US2405652A - Fire extinguishing apparatus - Google Patents

Description

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' FIRE AEXTINGUISHING APPARATUS Filed oct. 12,' 1945 2 sheets-sheet 1 l l l l I l I l I I I l l .1

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FIRE EXTlNGUISHING APPARATUS 4 Filed oct. 12, 194; 2 sheets-sheet a as F9, 6 w59 .mtv

.Zhi/)er FlsHER 1 Bavo FRANcIs 1. HOGENMuLLER Laws w. Beaune@ Patented Aug. 13, 1946 UNH n sarge 2,405,652 Fins Exrmemsme APPARATUS Francis J. Hogenmiller, Philadelphia, Fisher L. Boyd, West Chester, and Lewis W; Boerner, Newtown Square, Pa., assgnors to National Foam System, Inc., Philadelphia, Pa., a corporation of Delaware Application October 12, 1943, Serial No. 505,900

12 Claims.

point therein where the stream is iinelysub-divided. or dispersed and where a suitable gas (usually air from atmosphere) is entrained in such manner as to cause a mingling of the liquid and gas as they move in the conduit towardthe point of discharge therefrom. Typical of this method of producing mechanical foam is that which is described in United States Letters Patent No. 2,106,043, granted January 18, 1938, and No. 2,198,585, granted April 23, 1940.

In order'to insure the production of foam of the desired uniform quality, it is necessary that the rate cf introduction of the foam-forming material into the flowing stream of water be proportional to the rate of flow of the water, while in order to insure an adequate projection of the foam from the discharge nozzle it is necessary to maintain a considerable head of pressure upon Vthe Water stream. Y

An apparatus for securing these objectives is disclosed in United States Letters Patent No. 2,327,335, granted August 24, 1943, to L. W. Boerner and F. J Hogenmiller, it being noted that by means of such apparatus there is insured not only the maintenance of a maximum head of pressure in the water stream to provide for adequate projection of the stabilized foam, but also the utilization of the full available head of pressure to inject the stabilizing material into the water stream at a'rate which is automatically proportioned to the rate of flow of the water stream. Also, such apparatus includes mea-ns for utilizing the full head pressure of the water stream to force the foam-forming material from its source of supply into the water stream without, however, effecting any substantial mixing of the Water` with the supply of foam-forming material.

More recently there has been devised a dual construction of apparatus operable in accordance with the principles disclosed in the said Boerner and Hogenmiller application, the primary purpose of which is to provide an arrangement for producing mechanical or air foam substantially continuously and uninterruptedly over an extended period, as may be required in the extinguishment of an extensive re requiring a large quantity of foam-forming material. In oneform of this dual' arrangement of pressure proportioner unit, a pair of vertically spaced reservoirs are provided for the foam-forming material from which the latter may be withdrawn for injection into the water stream, the foaming material be` ing delivered first from one reservoir and, then, upon exhaustion of that supply, from the other reservoir. In addition, the arrangement provides means for lling the exhausted reservoir with a further supply of foaming liquid during the Iperiod that the filled reservoir is in operation, the

two reservoirs being thus adapted to be alternately exhausted of and lled with the foamforming liquid to provide for continuous injection thereof into the iiowing stream of water and corresponding continuous production of reextinguishing foam. l

The present invention relates more particularly to the control means for effecting the selective and alternate operation of the dual mechanisms for continuously introducing the foaming liquid into the flowing stream of water and has as its primary object the provision of a valve means `which is designed to render the dual pressure proportioner unit operative for its intended purpose.

A further object of the present invention is to provide a control means for the dual unit aforesaid which includes a pair of commonly actuated valves operative respectively to divert a portion oi the water under pressure from its main conduit into one or theother of the dual reservoirs containing the foam-forming liquid to provide a suitable pressure head upon the liquid therein and to direct the liquid so subjected to pressure into the water stream, the control means being adapted to be set in one or the other of two extreme positions so that a portion of the water under pressure may be diverted from its main stream into one or the other of the two reservoirs to force the foaming liquid therefrom and into the main stream of the flowing water.

