No water / dead head detection pump protection algorithm

• US 20070160480A1
• Filed: 01/06/2006
• Published: 07/12/2007
• Est. Priority Date: 01/06/2006
• Status: Active Grant

• Current Assignee: Xylem Ip Holdings LLC (Xylem, Inc.)
• Original Assignee: ITT Industries (ITT, Inc.)
• Inventors: Ruffo, Matthew
• Granted Patent: US 8,011,895 B2
• Time in Patent Office: Days
• US Class Current: 417/44.200
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0236 Lack of liquid level being detected by analysing the parameters of the electric drive, e.g. current or power consumption

Abstract

A method and apparatus are provided for controlling the operation of a pump, featuring steps of sensing a no water or dead head condition of the flow of the medium in the pump, and dynamically reducing the set-point of the pressure for monitoring the flow of the medium. In operation, a no water operating condition is sensed based on some combination of the magnitude of the motor power consumption, the system pressure, the motor speed, or the flow. The test for the no water operating condition may include the following three conditions: whether the magnitude of the motor power consumption is below full load, the system pressure is below a desired operating point, and the motor-speed is at full speed. The test for the no water operating condition may also include the step of lowering the pump/motor speed and checking if the system pressure drops. If the system pressure drops, then the pump will continue to run, while if the system pressure does not drop, then no flow is detected and the pump is turned off.

Claims

1. A method for controlling the operation of a pump and motor in a pumping system, comprising the steps of:

responding to one or more signals containing information about the motor power consumption, motor speed and system pressure of the pump and motor;

sensing a no water or dead head condition of the flow of the medium in the pump; and

dynamically reducing a set-point of the pressure for monitoring the flow of the medium.

2. A method according to claim 1, wherein a no water operating condition is sensed based on some combination of the magnitude of the motor power consumption, the motor speed, the system pressure, or the flow.

3. A method according to claim 2, wherein the test for the no water operating condition includes the following three conditions:

whether the magnitude of the motor power consumption is below full load, the motor speed is at full speed, and the system pressure is below a desired operating point.

4. A method according to claim 3, wherein the test for the no water operating condition also includes lowering the pump/motor speed and checking if the system pressure drops.

5. A method according to claim 4, wherein if the system pressure drops, then flow is detected and the pump and motor will continue to run.

6. A method according to claim 4, wherein if the system pressure does not drop, then no flow is detected and the pump and motor are turned off.

7. A method according to claim 1, wherein the method comprises providing a feedback signal from a pressure sensor to a controller containing information about the system pressure.

22. A method according to claim 1, wherein the pump and motor includes a centrifugal pump.

8. A pumping system having a controller for controlling the operation of a pump, the controller responding to one or more signals containing information about the motor power consumption, motor speed and system pressure of the pump and motor;

sensing a no water or dead head condition of the flow of the medium in the pump; and

dynamically reducing the set-point of the pressure for monitoring the flow of the medium in response to the no water or dead head condition.

9. A pumping system according to claim 8, wherein a no water operating condition is sensed based on some combination of the magnitude of the motor power consumption, the motor speed, the system pressure, or the flow.

10. A pumping system according to claim 9, wherein the test for the no water operating condition includes the following three conditions:

whether the motor power consumption is below full load, the motor is at full speed, and the pumping system pressure is below a desired operating point.

11. A pumping system according to claim 10, wherein the test for the no water operating condition also includes lowering the pump/motor speed and checking if the system pressure drops.

12. A pumping system according to claim 11, wherein if the system pressure drops, then the pump and motor will continue to run.

13. A pumping system according to claim 12, wherein if the system pressure does not drop, then the pump and motor are turned off.

14. A pumping system according to claim 8, wherein the controller receives a feedback signal from a pressure sensor containing information about the system pressure.

23. A pumping system according to claim 8, wherein the pump and motor includes a centrifugal pump.

15. A controller for controlling the operation of a pump and motor in a pumping system, the controller responding to one or more signals containing information about the motor power consumption, motor speed and system pressure;

sensing a no water or dead head condition of the flow of a medium in the pump; and

dynamically reducing the set-point of the pressure for monitoring the flow of the medium in response to the no water or dead head condition.

16. A controller according to claim 15, wherein a no water operating condition is sensed based on some combination of the magnitude of the motor power consumption, the motor speed, the system pressure, and/or the flow.

17. A controller according to claim 16, wherein the test for the no water operating condition includes the following three conditions:

whether the magnitude of the motor power consumption is below full load, the motor speed is at full speed, and the system pressure is below a desired operating point.

18. A controller according to claim 17, wherein the test for the no water operating condition also includes lowering the pump/motor speed and checking if the system pressure drops.

19. A controller according to claim 18, wherein if the system pressure drops, then the pump and motor will continue to run.

20. A controller according to claim 19, wherein if the system pressure does not drop, then no flow is detected and the pump and motor are turned off.

21. A controller according to claim 15, wherein the controller receives a feedback signal from a pressure sensor containing information about the system pressure.

24. A controller according to claim 15, wherein the pump and motor includes a centrifugal pump.