Abstract: A screw pump (20) with field refurbishment provisions has screws (40), a base (26), and shafts (50) for the screws (40). The screws (40) have helical flights that intermesh during rotation, and extend between inner and outer ends (44 and 42). The shafts (50) extend between inner and outer ends (68 and 74), and are cantilevered from the base (26) from about the inner end (68) thereof. Each screw (40) is formed with a hollow core (80) for receiving its shaft (50) such that the screw (40) slips onto the respective shaft (50) therefor over the outer end (74) of its shaft (50). The screw pump further includes a keyless locking mechanism (56, 58, 96, or 98) intermediate each shaft (50) and screw (40), which is operative to rotationally lock the shaft (50) and screw (40) together without a key or keyway.

Abstract: A moving or progressive cavity motor or pump is disclosed, the motor including a rotor and a stator, the stator having one or more inserts or gearing sections to limit a lateral movement of the rotor relative to the stator. In some embodiments, the motor or pump may include a rotor and a stator, the stator including: a first, helicoidal, section comprising a compliant material having a first compressibility; a second section, helicoidal, non-helicoidal, or combination thereof, having a second compressibility, wherein the second compressibility is less than the first compressibility.

Abstract: A water injection type screw compressor wherein gas sucked from an intake flow is supplied to a rotor chamber, compressed and discharged into a discharge channel as compressed fluid together with water supplied to the rotor chamber, comprises a water separator disposed in the discharge channel to separate water and gas from compressed fluid, a water channel connecting the water separator to a compressor main body for supplying the rotor chamber with the water separated in the water separator, and an oil circulation channel including an oil pump, an oil filter, and a housing for storing oil for supplying the oil to where lubrication is needed. Further, a part of the water channel is arranged passing through an oil trap formed at the bottom inside the housing for storing oil. Thus, oil temperature increases can be minimized in simplified structure having no oil cooling means such as an oil cooler.

Abstract: In order to improve a screw compressor comprising a screw compressor housing having a screw rotor housing, screw rotor bores arranged in the screw rotor housing, screw rotors arranged in the screw rotor bores and mounted in the screw rotor housing for rotation about rotational axes, a drive for the screw rotors, and a slider which is guided for displacement in a slider receptacle in the screw rotor housing and is, in areas, in adjacent relation to the screw rotors with end faces, for adjusting a volume ratio of the screw compressor and which, starting from an insertion space of the slider receptacle, extends in a direction towards the high-pressure outlet in a guide trough of the slider receptacle that is open towards the screw rotor bores and which is capable of being positioned in a first position and a second position, wherein the volume ratio of the screw compressor is greater in one of the positions than in the other of the positions, in such a manner that it requires as small an installation space as po

Abstract: A screw compressor includes a screw rotor, a gate rotor and an injection mechanism. The screw rotor is provided with multiple helical grooves. The gate rotor is provided with multiple gates meshing with the helical grooves to form at least one compression chamber between at least one of the helical grooves and at least one of the gates. The compression chamber is configured and arranged such that refrigerant taken-in from a starting-end side of the helical groove is compressed and discharged from a dead-end side of the helical groove. The injection mechanism is configured and arranged to inject oil or refrigerant from a discharge hole of the injection mechanism into the compression chamber such that rotational torque is imparted in a direction in which the screw rotor is rotated at a time of compression.

Abstract: Screw compressor (1) comprising: a male (2) and a female rotor (3) rotating respectively around a first axis (01) and second axis (02) of rotation, said rotors (2;3) showing, in cross section, meshing lobes (4) and valleys (6) and having profiles generated by enveloping a rack profile (p) including a first curve (z1) of the rack profile (p) extending between a first point (H) and a second point (Q) in a Cartesian reference frame (X, Y) and having a convexity in the positive direction of the axis of abscissa (X), said first point (H) lying on the axis of abscissa (X) at a distance from an origin (0) of the Cartesian reference frame (X, Y) equal to an addendum (hi) of the male rotor (2).

Abstract: A multi-stage oil-free screw compressor includes: a suction throttle valve for controlling air intake into the compressor; a piston assembly for operating the suction throttle valve; and a structure for supplying a working pressure to the piston assembly. In order to reduce startup load at the time of startup of the compressor, the suction throttle valve is fully closed while a secondary side of a compressor body is opened to the atmosphere. When a negative pressure and the air pressure, that provide the working pressure, are used for slightly opening the suction throttle valve in order to switch the compressor to a loaded mode after a motor for driving the compressor is accelerated to its top speed, the air pressure is provided by a control pipe line that is defined by the same pipe line that forms a drain pipe line. This permits the control pipe line to be opened to the atmosphere as needed during the startup time. Thus is provided the oil-free screw compressor achieving improved startup reliability.

