Industrial fans. Description and application
To ensure the proper working conditions of industrial enterprises, in industrial buildings and premises, general ventilation systems are used, which are divided into two main types.
Total ventilation provides fresh air access to the room, which is additionally filtered, cooling or moisturized, depending on the main fans used.
Exhaust ventilation is responsible for removing polluted air, playing the role of industrial hood. Expitable industrial fans are used together with supply, and their performance is calculated in such a way as to balance the pressure in the internal space.
General information about fans
By design and principle of action, fans are divided into two main types. Radial (centrifugal) and axial. There are also a number of modifications of radial fans. Diagonal, diametric (tangential), disc and other. In ventilation and heat.Power plants systems, radial, axial and diametral fans are most often used.
The radial fan is constructively located in the spiral case 3 of the working wheel 6, when the air entering the entrance pipe 1 is rotated, it enters the interlopter channels of the wheel and moves through these channels under the influence of centrifugal force, is assembled in a spiral case and then is supplied to the outlet pipe 2. When passing gas through the working wheel, its pressure and kinetic energy increase.
There are designs of a radial fan with the left and right direction of rotation of the working wheel. The operating wheel drive can be carried out directly from the shaft of the electric motor or through the cuneiform transmission.
The axial fan is a 2 blade operating wheel 1 shovel in a cylindrical housing, when the air entering through the input pipe is rotated under the action of the shoulder blades, it moves between them in the axial direction. The pressure and kinetic energy of the flow increase.
In the diametric fan, air movement occurs in the plane, the perpendicular axis of the rotation of the working wheel 2. Drum.Type work wheel with shovels bent forward. The fan housing resembles a radial fan housing.
The principle of operation of different types of devices
The main criterion for choosing a fan is its device and the principle of functioning. Design features and technical nuances determine the effectiveness of the device, the level of noise, the efficiency of work and the possibility of its use in certain conditions.
Most household fans belong to the group of axial devices. Their blades connected to the working part rotate around the central axis
In the group of axial fans there are independent devices and devices installed in the air ducts
In centrifugal fans, the working wheel rotates inside the housing, is driven by a motor located outside the system. Centrifugal devices mainly serve industrial and commercial facilities
Among household appliances there are non.Disabilities. According to the principle of action, they relate to centrifugal, which in design are with and without blades
Axial unit. Classic fan
The axial (axial) fan is widely operated in domestic ventilation systems of private houses, in the hoods of bathrooms, in complex exhaust variants, as an element of cooling of various equipment and electronics, as well as in aerodynamic pipes and turbibia engines in the field of aviation.
The design of models is characterized by simplicity of execution and small dimensions. Basic elements: cylindrical case, wheel with blades and drive. The inner diameter of the cylinder must provide unhindered revolutions of the working wheel. The interval between the blades and the case is limited to 1.5% of the length of the rotating blade.
Axial Fan animation | Howden
In order to lower hydraulic losses and improve aerodynamic characteristics, the structure is supplemented by a collector, diffuser and a fairing on both sides of the working wheel
Principle of action: rotating blades capture air and push it out along the axis of the impeller. The movement of air flows in the radial direction is almost absent. Equipment performance is regulated by turning the shoulder blades.
Distinctive features of axial models:
- Do not require a large area for installation;
- Economical electricity consumption;
- Low noise;
- Simplicity of operation and repair;
- Low cost.
The advantages of the work and use of axial fans have led to their wide popularity in everyday life. Cabinet models for cooling electrical appliances and portable axial units with a lattice are used.
To strengthen air exchange in the wall openings and other supporting structures, axial fans with a wall panel are installed. Devices are capable of functioning in two modes: absorption and injection of air
Centrifugal model. Strength and high power
Centrifugal (radial) fans are highly efficient. Units are able to generate high pressure and operate in harsh conditions. The design of the equipment includes the following elements.
Frame. Diffusion casing is made of sheet metal riveted or welded. The hollow case has a spiral shape of the snail, the design is provided with a suction and discharge pipes. To give stiffness, the casing is enhanced by nutrition or transverse stripes.
On top of the “snail” is closed with an additional box or sheathed with noise.Sounding panels. This is necessary to reduce noise during the operation of the ventilation installation
Working wheel. The lobed rotor consists of two disks, shoulder blades and hubs.
The design of the wheel determines the conditions for using the fan:
- Blessed. Transportation of flows with solid components;
- Single.Disc. The movement of air environments with small m of solid fractions;
- Double.Disc. Circulation of clean air masses in a different pressure range;
- Three.Disc. Ensuring bilateral absorption.
The wheel mount to the shaft occurs by means of hubs. The blades are fixed to the discs and hubs.
Shoulder blades. The working characteristics and effectiveness of the unit as a whole largely depend on the shape of the blades:
- Aerodynamic wing. Provides noiselessness, a good performance indicator, the stability of the device to high temperatures;
- Curved back. Prevent the accumulation of dust inside the fan, suitable for operation in an environment with high inhibition;
- Curved forward. Fans with “front” ribs are designed to work with a large volume of air and high pressure, differ in resistance to erosion;
- Radial. Installations of compact sizes with average efficiency, rotor guide are processed by a protective composition from erosion.
In wheels with “rear” blades, the difference in the indicators of static and complete pressure is not large, so their level of efficiency is high. Work efficiency reaches 80%.
Axial fan experts
Forward bent blades create a high speed of the air flow at the output. The unit retains 60% of efficiency. Plus “front” blades. Obtaining the desired parameters with smaller fan dimensions
In centrifugal units, air enters the axial direction, pushes out. In radial. Air masses under the influence of centrifugal forces move in a cylindrical case.
