Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: A driving device includes a rotor unit including a rotation shaft, a fluid supplying portion, and a motor rotor, a housing that rotatably supports the rotation shaft, a stator case accommodating a motor stator and a motor rotor. The motor rotor includes a consequent pole rotor including a motor rotor core and a plurality of the magnets arranged along a circumferential direction of the motor rotor core. The magnets form a plurality of magnetic pole portions that serve as primary magnetic poles. The motor rotor core includes portions located between adjacent ones of the magnetic pole portions in the circumferential direction. The portions form magnetic-pole-forming portions that serve as secondary magnetic poles. The motor unit includes a magnetization inhibiting portion formed to inhibit magnetization of the fluid supplying portion. The support portion of the housing comprises a nonmagnetic metal.

Abstract: An air supply system is provided that uses two sets of rotors on a common set of shafts to boost air in two stages. The air supply system includes a housing and a first and a second rotatable shaft at least partially within the housing. A first and a second pair of rotors are included. Each pair of rotors has a first rotor supported for rotation on the first shaft and a second rotor supported for rotation on the second shaft. The housing has an inlet at the first pair of rotors, an outlet at the second pair of rotors, and an internal chamber between the first and the second pairs of rotors. Air flow from the inlet to the outlet thereby has a first pressure boost from the inlet to the internal chamber and a second pressure boost from the inlet chamber to the outlet.

Abstract: An electric oil pump apparatus for a hybrid vehicle, may include an electric motor having a motor rotor and a stator, wherein the motor rotor may be mounted on a rotary shaft, an oil pump having a pump rotor, wherein the pump rotor may be mounted on a rotary shaft, and a torsional damper installed on the rotary shaft of the motor rotor and a rotary shaft of the pump rotor between the motor rotor and the pump rotor.

Abstract: An electric pump includes: a second housing and a first housing separated from each other in an axial direction; a stator portion that accommodates an annular coil portion; an outer rotor portion that is rotated based on a magnetic field generated by the coil portion, at a position on the inner side of the housings; and an inner rotor that is rotatably supported by a support shaft portion having an axis that is offset from that of the outer rotor portion, and that has an outer peripheral surface that is engaged with an inner peripheral surface of the outer rotor portion. The second housing is fitted onto the support shaft portion, to which the first housing has been fixed, from one side of the support shaft portion in the axial direction. As a result, the outer rotor portion and the stator portion are clamped between the first housing and the second housing from both sides in the axial direction.

Abstract: A rotary machine includes a rotary shaft having two driving reactive force receiving parts that are displaced in an axial direction and are applied with diametrical reactive forces having different rotation phases from driving targets as normal loads; and bearings that rotatably support the rotary shaft wherein the rotary shaft is rotated at a state where the rotary shaft is supported by the bearings to drive the driving targets via the driving reactive force receiving parts, wherein the bearings are respectively provided at both axial sides of one of the two driving reactive force receiving parts, which receives a higher normal load, and wherein a leading end side of the rotary shaft more than the other of the two driving reactive force receiving part, which receive a lower normal load lower than the higher normal load, is configured as a free end.

Abstract: A pump unit for a urea-SCR system may use a fuel pump of a vehicle engine and may have a case portion surrounding a motor portion and a pump portion. The motor portion may include a barrier wall surrounding a rotator so as to separate the rotator from a stator of the motor portion, and the pump portion includes a shield in which a suction hole and a supply hole for fluid are formed and that is disposed between the pump portion and the motor portion so as to prevent fluid from leaking into the motor portion, so the motor is protected from the urea solution to prevent corrosion thereof, manufacturing cost is reduced, and noise caused by the vibration is reduced.

Abstract: One embodiment of the pump system includes a cover housing and a main body affixed to one another for operation. A drive and idler gear may be mounted within a gear chamber in the main body for rotation there about, and inlet fluid may be provided on both the axial and radial surfaces of the drive and idler gear. The cover housing may be outfitted with one pressure relief channel or with two pressure relief channels of different geometric sizes and with different actuation pressures. The drive and/or idler gear may have dimples fashioned on an axial surface thereof, and lubricant troughs may be fashioned at various locations in the main body and/or the cover housing to reduce wear within the pump.

