Modular balanced foam flow system

• US 6,454,540 B1
• Filed: 03/31/2000
• Issued: 09/24/2002
• Est. Priority Date: 03/31/2000
• Status: Expired due to Term

• Current Assignee: Kovatch Mobile Equipment Corp. (AIP LLC)
• Original Assignee: Kovatch Mobile Equipment Corp. (AIP LLC)
• Inventors: Taylor, Richard L., Terefinko, John M.
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): Fastovsky, Leonid M
• Application Number:
  US09/539,855
• Time in Patent Office: 907 Days
• Field of Search: 417/46, 169/24, 169/14, 169/15, 169/13, 366/10, 700/275, 566/10
• US Class Current: 417/46
• CPC Class Codes: A62C 5/02 of foam
• CPC Class Codes: F04C 14/08 characterised by varying the rotational speed
• CPC Class Codes: F04C 2220/24 for metering throughflow
• CPC Class Codes: G05D 11/008 involving a fluid operating a pump motor
• CPC Class Codes: G05D 11/131 by measuring the values related to the quantity of the individual components G05D11/139 takes precedence

Abstract

A liquid injection arrangement for inserting a foaming agent into water for a fire fighting application, or a similar use, requires that metered quantities of a liquid chemical foamant or other agent be injected into a conduit assembly conveying a water stream. A desired concentration of foamant requires varying the foamant flow as a function of water flow. A tank holds a quantity of liquid chemical foamant, and at least one pump has an inlet port coupled to the tank and an outlet port coupled to the conduit assembly. A hydraulic motor drives the pump and a valve is coupled with the hydraulic motor and a source of pressurized hydraulic fluid. A sensor is placed adjacent to the outlet port of the pump to feed back a signal representing the pressure of the water flowing through the conduit assembly, and a control system is responsive to the signal and to a flow rate of water flowing through the conduit assembly, producing a signal for controlling a speed at which the hydraulic motor drives the foamant pump. A feed-back loop is provided that monitors the flow rate and pressure of the water in order to control the foamant flow. The foamant outlet and the water/foam outlet pressure sensor are placed at substantially the same position in the flow so that the foam addition can be controlled to produce an accurately metered quantity of the liquid foamant in the water stream exiting the conduit assembly and to maintain the desired concentration.

Claims

1. An apparatus in which metered quantities of one or more liquid chemical foamants are injected into at least one conduit assembly conveying a water stream so as to maintain a desired concentration of said chemical foamant in said water stream, comprising:

at least one tank for holding a quantity of said liquid chemical foamants;

at least one foam pump having an inlet port coupled to said tank and an outlet port coupled to said at least one conduit assembly;

a hydraulic motor connected in driving relation to said at least one foam pump;

a valve coupled with said hydraulic motor and a source of pressurized hydraulic fluid;

a first sensor operatively coupled to said at least one conduit assembly to sense the rate of flow of the water stream flowing through said at least one conduit assembly and producing a first signal representative of said water flow rate;

a second sensor operatively coupled to said at least one conduit assembly adjacent to said outlet port of said at least one foam pump to sense the pressure of both the water and foam chemical stream flowing through said at least one conduit assembly and producing a second signal representative of said water and foam chemical pressure; and

a control system responsive to said first signal and said second signal for producing a signal for controlling a speed at which said hydraulic motor is driving said at least one foam pump, such that a desired quantity of the liquid chemical foamant in the water stream exiting said at least one conduit assembly maintains said desired concentration.

2. An apparatus according to claim 1 wherein said control system includes a feed-back loop to monitor the flow rate and pressure of the water and adjust said hydraulic motor speed driving said foam pump and thereby to control the flow rate of said liquid chemical foamant.

3. An apparatus according to claim 1 wherein said at least one pump comprises a rotary gear pump.

4. An apparatus according to claim 2 wherein a proportional hydraulic flow valve operates as an output element of said feed-back loop.

5. An apparatus according to claim 1 wherein said control system comprises a conventional microprocessor including a programmed processor coupled to inputs including sensing and control devices, computational and logical means, a memory, and output control displays that are accessible to an operator.

6. An apparatus according to claim 1 comprising a plurality of storage tanks arranged in regulated flow communication with a header manifold so as to provide said liquid concentrate foamant to said header manifold.

7. An apparatus according to claim 6 wherein said plurality of tanks each include a different liquid concentrate foamant.

8. An apparatus according to claim 1 wherein said hydraulic motor is arranged in regulated flow communication with a hydraulic fluid manifold, and a proportional flow hydraulic flow valve, from which said hydraulic motor is provided with pressurized hydraulic fluid for sustained operation.

9. An apparatus according to claim 3 wherein said pump is capable of operation in the range from approximately 200 to 3600 revolutions per minute so as to accommodate corresponding breadth in the range of control for water flow between approximately 5% and 100% of its maximum capacity.

10. An apparatus according to claim 3 wherein said at least one pump is arranged in flow communication with a header manifold, so as to draw said liquid concentrate foamant during operation, and with a foamant conduit.

11. An apparatus according to claim 1 wherein a plurality of pumps are interconnected to a header manifold so as to draw said liquid concentrate foamant during operation, and with a plurality of foamant conduits.

12. An apparatus according to claim 10 comprising a water delivery system and an injection check valve operatively interconnected to a portion of said conduit, adjacent to an intersection between said conduit and said water delivery system.

13. An apparatus according to claim 12 wherein said water delivery system comprises:

a water pump disposed in regulated flow communication with a source of water and having a capacity in the range from approximately 40 to 3000 or more gallons per minute;

a discharge manifold interconnected in flow communication with a water discharge fixture;

a water conduit operatively coupled to a discharge flow meter, a discharge flow control valve, and a pressure transducer and adjacent to said injection check valve thereby allowing for the direct measurement of both the water pressure and foam pressure at a specific location along said water conduit where liquid foamant concentrate is introduced into said water.

14. An apparatus according to claim 13 wherein said pressure transducer is positioned within a wall of said water conduit.

15. An apparatus according to claim 1 wherein said liquid foamant concentrate is available for selection in the range is from about 0.1% to about 10%.

16. An apparatus in which metered quantities of a liquid chemical foamant are injected into a plurality of conduit assemblies conveying a water stream so as to maintain a desired concentration of said chemical foamant in said water stream, comprising:

a tank for holding a quantity of said liquid chemical foamant;

a plurality of rotary gear foam pumps each having an inlet port coupled to said tank and an outlet port coupled to one of said plurality of conduit assemblies;

a plurality of hydraulic motors each connected in driving relation to one of said plurality of rotary gear foam pumps;

a plurality of valves each coupled with one of said plurality of hydraulic motors and a source of pressurized hydraulic fluid;

a plurality of first sensors each operatively coupled to one of a plurality of said conduit assemblies to sense the rate of flow of a water stream flowing through said one of a plurality of conduit assemblies and producing a plurality of first signals representative of said water flow rate in each of said conduit assemblies;

a plurality of second sensors each operatively coupled to one of a plurality of conduit assemblies adjacent to said outlet port of each of a plurality of rotary gear foam pumps to sense the pressure of both the water and foam chemical stream flowing through each of said plurality of conduit assemblies and producing a plurality of second signals representative of said water and foam chemical pressure in each conduit assembly; and

a plurality of control systems each one responsive to said plurality of first signals and said plurality of second signals for producing a plurality of electrical signals each one for controlling a speed at which one of said plurality of hydraulic motors is driving one of said plurality of rotary gear foam pumps, such that a desired quantity of the liquid chemical foamant in the water stream exiting said plurality of conduit assemblies maintains said desired concentration.