Abstract: A screw compressor includes an outlet housing. The outlet housing includes a passage that is configured to communicate compressed fluid from a screw rotor to a discharge. A removable cover plate is configured to cover a portion of the passage. A method of varying a volume index for a screw compressor is also disclosed.

Abstract: This screw compressor is provided with a screw rotor, a casing accommodating the screw rotor, and a liquid feed mechanism for feeding a liquid into an operating chamber enclosed by the casing, wherein the pitch of the screw rotor changes in the axial direction from a suction end surface toward a discharge end surface.

Abstract: A screw spindle pump having a spindle housing, in which a drive spindle and at least one running spindle which meshes therewith are received in spindle bores, and having an outer housing which encloses the spindle housing and on which an axial inlet port and a radial outlet port are provided, wherein the spindle housing has an axial fluid outlet for the fluid delivered through the spindle housing by the drive spindle and the running spindle, which axial fluid outlet communicates with a fluid chamber, which is formed between the spindle housing and the outer housing, extends around 360°, and in turn communicates with the radial outlet port.

Abstract: A rotor for a mud motor includes a core having a first outer shape, and a shell positioned around the core, the shell having a second outer shape that is different from the first outer shape, the second outer shape defining one or more lobes and one or more cavities that are configured to engage a bore of a stator during rotation of the rotor relative to the stator. A thickness of the shell varies as proceeding around the core, from a non-zero minimum thickness to a maximum thickness.

Abstract: A method for conveying a fluid through a screw pump, wherein at least one drive spindle of the screw pump is driven by an asynchronous motor, wherein, the asynchronous motor is operated at a first nominal frequency, a gas/liquid mixture being conveyed as fluid, a measurable variable depending on a liquid content of the fluid is registered, and after a fulfillment of a frequency-change condition depending on the measurable variable the asynchronous motor is operated at a second nominal frequency, reduced in comparison with the first nominal frequency.

Abstract: The present invention relates to rotary screw positive displacement machines used as a vacuum pump wherein additional intake air is provided allowing cooling to the invention which permits extended operation at extreme vacuum pressure. The rotary screw nature of the vacuum pump allows operation without additional lubrication with the additional intake air ensuring that thermal expansion will not disrupt the tight tolerances of the invention. The invention allows simultaneous operation as a vacuum pump and air compressor.

Abstract: Provided is a fluid machine configured such that liquid supplied to a working chamber from the outside of the fluid machine is dispersed extensively in the working chamber. This fluid machine is constituted of a screw rotor and a casing for accommodating the screw rotor and is provided with a liquid supply section for supplying liquid into a working chamber from the outside. The liquid supply section is configured so that liquid is dispersed in the longitudinal direction of the tooth groove of the screw rotor rather than in the width direction thereof.

Abstract: A single-screw compressor includes a screw rotor with helical grooves, a gate rotor assembly including first and second gate rotors, and a casing housing the screw rotor and the gate rotor assembly. A rotor support member is attached to the first and second gate rotor rotors, and is rotatably supported by the casing. Each of the helical grooves of the screw rotor has a front sidewall surface and a rear sidewall surface. Each of the gates of the first gate rotor slides only on the front sidewall surface of the helical groove in which the gate has entered. Each of the gates of the second gate rotor slides only on the rear sidewall surface of the helical groove in which the gate has entered. The first and second gate rotors of the gate rotor assembly are coaxially arranged and relatively displaceable in a circumferential direction.

Abstract: A variable capacity screw compressor comprises a suction port, at least two screw rotors and a discharge port being configured in relation to a selected rotational speed that operates at least one screw rotor at an optimum peripheral velocity that is independent of a peripheral velocity of the at least one screw rotor at a synchronous motor rotational speed for a rated screw compressor capacity. A motor is configured to drive the at least one screw rotor at a rotational speed at a full-load capacity that is substantially greater than the synchronous motor rotational speed at the rated screw compressor capacity. A variable speed drive receives a command signal from a controller and generates a control signal that drives the motor at the selected rotational speed.

Abstract: A compressor is provided including a housing having a suction inlet and a discharge outlet. A compression mechanism within the housing is configured to receive a vapor at the suction inlet and to provide a compressor vapor to the discharge outlet. A volume index valve is arranged near the discharge outlet. The volume index valve includes a piston positioned within a hollow chamber and configured to move between a closed position and an open position to provide a bypass flow path from an intermediate portion of the compression mechanism to the discharge outlet. The piston is configured to move within the chamber automatically in response to the operating pressure of the vapor within the compressor.