Still another object is to provide the control means with an atmospheric vent which is operative automatically as the valves are set to force foaming liquid out of one reservoir to open the interior of the other reservoir to atmosphere, thereby relieving the Ylatter reservoir of internal pressure and enabling it to be quickly drained of accumulated clear water preliminarily to its being refilled with the foam-forming solution.

A still further object of the present invention is to provide a dual construction of pressure proportioner for producing lire extinguishing foam wherein the two reservoirs for the foam-forming liquid are horizontally spaced in a single container and wherein the control means hereinbefore referred to is constructed in the form of a unitary assembly which is adapted to be quickdetachably connected in operative relation to the dual reservoirs of the apparatus.

While it is generally an object of the present invention to provide a readily Operable control mechanism for a dual pressure proportioner unit irrespective oi whether it be ci the type having vertically spaced reservoirs or of the type having horizontally spaced reservoirs as hereinafter specifically disclosed, it is a special object of the present invention to provide a unitary control means which includes as component parts thereof all of the essential valves and tubes for controlling and directing the supply of water under pressure into and the delivery of roaming liquid from each of the two reservoirs in alternating sequence.

Still other objects and advantages ci the present invention, such as the provision cf a unit which is exceedingly compact and simple in construction, which is readily portable and easily operable without requiring the constant attendance ci an operator and which is extremely eincient in use, will appear more fully hereinafter, it being understood that the invention consists substantially in the combination, construction, location and relative arrangement o i parts, all as will .-be described in detail hereinafter, shown in the accompanying drawings and as nnally pointed out in the appended claims.

In the said accompanying drawings, which illustrate a preferred embodiment of the present invention: Y

Figure l is a top plan view of the apparatus embodying the present invention;

. Figure 2 is an elevational View thereof;

1ligure 3 is an end View thereof;

Figure is a sectional View Yoi the water conduit and valve assembly;

. Figure 5 is a sectional View taken on line 5--5 of Figure 4;

Figure 6 is a sectionalview taken Online 5,--2'3 of Figure e; and p Figure 'l is a sectional view cfaV detail of the valve assembly taken on the line 'l-i of Fig-v ure Ll.

Referring now to the drawings and more .particularly first to Figures l to 3, inclusive, it will be observed that the control means of the present invention, designated generally by the reference numeral 24, is shown operatively associated with a supply tank lll for the foam-forming material, this tank being disposed horizontally and being provided internally thereof with a central partition l l to form a pair of separate chambers l2 and i3 for the foaming liquid. Preferably, the partition ll is arched, as are the opposite ends of the container lll, to strengthen the chambers against the relatively high pressures developed therein during the operation of the apparatus.

, The container lil is provided with a pair of iilling pipes i6 and ll for filling the chambers l2 and i3, respectively, with foam-forming liquid, these filler pipes being respectively provided with closure caps i8 and I9. Preferably, each of the chambers l2 and E3 is vprovided internally thereof with lling chutes 20 and Zea which are operatively associatcd with the filling tubes i@ and Il (see Figure 3) to facilitate filling of the chambers l2 and i3 with the foam-forming material with a minimum of splash and agitation thereof. In addition, each of the chambers I2 and 3 is `provided with a drain iitting 2| equipped with a closure cap Z2.

Provided in the top of the container lll in the immediate region of the central partition Il is a collar 23 having a, single opening therethrough which is common to both of the chambers l2 and l. In other words, a portion of this opening is disposed to one side of the partition ll and communicates with one of the chambers, while another portion of this opening is disposed to the other side of the partition ll and communicates with the other chamber. 1n this connection, it will be observed that the partition member Il is provided wtih an annular flange lla which is welded or otherwise secured to the inner wall surface ofthe drum or container ID, the ange Ha being suitably cut out within the area defined by the collar 23 to provide a free passage through said flange ilil which is in registry with the bore of the collar 23.

