Abstract: A fire fighting fluid proportioning system and method including a fire fighting fluid conduit in fluid communication with a fire fighting fluid regulating valve and a venturi, the venturi in fluid communication with a valve source of fire fighting foam concentrate, and having a pilot valve connected directly or indirectly to the regulating valve and the concentrate source valve and adapted to adjust, directly or indirectly, the regulating valve and the source valve in response to a sensed indicia of fire fighting fluid pressure in the conduit.

Abstract: Foam for suppressing fires is formed by mixing together a constant stream of compressed air and water from a pump at a controlled rate with a quantity of a foaming agent from a foaming agent supply proportional to the rate of flow of water so as to be incorporated therein. An agitator mixes the water and the foaming agent into the stream of compressed air to generate the foam. The rate of flow of the water is controlled by a continuously variable valve member driven between five set positions by an electronically controlled motor including a fully open position, in which a maximum flow rate of the water is supplied to the mixer with the proportional quantity of a foaming agent, a fully closed position, in which the flow of water and the flow of a foaming agent from the foaming agent supply are halted, and at least three intermediate positions of different foam characteristics.

Abstract: An apparatus for creating a fine liquid mist includes a container capable of holding fluid; one of a perforated basket and a porous bag disposed in the container; a liquid supply connector connected to the container; a mixing chamber connected to the container; and at least one convergent/divergent nozzle connected to the mixing chamber. A method of forming an effervescent fine liquid mist includes mixing liquid and chemical reactant to form non-toxic, noncombustible gas bubbles; mixing the liquid and the gas bubbles to form a two-phase fluid flow; and directing the two-phase fluid flow through at least one convergent/divergent nozzle.

Abstract: A NoFoam system which permits the testing of the Aircraft Rescue and Fire Fighting vehicle's foam delivery system. The NoFoam system includes the piping, valves, and connecting elements to interface with the fire vehicle's foam delivery system, while minimizing the release of Aqueous Film Forming Foam (AFFF) to the environment.

Abstract: A fire extinguishing installation comprising a liquid container (3), a gas container (1), and a feed line (4) to at least one spray head (5), the gas container being connected at a connection point (K) via a second line (6) to the feed line, and a valve (9) connected to the outlet (U) of the liquid container and to the feed line. In order for the fire extinguishing installation to be suitable particularly for extinguishing liquid fires without it causing splashing of the burning liquid, the valve (9) comprises a liquid space (10), connected to the feed line (4), a gas space (12), connected to the second line (6), and a spindle (13) arranged between the liquid space (10) and the gas space (12), which spindle either prevents or enables communication between an outlet (U) of the liquid container (3) and the liquid space (10).

Abstract: The purpose of the invention is to protect an instrumented firefighter's fire hose nozzle from shock and undesirable environmental pollutant penetration. The invention provides for doing this through the use of a rugged cover on the equipment as well as soft equipment mounts. The cover provides the instrumentation with protection from impact as well as protection from contamination by environmental pollutants. On the inside of the cover, the shock sensitive equipment is seated on an island that is mounted by one or more soft vertical posts, which protect this equipment from shock.

Abstract: An apparatus for introducing liquid and/or inert gas into a liquid extinguishing medium, including an extinguishing line having at least one extinguishing nozzle; an extinguishant supply line, having a non-return valve, which provides extinguishant to the extinguishing line; a supply tube, having a metering valve, which provides liquid and/or inert gas to the extinguishing line; and a perforated distributor body, within the extinguishing line, having at least one hole arranged along the distributor body and between two sequentially extinguishing nozzles.

Abstract: A reservoir of super absorbent polymers which can be independently pressurized, remotely stored and a supply of water which is admixed with the SAP at a point closely adjacent of an adjustable nozzle. In one embodiment the system involves a home unit with a portable hand carried reservoir which can be pressurized. Yet another system involves a back pack carried by a homeowner or firefighter for spraying which can be pressurized. Yet another embodiment involves a reservoir which can be independently pressurized with a pump so that any reduction in the water pressure in a tap line can be overcome by the SAP auxiliary pressure delivery. Other embodiments relate to a portable unit containing both the water reservoir and the SAP reservoir to the end that it is self-contained, and the admixing can be a function of wherever the homeowner, firefighter or rescue person should don the equipment.

