A gas turbine engine radial impeller includes first and second impeller portions that are secured to one another along a neutral bending plane of the radial impeller. A vapor cooling cavity is provided between the first and second impeller portions. The neutral bending plane is arranged in the vapor cooling cavity.

A compressor with negative coefficient of thermal expansion case material comprising a rotor having blades with tips, the case including an inner case comprising a negative coefficient of thermal expansion material, and a tip clearance located between the tips and the inner case; wherein the tip clearance is maintained responsive to a flow of air over the negative coefficient of thermal expansion material.

A fan module for a gas turbine engine is disclosed herein. The fan module includes a fan, a plurality of outlet guide vanes, and a fluid cooling system. The fan is adapted to rotate about a central axis to pass air at least in part aftward along the central axis and around an engine core of the gas turbine engine. The outlet guide vanes are spaced aft of the fan along the central axis and configured to receive the air passed aftward along the central axis by the fan. The fluid cooling system is configured to transfer heat from a fluid to the air from the fan to cool the fluid.

A vacuum pump comprising a turbomolecular stage and a drag stage, the vacuum pump comprising a stator and a rotor. The rotor comprises a turbomolecular rotor and a drag rotor attached together. The turbomolecular rotor comprises a hub from which a plurality of blades extend, the hub comprising a mounting portion for mounting to a spindle of a motor and a hollow cylindrical portion, the hollow cylindrical portion extending from the mounting portion towards an outlet end of the turbomolecular stage. The drag rotor comprises a cylindrical skirt and an attachment part extending away from the cylindrical skirt, the attachment part extending within the hollow cylindrical portion of the hub of the turbomolecular rotor and being attached thereto at a point that is closer to the mounting portion than to the outlet end of the turbomolecular rotor.

A fan motor comprises a motor mount, a motor part accommodated in an inner space of the motor mount, and an impeller disposed above the motor mount. The motor mount defines: an air discharge opening configured to discharge air discharged from the impeller to an outer space of the motor mount; a cooling flow path outlet disposed at the upper side of the motor mount at a position between the impeller and the air discharge opening; and a first cooling flow path inlet disposed at a position below the air discharge opening and the cooling flow path outlet. The fan motor further includes a guide that is configured to direct, to an upward direction, at least a portion of air that is discharged through the air discharge opening and introduced to the inner space through the first cooling flow path inlet.

A cooling system for a motor-compressor and a method for cooling the motor-compressor are provided. The cooling system may include a discharge assembly having a hub portion disposed radially outward of a rotary shaft of the motor-compressor. A plurality of arms may be fluidly coupled with and may extend generally tangential from the hub portion of the discharge assembly. The hub portion may define an annular volume fluidly coupled with the plurality of arms. The cooling system may also include a blower impeller disposed in the annular volume and coupled with the rotary shaft. The blower impeller may be configured to rotate with the rotary shaft and draw a cooling fluid into the discharge assembly.

A ceiling fan and a fan set are provided. The fan set includes an upper fixed plate, a lower fixed plate, and a plurality of fan blades. The upper fixed plate has a plurality of first through holes that are in a ring-shaped arrangement, and the lower fixed plate has a plurality of second through holes that are in a ring-shaped arrangement. The quantity of the second through holes is equal to the quantity of the first through holes, and the positions of the second through holes respectively correspond to the positions of the first through hole. Each of the fan blades has an assembly portion, a blade portion, and three fasteners. The fasteners pass through the first through holes and the second through holes such that each of the fan blades is fastened between the upper fixed plate and the lower fixed plate.

A turbo-molecular pump comprises: a rotor; stationary blades; a stator; a plurality of spacers; a heater disposed on the base; a temperature sensor for detecting a temperature of the stator; and a temperature regulation section for on/off controlling the heater based on a temperature detected by the temperature sensor to regulate the temperature of the stator so as to be a reaction product accumulation prevention temperature. At least one spacer arranged on a base side of the plurality of spacers is cooled by coolant, and the turbo-molecular pump further comprises a heat insulation member disposed between the base and the spacer arranged on the base.

A heat pump including a two-stage, high speed fluid compressor including a case having a fluid inlet and a compressed fluid outlet and containing a shaft rotatably mounted about a longitudinal axis, a first compression wheel and a second compression wheel mounted back-to-back on the shaft, the first compression wheel forming a first compression stage and the second compression wheel forming a second compression stage, and a motor positioned between the first compression wheel and the second compression wheel and arranged to rotate the shaft. The case includes an inner through housing extending coaxially to the longitudinal axis and inside which is arranged at least the motor, the inner housing having an inner wall arranged to form, with the motor, channels between at least the inner wall and the motor to cool the motor.

A fan noise suppression circuit may be coupled between a power source and a power input to at least one fan. The fan noise suppression circuit may include an adjustable current source coupled to the power source. The adjustable current source may provide a voltage output and a current output based on a power output of the power source. The fan noise suppression circuit may include a feedback controller coupled to an output of the adjustable current source. The feedback controller may be configured to compare the voltage output to a reference voltage and provide an error value to the adjustable current source, wherein the adjustable current source may adjust the current output based on the error value.