US1781300A - Apparatus for fire-foam production - Google Patents

Description

Nnv. 11, 1930.

P. w. PRUTZMAN 1,781,300 APPARATUS FOR'FIRE FOAM PRODUCTION Filed Sept. 28, 1927 IN ENTOP Patented Nov. 11, 1930 PAUL W. PBUTZMAN, h L08 GELES, CALIFORNIA APPARATUS FOR FIBIELZE OAM PRODUCTION Application filed September 28, 1927. Serial No. 222,589.

i The art .ofextinguishing fires in general, and particularly oil fires, by means of Foamg 1 its? or Firefoam is'very well known and qunderstood. It consists in bringing into ado mixture solutions of aluminum sulfate, hy-

drogen, sodium-carbonate (baking soda or I more briefly soda), and a stabilizer or sub stance having the property or" increasing the surface tension of aqueous liquids, such for instance as glue or licorice. It is customary to make one solution, lmown as the (a) or acid solution, of the aluminum sulfatealone, and another, known as the (b) or soda solution, of a mixture of soda and stabilizer and 5 to make these two solutions of-such strengths vthat their usein equal proportions will produce the largest yield of foam without wast- ;age of chemicals. p 7 .By the admixture of said ingredients in solutions of the propervstrength a very dense and tenacious foam is formed which, as it consists mainly of water and is sufiiciently, light to float on oil, is a highly efiicacious and valuable agent for extinguishing fires.

It has heretofore been the custom either to prepare the solutions in advance and distribute them by means of duplicate pipe lines to such parts ofa plant as require protection, or to store small quantities of the solutions in ressure tanks mounted on wheels, which can he taken to the seat of the fire. The first system isdisadvantageous in that the required investment is very heavy, and more particularly in that thecontents of the solution tanks is necessarily limited and the time re uired .for recharging them quite extended. t has often occurred that these tanks have become exhausted in the course of a stubborn fire, and that before they could be refilled the fire had gotten quite out of hand.

x The second system is disadvantageous in,

that the output in actual foam of the largest unit which canbe taken from one point to another is so trifling that these portable tank units can handle only the smallest fires.

An object of my invention is to provide a cheap and efi'ective means for the continu ous production of solutions of the foam chem;

icals from their dry salts, thus doing away m with the requirement for any storage of solution and avoiding a possible failure of solution during the course of a fire. In this view of my invention the apparatus is adapted to be used in connection with an existing system of duplicate distributing lines for solution. a

A further object of my invention is to provide a simple and efi'ective portable apparatus which can be taken to a point adjacent to the seat of the fire and there, being sup lied to solely with water and the two chemica s in bulk, will supply for an indefinite period streams of separate solutions of the two chem icals, which can be separately conducted to the actual fire and there intermixed in any B5 preferred form of mixing head.

Further objects and advantages of my invention will be evident from an inspection of the accompanying drawing in which- Fig. 1 is a view partly in elevation and partly in cross section, illustrating a comlete embodiment of my invention in a preerred form. F ig. 2 is a diagrammatic view of an orifice plate showing parts thereof broken away.

Referring to the drawing, numerals 1 and 2 indicate conical bottomed steel tanks for preparing respectively the a and b solutions. 3 is an inlet pipe for water from any convenient source of supply, and 4--4 are gauge marks for indicating a constant height to which the tanks are to be kept filled.

Pipe 3 branches into two pipes 5 and 5, controlled by the valves 6 and 6 and the meters 31 and 31 shown in such lines are 35 also convenient for determining the rate of flow of water, but are not essential. These pipes enter tanks 1' and 2 at substantially their bottoms, as indicated at 7--7, and beneath the umbrellas or inverted funnels 8--8. The upper ends of these funnels are made fast to the suction pipes 9"-9" but do not communicate therewith. The lower edges of the funnels are so formed as to closely approach the tank cones 10-10, leaving the annular openings 11-11 each of which should have approx mately the area of an inlet pipe 5.

The pump suction pipes 9"9 are made fast in the oints of the cones and rise to a height of a at six inches below the liquid level marks 4-4. These pipes communicate with the suctions of the rotary or other suitable pumps 12 and 12"., driven at equal speed as by the pulley 13 from a commonsource of power not shown. If the unit is to be port-= able this source of power-is preferably a de-' pendable high-speed throttling gasoline en-- gine, such for instance as the engine driving the truck on which the unit is mounted.

The pumps 12 discharge into lines l f --14 by which the solutions pumped out of tanks 1 and 2 are conveyed through the lines IS -15 (which may be of pipe, hose or both) to the mixing head.16 by WlllCh the solutions are intermixed, converted into foam and directed onto the fire.

Between the lines 1 1 and 15 are interposed a control valve 17 and a meter 18, the same fittings being correspondingly placed in the (2 lines. A bypass line 19 connects the dischar e line 14 with the water inlet 5, and in this bypass is placed the release valve 20 so connected as to carry any excess discharge of pump 12 back into tank .1. This bypass enables the pump to be run at constant speed rod 2424 and sliding in a cylinder 25-25. 4-4

The assembly of pistons and rod is recipro: cated by a single crank (or other suitable mechanism) 26 driven by a band wheel 27 at some suitable speed which is pro ortioned to the speed of the engines driving t e pumps.

