Claims
- 1. A method for predicting a remaining service life of a filter element, said filter element having an inlet side, an outlet side and a membrane separating said inlet side from said outlet side such that there exists a differential pressure across said membrane when said filter element is in service, the method comprising:measuring a first pressure on the inlet side with a first micro-electro-mechanical systems (MEMS) pressure sensor disposed proximate said inlet side; measuring a second pressure on the outlet side with a second MEMS pressure sensor disposed proximate said outlet side; calculating the differential pressure across said membrane based on the measurements taken with said first and second MEMS pressure sensors; correlating said differential pressure to an amount of contaminant removed by said filter element; calculating a remaining contaminant capacity of the filter element; calculating a rate of contaminant removal; and determining the remaining service life of said filter element.
- 2. The method of claim 1, wherein calculating a rate of contaminant removal includes measuring a fluid volume feed rate.
- 3. The method of claim 1, wherein each of said MEMS sensors is configured to communicate its respective measurement to at least one of a processor and a data processing device.
- 4. The method of claim 3, wherein said MEMS sensors are configured to communicate said measurements in real time.
- 5. The method of claim 1, wherein said first and second MEMS sensors are in contact with a fluid being filtered through said filter element.
- 6. The method of claim 5, wherein each of said MEMS sensors is flush with said fluid.
- 7. The method of claim 5, each said MEMS pressure sensor comprising:a pressure reference chamber; a pressure sensor diaphragm, said diaphragm separating said fluid from said pressure reference chamber; and a conductive element coupled to said diaphragm, said conductive element having a variable resistance that depends on an amount of deflection of said conductive element.
- 8. The method of claim 7, wherein said conductive element is configured to deflect when a pressure difference exists between said fluid and said pressure reference chamber thereby allowing said pressure difference to be measured as a function of the change in said resistance of said conductive element.
- 9. The method of claim 7, each said MEMS pressure sensor further including a conductive lead that is configured to electrically couple said conductive element to a bridge circuit having a reference resistance.
- 10. The method of claim 7, wherein said conductive element is a piezoelectric element.
- 11. The method of claim 7, wherein said conductive element is affixed to a surface of said diaphragm.
- 12. The method of claim 7, wherein said conductive element is embedded within said diaphragm.
- 13. A method for predicting a remaining service life of a filter element, said filter element having an inlet side, an outlet side and a membrane separating said inlet side from said outlet side such that there exists a pressure difference across said membrane when said filter element is in service, the method comprising:measuring a first pressure on the inlet side with a first micro-electro-mechanical systems (MEMS) pressure sensor disposed proximate said inlet side; measuring a second pressure on the outlet side with a second MEMS pressure sensor disposed proximate said outlet side; calculating the pressure difference across said membrane based on the measurements taken with said first and second MEMS pressure sensors; calculating a rate of change of the pressure difference; and determining the remaining service life of said filter element based on a differential pressure limit.
- 14. The method of claim 13, wherein each of said MEMS sensors is configured to communicate its respective measurement to at least one of a processor and a data processing device.
- 15. The method of claim 14, wherein said MEMS sensors are configured to communicate said measurements in real time.
- 16. The method of claim 13, wherein said first and second MEMS sensors are in contact with a fluid being filtered through said filter element.
- 17. The method of claim 16, wherein each of said MEMS sensors is flush with said fluid.
- 18. The method of claim 16, each said MEMS pressure sensor comprising:a pressure reference chamber; a pressure sensor diaphragm, said diaphragm separating said fluid from said pressure reference chamber; and a conductive element coupled to said diaphragm, said conductive element having a variable resistance that depends on an amount of deflection of said conductive element.
- 19. The method of claim 18, wherein said conductive element is configured to deflect when a pressure difference exists between said fluid and said pressure reference chamber thereby allowing said pressure difference to be measured as a function of the change in said resistance of said conductive element.
- 20. The method of claim 18, each said MEMS pressure sensor further including a conductive lead that is configured to electrically couple said conductive element to a bridge circuit having a reference resistance.
- 21. The method of claim 18, wherein said conductive element is a piezoelectric element.
- 22. The method of claim 18, wherein said conductive element is affixed to a surface of said diaphragm.
- 23. The method of claim 18, wherein said conductive element is embedded within said diaphragm.
- 24. A method for predicting a remaining service life of a filter element, said filter element having an inlet side, an outlet side and a membrane separating said inlet side from said outlet side such that there exists a differential pressure across said membrane when said filter element is in service, the method comprising:measuring said differential pressure across said membrane with a micro-electro-mechanical systems (MEMS) differential pressure sensor; correlating said differential pressure to an amount of contaminant removed by said filter element; calculating a remaining contaminant capacity of the filter element; calculating a rate of contaminant removal; and determining the remaining service life of said filter element.
- 25. The method of claim 24, wherein said MEMS sensor is in contact with a fluid being filtered through said filter element.
- 26. The method of claim 25, wherein said MEMS sensor is flush with said fluid.
- 27. The method of claim 24, wherein said MEMS sensor is configured to communicate its measurement to at least one of a processor and a data processing device.
- 28. The method of claim 27, wherein said MEMS sensor is configured to communicate said measurement in real time.
- 29. A method for predicting a remaining service life of a filter element, said filter element having an inlet side, an outlet side and a membrane separating said inlet side from said outlet side such that there exists a differential pressure across said membrane when said filter element is in service, the method comprising:measuring said differential pressure across said membrane with a micro-electro-mechanical systems (MEMS) differential pressure sensor; calculating a rate of change of said differential pressure; and determining the remaining service life of said filter element based on a differential pressure limit.
- 30. The method of claim 29, wherein said MEMS sensor is in contact with a fluid being filtered through said filter element.
- 31. The method of claim 30, wherein said MEMS sensor is flush with said fluid.
- 32. The method of claim 29, wherein said MEMS sensor is configured to communicate its measurement to at least one of a processor and a data processing device.
- 33. The method of claim 32, wherein said MEMS sensor is configured to communicate said measurement in real time.
Parent Case Info
This application is a DIV of U.S. patent application Ser. No. 09/721,499, filed on Nov. 22, 2000, now U.S. Pat. No. 6,471,853.
US Referenced Citations (18)
Non-Patent Literature Citations (2)
Entry |
Aerospace Engineering, Jan./Feb. 1994, “Hydraulic System Diagnostic Sensors”, pp. 43-48. |
Http://www.transtronics.com/zprimer.htm; Pressure Transducer Basics: A Primer, Nov. 20, 2000, pp. 1 of 13. |