GB2031724A

GB2031724A - Foam generating fire fighting device

Info

Publication number: GB2031724A
Application number: GB7928155A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-08-14
Filing date: 1979-08-13
Publication date: 1980-04-30
Also published as: GB2031724B; AU530865B2; AU4979079A; CA1119565A

Abstract

This invention is concerned with a method of, and apparatus for, generating and discharging foam for fire-fighting purposes. The apparatus includes a container for receiving and storing a foam generating solution, ejector means for discharging the solution to a discharge tube, foam generating means, and pressure generating means which communicate with a chamber for aerating the foam generating solution prior to discharging the solution. <IMAGE>

Description

SPECIFICATION Foam generating fire fighting device TECHNICAL FIELD This invention relates to fire fighting equipment, and more particularly to a fire fighting foam generating device for introducing air into a foam generating solution.

BACKGROUND ART In the past several years fire fighting techniques have included the use of applying a saponaceous or surfactant solution to burning material. These solutions are saturaed with air to produce an abundance of bubbles turning the solution into a voluminous froth to smother the burning material and extinguish the fire. Typical foam generating devices are described and claimed in U.S. Patent Nos.

1,753,429 issued to Rice on April 8, 1930 and entitled "Apparatus for Producing Foam" and 2,908,334 issued to Duggan, et al on October 13, 1 959 and entitled "Process and Apparatus for Generating and Discharging Foam".

Such prior art foam generating devices have used specially designed complex and expensive nozzles for the introduction of air into the foaming agent and for agitating the air-foaming agent mixture to produce foam at the nozzle head. This technique requires a large amount of pressure to pump the foaming agent through the nozzle in addition to specially designed nozzles. Additionally, prior art foam generating devices include complex mechanical systems making them difficult to maneuver when fighting a fire and which are difficult and costly to maintain.

A need has thus arisen for a foam generating device that is simple in operation and is operable with a minimum amount of pressure to pump the foaming agent. Additionally, a need has arisen for a foam generating device in which the aeration and agitation of the foam generating solution are accomplished without the need of specially designed nozzles.

DISCLOSURE OF THE INVENTION In accordance with the present invention, a foam generating device for aerating and agitating a foam generating solution is provided.

In accordance with the present invention, a foam generating device is provided for generating and discharging foam. The device includes a container for receiving and storing a foam generating solution. A discharge tube is connected to the container, and an ejector tube is disposed within the container for discharging the foam generating solution to the discharge tube. Foam generating structure is disposed between the ejector tube and the discharge tube exterior of the container and includes a chamber communicating with the ejector tube for permitting the passage of the foam generating solution therethrough to the discharge tube. A pressure generator communicates with the container for forcing the foam generating solution through the ejector tube and the foam generating structure. The pressure generator further communicates with the chamber for aerating the foam generating solution.

In accordance with another aspect of the present invention, an apparatus for generating and discharging fire extinguishing foam includes a container for receiving and storing a foam generating solution. A discharge tube is connected to the container, and an ejector tube is disposed within the container for discharging the foam generating solution to the discharge tube. An aeration chamber is provided and includes a plurality of apertures.

The aeration chamber is disposed between the ejector tube and the discharge tube exterior of the container and is operable to permit the passage of the foam generating solution therethrough. A source of propellant is provided for introducing a propellant into the container for forcing the foam generating solution through the ejector tube and the aeration chamber.

The propellant communicates with the aeration chamber apertures for introducing air into the flow of the foam generating solution to generate foam within the discharge tube.

In accordance with yet another aspect of the present invention, a method for producing foam from a foam generating solution includes the step of storing a foam generating solution in a container. A propellant is passed through the container to force the foam generating solution into a foam generating chamber. The foam is generated by aerating the foam generating solution within the chamber by passing a propellant through the chamber.

The aerated foam is agitated within a foam discharge tube. The propellant further discharges the agitated foam from the discharge tube.

BRIEF DESCRIPTION OF DRAWINGS A more complete understanding of the invention and its advantages will be apparent from the following Detailed Description taken in conjunction with the accompanying Drawings in which: Figure 1 is a side elevational view, partially in section, of the foam generating fire fighting device of the present invention; and Figure 2 is a sectional view taken in the same plane of Fig. 1 of the foam generating structure of the present foam generating fire fighting device.

DETAILED DESCRIPTION Fig. 1 illustrates the present foam generating fire fighting device and is generally identified by the numeral 1 0. Foam generating device 10 includes a tank 1 2 leak tightly sealed at either end to an upper header 14 constructed of materials impervious to or protected from the foam generating solution stored therein. The lower end of tank 1 2 includes a base 1 8. Tank 1 2 includes a foam generating solution 24 filled to a level indicated at 26. Foam generating solution 24 for use in the present foam generating device 10, is selected depending upon the type of fire to be extinguished.

Connected to header 1 4 is a fitting 30 for receiving and interconnecting an ejector tube 32 and foam generating assembly, generally identified by the numeral 34, to tank 1 2.

Ejector tube 32 includes a weight 36 for maintaining ejector tube 32 centrally disposed within tank 12. Upper header 14 also includes a port 28 for filling and draining foam generating solution 24 from tank 1 2.

Foam generating assembly 34 includes a connector 38 interconnected to fitting 30. Tconnector 38 receives fittings 40, 42 and 44.

Fitting 40 is interconnected to a hose 50. As shown in Fig. 1, hose 50 is interconnected to a pressure tank 52 through a regulator 54 and a valve assembly 56 to pressurize tank 1 2. Pressure tank 52 may contain, for example, nitrogen, carbon dioxide, halogen, freon, compressed air or mixtures thereof for maintaining foam generating solution 24 under constant pressure within tank 1 2. Alternatively, conventional water pump lines such as supplied from fire fighting tank trucks can be interconnected to hose 50 for pressurizing tank 12.

Fitting 42 of T-connector 38 is interconnected to a pressure release valve 60. Fitting 44 is interconnected to an elbow section 62 that receives a fitting 64, valve 68 and a nozzle 70. Control valve 67 and nozzle 70 are conventional devices well-known to those skilled in the art.

Referring simultaneously to Figs. 1 and 2 wherein like numerals are utilized for like and corresponding elements, it can be seen that Tconnector 38 joins fittings 30, 40, 42 and 44 and defines a cavity 72. Disposed within cavity 72 and interconnecting fittings 30 and 44 is an aeration chamber, generally identified by the numeral 74. Aeration chamber 74 includes a stem portion 78 for insertion through fitting 30 for frictionally receiving ejector tube 32. Aeration chamber 74 further includes a threaded portion 80 for interconnecting aeration chamber 74 to fitting 44. An important aspect of the present invention are apertures 82 disposed circumferentially and centrally around aeration chamber 74.Apertures 82 function to introduce propellant or air into the flow of foam generating solution 24 between tank 1 2 and discharge hose 66 to aerate foam generating solution 24 to thereby produce foam.

In operation of the present foam generating fire fighting device 10, propellant in the form of compressed air or compressed gas enters cavity 72 from a pressure source indicated by flow directional arrow 90. The propellant then flows through passage ways 92 defined between fitting 30 and stem portion 78 of aeration chamber 74. The flow of propellant in tank 1 2 is indicated by flow directional arrows 94. As a result of propellant entering tank 12, an increase in pressure is experienced by the foam generating solution 24 within tank 1 2 such that the foam generating solution 24 is forced into ejector tube 32 as indicated by flow directional arrow 96. Foam generating solution 24 therefore flows through ejector tube 32, through stem portion 78 and threaded portion 80 of aeration chamber 74, through fitting 44 to discharge tube 66.

Propellant from pressure tank 52 also flows through apertures 82 of aeration chamber 74 indicated by directional arrow 98. Propellant, introduced through apertures 82 into the flow stream of foam generating solution 24 passing from tank 1 2 to discharge tube 66, generates a foam-air or gas slurry 100 present in elbow 62 and indicated by flow directional arrow 102. The foam-air slurry 100 then passes through fitting 64 into discharge tube 66. The foam-air slurry 100 is then highly agitated by the turbulence and back pressure created within discharge tube 66 to form foam 104 for discharge through nozzle 70 (Fig. 1). The size of discharge tube 66 can be selected to obtain foam of desired volume and fluidity.

It therefore can be seen that a single source of propellant is utilized for forcing foam generating solution 24 from tank 1 2 and also for aerating foam generating solution 24 to produce foam 104. Foam generating solution 24 passing through aeration chamber 74 is thoroughly aerated due to the apertures 82 that permit communication between a propellant and foam generating solution 24. The number and size of apertures 82 is dependent upon the expansion factor desired for the generated foam as determined by the particular foam application.

While the present foam generating fire fighting device has been illustrated and described as being portable, additionally, the device can be permanently affixed to mobile vehicles, such as fire fighting trucks. Foam generating assembly 34 can be interconnected for in-line operation using a conventional fire hose supplied by a fire fighting truck pumping system including a foam solution. Fittings 30 and 44 would be interconnected directly into the fire hose and fitting 42 would be closed for in-iine operation. The system can also be utilized in a fixed system to protect buildings and stationary further modifications are possible without departing from the scope of the invention.

