Abstract: A backup hydraulic pump supplies pressure oil to an actuator when a loss or degradation of the function of an aircraft central hydraulic power source occurs. A control valve controls the operation of the actuator by controlling supply and discharge of the pressure oil to/from the actuator. The control valve has a main body provided with a pressure oil port, a spool portion that moves in a sliding manner within the main portion and switches a path of the pressure oil, and a drive portion. The drive portion is connected to an end of the spool portion and drives the spool portion by electromagnetic force so as to control the position of the spool portion based on an electric signal.

Abstract: A stator member may comprise a core member comprising a plurality of cores disposed juxtaposed to one another, a coil being wound around each of the cores and a terminal member attached to one end of the core member. The terminal member may comprise a terminal portion comprising three external terminal portions used as terminals of U, V, and W phase and a common terminal portion used as a common terminal. The three external terminal portions and the common terminal may be integrally provided. A plurality of fitting portions may protrude from the terminal portion toward the core member. Each of the plurality of fitting portions may be configured to be fitted into a corresponding one of a plurality of recessed portions formed at the one end of the core member in an elastic deformed state.

Abstract: According to one embodiment, a motor stator includes a substantially cylindrical stator iron core and insulators. The stator iron core includes a yoke, teeth, and U-shaped grooves. The U-shaped grooves are formed on the circumference of the yoke in the axial direction. The insulators each include an outer circumference wall, hoisting drums, inner guards, and at least three engagement claws. The engagement claws are located spaced apart in the circumferential direction on the outside of the outer circumference wall and fitted in axial-direction ends of the U-shaped grooves, respectively. One of the engagement claws is arranged such that a first circumferential-direction side portion of the engagement claw is in contact with a first side wall of one U-shaped groove. Another is arranged such that a second circumferential-direction side portion of the engagement claw is in contact with a second side wall of another U-shaped groove.

Abstract: A vacuum pump having a vacuum pumping mechanism mounted for rotation by a shaft and a brushless motor for rotating the shaft where the vacuum pumping mechanism comprises a turbo pumping mechanism comprising pumping stages, and a molecular drag pumping mechanism comprising at least one pumping stage, and a shaft supported for rotation by bearings, and where the motor comprises a permanent magnet rotor fixed relative to the shaft and the rotor has four poles and a stator has non-overlapping stator coils.

Abstract: A hydraulic control system for preventing shortage of lubricant and coolant during charging of an accumulator is disclosed. The hydraulic control system is comprised of: a hydraulic pump; an accumulator for storing fluid from the pump; and a constant delivery site which is connected to the pump in parallel with the accumulator, and which requires hydraulic fluid constantly during activation of the hydraulic pump. A pressure level of the fluid discharged from the pump is regulated to a level possible to be delivered to the accumulator, and the fluid resulting from the pressure regulation is delivered to the constant delivery site. Meanwhile, a pressure higher than that required by the constant delivery site is stored in the accumulator. The hydraulic control system is characterized by a fluid increasing means that delivers additional fluid to the constant delivery site together with the fluid resulting from said pressure regulation, when delivering the fluid discharged from the pump to the accumulator.

Abstract: A device for blowing air by a narrow slit nozzle assembly is provided. The device includes a base seat for generating an air stream to supply air flow and a narrow slit nozzle assembly supported by the base seat for blowing air. An airflow passage is connected between the base seat and the nozzle assembly. An intake end of the airflow passage is opened on the outer surface of the base seat, and an output end is connected to the nozzle assembly by a pivot component. An intake end of the nozzle assembly is connected to an output end of the base seat by the pivot component. An impeller and an electric motor for driving the impeller to rotate are provided within the base seat. The nozzle assembly is rotatably fixed on the base seat by the pivot component. The rotation direction of the nozzle can be adjusted by the rotation of the pivot component around the airflow passage. And when the fan is idle, the nozzle can be folded so as to save space.

Abstract: A motor-driven compressor includes a compression unit, an electric motor, a housing that includes an accommodating chamber and a wiring connection port, a motor driving circuit that includes a substrate arranged in the accommodating chamber, wiring electrically connected to the substrate and extending out of the housing through the wiring connection port, and a resin sealing member fitted to the wiring connection port. The wiring includes a primary conductor, which has a first end connected to the substrate and a second end, and a secondary conductor, which is connected to the second end of the primary conductor and arranged outside the housing. The secondary conductor includes a wire portion and a sheath that is made of an insulating material and covers the wire portion. The sealing member covers the sheath and a junction between the primary conductor and the secondary conductor.

