the crank 24 and close to its other end passes through a guide 26 fixed to the branchpipe. The

rod 25 is provided with a handle 21 and when it is pulled rearwardly by graspingthis handle 21 the rod 2| i rocked about a horizontal axis in the glands 22 and 23 so that the rod 23 is rocked in a vertical plane and dislodges the ball I! from the end of the cage 19.

In the modification shown in Figure 5, the nonreturn valve is a clack valve 28 pivotally mounted at 29 in an oifset part 36 of the wall of the branchpipe and closing against an abutment 30 inside the branchpipe. This clack valve is most conmunication with the atmosphere, the discharge veniently placed at the end of the flaring part II as shown in Figure 5. I

In the modification shown in Figures 6 and 7 a clack valve 28 i again used and means are provided for operating it manually when desired. These means take the form of a cranked lever 32 keyed to a rod 33 to which the clack valve is actually fixed and which is carried in bearings 34 in the offset part 38 of the branchpipe. The lever 32 has a lost-motion connection with an operating rod 35 which runs along and outside the branchpipe; The lost-motion connection allowsthe clack valve to move'freely without the rod 35 being moved. g I

I claim:

i. In apparatus of the character described including a tank for a combustible liquid and a the discharge of liquid from said tank through said first mentioned means.

3. In apparatus of the character described including a tank for a combustible liquid and a main liquid delivery pipe communicating with said tank adjacent its bottom, thecombination of a branchpipe connected with said main pipe,

and an air-foamgenerator connected with said branchpipeand arranged to deliver fire extinguishing foam through said main pipe into the bottom of said tank, said foam generator com-' prising a receiver having means adjacent its inlet end serving t place said receiver in open comend of said receiver being connected with said branchpipe, means for delivering a foam-forming solution under pressure into the inlet end of the receiver in a manner to aspirate air through said first mentioned means, means providing a restricted throat within said receiver through which said foam forming solution and air are passed, and a check valve within said receiver cooperating with the discharge side of said throat for permitting the flow of said solution and air therethrough but preventing the reverse flow of said combustible liquid therethrough.

4. In apparatus of the character described including a tank for a combustible liquid and a main liquid delivery pipe communicating'with said tank adjacent its bottom, the combination of a branchpipe connected with said main pipe, and I an air-foam generator connected with said branchpipe and arranged to deliver fire extinguishin foam through said main pipe into the bottom of said tank, said foam generator comprising a receiver having means adjacent its inlet end serving to place said receiver in open communication with the atmosphere, the discharge end of said receiver being connected with said branchpipe, means for delivering a'foam-forming solution under pressure into the inlet end of receiver in a manner to aspirate air through said first mentioned means, and a check valve within said receiver arranged to prevent the discharge of liquid from said tank through said first mentioned means. i

2. In apparatus of the character described in-- cluding a tank for. a combustible liquid and a main liquid delivery pipe communicating with said tank adjacent its bottom, the combination of a branchpipe connected with said main pipe, a shut-oii valve in said branchpipe, andan airi'oam generator connected with said branchplpe 'at a point more remote from said tank than is said shut-on valve and arranged to deliver the extinguishing foam through said main pipe into the receiver in a manner to aspirate air through said first mentioned means, a check valve within said receiver arranged to prevent the discharge of liquid from said tank through said first mentioned means, and manually operable means for shifting said check valve into closed position.

5. In apparatus of the character described including a tank for a combustible liquid and a main liquid delivery pipe communicating with said tank adjacent its bottom, the combination of a branch pipe connected with said main pipe, and an airi'oam generator connected with said branchpipe and arranged to deliver fire extinguishing foam through said main pipe into the bottom of said tank, said foam generator comprising a, receiver 5 having means adjacent its inlet end serving to place said receiver in open communication with the atmosphere, the discharge end of said receiver being connected with said branchpipe, means for delivering a foam-forming solution under pressure into the inlet end of the receiver in a manner to aspirate air through said first mentioned means, and a check valve within said receiver the bottom of said tank, said foam generator comprising a. receiver having means adjacent its inlet end serving to place said receiver in open communication with the atmosphere,.the discharge end of said receiver being connected with said branchpipe, means for delivering a foamiorming solution under pressure into the inlet end of the receiver in a manner to aspirate air through said first mentioned means, and a check valve within said receiverarranged to prevent arranged to prevent the discharge of liquid from said tank through said first mentioned means, said check valve comprising a cage within said receiver and a ball shiftabie either into active or inactive position depending upon the direction 0!- flow of the liquid through said receiver.

6. In apparatus of the character described including a tank for a combustible liquid and a main liquid delivery pipe communicating with said tank adjacent its bottom, the combination of a branchpipe connected with said main pipe, and

an air-foam generator connected wit said branchpipe and arranged to deliver fire extin-s guishing roam throughsaid main pipe into the bottom of said tank, said foam generator comprising a receiver having means adjacent its inlet end serving to place said receiver in open communication with the atmosphere, the discharge end or said receiver being connected with said branchpipe, means for delivering a foam-torming solution under pressure into the inlet end or 10 the receiver in a manner to aspirate air through said first mentioned means, and a check valve within said receiver arranged to prevent the discharge or liquid from said tank through said first mentioned means. said check valve comprising a flap member arranged to permit the desired flow of said foam-forming solution, but to prevent the reverse flow of said combustible liquid through said receiver.

JOHN NORMAN HUNTER.

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