Regulator valve fault checking method
AssigneeAzbil Corporation
InventorToru Kashima
Life of this patent
Estimating the term…
Abstract
An operating device pressure Po into a regulator valve and a degree of opening X from the regulator valve are sampled. A speed of change vPo (k) of the Po (k) is calculated from the current Po (k) and the previous Po (k −1). A speed of change vX (k) of the X (k) is calculated from the current X (k) and the previous X (k −1). If both vPo (k) and vX (k) are small, then a weighting value w1 (k) is set to 1 (and set to 0 otherwise), where a fault check indicator Fq (i) for each degree-of-opening category i during a fault check evaluation time interval is calculated from the vPo (k) and vX (k) when w1 (k) is 1 and from a linear approximation formula F1 that indicates the steady-state input/output relationships in the regulator valve when operating properly.
Claims10
A regulator valve fault checking method for performing fault checking of a regulator valve regulating the flow of a fluid, comprising the steps of:
- periodically sampling a signal inputted into the regulator valve and, a degree of valve opening outputted from the regulator valve;
- calculating a speed of change of the sampled input signal;
- calculating a speed of change of the sampled degree of valve opening;
- calculating a weighting using the speed of change of the input signal and the speed of change of the degree of valve opening, and a weighting function that has been established in advance;
- and
- fault checking of the regulator valve using the sampled input signal, the sampled degree of valve opening and the calculated weighting,
- wherein the weighting function is a function where the weighting is large when the absolute values of the speed of change of the input signal and the speed of change of the valve opening are in ranges that are less than threshold values,
- wherein the step of performing the fault checking calculates a fault check indicator value, and
- wherein a specific time interval set in advance is used as a fault check evaluating interval, where the input signals and degrees of valve opening for which the weightings are calculated to be no less than a specific value are defined as valid data, and a fault check indicator value for use when performing fault checking of the regulator valve is calculated based on the input signals and degrees of valve opening that have been defined as valid data during the fault check evaluation time interval.
A method to perform fault checking of a regulator valve regulating the flow of a fluid, comprising the steps of:
- periodically sampling, using a processor, a degree of valve opening of the regulator valve;
- calculating, using the processor, a rate of change of the sampled degree of valve opening;
- periodically sampling, using the processor, an input signal sent to the regulator valve;
- calculating, using the processor, a rate of change of the sampled input signal;
- retrieving, from a non-transitory memory, a predetermined weighting function;
- calculating a weighting, using the processor, based on the rate of change of the sampled degree of valve opening, the rate of change of the sampled input signal and the predetermined weighting function;
- and
- fault checking the regulator valve based on the sampled degree of valve opening of the regulator valve, the sampled input signal sent to the regulator valve, and the weighting.
Dependencies are inferred from the claim text.