Patent Application
20130112773
This invention relates to a foam generation apparatus and, in particular, to an apparatus for generating and delivering foam using a compressed air-powered backpack form factor foam generator system.
There are a number of applications where there is a need to generate a foam-based product. These applications include, but are not limited to: fire fighting; hazardous materials remediation; cleaning/sanitization; and decontamination of apparatus, buildings, and people.
There is no practical, compact form factor, delivery system for foaming formulations for these types of applications. The process of decontaminating equipment and/or a site is typically effected using large size, fossil-fuel powered, power wash generators. The decontamination product that is delivered is typically a caustic, sometimes heated, liquid which is applied to the surface to be decontaminated. These units are bulky and the fluid that is delivered fails to adhere to the surfaces to which it is applied if the surfaces are vertically oriented.
It is also a problem in the field of fire fighting to provide a sufficient volume and quality of fire fighting material to suppress a fire. The traditional fire fighting material used for this purpose is water, which has the undesirable side effect of causing a significant amount of water damage to the real property in and around the area in which the fire is engaged. In fact, in many situations, the water damage to the real property is significantly in excess of the fire damage to the real property. An alternative fire fighting material in use is fire suppressant foam. However, the difficulty with fire suppressant foam is that the typical materials used for this purpose require complicated mixing and pumping apparatus and still produce a significant amount of water damage due to the relatively high water content of the foam.
In a typical application, the availability of a significant water supply renders water the desired choice as a fire fighting material, since the fire suppressant foam itself requires a significant amount of water. In addition, fire suppressant foam requires complicated generation and delivery apparatus, thereby rendering it impractical for use except in certain selected applications, such as airport fire fighting applications where the use of water is ineffective in controlling the magnitude and extent of a fuel fire.
One departure from the fire fighting prior art is taught by U.S. Pat. Nos. 5,623,995 and 6,155,351, which disclose a fire suppressant foam generation and application apparatus that produces a low-moisture-content fire suppressant foam for use in fire fighting applications. The reduction in the water content of the fire suppressant foam is accomplished by the use of pressurized gas in place of water along with a foam concentrate agitation apparatus to agitate the foam concentrate/water mixture to create a fire suppressant foam. A pressurized gas-operated pump can be used to actively draw the water/foam concentrate mixture from a supply tank and supply it under pressure to the foam concentrate agitation apparatus and outlet line. The apparatus is a molded tank that has a cut out for the placement of the cylinder that contains the pressurized gas. This apparatus has the disadvantages of cost, weight, and size limitations since the use of a rigid molded tank adds weight to the product and eliminates the option of custom sizing the volume of product that is stored therein.
In current and emerging foaming technologies, it is desirable to have the ability to store, mix, and apply binary formulations. In these applications, proportional, controlled, and accurate mixing of formulary binary components is crucial to effective application of the binary formulas in their stated mission roles and performance specifications.
The above-described problems are solved and a technical advance achieved in the field by the Compressed Air-Driven Foam Generation Apparatus in a Backpack Form Factor of the present invention (termed “foam generator system” herein). This apparatus makes use of a commercially available low-moisture-content foam mixture in conjunction with a novel foam generation and application apparatus to improve on the backpack concepts taught in the above-noted U.S. Pat. Nos. 5,623,995 and 6,155,351. This apparatus is simple in structure and operation and makes use of a pressurized gas to create the binary or unitary formula's fluid/foam mixture (or fluid/foam+additive mixture), propel it through the delivery apparatus, and power an auxiliary pump to increase the delivery pressure of the generated foam. This apparatus is lightweight in construction, simple in architecture, and can be disassembled into its component parts, folded, and stored in minimal space. The use of one or more bladders to hold the fluid/foam concentrate (and optional additives) enables the user to custom select the volume of material staged in the unit, load different formula ingredients in separate bladders, proportionally mix separate ingredients, and to remove and replace a bladder in the event maintenance is required or different pre-packaged formulas are needed for varied mission conditions. This design optimizes for low weight, flexibility, and low cost and multi-mission applications.