Abstract: A progressing cavity pump/motor (10) includes a stator housing (12), a polymeric layer (14), and a rotor (16). A plurality of axially extending grooves (24) are formed in the interior surface of the stator housing for receiving polymeric material therein. At least one seal gland (46) adjacent an end of the polymeric layer maintains sealing between the stator housing and the polymeric layer.

Abstract: A multi-stage oil-free screw compressor includes: a suction throttle valve for controlling air intake into the compressor; a piston assembly for operating the suction throttle valve; and a structure for supplying a working pressure to the piston assembly. In order to reduce startup load at the time of startup of the compressor, the suction throttle valve is fully closed while a secondary side of a compressor body is opened to the atmosphere. When a negative pressure and the air pressure, that provide the working pressure, are used for slightly opening the suction throttle valve in order to switch the compressor to a loaded mode after a motor for driving the compressor is accelerated to its top speed, the air pressure is provided by a control pipe line that is defined by the same pipe line that forms a drain pipe line. This permits the control pipe line to be opened to the atmosphere as needed during the startup time. Thus is provided the oil-free screw compressor achieving improved startup reliability.

Abstract: A system is provided for controlling the balance piston pressure in a screw compressor. The system can use the slide valve of the compressor as a valve to control the flow of fluid from a fluid source to the balance piston. When the slide valve prevents direct flow between the fluid source and the balance piston, an alternate path is used to provide fluid at a reduced pressure to the balance piston. The reduced pressure fluid is obtained by passing the fluid from the fluid source through an orifice to lower the fluid pressure.

Abstract: Designs for multiple segment lobe pumps are shown. The designs include pumps using rotors having two lobes to a plurality of lobes and segments that include two segments to a plurality of segments. Designs for both vertical or straight walled conventional lobed rotors as well as helical lobe rotors are shown. The designs are applicable to a variety of rotors and number of segments. In one particular case the designs enable a three lobe helical pump.

Abstract: A screw compressor includes a pair of rotors housed in a rotor chamber. A gas sucked from an intake channel is compressed by the screw rotors and discharged from a discharge channel. A columnar space having a functional end face with an opening into an intermediate pressure section, which is an empty space in the rotor chamber and isolatable from both the intake channel and the discharge channel by the screw rotors. The functional end face has an opening into a bypass channel in communication with the discharge channel. A piston, inserted in the columnar space and brought into contact with the functional end face, separates the intermediate pressure section from the bypass channel when the piston contacts the functional end face. A pressure detection channel allows an area located on an opposite side of the functional end face in the columnar space to communicate with the discharge channel.

Abstract: An internal combustion engine is provided. The engine comprises at least one combustion chamber. The engine is suitable for various types of fuel. The engine, depending on fuel type, may have at least one spark plug. The engine uses an external source of compressed oxidant, such as air, which is delivered from a compressor and/or pressurized storage tank. Compressed oxidant, such as air, is delivered directly into the combustion chamber. Fuel is delivered directly into the combustion chamber. Oxidant and fuel mixture is ignited either by means of a spark plug, laser ignition, or by other means, or ignites spontaneously, depending on fuel type and pressure in the combustion chamber. The engine may comprise at least one cylinder, or may be of rotary or other type. A hybrid vehicle based on such an engine is provided. An automatic parking system for such a vehicle is provided.

Abstract: A screw vacuum pump, in particular for compression against atmospheric pressure, comprises a pump housing defining a suction chamber. Two meshing screw rotors are arranged in the suction chamber. Further, an overpressure outlet provided, which comprises an overpressure opening in a side wall of the suction chamber. Further, an overpressure valve is arranged in the overpressure outlet. The width (b) of the overpressure opening in the longitudinal direction of the screw rotors is smaller than or equal to a tooth width (B) of the screw rotors.

