Claims
- 1. Method for monitoring the condition of a valve and valve operator to signal a need for maintenance of the valve or valve operator, said method comprising the steps of:
- imposing a thrust load in the valve operator during a calibration period;
- measuring the thrust load imposed in the valve operator;
- measuring a power parameter of the valve operator during imposition of the thrust load;
- calibrating thrust load to the power parameter;
- ending the imposing of thrust load in the valve operator during the calibration period;
- placing the valve and valve operator in use;
- measuring the power parameter of the valve operator during valve-in-use generation of thrust load in the valve operator; and
- correlating the power parameter measured during imposition of the load with the power parameter measured during valve-in-use to provide an indication of thrust load developing in the valve operator during valve-in-use.
- 2. Method of claim 1, wherein the step of imposing a load in the valve operator comprises the steps of:
- engaging the valve stem of the valve operator; and
- resisting movement of the valve stem.
- 3. Method of claim 1, wherein the step of measuring a power parameter comprises the step of measuring the operator motor power.
- 4. Method of claim 1, wherein the step of measuring a power parameter comprises the step of measuring the power factor associated with the operator motor.
- 5. Method of claim 1, wherein the steps of measuring a power parameter and monitoring the power parameter are accomplished at a terminal located at a location removed in space from said valve operator.
Parent Case Info
This application is a continuation of patent application Ser. No. 848,451 filed Apr. 4, 1986, now U.S. Pat. No. 4,831,873.
US Referenced Citations (7)
Foreign Referenced Citations (1)
Number |
Date |
Country |
431464 |
Jul 1975 |
SUX |
Non-Patent Literature Citations (4)
Entry |
Square D--Class 8430 Type G Load Converter Relays--Instruction Sheet 63080-003-01, Nov. 1983. |
Square D--Product Data--Bulletin M-629 Load Monitoring for Three Phase Induction Motors-Apr. 1984. |
Square D--Product News--Control Products--Load Detector and Load Converter Relays Type V and G-1C-277, Class 8430, Nov. 1983. |
Morlan & Associates, Inc. Information Sheet on AC Power Factor, and Watt Transducer PCII Series (date unknown). |
Continuations (1)
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Number |
Date |
Country |
Parent |
848451 |
Apr 1986 |
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