Patent ID: 8047225

Claim:
A device for water hammerless opening of a fluid passage, comprising: (a) a valve comprising a valve body; (b) an actuator disposed to drive the valve body; (c) a vibration sensor removably fixed to a pipe passage on an upstream side of the valve; (d) an electro-pneumatic conversion control device disposed to receive a valve opening/closing command signal input, wherein the electro-pneumatic conversion control device comprises a data storage part, wherein an actuator operating pressure Pa inputted to the actuator is controlled by a control signal Sc stored in advance in the data storage part; and (e) a computation control device comprising a comparison computation circuit, wherein the comparison computation circuit is disposed to receive as input a vibration detecting signal Pr from the vibration sensor, a step pressure setting signal Ps to be supplied to the actuator, a step pressure holding time setting signal Ts, and a permissible upper limit vibration pressure setting signal Prm, and wherein the comparison computation circuit compares the vibration detecting signal Pr and the permissible upper limit vibration pressure setting signal Prm, and the step pressure setting signal is adjusted by the comparison computation circuit so that the control signal Sc is outputted by the comparison computation circuit to the data storage part of the electro-pneumatic conversion control device, wherein the control signal Sc comprises the holding time setting signal Ts and the adjusted step pressure setting signal Ps.