Abstract: A pump rotor for a screw pump includes a shaft, a first set of threads disposed on a portion of an outer surface of the shaft, at least one thread of the first set of threads including a groove disposed on an end portion thereof, and a ring seal disposed on the groove such that the ring seal is configured to protrude outwardly from the groove and to rest against an inner surface of a liner of the screw pump, and the groove is sized so as to allow the ring seal to move radially with respect to the plurality of threads as the rotor is deflected.

Abstract: A screw compressor includes a screw rotor, a casing, a low pressure space, a bypass passage and a slide valve. The screw rotor is provided with a plurality of helical grooves forming fluid chambers. The casing includes a cylinder portion with the screw rotor disposed in the cylinder portion. The low pressure space is formed in the casing to receive a flow of uncompressed, low pressure fluid. The bypass passage is opened in an inner peripheral surface of the cylinder portion to communicate the fluid chamber with the low pressure space. The slide valve is slideable in an axial direction of the screw rotor to change an area of an opening of the bypass passage in the inner peripheral surface of the cylinder portion. An end face of the slide valve facing the bypass passage is inclined along an extending direction of the helical grooves.

Abstract: A screw fluid machine has a first non-contact seal, a second non-contact seal and a lip seal disposed between a rotor chamber and a bearing for a rotor shaft located on the high pressure side, and in this order from the rotor chamber side. It includes a pressurized communicating channel for introducing high-pressure target gas into a pressurized space formed between the first and second non-contact seals, a pressurized pressure detecting device for detecting the pressure of the pressurized space, and an alarm device for generating an alarm when a value detected by the pressurized pressure detecting device falls out of a predefined range of pressurized pressures. The screw fluid machine is capable of detecting or predicting a condition of the shaft sealing device and accurately and reliably reporting the detected condition to an operator.

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 supercharger cooling system provides a path for coolant from an air/coolant heat exchanger to a supercharger intercooler and loops around a hot outlet end of a screw type supercharger and back to the heat exchanger. The heat exchanger may be a dedicated air/coolant heat exchanger or be a vehicle radiator. The intercooler is sandwiched between the supercharger and intake manifold and cools the flow of hot compressed air from the supercharger into the intake manifold. The supercharger cooling loop circles the front rotor bearings thereby cooling the bearings and seals, the forward ends of the male and female rotors, and the male and female rotor gears. The cooling loop is preferably located in the outlet end wall between the supercharger rotors and the rotor drive gears to form a barrier to heat. A dedicated pump cycles the coolant flow and restrictions control the flow of coolant to the supercharger.

Abstract: A water-lubrication type screw fluid machine has a first non-contact seal, a second non-contact seal and a lip seal disposed between a rotor chamber and a bearing for a rotor shaft. The bearing is located on the high pressure side and in this order from the rotor chamber side. the bearing includes a low pressure communicating channel for allowing an outflow space formed on the rotor chamber side with respect to the first non-contact seal to communicate with a low pressure channel for the target gas communicating with a low pressure space inside the rotor chamber or the rotor chamber, a pressurized communicating channel for introducing high-pressure target gas into a pressurized space formed between the first and second non-contact seals, and an open communicating channel through which an open space formed between the second non-contact seal and the lip seal opens to the outside of the casing.

Abstract: A single-screw compressor includes a casing, a screw rotor accommodated in the casing, a gate rotor, and a gate rotor supporting member rotatably supporting the gate rotor. The gate rotor includes a plurality of flat-plate-shaped gates formed in a radial pattern and meshing with a helical groove of the screw rotor. Fluid in a compression chamber defined by the screw rotor, the casing and the gates is compressed when the screw rotor is rotated. The gate rotor supporting member includes a gate supporting portion supporting each gate from a back surface side. The gate rotor and the gate rotor supporting member form a gate rotor assembly including a pressure introduction channel configured and arranged to introduce a fluid pressure on a front surface side of each gate into a gap between a back surface of the gate and the gate supporting portion.

Abstract: In a screw compression apparatus in which shaft sealing members (13, 14) isolate a bearing space (7, 8) from a rotor chamber (5) and a lubricating fluid separating collector (3) separates the rotor lubricating fluid from the target gas discharged by the screw compressor (2), rotor lubricating fluid separated by the lubricating fluid separating collector (3) is introduced into the rotor chamber (5) via a rotor lubricating flow channel (25), and a bearing lubricating system (17) supplies a bearing lubricating fluid to the bearing space (7, 8). The bearing lubricating fluid flowing out from the bearing space (7, 8) is cooled and returned to the bearing space (7,8). A part of the target gas may be supplied to the shaft sealing members (13, 14) at a location between carbon rings of the shaft sealing members.

