Abstract: An apparatus for reducing noise of a gear pump through uneven pitch-simulated control includes a calculation unit to calculate different control current values for each tooth of a teeth order by applying a teeth number, the teeth order, and a teeth angle of the gear pump in which a plurality of teeth are evenly formed, a storage unit to map and store the teeth order and the different control current values corresponding to the teeth order for each tooth, and a current controller to variably generate the control current value mapped corresponding to the teeth order when each tooth reaches a reference position when the gear pump rotates by a motor, wherein the control current value is added to a reference current value of a motor control signal and applied to the motor.

Abstract: A rotary action, self-priming positive displacement constant flow high capacity fluid pump is described. None of the pump parts touch in the pump chamber to minimize pump wear allowing for extended pump life. Since there are no touching parts in the pump chamber, the pump can be operated dry without the pump liquid being present without damage to the pump. The pump may be operated either clockwise or counter-clockwise without loss of positive displacement or reduction in fluids input or output. Due to the design of the pump, the pump is inherently low-maintenance and is highly resistant to clogging by debris and the like. Fluid pressure relief sections are provided by carving out of the inside portions of the housing structure to which the ends of the shaft are mounted to vary or improved pump performance.

Abstract: A shunt pulsation trap for a scroll compressor reduces gas pulsations, NVH and improves off-design efficiency. Generally, a scroll compressor with the shunt pulsation trap has a pair of orbiting and stationary scrolls for forming a compression chamber that moves gas pockets from a suction port to a discharge port with internal compression. The shunt pulsation trap is configured to trap and attenuate as pulsations before the discharge port and comprises a pulsation trap chamber adjacent to the compression chamber, therein housed various gas pulsation dampening means or gas pulsation containment means, at least one trap inlet port branching off from the compression chamber into the pulsation trap chamber and a trap outlet port communicating with the compressor discharge chamber after the discharge port.

Abstract: A gear wheel comprising a plurality of helical teeth, each helical tooth of the gear wheel having a tooth profile meshing with semi-encapsulation in a geared hydraulic apparatus. Each tooth having a profile which falls within a band of tolerance of +? 1/15 of the depth of a nominal tooth defined by a spline function interpolating a plurality of node points having pre-established coordinates {X,Y} with their origin on the gear wheel center.

Abstract: A piston for a pump includes a hub portion defining opposing outer surfaces and concave lateral portions between the opposing outer surfaces. The piston also includes inserts configured to provide a replaceable surface, the inserts being coupled to each of the opposing outer surfaces. A pump includes a housing having an inlet and an outlet, and at least two pistons having a hub portion and inserts. The pump may be a positive-displacement, rotary pump, and the pistons may be circumferential pistons.

Abstract: A piston for a pump a hub portion defining opposing outer portions, and inserts configured to provide an adjustable surface coupled to each of the opposing outer portions. The hub portion includes a first hub portion and a second hub portion configured to abut one another. Each of the inserts includes an outer shell and a base portion. The first hub portion includes a plurality of the opposing outer portions, and each of the base portions of the inserts is adjustably coupled to respective opposing outer portions of the first hub portion. A pump includes a housing having an inlet and an outlet, and at least two pistons having a hub portion and inserts. The pump may be a positive-displacement, rotary pump, and the pistons may be circumferential pistons.

Abstract: A rotor set comprises a pair of engaging rotors disposed in a pump room of a housing rotating oppositely with identical speeds. Each rotor comprises a plurality of lobes, and each lobe has a fan-shaped end with a curved edge. The lobe generates an eccentric force to the rotor during the rotation to reduce mechanical consuming energy and save dynamic energy. Therefore, the rotors can achieve strong eccentric torque and self-vacuum effect with low dynamic energy.

Abstract: Elliptical or oval shaped gears of a positive displacement gear pump are disclosed. The gears have specially designed teeth at the ends of the gears' major and minor diameter axes. For example the teeth at the ends regions of the major diameter axes include radially extending wipers or vanes that extend and run against the circular gear case bore walls to seal liquid slip paths at radial running clearance areas between the tips of the gear teeth and the case bores. The pump may also have moveable wearplates on one or both sides of the gears that may be loaded laterally to seal liquid slip paths at lateral running clearance areas between the side faces of the gears and the pump faceplate and backplate.

Abstract: An improved positive displacement pump provides improved wear characteristics. Specifically, rotor pads are provided on faces relative to an internal portion of the rotor housing as it relates to an end wall and a rear side of a cover plate. The rotor pads preferably have at least one of anti-galling and/or anti-friction or anti-wear characteristics thereby providing improvements over the prior art. A central member is preferably provided so that pad replacement may be relatively easily performed in the field in clean in place operations.