Abstract: An electric compressor is disclosed in which gas in a motor housing of a rotating electric machine is drawn into a compression chamber and then discharged by the rotating electric machine. The rotating electric machine includes a stator, teeth, coils of different phases, and phase-to-phase insulation sheets provided between coils of different phases. An inlet port is provided in the motor housing. The inlet port draws gas from the outside of the motor housing. An inflow direction of the gas flowing through the inlet port intersects a coil end of one of the coils. A part of the phase-to-phase insulation sheet faces the inlet port and covers an intersection surface of the coil end that intersects the inflow direction.

Abstract: A motor-driven compressor includes a housing made of a metal material, a compression portion, an electric motor, and a cover. The compression portion and the electric motor are accommodated in the housing, and the cover is attached to the housing. The cover is formed by a plastic portion and a shield made of a metal material that intercepts electromagnetic noise. A motor drive circuit for driving the electric motor is accommodated in an accommodation space defined by the housing and the cover. An elastic sealing member is located between the housing and the cover. The shield includes an extended portion that extends toward the housing and is arranged inside the sealing member. The extended portion is in contact with the housing.

Abstract: TECHNICAL PROBLEM To provides a blower which aims at both a noise reduction effect and the inherent blowing performance SOLUTION TO PROGRAM An axial flow blower which is provided with an electric motor, and a blower fan which has a hub which is attached to said electric motor and a plurality of blades which are provided at said hub in a radial manner, wherein in said axial flow blower, a negative pressure surface of a leading edge of each said blade, comprised of a negative pressure surface and a positive pressure surface, is provided with a plurality of triangle shape projections which have vertexes along the leading edge, and the positive pressure surface of the leading edge of each said blade is not provided with said triangle shape projections but is a smooth continuous surface.

Abstract: A fluid pumping system for an engine includes a pump; a summing differential connected to the pump; a gearbox connected to the summing differential, wherein the gearbox causes the pump to rotate to provide a fluid flow in the engine via the summing differential; and a motor connected to the summing differential, wherein the motor adjusts a rotational speed of the pump via the summing differential

Abstract: An oil pump in a motor vehicle, having a case and an electric motor mounted in the case. The electric motor drives a pump stage which is likewise mounted in the case. The oil pump is an axial flow centrifugal pump.

Abstract: A vibration fan includes a base, an electromagnetic actuator and a blade. The electromagnetic actuator is disposed on the base, and includes a movable magnetic component and a fixed magnetic component. The movable magnetic component reciprocates relative to the fixed magnetic component. The blade is connected to the movable magnetic component.

Abstract: An electrical submersible pumping system (ESP) having a stator lamination stack that is anchored to prevent the stack from spinning. The ESP includes a motor section having a housing with an axial bore. A groove circumscribes an inner surface of the housing and a snap ring is set in the groove. A portion of the snap ring projects into the bore and exerts an axial compression force onto the lamination stack The snap ring includes a gap that aligns with a bead of material that is set in the groove; engagement between the bead and gap prevents the snap ring from spinning in the groove. The bead, that in an embodiment is a weld, can extend across all or a portion of the groove and can also provide coupling between the lamination stack and the housing.

Abstract: The invention relates to a pump turbine system, comprising a turbine with a turbine impeller as well as a turbine spiral housing and a turbine suction pipe; a pump with a pump impeller as well as a pump spiral housing and a pump suction pipe; the two spiral housings are arranged to run in opposite directions; a shaft on which the turbine impeller and the pump impeller are non-rotatably arranged; an electrical machine that is in drive communication with the shaft or can be brought into such communication; the pressure lines of the two spiral housings open into a common pressure line; both suction pipes are each connected to suction lines, with both suction lines opening into a common suction line; with a separate shut-off element each being arranged in the suction lines.

Abstract: An electric fluid pump having a rotor. The rotor of the pump is provided with elements that produce an at least partially axially directed fluid flow in the wet section of the pump during rotation of the rotor. This fluid flow serves to cool components of the pump that are arranged in or on the wet section.