Abstract: In a portable foam fire extinguisher with pressurized foam stabilization, including a container for the fire extinguishing medium, a pressurized gas bottle in communication with the container and a fire extinguisher gun connected to the container by a hose for supplying the fire extinguishing medium to the fire extinguisher gun, a mixing device is connected, by way of a pressure hose, to the pressurized gas bottle for admixing pressurized gas to the flow of the fire extinguishing medium to the fire extinguisher gun to provide therein pressurized gas bubbles, which expand when the mixture is discharged from the gun thereby accelerating the flow from the gun while forming a foam which adheres to the surfaces covered thereby.

Abstract: The present invention provides new compressed air foam systems for use as firefighting equipment. One compressed air foam system has a water inlet connected to a water flow path through the compressed air foam system. A water and foam chemical mixer is flow connected to the water inlet and has a foam chemical inlet and a water/foam chemical outlet. An air compressor is provided which has an air inlet, an air outlet, and an air flow controller at the air inlet. A foam mixer is flow connected to the water/foam chemical outlet of the water and foam chemical mixer and to the air outlet of the air compressor. The foam mixer has a foam outlet which provides firefighting foam to a fireman's hose for application to a fire. A control system has a sensor in sensing relationship with the water flow path through the compressed air foam system for sensing water flow.

Abstract: A process and a device for atomization of a liquid extinguishing medium, in which the liquid extinguishing medium and a liquid inert gas are mixed in a mixing unit to form a liquid extinguishing medium mixture. The mixture is conveyed through a conduit to a distributing device such as extinguishing nozzles. As the mixture exits the distributing device the mixture is atomized, forming an aerosol spray for extinguishing a fire within an extinguishing area defined by the aerosol spray. A detector arranged in the extinguishing area for detection of parameters relating to extinguishing of the fire is connected to an evaluation device which in turn is connected to a control valve. The control valve regulates the quantity of liquid inert gas supplied to the mixing unit.

Abstract: A drive source for feeding extinguishing medium into at least one spray head (2, 3) for extinguishing fire has a liquid source (5) and a gas source (9), apparatus for mixing the liquid and gas from their sources (5,9) and apparatus for transporting the mixed liquid and gas to the spray head (2, 3). In order for the drive source to control dosage of the gas into the liquid and, preferably, substantially even and small droplet size for a substantially long time during the extinguishing, the apparatus for mixing the liquid and gas has a piston-and-cylinder apparatus (50) including a first piston (12) in a first cylinder (10) and a second piston (13) in a second cylinder (11) for providing simultaneously at each stroke both liquid and gas to the apparatus or transporting the mixed liquid and gas.

Abstract: Apparatus and method for in-line inducting additive into a fire fighting flow line before the pump, including automatic regulating of water flow.

Abstract: A main tank of a foamable soap and water mixture is fluidly connected to a manifold positioned on top of the tank. A pair of air tanks are fluidly connected to the manifold as well and are also mounted on the tank. Within the manifold the foamable fluid of the tank and the gas of the air tanks is mixed in a manner such that the gas is parallel to the flow of the fluid through the manifold thereby precluding a damming effect of the fluid by the air. This foams the foamable fluid which is then passed to a conventional fire hose for dispersement therethrough.

Abstract: A portable fire suppression system which uses cold compressed air foam to extinguish fires. A solution suitable for generating foam is mixed with air in an expansion manifold where the foam is supercharged and expands up to 40 times original volume. The foam is discharged out a nozzle controlled by a charge valve which controls flow rate and moisture content of the foam. The fire suppression system is mounted on a compact sturdy frame capable of withstanding parachute drops to remote sites, and includes a frame with a hitch and wheels for ground mobility.

Abstract: A firefighting training apparatus is provided for simulating the pumping of water through various long lengths of hose to train firefighters to deliver a proper amount of water through the fire hose. The apparatus includes a disk having one or more apertures therethrough. The one or more apertures permit the passage of water through the disk while providing resistance to the water to simulate the resistance encounted by water flowing through a long length of fire hose. The firefighting training apparatus is used by placing the disk within the flow of water through the fire hose. A firefighter can practice delivering a proper amount of water through a fire hose to a nozzle without the need of using a long length of fire hose.

Abstract: A proportional fluid injector apparatus utilizing foaming agents. A pump is connected to a foaming agent and is operably connected to a differential proportional valve having a venturi. A first diaphragm control valve is operably connected between the pump and the venturi. A second diaphragm control valve is operably connected between the downstream and upstream sides of the pump and is also connected to a pilot line connected upstream of the venturi. The spring pressure exerted on the diaphragm in the first control valve is such that excess fluid from the pump returns upstream of the pump when the downstream pressure in the pump exceeds a predetermined value.

