CA2661671A1 - Surfactant injector for compressed air foam system - Google Patents
Surfactant injector for compressed air foam system Download PDFInfo
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- CA2661671A1 CA2661671A1 CA 2661671 CA2661671A CA2661671A1 CA 2661671 A1 CA2661671 A1 CA 2661671A1 CA 2661671 CA2661671 CA 2661671 CA 2661671 A CA2661671 A CA 2661671A CA 2661671 A1 CA2661671 A1 CA 2661671A1
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Abstract
A portable unit for generating foam for fire suppression comprises a frame carrying a bottle of compressed gas which supplies power to drive the foam generation from a water supply and a surfactant supply which are mixed with the compressed gas. The surfactant or foaming agent is metered by a manually driven piston system.
Description
SURFACTANT INJECTOR FOR COMPRESSED AIR FOAM SYSTEM
The present invention relates to a surfactant injector for use with a compressed air foam system of the type used for the production of foam for the purpose of fire prevention and suppression.
BACKGROUND
For some time foaming agents have been used to increase the effectiveness of water in the prevention and suppression of fires. Systems have traditionally used foaming agents, commonly known as surfactants, mixed in holding tanks or introduced into the water stream by a variety of methods. More recently systems have been developed which also provide for the injection of compressed air into the water/surfactant mixture to provide an improved quality and volume of foam and which are typically referred to as compressed air foam systems or CAFS.
In a portable configuration of a compressed air foam system it is known to provide a holding tank for receiving a mixture of water and surFactant therein from which a flow is generated. Compressed air is then injected into the flow of solution from the holding tank. In a small portable system, it is desirable for batch mixing of the surfactant and water in the holding tank which typically requires careful measuring of the surfactant prior to placement in the tank with water. Such measurement is typically required to be done manually such that messy measuring equipment must also be transported with the system. Furthermore such manual measurement can be time consuming and inaccurate.
The present invention relates to a surfactant injector for use with a compressed air foam system of the type used for the production of foam for the purpose of fire prevention and suppression.
BACKGROUND
For some time foaming agents have been used to increase the effectiveness of water in the prevention and suppression of fires. Systems have traditionally used foaming agents, commonly known as surfactants, mixed in holding tanks or introduced into the water stream by a variety of methods. More recently systems have been developed which also provide for the injection of compressed air into the water/surfactant mixture to provide an improved quality and volume of foam and which are typically referred to as compressed air foam systems or CAFS.
In a portable configuration of a compressed air foam system it is known to provide a holding tank for receiving a mixture of water and surFactant therein from which a flow is generated. Compressed air is then injected into the flow of solution from the holding tank. In a small portable system, it is desirable for batch mixing of the surfactant and water in the holding tank which typically requires careful measuring of the surfactant prior to placement in the tank with water. Such measurement is typically required to be done manually such that messy measuring equipment must also be transported with the system. Furthermore such manual measurement can be time consuming and inaccurate.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough;
a compressed air source arranged for supplying compressed air into the solution of water and surfactant; and an injector arranged for injecting a prescribed amount of surfactant from the surfactant source to the foam solution tank, the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive the prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
According to a second aspect of the present invention there is provided a surfactant injector arranged for use with a compressed air foam system, the compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough; and a compressed air source arranged for supplying compressed air into the solution of water and surfactant;
the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surFactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive a prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
According to another aspect of the invention there is provided a method of injecting a surfactant in a compressed air foam system comprising a foam solution tank, a source of water to be supplied to the tank, a source of surfactant to be supplied to the tank, an outlet line arranged for receiving a solution of water and surfactant from the tank therethrough, and a compressed air source arranged for supplying compressed air into the solution of water and surfactant to produce a foam, the method including:
providing an injector comprising a hollow body having inner walls defining an injector chamber and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
providing an inlet port in communication between the surfactant source and the injector chamber;
providing an outlet port in communication between the injector chamber and the foam solution tank;
sliding the piston relative to the inner walls in a first direction to receive a prescribed amount of surfactant in the injector chamber from the surfactant source 5 through the inlet port; and sliding the piston relative to the inner walls in a second direction to inject the prescribed amount of surfactant from the injector chamber through the outlet port.
By providing a surfactant injector in communication with the foam solution tank of a compressed air foam system which is arranged to inject a prescribed amount of surfactant corresponding to a batch to be mixed in the tank a more accurate measurement of surfactant can be accomplished. Furthermore by arranging the injector to comprise a piston which may be manually operated, a low cost and easy to use injector is provided which can be used quickly and readily repeated without concern for spills or auxiliary measuring equipment being required as in prior art configurations of compressed air foam systems.
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a compressed air foam system according to the present invention.
Figure 2 is a top plan view of the system.
