Abnormality detection/suppression system for a valve apparatus

摘要

Provision of an abnormality detection and suppression system for a valve apparatus, which is capable of detecting abnormal states such as leakage through valve seats or a gland/packing assembly and coping with the abnormality while ensuring protection for the valve apparatus by controlling a driving unit for a valve stem on the basis of information as detected, by means of a vibration sensor, a temperature sensor and a strain sensor are disposed internally of a valve stem 4 at a portion thereof which lies outside of a valve casing of the valve apparatus. When vibration of the valve stem brought abut by leakage through valve seats is detected by the vibration sensor in a fully closed state of the valve apparatus, a valve body thereof is driven further in the valve closing direction by a driving unit 13 controlled by a control unit, both being disposed externally of the valve casing, until the leakage and thus the vibrations disappear while monitoring simultaneously a load applied to the stem by the strain sensor. On the other hand, when a temperature change of the stem is detected by the temperature sensor in the fully open state of the valve apparatus, the control unit decides that the temperature change is due to leakage through a gland/packing assembly 12 of the valve apparatus to thereby control the driving unit so that the stem is driven to move the valve body in the valve opening direction while monitoring simultaneously a load applied to the stem until the change in the temperature is canceled out.