US2249095A - Apparatus for producing fire foam - Google Patents

Description

July 15, 1941. c. K. SWIFT ET AL 2,249,095 I APPARATUS FOR PRODUCING FIR E FOAM Filed April 14, 1959 ported and due,

of fire and which Patented July l5, 1941 stares PATENT OFFlCiEl 2,249,t APPARATUS FOR PRODUCING rmr. FOAM Clement K. Swift, Upper Darby, Pa., and John' B.

Treiehel, Audubon, N. 'J., drews & Forbes Company,

assignors to MacAn- Camden, N. J., a

corporation of New Jersey Application April 14, 1939, Serial No. 267,886

5 Claims.

stabilizers.

fPriorto' the present invention the production of mechanical or air fire extinguishing foams for the most part involved the use of foam produc-- ing substances or stabilizers in aqueous orvother solution. This practice involves certain relatively serious restrictions in the production and use of the foam due to the necessarily large bulk and weight of the material required to be transalso, to the relatively high cost of containers and the like for such materials. Furthermore, a particularly serious limitation and objection to the use of foam producing substances or stabilizers in solution is their susceptibility to freezing. ing foams of the type generated by chemical means are subject to breakdown after relatively short time, and cannot be conveyedby means of hose or pipes to remote points without serious loss .of volume and quality. I

With the foregoing observations in mind, the principal object of the present invention is to provide a novel apparatus wherein a dry foam producing agent or stabilizer is continuously proportioned and mixedwith water and a suitable gas, and then agitated to produce a fire extinguishing foam of superior quality. Another object of the invention is to provide a novel apparatus for producing a fire extinguishing foam which is highly stable in the presence.

will not break down for comparatively long periods of time and which may be conveyed to points substantially remote from the point of generation without detrimental effect to its structure or volume.

Another object of the invention is to provide a novel apparatus for producing fire extinguishing air foam from a dry foam producing composi-' tion which normally is not readily soluble in water.

.Another object novel method of producing a fire extinguishing foam which is not only effective against gasoline and other petroleum product fires, but which is also highly effective against burning alcohol and similar extra hazardous combustible liquids.

- Still another object of the invention is to provide an apparatus for producin fire extinguish-.

of the invention is to provide a In addition, fire exti'nguishproperties the present invention ing foam of the character described which apparatus is comparatively compact and portable, and capable of delivering the foam to a hose line or system of pipes under pressure sufficient to 'convey said foam, or project the same from a hose nozzle, for substantialdistances.

A further object of the invention is to provide an apparatus for producing fire extinguishing foam of the type described, which apparatus is constructed and arranged to effect positive, easy and rapid adjustment of the fluidity and other and characteristics of the foam.

These and other objects of the invention and the various details of construction and operation involved therein are hereinafter fully set forth and shown-in the accompanying drawing in which:

Figure 1 is a view in elevation partially in secapparatus contemplated by for carrying out the-method tion of one form of thereof.

Figure 2 is a view in section taken on line 2-2, Figure l; and

Figure 3 is a view similar to Figure 1 illustrating another form of apparatus for producing fire extinguishing-foam in accordance with this invention.

Referring now more particularly to Figure 1 of the drawing, the apparatus there illustrated comprises a base or supporting structure I on which is mounted a support 2 for a water supply tank or reservoir 3, a standard 4 for supporting a device designated generally as 5 for feeding a dry foam producing'compos'tion, and a rotary pump or compressor designated generally as 6.

The rotary pump or compressor 6 is of the so-called water-ring type (such as the Nash type) and comprises a rotor I having blades 8 which revolve freely within an eliptical casing 9 in hydraulic balance. The casing 9 is provided with the requisite main inlet and discharge ports l0 and II, respectively, and additional inlet ports 12 and I3, respectively, open to therotor chamber from the casing while outlet ports I l and I5 exhaust from said rotor chamber to the casing 9 and its main discharge port H. More specifically, and as shown in the drawing, the chamber of this compressor end portions and a relatively contracted midportion defined by the continuousinner walls of the chamber, and in this mid-portion is located a power-driven rotor having substantially radial blades, the ends of which are curved in the direc- The blades of the rotor has longitudinally elongatedchamber walls at the contracted mid-portion of said chamber and the contour of said walls defines a correspondingly shaped path of movement under the impetus of the rotor blades thus affording the violent agitation essential to production of a satisfactory and stable fire extinguishing foam. x

In the drawing, the discharge port ll of the pump 6 has connected thereto a hose or the like l6 having a nozzle I! at its outer end, but in lieu of said hose and nozzle it will be obvious that said pump discharge port ll may have a pipe or system of pipes (not shown) connected thereto by means of which the foam discharged from the pump 6 may be conveyed to one or more relatively remote points.

Connected to the main inlet port ID of the rotary pump 6 is one end of a feed or supply pipe l8, the other end of which is connected to the lower end of a pipe or tube l9 secured axially and vertically within a tank or vessel 20. The tube or pipe I9 is provided with a plurality of apertures 2| therein which extend upward to a point above the tank or vessel 20 where its walls diverge outwardly to forma funnel-shaped inlet 22 for air or other gaseous medium and the dry foam producing composition.

This foam producing composition is fed into the funnel-shaped inlet 22 and pipe or tube l9 by means of the'feeding device mounted upon the standard 4. The feeding device 5 comprises a hopper 23 for the dry foam composition and at the lower end or bottom of this hopper 23 is a table or disk 24 secured on a rotatably mounted vertical shaft 25. The shaft 25 extends an appreciable distance upwardly within the hopper 23 and fingers 25a are secured thereon above the table or disk 24 so as to rotate with saidshaft 25 and maintain and keep the dry foam composition relatively loose and free to insure proper feed thereof.

Rotation of the feed table or disk 24 may be 4 accomplished in any suitable manner, for example, as shown in the drawing by providing gear teeth 26 on the underside thereof for engagement by the teeth of a spur gear 21 which maybe driven from a motor 28 either directly or through a belt and pulley system 29 as shown. Discharge or feed of the dry foam com osition is effected by revolving or rotating the able or disk 24 to move the material thereon past a feed knife-or the like 30 which deflects or directs said material through the discharge opening 3| from which it falls or drops into the upper funnelshaped end 22 of the tube or pipe l9. As shown in Figure 2 of the drawing, the feedknife 30 is adjustable about its pivot 32 to control the width of the discharge opening 3| and thereby control the rate of feed or discharge of the foam agent or stabilizerr ,Water for mixture with .the air and dry foam producing composition is supplied to the tank or vessel 20 through a pipe 33 which leads from the bottom of the reservoir-3 a d is connected to said tank 20 adiacent its lowe end, said pipe 33 being provided .with a valve 34 for controlling the passage of water therethrough to the said tank 20. Water is supplied to the reservoir 3 through a pipe 35 underthe control of a valve 36 operated by a float 31 whereby the water in said reservoir3 is maintained at a predetermined constant level. from the pipe 35 and connects with the chamber of the pump 6 as at 44, and this pipe 43 is con- In addition, a pipe 43 leads trolled by a valve 45 so that in instances when '75 vortex .38.

In operation of the apparatus'eto produce fireextinguishing foam according to the present invention, air or other gaseous medium is drawn by the rotary pump 6 inwardly of the funnel 22, and pipes I9 and I8 to the main inlet port l0 thereof. At the same time, rotation of the table or disk 2 of the feeding device 5 discharges the dry foam composition into said funnel 22 with the inflowing air stream at a predetermined substantially uniform rate of feed. Likewise water entering the tank or vessel 26 fromthe reservoir 3 enters the tube or pipe I9 through the apertures or perforations 2| therein and mixes with the air and dry foam composition before entering the rotor chamber of the pump 6 through the secondary inlet ports l2 and I3, where it is mechanically generated into a highly stable air foam and discharged at pressures sufiicient to enable it to be conveyed or projected for substantial distances.

It will be observed in the arrangement of apparatus illustrated in Figures land 2 of the drawing, that the dry foam producing composition is fed into th inflowing air stream prior to contact or mixture with the water which enters the tube or pipe l9"through its apertures 2|. Figure 3 of the drawing, a different arrangement of foam generating apparatus is shown whereinthe foam producing composition isfed to and mixed with the inflowing water stream.

This latter method of feeding the dry foam composition may be accomplished in several different ways, however, in that shown in Figure 3 of the drawing, the water reservoir may be entirely eliminated arid the water supplied directly to a vortex mixer 38 through a.branch pipe 39a under control of a valve 40, the branch pipe 39a connecting with a supply pipe 39 as shown. Also connected with the supply pipe 39 is a second branch pipe 39b controlled by. a valve 46 and connected to the pump 6a so that by operation of thevalves 40 and 46 the relative amounts of water admitted to the vortex 38 and directly to said pump 6 may be controlled. The pipe 39a is arranged so that the water is discharged into the vortex 38 tangentially thereof so that there results a swirling or whirling action as indicated by the arrows.

In this form. of apparatus the dry feeding device 511 may be the, same as that described above in connection, with Figure 1 having a hopper. 23a, and a feed table 24a driven by a motor 28a, said feeding device being mounted upon a standard 411 resting or secured upon 'a base la. As shown in the drawing, the dry foam producing composition is discharged from the feed table 24a and allowed to fall or drop into the vortex mixer 38 where it mixes with the water therein and subsequently flows with said water through the pipe ifia which leads from the bottom of the In this arrangement an air'inlet conduit 4| is connected to the main inlet Illa of the pump 6aand this conduit. gradually increases in diameter outwardly from the pump terminating in an upwardly directed mouth 42. The pipe I So. leading from the vortex 38 extends inwardly of this air inlet conduit '4! and terminates just short of the pump inlet l Oa'so that On the other hand and referring now to the suction created by said pump and the flow of the water and dry composition into the pump from pipe l9a draws air from the atmosphere inwardly of the said conduit 4| and entrains it into said pump 6a. The outlet Ha of said pump has connected thereto 'a hose or pipe line Ilia and nozzle Ila, as described in connection with Figure 1 of the drawing.

Still other methods may be employed involving the mixture of water and dry foam composition before contact with the inflowing air stream and, for example, in installations requiring further mixture and dilution of the dry foam composition, an ejector may be disposed in the'pipe Mia and supplied with waterat medium pressure so that the dry foam producing composition is hydrated and mixed with some water in the vortex mixer 38 and is then transferred, by means of the ejector, to the pump 6a, said ejector functioning to effect additional mixture and dilution of the dry composition. 7

In practicing the invention, a number of foam producing materials or substances such as saponin, licorice extract, extract of tan bark and the like may be successfully employed with or without an alkaline earth oxide. However, we prefer to use a mixture of licorice extract and an alkaline earth oxide (hydroxide) in dry powdered form. In this mixture the licorice extract may be either primary or secondary, and the oxide (hydroxide) is preferably calcium, barium or strontium. The percentages of licorice extract and alkaline earth oxide may vary widely but the oxincorporated in said invention within the scope of the annexed claims.

We claim:

1. Apparatus for producing fire extinguishing foam of the mechanical or air type from a frothing constituent, a gaseous constituent and an aqueous constituent, comprising means having an inlet and an outlet operable violentlyto agitate saidconstituents to generate foam and simultaneously place the same under substantial pressure, said agitating means comprising a waterring compressor including a chamber having longitudinally elongated end portions and a relatively contracted mid-portion defined by continuous internal walls of said chamber, a powerdriven rotor located in said mid-portion, blades on and, extending substantially radially from said rotor with the outer ends of the blades describing ide is preferably present in the mixture in proportions of from 10% to 50% depending upon the pump in relation to the feed of dry foam. composition. y

Thus the relative quantities or proportions of air, water and dry foam composition-will vary with the quality of foam desired, and using a generator or-pump designed to produce foam at a rate of one hundred, (100) gallons per minute, excellent results were obtained by feeding the dr composition at the rate of from one to two pounds per minute and water at the rateof from ten to twenty gallons per minute. The dry foam composition consisted of equal parts by weight of dry pulverized quicklime (calcium oxide) and dry powdered secondary licorice ex ract. The resulting foam is more or less fluid but a relatively stiif foam for use on vertical or inverted surfaces was produced by increasing the rate of feed of the dr powdered foam composition to as much as from four to five pounds per minute, maintaining the rate of feed of the water as above. In,

each instance the pump or, compressor was driven at a speed of 3700 R. P. M. and the discharge pressure in the foam line was between ten and forty pounds per square inch depending upon the size and length of the foam piping employed.

The invention is not limited to the use of the particular type of dry feeding mechanism illustrated and described herein and We may, for exfor feeding said frothing and aqueous constituents uniformly in predetermined proportions continuously to said conduit in which they are "pre-. liminarily mixed with each other and said gaseous constituent and then conveyed by said conduit directly to. the agitating means.