Abstract: A volumetric flow meter, including a casing (10) fitted into a duct (C; 51, 62, 63) and including a base body (11) and a cap (13) cooperating to define a housing chamber (15), the housing chamber (15) being on opposite sides delimited by a base plane (11c) formed in the base body (11) and by a cap plane (13d) formed in the cap (13). Through the cap (13) there is formed an inlet passage (13e) communicating with the housing chamber (15) and extending orthogonally to the base plane (11c). Through a bottom (11d) of the base body (11) there is an outlet passage (11e) communicating with the housing chamber (15) and extending orthogonally to the base plane (11c). The flow meter has rotors (17, 18) mounted rotatably within the housing chamber (15), a permanent magnet (19) arranged on board one of the rotors (17), and a magnetic sensor (20).

Abstract: A compressor system includes a compressor having a rotor; a bearing supporting the rotor, wherein the bearing is disposed in a bearing cavity; and wherein the bearing has a near frictionless coating; and a purge gas system in fluid communication with the bearing cavity and constructed to purge air from the bearing cavity and supply the bearing cavity with the purge gas during operation of the compressor. The purge gas can be nitrogen and the near frictionless coating can be a near-frictionless diamond-like carbon coating.

Abstract: A compressor (20) comprises: a housing assembly (22) having a plurality of ports including a suction port (24) and a discharge port (26); a male rotor (30) mounted for rotation about an axis (500); a female rotor (32) enmeshed with the male rotor and mounted in the housing for rotation about an axis (502) for drawing a flow from the suction port, compressing the flow, and discharging the compressed flow through the discharge port. The housing assembly comprises: a motor case (54); and a cover (60) bearing the suction port. The cover comprises a unitary piece forming: a mounting portion (63) mounted to an adjacent end (55) of the motor case, said adjacent end being large enough to pass the motor; and a fitting portion (62) extending to a rim (66) at the suction port and bearing an external groove (200).

Abstract: A compressor element of a screw compressor inlet side and an outlet side and two helical rotors, respectively a male rotor with a drive for the male rotor and a female rotor that is driven by the male rotor by means of synchronisation gearwheels with at least one synchronisation gearwheel on the male rotor, wherein the drive and synchronisation gearwheels of the male rotor are chosen such that, upon being driven with acceleration of the rotors without gas forces, the resulting mechanical drive force that is exerted by this drive and by this synchronisation gearwheel on the male rotor has an axial component that is directed from the outlet side to the inlet side and that the movement of the male rotor in the axial direction from the outlet side to the inlet side is fixed by means of a single axial single-acting or double-acting bearing.

Abstract: A screw compressor element with a housing and two screw rotors that are affixed in the housing in a double cylindrical chamber provided to this end, whereby the housing is provided with an inlet opening on the inlet side of the screw compressor element, whereby the inlet opening extends in the cylindrical walls of the double cylindrical chamber with at least a section that extends in an axial direction, and a transverse section connecting thereto in the form of a strip that extends from the axial section on the inlet side to a side of the section in a direction transverse to the axial direction.

Abstract: An oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of the screw rotors; a shaft seal device including an oil seal portion and an air seal portion; an atmosphere open hole formed in the shaft seal device; at least one communication hole formed in the rotary shaft; and an annular space communicating the atmosphere open hole with the at least one communication hole communicate with each other. The annular space includes an inner peripheral annular space formed on an inner peripheral side of the casing. Assuming an open cross-sectional area of the inner peripheral annular space as S1, a total open cross-sectional area of the communication holes as S2, an open cross-sectional area of the i-th communication hole out of the communication holes as S2i, and the number of communication holes as n (n being a natural number of 1 or more), a following relationship is satisfied.

Abstract: A compressor exhaust structure includes a machine body, an exhaust bearing seat provided at an exhaust end of the machine body and an oil separating barrel covering the exhaust bearing seat, the exhaust bearing seat is provided with a first exhaust chamber, the machine body is provided with a second exhaust chamber, a third exhaust chamber is formed between the exhaust bearing seat and an inner wall of the oil separating barrel, the first exhaust chamber is in fluid communication with the second exhaust chamber, the second exhaust chamber is in fluid communication with the third exhaust chamber, and the third exhaust chamber is in fluid communication with a discharge port of the oil separating barrel. The compressor exhaust structure increases the flow path of the gas flow, facilitates the insulation of gas flow noise and reduces gas flow pulsation.