Abstract: A device for introducing CO.sub.2 into a preferably liquid extinguishing medium includes a housing (1) with a feed line (2) for extinguishing fluid, a feed pipe (4), provided with a metering valve (3), for CO.sub.2, as well as an outlet line (5). The housing (1) is aligned with its longitudinal axis vertical; the feed line (2) for extinguishing fluid is connected to the housing at the lower end thereof; the outlet line (5) branches off from the upper end of the housing. The CO.sub.2 feed pipe (4) opens into the housing from above, extends as far as the lower end thereof and is provided at the pipe end with injection fluid (6). The CO.sub.2 is directed in the feed pipe in the opposite flow direction to the extinguishing fluid; the length of the feed pipe between the metering valve (3) and injection fluid (6) is dimensioned such that during operation with the metering valve (3) closed a gas cushion (7) forms on its downstream side.

Abstract: A vehicle for fighting fires in remote areas comprises an all terrain vehicle carrying a water-fillable tank, a water pump in fluid communication with the inside of the tank, an engine to operate the pump, and at least one hose for directing the pumped water, preferably foamed with a foaming agent at the fire.

Abstract: A foam pump system for injecting chemical foamant into a firefighting stream includes a water pump, a foam pump, and an optional air compressor which are all connected to a common transmission. The transmission includes an input shaft which may be connected to a single power source (such as an engine of a fire truck) for driving the water pump, foam pump, and air compressor. The water pump, foam pump, and air compressor are preferably mounted (directly or indirectly) on the transmission to provide a compact unit that may be sold in modular form for ready incorporation into a firefighting apparatus such as a fire truck. The system also advantageously includes a hydrostatic transmission for selectively and accurately driving and controlling the speed of the foam pump and the resultant proportion of chemical foamant that is injected into the fire fighting stream.

Abstract: A fire extinguishing system having a high pressure liquid accumulator unit (1') and a pump unit (2'). The high pressure liquid accumulator unit has at least one liquid bottle (4a', 4b') for extinguishing liquid, the liquid bottle being connected to a gas source (6a', 6b') through a gas supply line (5') and having an inlet aperture for reception of gas from the gas source. The pump unit has a pump (10') and drive (11') for driving the pump. A line (15') for feeding extinguishing liquid extends from the liquid bottle in order to provide spray heads (3) with extinguishing liquid and the pump is connected to the liquid bottle through a supply line (12') in order to provide the liquid bottle with liquid. In order to enable an effective and, as to the time, relatively long delivery of extinguishing liquid at high pressure with an essentially decreased risk of ice formation, the supply line (12') of the pump is connected to the gas supply line (5') of the gas source by a connecting space (13a', 13b').

Abstract: A balanced pressure proportioning system for injecting firefighting foam concentrate into a stream of water is provided. The system includes a primary conduit having a central and a spring-biased piston disposed immediately downstream of the restriction. Foam is supplied to the conduit from a chamber which is in communication with the conduit through a foam passageway at a point disposed immediately downstream of the restriction. The chamber is divided into a foam section and into a water section by a diaphragm or other suitable member. The water section of the chamber is maintained at the upstream water pressure by way of a water passageway which provides communication between the water section and the conduit at a point disposed upstream of the restriction. Pressure is communicated from the water section of the chamber to the foam section of the chamber by the diaphragm or other suitable movable member.

Abstract: An additive supply mechanism and method for fire fighting mechanisms, such as fire fighting trucks, including an additive supply conduit, an additive pump means, a recirculation line having a balanced pressure valve throttling the line, at least one sensor measuring recirculation line flow and an additive pump output control apparatus responsive to measured recirculation line flow.

Abstract: An improved additive eductor for supplying additives, including foam concentrates and thixotropic foam concentrates, into a hand line or waterline for supplying a nozzle used for fire fighting operations wherein the additive eductor can be operated in either eductive or non-eductive by-pass mode and further comprising in a prefered embodiment a back-flow preventative metering valve attached to a additive port.

Abstract: A nozzle apparatus for delivering a fire-retardant foam including a fluid delivery member having an interior passage of a given diameter, an expansion tube connected to the fluid delivery member, an agitator positioned within an interior passageway of the expansion tube and an aspiration port formed in the expansion tube. The interior passage of the fluid delivery member extends to a tapered region having a outlet orifice at a narrow end of the tapered region. The interior passage is connected to a wide end of the tapered region. The aspirator port is positioned between the outlet orifice and the agitator. The expansion tube has an interior passageway extending to an outlet opening opposite the fluid delivery member. The outlet orifice opens to the interior passageway of the expansion tube. The interior passageway has a greater diameter than a diameter of the outlet orifice. The agitator is positioned within the expansion tube so as to turbulently mix the solution with air within the interior passageway.