In operation, these pistons, at the left end of their stroke, register the chambers 28-28 with corresponding openings 29 29 in the bottoms of hoppers 30 -30". At the right end of the stroke the openings 29 are closed and the powders contained in the chambers 28 are dumped into the corresponding chutes 3O-30 by which they are carried into tanks 1 and 2 respectively. It is considered advantageousto allow these powders to free themselves from air in the chutes 30 before passing into the bodies of liquid contained in the tanks, but they may if preferred be dumped directly into the tanks and the chutes omitted. The relative quantities of powder carried by each chamber 28 maybe varied by varying its length (without altering the piston stroke) or by wrapping a bulky material (such as rope or flax packing) around the rod.

It will be understood that this particular method of feeding the chemicals is not an essential part of my invention, and that other means, such as screw conveyors or small bucket, elevators may be used, provided they give a dependably constant feed-of each powder.

In the operation of my device the-following steps are taken. 'Water being connected to pipe 3, the valves 6 and 6 are opened until the meters 31 and 31 indicate the predetermined rate of fiow,'that is, the rate at which solutions will later be pumped from the tanks.

If-"the apparatus is to be used in a situation where the Water pressure is reasonably constant, time in starting will be saved by providing stopcocks with dials and pointers, located as at 32 32 which can be left in adjustment, the valves 6--6' being .then used as stop valves only.

At the time the water flow is started the feed of dry chemicals is started, these passrate of flow of solution through the pipes 159-15" to the mixing head 16. The final step is to readjust the water supplyby means of the stopcocks 32 until the liquid stands level in tanks 1 and 2 at the gauge marks These balancing up steps having been completed, the apparatus will continue to deliver, indefinitely, equal streams of solutions of correct strength, provided only that the hoppers be kept filled with their appropriate chemicals. At the termination of a run the tanks may be pumped empty by closing the water valves 6-6 and opening the drain valves 33-33 the feed of chemicals having meanwhile been stopped.

While the apparatus illustrated in the drawing has the appearance of a lar e and permanent set, and while it may rea ily be constructed in such size, I would have it understood that it may also be constructed of such dimensions as to make it readily portable. For illustration, a unit producing 100 allon's per minute of each solution, equivaent, when properly mixed, to 2000 gallons per minute of foam (the rate of expansion eing about ten to one), is suflicient to-handle a very large fire. Such unit would require two pumps havinga full speed capacity of say 125 gallons ppr about 150 pounds eac Tanks 1 and 2 should not have less than 1 minute capacity and preferably should holda supply for 2 minutes, or 200'gallons each. The dimensions of such tanks would be about 3' diameminute, weighing matically illustrated in Fig. 2, in

ter, 3' cone.

The reagents weigh about 1 pound per 23 cubic inches, and as gallons of a solution require 60 pounds and of 1) solution 40 pounds of reagent, a plunger 4 diameter making 20 strokes per minute would re quire an a chamber 6 long and a b chamber 4" long.

The water inlet main 3 should be say 3" diameter, branching to two 2 pipes, and the solution outlets should be 2 pipe size. The entire apparatus, including pumps,

4" height on side and 2' height of weigh, readily small truck for trans- As replacingthe control of the volumes of solutions and of water by means of valves and meters as shown, it is permissible, and is often a desirable modification of my invention, to pass these solutions through orifice plates (as indicated at 18 and 18 in Fig. 1) calibrated to deliver the required or preferred quantities of liquid at a certain definite rate of rotation of the prime mover, and to maintain the solution level in the tanks by means of an ordinary float valve. The use of such plates and valves will do away with the necessity of any hand regulation whatever except control of the speed of h the driving engine.

The orifice plates 18 and 18 are diagramwhich 3434 are pipe flanges, 35 is a hard metal plate having an opening or orifice 37 of predetermined area, and 36--36 are bolts for retaining the plate between the flanges. This water into said tanks in predetermined proportion; pumping means for separately and continuously withdrawing said solutions from said tanks and for separately forcing said solutions to a point of intermixture thereof, and means or proportioning the quantities of said solutions delivered by said pumping means, each said proportlonlng means comprising a bypass communicating between the discharge side and the suction comprising:

side of said pumping means, a release valve in said bypass for maintaining a predetermined pressure on said discharge side, and an orifice in said discharge between said pump and said point of intermixture for discharging a predetermined flow of liquid at said predetermined pressure.

2. An apparatus for continuously and simultaneously roducing dissimilar solutions of foam pro ucing chemicals, comprising: tanks for maintaining separate bodies of solution of said chemicals; means for separately feeding said chemicals in the form of dry powders into said tanks; means for agitatmg the contents of said tanks to facilitate solution of said powders; means for admitting water into said tanks to maintain a predetermined liquid level therein; pumping means for separately and continuously drawing streams of said solutions from said tanks and for separately forcing said streams to a point of intermixture thereof, and means or proportioning said streams, each said prosi e, and an orifice in said pump and said point of intermixture for discharging a predetermined fioW of liquid at said predetermined pressure.

In witness that I claim the foregoing I ave hereunto subscribed my name this 20th day of September,1927.

PAUL W. PRUTZMAN.

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