Abstract: A progressing cavity pump comprises at least an inner pump rotor enclosed by at least an outer pump rotor so as to collectively form one or more, in principle, separate pump cavities which, according to known geometric principles, will be moved axially through the pump upon bringing the rotors into coordinated rotation. At least two pump sections are disposed therein, each of which comprises one outer pump rotor and one adapted inner pump rotor. The outer pump rotors of all pump sections are fixedly supported and arranged along the same axis, wherein all the inner rotors are supported in fixed positions relative to a pump casing of the pump. The outer rotors of all pump sections are driven by the same motor via at least one differential arranged to allow each pump section to rotate at a mutually different rotational speed.

Abstract: A pump body is formed of a pump housing and a pump plate provided in front of the pump housing. A motor housing is fixed to a rear end of the pump housing, and accommodates a pump driving electric motor. A bearing device that supports a motor shaft includes a first bearing that is arranged in a closed-end hole formed in a rear face of the pump plate and supporting a front end portion of the motor shaft, and a second bearing that is arranged radially inward of a cylindrical bearing support portion formed in the pump housing and extending inside the motor housing and that supports a middle portion of the motor shaft. A pump rotor is arranged between the first bearing and the second bearing.

Abstract: A gerotor pump includes an inner ring and an outer ring. The inner ring is rotateable about an axis, where the inner ring has an outer diameter contact surface. The outer ring has an inner diameter contact surface that defines a central opening. The central opening receives the inner ring, and a portion of the inner diameter contact surface engages a portion of the outer diameter contact surface of the inner ring. A motor including a rotor and a stator that surrounds the rotor is included. The rotor surrounds the outer ring and exerts a driving force on the outer ring such that the outer ring rotates about the inner ring. The inner diameter contact surface of the outer ring and the outer diameter contact surface of the inner ring create a plurality of chambers. Rotation between the inner ring and the outer ring expand and contract the chambers to expel fluid from the gerotor pump.

Abstract: An electrically driven rotary piston machine which operates as a rotary piston pump or rotary piston compressor wherein the rotary piston machine has a basic housing, which holds an electrical coil and pump head, wherein the pump working space is preferably bounded by a trochoid toothing of the rotors. The pump head which can usually be manufactured relatively economically is embodied as a disposable part and therefore has a quick-action connection with the more complex basic housing.

Abstract: An apparatus includes a housing defining a first cavity containing a pump, a second cavity containing a filter and a lumen configured to provide fluid communication between the first cavity and the second cavity. The housing has a first end portion configured to be disposed within a fluid reservoir and a second end portion including a flange configured to be disposed outside of and coupled to the fluid reservoir. A surface of the first end portion defines a first opening in fluid communication with the first cavity. A surface of the second end portion defines a second opening in fluid communication with the second cavity. A cover is configured to be removably coupled to the second end portion of the housing about the second opening such that the filter can be removed from the second cavity when the flange is coupled to the fluid reservoir.

Abstract: A gear pump capable of alternately distributing a fluid in two distinct utilization circuits without the need for a switch. The gear pump (1) comprises two fluid outlet ports (5, 6) connected to two fluid utilization circuits and linked to the discharge chamber (C) of the pump via an integrated commutation (7). These commutation (7) comprise two distribution circuits (50, 60), located in a fixed support plate (70), and two buffer channels (30, 40), located in the rotary toothed wheels (3), arranged so as to alternately open and close the distribution circuits according to a commutation cycle that approximately corresponds to the rotation of the toothed wheels over half a revolution.

Abstract: A toothed wheel (16) is provided with teeth, in which a cross section of a respective first section (24) of the tooth (23) has an outer contour that projects in at least one partial area of the outer contour relative to an outer contour of the adjoining second section (26) of the tooth (23), and is elastically designed and/or mounted, as well as a pump unit, in particular as a metering pump unit, with a drive having a toothed gearing with the toothed wheel.