Abstract: A portable fire suppression system which uses cold compressed air foam to extinguish fires. A solution suitable for generating foam is mixed with air in an expansion manifold where the foam is supercharged and expands up to 40 times original volume. The foam is discharged out a nozzle controlled by a charge valve which controls flow rate and moisture content of the foam. The fire suppression system is mounted on a compact sturdy frame capable of withstanding parachute drops to remote sites, and includes a frame with a hitch and wheels for ground mobility.

Abstract: A test system for use in testing Aircraft Rescue Fire Fighting and Structl Pumper vehicles equipped with fire fighting foam distribution systems. The dye piping arrangement for the test system uses a dye concentrate and water mixture which are delivered into the dye water foam free test system through a three way ball valve, a proportioner and eductor. Fluid flow through the eductor generates a vacuum or negative pressure within the eductor. The dye concentrate from a dye storage bottle is then suctioned into the foam distribution system by the negative pressure within the eductor. A needle valve, check valve and a dye solenoid valve are included in the system. The needle valve meters the amount of dye suctioned into the dye water foam distribution system. The check valve prevents any fluids from back flowing into the dye concentrate tank. The normally closed dye solenoid valve is remotely operated by an ON-POWER OFF-OFF three position switch.

Abstract: A portable fire fighting and vapor suppression apparatus includes a cart having sides defining an enclosure and is a size so that it can be manually moved by a single individual. The cart includes a bottom having wheels mounted thereon. The cart has an internal partition forming an enclosed storage area that is separate from the rest of the enclosure which forms a sealed holding tank for storing a foam concentrate. An eductor is mounted within the enclosed storage area and has an inlet for connecting to a source of high pressure water. The foam eductor includes a foam mixing portion and a discharge. A foam pickup tube is connected to the foam mixing portion and extends through the internal partition to the form holding tank for sucking foam concentrate as water is forced through the inlet and eductor.

Abstract: A foam nozzle for fighting fires is disclosed. The nozzle has an over-all conical shape, with a plurality of air holes and a plurality of agitation screens. The nozzle is simply slipped over the end of the traditional non-foam nozzle and held in place with a thumb screw or similar device.

Abstract: An additive supply system for fire fighting mechanisms such as a fire fighting truck including an additive supply line system having a pump and a recirculation line, a balanced pressure valve metering flow in the recirculation line and in communication with the measure of additive line pressure and fire fighting fluid line pressure, and additive pump control apparatus connected to the additive pump and in communication with the measure of the degree of openness of the balanced pressure valve.

Abstract: A combination carrying handle and control valve for firefighting apparatus suspends a portable reservoir. A handle is formed by a tubular wall having an inlet end and an outlet end and forming a flow passage between the ends; and a coupling is fastened to the inlet end and another coupling is fastened to the outlet end for connecting the handle to a source of liquid under pressure and to an accessory, respectively. A manually operated flow control valve is mounted in the handle for controlling the flow of liquid. The handle is part of a tank that may contain a liquid additive, and an eductor is connected between the flow passage and the tank interior for drawing the additive from the tank.

Abstract: Fire-fighting equipment has a hydraulic accumulator which contains fire-fighting liquid and a space for a pressure gas, a source of the pressure gas, a connection for connecting the pressure gas of the source to the hydraulic accumulator, and an outgoing tube from the hydraulic accumulator for discharging the fire-fighting liquid from the hydraulic accumulator for fire-fighting use. A gas inlet in the hydraulic accumulator receives the pressure gas from the connection. The tube supplies a portion of the pressure gas to the space for the pressure gas in the hydraulic accumulator. A rising tube in the hydraulic accumulator supplies the fire-fighting liquid from the hydraulic accumulator to the outgoing tube when the pressure gas is supplied to the space for the pressure gas in the hydraulic accumulator. A throttle connected to the connection mixes another portion of the pressure gas into the fire-fighting liquid supplied to the outgoing tube.

Abstract: A fire extinction device uses water which is driven by compressed air. Upon passing the water through a dosing apparatus, where the water is mixed with a foaming liquid, the air foam is generated and then expelled through a foam spout. The device includes, among other elements, an air compressor, a first tank containing the water, a second tank containing the foaming liquid, and a fire hose through which the water and foaming liquid mixture passes.