Abstract: An exhaust bearing seat, a screw compressor and an air-conditioning unit are provided. The exhaust bearing seat is provided with a discharge port, wherein an opening of the discharge port is orientated in such a way that, if the exhaust bearing seat is sheathed in a housing, gas exhausted from the discharge port has a component which rotates along an inner wall of the housing and around an axial direction of the housing. The discharge port is able to guide the gas flow to rotationally flow along the inner wall of the housing body and around the axial direction of the housing, which extends the flow path of the gas flow inside the housing, and facilitates the reduction of noise of the gas flow pulsation.

Abstract: A gear pump or a gear motor includes a casing, a helical drive gear, a helical driven gear, a drive-side space, and an idler-side space. The drive and driven gears mesh with each other in the casing to partition inside of the casing so as to include high and low pressure spaces. The drive-side and idler-side spaces are each configured to allow pressure therein to become higher than a pressure in the low-pressure space. The drive-side space faces an end portion of a drive shaft rotatably supporting the drive gear. The idler-side space faces an end portion of an idler shaft rotatably supporting the driven gear. The end portion of the drive shaft is pushed in a predetermined direction by working fluid supplied to the drive-side space. The end portion of the idler shaft is pushed in the predetermined direction by working fluid supplied to the idler-side space.

Abstract: The invention relates to a screw spindle pump, with a housing (2) which surrounds a delivery chamber (5), two spindles (7, 8), namely a drive spindle (7) and an opposed running spindle (8), a housing insert (6) which is arranged in the housing (2) and in which the spindles (7, 8) are accommodated, at least one bearing element (13?, 13?), which is connected to the housing insert (6) and on which bearings (12) of the spindles (7, 8) are arranged, and with at least one housing cover (14?, 14?), closing a housing opening. It is the object of the invention to provide a screw spindle pump at which maintenance and inspection work can be carried out more simply and cost-effectively. The invention achieves this object in that the bearing element (13?, 13?) together with the housing insert (6) and the spindles (7, 8) accommodated therein forms a unit (15) which, after the housing cover (14?, 14?) is taken off, is removable from the housing (2) through the housing opening.

Abstract: A baffle for a gear may comprise a baffle wall and a baffle outlet, the baffle wall having a peripheral portion at least partially defining a channel, the channel extending circumferentially around an axial centerline, the channel configured to receive lubricant through a slot, the slot extending circumferentially around the axial centerline. The baffle wall may be configured to prevent a subset of gear teeth from receiving lubricant. A width of the slot may vary along a circumferential direction. A cross-section area of the channel may vary along the circumferential direction. The cross-section area of the channel may increase along a direction of rotation of the subset of gear teeth.

Abstract: A screw machine, in particular screw compressor, includes a machine housing, screw rotors forming a rotor pair which is mounted in the machine housing, an oil supply system via which bearings and seals of the screw rotors can be supplied with oil for lubricating and/or cooling, wherein the oil supply system has an oil supply and oil feeds, wherein the oil supply system includes a pressure sensor, which detects a pressure in the oil discharge or oil return or a pressure difference between the pressure in the oil discharge or oil return and a pressure in the oil feeds, the oil supply system furthermore includes a control device, which open-loop or closed-loop controls the pressure in the oil feed or the pressure difference dependent on the measurement signal of the pressure sensor.

Abstract: A compressor having a compressor wall that has an interior surface that defines a compression chamber, in which a rotor or pair of rotors operates to compress a fluid. To do so, the rotors are in operative communication with the interior surface. The compressor also includes an injection port in the compressor wall and opening into the compression chamber, the injection port being in fluidic communication with a second fluid. The compressor can also include an insert in operative communication with the injection port, wherein the insert and the injection port define therebetween a gap through which the second fluid enters the compression chamber.

Abstract: A screw compressor includes a casing, a screw rotor, a low-pressure-side bearing, and a low-pressure-side bearing holder holding the low-pressure-side bearing. The screw rotor is housed in the casing to form a compression mechanism to compress a refrigerant. The low-pressure-side bearing is arranged in a low-pressure-side region inside the casing and rotatably supports a drive shaft of the screw rotor. The casing has a suction port with an opening facing the low-pressure-side bearing holder as viewed along an axial direction. A filter member is attached to the suction port to filter out contaminants contained in the refrigerant being sucked into the casing. The filter member has a cylindrical shape with a bottom. A peripheral portion of the filter member adjacent to an opening of the filter member is fixed to the suction port. The bottom of the filter member is fixed to the low-pressure-side bearing holder.

