Categories: Machinery

Design and principle of operation of industrial and domestic fans

Today, in almost every home you can find a fan of various designs. Exhaust system in the kitchen, air conditioners, coolers in PC, forced ventilation systems of various rooms in the home and at work - all these devices will not be able to function properly without this important ??component. In this article we will get acquainted with the principle of operation of different fans, as well as learn their advantages and disadvantages.

Axial or axial

In appearance, a fan of this type is a metal casing in the form of a cylinder, where the wheel with blades of various configurations is located, mounted on one drive shaft. The case has special perforations for reliable fastening on a place of use. The air flow comes parallel to the axis of rotation. At the entrance is a collector - it improves the aerodynamics of the product during operation. How the product works, can be explained quite simply.

An electric motor mounted on a special frame spins the fan impeller, planted on the same shaft with him.
Impeller speeds are identical to the drive parameters set by the manufacturer.
The blades are fixed to the hub in this way, to capture layers of air and direct them along the axis. The scope of the blades has no clear gradations: in everyday life use a few centimeters in length, and in industry - up to several meters.

The device is protected by a fine mesh, which eliminates the ingress of objects, capable of damaging the structure, and for security purposes.

The efficiency of axial units is much higher than other products, the pressure of the air mass and its amount can be adjusted by changing the angle of attack of the blades. This type of fan is used to move very large air masses at low counter-resistance.

The following is a drawing of an axial fan, where 1 - frame; 2 - impeller; 3 - shoulder blades; 4 - electric motor.

advantages:

relatively low energy consumption;
the mechanism works properly without human intervention;
does not require much space for installation.

shortcomings:

the product works properly only with air without impurities;
high vibration and noise accordingly.

Usually, such products are installed outside the facilities, so that the noise of the fan does not interfere with the production process.

radial

Radial or centrifugal device differs from other types of unusual spiral casing design, in which the impeller is located, which compresses air masses during rotation, moving them in the direction from the center to the peripheral part. The flow enters the casing under the influence of centrifugal forces from the rotation of the wheel with the blades.

The blades are welded to the hollow cylinder around its perimeter strictly parallel to the axis of rotation by means of steel disks, their ends are bent inward or outward, depending on the direct purpose of the device. Rotation can be performed in any direction - it depends, as a fan, and what tasks are set before him (injection or extraction).

The main components of the radial fan are shown in the drawing below, where 1 frame; 2 - impeller; 3 - impeller blades; 4 - fan axis; 5 - bed; 6 - engine; 7 - exhaust pipe; 8 - flange of the suction pipe

pros:

withstands decent overload;
energy saving to 20%;
small diameter of the impeller;
low speeds of rotation of a drive shaft.

cons:

high vibration and noise;
demanding quality of manufacturing rotating parts.

channel

This type of fan is installed in the wall, and only its lattice is visible in the room, followed by air ducts, through which the exhaust air goes outside or to the filtration and purification system, then returns.

To learn all the nuances of the fan of this type, watch the video. It explains in detail the functional features of the duct fan.

A multilayer fabric is used to make the housings of these original devices, consisting of steel, durable plastic or combinations thereof. The connection is made by spot welding or fasteners.

advantages:

finishing of several rooms at the same time;
carry out the addition of fresh air from the street;
variations in air flow.

cons:

when served in all rooms, mixing takes place, if someone smokes, then this smell gets into other rooms;
there is no independent temperature control;
high installation cost, which includes the price of pipelines;
to clean filters, need a hatch to work.

On a side note! Very high performance characteristics of such fans due to their original structure make them popular. Ducts are installed in residential buildings, large shopping malls and some types of production.

tangential

Products of this type consist of a case, having a diffuser and a pipe, original looking impeller, very similar to a combine harvester, only greatly reduced in size with forward-curved parallel blades.

The principle of operation of a tangential fan is based on the repeated passage of air through the working parallel blades in the transverse direction, which is the original nuance of this design. exept this, these devices are quite high in terms of aerodynamics.

The following is a simplified drawing of a tangential fan, where 1 - inlet pipe, 2 - impeller, 3 - output diffuser.

Thanks to that, that they can create a flat flow of air masses, they are often used for "warm shutters", having a shaft of rotation in a vertical position.

advantages:

very high efficiency;
the ability to direct the flow in any direction;
creating a uniquely flat and uniform air flow.

This type of product has a fairly low noise level with a fairly high air consumption per unit time.

bladeless

The operation of the bladeless fan is based on the principle of operation of the jet engine: there is a turbine, whose work promotes rapid air circulation in the room. The design of this fan is quite original: powerful base, oval working part, visually very similar to the air intake of a modern aircraft engine.

The contour ring has a number of perforations, through which air escapes, capturing layers of air masses according to the law of aerodynamics. A powerful turbine can pump up to 20 cubic meters of air per second, what similar devices cannot do is the main difference of this type of products.

The speed passing through the ring of air can reach very decent values, manufacturers of such original equipment assure, that it may exceed 90 km / year.

Positive qualities:

assembly and installation speed;
high security;
big savings;
remote control;
LED backlight, successfully replaces the night light;
the drive brushes are made of magnetic alloy, which eliminates the accumulation of dust on them;
very unusual design.

cons:

high cost;
strong noise effect due to high flow rate.

Such original products are considered a kind of floor fan.

Household

For the implementation of normal ventilation in the apartment or your own home use a special design of household fans, because they must work efficiently and not let back draft into the room along with all the negative components.

The electrical circuit of the fan differs depending on its type and purpose - it is attached to the operating instructions of the product. A similar power supply connection is virtually unchanged, except for some device-specific nuances.

Household fans are also understood to be familiar to all of us designs for cooling indoor air. When performed, they can be table or floor type, standard equipment - electric drive, impeller and restrictive gratings for safety.

The functions of the household fan can be expanded due to efficient additions:

humidification of air;
ionization system, which is very useful for the younger generation and the elderly.

These improvements increase the cost of the product, but have a positive effect on the microclimate of the room, especially during the outbreak of seasonal diseases.

pros: