Abstract: An improved plastic valve body design and construction which has strength and durability similar to that of steel valve bodies but with significantly reduced manufacturing time and cost. The valve body comprises a unique and nonobvious combination of a previously unused plastic material and a complex rib design that results in performance similar to that of steel valves. The valve body is preferably comprised of a nylon/Kevlar composite material. A plurality of ribbed members connect outer and inner faces of the valve body to provide increased strength and durability. The plastic valve body has the ability to deform to mate with the valve seat and thus extrusion gaps are eliminated. This allows use of more desirable softer polyurethane inserts.

Abstract: An improved optical system for treatment of disorders of the skin, especially vascular lesions, such as PortWine Stains. The system irradiates the skin with radiation at a predetermined wavelength and cools the skin during a predetermined time interval in coordination with delivery of the radiation. The absorption of the radiation by the skin and the change in temperature of the skin is monitored by the system and the operation of the radiation delivery system is controlled to optimize treatment of the vascular lesion. The source of irradiation is an arc lamp and the cooling system delivers a cooling gas to a lens in contact with the skin. The cooling gas can be carbon dioxide, freon, or any other appropriate gas. The lens used has a high heat conductivity and may be formed of sapphire.

Abstract: An improved method and apparatus for controlling the direction of advance of a rotary drill to produce a borehole profile substantially as preplanned with minimal curvature while maintaining optimum drilling performance. The preferred embodiment of the system comprises a drill string, a rotatable drill bit carried on said drill string, and a compliant subassembly in said drill string, said compliant subassembly facilitating changes in the direction of drilling of said borehole. The system further comprises a plurality of sensors for measuring strains within the compliant subassembly and for producing data signals corresponding to the strain measurements. A control system is operable to use the data signals to change the direction of the borehole by applying a shear force to the drill bit.

Abstract: An improved valve seat which significantly decreases the impact stress caused by the impact of a mud pump valve body against the valve seat. The valve seat comprises a generally cylindrical body portion with a sealing surface which is sloped from the outer surface of the cylindrical body portion toward an interior throat of said cylindrical body portion. The valve body comprises a generally disc-shaped portion and a truncated conical portion. An elastomer insert is received in a groove in the valve body. The conical portion of the valve comprises a sloped face, including a metal portion and an elastomeric portion formed by the elastomeric insert. In the valve seat of the present invention, an annular pressure relief groove in the cylindrical body portion of the valve seat allows the sloped face of the valve seat to flex thereby relieving a significant amount of the impact load between the opposing face of the valve assembly.