Abstract: A screw spindle pump having a housing hi which a drive spindle and at least one running spindle having profile assemblies which engage inside each other are received, the free end of the drive spindle and the end portion of the running spindle being supported on a plate which is arranged in the housing, the plate having two faces which are inclined in opposing directions relative to each other and which form a V-shape and on which one of the spindles is supported, respectively.

Abstract: A screw compressor is disclosed, which includes a male rotor and a female rotor and an oil separator. The oil separator includes an outer cylinder, an inner cylinder located inside the outer cylinder, and an introducing flow path. An upper end portion of the inner cylinder is held by the oil separator and an outer wall of the inner cylinder is held independently of the inner wall of the outer cylinder. A diameter of an inner wall of the outer cylinder is configured so that the diameter is gradually reduced along a swirl flow path. Moreover, refrigerant that flowed in swirls and goes down along the swirl flow path. The separated gas refrigerant flows from a lower end portion of the inner cylinder into the inner cylinder and goes up and the separated oil flowing down along the inner wall surface of the outer cylinder.

Abstract: A compressor (10) comprises counter rotating and intermeshing twisted rotors (18) and (20) disposed in a housing having an air intake plate (28) and an outlet (16). The outlet (16) has a first edge (60) and a second edge (70) which nm parallel with a length of the rotors (18) and (20) respectively. A gap (62) is formed in the outlet near a junction of the edges (60) and (70). Air which is compressed by the rotors (18) and (20) is able to bleed through the gap (62) in advance of trailing edges of lobes of at least one of the rotors (18) passing its corresponding edge (60). Also the rotors (18), (20) are arranged so that the trailing edge of a lobe of rotor (18) passes edge (60) before a trailing edge of a lobe of rotor (20) passes edge (70).

Abstract: In a gear pump in which a driving rotor that is driven by a driving source meshes with a driven rotor that is driven by the driving rotor for rotation to pump a hydraulic oil, only one of the driving rotor and the driven rotor is given the steam treatment while the other remains untreated.

Abstract: The disclosure concerns a Roots-type blower comprising a housing defining first and second transversely overlapping cylindrical chambers and at least one inlet port and an outlet port; first and second meshed, lobed rotors, each lobe having a top land sealingly cooperating with the cylindrical chambers; a plurality of control volumes for transfer of fluid, each control volume being defined by a pair of adjacent lobes on one of the rotors, and at least one of the cylindrical chambers; and blowholes formed within the cylindrical chambers in connection with meshing of the lobes of the first and second rotors. The blower further comprises at least one backflow slot extending through the housing wall of each cylindrical chamber for effecting a leakage of fluid from downstream the at least one outlet port into a control volume.

Abstract: A compressor for compressing refrigerant in a refrigerant circuit includes a housing defining a compression chamber. A screw rotor is mounted within the housing and configured to form a pocket of high pressure refrigerant and a pocket of low pressure refrigerant within the compression chamber. The screw rotor has a rotor shaft rotating about an axis. A bearing cavity includes at least one bearing rotatably supporting the rotor shaft. A partition through which the rotor shaft extends separates the bearing cavity from the compression chamber. A contacting seal is sealingly engaged with the rotor shaft and disposed in the bearing cavity proximate the partition. A passage has an opening adjacent the rotor shaft between the contacting seal and the compression chamber and in fluid communication with the pocket of low pressure refrigerant.

Abstract: There is provided a stator seal structure in a uniaxial eccentric screw pump by which the abrasion resistance of sealing mechanisms is improved and the pumped fluid can be prevented from stagnating in the sealing mechanisms. The stator seal structure is provided with a pair of sealing mechanisms for sealing between a housing and an intake side end portion, and between the housing and a discharge side end portion of the stator. The pair of sealing mechanisms is provided with ring-shaped secured rings respectively secured to the housing. The secured rings are respectively attached with elastic bodies for ensuring contact pressures between the sliding seal surface of the stator and the sliding seal surface of the secured rings with the elastic forces of the elastic bodies and for sealing between the secured rings and the housing.