Abstract: A liquid gear pump includes a gear pump assembly and an electric motor with an motor shaft. The gear pump assembly includes a pump housing which defines a pump chamber, an inlet and an outlet which are in fluid communication with the pump chamber, and a driving gear and an idle gear which are received in the pump chamber. The driving gear is driven by the motor shaft. The idle gear is supported on an idle shaft and engaged with the driving gear. The driving gear and the idle gear are made of a material with a main component of PPS.

Abstract: In a method of operating a compressor at startup, the compressor is rotated in reverse for a brief period of time. The compressor is of a type that does not compress liquid when rotated in reverse. The purpose is to boil off the liquid refrigerant from the oil by heating and agitating the mixture of oil and refrigerant in the oil sump. This results in a much more benign forward start as less refrigerant is drawn into the compressor pump and the amount of oil pumped out of the compressor on start up is minimized. Also, the viscosity of oil is increased and lubrication of the bearings is improved. After a short period of time reverse rotation is stopped and the compressor can start rotating in the forward direction. The short period of time of reverse rotation is varied based upon system conditions. In one embodiment, the variation can occur by reducing the reverse run time as ambient temperature increases.

Abstract: The present invention relates to a dry vacuum pump unit capable of achieving ultimate pressure of about 1 Pa. The vacuum pump unit includes a main pump (15) disposed at an outside-pressure side, and a booster pump (16) disposed at a vacuum side. The booster pump (16) and the main pump (15) are coupled in series. The booster pump (16) has a higher pumping speed than that of the main pump (15). Each of the main pump (15) and the booster pump (16) includes a pair of pump rotors (52a and 52b), a casing (50) having an inlet port and an outlet port, and a pair of magnet rotors (54 and 54) rotatable with the pair of pump rotors.

Abstract: A pumping unit having a pump chamber with a rotor mounted in a rotatable manner within the chamber. The pumping chamber is formed by a circumferential wall and two end walls. The circumferential wall is formed on an annular collar of a pump part and has on its inner surface a track on which sealing bodies of a rotor roll. To avoid deformation of the pump part by hydraulic forces or by pressing-in forces, ribs are arranged on the outer surface of the circumferential wall which extend away from the pump chamber. A shoulder is arranged on the side of the end wall which is directed away from the pump chamber. The shoulder is connected by a press fit to the pump housing and has thin walls so that pressing forces do not result in any deformation to the end wall of the pump chamber.

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 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: In an engine driven unit of a feed pump, the feed pump is accommodated in a hollow space which is enclosed radially by a rotating functional wheel of a component of the motor vehicle formed, for example, by a pulley wheel, which may be driven directly by the crankshaft of the internal combustion engine.

Abstract: A screw compressor includes a casing and a compression mechanism accommodated in the casing. The compression mechanism has a screw rotor, a gate rotor and a communication mechanism. The sate rotor has a flat plate shape. A rotational axis of gate rotor is orthogonal to a rotational axis of the screw rotor. The communication mechanism is arranged to communicate a high pressure space and a low pressure space in the casing.

Abstract: The invention relates to a gear pump (1) for conveying a fluid, said gear pump comprising a rotatably mounted, external geared toothed wheel (3) and an internal geared annular gear (2) that are meshed in order to generate a conveying action, and are arranged together with an electrically commutable stator (7) in a housing (5). The stator (7) extends concentrically around the annular gear (2) and interacts with the annular gear to generate an electromotive force. The annular gear (2) has a closed, homogeneous cylindrical surface and a plain bearing (13) is provided on the stator (7).

