Valve

Abstract

A change in operation time due to a change or the like of a valve actuator with the passage of time is monitored by a valve alone. A valve V includes: a manipulation pressure chamber 52 into which a manipulation pressure for opening and closing the valve V is introduced; a manipulation pressure sensor D that detects a change in manipulation pressure in the manipulation pressure chamber 52; and a magnetic sensor M that detects an internal operation of the valve V corresponding to the change in manipulation pressure. A time from a predetermined time point at which the manipulation pressure changes to a predetermined time point at which an operation corresponding to the change of the manipulation pressure is detected by the magnetic sensor M, is monitored as an operation time of the valve V based on data detected by the magnetic sensor M and the manipulation pressure sensor D.

Dependencies are inferred from the claim text.