When arranging forced ventilation systems, special mechanisms are used that provide continuous air pumping through the exhaust channels. Domestic and foreign manufacturers offer many models of such devices that differ in their design and a number of parameters. A special place in this series is occupied by a radial fan, which is part of modern ventilation systems.
Types and specifications
Radial centrifugal fan is available in several versions. Products are classified according to the following criteria:
- air flow direction;
- the amount of pressure they create;
- direction of rotation.
In the direction of movement, all devices are divided into two large classes:
- double suction units;
- exhaust devices.
According to the pressure, the choice of products is more diverse:
- low level;
- with an average indicator;
- with high pressure.
In the direction of movement of the fan shaft, the devices are with right-handed and left-handed rotation. Units also differ in the place of their installation: intra-channel and remote.
Specifications
Ventilation equipment is characterized by such indicators:
- power consumption from the network;
- type of current and supply voltage;
- indicator of noise operation;
- quality of protection against dust, as well as from thermal and chemical effects;
- temperature Range.
Devices with power up to 5 kW are usually included in single-phase current circuits with a supply voltage of 220 volts. More energy-intensive fans require a three-phase voltage of 380 volts for their power supply.
Radial fans, related to the category of devices with an average pressure of the air flow, are evaluated by their resistance to chemical and other harmful substances. The maximum permissible concentration of dust in the working medium of the duct must not exceed 100 mg / m3. In addition, the presence of components of explosive substances, as well as particles of fibrous or sticky materials, is inadmissible in it.
Principle of Operation and Design
The principle of operation of radial fans is as follows:
- Contaminated air enters the unit inlet.
- Due to the rotation of the wheel-blades, placed in a spiral casing, it is sucked in and moves under the action of centrifugal force.
- Air is collected in the casing of the device and redirected to the outlet.
Structurally, such a device looks like a wheel with blades mounted on a bed with radial bearings and a shaft embedded in it (the latter is closed by a spiral casing). A typical electric motor is used for cycling. On the wheel, in addition to the blades, the rear and front discs, as well as the massive hub, stand out. The shape and number of blades depends on the purpose of a particular model.
Wheels with backward curved blades are installed in cost-effective product models that consume about 20% less power. At the same time, they cope well with current air loads. On the other hand, samples with forward-curved blades are much less noisy, due to the lower engine speed. In addition, these models are characterized by reduced dimensions of the wheel and housing of the entire device.
The difference between axial and radial varieties is manifested in the history of their use by humans for practical needs. The first appeared much earlier and arranged somewhat differently. In products of this type, air masses move around an axis on which fan blades are mounted. The air jets move in the same direction as specified by the rotation of the rotor of the electric motor.
In radial devices, the direction of movement of the input and output flows do not coincide. Inflowing air jets are directed at right angles to the outgoing flow and the axis of the engine.
Radial fan application
Radial-centrifugal models are widely used at production facilities and in everyday life. They are in demand in places where, under operating conditions, it is necessary:
- provide convection of air flows in the ventilation system;
- purify air with high quality;
- manage humidity;
- create a comfortable stay in the building.
The choice of a specific place where these units are used depends on the indicator of the pressure created by it.
Designations in accordance with GOST
There are several options for marking radial (centrifugal) fans, regulated by current standards. All models are distinguished by the magnitude of the generated pressure:
- low level (no more than 1000 Pa);
- medium size (1000-3000 Pa);
- high pressure (3000-12000 Pa).
Possible differences in the marking of the same models are associated with changes to the current standard GOST 5976-90, which determines the rules for the formation of their designations, prescribed for execution by all users.
- The designation of the product is the letter “B”.
- Its type is the “P” or “C” badges (radial or centrifugal).
- The first number in the marking corresponds to the coefficient used to recalculate the total pressure (80, for example).
- The second digital designation is the speed of the unit.
- The last combination of numbers is the outer diameter of the impeller.
The marking of the BP-86-77-6.3 fan is deciphered as follows: the fan is radial with a total pressure coefficient of 0.86. Its speed is 76.5, and the impeller diameter is 630 mm.
Selection rules
When choosing the right type of fan, the main attention is paid to units that consume a minimum of electricity and have high efficiency in normal operating modes. Often, the factor determining the choice of a particular model is the desire of the user to reduce the dimensions of the equipment, which is very important to maintain free space in the kitchen. Having all the information about the characteristics of the working area above an electric or gas stove, you can choose the right model for a number of indicators.
For these purposes, special tables have been developed in which the correspondence of the characteristics of a particular device to such parameters as total pressure "Pv" and productivity "Q" is given. The last indicator depends on the power of the built-in engine and determines the volume of pumped air per unit time.
Main models and manufacturers
The most famous examples of radial fans from the VTs range include products of the VTs 14-46-4.0 brand (1.5 kW / 1000 rpm) manufactured by Rowen from Russia. The presented model is characterized by the following technical parameters:
- Engine power: 1.5 kW.
- Unit productivity: 5400 m3 / hour.
- Mains supply voltage: 380 Volts (three-phase).
- Estimated cost of the product: 25 thousand rubles.
Another model presented on the domestic market is a remote floor fan of the “Mystery MSF-2406” type. It is also very popular with users who are attracted by the following specifications:
- High for its class power rating (45 W).
- The presence of a built-in timer.
- The ability to choose one of 3 speeds.
- Low cost model: 1500 rubles.
Radial fans “Snail” got its name due to the spiral shape of the product.
The most famous representative of this manufacturer is the model “VANVENT BP-16M-160”.
Characteristics:
- The power of the product is 0.55 kW.
- Its performance corresponds to an indicator of 1700 m3 / hour.
- The supply (working) voltage is 230 Volts.
On the market, this model can be purchased for about 8 thousand rubles.