Abstract: An electric pump unit that may be compactified and that may be reduced in weight and cost is provided. An electric pump unit is configured such that a pump chamber having an oil suction port and an oil discharge port is formed on an inner side of a motor stator that is fixedly provided on an inner periphery of a synthetic resin unit housing and only part of an inner peripheral side of which is exposed to an inside of the unit housing, a pump outer rotor is arranged on an inner side of the motor stator in the pump chamber so as to be able to rotate using an inner periphery of the motor stator as a guide, a pump inner rotor that is supported for rotation by the unit housing is arranged on an inner side of the pump outer rotor, and a motor rotor is formed such that a permanent magnet is held by a synthetic resin permanent magnet holding portion that is provided by integral molding on an outer periphery of the pump outer rotor.

Abstract: This invention relates to a gear pump (1) for delivering a fluid, comprising an externally toothed gearwheel (3) rotatably mounted on a journal (4), and an internally toothed annular gear (2), said gearwheel and gear meshing so as to produce a delivery action, and arranged together with an electrically commutatable stator (7) inside a housing (5). The stator (7) extends concentrically around the annular gear (2) and cooperates with a magnetic ring (6) in order to generate an electromotive force and the magnetic ring (6) together with the annular gear (2) rotate in order to produce the delivery action. The annular gear (2) is mounted by means of a sliding bearing (25).

Abstract: Various methods are disclosed for manufacturing pump-heads having a housing enclosing at least one rotary member. In an exemplary method first and second housing portions are provided that collectively, when assembled, define a pump-cavity that accommodates the rotary member(s). The rotary member(s) is assembled into the pump-cavity, along with at least one soluble spacer of a defined thickness that corresponds to a desired clearance of the rotary member relative to the pump-cavity. The spacer contacts a surface of the rotary member facing a corresponding surface of the housing portion. The first and second housing portions are attached together to form the pump-cavity containing the rotary member(s). The soluble spacer is dissolved to provide the desired clearance of the rotary member in the pump-cavity. As the housing portions are attached together, e.g., by adhesive bonding, the spacer establishes the desired clearance of the rotary member(s) in the pump-cavity.

Abstract: A pump, reduction gear, motor combination wherein the reduction gear and pump have nesting shafts internal to at least one of the housings of the pump and reduction gears. The housings meet at cooperating front and rear flanges having a plurality of bores therethrough, and selection from a number of orientations is possible whereby a pump outlet can be selectively oriented at a number of predetermined orientations relative to the reduction gears. The reduction gears also preferably provide a base spaced from the front flange which provides for mounting to a support to thereby suspend the motor cantileveredly from the reduction gears.

Abstract: A progressing cavity pump/motor includes a stator tube (12), a rotor (20) within the stator tube, and a coupling assembly (30) interconnecting the upper and lower rotor sections. The coupling includes a drive adapter (32) and a socket adapter (36) for transmitting torque between the upper and lower rotor sections, and at least one alignment surface (60) in cooperation with a mating surface to rotationally position the drive adapter within the socket adapter at a selected circumferential position. The pump/motor may be reliably assembled in the field while maintaining precise axial and rotational positioning of the rotor sections.

Abstract: An air compressor assembly includes a compressor housing, an intake port defined by the compressor housing for intake of the air, and a plurality of guide contours disposed adjacent to the intake port. The guide contours include between three and six strips. A valve unit is disposed adjacent to the intake port, the valve unit comprising a closing element that assumes an opened position during operation and a closed position when in a switched-off state. The closing element is plate-shaped, is axially movable, and is guided by the plurality of guide contours between the opened position and the closed position. A stroke limitation element is provided to limit axial movement of the closing element in the opened position. A spring is disposed between the closing element and the stroke limitation element. The spring provides a return force to the closing element to bias the closing element into the closed position.

Abstract: The invention relates to a rotor pump having an internally toothed outer ring and an externally toothed inner ring which is mounted therein and intermeshes therewith, wherein the outer ring and the inner ring are arranged axis-parallel to one another, and the axes of the outer ring and of the inner ring are at a distance from one another, and the outer ring is connected to a hollow shaft motor with a stator which is fitted with windings, and to a rotor which is rotatably mounted therein, characterized in that the outer ring forms the rotor of the hollow shaft motor.