Referring now more particularly to Figures 4, 5 and 6, which shows the details of construction of the unitary valve control mechanism, designated generally by the reference numeral 24, it will be noted that this unit essentially consists of a tube through which water is delivered under suitable pressure from a source of supply to a point of discharge, this tube including a Venturi passage and having associated therewith a valve lor controlling the passage of water therethrough and additional valve means for diverting a p0rtion of the main Water stream into one or the other of the chambers l2 and I3, as desired, for imposing upon the foam-forming liquid contained in said chamber a head of pressure sufcient to force the liquid out of the chamber and inject it into the stream of Water as the latter passes through the low pressure section of the Venturi passage.

' More specically, theunit 24 essentially consists of a main body member 25 generally in the form of a longitudinally extending tube having a bore 2E extending therethrough. This bore is provided with an inlet tting 21 and with a discharge fitting 28 and is formed intermediate of its length to provide a Venturi passage 29 through which a stream of water from a suitable source of high pressure supply is adapted to be projected in the direction indicated by the arrows. It will be understood, of course, that the water inlet end of the unit is adapted to be connected by way of the iitting 2 and a hose (not shown) to a hydrant or other source of water under suitable pressure, while the outlet or discharge tting 28 of the unit is adapted to be connected to a hose (not shown) through which the water mixed with a foam stabilizer solution is delivered to the point where airis entrained therein and thence' discharged in the form of lire extinguishing foam. The manner of and means for effecting the entrainment of air or other gas into the stream of water laden with the foam-forming substance forms no part of the present invention, and, no detailed description thereof will be given herein, the present invention being limited more particularly to the control means for introducing into the Water stream the requisite quantity of the foam stabilizing solution. It will be understood in this connection that this invention is `not limited to the use of any particular type of foam-forming material. Usually this masecondary extract of licorice, of saponin or of other suitable substance having the capacity of being foamed when a gas is injected into a solution or suspension thereon Included in the unit 2d as component parts thereof are a pressure gauge 3U and a main water valve 3l, both of which are located in advance of the Venturi passage 29. The water valve 3l, which may be of any suitable type for interrupting the flow of water through the bore 26 of the unit, is adapted-to be operated by a handle 32.

In addition to the Venturi passage 29 extending longitudinally through the injecting unit 24, the latter is provided with a valve body 33 formed as an integral extension of the body portion of the unit in which is formed the Venturi passage. This valve body 33 is provided with a tapered bore 3d extending longitudinally therethrough and in this tapered bore is fitted a valve plug 35. This valve plug 35 is provided at its reduced end with a threaded stud or shank 36 for reception of a.

cap nut el by means of which the valve plug 35 is drawn snugly into operative position within the tapered bore 3d of the valve body. Preferably, a coiled compression spring 38 is interposed between the cap nut 31 and the valve body so as to impart a bias upon the valve plug operative normally to maintain it in operative position axially of the valve body while permitting it to kbe rotated freely about said axis in one direction or the other by means of an operating handle 39.

The valve body 33, in the region of the high pressure portion i8 of the Venturi passage, is provided with a pair of laterally spaced passages di and 42 (see Figure 5), the upper ends of which commonly communicate with the longitudinally extending bore 3d of the valve body 33 and thence with the portion de of the Venturi passage by way of a central vertical extending passage d3. The lower ends of these passages 4I and d2 are respectively in communication with the chambers I2 and I3 and to this end are in registry with the portions of the opening through the collar 23 in the top of the container in which are disposed to either side of the central partition II. The valve plug 35 is provided upon opposite sides thereof with arcuately shaped grooves or passages dll and l5 which are adapted respectively for registry with the passages il and d2 (see Figure 5) so that as said valve plug 35 is rotated in one direction or another, free communication is effected between the interiors of either one of the chambers I2 and I3 with the high pressure portion en of the conduit leading into the Venturi passage 29.