Abstract: Provided is an electro-hydraulic drive system including first and second electro-hydraulic transmissions for driving respective wheels, the transmissions each including an electric motor, a hydraulic pump driven by the electric motor, and a hydraulic motor drive by the hydraulic pump. When used in a turf vehicle, such as a zero-turn-radius mower, the electro-hydraulic drive system operates the wheels independently from an engine of the mower, thereby allowing the mower to be moved without having to start the engine. In this way, power consumption is lowered and total efficiency of the mower is increased.

Abstract: The present pump devices provide a dual pump using two (or more) electric motors (e.g. brushless DC motors) driving the pumps independently, including integration of hydraulic and electrical components and connectors. The illustrated arrangements include an in-line single shaft version, a parallel separate shaft version, and an inside-outside version. Each configuration includes a housing supporting formation of: shared structural support for the pumps and motors (e.g., bearings, stator, relationship of components), fluid pump and hydraulic system (e.g., fluid passageways, ports connectors) and motor electrical control (e.g., control circuitry and sensory components).

Abstract: A fluid dispenser includes a container configured to store a fluid, a pump for placement in an interior of the container and for pumping contents of the container to an exterior of the container, a motor system for driving the pump and including a rotor for placement in the interior of the container, and a stator for placement on the exterior of the container, wherein an electric current is passed through the stator for causing rotation of the rotor.

Abstract: An on board inert gas generation system receives cabin air, or air from another relatively low pressure source, passing a portion thereof through an energy recovery turbine to ambient to extract power which is used to provide all, or part of the energy required to drive a positive displacement compressor to co press another portion of cabin air to increase the pressure thereof to be suitable for supply to an air separation module.

Abstract: A pumping set includes an electric drive motor, which exhibits a stator casing and at least one terminal box connected with the latter, wherein the interior of the terminal box exhibits at least one separating wall, which divides an interior space of the terminal box into at least one electronics area with electronic components and a connection area, wherein the connection area incorporates both electrical connections for at least one connection line along with contacts for establishing an electrical connection with electrical or electronic components arranged inside the stator casing.

Abstract: A motor control device includes an electric power conversion circuit, an electric current detection unit, a load fluctuation detection unit, and an adjustment unit. The conversion circuit supplies AC power to a motor configured to drive a mechanism unit by converting DC power into AC power. The current detection unit detects the electric current flowing through the conversion circuit or the motor. The load fluctuation detection unit detects the periodic fluctuation of the load of the motor, based on the electric current. The adjustment unit adjusts a phase of the AC voltage of the AC power, by controlling the conversion circuit based on the fluctuation. The phase of the AC voltage has a first component that increases with respect to a magnetic pole position of the motor, and a second component that changes in synchronization with the fluctuation.

Abstract: A compressor having a simplified structure includes a rotation shaft having a spiral groove formed in an outer circumferential surface of the rotation shaft, and a cap member that accommodates a lower portion of the rotation shaft so that the rotation shaft can rotate in the cap member. The cap member may be fixed to one of a stator and a frame such that the cap member does not rotate together with the rotation shaft. Through the simplified structure, oil stored in a sealing case can ascend, and noise caused by rotation of the rotation shaft can be reduced.

Abstract: A drive device for a fan module comprises an electric motor, a housing and a vibration damper for fastening the electric motor to the housing in a manner which damps vibrations. The electric motor has a radial engagement element for engaging into the vibration damper, and the housing has a radial recess for receiving the vibration damper. Here, the vibration damper frames the engagement element in the radial direction thereof.

Abstract: This electric fan has a rotation shaft that is provided rotatably with respect to a stator, a rotor yoke provided on the rotation shaft and formed in a bottomed cylindrical shape so as to cover the stator from a front surface, and a bracket that fixes the stator to a fan shroud and is formed so as to cover a rear surface of the stator, with a fan body provided so as to integrally rotate with the rotation shaft and the rotor yoke. The fan body has a fan boss formed in a bottomed cylindrical shape so as to cover the rotor yoke from a front surface, and a plurality of blades that is provided protruding radially from an outer circumferential surface of the fan boss. A first labyrinth portion is provided between an opening portion of the fan boss and the fan shroud.

Abstract: Systems and methods including a motor or electromagnets to control the movement of one or more pistons in a pumping chamber. The pumping chamber may include a pump inlet and a pump outlet in fluid communication with the pumping chamber. Surfaces on a piston or pumping chamber may include hydrodynamic bearing surfaces.

