Abstract: A screw displacement pump is provided. The screw displacement pump is of single-entry, double-shaft construction with an external bearing of the two screw shafts. A pump housing encloses the screw shafts by forming feed chambers and externally delimiting the feed chambers with its internal shell surface, as well as a suction chamber for the medium to be induced and a pressure chamber to accommodate the medium pumped by the screw shafts. The pump housing is inserted into a pressure housing and attached to the pressure housing, so that the pressure chamber encloses the pump, at least in part.

Abstract: Provided is an oil-cooled type screw compressor having a compressor body for compressing a suction gas and discharging the compressed gas.

Abstract: The invention revealed a screw compressor and its electrical control system and related control methods. The system comprises a power module, a high-low (tension) transformer and a compressor wiring control circuit. The high-low (tension) transformer connects the power module to provide at least two different voltages: low voltage and high voltage; the compressor wiring control circuit connects said high-low (tension) transformer to control the switching and connection mode of said wiring terminals of the compressor; When the first voltage is connected to the screw compressor, the connecting circuit formed by the wiring terminals which are controlled by a connecting unit will be in the first status. When the second voltage is connected to the screw compressor, the connecting circuit formed by the wiring terminals which are controlled by a connecting unit will be in the second status.

Abstract: A screw compressor includes a housing, a motor stator, a motor rotor, a helical screw rotor, a motor rotor stop, a screw fastener, and a third bearing. The helical screw rotor includes an extension section, a motor coupling section, a first supporting section, a helical screw section, and a second supporting section. The motor rotor stop includes two flange portions, wherein one flange portion is sleeved with the extension section and abuts axially upon the effective sensing section of the motor rotor. The third bearing is interposed between the other flange portion and the housing cap. The screw fastener extends through the motor rotor stop and is threadedly engaged into a thread hole of the helical screw rotor and then biases axially upon the motor rotor stop. Therefore, the motor rotor is secured more firmly, and that a compressor shaft maintains a stable running.

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: Low-pressure screw compressor provided with a rotor housing (2) with an inlet side and an outlet side, and enclosing two rotor bodies (3 and 4) including shafts (5, 7 respectively) and screws (6, 8 respectively) mounted on the shafts. The rotor shafts (5 or 7) are bearing-mounted in the rotor housing (2), with the bearing mountings on the inlet side of the rotor housing each using a single loose bearing and the bearing mountings on the outlet side of the rotor housing each using a single fixed cylindrical roller bearing. Spring devices acting on the bearing mountings at the inlet side urge the shafts and rotors toward the outlet side to maintain minimum clearance between the rotors and the housing at the outlet side of the rotors.

Abstract: A fluid pump (10) or motor (100) includes a pair of enmeshed tapered rotors (22,24,122,124) having intersecting axes of rotation. The first rotor (22,122) includes a small low pressure end (34,54,134,154) and a larger high pressure end (32,52,132,152) and a spiral thread (36,56,136,156) that increases in width and depth as it progresses from the high pressure end (28,128) to the low pressure end (26,126). The second rotor (24,124) enmeshes with the first rotor (22,122), and has an identical structure, except that its threads (36,56,136,156) progress in the opposite direction. Both rotors (22,24,122,124) are mounted on sliding splines (42,62,142,162) which permit them to move, to a limited extent, into and out of their respective receiving cavities.

Abstract: A pump having a rotor, a stator, a housing enclosing the rotor and the stator, the housing having an inlet for a fluid, and a port for receiving a fluid which acts on deposits on a surface of the rotor and on a surface of the stator positioned downstream from the inlet.

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 solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Abstract: In an oil-cooled screw compressor comprising, a compressor body including a pair of a male rotor and a female rotor, a motor including a stator and a motor rotor connected to one of the male and female rotors, and an oil separator container for gathering the oil from a mixture of the gaseous manner and oil to restrain the oil from proceeding with the compressed gaseous matter after the mixture of the gaseous manner and oil is discharged from the pair of male and female rotors, a rotational axis of the motor rotor and the rotational axis of the one of the male and female rotors are coaxial with respect to each other.