Abstract: A method of inhibiting combustion within a vacuum pump is provided. The method steps include monitoring and composition of a fluid within the pump and supplying purge gas to the pump to inhibit the onset of a combustion of the fluid. There is also provided a pumping arrangement comprising a vacuum pump (1) together with means (8) for supplying purge gas to the pump. Sensor means (21a, 21b, 21c) are provided for outputting a signal indicative of the onset of a combustion condition within the pump. Control means (22) receive the signal and, in turn, actuate the supply means (9) dependant on the signal received.

Abstract: A rotary pump intended to pump a fluid in a system on board a vehicle, such pump comprising a stator, a rotation axle attached both to a mechanical pumping element and a magnetic rotor, and electrical connections. The rotor, the stator and the electrical connections are overmolded in a leaktight manner with a plastic.

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

Abstract: A sleeve supporting structure for an automatic transmission, including a sleeve member disposed on a radial outside of an input shaft, a rotational shaft portion disposed in a motor, an oil pump housing, and a stationary member supporting an outer circumferential surface of the rotational shaft portion and including a projection that projects toward a side of the oil pump. The sleeve member has one axial end portion overlapped with the rotational shaft portion in the radial direction thereof and an opposite axial end portion meshing with an inner gear of the oil pump, and is supported by an inner circumferential surface of the oil pump housing and an inner circumferential surface of the rotational shaft portion. The projection of the stationary member is fitted onto an outer circumferential surface of the oil pump housing so as to form a faucet joint in cooperation therewith.

Abstract: A fluid pump having a pump housing that includes at least one expansion joint, provides volume compensation, as needed, to adjust for changes in pressure in the pump housing. Various embodiments automatically and passively reduce static pressure in the pump housing associated with a freezing event, thereby preventing damage to the pump head. Volume compensation is achieved by employing, in each expansion joint, a dynamic seal that allows relative movement of two portions of the pump housing, and a bias that provides a selected counter-force to the movement of the housing portions. The subject pumps are particularly suited for use in automotive and other rugged applications, in which fluid pumps may experience recurring freezing events.

Abstract: According to an aspect of the present invention, an electric pump includes: a housing; an outer rotor; an inner rotor; a base member facing one side surface of the outer rotor and one side surface of the inner rotor; a side plate member, having a facing surface facing the other side surface of the outer rotor and the other side surface of the inner rotor and a non-facing surface opposed to the facing surface; a shaft; a suction port; a discharge port; a negative pressure applied region; a positive pressure applied region; and a relief valve, discharging the fluid from the positive pressure applied region to a non-facing surface side of the side plate member when a pressure applied at the positive pressure applied region exceeds a predetermined value.

Abstract: To maintain the functionality as a compact and inexpensive motor-mounted internal gear pump and also offer further inexpensiveness and reliability. The motor-mounted internal gear pump 80 has a pump part 81 including: an inner rotor 1, an outer rotor 2, a pump casing and an internal shaft 5. The pump casing has flat inner surfaces facing both end faces of the inner rotor 1 and the outer rotor 2. The internal shaft 5 includes a bearing 51 which is inserted into an axial hole of the inner rotor 1 and a fitting part 53 extending from both its ends in both axial directions. The pump casing includes two pump casing members 3, 4 as separate members with flat inner surfaces 25, 26 respectively.

Abstract: A gerotor pump includes an inner ring and an outer ring. The inner ring is rotateable about an axis, where the inner ring has an outer diameter contact surface. The outer ring has an inner diameter contact surface that defines a central opening. The central opening receives the inner ring, and a portion of the inner diameter contact surface engages a portion of the outer diameter contact surface of the inner ring. A motor including a rotor and a stator that surrounds the rotor is included. The rotor surrounds the outer ring and exerts a driving force on the outer ring such that the outer ring rotates about the inner ring. The inner diameter contact surface of the outer ring and the outer diameter contact surface of the inner ring create a plurality of chambers. Rotation between the inner ring and the outer ring expand and contract the chambers to expel fluid from the gerotor pump.