position as sho-wn in Figure 5, the high pressure portion lo of the water passage through the inlector unit is in free communication with the chamber I2, in consequence of which a portion of the water stream flowing through the unit from its source of supply may be diverted intoy the said chamber i2 in the direction of the full line arrows, as indicated in Figure 5. other hand, when the valve body is rotated into the dotted line position shown in Figure 5, a portion of the said water stream is divertedinto the chamber I3, as indicated by the dotted line arrows of Figure 5. Of course, when the valve plug 35 assumes a central position so as to close off completely the central passage d3, no water is diverted out of the main stream into either of the chambers I2 and I3 and the water stream in its entirety is projected straight through the Venturi passage 2d.

As also most clearly appears in Figures 4 and 5,

On the water passages id and i5 previously described.

the valve body 33 is provided with a vent 4S to atmosphere, this vent being located substantially in the transverse plane of the passages 4I and A2 and being adapted to vent one or the other of the chambers I2 and I3 to atmosphere depending upon the position of the valve plug 35.

Thus, when the valve plug 35 is in the full linev position shown in Figure 5, the chamber I3 will 'be vented to atmosphere, while conversely, when the valve plug35 is in the dotted line position shown in Figure 5, the chamber I2 will be vented to atmosphere.

The valve body or casing .t3 is Provided with a second pair ofv laterally spaced passages il and d3 spaced axially from the previously described pair of passageslli and d2, these passages il and i3 being disposed substantially in a transverse plane intersecting the low pressure portion 49 of the Venturi passage 29. These passages il and i8 also communicate at their upper ends with the longitudinal bore 3d of the valve casing and thence by way oi a common vertically extending passage 5@ with the low pressure portion i9 of the Venturi passage. rEhe lower ends of these passages and are respectively connected to a pair of delivery tubes 5I and 52 for the foamforrning liquid, these tubes being respectively projectedinto the chambers l2 and i3 with their open ends terminating jus., above the bottoms of said chambers (see more particularly Figure 2),

Adapted for respective registry with the pasil and t8 are a pair of passages 53 and 513 formed in the plug body 35, these latter passages being similar in all material respects with the It will be apparent that when the plug body 35 is in the full line position shown in Figure 6, the interior of the cham-.ber i2 is in free communication withthe low pressure section i5 of the Venturi passage by way of the delivery tube 5l, the passage fil', the passage '53 and the passage 5x1, while when the valve plug 35 is in the dotted line position shown in Figure 6, the interior of the chamber i3 will be in free communication with the bore fifi of the injector unit by way of the tube 5I?. and the passages d8, 5d and Eil. There is no atmospheric vent associated with any of the last mentioned passages.

The injector unit as hereinbefore described, is preferably provided with a mounting plate or flange 55 which fits upon the collar 23 and is bolted thereto by means of suitable bolts or other securing elements 5e (see Figure l). As has been previously indicated, the delivery tubes 5I and 52 for the foaming solution may be fitted in the injector unit as component parts thereof and the unit, including such tubes, may be attached to or removed from the tank IQ as an entirety. In order to facilitate this, the tube 5I may be bent to conform generally to the curvature of the partition I i so that when the unit is mouned in position, the tubes are disposed to either side of said partition. Of course, it is within the purview of the present invention to form the tubes as component parts of the container I!! rather than of the injector unit, in which case any suitable means may be provided for establishing tight communications between the upper ends of the tubes '5i nd 52 and the passages @l and i8 of the injector unit when the latter is mounted securely in place.

ln order to insure against the valve plug 35 bccoming so bound in the bore 34 of the valve body so that it becomes difficult to rotate it into" one or another of its operative positions, the end thereof to which the operating handle 39 is secured is extended outwardly of the valve body and this outwardly extending portion is slotted, as at 51, to receive the bar 58 of the operating handle. This bar E8 is pivoted to the slotted portion of the plug l5 by a transversely extending pin 59, the aperture 'de in the bar 'being of somewhat greater diameter than that of the pivot 59 to provide for a certain amount of play between the pivotally connected parts. Also, the lower end of the bar S of the operating handle projects downwardh7 below the plug for engagement with the stationary part si of the valve body when the handle 39 is swung in counter-clockwise direction about its pivot pin when viewed as in Figure 4.