According to one aspect of the invention there is provided a compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough;
a compressed air source arranged for supplying compressed air into the solution of water and surfactant; and an injector arranged for injecting a prescribed amount of surfactant from the surfactant source to the foam solution tank, the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive the prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
According to a second aspect of the present invention there is provided a surfactant injector arranged for use with a compressed air foam system, the compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough; and a compressed air source arranged for supplying compressed air into the solution of water and surfactant;
the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surFactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive a prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
According to another aspect of the invention there is provided a method of injecting a surfactant in a compressed air foam system comprising a foam solution tank, a source of water to be supplied to the tank, a source of surfactant to be supplied to the tank, an outlet line arranged for receiving a solution of water and surfactant from the tank therethrough, and a compressed air source arranged for supplying compressed air into the solution of water and surfactant to produce a foam, the method including:
providing an injector comprising a hollow body having inner walls defining an injector chamber and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
providing an inlet port in communication between the surfactant source and the injector chamber;
providing an outlet port in communication between the injector chamber and the foam solution tank;
sliding the piston relative to the inner walls in a first direction to receive a prescribed amount of surfactant in the injector chamber from the surfactant source 5 through the inlet port; and sliding the piston relative to the inner walls in a second direction to inject the prescribed amount of surfactant from the injector chamber through the outlet port.
By providing a surfactant injector in communication with the foam solution tank of a compressed air foam system which is arranged to inject a prescribed amount of surfactant corresponding to a batch to be mixed in the tank a more accurate measurement of surfactant can be accomplished. Furthermore by arranging the injector to comprise a piston which may be manually operated, a low cost and easy to use injector is provided which can be used quickly and readily repeated without concern for spills or auxiliary measuring equipment being required as in prior art configurations of compressed air foam systems.
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a compressed air foam system according to the present invention.
Figure 2 is a top plan view of the system.
Figure 3 is an end elevational view of the system.
Figure 4 is a side elevational view of the system.
Figure 5 is a sectional view along the line 5-5 of Figure 4.
Figure 6 is a top plan view of the water supply fitting.
Figure 7 is a sectional view along the line 7-7 of Figure 6.
Figure 8 is a top plan view of the surfactant injector.
Figure 9 is a sectional view along the line 9-9 of Figure 8.
Figure 10 is longitudinal cross sectional view of the outlet fitting.
Figure 11 is a schematic representation of the system.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated a compressed air foam system generally indicated by reference numeral 10. The system 10 is suited for the production of foam for fire prevention and suppression.
The system 10 comprises a portable frame comprised of two end frames 12 comprising perimeter tubing extending about a square perimeter of each end frame 12. A plurality of rigid rails 14 extend between the two end frames 12 to connect between corresponding corners of the end frames and to connect centrally between the top and bottom ends of the two opposed end frames for added structural rigidity.
Supported within the frame is a foam solution tank 16 which is generafly cylindrical in shape so as to extend horizontally between opposed ends 18 of the tank. The tank is suited for receiving a batch solution of water and surfactant mixture therein as well as receiving air under pressure to both drive a flow of the solution out of the tank and to assist in generating foam.
The frame includes a cradle 20 fixed on the bottom end thereof to support the tank wholly within the perimeter defined by the frame members of the frame. The tank includes an end cap 22 spanning across each of the two opposed ends 18 of the tank for enclosing a hollow interior of the tank.
A manifold 24 is provided at the'inlet one of the two ends 18 of the tank for communication through the end cap 22 supported thereon. The manifold generally comprises a T-connector having a main cylindrical body 26 and a stem extending from the cylindrical body for communication through the end cap and into the hollow interior of the tank.
A surfactant injector 30 communicates with one end of the main body 26 of the manifold and a water supply fitting 32 communicates with the other end of the cylindrical body 26 of the manifold opposite the surfactant injector.
The surfactant injector 30 includes an injector body 34 having a cylindrical inner wall 36 which surrounds a hollow interior extending axially through the body between an inner end 38 connected to the manifold 24 and an opposed outer end 40.
The hollow interior of the injector body 34 comprises an injector chamber 42 which is arranged to meter a prescribed amount of surfactant to be injected from a surfactant source 44 into the tank 16.
A one way check valve 46 spans an inner end of the injector body which defines an outlet port 47 in communication in an axial direction the injector chamber 42 and the manifold 24. The check valve 46 comprises a fixed plate 48 spanning the open end of the hollow body in sealing engagement therewith about a periphery of the plate by an annular channel 50 in the peripheral edge of the plate which receives a suitable 0-ring 52 therein for sealing engagement between the fixed plate 48 and the inner walls of the injector body.
A plurality of apertures 54 are provided in a circumferential pattern about a central axis of the hollow body and fixed plate through which surfactant may be communicated from the injector chamber 42 into the manifold. A stem 56 is mounted centrally on the fixed plate 48 to extend from an inner side or manifold side of the fixed plate 42 onto which a moveable plate 58 is slidably mounted. The moveable plate 58 is supported concentrically with the fixed plate but is smaller in diameter so as to define an annular gap about a periphery of the moveable plate through which surfactant can flow when the moveable plate and the fixed plate are spaced apart from one another.
