Abstract: A valve of the invention includes a valve body having an inlet, an outlet, and a flow passage connecting the inlet and outlet, the inlet, the outlet and the flow passage being in general axial alignment within the valve body. A valve seat surrounds the flow passage and a valve closure member is movable towards and away from the valve seat to close and open the valve respectively. The valve closure member is a poppet-type closure member axially mounted to a stem. The stem has a plurality of pistons spaced apart along the length thereof, and the valve body has a plurality of cylinders fixed relative thereto, the pistons each being slidable in a respective cylinder. The valve closure member is movable by varying the pressure in the cylinders. Preferably each of the cylinders has an outlet port through a wall thereof which is exposed when the closure member has moved towards or into a fully open position, pressure within said cylinders dissipating through those outlet ports when the outlet ports are exposed.

Abstract: An air supply system and valve is disclosed which provides a reverse pulse of air for cleaning a filter element located in a filter house. A valve is also disclosed for use in the air supply system. The system includes a pressure vessel adapted to contain a volume of compressed air to be used for supplying the reverse pulse, the pressure vessel having a wall with at least one outlet aperture therein. The valve is mounted to the wall around the aperture to control the flow of air from the pressure vessel, the valve means comprising a valve body having an inlet, an outlet and a flow passage connecting the inlet and outlet, the inlet, the outlet and the flow passage generally extending axially through the valve body, a valve seat surrounding the flow passage, and a valve closure member movable towards and away from the valve seat into closed and open positions to thereby close or open the flow passage, and operating means for moving the valve closure member between the closed and open positions.

Abstract: A bladder valve (10) is disclosed which comprises a valve body (12) having an inlet (16), an outlet (14) and a flow passage (17) connecting the inlet (16) and the outlet (14). The bladder valve (10) also includes a valve seat (45) surrounding the flow passage (17) and an inflatable bladder (22) mounted in the flow passage (17) and being connectable to a source of fluid under pressure in use. The bladder (22) is mounted on a bladder support member (34) which provides support for the bladder when in its deflated condition, and through which inflation passages (42) pass for the inflation and deflation of the bladder. The bladder (22) is designed to collapse or deflate rapidly in order to open the valve, enabling the valve to be used in applications such as reverse pulse cleaning of filter elements.

Abstract: An air flow control valve including a valve body having an internal cavity and an inlet and outlet in flow communication with the internal cavity, the axes of the inlet and outlet being aligned at substantially 90° to each other, a valve seat located within the cavity and co-axially aligned with the outlet, the valve seat being located on the distal end of an upstanding tubular pedestal which is formed around the outlet, the internal cavity being configured so as to define an annular space around the pedestal with which the inlet is in flow communication; a flexible generally planar diaphragm mounted above the valve seat, the diaphragm supporting a valve closure member which is adapted to engage the valve seat to close the valve, valve control means for causing the diaphragm to move towards and away from the valve seat to close and open the valve respectiely; and the valve being characterised in that, with the valve oriented with the inlet axis horizontal and the outlet facing downwards, the valve seat is