Abstract: A medium voltage drive for driving a motor of an electric submersible pump can include inverter circuitry that includes an output for output of power and a load filter connected to the output that includes inductors and capacitors that include inductance (L) and capacitance (C) values that determine a resonance frequency (fr) value within a range from approximately 750 Hz to approximately 1000 Hz according to the equation fr=(2?(LC)0.5)?1. Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: An ESP is suspended downhole on a cable comprising spirally wound copper clad steel conductors surrounded by nonmetallic sheathing wound in an opposite spiral direction, preferably in the direction of rotation of the rotor of the ESP. The torque exerted on the cable by the ESP is reacted against the conductors, relieving stress from the sheathing so that the cable may be light in weight yet support substantial loads.

Abstract: An electric compressor includes: an electric motor; a compression mechanism driven by the electric motor; a housing accommodating the electric motor and the compression mechanism; an accommodation part provided on a sidewall of the housing and accommodating a drive circuit for driving the electric motor; a lid contacting the accommodation part and fastened to the accommodation part by a fastening portion; a sealing member sandwiched between the accommodation part and the lid so as to seal between them. The accommodation part has a wall standing from the sidewall of the housing, and a step is provided on a standing end surface of the wall orthogonal to a standing direction of the wall, at a midway position from an inside toward an outside of the accommodation part.

Abstract: A sealed compressor has an outer housing and a separator plate received within the outer housing. The separator plate defines a suction chamber and a discharge pressure chamber within the outer housing. A locating plate is positioned within the suction pressure chamber. The locating plate has a plurality of positioning locations for receiving separate compressor housings. The separator plate has a plurality of positioning openings for receiving the separate compressors. A plurality of compressors are each received within their own housing, and include compressor pump units. The plurality of compressors extend between the openings in the locating plate and through the openings in the separator plate. The separate compressors deliver compressed refrigerant into the discharge pressure chamber.

Abstract: A sealed compressor comprises an electric component; a compression component actuated by the electric component; a sealed container accommodating the electric component and the compression component; a suction pipe provided to suction a refrigerant into the sealed container; and a suction muffler having an inner space communicating with a compression chamber of the compression component and a suction port through which the refrigerant is suctioned into the inner space; a communicating passage for providing communication between the suction port of the suction muffler and the suction pipe, the communicating passage being made of a flexible material; and at least one cut portion provided in an end portion of the communicating passage at the suction pipe side such that the cut portion cuts a portion of the end portion.

Abstract: A sealed compressor comprises a sealed container: an electric component provided inside of the sealed container; a compression component actuated by the electric component; a suction pipe provided inside of the sealed container to suction a refrigerant gas from outside to inside of the sealed container; and a suction muffler having an inner space; wherein the suction muffler includes: an inlet pipe, one end portion of which opens inside of the sealed container and the other end of which has an outlet opening portion which opens in the inner space of the suction muffler; an outlet pipe, one end portion of which has an inlet opening portion which opens in the inner space of the suction muffler and the other end portion of which communicates with a compression chamber of the compression component; wherein the outlet opening portion of the inlet pipe and the inlet opening portion of the outlet pipe are disposed so as to face each other, and an opening area of the inlet opening portion of the outlet pipe is smalle

Abstract: An electrical submersible pump assembly for use in a well, including a well having a high gas-to-liquid ratio has a motor, a hollow, tubular drive shaft which drives the pump, and a liquid-gas separator assembly upstream of the pump intake. The liquid-gas separator has a hollow tubular portion, which communicates with the open, lower end of the drive shaft, openings through its sidewall, and a closed lower end. The sidewall also includes at least one outwardly extending projection shaped for urging liquid contained in a liquid/gas mixture flowing towards the pump outwardly, away from the sidewall openings. Preferably, the outwardly extending projection comprises a helical blade which, using either the well casing or a separate sheath, defines a helical channel through which the oil-gas mixture flows prior to reaching the pump intake.

