Abstract: A vacuum pump (10) includes a pump casing (56) having an inlet port (54a), an outlet port (54b), and pump chambers (50a-50f) defined therein, rotational shafts 60 having opposite ends rotatably supported by bearings (84a, 84b) on the pump casing (56) and extending longitudinally in the pump casing (56), and rotors (62a-62f) housed in the pump chambers (50a-50f) and coupled to the rotational shafts (60) for rotation in unison with the rotational shafts (60). The pump casing (56) has an atmosphere-vented compartment (52) defined therein which is held in fluid communication with the outlet port (54b) of the pump casing (56) and vented to the atmosphere.

Abstract: A helical screw compressor includes two rotors which are mounted in the rotor housing. The helical screw compressor includes sealing arrangements (11, 11?) for sealing the pressure-sided shaft journals of the rotors. Each sealing arrangement includes a plurality of annular seals (11a, 11b) which are arranged in a row adjacent to each other, and an annular-shaped discharge chamber (51) is associated with the system on an intermediate position and is connected, via a discharge channel (53), to the chamber in the rotor housing, wherein pressure which is higher than the atmospheric pressure. Preferably, the discharge channel is connected to the suction chamber (10) of the rotor housing (1), and is impinged upon by precompressed gas from an upstream compressor step.

Abstract: A screw compressor rotor housing is surrounded by a cooling housing that forms an annular cooling chamber. The cooling chamber is interrupted at one point by a separating wall that connects the rotor housing to the cooling housing. Coolant is fed at an inlet opening and is directed at the bottom side of the separating wall by an entrance channel, is redirected, and flows around the rotor housing until it reaches the top side of the separating wall. The coolant is redirected and is withdrawn through an exit channel that runs upward to the outlet opening. A bleed opening in the wall of the entrance channel and a vent opening in the wall of the exit channel allow for a residual amount of air to remain in the cooling chamber when it is filled with coolant, and for a residual fluid to remain when it is emptied.

Abstract: A screw compressor has a gear housing (1) from one side of which the rotor housing (3) containing the two screw rotors freely projecting outward. An oil supply container (7) is also located freely projecting out from the gear housing (1) approximately parallel to the rotor housing (3) and thermally separated from the rotor housing by means of an air gap. A ventilation channel (109) in the rotor housing (3) to vent the rotor shaft seals opens up to one point in the rotor housing that is protected against direct access by the oil supply container (7) mounted in front of it as well as by additional shoulders (111).

Abstract: A compound vacuum pump includes a pump body divided by a partition into upper and lower chambers. A screw pump section occupies the lower chamber and a Roots-type pump section occupies the upper chamber. The Roots-type pump section comprises two rotors each with a disc for rotation in a bore of the partition.

Abstract: A seal arrangement for an engine-driven supercharger to prevent burning and abnormal wear of an rubber-made oil seal fitted on a shaft of a rotor of the supercharger. The supercharger includes a housing, a rotor chamber is formed in the housing and the rotor is rotatably placed in the rotor chamber. A shaft chamber is formed next to the rotor chamber. The rotor shaft projects from the rotor chamber into the shaft chamber in a longitudinal direction of the rotor. A bearing is provided inside the shaft chamber for supporting the rotor shaft at a free end of the rotor shaft. A lubrication oil is fed to the bearing. The supercharger sucks external air into the rotor chamber by making the rotor chamber pressure negative and rotates the rotor for compressing the air in the rotor chamber. The oil seal is fitted on the rotor shaft between the bearing and the rotor chamber for defining an oil chamber in the shaft chamber between the oil seal and the bearing.

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 closed type motor-driven compressor includes a motor accommodated in a closed container and a compression mechanism connected through a crank shaft to the motor. A shielding member having a cylindrical portion substantially concentric with the axis of the compression mechanism is disposed between the motor and the compression mechanism. This shielding member defines a shielding air space between the motor and the compression mechanism for preventing a permeation of a lubricating oil. An inlet of a discharge pipe of the closed type motor-driven compressor is positioned inwardly of this shielding air space.

Abstract: A thermal isolation arrangement for use in a co-rotating scroll refrigerant compressor includes various thermal insulation elements adapted to minimize heat transfer between hot rotating members of the scroll fluid device and the return refrigerant to be compressed, and between hot lubricant in the compressor and the return refrigerant. The thermal isolation elements of the present invention may be used individually or collectively to minimize the preheating of the inlet refrigerant so as to maintain the density of the return refrigerant being compressed to thereby increase the total efficiency of the scroll fluid device.