The foam generator apparatus disclosed herein includes a pair of collapsible bladders for storing a fluid/foam concentrate mixture either as a single unitary formula or as a binary formula with different ingredients (one of water and foam concentrate) in each bladder and an air bottle forming a source of pressurized gas. These elements are mounted on a chassis which has a pump mounted on the chassis, connected to the air bottle, and powered by the pressurized gas, for mixing binary formulas in a controlled, proportional method, and producing a flow of the fluid/foam concentrate mixture from the pair of collapsible bladders to an output port, wherein the chassis attaches to a backplate which includes two sides pivotally attached to the backplate and operable to form an enclosure around the pair of collapsible bladders. An air injection apparatus is connected to the output port of the pump to mix a controllable volume of pressurized gas into the fluid/foam concentrate mixture received from the pump to create a foam.
Foam is produced from a combination of a fluid and a foam concentrate (unitary or binary or other multiple component formulas) and a propellant which functions to both agitate the fluid/foam concentrate mixture to create the expanded foam and to deliver it through the application apparatus. The propellant of choice in this system is a compressed gas which produces a dry foam mixture. Furthermore, the use of the pressurized gas eliminates the need for a large complex pumping apparatus to pump an incompressible fluid, such as water, that has been used in the past to agitate and supply the foam mixture to the spray nozzles. A simple hydraulic or pressurized gas-operated pump can be used to actively draw the fluid/foam concentrate mixture, where the pump is capable of proportional mixing of bladder contents of either unitary or binary foam concentrate formulas, from a supply tank and supply it under pressure to the outlet of the pump where it is mixed with and agitated by the pressurized gas to create the resultant foam. It is typical for one bladder to store the fluid, such as water, and the other bladder to store a foam concentrate. Alternatively, the foam concentrate is pre-mixed with the water and stored in the system as the fluid/foam concentrate and other additives may be added to this fluid/foam concentrate mixture in order to further condition the foam or to use the foam as a carrier of the additive as it is applied to an object.
The pair of collapsible bladders 101, 102 and air bottle 103 are mounted on a chassis 400, as shown in
The pressurized air operates the air-operated diaphragm pump 401 (or pumps 401A, 401B) to create a flow of the fluid/foam concentrate mixture from the bladders 101, 102 to a fluid fitting 211 (provided with a relief valve 212) which is connected to fluid/air fitting 213. Pressurized air also is drawn from four-way fitting 204A (or five-way fitting 204B) and applied to air injector 214 which enables the user to regulate the volume of pressurized air injected into the flow of fluid/foam concentrate mixture at fluid/air fitting 213 thereby to cause the fluid/foam concentrate mixture to expand due to the injection of the pressurized air. The result of the expansion process is the creation of foam, which is output via fluid fitting 215 to fitting 216 and into spray wand 217, where the user can control the application of the generated foam to the desired surface.
These various valves, fittings, and pipes are routed among the air bottle 103, collapsible bladders 101, 102, pump 401, and delivery wand 127 elements as shown in
A backpack architecture is used to implement the foam generator; and the pack optionally can be provided with a pair of wheels 131, 132 to facilitate transportation and storage. In addition, an optional extensible handle 104 can be provided to facilitate rolling the foam generator system 100 on its wheels 131, 132. The minimization of weight and cost is achieved through the use of collapsible bladders 101, 102 to store the foam concentrate mixture and the use of a lightweight chassis 400 that uses two pivotally connected sides 111, 112 to enclose the collapsible bladders 101, 102. Pockets (not shown) optionally are formed on the interior facing surface of the two pivotally connected sides 111, 112. For balance purposes, the pump 401 is mounted on the bottom of the chassis 400.
The backplate 115 includes one or more straps 152, 153 with buckles attached thereto, which are used to secure the chassis 400 to the backplate 115 and also the air tank 103 in place in the recess 402 formed in the chassis 400. The collapsible bladders 101, 102 each include a fill port 121, 122 with a lid to seal the opening. The fill port 121, 122 in the collapsible bladder 101, 102 is accessible via an opening formed in the top of the pivotally connected side 111, 112.
The foam generator apparatus includes a pair of collapsible bladders for storing a unitary or binary foam concentrate mixture and an air bottle forming a source of pressurized gas. These elements are mounted on a chassis which has a pump, mounted on the chassis, connected to the air bottle, and powered by the pressurized gas, for producing a flow of the foam concentrate mixture from the pair of collapsible bladders to an output port, wherein the chassis includes two sides pivotally attached to a backplate and operable to form an enclosure around the pair of collapsible bladders.