The diameter of the moveable plate and the location of the apertures 54 in the fixed plate are arranged so that the plate overlaps the apertures and closes the apertures when the two plates are abutted against one another. A suitable spring 60 serves to bias the moveable plate into engagement against the fixed plate for closing the apertures in the fixed plate and in turn closing the one way check ~~ . . ,~. _.,~,.~....~H _~.~... ~ a , ..,...,.~.~.. ~. . . .. . _ . .... _ .
_ 9 =
valve 46. Pressure on the manifold side of the valve further urges the two plates together to maintain the valve in a closed position, however increased pressure on the injector chamber side of the one way check valve causes fluid under pressure to communicate through the apertures and displace the moveable plate away from the fixed plate against the biasing of the spring 60 to open the valve.
The injector body also includes an inlet port 62 which communicate radially through the inner wall of the cylindrical hollow body adjacent the inner end thereof. The inlet port 62 communicates between the surfactant source 44 and the hollow interior of the injector chamber. A one way check valve 64 is provided in series with the inlet port 62 and is oriented to only permit flow in a direction from the source into the injector chamber through the inlet port.
A piston 66 is slidably mounted within the injector chamber of the injector for relative sliding movement along a sliding axis extending axially through the cylindrical body of the injector. The piston 66 includes a cylindrical head 68 which spans across a cross section of the cylindrical inner walls. The cylindrical head 68 is supported for sliding movement along the longitudinal axis of the cylinder shape of the inner walls between the inner and outer end of the injector body.
An annular channel 70 is provided about the periphery of the cylindrical head to receive a suitable 0-ring 72 which provides sealing engagement between the cylindrical head 68 of the piston and the inner walls of the injector chamber throughout sliding movement of the piston in the longitudinal direction of the cylindrical body.
The piston also includes a shaft 74 extending along the longitudinal axis of sliding movement of the piston relative to the injector body from the cylindrical head 68 through the outer end 40 of the housing to an extemal handle 76.
The handle 76 is arranged to be manually grasped by a user for manually displacing the piston in a sliding movement along the sliding axis thereof relative to the 5 surrounding inner wall of the injector body. The handle 76 generally comprises a stem which is oriented perpendicularly to the shaft 74 of the piston so as to be generally T-shaped with the shaft of the piston.
A guide plate 78 is mounted to span across the outer end of the cylindrical body of the injector for slidably receiving the shaft 74 therethrough. A
Figure 4 is a side elevational view of the system.
Figure 5 is a sectional view along the line 5-5 of Figure 4.
Figure 6 is a top plan view of the water supply fitting.
Figure 7 is a sectional view along the line 7-7 of Figure 6.
Figure 8 is a top plan view of the surfactant injector.
Figure 9 is a sectional view along the line 9-9 of Figure 8.
Figure 10 is longitudinal cross sectional view of the outlet fitting.
Figure 11 is a schematic representation of the system.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated a compressed air foam system generally indicated by reference numeral 10. The system 10 is suited for the production of foam for fire prevention and suppression.
The system 10 comprises a portable frame comprised of two end frames 12 comprising perimeter tubing extending about a square perimeter of each end frame 12. A plurality of rigid rails 14 extend between the two end frames 12 to connect between corresponding corners of the end frames and to connect centrally between the top and bottom ends of the two opposed end frames for added structural rigidity.
Supported within the frame is a foam solution tank 16 which is generafly cylindrical in shape so as to extend horizontally between opposed ends 18 of the tank. The tank is suited for receiving a batch solution of water and surfactant mixture therein as well as receiving air under pressure to both drive a flow of the solution out of the tank and to assist in generating foam.
The frame includes a cradle 20 fixed on the bottom end thereof to support the tank wholly within the perimeter defined by the frame members of the frame. The tank includes an end cap 22 spanning across each of the two opposed ends 18 of the tank for enclosing a hollow interior of the tank.
A manifold 24 is provided at the'inlet one of the two ends 18 of the tank for communication through the end cap 22 supported thereon. The manifold generally comprises a T-connector having a main cylindrical body 26 and a stem extending from the cylindrical body for communication through the end cap and into the hollow interior of the tank.
A surfactant injector 30 communicates with one end of the main body 26 of the manifold and a water supply fitting 32 communicates with the other end of the cylindrical body 26 of the manifold opposite the surfactant injector.
The surfactant injector 30 includes an injector body 34 having a cylindrical inner wall 36 which surrounds a hollow interior extending axially through the body between an inner end 38 connected to the manifold 24 and an opposed outer end 40.
The hollow interior of the injector body 34 comprises an injector chamber 42 which is arranged to meter a prescribed amount of surfactant to be injected from a surfactant source 44 into the tank 16.
A one way check valve 46 spans an inner end of the injector body which defines an outlet port 47 in communication in an axial direction the injector chamber 42 and the manifold 24. The check valve 46 comprises a fixed plate 48 spanning the open end of the hollow body in sealing engagement therewith about a periphery of the plate by an annular channel 50 in the peripheral edge of the plate which receives a suitable 0-ring 52 therein for sealing engagement between the fixed plate 48 and the inner walls of the injector body.
