Abstract: A turboexpander, particularly suited for use in a cryogenic rectification system, comprises a center housing rotatably supporting an elongated shaft to opposite ends of which are mounted a turbine wheel within a turbine housing and a compressor wheel within a compressor housing or a brake within a load housing. The turbine wheel has circumferentially spaced turbine blades. Process fluid is introduced so as to flow through annular nozzles or guide vanes which encompass the turbine wheel. The guide vanes direct the process fluid through the turbine blades and each extends between a leading edge more distant from the turbine wheel and a trailing edge less distant from the turbine wheel. Each guide vane is substantially uncontoured between its leading edge and the trailing edge and is substantially thicker at the leading edge than at the trailing edge.

Abstract: An improved helical dry screw expander particularly suited for cryogenic service and its use in a cryogenic rectification system. The improved helical dry screw expander is particularly advantageous in a cryogenic waste expansion cycle particularly for nitrogen production.

Abstract: An improved helical dry screw expander particularly suited for cryogenic service and its use in a cryogenic rectification system. The improved helical dry screw expander is particularly advantageous in a cryogenic waste expansion cycle particularly for nitrogen production.

Abstract: A cryogenic rectification system employing a coupled expander and compressor wherein a process stream employs system energy to drive the expander to compress product nitrogen while generating refrigeration to assist in carrying out the rectification thereby carrying out the rectification at a lower pressure.

Abstract: A bearing support system providing axial thrust load control of bearing supporting a rotating element, by retaining the bearings with a slotted inner ring and supporting the inner ring with a radially spaced outer ring by means of a plurality of circumferentially spaced supports which are radially stiff but axially flexible.

Abstract: An investment casting process employs a low-cost plastic pattern manufactured by machining. A mold is cast around the plastic pattern following which the pattern is removed from the mold to leave a mold cavity which molten metal or the like may be poured to produce a finished part. Reusable plastic patterns may be formed by casing silastic rubber. The silastic rubber patterns may be mechanically separated from the mold without damaging the pattern.

Abstract: A clearance-type seal for use in rotary fluid handling machinery for preventing lubricant from leaking into working fluid by flowing by capillary action along a fixed surface wherein a coating which is not wetted by the lubricant is placed on the fixed surface of the machinery such that any lubricant which may flow onto the coating is caused to bead up and is thus easily swept away by flow of seal gas.