It will be apparent that when the handle is so swung in counter-clockwise direction, the fixed part 6l of the valve body which is engaged by the lower extremity of the operating handle serves as a fulcrum about -which the handle In the operation of the apparatus of the presi ent invention, it will be assumed that the chambers I2 and i3 are each filled with the requisite foam-forming liquid and that the apparatus is connected to a source of water supply under suitable pressure by way of the fitting 21 and to a foam-forming and discharge conduit by way of the tting 28. Normally, the handles 32 and 39 will be in their inoperative positions, that is, in

positions whereby the main water valve 3l and .1:

the foam injecting valves are all closed. TVhcn it is desired to place the apparatus in operation, the handle 32 is operated to open the valve 3l and so permit the passage of water under pressure trom its source of supply through the bore 26 of the foam injecting unit. It will be understood, of course, that so long as the handle 39 remains in its closed position, no water will be diverted into either of the chambers l2` and I3 and consequently, no foaming liquid will be delivered therefrom for injection into the water stream. When it is desired to produce foam for nre extinguishingpurposes, the handle 39 is moved to either one of its two extreme positions. Assuming that both chambers i2 and i3 are filled with foam- 1 forming solution, it would, ci course, be immaterial in which direction the control handle 39 is thrown. Assuming this handle to be thrown into position to rotate the valve plug 35 into the full line positions shown i-n Figures 5 and 6, the portion of the water stream owing through the injector tube would be diverted from the portion 4B thereof into the chamber I2 by way of the passages 3, 44 and 4|. The water so diverted into the chamber I2 immediately exerts an even pressure upon the entire upper surface of the foam solution contained in said chamber, the passages dell and 4! being of such substantial size that substantially the full head of water pressure is so exerted upon the foam stabilizer solution in said chamber. Due to the fact that the delivery tube 5I for the foamiorming liquid is in free communication with the low pressure portion of the Venturi passage by "way of the passages 67 and 59 (see Figure 4),

there exists a pressure differential which results in the dow of the foam solution upwardly through the tube 5l and the passages el and 53 into the stream of water flowing through the low pressure portion of the Venturi passage. This flow of foam solution from the. chamber l2 into the stream of water iiowing through the Venturi passage of the injecting unit will continue, of course, so long as the stream of water under suitable pressure is flowed through the unit and until the supply of foam solution in the chamber l2 is .completely exhausted. inasmuch as the iiow of the foam solution upwardly through the tube 5I is dependent upon the pressure diierential existing between the high and low pressure portions of the Venturi passage, it will be apparent that by proper design of the cross-sectional areas of the high and low pressure portions of the Venturi passage, the ratio of the rate of iiow of the foam solution to the rate oi :dow oi the water stream through the Venturi passage may be predeterminedly established and maintained.

Having exhausted the supply of' foam-forming solution contained in the chamber l2, in order to continue the production of foam, it is merely necessary to reverse the position of the control handle 39 so as to rotate the valve plug 35 into the dotted line position shown in Figures 5 and 6. In this position of the valve plug 35, exactly the same conditions will obtain as described in connection with chamberl2 for effecting the delivery or the foam-forming solution from the chamber i3 into the water stream flowing through the injector tube. At the same time, the chamber i2 which has been exhausted of foam-forming solution and is now lled with water under suitable pressure, is automatically vented to atmosphere by way of the vent d@ so as to relieve said chamber of such internal pressure and to facilitate the discharge' of the water therefrom by way of its drain 2l. Having removed all of the clear water from the chamber i2, it may now be relled with foam-forming solution by Way of its filling pipe i6 so as to provide a further supply of foaming solution which is ready to be used immediately upon exhaustion of the supply in the chamber i3. Obviously, this cycle of operation may be continued so that the requisite quantities of foam may be produced substantially uninterruptedly until the nre is extinguished.