Abstract: The present invention provides a dry pump including: a center cylinder which includes: a plurality of pump chambers containing an upper stage pump chamber that communicates with an intake port and a lower stage pump chamber that communicates with a discharge port; a plurality of rotors contained in the plurality of the pump chambers; a rotating shaft that is a rotation axis of the rotor; and a side face on which a communication hole is formed, the side face being intersected by the rotating shaft extending in the axial direction, and being provided adjacent to the lower stage pump chamber, and a side cover which covers the side face with the communication hole to form a space.

Abstract: In order to improve a screw compressor comprising an outer housing, a compressor screw housing which is arranged in the outer housing and in which rotor bores for screw rotors are arranged, a drive arranged in the outer housing on one side of the compressor screw housing, a bearing housing arranged in the outer housing on a side of the compressor screw housing located opposite the drive and a sound damping device which is arranged within the outer housing and has compressed working medium flowing through it, in such a manner that the working medium leaving the screw compressor carries as little lubricant as possible along with it, it is suggested that the sound damping device guide the compressed working medium by means of a flow guide in an interior space as a circulating flow circulating around an axis and that lubricant be separated from the circulating flow of the working medium as a result of centrifugal forces.

Abstract: A screw rotor is for a screw type vacuum pump, preferably for a screw type vacuum pump having a pumping capacity less than 50 m3/h. The rotor has a rotor shaft, a rotor core which rests on the rotor shaft, and a rotor cover which rests on the rotor core and at least partially encloses the rotor core. The rotor core is made of a material having a thermal conductivity greater than 100 W/m·K, preferably a thermal conductivity greater than 200 W/m·K. A screw type vacuum pump has correspondingly designed rotors.

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 screw compressor has a balance bearing whose outer ring is movable relative to the casing. A balance piston divides a balance cylinder into a high pressure fluid chamber and a low pressure fluid chamber, and movement of the piston in the balance cylinder is transmitted to the outer ring of the balance bearing. The high pressure fluid chamber and the low pressure fluid chamber are arranged such that higher pressure fluid in the high pressure fluid chamber urges the piston to press the outer ring of the balance bearing oppositely to a spring and toward the main thrust bearing, and lower pressure fluid in the low pressure fluid chamber urges the piston to press the outer ring of the balance bearing away from the main thrust bearing.

Abstract: A compressor system includes a lubricant reservoir, a screw compressor, and a valve. The screw compressor includes a housing defining a compression chamber having a suction port, a discharge port, a first lubricant feed port located between the suction port and the discharge port, and a second lubricant feed port located between the discharge port and the first lubricant feed port. The valve is in fluid communication with the lubricant reservoir, the first lubricant feed port via a first lubricant feed passageway, and the second lubricant feed port via a second lubricant feed passageway. The valve is movable between a first position and a second position. In the first position, the valve fluidly connects the lubricant reservoir to the first lubricant feed passageway to direct lubricant to the first lubricant feed port. In the second position, the valve fluidly connects the lubricant reservoir to the second lubricant feed passageway to direct lubricant to the second lubricant feed port.

Abstract: A two-stage medium-pressure screw air compressor comprises a primary screw compressor (21) and a secondary screw compressor (22) communicating with the gas-liquid separator (6) via the first gas-liquid inlet (61). A first oil outlet (63) is connected to a mid section of a gas-liquid separator (6). The oil is injected into the lubricating components of the compressor is the first oil outlet (63), a first filter (64). A secondary oil-water separator (9) is connected to the first oil outlet (63) of the gas-liquid separator (6), the second oil-water separator (6) has an upper separating tank (91) and a lower separating tank. The water and the impurities contained in the lubricating oil can be eliminated at a largest extent, so as to create essential condition thr ensuring the screw compressor to operate continuously, stably and safely and provide high operational reliability, safety and long service life.

Abstract: A screw compressor (10) is provided with shaft seal sections (28, 41) located on opposite sides of a compression chamber (24) of a screw rotor (25), to prevent mixing of oil in bearings (27, 39, 40) into the compression chamber (24) and leakage of process gas from the compression chamber (24). A suction-opening return line (52) interconnects the shaft seal section (41) on the discharge side of the compression chamber (24) and a suction opening (17) of the compressor body (11). A supply-process-gas communicating line (61) interconnects the suction opening (17) of the compressor body (11) and the upper part of the oil supply tank (13), and a shaft seal section (53) divides the inside of the compressor body (11) and an atmospheric environment.