A plurality of apertures 54 are provided in a circumferential pattern about a central axis of the hollow body and fixed plate through which surfactant may be communicated from the injector chamber 42 into the manifold. A stem 56 is mounted centrally on the fixed plate 48 to extend from an inner side or manifold side of the fixed plate 42 onto which a moveable plate 58 is slidably mounted. The moveable plate 58 is supported concentrically with the fixed plate but is smaller in diameter so as to define an annular gap about a periphery of the moveable plate through which surfactant can flow when the moveable plate and the fixed plate are spaced apart from one another.
The diameter of the moveable plate and the location of the apertures 54 in the fixed plate are arranged so that the plate overlaps the apertures and closes the apertures when the two plates are abutted against one another. A suitable spring 60 serves to bias the moveable plate into engagement against the fixed plate for closing the apertures in the fixed plate and in turn closing the one way check ~~ . . ,~. _.,~,.~....~H _~.~... ~ a , ..,...,.~.~.. ~. . . .. . _ . .... _ .
_ 9 =
valve 46. Pressure on the manifold side of the valve further urges the two plates together to maintain the valve in a closed position, however increased pressure on the injector chamber side of the one way check valve causes fluid under pressure to communicate through the apertures and displace the moveable plate away from the fixed plate against the biasing of the spring 60 to open the valve.
The injector body also includes an inlet port 62 which communicate radially through the inner wall of the cylindrical hollow body adjacent the inner end thereof. The inlet port 62 communicates between the surfactant source 44 and the hollow interior of the injector chamber. A one way check valve 64 is provided in series with the inlet port 62 and is oriented to only permit flow in a direction from the source into the injector chamber through the inlet port.
A piston 66 is slidably mounted within the injector chamber of the injector for relative sliding movement along a sliding axis extending axially through the cylindrical body of the injector. The piston 66 includes a cylindrical head 68 which spans across a cross section of the cylindrical inner walls. The cylindrical head 68 is supported for sliding movement along the longitudinal axis of the cylinder shape of the inner walls between the inner and outer end of the injector body.
An annular channel 70 is provided about the periphery of the cylindrical head to receive a suitable 0-ring 72 which provides sealing engagement between the cylindrical head 68 of the piston and the inner walls of the injector chamber throughout sliding movement of the piston in the longitudinal direction of the cylindrical body.
The piston also includes a shaft 74 extending along the longitudinal axis of sliding movement of the piston relative to the injector body from the cylindrical head 68 through the outer end 40 of the housing to an extemal handle 76.
The handle 76 is arranged to be manually grasped by a user for manually displacing the piston in a sliding movement along the sliding axis thereof relative to the 5 surrounding inner wall of the injector body. The handle 76 generally comprises a stem which is oriented perpendicularly to the shaft 74 of the piston so as to be generally T-shaped with the shaft of the piston.
A guide plate 78 is mounted to span across the outer end of the cylindrical body of the injector for slidably receiving the shaft 74 therethrough. A
10 central opening 80 closely fits the cross section of the shaft therethrough for slidi-ig movement along the sliding axis of the piston. The guide plate 78 is received within a counter bore formed in the outer end of the cylindrical body to be held in place by a suitable snap ring 82 received within a respective groove formed on the inner walls of the cylindrical body.
The piston 66 is arranged for sliding movement between a first position adjacent the inner end of the injector body as shown in solid line in Figure 9 and a second position adjacent the outer end of the cylindrical body as shown in broken in Figure 9. The piston is slidable along the sliding axis of the injector body in a first direction corresponding to loading or charging of the injector chamber by displacement of the cylindrical head of the piston form the first position to the second position. When displacing the piston in the first direction, the check valve 46 at the outer end of the body, which spans across the outlet port, prevents fluid from entering the injector chamber through the outlet port, however the one way check valve 64 in the inlet port 62 readily opens to draw surfactant from the source 44 to fill the injector chamber with a prescribed amount of surfactant. The prescribed amount of surfactant corresponds to the specified amount of surfactant or foaming agent to be mixed with water to form a solution when filling the tank with the solution.
The piston is also moveable a second direction from the second position to the first position in which the volume of the injector chamber is reduced so that the prescribed amount of surfactant previously drawn into the injector chamber is now injected out of the injector chamber and into the manifold for communication into the tank. The pressure exerted on the surfactant in the injector chamber when displacing the piston in the second direction causes the check valve 46 at the outlet port in the injector body to be opened to allow the flow of surfactant into the manifold, however the one way check valve 64 in the inlet port 62 prevents the surfactant from being forced back through the inlet port towards the source of surfactant.
The water supply fitting as shown in Figures 6 and 7 also comprises a generally cylindrical body 84 extending in an axial direction between an inner end in communication with the manifold and an outer end which is enclosed. A one way check valve 86 is mounted to span across the inner end in communication between the hollow interior of the body 84 and the manifold which is identical in configuration to the one way valve 46 at the inner end of the injector body.