Abstract: A screw compressor includes a rotatable screw rotor and a plurality of gate rotors. The screw rotor has helical grooves formed in an outer circumferential surface of the screw rotor. The gate rotors have a plurality of radially disposed teeth meshing with the grooves of the screw rotor. The helical grooves include a first screw groove and a second screw groove. The first screw groove compresses a fluid from one end side of the screw rotor to an other end side of the screw rotor. The second screw groove compresses the fluid from the other end side of the screw rotor to the one end side of the screw rotor.

Abstract: A reduced noise screw expander is described, which comprises a main rotor and a gate rotor each having an ‘N’ profile. The rotors are designed so that the torque on the gate rotor caused by pressure forces is in the same direction as the torque on the gate rotor caused by frictional drag forces. A method of designing a screw machine exhibiting reduced noise is also described. The screw machine has two or more rotors having an ‘N’ profile, and the method involves determining a ratio r/r1, where r is the main rotor addendum and r1 is the radius of the rack round side, and ensuring that this ratio is greater than 1.1 where the screw machine is to be a screw compressor or less than or equal to 1.1 where the screw machine is to be a screw expander.

Abstract: Multistage pump comprising a plurality of components which include a plurality of pre-assembled pump modules, having at least one twin screw pump module. The multistage pump further has an elongate sleeve for housing the components, and a securing device attachable or engagable with a portion of the elongate sleeve. The securing device is operable to fixedly retain the components within the sleeve. Each of the pre-assembled pump modules has at least one thrust bearing.

Abstract: A toothed wheel machine including a housing for receiving two meshing and especially helical-toothed wheels. The toothed wheels are axially mounted in a sliding manner by axial surfaces between bearing bodies received in the housing, and radially by a bearing shaft received in the bearing bodies. During the operation of the toothed wheel machine, an axial component of a force resulting from the hydraulic and mechanical forces generated during operation acts on each toothed wheel in the same axial direction. A counter-force against the respective axial force component is applied to the toothed wheels and/or bearing shafts, each counter-force applying the same amount of pressure as the respective axial force component, or less than same.

Abstract: A multi-rotor screw compressor includes a housing, a sun rotor, and first and second planet rotors. The first planet rotor intermeshes with the sun rotor to define a first compression pair. The second planet rotor intermeshes with the sun rotor to define a second compression pair. The first and second compression pairs are rotatably mounted in the housing. The housing includes a first port, a portion of which is in communication with the first compression pair, and a second port, a portion of which is in communication with the second compression pair. The portions of the first and second ports which communicate with the first and second compression pairs have a different geometry for offsetting pulsations in a working fluid flowing through the ports.

Abstract: An improved bearing housing of a rotary screw compressor is described. The bearing housing is generally shorter than a convention bearing housing. The bearing housing can be configured to enclose and support radial bearings of the screw compressor. The bearing housing can be configured not to enclose axial bearings of the screw compressor in an axial direction.

Abstract: A variable capacity screw compressor comprises a suction port, at least two screw rotors and a discharge port being configured in relation to a selected rotational speed that operates at least one screw rotor at an optimum peripheral velocity that is independent of a peripheral velocity of the at least one screw rotor at a synchronous motor rotational speed for a rated screw compressor capacity. A motor is configured to drive the at least one screw rotor at a rotational speed at a full-load capacity that is substantially greater than the synchronous motor rotational speed at the rated screw compressor capacity. A variable speed drive receives a command signal from a controller and generates a control signal that drives the motor at the selected rotational speed.

Abstract: An assembly of a compressor for pressurizing a fluid includes a main housing having a portion being substantially planar. The housing defines at least two parallel intersecting bores. At least two rotors are journaled for rotation within the bores. A plurality of vent channels in the main housing extend outwardly from at least one bore through the portion being substantially planar. The vent channels are configured for the fluid to flow through the vent channels. A slide valve assembly is operably connected to the housing proximate the plurality of vent channels. The slide valve assembly has a valve plate wherein the valve plate has a substantially planar side that is sealingly engaged with the planar portion of the main housing. The valve plate is positioned into one of a plurality positions relative to the vent channels.

Abstract: A gear pump for pumping a fluid while adjustably controlling a gap between gears and end plates of the gear pump housing. The gear gap is controlled by a gear gap adjustment mechanism operably associated with a gear shaft to move the gear and shaft along a longitudinal axis of the shaft. The gear pump can also include a removable and replaceable friction shield to adjust the gap between the gear and the end plate. The gear pump can further include a dynamic shaft seal assembly for adjusting the sealing about the shaft.