Abstract: In order to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability, the screw compressor comprises a screw rotor, a low-pressure-side bearing and a high-pressure-side bearing which support the screw rotor, a motor which drives the screw rotor, a motor casing which accommodates the motor, a main casing which accommodates the screw rotor and the low-pressure-side bearing, and a discharge casing which accommodates the high-pressure-side bearing. The motor casing, the main casing, and the discharge casing are accommodated in a steel pipe chamber, and the steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in the axial direction. By using a flange provided on an inner surface of the steel pipe chamber, a flange provided in the main casing, and a sealing component provided between the flanges, the steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space.

Abstract: A compressor is provided with a substantially cylindrical housing. Inside the housing is a motor housing having a substantially cylindrical shape and a compressor housing having a substantially cylindrical shape. The motor housing and the compressor housing are connected or fit into the housing with a frictional connection to prevent axial movement of the motor housing and the compressor housing.

Abstract: A compressor includes a male rotor (26) having a screw-type boy portion (30) extending from a first end (31) to a second end (32) and held within a housing assembly for rotation about a first rotor axis (500). A female rotor (27, 28) has a screw-type female body portion (33, 34) meshed with the male body portion and extending from a first end (35, 36) to a second end (37, 38) and held within the housing assembly for rotation about a second rotor axis (501, 502). An end seal (120) has a first surface (126) engaging the female body portion first end and being asymmetric around the second axis.

Abstract: A cross section of a tooth profile of a first screw rotor (17) perpendicular to the rotor axis includes a tooth top arc (A1B1), a tooth bottom arc (C1D1), a first curve (A1C1), and a second curve (B1D1). The first curve (A1C1) is a first trochoidal curve that connects a first end (A1) of the tooth top arc (A1B1) to a second end (C1) of the tooth bottom arc (C1D1). The second curve (B1D1) connects the second end (B1) of the tooth top arc (A1B1) to the first end (D1) of the tooth bottom arc (C1D1). The second curve (B1D1) is a composite curve formed by an involute curve (B1E1) and a second trochoidal curve (E1D1), which extend continuously from each other at a first intersection point (E1). A screw pump (11) thus suppresses leakage of fluid with improved performance.

Abstract: A compressor (20) has an unloading slide valve (100). The valve has a valve element (102) having a range between a first condition and a second condition, the second condition being unloaded relative to the first condition. A first surface (200) of the valve element (102) is in sliding engagement with a second surface (202) of the housing (22) during movement between the first and second conditions. The compressor includes means for lubricating the first (200) and second (202) surfaces.

Abstract: A compressor includes a casing, a screw rotor fitted in the casing, at least one economizer port, and a control unit. The at least one economizer port is arranged to discharge refrigerant into compression chambers formed between the casing and the screw rotor. The control unit is configured to advance timing of opening of the at least one economizer port to the compression chambers in accordance with increase in rotating speed of the screw rotor.

Abstract: An intake assembly, such as a supercharger assembly, is provided for an internal combustion engine. The intake assembly includes a housing having a wall defining an inlet passage through which intake air enters the intake assembly. A plurality of stiffening ribs is provided on the wall opposite the inlet passage and at least partially defines at least one cavity. A plate is mounted to the wall of the housing and further defines the at least one cavity. The wall defines at least one orifice configured to provide communication between the inlet passage and the at least one cavity. The at least one cavity and the at least one orifice cooperate to form at least one resonator. A method of forming the intake assembly having integral resonators is also provided.

Abstract: A screw compressor of the present invention includes a pair of male and female screw rotor meshed with each other and rotatably accommodated in a casing, the screw rotors being adapted to suction, compress and discharge a fluid, a main thrust bearing having an inner ring fixed to a rotor shaft serving as a rotation shaft of at least one of the screw rotors and an outer ring fixed to the casing, the main thrust bearing being adapted to receive thrust force of the rotor shaft, a balance bearing having an inner ring fixed to the rotor shaft and an outer ring movable relative to the casing, a bearing holding member for holding the outer ring of the balance bearing, and fluid pressure application means for pressing the bearing holding member toward the discharge side by fluid pressure. With such arrangement, it is possible to reduce a thrust load of the rotor shaft, and eliminate risks of an increase in a rotational load by a balance piston and seal leakage of the balance piston.