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: A variable capacity screw compressor for use in a refrigeration system is provided. Compressed refrigerant gas from the compressor is expelled into a discharge port in fluid communication with the refrigeration circuit. The volume associated with the discharge port can be periodically varied, allowing the efficiency of the compressor to be varied periodically. The discharge port volume includes a penetration that houses a movable member or plug that permits the volume to be periodically varied. This movable member is accessible from the exterior of the compressor housing to adjust the position of the movable member within the discharge port volume. The movable member may be adjusted to a full open position in which the discharge port volume is maximized, to a full closed position in which the discharge port volume is minimized, and to any position between full open and full closed.

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 screw vacuum pump includes a male rotor, a female rotor, a stator, and a drive motor/motors. A screw gear portion of the male rotor, a screw gear portion of the female rotor, and the stator cooperatively form a gas working chamber. The stator has an inlet port and an outlet port. At least one of the male rotor and the female rotor has a rotor hollow portion which is opened on at least one end face side in a rotation-axis longitudinal direction of the male rotor and/or the female rotor. The drive motor is at least partially received in the rotor hollow portion.

Abstract: A screw machine for use with a working fluid with a liquid phase present comprises rotors having meshed, lubricated helical formations. The rotors have an ‘N’ profile as disclosed in WO 97/43550. In use, lubrication of the helical formations of the rotors and optionally of the rotor bearings is achieved substantially exclusively with the liquid phase of the working fluid.

Abstract: A screw compressor includes a screw rotor, a gate rotor, a drive mechanism to rotate the screw rotor, a cylinder, a discharge port and an adjustment mechanism. The screw rotor has an outer periphery with a helical groove engaged with radially arranged gates of the gate rotor. First and second axial ends of the screw rotor form suction and discharge sides, respectively. The cylinder accommodates the screw rotor to define a compression chamber in the helical groove. Fluid in the coin cession chamber flows through the discharge port toward the discharge side of the screw rotor. The adjustment mechanism is configured to adjust a compression ratio of the compression chamber within a predetermined. range. The adjustment mechanism adjusts the compression ratio to a minimum compression ratio immediately before or when operation of the adjustment mechanism is stopped.

Abstract: The invention relates to a multi step helical screw compressor unit which consists of a drive housing (90), wherein a first, second, and third helical screw compressor (60, 70, 80) are secured in a protruding manner parallel to each other and are driven together by a drive toothed wheel in the drive housing. A gas-like fluid is compressed by the first helical screw compressor (60) at a first intermediate pressure of approximately 3.5 bars, by the second helical screw compressor (70) at a second intermediate pressure of approximately 12 bars and by the third helical screw compressor (80) at an end pressure of approximately 40 bars. The driven toothed wheels (65, 75) of the first and the second helical screw compressors are in contact with the drive toothed wheel (95) above the axes thereof, when the driven toothed wheel (85) of the third helical screw compressor (80) is in contact with the drive toothed wheel (95) in the vicinity of the deepest point thereof (T).

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: An oval gear set for use in a flow meter comprises first and second gears that are identical to each other and that are configured to engage at a fixed center-to-center distance such that the first and second gears mesh at all angular positions. Each gear of the oval gear set comprises a hub and a plurality of gear teeth. The hub comprises an oval body having a major axis and a minor axis extending through a center of the hub, and a root profile wall circumscribing the major and minor axes. The plurality of gear teeth extend from the root profile wall. Each of the gear teeth has a pair of contact surfaces with circular involute curve profiles.

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 screw spindle machine having a tubular casing (10) that is made of cast metal and is lined with a wear resistant layer (16), with the wear resistant layer (16) being encapsulated in a steel shell (20) that matches the outer peripheral shape of the layer (16).

Abstract: A groove is provided in the periphery of a pressure receiving area of a pressure receiving surface opposing to the load of axis weight within a bearing surface supporting an axis, and a liquid supply route communicating with the groove is provided so that liquid is supplied to the groove through the liquid supply route. In such a configuration, a bearing having a simple structure and a high compact load capacity and a liquid cooling type screw compressor using the above bearing are provided.

