Method and system for determining pump cavitation and estimating degradation in mechanical seals therefrom
First Claim
1. A method for determining cavitation in a pump having a known non-cavitating dynamic pressure measure, comprising the steps of:
- determining a cavitation alarm dynamic pressure as a known percentage of said non-cavitating pressure measure;
measuring dynamic pressure in said pump; and
comparing said measured dynamic pressure to said cavitation alarm dynamic pressure; and
outputting an indicator when said measured dynamic pressure is less than said cavitation alarm dynamic pressure.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and system for determining pump cavitation is disclosed. In accordance with the principle of the invention, changes in dynamic fluid pressure within a pump are monitored and compared to a determined cavitation alarm pressure. The determined cavitation pressure is determined as a known percentage of a known non-cavitation pressure. Fluid cavitation is determined when the change in dynamic fluid pressure falls below the determined cavitation alarm pressure. In a further aspect of the invention, a remaining mechanical seal operational life can be determined by maintaining a total time of fluid cavitation and reducing the expected life by the known operational time of the pump and the time the pump is in cavitation.
16 Citations
33 Claims
-
1. A method for determining cavitation in a pump having a known non-cavitating dynamic pressure measure, comprising the steps of:
-
determining a cavitation alarm dynamic pressure as a known percentage of said non-cavitating pressure measure;
measuring dynamic pressure in said pump; and
comparing said measured dynamic pressure to said cavitation alarm dynamic pressure; and
outputting an indicator when said measured dynamic pressure is less than said cavitation alarm dynamic pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
determining a time duration of the occurrence of cavitation;
determining a seal degradation time in relation to said time duration and a seal degradation factor;
determining a remaining seal life by removing said seal degradation time from a known seal life measure.
-
-
3. The method as recited in claim 1 wherein said measured dynamic pressure is measured as a root mean square measure.
-
4. The method as recited in claim 1 wherein said known percentage of non-cavitation pressure is in the range of 10 to 90 percent.
-
5. The method as recited in claim 4 wherein said known percentage is 50 percent.
-
6. The method as recited in claim 1 wherein in the step of outputting an indicator includes:
maintaining a known logic level.
-
7. The method as recited in claim 1 wherein in the step of outputting an indicator further includes the step of:
- outputting a second indicator when said measured pressure is greater than said cavitation alarm dynamic pressure.
-
8. The method as recited in claim 6 wherein a time duration is measured for the duration of said indicator.
-
9. The method as recited in claim 7 wherein a time duration is measured between the occurrence of said indicator and said second indicator.
-
10. The method as recited in claim 2 wherein said known seal life measure corresponds to a known expected seal life reduced by a known operational time.
-
11. A system for determining cavitation in a pump having a known non-cavitating dynamic pressure measure, comprising:
-
at least one sensor, in communication with said pump, operative to measure dynamic pressure in said pump; and
a processor, in communication with said at least one sensor, operative to;
compare said measured dynamic pressure in said pump to a cavitation alarm dynamic pressure, wherein said cavitation alarm dynamic pressure is a known percentage of said non-cavitating pressure measure; and
output an indicator when said measured dynamic pressure is less than said cavitation alarm dynamic pressure. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
determine a time duration of the occurrence of cavitation;
determine a seal degradation time in relation to said time duration and a seal degradation factor;
determine a remaining seal life by removing said seal degradation time from a known seal life measure.
-
-
13. The system as recited in claim 11 wherein said measured dynamic pressure is measured as a root mean square measure.
-
14. The system as recited in claim 11 wherein said known percentage of non-cavitation pressure is in the range of 10 to 90 percent.
-
15. The system as recited in claim 14 wherein said known percentage is 50 percent.
-
16. The system as recited in claim 11 wherein said outputted indicator is maintained at a known logic level.
-
17. The system as recited in claim 11 wherein said outputted indicator includes outputting a second indicator when said measured pressure is greater than said cavitation alarm dynamic pressure.
-
18. The system as recited in claim 12 wherein said time duration is measured for the duration of said indicator.
-
19. The system as recited in claim 17 wherein a time duration is measured between the occurrence of said indicator and said second indicator.
-
20. The system as recited in claim 12 wherein said known seal life measure corresponds to a known expected seal life reduced by an operational time.
-
21. The system as recited in claim 11 wherein at least one of said at least one sensor is installed in a mechanical seal unit of said pump.
-
22. The system as recited in claim 11 wherein at least one of said at least one sensor is installed in a suction nozzle area of said pump.
-
23. A method for determining seal life degradation in a pump having a known non-cavitating dynamic pressure measure, comprising the steps of:
-
determining a cavitation alarm dynamic pressure as a known percentage of said non-cavitating pressure measure;
measuring dynamic pressure in said pump;
comparing said measured dynamic pressure to said cavitation alarm dynamic pressure;
outputting an indicator when said measured dynamic pressure is less than said cavitation alarm dynamic pressure;
determining a time duration of the occurrence of cavitation;
determining a seal degradation time in relation to said time duration and a seal degradation factor; and
determining a remaining seal life by removing said seal degradation time from a known seal life measure. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
maintaining a known logic level.
-
-
28. The method as recited in claim 23 wherein in the step of outputting an indicator further includes the step of:
outputting a second indicator when said measured pressure is greater than said cavitation alarm dynamic pressure.
-
29. The method as recited in claim 23 wherein said time duration is measured for the duration of said indicator.
-
30. The method as recited in claim 28 wherein said time duration is measured between the occurrence of said indicator and said second indicator.
-
31. The method as recited in claim 23 wherein said known seal life measure corresponds to a known expected seal life reduced by a known operational time.
-
32. A system for determining cavitation in a pump having a known non-cavitating dynamic pressure measure, comprising:
-
at least one sensor, in communication with said pump, operative to measure dynamic pressure in said pump; and
a processor, in communication with said at least one sensor, operative to;
compare said measured dynamic pressure in said pump to a known percentage of said non-cavitating measure; and
determine a remaining seal life based in part upon said comparison.
-
-
33. A method for determining seal life degradation in a pump having a known non-cavitating dynamic pressure measure, comprising the steps of:
-
measuring dynamic pressure in said pump;
comparing said measured dynamic pressure to a known percentage of said non-cavitating pressure measure; and
determining remaining seal life based in part upon said comparing step.
-
Specification