Abstract: A power transmission apparatus includes a drive roller and a driven roller made of magnetic material, which are rotatable about different axes, and which are provided with a gap therebetween, a case enclosing the rollers, an input shaft and an output shaft connected coaxially with the rollers through the case, respectively, and a magnetic fluid housed in the case to fill the gap. The apparatus includes an electromagnetic coil for generating magnetism, and a magnetic path of the magnetism generated by the electromagnetic coil is formed so that a magnetic field is generated from the drive roller or the driven roller toward the driven roller or the drive roller via the gap.

Abstract: A compressor includes a housing and one or more working elements. A muffler is located downstream of the discharge plenum and a helmholtz resonator is located in the discharge plenum upstream of the muffler.

Abstract: An oilless screw compressor incorporating water-cooled cooling units for cooling compressed air discharged from compressor bodies having a pair of male and female screw rotors which can be rotated in a contactless and oilless manner, the cooling units comprising a plate type heat-exchanger, and the amount of cooling water for the plate type heat-exchanger being adjustable. With this configuration, a difference between a temperature during load operation and a temperature upon automatic stopping and during unload operation of the compressor can be reduced, so that the cooling unit can be restrained from being damaged or broken within a short period, thereby it is possible to provide a highly reliable oilless screw compressor.

Abstract: An electric pump includes a stator, a rotor, a shaft, a bearing part, and a pump unit. The stator has a magnetic part, and the stator forms a rotation magnetic field when a coil of the stator is energized. The bearing part has a longitudinal central position that is positioned on an imaginary plane perpendicular to a rotation axis of the rotor. The imaginary plane is positioned within an inner range defined between longitudinal end portions of the magnetic part of the stator.

Abstract: An electrical driven pump unit having two hydraulic pumps and two electric motors that are fitted in such a way as to make it possible to obtain the unit's power by adding together the power of the two motors.

Abstract: A method of running a down hole rotary pump using a top drive, sucker rod or any drive shaft from surface. A first step involves providing a gear box having an input end and an output end. The gear box is being capable of receiving an input of a first speed at the input end and producing an output of a second speed which is one of either faster or slower than of the first speed at the output end. A second step involves positioning the gear box down hole with the input end coupled to a remote lower end of a sucker rod and the output end coupled to a rotary activated pump. A third step involves applying a driving force to the sucker rod to rotate the sucker rod at the first speed, with the rotational force being transmitted to the rotary activated pump through the gear box which rotates the rotary activated pump at the second speed.

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: An externally mounted electric fluid pump for pumping fluid within a power transmission device is disclosed. The pump includes a housing adapted to be mounted to an external surface of the power transmission device. The pump is positioned within the housing and includes an input member. An electric motor is positioned within the housing and drives the input member. A controller is positioned within the housing to control the electric motor and vary the output of the pump.

Abstract: An electrostatic spraying device has a capability of confirming that the device is ready for making an electrostatic spraying of the liquid composition on a user's skin. The device includes a nozzle and a pump for dispensing the liquid composition out through the nozzle. An emitter electrode is disposed to electrostatically charge the liquid composition being dispensed for making the electrostatic spraying. The device is provided with a power switch and a selector for selection between a spraying mode and a dripping mode. In the dripping mode, the pump is alone actuated to dispense the liquid composition absent electrostatic charge. In the spraying mode, both of the pump and the emitter electrode are activated to make the electrostatic spraying. Thus, the user can be easy to drip the liquid composition by simply manipulating the selector prior to initiating the electrostatic spraying.

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 submersible electric pump includes a housing adapted to be submerged within a fluid to be pumped having apertures extending therethrough. An electric motor stator is positioned within the housing in communication with the apertures and is adapted to be in contact with the fluid. Inner and outer pump rotors are positioned within the housing in meshed engagement with one another to pump fluid when rotated. A plurality of permanent magnets are fixed for rotation with the outer rotor.