An axial flow vacuum pump for evacuating a chamber in a semiconductor manufacturing process comprises a rotor having a plurality of rotor blades and a stator having a plurality of stator blades, wherein the rotor blades and stator blades have a curved shape.

An axial flow vacuum pump for evacuating a chamber in a semiconductor manufacturing process comprises a rotor having a plurality of rotor blades and a stator having a plurality of stator blades, wherein the rotor blades and stator blades have a curved shape.

A motor assembly that includes a motor having a motor casing, a rotatable shaft extending from said motor casing to a shaft length and a hub coupled to said rotatable shaft, the hub having a circumferential skid surface disposed immediately proximal to the motor casing and having a channel configured to seat a propeller, when a propeller is present, wherein a bending moment applied to the shaft through the hub results in the circumferential skid surface contacting said motor casing.

A cooling fan includes a hub, a plurality of blades, and a plurality of flow disturbing elements. The blades are arranged on a peripheral surface of the hub; each of the blades has a leading edge and a trailing edge opposite to the leading edge, and each of the blades has at least one flow disturbing element arranged at the trailing edge. Each of the flow disturbing elements includes an engaging part and an extending part opposite to the engaging part; the engaging part of each of the flow disturbing elements is connected to the trailing edge of the corresponding blade, and the extending part of each of the flow disturbing elements extends outwardly toward a direction away from the trailing edge of the corresponding blade.

In an aspect there is disclosed, a fan arrangement for a duct, the fan arrangement including a housing having an inlet and an outlet adapted to communicate air with the duct and an axially rotatably driven impeller supported within the housing between the inlet and the outlet. The impeller includes a hub carrying a plurality of blades that span in a radial direction outwardly of the hub, the plurality of blades being shaped to urge air between the inlet and the outlet. The plurality of blades may have a tip solidity ratio in the range of about 0.8 to 1.2, and each of the plurality of blades may have a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees and a substantially constant thickness. An impellor, a blade, ventilation system and related methods are also disclosed.

A ceiling fan or blade thereof can include a fan motor for rotating the blade. The blade can include an airfoil body having an outer surface extending between a leading edge and a trailing edge, and a root and a tip. The blade can be separated into three distinct cross sections including a first cross section as a lifting cross section, a second cross section as a flat cross section, and a third cross section as a transition section between the first and second cross sections.

A fan includes an air cylinder and an air outlet hood. An interior of the air cylinder is hollow to form a hollow cavity. The air cylinder has an air inlet and an air outlet. The air outlet hood is detachably disposed on the air outlet. The air outlet hood is provided with an annular air outlet for air outlet. An outer ring and/or an inner ring of the annular air outlet is formed with an annular guide rib extending toward the air inlet. The annular guide rib is configured to make an airflow cross section adjacent to the annular air outlet gradually decrease, so as to make an airflow in the air outlet hood cohesive, thereby increasing an air outlet speed of the annular air outlet. A hair dryer having the fan is also disclosed.

Each of a plurality of blades of a turbofan includes a thick wall portion, a thin wall portion and a stepped portion. The stepped portion is formed between the thick wall portion and the thin wall portion. A plate thickness of the stepped portion is progressively decreased toward a positive pressure surface of the blade in a direction that is directed from the thick wall portion toward the thin wall portion. In the blade, a first curved surface forms a negative pressure surface of the thick wall portion, and a second curved surface forms a negative pressure surface of the thin wall portion while the second curved surface is located on a side of the first curved surface where the positive pressure surface of the blade is placed, and a negative pressure surface of the stepped portion connects between the first curved surface and the second curved surface.

A ceiling fan having double-layer blades includes a motor unit, a blade frame unit, a first blade unit, and a second blade unit. The blade frame unit has a blade frame body. The first blade unit includes a plurality of first blades. The second blade unit includes a plurality of second blades. The first blades and the second blades surround the outside of the blade frame body, so that there is no need for the motor unit to provide a motor housing for connecting the first blades and the second blades, thereby saving costs and installation costs. With the arrangement of the first blades and the second blades, the ceiling fan can increase the current of air for cooling.

A ceiling fan including a retention system and method of redundantly retaining a ceiling fan can include a ceiling fan motor assembly including a hollow motor shaft at least partially surrounded by a motor housing. A retainer plate is provided at the bottom of the motor housing including an opening. A retainer rod extends through the opening in the retainer plate and secures to the retainer plate. A support cable couples to the retainer rod to suspend the retainer plate from a structure, wherein the retainer plate is configured to redundantly retainer the ceiling fan.