Abstract: An apparatus for continuous production of finished foam material, in which the proportions of the constituents are monitored and continuously adjustable during operation of the machine. The liquid components are metered by positive-displacement, progressive-cavity, screw-type pumps driven by variable speed motors. Rates of flow are monitored by flow meters, and the relative proportions of the constituents can be closely adjusted by varying the speeds of the pump drive motors and observing the flow meter readouts. The finished foam produced by the apparatus may be used, for example, for the preparation of foamed cement grouts or for fighting fires.

Abstract: A fire fighting system has a liquid source, a pump connected to the liquid source having an outlet line with spray heads for providing a high liquid pressure and a comparatively small flow, and a gas source of propellant gas connected by way of a line to the outlet line for mixing gas with the liquid into a flow of an extinguishing fluid delivered to the spray heads. The gas source is connected to the outlet line of the pump for producing a finely divided liquid mist, an initial charge pressure of the gas source being at least as high as the high liquid pressure provided by the pump. At least one liquid tank is between the gas source and the outlet line.

Abstract: The invention relates to a method of extinguishing fires in closed or open spaces using water and foam. The method is characterized in that water mist is first produced with the air available in the space without air supply from outside until the temperature in the combustion gases has fallen below a predetermined level or during a predetermined period of time, whereupon foam is produced with the air available in the space without air supply from outside and with a suitable speed for filling the space and extinguishing the fire. The invention also includes a means for performing the method comprising units for producing water mist and foam in the space and a closing or controlling valve (33) which, in dependence upon the temperature in the combustion gases or period of time elapsed from the start of the water mist production, controls the amount of foam liquid added to the water.

Abstract: A nozzle assembly including a nozzle body having an inlet at a first end and an outlet at a second end. A first fluid passageway is defined within the nozzle body for first fluids passing between the inlet and outlet. Second and third fluid passageways for respective second and third fluids are also defined within said nozzle body. A discharge mixing unit is provided at the second end and is in fluid communication with the first, second and third fluid passageways for mixing the first, second and third fluids to produce a discharge solution. The discharge mixing unit includes one or more mixing chambers provided on the interior surface of the second end of the nozzle body. The mixing chambers are defined between a plurality of inwardly extending blades from the interior surface of the second end. The second end of the nozzle body has an adjustably extending pattern selection sleeve.

Abstract: Plural liquid streams supplied to a foam tube of a nozzle include an outer hollow cylindrical stream surrounding a plurality of spaced-apart inner streams for enhancing mixture of air and liquid in the foam tube.

Abstract: A microprocessor-based dual tank control system for use in a foam-injection fire fighting system which automatically proportions the selected foamant into the main water stream at a predetermined concentration, automatically provides an accurate assessment of the amount of foam pumped out of the selected supply tank, and automatically flushes the injection line at system power-up and between flow cycles.

Abstract: A helicopter (20) is equipped with a foam generating device (22) comprising a tank (1) associated with a pump system (2) and a mixer device (36) to deliver a mixture water-emulsifier. A spraying system (44) comprises two modules (44a, 44b) arranged on the side faces outside the helicopter (20), each module comprising a frame (3) mounted pivotally around and axis (6) between an upward inactive position and a lowered active position, and a network (4) linked with the exhaust pipe of the mixer device (36). The network (4) is placed under the blades (46) of the helicopter (20), and is constituted by a pattern of squares equipped with a multitude of sprinklers (5) which can spray the mixture water-emulsifier over the tight-mesh net (11) to produce foam under the action of the pressurized air generated by the blades (46). The moving of the modules (44a, 44b) between the two lifted and lowered positions is ensured by a lifting device (9) with hydraulic or electric control.

Abstract: A fire control foam distribution system wherein foam is distributed to the area below a passenger boarding bridge includes a telescoping pipe system to get the foam to delivery manifolds at intermediate and at an outboard location of the passenger boarding bridge. Multiple foam delivery discharge nozzles are attached to the delivery manifolds to assist in directing the foam to the area below the passenger boarding bridge.

