Foam Proportioning System with Low-End Controller

• US 20090200045A1
• Filed: 01/05/2009
• Published: 08/13/2009
• Est. Priority Date: 01/03/2008
• Status: Active Grant

• Current Assignee: Fire Research Corp. (Safe Fleet Holdings LLC)
• Original Assignee: Sta-Rite Industries LLC (Pentair Plc (Ireland))
• Inventors: Hosfield, Robert L., Horeck, Robert S., Arvidson, Lawrence C.
• Granted Patent: US 7,997,348 B2
• Time in Patent Office: Days
• US Class Current: 169/44
• CPC Class Codes: A62C 5/02 of foam

Abstract

Embodiments of the invention provide a foam proportioning system. The foam proportioning system can include a foam pump, at least one foam line, a divert, and at least one controller. The divert can direct a portion of a flow of a liquid foam concentrate downstream of the foam pump back through the foam pump. The controller, which can be in communication with the foam pump and the divert, can be configured to automatically maintain a minimum flow rate of the liquid foam concentrate through the foam pump.

Claims

1. A foam proportioning system comprising:

a foam pump;

at least one foam line in fluid communication with at least one discharge line and the foam pump;

a divert having a recirculation line, the recirculation line having a first end positioned downstream of the foam pump and a second end positioned upstream of the foam pump, the divert operable to direct a portion of the flow of the liquid foam concentrate through the recirculation line; and

at least one controller in communication with the foam pump and divert, the controller configured to automatically operate the foam pump and the divert to maintain a minimum flow rate of the liquid foam concentrate through the foam pump.

2. The system of claim 1, wherein the divert includes a low-end control valve in communication with the at least one controller, the low-end control valve operating in response to a signal from the controller.

3. The system of claim 2, wherein the low-end control valve is automatically opened when a foam demand is less than the minimum flow rate.

4. The system of claim 2, wherein the low-end control valve is a ball valve.

5. The system of claim 1, wherein the at least one controller automatically maintains a proportioning rate between a flow of water in the at least one discharge line and a flow of liquid foam concentrate into the flow of water.

6. The system of claim 5, wherein the controller operates the divert in response to the proportioning rate.

7. The system of claim 1, wherein the divert includes a low-end flow meter in communication with the at least one controller, the low-end flow meter operable to monitor a flow rate of the liquid foam concentrate through the divert.

8. The system of claim 1, and further comprising a pressure transducer in the at least one foam line, the pressure transducer being in communication with the at least one controller.

9. The system of claim 8, wherein the at least one controller stops the foam pump when a signal from the pressure transducer indicates an overpressure in the at least one foam line.

10. The system of claim 1, and further comprising a manifold connecting the at least one foam line to a plurality of water lines.

11. The system of claim 1, wherein each foam line is in fluid communication with a corresponding discharge line.

12. The system of claim 11, wherein each foam line provides an individual proportioning rate to the corresponding discharge line.

13. A method of operating a foam proportioning system, the method comprising:

sensing a water flow rate through at least one discharge line;

determining an appropriate foam flow rate to the at least water discharge line in order to maintain a predetermined concentration of liquid foam concentrate in a water stream;

operating a foam pump to supply a flow of the liquid foam concentrate, the foam pump being operable down to a minimum flow rate; and

automatically diverting a portion of the flow of the liquid foam concentrate back through an inlet of the foam pump when the appropriate foam flow rate is less than the minimum flow rate of the foam pump.

14. The method of claim 13, and further comprising sensing the foam flow rate through the foam pump.

15. The method of claim 13, and further comprising sensing the foam flow rate in at least one foam line conveying the liquid foam concentrate.

16. The method of claim 15, and further comprising automatically adjusting operation of the foam pump and diversion of the liquid foam concentrate to maintain the minimum flow rate through the foam pump and the appropriate flow rate through the at least one foam line.

17. The method of claim 13, and further comprising sensing a flow rate of the diverted portion of the flow of the liquid foam concentrate.