Method for optimizing valve position and pump speed in a PID control valve system without the use of external signals

• US 20070212230A1
• Filed: 02/09/2007
• Published: 09/13/2007
• Est. Priority Date: 03/08/2006
• Status: Active Grant

• Current Assignee: ITT Manufacturing Enterprises LLC (ITT, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Stavale, Anthony, Verdehem, Brian
• Granted Patent: US 7,925,385 B2
• Time in Patent Office: Days
• US Class Current: 417/42
• CPC Class Codes: F04D 15/0022 throttling valves or valves varying the pump inlet opening or the outlet opening
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0088 Testing machines

Abstract

The present invention provides an algorithm that utilizes flow reference data which can be mathematically determined as a function of various pump and motor parameters such as speed, torque or power or from calibrated flow curves stored in an evaluation device, or from an external flow reference such as a flowmeter. Once the PID control valve has reached its steady state condition a calculated flow value is captured and compared to the current flow value obtained after the variable frequency drive has decreased in frequency (speed). The valve position is optimized just prior to the speed threshold where the flow condition of the algorithm is no longer true.

Claims

1. A controller comprising:

one or more modules configured for determining flow reference data as a function of various pump and motor parameters such as speed, torque or power or from calibrated flow curves stored in an evaluation device, or from an external flow reference such as a flowmeter; and

one or more modules configured for utilizing the flow reference data in order to control a centrifugal pump, centrifugal blower, centrifugal mixer or centrifugal compressor in a PID control valve system.

2. A controller according to claim 1, wherein, once a PID control valve has reached its steady state normal condition, a calculated flow value is captured and compared to the current flow value obtained after the variable frequency drive has decreased in frequency (speed).

3. A controller according to claim 1, wherein the valve position is optimized just prior to the speed threshold where the flow condition of the algorithm is no longer true.

4. A controller according to claim 1, wherein the valve position is optimized just prior to reaching minimum speed if the flow condition remains true.

5. A controller according to claim 1, wherein for pressure control applications the valve position is optimized if the current flow is within 90-110% of the pump best efficiency flow at current speed.

6. A controller according to claim 1, wherein a final check is made for a wide open control valve condition by increasing pump speed a set amount and comparing the current flow value to a saved flow value, and if there is no increase in flow the valve position is optimized.

7. A controller according to claim 1, wherein if the controller has already reached its optimized state, and if either the actual motor torque increases by 5% or greater, or the actual flow increases by 5% or greater for longer than the delay period, the valve optimization process is restarted at maximum speed.

8. A controller according to claim 1, wherein if the controller has already reached its optimized state, and if either the actual motor torque decreases by 5% or more, or the actual flow decreases by 5% or more, the valve optimization process restarts at the current operating point.

9. A controller according to claim 1, wherein a secondary user selectable wide open valve check is made if a change in actual motor torque is 2% or more but less than 5% of the optimized state for the response delay period, and if this condition is true and the actual flow is greater than the optimized flow value after a speed increment change, the optimization process is restarted at maximum speed.

10. A controller according to claim 2, wherein the valve position is optimized just prior to the speed threshold where the flow condition of the algorithm is no longer true.

11. A controller according to claim 2, wherein the valve position is optimized just prior to reaching minimum speed if the flow condition remains true.

12. A controller according to claim 2, wherein for pressure control applications the valve position is optimized if the current flow is within 90-110% of the pump best efficiency flow at current speed.

13. A controller according to claim 2, wherein a final check is made for a wide open control valve condition by increasing pump speed a set amount and comparing the current flow value to a saved flow value, and if there is no increase in flow the valve position is optimized.

14. A controller according to claim 2, wherein if the controller has already reached its optimized state, and if either the actual motor torque increases by 5% or greater, or the actual flow increases by 5% or greater for longer than the delay period, the valve optimization process is restarted at maximum speed.

15. A controller according to claim 2, wherein if the controller has already reached its optimized state, and if either the actual motor torque decreases by 5% or more, or the actual flow decreases by 5% or more, the valve optimization process restarts at the current operating point.

16. A controller according to claim 2, wherein a secondary user selectable wide open valve check is made if a change in actual motor torque is 2% or more but less than 5% of the optimized state for the response delay period, and if this condition is true and the actual flow is greater than the optimized flow value after a speed increment change, the optimization process is restarted at maximum speed.

17. A method comprising:

determining flow reference data as a function of various pump and motor parameters such as speed, torque or power or from calibrated flow curves stored in an evaluation device, or from an external flow reference such as a flowmeter; and

utilizing the flow reference data in order to control a centrifugal pump centrifugal blower, centrifugal mixer or centrifugal compressor in a PID control valve system.

18. A method according to claim 17, wherein, once a PID control valve has reached its steady state normal condition, a calculated flow value is captured and compared to the current flow value obtained after the variable frequency drive has decreased in frequency (speed)

19. A method according to claim 17, wherein the valve position is optimized just prior to the speed threshold where the flow condition of the algorithm is no longer true.

20. A method according to claim 17, wherein the valve position is optimized just prior to reaching minimum speed if the flow condition remains true.

21. A method according to claim 17, wherein for pressure control applications the valve position is optimized if the current flow is within 90-110% of the pump best efficiency flow at current speed.

22. A method according to claim 17, wherein a final check is made for a wide open control valve condition by increasing pump speed a set amount and comparing the current flow value to a saved flow value, and if there is no increase in flow the valve position is optimized.

23. A method according to claim 17, wherein if the controller has already reached its optimized state, and if either the actual motor torque increases by 5% or greater, or the actual flow increases by 5% or greater for longer than the delay period, the valve optimization process is restarted at maximum speed.

24. A method according to claim 17, if the controller has already reached its optimized state, and if either the actual motor torque decreases by 5% or more, or the actual flow decreases by 5% or more, the valve optimization process restarts at the current operating point.

25. A method according to claim 17, wherein a secondary user selectable wide open valve check is made if a change in actual motor torque is 2% or more but less than 5% of the optimized state for the response delay period, and if this condition is true and the actual flow is greater than the optimized flow value after a speed increment change, the optimization process is restarted at maximum speed.

26. A method according to claim 18, wherein the valve position is optimized just prior to the speed threshold where the flow condition of the algorithm is no longer true.

27. A method according to claim 18, wherein the valve position is optimized just prior to reaching minimum speed if the flow condition remains true.

28. A method according to claim 18, wherein for pressure control applications the valve position is optimized if the current flow is within 90-110% of the pump best efficiency flow at current speed.

29. A method according to claim 18, wherein a final check is made for a wide open control valve condition by increasing pump speed a set amount and comparing the current flow value to a saved flow value, and if there is no increase in flow the valve position is optimized.

30. A method according to claim 18, if the controller has already reached its optimized state, and if either the actual motor torque increases by 5% or greater, or the actual flow increases by 5% or greater for longer than the delay period, the valve optimization process is restarted at maximum speed.

31. A method according to claim 18, if the controller has already reached its optimized state, and if either the actual motor torque decreases by 5% or more, or the actual flow decreases by 5% or more, the valve optimization process restarts at the current operating point.

32. A method according to claim 18, wherein a secondary user selectable wide open valve check is made if a change in actual motor torque is 2% or more but less than 5% of the optimized state for the response delay period, and if this condition is true and the actual flow is greater than the optimized flow value after a speed increment change, the optimization process is restarted at maximum speed.