Abstract: A close-off valve for suction pipes to establish communication between a source of pressure and a consumer of pressure, such as a hydraulic pump. The valve makes it possible to disconnect the consumer in a simple and reliable manner, that is without leakage of the pressure, in addition to which it allows a liquid, such as oil, in certain quantities to flow through the valve above the valve disc, when the latter assumes the position in which it closes the outlet of the valve. For this purpose the valve comprises a solenoid valve which controls a flow of pressurized air to the valve housing in order to actuate the valve disc closing off said communication. In addition, the valve is arranged with through-passage means above said disc in order to allow passage-through of a certain amount of liquid, when the valve disc is in its closing position.