Acf Industries, Incorporated

Joy Manufacturing Company

Bruce P Noble

Tri C Le

Brett A Babbitt

An expanding gate valve (10) provided with a piston type pneumatic powered actuator (40) for opening and closing the valve wherein the actuator piston (54) is adapted to be driven by fluid pressure in one direction to operate the valve but is returned by spring means (63, 64) when the pressure is removed. The actuator includes a hydraulic choke means (71) comprising a hydraulic piston (80) and cylinder (72) wherein the hydraulic piston is fixed to the actuator stem (23) and is provided with an orifice (89) which imposes a constant velocity control on the actuator stroke by producing a throttling effect on the hydraulic fluid moving from one side of the hydraulic piston to the other. The hydraulic cylinder (72) is filled with a fluid which maintains substantially uniform viscosity in the range of minus 40.degree. Centigrade to 204.degree. Centigrade whereby the valve is adapted for consistent operation during rapid cycling conditions. The actuator housing (41, 42) is a sealed unit with the exception of a single opening (69) which exposes one side of the actuator piston (54) to atmospheric pressure but which may serve as an inlet for pressurized fluid to convert the actuator to a double acting piston actuator when the spring force for returning the actuator piston is inadequate.

Expanding gate valve with fluid-powered actuator

A pressure energizable sealing connection for establishing a bore seal between first and second coaxially aligned and connected members (22, 10) having opposed internal recesses forming seat pockets at their adjoining ends. The invention comprises a sealing ring (40) having annular end surfaces (56, 54) and an internal diameter which corresponds to the bores of the coaxially aligned members (22, 10), the connection of which is to be sealed. The ring (40) is provided with a pair of circumferential projections (67, 68) separated by a groove (69) therebetween and each having an external surface of arcuate configuration. At their adjoining ends (25, 26) the opposed seat pockets of the adjoining members (22, 10) provide annular cylindrical walls (41, 42) for sealing engagement with the annular projections (67, 68) of the sealing ring (40). The external diameter of the ring (40) is slightly larger than the diameters of the seat pockets so that the resulting interference fit between the ring (40) and the cylindrical walls (41, 42) of the seat pockets provides an initial seal between the projections of the ring (40) and the coaxially connected members (22, 10). The axial dimension of the ring equals the sum of the axial dimensions of the seat pockets so there is no axial compression of the ring by the connected members (22, 10). Fluid pressurization of the coaxially adjoined members results in pressure energization of the sealing ring so that any increase in pressure internally of the connected members results in a greater radial compression of the sealing ring and correspondingly greater sealing forces.

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Houston, TX, United States of America

Bruce P Noble