Abstract: A rotary pump has a housing composed of two intersecting cylinder sections and pump rotors therein. The rotors roll off on one another and against the interior wall of the housing in a sealing manner and have two approximately club-shaped sections that are connected to each other at their narrower ends via a waisting. The club-shaped section of one rotor engages into the waisting of the other rotor. The rotors create in each phase of the rotation movement an evenly increasing intake volume in front of the inlet port and an evenly decreasing discharge volume in front of the outlet port, provision is made that, in order to improve the pumping performance and increase the stability under load, the surface lines, which function as sealing lines are designed sine shaped.

Abstract: A plurality of scroll compressors with different fixed volume indexes are connected in fluid parallel circuit and configured to selectively operate to maximize isentropic efficiency at different condensing temperatures. Different quantities of scroll compressors of different volume indexes may be selected based upon typical climate or geographic location environmental conditions to attempt to maximize efficiency. A controller may selectively operate different combinations of the compressors of different volume indexes bases up load demands and condensing temperature conditions, which may be determined in a variety of ways.

Abstract: In an oil-cooled screw compressor comprising, a compressor body including a pair of a male rotor and a female rotor, a motor including a stator and a motor rotor connected to one of the male and female rotors, and an oil separator container for gathering the oil from a mixture of the gaseous manner and oil to restrain the oil from proceeding with the compressed gaseous matter after the mixture of the gaseous manner and oil is discharged from the pair of male and female rotors, a rotational axis of the motor rotor and the rotational axis of the one of the male and female rotors are coaxial with respect to each other.

Abstract: A single screw compressor structure includes a screw rotor and a casing, which houses the screw rotor. A tapered outer circumferential surface of the screw rotor has a plurality of helical grooves, with an outer diameter that increases from an inlet side toward a discharge side. The casing includes an outer tube member having a circular inner hole to form an interior, and an inner tube member is fixed to the interior of the outer tube member. The inner tube member has a tapered inner surface that opposes the tapered outer circumferential surface of the screw rotor. A single screw compressor further including a gate rotor is assembled mesh between the screw rotor and the gate rotor, aligning the tapered outer and inner circumferential surfaces relative to one another, and integrally coupling the outer and inner tube members to each other.

Abstract: On screw compressors for extremely high discharge pressures, e.g. for application in refrigeration systems operating with CO2 in a transcritical process, featuring two rotors, a male rotor and a female rotor having a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7, with the male rotor having a drive-shaft end, and both rotors are enclosed in a housing, the wrap angle of the profile section of the male rotor is less than 1.5 the lobe-pitch angle, and the working cycle from the beginning of suction till the end of discharge is less than 600° of the angle of rotation of the male rotor, and the length-to-diameter ratio of the profile section of the male rotor lies between 0.3 and 0.5.

Abstract: An axial flow positive displacement gas turbine engine component such as a compressor or a turbine or an expander includes a rotor assembly extending from a fully axial flow inlet to a downstream axially spaced apart axial flow outlet. The rotor assembly includes a main rotor and one or more gate rotors rotatable about parallel main and gate axes of the main and gate rotors respectively. The main and gate rotors having intermeshed main and gate helical blades extending radially outwardly from annular main and gate hubs, circumscribed about, and wound about the main and gate axes respectively. Intersecting main and gate annular openings in the axial flow inlet extend radially between a casing surrounding the rotor assembly and the main and gate hubs. The main helical blades transition from 0 to a full radial height in a downstream direction in an inlet transition section.

Abstract: In a screw vacuum pump 30, equal lead screws each in the range of 1 to 4 leads are added on the discharge side of male and female screw rotors (4) and (5) having a continuously changing screw gear helix angle, at a final lead angle of the male and female unequal lead screw rotors on the discharge side that continuously change in helix angle following the advance of the screw gear helix.

