Method of monitoring the condition of a motor operated valve system
First Claim
1. Method of identifying, during valve-in-use operation, an unacceptable degredation of the operating condition of a motor operated valve system, which system is comprised of a valve driven by a valve stem which is driven by a valve actuator which is driven by an electric motor, said method comprising the steps of:
- establishing, for a specific valve system, a value (referred to as "BASE") representative of actuator output torque during baseline running conditions, baseline running conditions being defined as as near to normal, non-degraded running condition as possible for the valve;
establishing, for the valve system, a value (referred to as "MAX") representative of the maximum actuator output torque to be allowed during running condition, based on a predefined, allowed degraded stem factor;
determining the maximum allowed percentage increase in the actuator output torque from BASE during running condition by the formula;
##EQU3## wherein "safety factor" is a number greater than or equal to one;
establishing, for the valve system, a value of a selected power related parameter of the motor during baseline running conditions;
determining a warning value of the selected power related parameter as equal to the warning level percentage of the established baseline value of the power related parameter;
monitoring the selected power related parameter associated with the valve system during valve-in-use conditions; and
evaluating changes in the value of the selected power related parameter over the monitoring period,whereby, an increase in monitored power related parameter value indicates a potential problem and an increase in the monitored parameter to the warning value indicates operational readiness may be compromised.
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Accused Products
Abstract
A method of evaluating degradations throughout a MOV (i.e. motor operated valve) by establishing specific interrelationships between a power related parameter from the MOV motor (being, for an AC motor, preferably the motor load; and being, for a DC motor, preferably motor torque or motor torque factor) and actuator torque; then utilizing the established interrelationships to further establish a given percent change in the power related parameter as a warning point; and, then, trending the power related parameter during valve-in-use operation of the valve system to evaluate the condition of the valve system.
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Citations
17 Claims
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1. Method of identifying, during valve-in-use operation, an unacceptable degredation of the operating condition of a motor operated valve system, which system is comprised of a valve driven by a valve stem which is driven by a valve actuator which is driven by an electric motor, said method comprising the steps of:
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establishing, for a specific valve system, a value (referred to as "BASE") representative of actuator output torque during baseline running conditions, baseline running conditions being defined as as near to normal, non-degraded running condition as possible for the valve; establishing, for the valve system, a value (referred to as "MAX") representative of the maximum actuator output torque to be allowed during running condition, based on a predefined, allowed degraded stem factor; determining the maximum allowed percentage increase in the actuator output torque from BASE during running condition by the formula;
##EQU3## wherein "safety factor" is a number greater than or equal to one;
establishing, for the valve system, a value of a selected power related parameter of the motor during baseline running conditions;determining a warning value of the selected power related parameter as equal to the warning level percentage of the established baseline value of the power related parameter; monitoring the selected power related parameter associated with the valve system during valve-in-use conditions; and evaluating changes in the value of the selected power related parameter over the monitoring period, whereby, an increase in monitored power related parameter value indicates a potential problem and an increase in the monitored parameter to the warning value indicates operational readiness may be compromised. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification