A blower is provided that may include a fan that creates airflow; a lower body forming an inner space in which the fan may be installed, and having at least one suction hole through which air passes; an upper body positioned above the lower body and including a first upper body forming a first inner space that communicates with the inner space of the lower body, and a second upper body forming a second inner space that communicates with the inner space of the lower body and spaced apart from the first upper body; a space formed between the first upper body and the second upper body and opened in a frontward-rearward direction; a first opening formed through a first boundary surface of the first upper body facing the space; a second opening formed through a second boundary surface of the second upper body facing the space; and a door assembly including a first door installed at the first upper body and that opens and closes the first opening, and a second door installed at the second upper body and that opens and closes the second opening.

An EMI attenuation device includes a housing stator, a fan rotor, and an electrical bridge therebetween. The housing stator has an aperture therethrough, and at least a portion of the housing stator is electrically conductive. The fan rotor is adjacent to the aperture and has a rotational axis relative to the housing stator and a proximate surface proximate the housing stator. The fan rotor is electrically conductive, and the proximate surface is continuous around a rotational direction of the fan rotor. The electrical bridge is between the proximate surface of the fan rotor and a contact surface of the housing stator.

A fan includes an electric motor and a fan wheel drivable or driven by the electric motor, arranged within its housing. The underside of the housing has an opening for an electric outlet, and a side the housing has a bracket, thereby forming a bushing. An electric line is arranged at least partially at the underside of the housing and is guided through the bushing, and a cover element is arranged at the underside of the housing. The cover element has a first section and a second section. The cover element is arranged at the underside of the housing in such a way that the first section is at least partially arranged in the bushing and clamps the electric line in the bushing while forming a strain relief, and that the second section covers the opening.

A blower may include a first case and a second case provided above the first case and having a first tower and a second tower that have a passage therebetween. A display assembly is received in the second case at a position that does not interfere with air flowing in the passage. An inner surface of the second tower and an outer surface of a diffuser define a space in which the display assembly is received.

A blower has a blower housing of clamshell construction, including two housing members having a scroll back wall molded with radial draft, an impeller and a motor within the housing, and a static tap connected to the housing. The impeller has a backplate with a backplate back surface region of substantially the same radially converging shape as that of a front surface region of the scroll back wall formed by the radial draft, providing a substantially uniform axial gap between the backplate back surface region and the scroll back wall. The impeller has a ring connected by a skirt to the back plate to define a stepped area behind the ring. The impeller includes impeller blades extending forwardly from the impeller backplate and the ring and back fins extending rearwardly from the ring. The blower has a scroll width of about twice an impeller exhaust width.

A blower may include a first case and a second case provided above the first case and having a first tower and a second tower that have a passage therebetween. A display assembly is received in the second case at a position that does not interfere with air flowing in the passage. An inner surface of the second tower and an outer surface of a diffuser define a space in which the display assembly is received.

A fan inspection jig includes a jig assembly having multiple spring abutment pillars for holding two sides of a fan (or a series fan) to make the fan or the series fan positioned in a suspending position. A vibration sensor is disposed in at least one of the spring abutment pillars of two sides of the fan for measuring a vibration signal of the fan in operation.

A vacuum pump includes a housing, a rotor cylindrical portion, and a stator cylindrical portion. The housing has an inlet port for sucking gas and an outlet port for discharging the sucked gas. The rotor cylindrical portion is housed in the housing. The stator cylindrical portion is housed in the housing, and is arranged to face the rotor cylindrical portion. A screw groove is formed on one of opposing surfaces of the stator cylindrical portion and the rotor cylindrical portion. The groove depth D of the screw groove is smaller at an end on an exhaust side than at an end on a suction side. The decrement of the groove depth D is greater on the suction side than on the exhaust side.

A control circuit including a motor drive unit and a processing control unit is provided. The motor drive unit includes a drive current for a motor according to a modulation signal, and the motor is powered by a storage battery. The processing control unit obtains an actual speed of the motor, calculate the modulation signal by comparing the actual speed and a target speed, and transmit the modulation signal to the motor drive unit. Also, the modulation signal is used to control rotation of the motor by modulating the drive current, so that the actual speed tends to be equal to the target speed.

A blower has a blower housing of clamshell construction, including two housing members having a scroll back wall molded with radial draft, an impeller and a motor within the housing, and a static tap connected to the housing. The impeller has a backplate with a backplate back surface region of substantially the same radially converging shape as that of a front surface region of the scroll back wall formed by the radial draft, providing a substantially uniform axial gap between the backplate back surface region and the scroll back wall. The impeller has a ring connected by a skirt to the back plate to define a stepped area behind the ring. The impeller includes impeller blades extending forwardly from the impeller backplate and the ring and back fins extending rearwardly from the ring. The blower has a scroll width of about twice an impeller exhaust width.