Abstract: A slide for use in a single screw compressor is disclosed. The screw compressor is arranged to vent the flutes of its main rotor at all times, without having to provide a check valve in the discharge port of the main rotor casing. An additional outlet port in the casing vents gas from the discharge ends of the flutes into the body of the slide instead of to the discharge port. The vented gas is guided to an exit port of the slide, from where it can reach either the discharge port or the bypass port of the casing at all times during use of the compressor and under all loading conditions. The design of the disclosed slide further allows the use of an offset discharge port in the casing, in relation to the main rotor.

Abstract: A single screw compressor is arranged to vent the flutes of its main rotor at all times, without having to provide a check valve in the discharge port of the main rotor casing. An additional outlet port in the casing vents gas from the discharge ends of the flutes into the body of a slide instead of to the discharge port. The vented gas is guided to an exit port of the slide, from where it can reach either the discharge port or the bypass port of the casing at all times during use of the compressor and under all loading conditions. The design of the slide further allows the use of an offset •? discharge port in the casing, in relation to the main rotor. This means that pressure acting through the discharge port in use of the compressor tends to press the slide against another structure than the main rotor, for instance a bearing housing, giving better support to the slide. The slide also provides an improved oil delivery arrangement.

Abstract: A valve comprises a housing (1) having an inlet (4) and an outlet (5), and a pressure sensing port (8). A piston (6) slides in a part (3) of the housing (1) in response to a difference between a first fluid pressure at the pressure sensing port on the one side of the piston, and a second fluid pressure at the inlet and/or outlet on the other side of the piston (6). A valve member (7) carried by the piston is operable thereby to close the inlet (4) when said second fluid pressure is less than a value sufficiently greater than said first fluid pressure. The valve member (7) is movable with respect to the piston (6) to facilitate closing of the inlet (4), in response to a fluid flow from the housing (1) to the inlet (4), when the piston is not acting to close the inlet.