Abstract: 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.

Abstract: A gas regulating valve, especially for use in breathing valves for diver masks and the like. The valve comprises a sleeve-shaped housing (1) having an inlet chamber (I) and an outlet chamber (II), a main valve body (2) cooperating with a seat (3) separating the inlet chamber (I) from the outlet chamber (II), a piston (12) or the like separating the outlet chamber (II) from a servo chamber (III), and a control valve (5,6) arranged to be opened and closed by the main valve body (2). The control valve (5,6) causes a controlled gas flow to the servo chamber (III), which entails that the main valve body (II) is forced to move such that the seat (6) of the control valve at all times rests sealingly against the valve body (5) of the control valve.