Abstract: An oil-free screw compressor prevents a filter for separating oil mist from a gear case exhaust gas from clogging due to increase pressure loss in the filter, thereby suppressing increasing of an gear case inner pressure and further ensuring a removing of the oil mist from the exhaust gas. The oil-free screw compressor comprises a gear case exhaust pipe connected to a filter container containing a filter element for separating the oil mist, and a vacuum ejector having a suction port connected to second side space of the filter element contained in the container so as to make the pressure of the second side space of the filter element in the container negative pressure.

Abstract: A vacuum pump system comprising a first vacuum pump having at least one pumping chamber with port means for communication with an enclosure to be evacuated and having mechanical pumping means mounted on at least one shaft whose bearings and/or gears are contained in a housing and a second vacuum pump having a first pumping chamber with means for communication with the chamber of the first pump and at least one further pumping chamber wherein means are provided for communication between the housing of the first pump and a further pumping chamber of the second pump.

Abstract: Bearing apparatus for movable vane compressor is provided with a pressure-reducing passage extending from an annular clearance between the inner side surface of the bearing and the side surface of the rotor to the open air or the like, such as the suction-chamber and the suction-working space. Compressed air enters the annular clearance through a gap between the inner side surface of the side housing and the side surface of the rotor from the compression-working space between two adjacent vanes and then runs out through the pressure-reducing passage without pushing the bearing grease from the bearing.

Abstract: A vacuum pump includes an evacuation chamber, a gear chamber, a partition separating the evacuation chamber from the gear chamber, a rotary pump shaft extending through the partition and having one end connected to a vane arranged for rotation in the evacuation chamber and having another, opposite end extending into the gear chamber, a shaft bearing surrounding the pump shaft and received in the partition, a labyrinth seal surrounding the pump shaft and received in the partition for sealing the evacuation chamber from the gear chamber, an oil sump defined in the gear chamber for accommodating oil therein, an evacuation device for generating a vacuum in the gear chamber and an oil loss preventing arrangement for avoiding an oil deficiency in the gear chamber due to the vacuum generated therein.

Abstract: A seal system in a rotary engine includes apex seals held against an inner peripheral wall surface of a rotor housing, seal rings disposed between the apex seals and a side wall surface of the rotor housing, seal rings disposed between sliding plates mounted on a rotor and the side housing member, a split seal ring disposed between the side housing member and the rotor, and an air seal unit for supplying a flow of compressed air across a clearance between the rotor and the rotor housing to prevent gas leakage between compression and combustion stroke chambers.

Abstract: A rotary piston pump includes a casing and partitions within the casing defining an expansion chamber and with a gear and bearing chamber on one side of the expansion chamber and a bearing chamber on the other side. The partitions between the expansion chamber and the bearing and gear and bearing chambers are provided with passages for receiving shafts serving for the transmission of the rotary movement from gears to the pistons of the pumps. The passages between the chambers are provided with split seals which are composed of two parts separated by a pressure equalization chamber.

Abstract: A flow divider is described for accurately dividing and metering the flow of a common fluid, such as fuel oil, to a plurality of fluid outlets. The flow divider includes a plurality of metering gear sets rigidly fixed on two parallel common continuous shafts, with each of the gear sets separated from adjacent gear sets by separater spacers also fixed on the shafts but free to move in a common radial cavity formed by a split housing enclosing the shafts and gears. The two parallel common continuous shafts are supported at each end by roller bearings which are separated from the gear sets by means of a seal and are lubricated by a separate source of lubricant. The roller bearings on one end of the parallel shafts are fixed in an axial location relative to the shafts and the roller bearings on the other end of the common shafts are free to move axially without experiencing binding or seizing of the shafts or roller bearings.

Abstract: In screw compressors for fluids there is normally leakage of fluid axially through the rotor-shaft bearing assemblies at the high-pressure end of the casing housing the interacting rotors. To obviate or mitigate the resulting inefficiency in the operation of the compressor, and also reduce atmosphere pollution arising from the leakage, a fluid coupling is provided between said bearing assemblies and an additional fluid inlet opening in the compressor casing, said additional opening being positioned to communicate with a land of the rotor when the rotor is at or beyond rotor cut-off, so that fluid leaking from the compression chamber is recirculated to the compression chamber.