Patent ID: 7849869
Filing Date: 2010-12-14
Classification: F16K,Y10T

Abstract:
1. A multi-step method for abrupt water hammerless opening of a fluid passage, the method comprising the steps of: (a) providing a fluid passage openable by operation of an actuator operating type valve provided on the fluid passage of a pipe passage, wherein the fluid passage has a nearly constant pressure inside the pipe passage; (b) detecting a vibration detecting signal Pr from vibration of the pipe passage caused by a change of internal pressure of the pipe passage; (c) moving a valve body of the actuator operating type valve from a state of full valve closing in a direction of valve opening to a first degree of valve opening by increasing driving input to an actuator of the actuator operating type valve, wherein the driving input is increased to a first prescribed set value sufficient to prevent a water hammer in the fluid passage, wherein the first prescribed set value is a step pressure setting signal Ps wherein the vibration detecting signal Pr does not exceed a permissible upper limit vibration setting signal Prm; (d) holding the driving input to the actuator at the first set value for a first period of time; and then (e) further increasing the driving input to move the valve body from the first degree of valve opening to a state of full valve opening so the fluid passage is opened without causing a water hammer, and wherein the valve body of the actuator operating type valve is moved from the state of full valve closing to the state of full valve opening in only two steps, or only three steps, or only four steps.