Abstract: A screw compressor comprising: a pair of male and female screw rotors; and an air-cooled heat exchanger, wherein the air-cooled heat exchanger is provided above a motor for driving the compressor body; wherein, with respect to a cooling wind for the air-cooled heat exchanger, the air-cooled heat exchanger is inclined to the upstream side; wherein the uppermost portion of a unit suction port for the air-cooled heat exchanger cooling winds is positioned below the uppermost portion of the air-cooled heat exchanger positioned at the uppermost portion; wherein the lowermost portion of the unit suction port for the air-cooled heat exchanger cooling wind is positioned below the lowermost portion of the air-cooled heat exchanger positioned at the lowermost portion; and wherein the cooling wind for the air-cooled heat exchanger is exhausted from a ceiling portion of the compressor unit.

Abstract: A method of supplying lubrication oil to a two-stage screw compressor is disclosed in which a low-pressure stage screw compressor and a high-pressure stage screw compressor are integrally constructed. A compression space is formed by a male rotor and a female rotor, and operation gas is fed for compression to the compression space. The method prevents degradation of volumetric efficiency caused by return of lubrication oil, coming from a bearing and a shaft sealing device, to the low-pressure stage screw compressor, and as a result, refrigeration capacity is improved and the amount of the lubrication oil is reduced.

Abstract: In a screw compressor, a pair of rotors are located in a housing to be rotatable around their rotary axes to form in the housing a compression chamber in which gas sucked from a suction port of the housing is compressed thereby discharging the compressed gas from a discharge port of the housing. The suction port is provided in the housing at a position radial outside of the rotors, and the housing is provided with a communication passage through which the suction port communicates with the compression chamber before being communicated with the suction port. Furthermore, the communication passage is provided such that the gas sucked from the suction port flows into the communication passage in a direction approximately parallel with an axial direction of the rotors.

Abstract: A gear compressor or supercharger for compressing compressible fluids such as air, having a pair of intermeshing helical lobed rotors. An aperture is provided on the bottom of the compressor, at a rear end thereof, which permits air from the rear interior of the compressor to be in communication with high pressure supply air which is discharged from such compressor proximate the front of such compressor, on the bottom underside portion thereof. The above modification improves the efficiency of the compressor, particularly at high revolutions.

Abstract: A rotor shaft sealing method for an oil-free rotary compressor is provided, with which occurrence of lubrication oil intrusion into the compression chamber of the compressor which is liable to occur when negative pressure is produced in the compression chamber, is prevented. With a rotor shaft sealing structure composed such that two shaft seal means are provided in the rotor casing between the oil lubricated bearing and the compression chamber such that an annular airspace is formed between the two shaft seal means, at least one communicating hole is provided to communicate the annular airspace to the outside of the rotor casing, and the annular airspace of the male rotor shaft sealing part and the annular airspace of the female rotor shaft sealing part are connected by a between-rotor shaft communication passage, pressurized air is supplied to the annular airspaces by which lubrication oil intrusion into the compression chamber is prevented.

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 rotatable sound attenuation device is provided comprising a central portion rotatable about a first axis, a radial portion extending outwardly from the central portion and a chamber having a closed first end and a second end opening radially outwardly of the radial portion and defining a second axis therein having a radial component thereto. A piston is disposed within the chamber and is moveable to a location along the second axis in response to a centrifugal force imparted on the piston by rotation of the central portion and the radial portion about the first axis. A biasing member operates to limit movement of the piston along the second axis. A quarter wave chamber is defined by the second, open end of the chamber and the piston and has a sound attenuating length defined by the location of the piston along the second axis of the chamber.

Abstract: The invention downsizes and simplifies structures of a compressor and its driving system apparatus, and achieves a reduction of a noise. An oil free screw compressor is constituted by compressor main bodies compressing a gas, a motor driving rotors of the compressor main bodies via step-up gears, a gear casing storing the step-up gears, cooling apparatuses cooling a discharge air and the like. An oil tank is provided independently from the gear casing, the motor is fixed to a common base, the gear casing is integrally attached to the motor via a flange, and the compressor main bodies are integrally attached to the gear casing via the flange. Further, the cooling apparatuses are arranged in an upper side of the driving system apparatus, and a cooling fan is installed in an upper side thereof.