Claims

1. An apparatus for generating and discharging foam comprising; a container for receiving and storing a foam generating solution; a discharge tube connected to said container; ejector means disposed within said container for discharging said foam generating solution to said discharge tube; foam generating means disposed between said ejector means and said discharge tube exterior of said container and including a chamber communicating with said ejector means for permitting passage of said foam generating solution therethrough to said discharge tube; and pressure generating means communicating with said container for forcing said foam generating solution through said ejector means and said foam generating means, said pressure generating means further communicating with said chamber for aerating said foam generating solution prior to flowing to said discharge tube wherein said discharge tube further agitates and aerates said foam generating solution to thereby generate foam.

2. The apparatus for generating and discharging foam of Claim 1 wherein said pressure generating means includes a propellant communicating with said chamber and said container.

3. The apparatus for generating and discharging foam of Claim 2 wherein said chamber includes a plurality of apertures for introducing said propellant into the flow of said foam generating liquid flowing between said container and said discharge tube.

4. The apparatus for generating and discharging foam of Claim 3 and further including: fluid conduit means for channeling said propellant from said pressure generating means to said container and said chamber.

5. The apparatus for generating and discharging foam of Claim 3 wherein said propellant comprises compressed nitrogen.

6. The apparatus for generating and discharging foam of Claim 3 wherein said propellant is selected from the group consisting of compressed air, carbon dioxide, halogen, freon or mixture thereof.

7. An apparatus for generating and discharging foam comprising: a container for receiving and storing a foam generating solution; a discharge tube connected to said container; ejector means disposed within said container for discharging said foam generating solution to said discharge tube; foam generating means disposed between said ejector means and said discharge tube exterior of said container and including a chamber communicating with said ejector means for permitting passage of said foam generating solution therethrough to said discharge tube; pressure generating means communicating with said container for forcing said foam generating solution through said ejector means and said foam generating means, said pressure generating means further communicating with said chamber for aerating said foam generating solution prior to flowing to said discharge tube;; a propellant source including a propellant communicating with said chamber; and said chamber including a plurality of apertures for introducing said propellant into the flow of said foam generating solution, such that said chamber aerates said foam generating solution prior to flowing to said discharge tube wherein said discharge tube further agitates and aerates said foam generating solution to thereby generate foam.

8. The apparatus for generating and discharging foam of Claim 7 and further including: fluid conduit means for channeling said propellant from said propellant source to said container and said chamber.

9. The apparatus for generating and discharging foam of Claim 8 wherein said propellant comprises compressed nitrogen.

10. The apparatus for generating and discharging foam of Claim 8 wherein said propellant comprises compressed air.

11. An apparatus for generating and discharging fire extinguishing foam comprising: a pressurized container for receiving and storing a foam generating solution; a discharge tube connected to said container; an ejector tube disposed within said container for discharging under pressure said foam generating solution to said discharge tube; an aeration chamber having a plurality of apertures being disposed between said ejector tube and said discharge tube exterior of said pressurized container, said aeration chamber being operable to permit the passage of said foam generating solution therethrough; means for forcing said foam generating solution through said ejector tube and said aeration chamber; and said forcing means communicating with said aeration chamber apertures for introducing air into the flow of said foam generating solution to generate foam within said discharge tube.

1 2. The apparatus of Claim 11 wherein said means for forcing includes a pressurized propellant.

1 3. The apparatus of Claim 1 2 wherein said pressurized propellant comprises nitrogen.

14. The apparatus of Claim 1 2 wherein said pressurized propellant comprises air.

1 5. The apparatus of Claim 11 wherein said forcing means comprises pump means.

1 6. A method of producing foam from a foam generating solution comprising the steps of: storing a foam generating solution in a container; passing a propellant through the container to force the foam generating solution into a foam generating chamber; aerating said foam generating solution within said chamber by passing said propellant through said chamber; agitating said aerated foam within a foam discharge tube; and discharging said agitated foam from said discharge tube by action of said propellant.

1 7. The method of Claim 1 6 and further including pressurizing said propellant prior to permitting the passage thereof through said container.

18. The method of Claim 16 and further including: passing said propellant through apertures within said chamber for mixing said propellent with said foam generating solution prior to agitating said foam.

1 9. Apparatus for generating and discharging foam, substantially as hereinbefore described with reference to, or as shown in, the accompanying drawing.

20. A method of generating foam, substantially as hereinbefore described.