Abstract: A pair of Northey rotors for a vacuum pump, in which each rotor comprises two opposing, substantially parallel faces, and a peripheral surface located between the opposing faces. In order to reduce damage caused by pumping a gas stream containing liquid or solid particulates, a plurality of grooves is located on the peripheral surface for accommodating the particulates.

Abstract: An aircraft turbine engine Fuel Metering Unit (FMU) is provided including a main gear pump having a main drive gear and a main driven gear and a servo gear pump having a servo drive gear and a servo driven gear. The main drive gear and the servo drive gear are received on an input shaft. The main driven gear is mounted to a first shaft oriented parallel to and adjacent a first side of the input shaft. The main driven gear is in meshing engagement with the main drive gear. The servo drive gear is mounted to a second shaft arranged parallel to and adjacent a second, opposite side of the input shaft. The servo driven gear is in meshing engagement with the servo drive gear.

Abstract: A gear wheel comprising a plurality of helical teeth, each helical tooth of the gear wheel having a tooth profile meshing with semi-encapsulation in a geared hydraulic apparatus. Each tooth having a profile which falls within a band of tolerance of +? 1/15 of the depth of a nominal tooth defined by a spline function interpolating a plurality of node points having pre-established coordinates {X,Y} with their origin on the gear wheel center.

Abstract: The present invention deals with the analytical definition of a tooth profile for rotors used in gear pumps. The purpose is to obtain a pump characterized by noiseless operation, minimization of vibrations and pressure overoscillations generated in operating conditions at the beginning and end of life, and high specific displacement, in such a way to increase the delivery of the pump in given volume conditions. This profile is characterized by an active profile of the tooth flanks with involute stub-tooth with transverse contact ratio (?t) comprised in the range from 0.4 to 0.45, helical teeth with helical contact ratio (??) comprised in the range from 0.6 to 0.85, circular inactive tooth bottom and top profiles, with center (Of, Ot) and radius (rf, rt) defined by a non-dimensional parameter ? in the range from 1.1 to 1.6.

Abstract: A roots type fluid machine includes suction and discharge ports, rotary shafts and a pair of rotors. The rotor has a number n of lobe and valley portions with apex and bottom ends. The lobe portions are located on imaginary lines extending radially from an axis of the rotary shaft. The outer surface of each one of the rotors is generated by rotating an outline of the rotor including an arc and involute and envelope curves around and moving the outline in the direction of the axis. The arc has a radius R and a center located on the imaginary line. The involute curve is formed by an imaginary base circle having a radius r and a center located on the axis. The envelope curve is formed by an arc having a radius R. The number n is four or more. A torsional angle ? is over 360/n degrees.

Abstract: A pump.

Abstract: A multistage vacuum pump includes a stator housing a multistage rotor assembly, each stage having intermeshing Roots rotor components, wherein the tip radius of the rotor components at an inlet stage of the pump is larger than the tip radius of the rotor components at an exhaust stage of the pump, wherein a meshing clearance between the rotor components at the inlet stage of the pump is greater than a meshing clearance between the rotor components at the exhaust stage of the pump.

Abstract: A gear pump includes: a drive shaft; a first gear; a second gear; a first plate disposed between the first gear and the second gear, and arranged to liquid-tightly seal the first surfaces of the first and second gear; a pair of second plates disposed, respectively, on the second surfaces of the first and second gears, and arranged to liquid-tightly seal the second surfaces of the first and second gears, each of the second plates including a tooth top sealing portion having a seal surface arranged to seal a tooth top of the first gear and a tooth top of the second gear, and to form a suction portion with the first plate and the second plate; and an urging member arranged to urge the drive shaft toward the seal surface of the tooth top sealing portion of one of the first and second plates.

Abstract: The present invention relates to a rotor for a vacuum pump having a roots pumping mechanism, the rotor comprising at least two hollow lobes, each lobe having an outer wall which defines a lobe profile, a hollow cavity generally inward of the outer wall, and at least one strengthening rib located in the cavity to resist stress on the lobes generated during rotation.

Abstract: A Roots-type blower has first and second meshed, lobed rotors disposed in first and second chambers of a housing. Each lobe has first and second axially facing end surfaces defining a twist angle that is a function, at least partially, of the number of lobes on each rotor, and each lobe further defines a helix angle that is a function of the twist angle and an axial length between the first and second axially facing end surfaces of said lobe. The lobes cooperate with an adjacent surface of the housing to define at least one blowhole that defines a control volume, occurs in a cyclic manner, and moves linearly in a direction toward the outlet port. The blowhole provides communication between adjacent control volumes.

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 rotor is for use in a screw pump that pumps fluid by rotation of a pair of screw rotors engaged with each other in a rotor housing. The screw rotor includes a multiple-thread portion for pump suction side and a single-thread portion for pump discharge side. The screw rotor is formed so that the tooth profile of the multiple-thread portion is connected to the tooth profile of the single-thread portion through a boundary plane that is perpendicular to the rotation axis of the screw rotor. The first curved portion coincides with the third curved portion in the boundary plane.

Abstract: A supercharger is provided, comprising a plurality of rotatable supercharger rotors each having a plurality of interleavable lobes configured to move air from an inlet to an outlet of the supercharger. Inner chambers in the lobes define an end opening and perforated end faces, at the end openings defining at least one port, having a length and a diameter. The at least one port is configured to operate with an associated air mass in the inner chamber to attenuate sound adjacent to the end opening.

Abstract: A multistage vacuum pump has a pair of rotors disposed in each of pump chambers connected in stages. As the rotors rotate while intermeshing, a suctioned gas is compressed and discharged, angles of the rotors are adjusted so that a phase angle ?? of the rotors of adjacent pump chambers relative to a rotation angle C of the rotors during a single cycle of the pump chambers from intake to discharge and the number of stages S of the rotors satisfies ???C/S. When a rotor angle is ?1, an mth stage rotor angle is ?m, and an nth stage rotor angle is ?n in order from an upstream side of a gas flow direction, relationships of ?1<?m??n and ?1<?n, where n and m are natural numbers and n>m, are satisfied.

Abstract: A hydraulic device has an inlet side and an outlet side and includes two meshing cogwheels. Each cogwheel has external oblique teeth and is arranged between an inlet side and an outlet side. At least one control groove is provided on an end side of the cogwheels. The control groove periodically produces a pressure equalizing connection during the rotation of the cogwheels.

Abstract: A six-blade biaxial rotary positive-displacement pump includes a casing formed with a suction port and a discharge port, a pair of rotors accommodated in the casing and having rotor shafts rotatably mounted on housings fixed to opposed ends of the casing, respectively. Each rotor is formed with six blades extending radially equiangularly about the rotor shaft. Each blade is formed so as to have a constant thickness in a rotational direction of each rotor. Each blade has an apex and a valley, and a distance between the apex and the valley is set so as to range from three to five times larger than the thickness of each blade.

Abstract: There is a positive displacement flowmeter having a pair of rotors 11 rotatable on spaced apart parallel axis 14 within a housing 8 between inlet and outlet chambers 9, 10. The rotors have gear teeth 18 and are meshed together to rotate in accordance with volumetric fluid flow through the meter from the inlet chamber 9 to the outlet chamber 10. Each of the rotors has three lobes with rotor profiles between adjacent lobes being concave.

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: An external gear pump which has a certain flow rate or volumetric capacity at a given speed can be taken apart and the parts rearranged and assembled into a second pump operating at the same speed with a flow rate or volumetric capacity that is different from the original pump. No new parts are required for the second pump configuration and all original parts are used. With this structure, pumps with different flow rates can be built using fewer parts than conventional designs.

Abstract: A toothed wheel machine including a housing for receiving two meshing 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. Hydraulic mechanical forces are generated during the operation of the toothed wheel machine, an axial force component of the forces acting on each toothed wheel in the same axial direction. In order to counteract said axial force component, a pressure field is provided between at least one axial surface of one of the toothed wheels in the direction of the action of the axial force component, and the bearing body adjacent to the at least one axial surface.

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.

Abstract: A gear pump comprises a drive gear being mounted for rotation about a first axis and having a plurality of gear teeth at a radially outer location. A driven gear is mounted for rotation about a second axis, and having a plurality of teeth at a radially outer location. The drive gear teeth engage the driven gear teeth at a contact face to cause the driven gear to rotate. Slots are formed in the contact face of one of the drive and driven gear teeth.

Abstract: A pump comprises a driving rotor and a driven rotor that are positioned in a housing such that, as the driving rotor and the driven rotor rotate, the teeth of the driving rotor and the teeth of the driven rotor mesh to form a positive displacement seal. The teeth of the driving rotor and the driven rotor are configured such that seals between the inlet side and the discharge side of the pump are formed between only the leading surfaces of the teeth of the driving rotor and the trailing surfaces of the teeth of the driven rotor.

