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Title: Apparatus and method for non-invasive diagnosis and control of motor operated valve condition

An apparatus compares the torque from an MOV motor with the valve displacement, and from the comparison assesses MOV operating condition. A transducer measures the vibration of the housing of an MOV. The vibrations are due to the motions of the rotating elements within the housing, which motions are directly related to the motion of the valve relative to its seat. Signal processing apparatus analyzes the vibrations to recover the rotations of the rotating elements and thus the motion of the valve plug. Lost motion can also be determined (if a lost motion connection exists) by demodulating the vibration signal and thus taking into account also the lost motion. Simultaneously, the forces applied to the valve are estimated by estimating the torque between the stator and the rotor of the motor. Such torque can be estimated from measuring the input current and voltage alone, using a forgetting factor and a correction for the forgetting factor. A signature derived from relating the torque to the valve position can be used to assess the condition of the MOV, by comparing the signature to signatures for MOVs of known conditions. The vibration analysis components generate signals that relate to the position of elementsmore » in the operator. Similarly, the torque estimator estimates the torque output by any type of electric motor, whether or not part of an MOV analysis unit.« less
Inventors:
 [1];  [2];  [3];  [1];  [1];  [4]
  1. (Belmont, MA)
  2. (Seoul, KR)
  3. (Sudbury, MA)
  4. (Helsinki, FI)
Issue Date:
OSTI Identifier:
870785
Assignee:
Massachusetts Institute of Technology (Cambridge, MA) LANL
Patent Number(s):
US 5594175
Contract Number:
W-7405-ENG-36
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM
Country of Publication:
United States
Language:
English
Subject:
apparatus; method; non-invasive; diagnosis; control; motor; operated; valve; condition; compares; torque; mov; displacement; comparison; assesses; operating; transducer; measures; vibration; housing; vibrations; due; motions; rotating; elements; directly; related; motion; relative; seat; signal; processing; analyzes; recover; rotations; plug; lost; determined; connection; exists; demodulating; taking; account; simultaneously; forces; applied; estimated; estimating; stator; rotor; measuring; input; current; voltage; forgetting; factor; correction; signature; derived; relating; position; assess; comparing; signatures; movs; conditions; analysis; components; generate; signals; relate; operator; similarly; estimator; estimates; output; type; electric; unit; analysis unit; directly related; signal processing; electric motor; processing apparatus; forces applied; operating condition; valve plug; operated valve; motor operated; generate signals; vibration signal; torque output; rotating element; signal process; valve position; transducer measures; /73/

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