METHOD FOR CLOSING FLUID PASSAGE, WATER HAMMERLESS VALVE AND WATER HAMMERLESS CLOSING DEVICE

摘要

A fluid passage is emergently-closed in a short time without causing a water hammer by an extremely simple device and operation. A water hammerless closing device includes an actuator operated valve provided in a fluid passage, an electro-pneumatic conversion device for supplying a 2-step actuator operating pressure Pa to an actuator operated-type valve, a vibration sensor removably secured to the pipe passage on the upstream side of the actuator operated-type valve, and a tuning box receiving a vibration detection signal Pr from the vibration sensor and delivering a control signal Sc to the electro-pneumatic conversion device for controlling the step operating pressure Ps'of the 2-step actuator operating pressure Pa so that, with the control signal Sc being regulated, the electro-pneumatic conversion device outputs the 2-step actuator operating pressure Pa with the step operating pressure Ps'capable of bringing the vibration detection signal Pr substantially to zero.