The fan is centrifugal. Principle of operation and scope

Complex systems of ventilation and air conditioning are designed taking into account many factors. Subsequent installation requires special attention: air ducts, air heaters, sound attenuators, diffusers, grills and valves must be in place, and fans and air conditioners must have adequate power.

A fan, centrifugal or axial, in general can be called the heart of the system, because it pushes the air through the vessels of the system - the ducts in the right direction. Despite the fact that such units are necessary for performing the same function - forced air movement, each of them has a special design.

Centrifugal fan. The device, the principle of operation and distinctive features

This equipment consists of an impeller, which is fixed on a special shaft, inlet and discharge branch pipe and a spiral housing. Air (moving gas) is sucked by the collector and, getting into the fan case, is grasped by the blades of the rotating wheel. Thus, the direction of the air flow (gas) itself changes: from a straight line parallel to the axis, it becomes radial. Further, the effective centrifugal force propels the air through a special hole in the casing.

Such features of the operation of this unit became the reason for its name - the fan is centrifugal, it is also radial. Another "nickname" - snail - this equipment has received thanks to its spiral-shaped body.

Rotation of impeller in such fan can be right or left. The number of blades affects the type and purpose of the equipment. There is another nuance: in which direction are the blades turned (forward or backward) - this in some cases is of fundamental importance. For example, a centrifugal fan equipped with blades turned back allows saving up to 20% of electric power, and during its operation overloads on air consumption are permissible.

The vanes curved forward, in turn, allow to reduce the diameter of the wheel to which they are attached, and accordingly, the fan itself can be more compact. Another plus: the speed is less, and the noise level is reduced.

The centrifugal fan can be used in the system of forced drawing of dining rooms and laundries, in the metallurgical and chemical industries, at refineries. It should be noted that if you plan to move relatively clean air, not contaminated with harmful impurities, then enough "snails" made of carbon steel. In cases where explosive gases are present, equipment with a casing of aluminum alloy or cast iron is used. In enterprises where there is a need to remove air containing impurities of gases or aggressive vapors, it is recommended to install special fans. Their distinctive feature is that the inside, through which dangerous air will flow (impeller with blades, casing, shaft), are made of acid-resistant alloys of steel, plastic and aluminum. It is quite obvious that if a ventilation device requires specific equipment, in particular a centrifugal fan, the price for it will be higher than for a standard of carbon steel.