At the outer end of the water supply fitting, there is provided an end plate 88 which is received within a counter bore formed at the outer end of the cylindrical body. A suitable channel is formed about the periphery of the end plate 88 for receiving an 0-ring sealing member 90 for sealing engagement between the end plate 80 and the surrounding inner walls of the cylindrical body of the water supply fitting. A suitable snap spring 92 serves to retain the end plate 88 in place within the outer bore when the snap ring is received within a respective groove in the body.
A pair of side ports 94 communicate through the cylindrical walls of the body of the water supply fitting at diametrically opposed locations evenly spaced between the inner and outer ends of the cylindrical body. Each of the side ports is internally threaded for suitable connection to a water supply. The water supply may be connected by various hoses or fitting which are threadably connected to the side port 94 of the water supply fitting. The one way check valve 86 is oriented such that fluid under pressure within the manifold will not be permitted to flow back into the hollow interior of the water supply fitting from the manifold, however water supplied under pressure into the side ports 94 of the water supply fitting will urge the moveable plate away from the fixed plate of the check valve 86 to allow flow of water from the water supply fitting into the manifold.
Air is arranged to be supplied into the foam solution tank 16 through a suitable three-way valve 96 which controls the flow of air to and from the tank during various loading or discharging cycles of the tank. A main line 98 communicates between the three-way valve and a stem 100 which communicates through the end cap to an open end located inside the tank adjacent the top end thereof. The three-way valve also communicated with a vent line 102 which is open to atmosphere for venting excess pressure or excess air from the tank when desired.
A pressure line 104 also communicates with the three-way valve for connection between the three-way valve and a suitable pressure regulator 106.
The pressure regulator 106 receives air from compressed air source 108 which communicates through a one way check valve 110 to the regulator 106 and in turn through the pressure line 104 to the three-way valve. The one way valve 110 only permits flow from the compressed air source to the tank.
In a first position of the three-way valve corresponding to a venting position, the main line 98 communicates with the vent line 102 for venting air from the open end of the stem inside the tank to atmosphere at the vent line. The three-way valve 96 may alternatively be positioned in a supply position in which the pressure line 104 communicates with the stem 100 in the tank through the main line 98 and the vent line 102 is closed. In this instance air under pressure from the compressed air source can be introduced into the interior of the foam solution tank.
The compressed air source 108 in the illustrated embodiment comprises a pair of canisters 112 locating air therein under pressure for being dispensed therefrom when appropriate valves on the canisters are opened.
At an outlet one of the ends 18 of the foam solution tank 16 an outlet line 114 communicates through the end cap between the hollow interior of the tank and an outlet fitting 116. The outlet fitting is generally cylindrical having a hollow passage extending therethrough between opposed ends 118 of the body. A side port 120 communicates radially through the side wall in outlet fitting 116.
The side port 120 communicates with the source of compressed air 108 to introduce compressed air into a flow of solution through the outlet line 114 which passes through the outlet fitting 116.
Between the opposing ends 118 of the outlet fitting there is also provided a restrictor nozzle 122 through which the flow of solution in the outlet line must pass prior to being dispensed by the system. The aperture of the restrictor nozzle 120 is selected by replacing the restrictor nozzle with different sizes of nozzles so that the size of the aperture can be adjusted relative to the compressed air injected into the outlet line. The ratio of surfactant and water solution relative to auxiliary compressed air injected into the solution can thus be varied which in turn varies the characteristics of the foam being dispensed by the system between a wet foam and a dry foam condition.
A shutoff valve 124 communicates with the outlet line 114 downstream the outlet fitting for shutting off the flow exiting the tank as desired. When the shutoff valve 124 is opened, flow of the solution with compressed air injected therein is directed from the outlet line through the shutoff valve to a suitable dispensing hose.
In use, the three-way valve 96 of the air control system is initially positioned in the vent position to vent the interior of the tank to atmosphere when the tank is empty. The shutoff valve 124 at the outlet end of the tank is closed to permit charging of the tank with a new solution of foaming agent or surfactant and water.
The user first manually displaces the piston of the injector in the first direction from the first end to the second end of the body to draw surfactant under suction from the surfactant source through the inlet port and into the injector chamber. The displacement volume of the piston precisely draws a prescribed 5 amount of the surfactant into the injector chamber which corresponds to the desired amount of surfactant to be mixed with water in the tank when filling the tank.
Subsequently manually displacing the piston in the second direction from the second end to the first end of the injector body causes the prescribed amount of surfactant in the injector chamber to be injected through the outlet port 10 and into the manifold 24 at the inlet end of the foam solution tank. Water is then introduced into the water supply fitting and through the manifold to collect the prescribed amount of surfactant injected into the manifold as the water flows into the tank and fills the tank. The water suitably mixes with the surfactant as it flows through the manifold and collects the surfactant injected therein.