Abstract: An improved geared hydraulic apparatus, comprising a pair of meshing gearwheels, mounted to be reciprocally rotatable in a casing between an inlet side and an outlet side for a fluid having, in use, a substantially transverse flow with respect to the axes of rotation of the gearwheels. The meshing gearwheels create, during their reciprocal rotation, progressive meshing configurations between respective co-operating teeth. In at least one of said progressive meshing configurations is defined, in at least one cross-section of the gearwheels, at least one closed area between respective fluid entrapment teeth. The closed area decreases until it is substantially cancelled out at and around at least one other, separate progressive meshing configuration between the aforesaid respective co-operating teeth.

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: Abstract A shaft seal structure (17) is provided around an outer circumferential surface of the bearing member (16M, 16FM) located on the cylinder inside of each of the screw rotors (13M, 13FM). The shaft seal structure (17) forms a static pressure seal. A seal gas is introduced between the outer circumferential surfaces of the bearing members (16M, 16FM) and the inner circumferential surfaces (7) of the rotor cylinders of the screw rotors (13M, 13FM) through the bearing members (16M, 16FM).

Abstract: A gear drive assembly for a supercharger is provided. The gear drive assembly has at least one gear member rotatable about an axis of rotation and includes a cover member operable to substantially enclose the at least one gear member. A tube member extends though the cover member and is generally aligned along the axis of rotation. The tube member is operable to vent the gear drive assembly. A supercharger assembly incorporating the gear drive assembly is also disclosed.

Abstract: A pump rotor for a screw pump, comprising a shaft, a thread on the shaft, the thread comprising a groove disposed on an outer surface thereof, and a seal disposed in the groove. The seal and the groove are configured to retain the seal in the groove while allowing radial displacement of the seal with respect to the thread as the pump rotor is deflected.

Abstract: A screw pump includes a casing including a main accommodating bore and plural sub accommodating bores, a main rotor adapted to be rotatably accommodated in the main accommodating bore, and plural sub rotors adapted to be respectively rotatably accommodated in the sub accommodating bores. Each sub rotor is adapted to engage the main rotor. A cross sectional shape of a flank surface of the main rotor, which is taken in a direction perpendicular to an axial direction of the main rotor, is formed along an epitrochoid traced by an edge of the sub rotor not to include an undercut shape. Further, a cross sectional shape of a flank surface of each sub rotor, which is taken in a direction perpendicular to an axial direction of the sub rotor, is formed along an epitrochoid traced by an edge of the main rotor not to include an undercut shape.

Abstract: A screw compressor includes a pair of male and female screw rotors which meshes with each other, where a casing storing the pair of screw rotors is divided into a discharge opening neighborhood portion including at least a discharge opening and an other portion other than the discharge opening neighborhood portion, the discharge opening neighborhood portion is configured so as to be removable from the other portion, further, the casing is divided, by two dividing surfaces orthogonal to rotor shafts, into three portions including a rotor casing around the pair of screw rotors, a discharge casing on a side of the discharge opening, and a suction casing on a side of a suction opening, and the discharge opening neighborhood portion is formed by dividing the rotor casing, and is configured so as to be removable from the dividing surface on the side of the discharge opening of a divided rotor casing.

Abstract: A compressor includes a screw rotor and a gate rotor. The screw rotor has a plurality of spirally extending groove portions disposed radially outwardly from the center axis of the screw rotor. The gate rotor has a plurality of tooth portions circumferentially arranged on an outer circumference to engage the groove portions. Preferably, an inclination angle of a groove portion side face contacting the tooth portions is inclined relative to a circumferential direction of the gate rotor varies. Alternatively a first plane contains the screw rotor center axis, a second plane orthogonally intersects the screw rotor center axis, a third plane orthogonally intersects the first and second planes, the gate rotor center axis is on the third plane, and the tooth portions do not overlap the first plane as viewed orthogonally relative to the third plane.

Abstract: A screw vacuum pump includes a gas working chamber formed by a male screw rotor and a female screw rotor respectively including unequal lead screws engaging each other and having a lead angle that continuously changes with the advance of helix and a stator receiving therein both rotors. The stator is provided with a gas inlet port and a gas outlet port that can communicate with one end portion and the other end portion of the working chamber, respectively. The male screw rotor and the female screw rotor have unequal lead screws each of which is formed into a perpendicular-to-axis cross-sectional shape that changes following a continuous change in lead angle with the advance of helix. Alternatively, one of the male screw rotor and the female screw rotor has the unequal lead screw formed into a perpendicular-to-axis cross-sectional shape that is constant. Another has the unequal lead screw formed into a perpendicular-to-axis cross-sectional shape that changes.