Abstract: An electric pump comprises an outer housing including a motor cavity and a controller cavity separated by a partition wall. An inner housing is positioned within the motor cavity of the outer housing. One of the inner and outer housings includes radially extending ribs positioned adjacent to the other of the inner and outer housings to define a coolant flow path between the inner housing and the outer housing. The flow path is partially defined by the partition wall. An electric motor is positioned within the inner housing and includes a hollow rotor shaft driving a pump member. The hollow rotor shaft forms a portion of the coolant path and interconnects a volume between the inner and outer housings with a low pressure cavity containing the pump member. A controller is positioned within the controller cavity in heat transfer relation with the partition wall.

Abstract: The present invention provide an axial flow fan which comprises an impeller having a plurality of blades, a motor arranged to rotate the impeller, a casing accommodating the impeller and the motor, and a lead wire for supplying electric power to the motor, wherein the casing comprises a cylindrical housing, a motor base installing the motor, and a plurality of spokes connecting the housing with the motor base, and wherein the plurality of spokes include a spoke having a straight shape and a spoke having a curved shape convexly toward a rotational direction of the impeller.

Abstract: A pump aggregate (A) comprises a housing (1, 2, 4), a high-pressure pump (5) and a low-pressure pump (6) disposed in the housing, an oil-immersed electric motor (7), a return connection point (8) connected to a return line (9), and a valve arrangement (V) mounted between separated discharge outlet ports of both pumps (5, 6) and a pressure connection point (P). The valve arrangement (V) comprises at least a low-pressure change-over valve (U), a check valve (R) for combining discharge flows of both pumps (5, 6), and a system pressure-limiting valve (DB). At least the low-pressure change-over valve (U) and the check valve (R) are arranged in an interior of the housing (1, 2, 4) and are connected so that the discharge flows of both pumps (5, 6) are combined in the housing interior for a single pressure outlet (13, P?) of the housing, and wherein the system pressure-limiting valve (DB) is connected to the pressure outlet and is mounted on an exterior of the housing.

Abstract: A blower includes a casing having an air inlet, an electric motor having a rotor and a stator, an impeller driven by the motor, and a diffuser for directing air from the impeller. The impeller and the diffuser are received in the casing. The impeller has a base and blades supported by the base. The diffuser has a plate like portion with diffuser vanes surrounding the impeller. Inlet angles of the impeller blades is between 20˜30 degrees and outlet angles of the impeller blades is between 26˜38 degrees.

Abstract: A system includes a motor coupled to an energy source and coupled to a hoist pump. During one mode of use or operation, the motor cars receive electricity from the energy source and provide mechanical power to the hoist pump. A method includes directing a motor to mechanically couple to the hoist pump, and directing electrical power to flow from an energy source to the motor, and thereby to control the speed of hoist activity.

Abstract: A motor-driven compressor includes an electric motor, a compression mechanism driven by the electric motor to compress refrigerant, a housing accommodating the electric motor and the compression mechanism, and a support having a mounting to be fastened to an object by a fastener. One of the housing and the support has a projection and the other of the housing and the support has a recess that is engaged with the projection through a vibration damper so that the support supports the housing.

Abstract: A fluid pump system has a housing having a housing cover removably connected to a housing base. A plurality of fluid pump assemblies are inside of the housing. Each fluid pump assembly has an electric motor operatively connected to a fluid pump. Each fluid pump has a fluid inlet extending through a wall of the housing to an exterior of the housing and a fluid outlet extending through the wall of the housing to the exterior of the housing. An electrical component inside of the housing is electrically connected to each electric motor. The electrical component has an electrical connector extending through a wall of the housing to connect to a source of electrical power. The fluid pump system can dispense three different fluids, such as two detergents and a fabric softener in a laundry machine.

Abstract: In a motor for a compressor and a compressor having the same, when an aluminum coil with a low tensile strength is employed as a winding coil of the motor, upon connecting a terminal having serrations onto the aluminum coil, a reinforcing wire having a relatively high tensile strength is pressed onto the serrations together with the aluminum coil, whereby the aluminum coil can be prevented in advance from being cut off by a pressing force and accordingly a cut-off defect of the motor employing the aluminum coil can be prevented, thereby improving reliability and reducing a fabricating cost of the motor. Consequently, the reliability of a reciprocal compressor having the motor for the compressor can be increased.

Abstract: A rotor blade pitch adjustment device for a wind power installation includes a motor/pump unit whose rotation speed and direction are variable and which is connected for fluid-flow purposes to a hydraulic actuator via a hydraulic open-loop/closed-loop control system. The actuator is mechanically coupled to at least one rotor blade of the wind power installation in order to rotate the rotor blade about its longitudinal axis. An electrical control circuit, which comprises an emergency power supply device, is provided for operation of the motor.