Abstract: A low pressure, self-contained fire suppression system comprising a source of pressurized gas, a water reservoir tank containing water, a foam concentrate tank containing foam concentrate, and a water driven volumetric metering pump. The source of gas under pressure communicates with the water reservoir tank to provide a source of water under pressure. A conduit communicates the pressurized water tank with a first inlet port of the metering pump. The foam concentrate tank communicates with the metering pump via a second inlet port. Concentrate is supplied to the metering pump at a predetermined volumetric flow rate in response to water flowing through the metering pump. The source of pressurized gas also communicates via a conduit with the outlet port of said metering pump to thereby introduce gas under pressure to the water/foam concentrate mixture as it exits the metering pump. The water, foam concentrate and gas mixture is passed through a conduit, such as a hose, wherein a foam is generated.

Abstract: The fire suppressant foam generation and application apparatus 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 stata tube apparatus to agitate the foam/water mixture to create the fire suppressant foam. A pressurized gas operated pump can be used to actively draw the water/foam mixture from a supply tank and supply it under pressure to the stata tube and outlet line. This apparatus can be implemented as a backpack unit consisting of a storage tank, formed as a substantially U-shaped molded element, which contains the liquid foam concentrate/water mixture. A high pressure tank containing pressurized gas, either nitrogen or a nitrogen-air mixture, or other suitable gas mixture, is included in an aperture formed in the storage tank housing.

Abstract: An apparatus for generating foam includes a power source such as an internal combustion engine mounted in a frame for portable transportation of the apparatus. The power source drives an air compressor through an electric clutch which can disconnect the air compressor and a water pump. The water pump generates flow of the water under pressure through a duct system either to a water discharge valve or to a foam discharge valve. The foam is generated by injecting into the water stream a surfactant which is injected by reciprocating valve arrangement operated by flow of the water. The flow is controlled by a maximum flow orifice, a minimum flow orifice and an adjustable valve. The air compressor supplies a surge tank and the air is passed from the surge tank through a pressure regulator to a mixing device where the water and surfactant is mixed with the air to generate the foam.

Abstract: Mechanical foam fire fighting equipment and method wherein an inert gas is delivered to a foaming chamber of a mechanical foam making assembly, the foaming chamber also receiving a liquid and foam concentrate, the inert gas in some embodiments being supplied by the exhaust of an engine.

Abstract: The performance and throw distance of a nozzle discharging a water stream is enhanced by injecting a liquified gas, suitably liquid nitrogen or liquid carbon dioxide, into the water entering the nozzle at a point sufficently upstream from the nozzle to allow complete vaporization or solidification of the liquified gas before it leaves the nozzle. A second material, that may be a foam producing composition or a particulate solid, may be introduced into the water entering the nozzle simultaneously with the introduction of the liquified gas.

Abstract: Fires in tanks storing combustible liquids are extinguished using water from a settled layer at the tank bottom to form a foam that is transported to the top of the combustible liquid by the lifting action of an inert gas stream introduced into the tank at a location below the liquid surface. A stream of water is removed from the tank, mixed with a foam-forming concentrate, merged with a flowing stream of inert gas, and circulated back to the tank at a point below the surface of the stored liquid to form an upwelling foam column which explodes upon the liquid surface and spreads across that surface to extinguish the fire and prevent its reignition.

Abstract: A foam generating apparatus can be attached to a water bearing hose and comprises an eductor nozzle to receive water and foam concentrate, and a foam generating nozzle to discharge a foam/water mixture therethrough. A foam concentrate conduit delivers concentrate to the eductor nozzle and has a concentrate valve to control flow therethrough, e.g. a one-way check valve to prevent water from passing outwardly through the foam concentrate conduit to dilute the concentrate. A delivery manifold communicates the foam concentrate conduit with a suction port of the eductor nozzle and extends peripherally around the suction port to permit foam concentrate to be drawn into the eductor nozzle for discharge therethrough. The foam generating nozzle receives the foam/water mixture and has air entrainment openings to admit air into the mixture and an agitator jet orifice for agitating the mixture located generally adjacent the air entrainment openings.

Abstract: A fire-fighting system in which a liquid chemical foamant is introduced into the water stream in varying amounts so as to maintain a predetermined percentage mixture irrespective of variations in the water flow includes a motor-driven pump where the motor is controlled over a first speed range by pulse width modulating the drive to the motor and over a second speed range, producing intermittent motion, by burst width modulating the drive signal when it is operating at its minimum pulse width modulated duty cycle. Using this technique the range of available motor speeds is extended well beyond that which can be achieved using pulse width modulation of the motor drive signal alone.

Abstract: A system for supplying compressed air and foam to produce a fire stream comprising an aerated foam is disclosed. The system includes an air compressor driven from a split shaft gear box of the type provided on fire trucks.