National Oilwell Varco, L.p.

National Oilwell, Inc.

Mark A Staggs

Andrew Dale Riley

James C Aday

Apparatus and methods for constructing a valve assembly comprising an anti-friction ring. The anti-friction ring allows a closure member in the valve assembly to more freely rotate during operation of the valve assembly. Consequently, the closure member strikes a sealing member in different rotational positions during repetitive cycling of the valve assembly.

Rotating bonded valve assembly

Apparatus and methods for constructing a valve comprising a sealing member and a hollow ball operable to sealingly engage the sealing member. A guide housing disposed about said hollow ball and does not constrain rotation of said hollow ball. A spring is disposed between the hollow ball and the guide housing so as to bias the hollow ball into sealing engagement with the sealing member. The hollow ball is constructed from two unequal sized portions and may comprise a hollow, spherical body having an aperture and a plug sized so as to closely fit within the aperture.

Hollow ball valve assembly

A hydraulic system is provided for securing a cylinder liner to a pump module of a reciprocating pump, such as a mud pump. The hydraulic system includes a body attached to the pump module, a ram in sliding contact with the body and having a mating surface, preferably a radial shoulder, contacting the liner. Upon pressurization of fluid in a chamber defined by the body, the ram, and a pair of seals therebetween, the ram slides between a first position and a second position. The ram secures the liner to the module when in the first position and is removable in the second position. The system further includes a locking ring that engages the body, may be hand rotated upon pressurization, and mechanically holds the ram in the first position in the absence of hydraulic pressure. The hydraulic system is adapted to apply a precise axial securing force and to aid alignment of the liner.

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McAlester, OK, United States of America

Mark A Staggs