Fremgangsmåte og ventilinnretning for motvirkning av skadelige trykkpulser i et hydraulisk system

摘要

A method and a valve apparatus for counteracting harmful pressure pulses caused by rapid retardation of a liquid in a hydraulic system comprising a pump for the supply of liquid to a conduit stretch containing a non-liquid-filled volume. The valve apparatus comprises a main valve having an inlet connected to a reservoir for pressurised gas, a first valve chamber connected in use to said volume, and a regulating unit for controlling the supply of pressurised gas to the first chamber. The regulating unit comprises a first device arranged to open for the supply of pressurised gas via the main valve to the first chamber when the pressure therein sinks below an activating valve, and thereafter to maintain the pressure in the chamber at a desired value, a second device causing an increased supply of pressurised gas to the first chamber when the pressure therein rises after having fallen to the activiating pressure, and a third device causing closing of the main valve and therewith shutting-off of the gas flow to the first chamber when the pressure therein has risen to a closing value.