Joy Manufacturing Company

Brett A Babbitt

Tri C Le

Bruce P Noble

A holddown screw 10 which features a shank 23 and contact nose 22 of separate construction. The contact nose 22 is provided with a flat bevelled contact surface 32 of predetermined angle to the axis of the screw selected to correspond to the angle of the camming surface 17a with which it is designed to cooperate. The contact nose is carried on the shank 23 and is adapted for relative rotation thereon as the screw is rotated. The back end of the contact nose is provided with an annular surface 22a disposed radially to the longitudinal axis of the screw and adapted to engage an annular shoulder 35 of the shank 23 in flat co-planar relationship therewith. As the screw is rotated and driven inwardly to contact the wellhead component 14 to be actuated, the flat contact surface 32 of the nose of the screw will engage in sliding contact with the cooperating camming surface 17a. Since the contact nose does not rotate against the cooperating camming surface 17 a of the wellhead component and engages over a large contact area, contact stresses are reduced and susceptibility to galling is minimized. The shank 23 includes an externally threaded section 23a adjacent its outer end which receives a packing nut 25. The packing nut 25 is externally threaded whereby it may be threaded into the bore 11 provided in a wellhead structure 12 and used to energize a packing assembly sleeved about the shank 23 by compressing the assembly against a shoulder provided in the bore 11.

Holddown screw

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 energized mechanically preloaded packing assembly (48, 68) of a high pressure gate valve (10). The packing assemblies are positioned in an annular space about the valve stems (36, 64) for sealing between the valve stems and bonnet (38) or valve body (12). The packing assemblies include an energizer ring (78) which is positioned within the annular space having an outwardly facing precision cut frusto-conical end surface (82) relative to the flow passage (16, 18) of the valve. A plurality of Belleville springs or spring washers (98) with a generally frusto-conical shape are positioned adjacent and in concave relation to the outer end (82) of the energizer ring. The cone angle of the spring washers are smaller than the cone angle of the energizer ring. The packing assembly further includes at least one packing ring set positioned outside the spring washers (106, 108) which includes a stack of plastic packing elements (110) which are sandwiched between a pair of retainer rings (112, 114). A packing gland nut (118) is disposed in contiguous relation to the packing ring set and is externally threaded for accommodating its connection with the valve body whereby the gland nut is axially adjustable to apply axial pressure on the packing ring set and spring washers. The spring washers (98) are compressed until their cone angle matches the cone angle of the energizer ring (78) such that the spring washers exert a predetermined preload onto the packing ring set to provide a low pressure seal between the stem and valve body.

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Katy, TX, United States of America

Brett A Babbitt