It will be understood, ci course, that the invention is capable of various changes and modifications which may be made from time to time without departing from the real spirit or general principles thereof, and it is accordingly intended to claim the invention broadly as well as specifically as indicated in the appended claims.

What is claimed as new and useful is:

i. An apparatus for injecting foam-foaming material into a owing stream of water comprising, in combination, a tank having a pair of independent chambers respectively adapted to contain separate supplies of foam-forming material, the said tank having an opening common to said chambers and disposed to provide direct access to each of said chambers, and a unitary water conduit and valve assembly mounted over said opening and including means for selectively controlling the flow of foam-forming material to said water conduit alternately from said chamhers as desired and ior diverting a portion of the water into that one oi the chambers from which the foam-forming material is drawn whereby to subject the material in said chamber to a diierential pressure to eiect its from said chamber.

2. An apparatus for injecting foam-forming material into a flowing stream of water comprising, 'in combination, a tank having a pair of independent chambers respectively adapted to contain separate supplies of foam-forming material, the said tank having an opening common to said chambers for providing direct access to each of said chambers, and a unitary water conduit and valve assembly mounted over said opening and having means for selectively controlling the flow of foam-forming material to said water Conduit alternately from said chambersas desired, said assembly including a Venturi passage and a pair of delivery tubes for the foam-forming material extending respectively from the low pressure portion of said Venturi passage to the bottoms of said chambers and including also means for diverting a portion of the water from the high pressure side of the Venturi passage to one or the other of said chambers as desired to subject the material contained therein to a differential pressure sufficient to effect its discharge from said chamber into the iiowing stream of water.

3. An apparatus for injecting foam-forming material into a owing stream of water comprising, in combination, a tank having a pair of chambers respectively adapted to contain separate supplies of foam-forming material, the said tank having an opening common to said chambers for providing direct access to each of said chambers, and a unitary water conduit and valve assembly mounted over said opening, said assembly including means for establishing a pressure difierential between spaced portions of said water conduit, valve means for connecting the high and low pressure portions of said water conduit with either one of said chambers whereby to subject the material contained therein to a diierential pressure suiiicient to eiect its discharge into the low pressure portion of the flowing stream delivery of water, and means for selectively controlling the discharge of the foam-forming material alternately from said chambers as desired.

4. A water conduit and valve assembly for the delivery of foam-forming material selectively from either of two independent sources of supply into a continuously iiowing stream ofwater comprising a water conduit having a Venturi passage therein to provide a pressure differential between spaced portions of said conduit when water under pressure flows therethrough, and valve means for connecting said spaced portions of the conduit selectively with either of said sources of supply of the roam-forming material.

5. An apparatus for eiecting continuous introduction of a foam-forming sclution derived from one of two separate sources of supply into iiowing stream of water comprising a unitary water conduit and valve assembly including a main valve for controlling the iiow of water through said conduit and an auxiliary valve operable selectively to divert a portion of the Water stream to one or the other of said sources of supply of the foam-forming solution for subjecting the same to a positive head of pressure and to connect the source of supply so subjected to pressure to said conduit at a point located beyond that where the water is diverted to said source of supply.

6. An apparatus for effecting continuous introduction into a iiowing stream of water of a foam-forming solution derived from one of two separate conned sources of supply comprising a main water conduit having a Venturi passage therein, a main valve for controlling the iiow oi water through said conduit, means for selectively connecting the high pressure portion of said Venturi passage with one or the other of said sources of supply whereby to subject the same to water under pressure diverted from said flowing stream, means for selectively connecting the low pressure portion of said Venturi passage with one or the other of said sources oi supply whereby to effect the dischargetherefrom of the foamforming solution into the flowing stream of water under the influence of the diverted water under pressure, and means for effecting simultaneous operation of the two last-mentioned means.