Abstract: A gear tooth including a concave base connected to its starting point at the root of the adjacent tooth and a top connected to the base via a first transition point. The top of the tooth includes two convex segments connected via a second transition point causing a curve break in the tooth profile.

Abstract: A gear pump comprises a first gear to be connected to a source of drive, and having a first plurality of gear teeth. A second gear has a second plurality of teeth engaged with the first gear teeth. The first gear teeth contact the second gear's teeth on a contact face, causing the second gear to rotate. The first plurality of teeth is greater than the second plurality of teeth.

Abstract: An improved positive displacement pump provides improved wear characteristics. Specifically, rotor pads are provided on faces relative to an internal portion of the rotor housing as it relates to an end wall and a rear side of a cover plate. The rotor pads preferably have at least one of anti-galling and/or anti-friction or anti-wear characteristics thereby providing improvements over the prior art. A central member is preferably provided so that pad replacement may be relatively easily performed in the field in clean in place operations.

Abstract: A shunt pulsation trap for a rotary lobe blower (pump) or vacuum pump reduces pulsation, NVH and improves efficiency without increasing overall size of the blower or pump. Generally, a rotary lobe blower (pump) or vacuum pump with the shunt pulsation trap has a pair of interconnected and synchronized parallel multi-lobe rotors housed in a transfer chamber with the same number of lobes for propelling flow from a suction port to a discharge port of the transfer chamber without internal compression. The shunt pulsation trap comprises an inner casing as an integral part of the transfer chamber, and an outer casing oversized surrounding the inner casing, therein housed various pulsation dampening means or pulsation energy recovery means or pulsation containment means, at least one injection port (trap inlet) branching off from the transfer chamber into the pulsation trap chamber and at least one feedback port (trap outlet) communicating with the blower outlet pressure.

Abstract: A bi-directional converter between pressure and rotational force includes engaging rotation members that continue to rotate while being adjacent to each other without collision; the rotation members and an outer wall form an enclosed space; rotation shafts of the rotation members are mutually engaged by gear wheels; the rotation members are synchronized and rotate in opposite directions; the rotation members are rotated by a volume change of the enclosed space by application of pressure from outside; and the volume of the enclosed space is changed by rotational force to generate a pressure difference. The bi-directional converter includes an open-close mechanism opening and closing supply exhaust paths inside the rotation member and disposed to the rotation shaft or the outer wall according to a rotation angle.

Abstract: The present invention deals with the analytical definition of a tooth profile for rotors used in gear pumps. The purpose is to obtain a pump characterised by noiseless operation, minimisation of vibrations and pressure overoscillations generated in operating conditions at the beginning and end of life, and high specific displacement, in such a way to increase the delivery of the pump in given volume conditions. This profile is characterised by an active profile of the tooth flanks with involute stub-tooth with transverse contact ratio (?t) comprised in the range from 0.4 to 0.45, helical teeth with helical contact ratio (??) comprised in the range from 0.6 to 0.85, circular inactive tooth bottom and top profiles, with centre (Of, Ot) and radius (rf, rt) defined by a non-dimensional parameter ? in the range from 1.1 to 1.6.

Abstract: A low noise gear set for use generally and preferably with a power plant having an engine driving a pump connected to a low pressure fluid source, generating high pressure fluid at an output. The idle gear meshes with the drive gear along two points of the profile of the corresponding gears. The first point being the root of one gear tooth meshing with the tip of the opposite gear tooth creating an initial first contact point and a subsequent second point along the profile when the teeth are disengaging at the first point and engaging at the second point, forming a sealed area, allowing the fluid to hydrostatically escape between the points.

Abstract: A rotor assembly is provided for a compressor assembly having a housing defining an inlet port, outlet port, and a rotor cavity in communication with the inlet port and outlet port. The rotor assembly includes a rotor body having a plurality of lobes formed thereon and rotatably mountable within the rotor cavity of the housing. The rotor body has a first end, substantially adjacent to the inlet port, and a second end, substantially adjacent to the outlet port, when mounted within the housing. Each of the plurality of lobes has an outer radius that is greater at the first end than at the second end.

Abstract: Device with rotary pistons that can be used as a compressor, a pump, a vacuum pump, a turbine, a motor and as other driving and driven hydraulic pneumatic machines, according to the invention, is used in several embodiments so as to enable its use with all hydraulic pneumatic machines and engines, by fitting constructional assemblies with gears and rotary pistons.