Abstract: A screw compressor has a housing (22; 302) having first (53; 330) and second (58; 340) ports along a flowpath. A first rotor (26; 306) has a lobed body. A second rotor (28; 308, 310) has a lobed body enmeshed with the first rotor body. The rotors and housing cooperate to define a compression path between suction (60; 332) and discharge (62; 342) locations along the flowpath. Means (100, 110, 120; 200, 210, 220; 370, 380, 390) provide relative longitudinal movement between a blocking portion (57; 352) of the housing and at least one of the first rotor and second rotor between: a first condition wherein a pocket of the first and second rotors is closed by the blocking portion; and a second condition wherein the blocking portion does not close the pocket. To provide capacity control, a control system (110; 390) is configured to provide duty cycle control of the movement.

Abstract: A multi-rotor compressor and method of manufacturing is provided. The compressor includes a housing with a plurality of identical planet rotors. The planet rotors are equally spaced apart at a fixed distance from a centerline. A single sun rotor is provided that is disposed to cooperate with the plurality of identical planet rotors in the compression of gas. The number and radial spacing of the plurality of identical planet rotors about said single sun rotor may be arranged in different configurations to change an output capacity parameter for said compressor.

Abstract: The invention relates to oil-flooded screw compressors having a male rotor and female rotor each featuring preferably a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7. In order to decrease the bearing load at higher working pressures, the profile sections of the rotors are shortened, and an intermediate plate is appropriately arranged in the free space formed.

Abstract: Improved water-injected screw compressor element which mainly consists of a housing (2) on the one hand, confining a rotor chamber (5) with an inlet (6) on one far end and an outlet (7) on the other far end and in which two co-operating rotors (3, 4) are provided which are bearing-mounted in the housing (2) with their shaft (16, 20) by means of water-lubricated bearings (17, 18, 21, 22), characterised in that for every rotor are provided two pistons, a first piston (37, 38) and a second piston (17, 21) respectively, which can be each axially shifted in a guide, whereby each of these pistons (17, 21, 37, 38) makes contact with the rotor (3, 4) concerned with one side or is part of it, and makes contact with a pressure chamber (41, 42, 43, 44) with an opposite side, in order to partly or almost entirely compensate for axial force components exerted by the compressed gasses on the rotors.

Abstract: A positive displacement supercharger includes a housing defining a rotor cavity with a pair of positive displacement rotors operative to carry air axially from an inlet end to an outlet in the cavity wall near an outlet end of the cavity. The outlet communicates with an outlet plenum partially defined by the cavity wall. The cavity wall includes a stiff portion defining a plurality of lightening recesses, such as a waffle pattern, limiting distortion of the wall by pulsations in the plenum. The recesses may be time and cost efficiently converted to Helmholtz tuners by covering the recesses with a cover plate, which may be perforated to include at least one tuning opening (perforation) into each tuning chamber (recess) and forming tuning volumes of the tuning chambers and their associated tuning openings effective to attenuate selected frequencies of pulsations in the plenum and thereby reduce undesired noise emanating from the air system of the supercharger.

Abstract: An improved multi-stage compressor device for compressing gas, which compressor device (1) mainly consists of at least two compressor elements (2-5-28) placed in series one after the other, at least one of which (5-28) is driven by a motor (9), characterized in that at least one other compressor element (2) is driven separately, in other words without any mechanical link with said motor (9), by means of an expander (18) of a closed power cycle (12) with a circulating medium inside which is heated by the compressed gas.

Abstract: A compact helical compressor system for mobile use in vehicles is described. The system includes a helical compressor unit, a motor unit dedicated to the helical compressor unit for driving the helical compressor unit, and a control unit for adjusting a rotational speed of the motor unit and to generate a predefined discharge rate of compressed air from the helical compressor unit, independently of a drive assembly of the vehicle.