Provided is a vacuum pump in which no finish processing has to be carried out after shaping of a cylindrical rotor even in use of a cylindrical rotor obtained by shaping a fiber-reinforced plastic material into a cylindrical shape. The vacuum pump has a turbo-molecular pump section and a thread groove pump section. The upper end section of a cylindrical rotor, which is obtained by shaping a fiber-reinforced plastic material into a cylindrical shape, of the thread groove pump section, is joined to the lower end section of a rotor of the turbo-molecular pump section. A joining portion of the rotor of the turbo-molecular pump section and the cylindrical rotor of the thread groove pump section is disposed upstream of an exhaust passage. As a result, finish processing does not have to be carried out after shaping of the cylindrical rotor. If finish processing is performed after shaping of the cylindrical rotor a resin may be coated onto a rugged portion of the cylindrical rotor, or fibers may be helically wound at a winding angle not greater than 45 degrees.

A pump unit includes a pump housing having a valve assembly positioned on a wall thereof and adapted to be coupled to an inflatable device, and an air control assembly that is housed inside the pump housing. The air control assembly includes an impeller section that houses an impeller, and has an air inlet and an air outlet. The air control assembly further includes a motor housing that houses a motor, the motor housing having an air vent that communicates the interior of the motor housing with the air inlet and the air outlet, and a vent opening that communicates the interior of the motor housing to the environment. The air outlet is aligned with the valve assembly when the pump unit is operated in the inflation mode, and the air inlet is aligned with the valve assembly when the pump unit is operated in the deflation mode.

A vacuum pump comprises stator elements in a pump housing. The stator elements cooperate with rotor elements. The rotor elements are held by a rotor shaft, wherein the rotor shaft is mounted in the pump housing via bearing elements. The bearing element is surrounded by a supporting element, wherein the supporting element comprises an inner portion, an outer portion and a plurality of spring arms connecting the inner portion (28) to the outer portion. Each spring arm comprises at least one hollow space.

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 system comprising: a liquid ring pump comprising a chamber and an impeller mounted within the chamber; a driver configured to drive the liquid ring pump so as to cause the impeller to move within the chamber; and a controller configured to, responsive to determining that a speed of the impeller relative to the chamber is below a threshold speed or is zero, control the driver to drive the liquid ring pump so as to cause the impeller to move within the chamber.

A vacuum pump, and a waterproof structure and a control apparatus applied to the vacuum pump which improve efficiency of on-site maintenance work and prevent water from penetrating into a connector connecting portion when a cover is removed during circuit separation or the like. When performing maintenance work, after a chassis of a control apparatus is lowered by around several tens of millimeters, the chassis of the control apparatus is pulled out in a radial direction of a pump. Accordingly, a pump main body and the control apparatus can be readily attached and detached even when sufficient empty space is not available in an axial direction of the vacuum pump. A wall portion is circumferentially protrusively provided in side portions of the base portion and the control apparatus. Furthermore, a sealing member and a lid are inserted into a gap. Therefore, water droplets cannot easily penetrate into the gap.

A vacuum pump includes a housing, a rotatable shaft extending in an axial direction within the housing, a first pumping arrangement including a first stator arrangement and a first rotor arrangement, and a second pumping arrangement including a second stator arrangement and a second rotor arrangement. The vacuum pump further includes a spacer arranged between the first pumping arrangement and the second pumping arrangement. The spacer is coupled between the first stator arrangement and the second stator arrangement and is configured to provide a defined elasticity in the axial direction allowing an elastic deformation of the spacer in the axial direction.

A side channel compressor for compressing gas includes a housing, which forms a side channel, and an impeller drive arranged in the housing. The housing forms a feed channel fluidically connected to the side channel for feeding gas to the side channel and a discharge channel for discharging gas out of the side channel that is fluidically connected to the side channel. The feed channel branches into two separate channel arms each extending along a channel arm center axis. The housing is subdivided along a separating plane into first and second housing parts which sealingly lie against one another. The discharge channel is passed through between the two channel arms and either a first or second discharge channel part of the discharge channel, opens out on a connecting surface of the first or second housing part forming a gas outlet opening arranged apart from the separating plane.

A side channel compressor for compressing gas includes a housing, which forms a side channel, and an impeller drive arranged in the housing. The housing forms a feed channel fluidically connected to the side channel for feeding gas to the side channel and a discharge channel for discharging gas out of the side channel that is fluidically connected to the side channel. The feed channel branches into two separate channel arms each extending along a channel arm center axis. The housing is subdivided along a separating plane into first and second housing parts which sealingly lie against one another. The discharge channel is passed through between the two channel arms and either a first or second discharge channel part of the discharge channel, opens out on a connecting surface of the first or second housing part forming a gas outlet opening arranged apart from the separating plane.

A fan motor has 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.