Abstract: The present invention is to provide a screw rotor including a resin rotor formed around a metallic shaft without generation of cracks. Spiral chamfers are formed on surfaces of metallic shafts around which resin rotors are formed. Preferably the surfaces of the shafts may be sandblasted, and after the surfaces of the shafts are preliminarily coated with resin and then the rotors may be molded.

Abstract: A compressor including a compression mechanism configured and positioned to receive vapor from an intake passage and provide compressed vapor to a discharge passage. An opening is positioned in the compression mechanism in fluid communication with the discharge passage. A valve has an aperture formed therein, the aperture configured and positioned in fluid communication with a passageway to provide a path for a pressurized vapor flow to a first chamber and a first piston without mixing with vapor in the discharge passage. A second chamber is in fluid communication with a second piston and the discharge passage, the first piston and the second piston of the valve configured to move together. First piston and second piston movement are controllable in response to predetermined conditions to maintain the magnitude of pressure of the compression mechanism immediately upstream of the opening at substantially the same pressure magnitude at the discharge passage.

Abstract: An oil-cooled type screw compressor includes shafts mounted on rotors in a casing and extended to two sides of the rotors. Thrust plates rotate with the shafts. The thrust plates are sealed while spacing them from the rotors and define first and second spaces. Thrust bearings are arranged in the first and second spaces. An oil feed passage communicates with the one of the first and second spaces that is located on the side to apply a force against the thrust force to the thrust plates when boosted. An oil discharge passage communicates with the one of the first and second spaces that is located on the side to apply a force against the anti-thrust force to the thrust plates when boosted, to establish the communication between the space inside and an oil discharge target. An oil distribution passage distributes oil between the first space and the second space.

Abstract: A single-screw compressor includes a screw rotor, a cylinder wall in which the screw rotor is rotatably accommodated, a driving mechanism which variably drives the screw rotor according to a load, and a slide valve which is provided in a slide groove formed in the cylinder wall. The slide valve faces an outer circumferential surface of the screw rotor to be movable in an axial direction, and to adjust a discharge start position by being moved in the axial direction according to the operating capacity. A discharge side end surface of the slide valve extends in a direction corresponding to a screw land of the screw rotor to which the discharge side end surface faces when the slide valve is moved to a position corresponding to a part load operation state.

Abstract: A braking controller of a three-phase permanent magnetic brushless DC motor for directly driving a screw pump includes a detection circuit for detecting power supply states of the three-phase permanent magnetic brushless DC motor and a braking circuit for controlling the braking startup according to the power supply states of the three-phase permanent magnetic brushless DC motor. When the motor is supplied with power, the braking circuit is cut off. When the motor is not supplied with power and the screw pump drives the motor to reverse, the braking circuit starts up.

Abstract: A screw compressor comprising: a low pressure stage compressor body; a high pressure stage compressor body that further compresses a compressed air compressed by the low pressure stage compressor body; pinion gears for example, respectively, provided on, for example, a male rotor of the low pressure stage compressor body and, for example, a male rotor of the high pressure stage compressor body; a motor; a bull gear for example, provided on a rotating shaft of the motor; and an intermediate shaft supported rotatably and provided with a pinion gear, which meshes with the bull gear, and a bull gear, which meshes with the pinion gears. Thereby, it is possible to make the motor relatively low in rotating speed while inhibiting the gears from being increased in diameter, thus enabling achieving reduction in cost.

Abstract: A two-stage screw compressor has a low-pressure stage screw compressor and a high-pressure stage screw compressor integrally constructed. Compression space is formed by a male rotor and a female rotor, and operation gas is fed for compression to the compression space. A method of supplying lubrication oil 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. As a result, refrigeration capacity is improved and the amount of the lubrication oil is reduced.

Abstract: A screw expander system includes a screw expander provided with an expansion space for expanding an operating medium, an operating medium inlet, an operating medium outlet, oil inlets, and oil outlets, a condenser which condenses a mixture, sent from the screw expander, of oil and the operating medium, a pump which pressure-feeds the mixture sent from the condenser, and an evaporator which evaporates the operating medium contained in the mixture. The screw expander system circulates and supplies the operating medium sent from the evaporator, to the operating medium inlet, and circulates and supplies the oil sent from the evaporator, to the oil inlets. An oil separating tank which separates the mixture into the operating medium and the oil is disposed between the evaporator and the screw expander, and an oil containing section of the oil separating tank and the oil inlets of the screw expander are connected.