7. An apparatus for eiecting continuous introduction into a flowing stream of water of a foam-forming solution derived from one of two separate conned sources of supply comprising a water conduit having4 a Venturi passage therein and a multiple valve unit operatively associated therewith, said valve unit including a pair of passages selectively adapted to establish communication between the high pressure portion of said Venturi passage and either of said sources of supply and a second pair of passages selectively adapted to establish communication between the low pressure portion of the Venturi passage and either of said sources of supply.

8. An apparatus for effecting continuous introduction into a flowing stream of water of a foam-forming solution derived from one of two separate confined sources of supply comprising a water conduit having a Venturi passage therein and a multiple valve unit operatively associated therewith, said valve unit including a pair of passages selectively adapted to establish communication between the high pressure portion of said Venturi passage and either of said sources oi supply and a second pair of passages selectively adapted to establish communication between the low pressure portion of the Venturi passage and either of said sources of supply, and means for insuring that the high and low pressure portions of the Venturi passage are simultaneously connected to the same selected source of supply of the foam-forming solution.

9. An apparatus for effecting continuous introduction into a owing stream of water of a foamforming solution derived from one of two separate conned sources oi" supply comprising a water conduit having a Venturi passage therein and a multiple valve unit operatively associated therewith. said valve unit including a pair of passages selectively adapted to establish communication between the high pressure portion of said Venturi passage and either of said sources of sunplv and a second pair of passages selectively adapted to establish communication between the low pressure portion of the Venturi passage and either of said sources of supply, and means operable to simultaneously change the connections from the high and low pressure portions of the Venturi passage from one to the other of said. sources of supply of the foam-forming solution.

10. An apparatus for effecting continuous introduction into a iiowing stream of water of a foam-forming solution derived from one of two separate confined sources of supply comprising a water conduit having a Venturi passage therein and a multiple valve unit operatively associated therewith, said valve unit including a pair of passages selectively adapted to establish communication between the high pressure portion of said Venturi passage and either of said sources of supply and a second pair of passages selectively adapted to establish communication between the low pressure portion of the Venturi passage and either of said sources of supply, and means for automatically venting to atmosphere that one of said confined sources of supply `of the foam-forming solution which is shut off from communication with the water conduit.

11. An apparatus for eiectin'g continuous introduction into a flowing stream of water of a foam-forming solution derived from one of two separate confined sources of supply comprising a main water conduit having a Venturi passage therein and valve means operatively associated therewith for selectively establishing communication between said conduit and one of said .sources of supply, said valve means including a valve body having axially spaced sets 'of passages, one set of passages being in communication with the high pressure portion and the other set in communication with the low pressure portion of said Venturi passage, and plug means in said valve body having passages adapted to selectively connect corresponding passages of said axially spaced sets with one of said sources of supply whereby vto subject the same to a differential pressure adequate to effect delivery of they solution into the flowing' stream of water at the low pressure side of the Venturi passage.

12 12. An apparatus for effecting continuous introduction into a flowing stream of water of a foam-forming solution derived from one of two separate conned sources of supply comprising a main water conduit having a Venturi passage therein and valve means operatively associated therewith for selectively establishing communication between said conduit and one of said sources o1" supply, said valve means including a valve body having axially spaced sets of passages, one set of passages being in communication with the high pressure portion and the other set in communication with the low pressure portion of said Venturi passage, and'plug means in said valve body having passages adapted to selectively connect corresponding passages of said axially spaced sets with one of said sources of supply whereby to subject the same to a differential pressure adequate to eiect delivery of the solution into the flowing stream of Water at the low pressure side of the Venturi passage, said valve means including means to vent to atmosphere that source of supply of the foam-forming material which is not in communication with the water conduit.

FRANCIS J. HOGENMILLE-R.

FISHER L. BOYD.

LEWIS W. BOERNER.

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