Abstract: A pump for pumping viscous liquid. The pump includes a body, an elongate core, and a tube surrounding the core. A stepper or servo motor mounted on the body has a selectively rotatable output shaft. A transmission operatively connecting the motor output shaft and the elongate tube reciprocates the tube between a raised position and a lowered position. An inlet check valve defining an expansible lower chamber is oriented to open during each downward pumping stroke so liquid enters the lower chamber. The pump includes a pump chamber and a feed passage connecting the lower chamber to the pump chamber. The passage has a check valve oriented to open during each upward stroke to deliver liquid from the lower chamber to the pump chamber. An outlet passage connected to the pump chamber permits liquid to flow from the pump chamber to an outlet on each upward and downward stroke.

Abstract: A synchronous electric motor drive system capable of driving at speeds near zero is provided. An energization mode determination unit switches six energization modes successively based on a terminal potential detected of the de-energized phase of a three-phase synchronous electric motor or on a stator winding wire connection point potential (neutral point potential) detected of the three-phase synchronous transmission unit. A voltage command correction unit corrects by a correction amount ?V an applied voltage command destined for the synchronous electric motor to supply the synchronous electric motor with a repeated waveform of a positive pulse, negative pulse, and zero voltage as a line voltage waveform of the energized phases in each of the six energization modes, the positive pulse voltage being polarized to cause the synchronous electric motor to generate a forward rotation torque, the negative pulse voltage causing the synchronous electric motor to generate a reverse rotation torque.

Abstract: A centrifugal blood pump device includes a housing, a centrifugal pump section having an impeller which rotates in the housing to send blood by centrifugal force upon rotation, an impeller rotation torque generation section for attracting a magnetic member of the impeller and rotating the impeller, and a plurality of grooves for hydrodynamic bearing provided on an inner face of the housing on the impeller rotation torque generation section side.

Abstract: A fuel supply apparatus includes an electric pump, a control circuit, a lid component, and a connection component. The electric pump has a pressure raising part which raises a pressure of fuel in a fuel tank. The control circuit controls electric power supplied to the electric pump, and is arranged on the lid component. The connection component connects the lid component and the electric pump with each other, and defines a communicating path inside. A fuel outlet part of the electric pump and a circulation space of the lid component communicate with each other through the communicating path defined in the connection component.

Abstract: An object is to provide a motor-driven compressor capable of reducing cost required when a failure occurs in part of components configuring an inverter device. A power substrate assembly 50 is removably fixed to a housing body 10 in an inverter accommodation chamber 13, and a control substrate assembly 70 and a filter circuit assembly 90 are removably fixed to a cover 30. Therefore, when the cover 30 is removed from the housing body 10, the power substrate assembly 50, the control substrate assembly 70, and the filter circuit assembly 90 can be independently removed from the housing body 10 or the cover 30, and new power substrate assembly 50, control substrate assembly 70, and filter circuit assembly 90 can be independently mounted on the housing body 10 or the cover 30.

Abstract: A multiple stage variable speed blower for Continuous Positive Airway Pressure (CPAP) ventilation of patients includes two impellers in the gas flow path that cooperatively pressurize gas to desired pressure and flow characteristics. Thus, the multiple stage blower can provide faster pressure response and desired flow characteristics over a narrower range of motor speeds, resulting in greater reliability and less acoustic noise.

Abstract: A pump includes: (a) an elongated pump housing having first and second ends; (b) a primary impeller mounted in the housing for rotation about an axis, the impeller comprising a plurality of vanes whose outer tips define an impeller plane; (c) an inlet disposed in fluid communication with the primary impeller; and (d) an annular volute housing communicating with the primary impeller and with an outlet, where the volute housing is axially offset from the impeller plane.

Abstract: A centrifugal pump has at least one impeller, a pump housing and an electrical motor. The pump has a Q-H pump curve having a head H0 at zero flow and a head Href corresponding to the highest hydraulic power, and that Href is greater than H0. The pump has low energy consumption rate, especially at low flow corresponding to the conditions in which the pump is operated most of the time. Thus, the pump according to the invention is less energy consuming than the prior art centrifugal pumps.