Abstract: A device for controlling the flow of a fluid through a conduit from an upstream side of the device to a downstream side of the device. The device includes a valve aperture (30), a cylindrical mounting member (24) on the downstream side of the valve aperture, a valve member (26) on the outside of the cylindrical mounting member that moves reciprocally to open and close the valve aperture, a control volume (44) defined between the cylindrical mounting member and the valve member, an arrangement (8) for introducing a control pressure into the control volume, and a seal (34) between the outer surface of the cylindrical mounting member and the inner surface of the valve member that substantially seals the control volume. The valve member is acted on by the pressure of the upstream side (PI) and the control pressure (P4) so as to be moved by the difference between these pressures.

Abstract: A device (1) for controlling the flow of a fluid through a conduit (3) from an upstream side (8) to a downstream side (10). The device includes a housing (4) having one or more valve apertures (6) through which the flow of fluid is selectively controlled. A valve member (12) is mounted on the housing and arranged to move reciprocally to selectively open and close the one or more valve apertures. A seal (20) is arranged at or beyond a position the valve member reaches when the one or more valve apertures are all closed. The device also includes a resilient member (26) that acts to bias the seal towards the valve member.

Abstract: A device (1) for controlling the flow of fluid through a conduit from an upstream side (3) to a downstream side (5). The device includes a housing (4) with a wall (6) having valve apertures (8) through which the flow of fluid is selectively controlled. A valve member (10) is mounted on one side of the wall of the housing and is arranged to move reciprocally to selectively open and close the valve apertures. A removable insert (12) is mounted on the opposite side of the wall of the housing from the valve member. The removable insert is arranged to cover some of the valve apertures.

Abstract: A device (1) for controlling the flow of a fluid through a conduit (3) from an upstream side (8) to a downstream side (10). The device includes one or more valve apertures (6) through which the flow of fluid is selectively controlled. A valve member (12) is arranged to move reciprocally to selectively open and close the one or more valve apertures. The device includes a stop (18) for arresting the travel of the valve member arranged at or beyond a position the valve member reaches when at least some of the one or more valve apertures are open. The valve member includes an end portion (13) arranged to come into contact with the stop when the valve member reaches or passes the position at which at least some of the one or more valve apertures are open and a body portion (9).