The piston 66 is arranged for sliding movement between a first position adjacent the inner end of the injector body as shown in solid line in Figure 9 and a second position adjacent the outer end of the cylindrical body as shown in broken in Figure 9. The piston is slidable along the sliding axis of the injector body in a first direction corresponding to loading or charging of the injector chamber by displacement of the cylindrical head of the piston form the first position to the second position. When displacing the piston in the first direction, the check valve 46 at the outer end of the body, which spans across the outlet port, prevents fluid from entering the injector chamber through the outlet port, however the one way check valve 64 in the inlet port 62 readily opens to draw surfactant from the source 44 to fill the injector chamber with a prescribed amount of surfactant. The prescribed amount of surfactant corresponds to the specified amount of surfactant or foaming agent to be mixed with water to form a solution when filling the tank with the solution.
The piston is also moveable a second direction from the second position to the first position in which the volume of the injector chamber is reduced so that the prescribed amount of surfactant previously drawn into the injector chamber is now injected out of the injector chamber and into the manifold for communication into the tank. The pressure exerted on the surfactant in the injector chamber when displacing the piston in the second direction causes the check valve 46 at the outlet port in the injector body to be opened to allow the flow of surfactant into the manifold, however the one way check valve 64 in the inlet port 62 prevents the surfactant from being forced back through the inlet port towards the source of surfactant.
The water supply fitting as shown in Figures 6 and 7 also comprises a generally cylindrical body 84 extending in an axial direction between an inner end in communication with the manifold and an outer end which is enclosed. A one way check valve 86 is mounted to span across the inner end in communication between the hollow interior of the body 84 and the manifold which is identical in configuration to the one way valve 46 at the inner end of the injector body.
At the outer end of the water supply fitting, there is provided an end plate 88 which is received within a counter bore formed at the outer end of the cylindrical body. A suitable channel is formed about the periphery of the end plate 88 for receiving an 0-ring sealing member 90 for sealing engagement between the end plate 80 and the surrounding inner walls of the cylindrical body of the water supply fitting. A suitable snap spring 92 serves to retain the end plate 88 in place within the outer bore when the snap ring is received within a respective groove in the body.
A pair of side ports 94 communicate through the cylindrical walls of the body of the water supply fitting at diametrically opposed locations evenly spaced between the inner and outer ends of the cylindrical body. Each of the side ports is internally threaded for suitable connection to a water supply. The water supply may be connected by various hoses or fitting which are threadably connected to the side port 94 of the water supply fitting. The one way check valve 86 is oriented such that fluid under pressure within the manifold will not be permitted to flow back into the hollow interior of the water supply fitting from the manifold, however water supplied under pressure into the side ports 94 of the water supply fitting will urge the moveable plate away from the fixed plate of the check valve 86 to allow flow of water from the water supply fitting into the manifold.
Air is arranged to be supplied into the foam solution tank 16 through a suitable three-way valve 96 which controls the flow of air to and from the tank during various loading or discharging cycles of the tank. A main line 98 communicates between the three-way valve and a stem 100 which communicates through the end cap to an open end located inside the tank adjacent the top end thereof. The three-way valve also communicated with a vent line 102 which is open to atmosphere for venting excess pressure or excess air from the tank when desired.
A pressure line 104 also communicates with the three-way valve for connection between the three-way valve and a suitable pressure regulator 106.
The pressure regulator 106 receives air from compressed air source 108 which communicates through a one way check valve 110 to the regulator 106 and in turn through the pressure line 104 to the three-way valve. The one way valve 110 only permits flow from the compressed air source to the tank.
In a first position of the three-way valve corresponding to a venting position, the main line 98 communicates with the vent line 102 for venting air from the open end of the stem inside the tank to atmosphere at the vent line. The three-way valve 96 may alternatively be positioned in a supply position in which the pressure line 104 communicates with the stem 100 in the tank through the main line 98 and the vent line 102 is closed. In this instance air under pressure from the compressed air source can be introduced into the interior of the foam solution tank.
The compressed air source 108 in the illustrated embodiment comprises a pair of canisters 112 locating air therein under pressure for being dispensed therefrom when appropriate valves on the canisters are opened.
At an outlet one of the ends 18 of the foam solution tank 16 an outlet line 114 communicates through the end cap between the hollow interior of the tank and an outlet fitting 116. The outlet fitting is generally cylindrical having a hollow passage extending therethrough between opposed ends 118 of the body. A side port 120 communicates radially through the side wall in outlet fitting 116.
The side port 120 communicates with the source of compressed air 108 to introduce compressed air into a flow of solution through the outlet line 114 which passes through the outlet fitting 116.
Between the opposing ends 118 of the outlet fitting there is also provided a restrictor nozzle 122 through which the flow of solution in the outlet line must pass prior to being dispensed by the system. The aperture of the restrictor nozzle 120 is selected by replacing the restrictor nozzle with different sizes of nozzles so that the size of the aperture can be adjusted relative to the compressed air injected into the outlet line. The ratio of surfactant and water solution relative to auxiliary compressed air injected into the solution can thus be varied which in turn varies the characteristics of the foam being dispensed by the system between a wet foam and a dry foam condition.
