Abstract: A new and improved gate valve suitable for use with high pressure, high temperature fluids such as those developed in coal gasification processes and the like which comprises a valve gate assembly including opposed outwardly facing valve discs is bodily movable from a valve open position to a valve seat confronting position in which the valve discs are aligned with but spaced from opposed valve seats in the flow passage. Upon further downward movement of the valve stem the valve discs are moved laterally outwardly into engagement with the valve seats. In order to accommodate situations where the opposed valve seats are spaced relatively close together, the valve discs are mounted on annular spring washers which normally bias said valve discs away from said valve seats. A pair of toggle elements are actuated by downward movement of the valve stem to force the valve discs laterally outwardly into engagement with the valve seats after the assembly has been moved to the valve seat confronting position.

Abstract: A high energy loss fluid flow control device suitable for use with high temperature, abrasive coal liquids, gases and the like comprises an elongated body having an axially extending bore with longitudinally spaced apart inlet and outlet passages in communication with the bore. An elongated valve member is mounted for sliding axial movement within the bore between open and closed positions. The valve member includes an outer surface spiralling about a longitudinal axis from a maximum diameter portion adjacent one passage toward a minimum diameter portion adjacent the other passage. The bore of the elongated body includes a surface in close facing relation with the spiralling surface of the valve member and this surface also is spiralled about a longitudinal axis from a minimum diameter portion towards a maximum diameter portion.