The whole process can be divided into several stages:
- When the wheel rotates, the air between the space of the shoulder blades rushes to the edge of the rotor.
- As a result, a low pressure zone is formed in the center of the wheel. This leads to the absorption of air masses from the outside.
- In the center of the camera, air flows change the direction from axial to radial, entering the compartments between the blades.
- Due to rapid rotation, air masses rush to the internal wall of the case.
- Kinetic energy is partially converted into compression energy and the air speed is reduced. A voluminous air flow is collected inside the “snail” and excess pressure is formed.
- The gaseous mass rushes to the output pipe, enters the pipeline, and then into the work area.
Which fan is better to choose
Before buying a ventilation device for home, you need to know what parameters you need to pay attention to.
So, the advice of experts when choosing household fans:
- The size of the blades. The optimal diameter is recommended from 10 to 15 cm, while they should be protected by a screen with small holes.
- Power. The larger this indicator, the greater the volume can process this device.
- Noise level. You especially need to pay attention to such a parameter when buying cheap models.
- Functionality. Most fans perform additional functions, such as ionization, heating, they also have a timer, a remote control and another.
- Control. Sensor or button navigation.
- Brown space. The largest area for such cooling devices is 50 m 2.
- Angle of rotation. Many models have an angle of inclination 45-360 degrees.
- Modes. Different speeds when moving the air flow are very important, since this creates comfort when in the room.
- The location of the fans. At the place of accommodation, devices are window, wall or ceiling.
Let us consider in more detail which models are better for a bathroom and kitchen.
Extract kitchen fans should have a high power that can not only update air in the kitchen, but also withstand high temperatures. Such a suitable device is the Wolter KA KATD 225-4 STB model.
At the same time, the dialing device in the kitchen has the following parameters:
And also for kitchen fans is characterized by the fact that they withstand the temperature of moving air up to 95 degrees.
An ideal option when selecting a lifting device for the bathroom will be a device with a installed humidity sensor. At the same time, the Silent-100 CHZ model from “Soler Palau” is especially popular.
It is most positively evaluated by domestic users for what it has:
- Low level of noise in work (up to 24.5 dB);
- Long service life;
- It has a high power (95 m3/h);
- Built.In timer;
- Relatively small energy consumption (80 watts).
But for a bathroom with a large area of more than 5 m 2, there should be a sufficient extract of the exhaust air, so you need to choose a more productive fan. This is the EAF-150 device from Electrolux.
It is distinguished by the following characteristics:
You can choose the desired mode for him by reinstalling the jumper placed inside the timer box.
The exhaust device for the kitchen and the bathroom will have advantages if all the parameters are selected correctly. And then this multifunctional device will create convenience in the room and a pleasant microclimate.
Channel fans for circular duct ducts
Round duct fans are designed to work as part of ventilation systems designed from circular ducts. Their types of size correspond to the geometric parameters of standard ventilation ducts. Over, in comparison with rectangular models of similar working section parameters, round duct fans for extract and air flow are won by performance. As an example, you can cite the Round VKK-250M fan, which, with a power consumption of 135 W, gives out a productivity of 1050 m3/h, while the rectangular model of the VKP-40-20-4D demonstrates 1200 m3/hour, but with a power of 330 watts.
Depending on the constructive device and the principle of action, the following types of channel fans of the round section are distinguished:
Diagonal channel fan device
In the diagonal channel fan, the impeller has its own special shape, which is shown in the figure. Due to its form, it is subjected to a large static air pressure, which is provided by centrifugal force. Unlike axial duct fans, in the diagonal fan, the air flow is directed along the axis. Thus, the diagonal channel fan is a combination of axial and radial fans technologies. The air in it begins movement along the axis, and then changes direction to the radial (across the axis). In this version of air supply, there are disadvantages, but the design of the diagonal duct fan allows you to achieve an efficiency of 80%.
This type of fan is installed in the wall, and only its grill is visible in the room, then the ducts go through which the spent air is directed out or to the filtration and cleaning system, and then returned back.
To find out all the nuances of the fan of this type, watch the video. It explains the functional features of the channel fan in detail.
For the manufacture of cases of these original devices, a multilayer canvas is used, consisting of steel, durable plastic or their combinations. The connection is taking place by point welding or fasteners.
- When serving, mixing occurs in all rooms, if someone smokes, then this smell falls into other rooms;
- There is no independent temperature control;
- High cost of installation, which includes the price of pipelines;
- To clean filters, you need a hatch for work.
On a note! Very high characteristics for the operation of such fans, due to their original structure, make them popular. Danal fans are installed in residential buildings, large shopping centers and on some types of production.
Which fan is better: axial or radial
A clear answer to the question which fan is better. Axial or radial.No. This is due to the fact that the choice of a particular type of fan mainly depends on the operating conditions, the required air flow values, power and productivity of the device.
So, radial fans, unlike axial fans are most often used in industry, and axial are installed in air conditioning and ventilation systems (shops, offices, residential buildings, etc.D.). However, this does not mean at all that radial fans cannot be used in everyday life, and axial fans. In industry.
The axial fan, in contrast to the radial, distributes air from its axis into the surrounding space around the circle. The radial fan in comparison with the axial lies in the fact that it directs the air flow from the arc of the circle to the center. The difference between the axial device is the spread of the air flow from the axis to the space around the circle. In other words, the main difference in the axial and radial fan is the direction of the air in their device.
For large industrial installations, radial fans are best suited, and axial are most often used in places of simple and quick ventilation.