A shutoff valve 124 communicates with the outlet line 114 downstream the outlet fitting for shutting off the flow exiting the tank as desired. When the shutoff valve 124 is opened, flow of the solution with compressed air injected therein is directed from the outlet line through the shutoff valve to a suitable dispensing hose.
In use, the three-way valve 96 of the air control system is initially positioned in the vent position to vent the interior of the tank to atmosphere when the tank is empty. The shutoff valve 124 at the outlet end of the tank is closed to permit charging of the tank with a new solution of foaming agent or surfactant and water.
The user first manually displaces the piston of the injector in the first direction from the first end to the second end of the body to draw surfactant under suction from the surfactant source through the inlet port and into the injector chamber. The displacement volume of the piston precisely draws a prescribed 5 amount of the surfactant into the injector chamber which corresponds to the desired amount of surfactant to be mixed with water in the tank when filling the tank.
Subsequently manually displacing the piston in the second direction from the second end to the first end of the injector body causes the prescribed amount of surfactant in the injector chamber to be injected through the outlet port 10 and into the manifold 24 at the inlet end of the foam solution tank. Water is then introduced into the water supply fitting and through the manifold to collect the prescribed amount of surfactant injected into the manifold as the water flows into the tank and fills the tank. The water suitably mixes with the surfactant as it flows through the manifold and collects the surfactant injected therein.
15 The vent position of the three-way valve allows excess air in the tank to be vented to atmosphere until the tank is full with water at which point the three-way valve is switched to a supply position. The source of water is shutoff once the tank is full so that the tank can then be charged with air under pressure.
Compressed air is directed through the pressure regulator 106 to limit the pressure in the tank to a prescribed pressure. In the supply position of the three-way valve the source of compressed air permits a sufficient amount of air under pressure to be supplied into the tank to pressurize the tank with a driving pressure which is sufficient such that subsequent opening of the shutoff valve at the outlet end of the tank causes a flow of foam solution to exit the tank 16 under the action of the pressure introduced into the tank through the three-way valve 96.
Auxiliary compressed air is injected in the outlet line to enhance the expansion and quality of the foam being dispensed by the system. Once the tank is emptied and no longer under pressure the steps of the filling cycle noted above can be repeated. When refilling the tank, a single reciprocation of the piston between the first and second ends of the injector body is sufficient to collect a prescribed amount of surfactant from the source and then subsequently inject that prescribed amount into the manifold for dispensing into the tank by the subsequent flow of water which fills the tank.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
Compressed air is directed through the pressure regulator 106 to limit the pressure in the tank to a prescribed pressure. In the supply position of the three-way valve the source of compressed air permits a sufficient amount of air under pressure to be supplied into the tank to pressurize the tank with a driving pressure which is sufficient such that subsequent opening of the shutoff valve at the outlet end of the tank causes a flow of foam solution to exit the tank 16 under the action of the pressure introduced into the tank through the three-way valve 96.
Auxiliary compressed air is injected in the outlet line to enhance the expansion and quality of the foam being dispensed by the system. Once the tank is emptied and no longer under pressure the steps of the filling cycle noted above can be repeated. When refilling the tank, a single reciprocation of the piston between the first and second ends of the injector body is sufficient to collect a prescribed amount of surfactant from the source and then subsequently inject that prescribed amount into the manifold for dispensing into the tank by the subsequent flow of water which fills the tank.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
Claims (20)
1. A compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough;
a compressed air source arranged for supplying compressed air into the solution of water and surfactant; and an injector arranged for injecting a prescribed amount of surfactant from the surfactant source to the foam solution tank, the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive the prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough;
a compressed air source arranged for supplying compressed air into the solution of water and surfactant; and an injector arranged for injecting a prescribed amount of surfactant from the surfactant source to the foam solution tank, the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive the prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
2. The system according to Claim 1 wherein the piston is arranged to be manually displaced relative to the inner walls of the body of the injector.
3. The system according to Claim 2 wherein there is provided a manual handle supported externally of the hollow body of the injector and connected to the piston for sliding movement therewith.
4. The system according to Claim 1 wherein there is provided a one way valve in communication with the outlet port which is arranged to only permit flow out of the injector chamber.
5. The system according to Claim 1 wherein there is provided a one way valve in communication with the inlet port which is arranged to only permit flow into the injector chamber from the surfactant source.
6. The system according to Claim 1 wherein the surfactant source is arranged to be maintained at atmospheric pressure.
7. The system according to Claim 1 wherein there is provided a manifold in communication with the foam solution tank, the outlet port of the injector and the water source being arranged to communicate with the tank through the manifold.
8. The system according to Claim 1 wherein the prescribed amount corresponds to a size of the foam solution tank.
9. The system according to Claim 1 wherein the prescribed amount corresponds to an amount of surfactant to be mixed with water in a solution when the tank is full.