Abstract: A method of designing rotors for a Roots blower comprising a housing having cylindrical chambers, the housing defining an outlet port (19). The blower includes meshed, lobed rotors (37,39) disposed in the chambers, each rotor including a plurality N of lobes (47,49), each lobe having first (47a,49a) and second (47b,49b) axially facing end surfaces. Each lobe has its axially facing surfaces defining a twist angle (TA), and each lobe defines a helix angle (HA). The method of designing the rotor comprises determining a maximum ideal twist angle (TAM) for the lobe as a function of the number N of lobes on the rotor, and then determining a helix angle (HA) for each lobe as a function of the maximum ideal twist angle (TAM) and an axial length (L) between the end surfaces of the lobe. A rotor designed in accordance with this method is also provided.

Abstract: A method of controlling a gear pump comprising two meshing gear wheels (11, 12), wherein the two gear wheels (11, 12) are driven via respective shafts (2, 3) each by a drive unit (7, 8). A current position of the one gear wheel (11, 12) is determined with respect to the current position of the other gear wheel (12, 11), and the current position of the one gear wheel (11, 12) is continuously adjusted with respect to the current position of the other gear wheel (12, 11) according to specified predefined operating conditions.

Abstract: An arrangement including a gear pump (1), comprising a pump housing (10), two meshing gear wheels (11, 12) contained in the pump housing (10) and two shafts (2, 3) which are operatively connected to the gear wheels (11, 12) and extend through the pump housing (10), is disclosed wherein the two shafts (2, 3) are each operatively connected to respective drive units (7, 8). The arrangement includes a coupling unit (22) for compensation of eccentricities between the drive unit (7, 8) and the respective shaft (2, 3) is arranged between each gear wheel (11, 12) and drive unit (7, 8) and that a rotary encoder/sensor unit (24, 25) is arranged between the center of the gear wheel and the center of the respective drive.

Abstract: A roots type fluid machine includes suction and discharge ports, rotary shafts and a pair of rotors. The rotor has a number n of lobe and valley portions with apex and bottom ends. The lobe portions are located on imaginary lines extending radially from an axis of the rotary shaft. The outer surface of each one of the rotors is generated by rotating an outline of the rotor including an arc and involute and envelope curves around and moving the outline in the direction of the axis. The arc has a radius R and a center located on the imaginary line. The involute curve is formed by an imaginary base circle having a radius r and a center located on the axis. The envelope curve is formed by an arc having a radius R. The number n is four or more. A torsional angle ? is over 360/n degrees.

Abstract: There is disclosed a Roots type pump in which two rotors are rotated synchronously in a pump chamber to compress fluid therein, wherein respective stop positions of the rotors in the pump chamber at a time of stopping the pump are determined independently of each other.

Abstract: A gear pump comprises a drive gear being mounted for rotation about a first axis and having a plurality of gear teeth at a radially outer location. A driven gear is mounted for rotation about a second axis, and having a plurality of teeth at a radially outer location. The drive gear teeth engage the driven gear teeth at a contact face to cause the driven gear to rotate. Slots are formed in the contact face of one of the drive and driven gear teeth.

Abstract: Roots-type blowers with helical cycloidal rotors exhibit variation in leakback flow with angular position intrinsic to these rotor geometries. Calibration of individual blowers using a combination of high-resolution alignment and enhanced detection of residual noise phenomena permits noise in as-produced blowers to be significantly attenuated. Intrinsic lower limits of noise induced by leakback variation are associated with manufacturing tolerances, necessary clearances, and particular geometric considerations. Gross alignment errors (excluding contact between rotors) produce a characteristic noise pulse rate that is three times the shaft rate. Proper alignment suppresses this and reveals a pulse sequence at double this rate and at about half of the amplitude of faulty alignment. The novel process explains the error mechanisms and defines repeatable calibration methods for a mass-production environment, introducing appropriate gauges and methods for the task.

Abstract: An oil pump for an internal combustion engine includes a pump body with a first gear chamber and a second gear chamber, and a cover mounting to the pump body. The pump also has a check valve and a pressure relief valve in fluid communication with the gear chambers. The oil pump has a supply set of intermeshing involute spur gears in the first gear chamber with nine involute teeth. A return set of intermeshing involute spur gears with the same gear profile as the supply gears is housed in the second gear chamber. Both sets of gears are driven by a common drive shaft so that the pump may be retrofitted to existing engines. The profile of the gears provides for improved pump volume without increasing angular velocity or gear diameter over gears of the prior art. The return gears are deeper than the supply gears to provide an improved supply to return flow ratio.

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.