2. Apparatus'for producing fire extinguishing foam of the mechanical or air type from a frothing constituent, a gaseous constituent and an aqueous constituent, comprising means having an inlet and an outlet operable violently to agitate said constituents to generate foam and simultaneously place the same under substantial pressure, said agitating means comprising a water-ring compressor including a chamber having longitudinally elongated end portions and a relatively contracted mid-portion defined by continuous internal walls of said chamber, a powerdriven rotor located in said mid-portion, blades on and extending substantially radially fromrsaid rotor with the outer ends of the blades describing a circle substantially tangent to said walls at the mid-portion of said chamber, the contour of said continuous walls defining a correspondingly shaped endless path of movement for said mixture under the impetuslof said blades, a gaseous induction conduit connected at one end directly to the inlet of. said agitating means, means for feeding said frothing and aqueous constituents uniformly in predetermined proportions continuously to said conduit in which they are preliminarily mixed with each other and said gaseous constituent and then conveyed by said conduit directly to the agitating means, and a foam distributing system connected directly to the outlet of said agitating means.

3. Apparatus for producing fire extingu'shing foam -of the mechanical or air typefrom a ir othing constituent, a gaseous constituent and an aqueous constituent, comprising means having an inlet and an outlet operable violently to agitate saidconstituents to generate foam and simultaneously place the same under substantial pressure, said agitating means comprising a waterring compressor including a chamber having longitudinally elongated end portions and a rela tively contracted mid-portion defined by continuous internal walls of said chamber, a powerdriven rotor located in said mid-portion, blades on, and extending substantially radially from said rotor with the outer ends of the blades describing a circle substantially tangent to said walls at the mid-portion of said chamber, the contour of said continuous walls defining a correspondingly shaped endless path of movement for said mixture under the impetus of said blades, said outer ends of the blades being curved in the direction of rotation of the rotor to increase agitation of the mixture moving along said path, a gaseous induction conduit connected at one end directly to the inlet of said agitating means, and means for feeding said frothing and aqueous constltuents uniformly in predetermined proportions continuously to said conduit in which they are preliminarily mixed with each other and said gaseous constituent and then conveyed by said conduit directly to the agitating means. i

4. Apparatus for producing fl-re extinguishing foam of the mechanical or air type from a frothing constituent, a gaseous constituent and an aqueous constituent, comprising means having an inlet and an outlet operable violently to agitate said constituents to generate foam and simultaneously place the same under substantial pressure, said agitating means comprising a waterring compressor including a chamber having longitudinally elongated end portions and -a relatively contracted mid-portion defined by continuous internal walls of said chamber, a powerdriven rotor located in said mid-portion, blades ao ion and extending substantially radially from said rotor with the outer ends of the blades describing a circle substantially tangent to said walls at the mid-portion'of said chamber, the contour of said continuous walls defining a correspondingly shaped endless path of movement for said mixtureunder the impetus of said blades, said outer ends of the blades being curved in the 1 direction of rotation of the rotor to increase agitation of the mixture moving along said path, a gaseous induction conduit connected at one end directly to the inlet of said agitating means,

means for feeding said trothing and aqueous constituents uniformly in predetermined proportions continuously to said conduit in which they are preliminarily mixed with each other and said gaseous constituent and then conveyed by said conduit directly to the agitating means, and a foam distributing system connected directly to the outlet of said agitating means.

5. Apparatus for producing fire extinguishing foam of the mechanical or air type from a frothing constituent, a gaseous constituent and an aqueous constituent, comprising means having an inlet and an outlet operable violently to agitate said constituents to generate foam and simultaneously place the same under substantial pressure, said agitating means comprising a waterring compressor including a chamber having K longitudinally elongated end portions and a relatively contracted mid-portion defined by continuous internal walls of said chamber, a powerdriven rotor located in said mid-portion, blades on and extending substantially radially from said rotor with the outer ends of the blades describing a circle substantially tangent to said walls at the mid-portion of said chamber, the contour of said continuous wall defining a correspondingly shaped endless path of movement for said mixture under the impetus of said blades, a gaseous induction conduit connected at one end directly to the inlet of said agitating means, means for feeding said frothing and aqueous constituents uniformly in predetermined proportions continuously tosaid conduit in which they are preliminarily mixed with each other and said gaseous constituent and then conveyed by said conduit directly to the agitating means, and means for controlling the relative proportions of the frothing and aqueous constituents to regulate the fluidity of the foam produced.

L CLEMENT K. SWIFT. JOHN B. TREICHEL.

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