10. The system according to Claim 1 wherein the piston is slidable along a sliding axis of the injector and wherein the inlet port extends through a respective inner wall of the hollow body in a radial direction relative to the sliding axis.
11. The system according to Claim 1 wherein the piston is arranged for sliding movement along a sliding axis of the injector and wherein the outlet port extends in a direction of the sliding axis through one end of the hollow body.
12. The system according to Claim 1 wherein the piston is arranged for sliding movement along a sliding axis of the injector and wherein the inner walls are generally cylindrical about the sliding axis, the inlet port being arranged to communicate through the cylindrical wall of the hollow body and the outlet being arranged to communicate axially through one end of the hollow body.
13. The system according to Claim 1 wherein both the inlet port and the outlet port remain in communication with the hollow interior of the injector chamber through a full range of sliding movement of the piston relative to the hollow body of the injector.
14. A surfactant injector arranged for use with a compressed air foam system, the compressed air foam system comprising:
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough; and a compressed air source arranged for supplying compressed air into the solution of water and surfactant;
the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive a prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
a foam solution tank;
a water source arranged for supplying water to the foam solution tank;
a surfactant source arranged for supplying surfactant to the foam solution tank;
an outlet line arranged for receiving a solution of water and surfactant from the foam solution tank therethrough; and a compressed air source arranged for supplying compressed air into the solution of water and surfactant;
the injector comprising:
a hollow body having inner walls defining an injector chamber;
an inlet port arranged to communicate between the surfactant source and the injector chamber;
an outlet port arranged to communicate between the injector chamber and the foam solution tank; and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
the injector chamber being arranged to receive a prescribed amount of surfactant from the surfactant source through the inlet port responsive to sliding movement of the piston relative to the inner walls in a first direction; and the piston being arranged to inject the prescribed amount of surfactant from the injector chamber through the outlet port responsive to sliding movement of the piston relative to the inner walls in a second direction.
15. A method of injecting a surfactant in a compressed air foam system comprising a foam solution tank, a source of water to be supplied to the tank, a source of surfactant to be supplied to the tank, an outlet line arranged for receiving a solution of water and surfactant from the tank therethrough, and a compressed air source arranged for supplying compressed air into the solution of water and surfactant to produce a foam, the method including:
providing an injector comprising a hollow body having inner walls defining an injector chamber and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
providing an inlet port in communication between the surfactant source and the injector chamber;
providing an outlet port in communication between the injector chamber and the foam solution tank;
sliding the piston relative to the inner walls in a first direction to receive a prescribed amount of surfactant in the injector chamber from the surfactant source through the inlet port; and sliding the piston relative to the inner walls in a second direction to inject the prescribed amount of surfactant from the injector chamber through the outlet port.
providing an injector comprising a hollow body having inner walls defining an injector chamber and a piston supported in the injector chamber so as to be arranged for sliding movement relative to the inner walls in sealing engagement with the inner walls;
providing an inlet port in communication between the surfactant source and the injector chamber;
providing an outlet port in communication between the injector chamber and the foam solution tank;
sliding the piston relative to the inner walls in a first direction to receive a prescribed amount of surfactant in the injector chamber from the surfactant source through the inlet port; and sliding the piston relative to the inner walls in a second direction to inject the prescribed amount of surfactant from the injector chamber through the outlet port.
16. The method according to Claim 15 including manually driving sliding movement of the piston relative to the inner walls of the hollow body.
17. The method according to Claim 15 including sliding the piston in the second direction to inject the prescribed amount of surfactant prior to filing the foam solution tank with water from the source of water.
18. The method according to Claim 15 including providing a manifold in communication with the foam solution tank, injecting the prescribed amount surfactant through the outlet port into the manifold and filling the foam solution tank with water through the manifold.
19. The method according to Claim 15 wherein the prescribed amount corresponds to an amount of surfactant to be mixed with water in a solution when the foam solution tank is full.
20. The method according to Claim 15 including reciprocating the piston in the first and second directions only once during filling of the tank with water.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US4326708P | 2008-04-08 | 2008-04-08 | |
| US61/043,267 | 2008-04-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2661671A1 true CA2661671A1 (en) | 2009-10-08 |
Family
ID=41161252
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2661671 Abandoned CA2661671A1 (en) | 2008-04-08 | 2009-04-06 | Surfactant injector for compressed air foam system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2661671A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104958847A (en) * | 2015-06-09 | 2015-10-07 | 公安部天津消防研究所 | Compressed air foam fire extinguishing device for large floating roof storage tank |
-
2009
- 2009-04-06 CA CA 2661671 patent/CA2661671A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104958847A (en) * | 2015-06-09 | 2015-10-07 | 公安部天津消防研究所 | Compressed air foam fire extinguishing device for large floating roof storage tank |
| CN104958847B (en) * | 2015-06-09 | 2018-05-15 | 公安部天津消防研究所 | Compressed air foam fire-extinguishing apparatus for large-scale floating roof tank |
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