Abstract: A refrigerant compressor (10) for use in a chiller-heater system that can provide chilled water at less than 10° C. and hot water at more than 80° C. without the need for additional heat input, the compressor (10) being configured to provide a compression ratio of at least 18:1 and a temperature lift across the compressor of at least 80K, and the refrigerant fluid being selected to give the desired temperature lift without the pressure at the compressor outlet exceeding 25 bar.

Abstract: Rotor for a screw compressor includes a rotor body (2) and a shaft (6), whereby said shaft extends at least with a part into or through a central or approximately central axial bored hole or passage (5) in the rotor body (2). The shaft (6) has a stretch element (7), whereby the rotor body (2) or at least a part thereof is held on the shaft (6) by means of tension elements (11 and 12) which are locked or can be locked axially with respect to the shaft and which are connected with each other by means of the stretch element (7).

Abstract: The invention relates to a dry-compressing dual-shaft rotary displacement screw spindle pump machine for delivering and compressing gases. The spindle rotor pair therein includes multiple stages, having a primary delivery thread, a secondary delivery thread and a gas outlet collector chamber therebetween. The primary delivery thread head circle diameter decreases in the gas outlet direction, while the foot circle diameter thereof increases correspondingly for an application-specific matching inner “integral” compression ratio. The secondary delivery thread nominal delivery direction is opposite to the primary delivery thread nominal delivery direction. The secondary delivery thread is implemented such that the actual gas flow direction is opposite to the nominal delivery direction thereof, and is always directed away from the gas outlet plenum, having a gas permeation under ambient pressure just as the space in the gearbox.

Abstract: The present disclosure relates to fluid machines, especially compressors, more especially screw compressors. More particularly the present disclosure describes a fluid machine comprising at least one rotor (64), the rotor including a rotor drive shaft (68) extending from the rotor, a housing in which is mounted the rotor, and at least one bearing insert (74) which mounts around the rotor drive shaft at a first end of the rotor and which includes at least one bearing (114) within it and attaches to the housing. The present disclosure also describes bearing inserts suitable for use on such fluid machines.

Abstract: A screw compressor includes a screw rotor having a plurality of helical grooves, a casing containing the screw rotor and a gate rotor. The casing includes a discharge port on an inner peripheral surface of the casing. The gate rotor has gates meshing with the helical grooves of the screw rotor to compress gas in compression chambers to discharge the gas from the discharge port after being compressed. The compression chambers are defined by the helical grooves, the casing, and the gates. The discharge port is divided into a first port and a second port when two adjacent helical grooves of the plurality of helical grooves is open to the discharge port as a result of rotation of the screw rotor, with one of the two adjacent helical grooves being open in the first port and the other of the two adjacent helical grooves being open in the second port.

Abstract: Provided is a screw compressor, accommodating a pair of rotatable male and female screw rotors in a compression chamber formed in a casing, wherein the casing includes: an internal dividing wall that defines an inside interior space; and an outer wall that defines an outside interior space arranged outside the inside interior space The screw compressor further includes: a communication pipe member that penetrates the outer wall and extends across the outside interior space, and an end of the communication pipe member being inserted into the internal dividing wall so that the inside interior space communicates with a passage outside the outer wall. By using this communication pipe member, fluid can pass across an interior space in the casing to be fed to another interior space formed further inside.

Abstract: A screw pump includes a stator having a fluid inlet and a fluid outlet, the stator housing first and second externally threaded, tapered rotors mounted on respective shafts and adapted for counter-rotation within the stator to compress fluid passing from the fluid inlet to the fluid outlet, wherein the threads have a pitch that increases towards the fluid outlet.

Abstract: A screw expander system has a condenser positioned for receiving a mixture of oil and operating medium from a screw expander. A pump pressure-feeds the mixture from the condenser to an evaporator where the operating medium is evaporated. An oil separating tank separates the mixture from the evaporator into the gaseous operating medium and the oil, and the operating medium is returned to the screw expander via a throttle mechanism. The oil can thereby be supplied to the screw expander without providing a separate oil pump, as a result of which the screw expander system is compact.

Abstract: A helical gear pump includes a second helical gear provided coaxially with a drive helical gear, a third helical gear engaged with the second helical gear and provided on a third shaft different from a shaft of the drive helical gear and a shaft of a driven helical gear, and a bearing for supporting the third shaft and receiving a thrust force.

Abstract: A Brayton cycle internal combustion engine of the open, or constant pressure type, in which rotary power is produced by the pressure of hot gasses against confined, rotor protrusions.