The centrifugal fan is a mechanical energy that depends on the input of mechanical energy, increasing the pressure of the gas and delivering the gas side by side. Centrifugal fans are widely used in the ventilation, dust removal and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings. Ventilation and ventilation of boilers and industrial furnaces; Cooling and ventilation in air conditioning equipment and household electrical appliances; Drying and selecting grain; Air - hole wind source and air - cushion vehicle gas and propulsion.
The centrifugal fan is the principle of converting kinetic energy into potential energy, accelerating the gas by using the rotating impeller, then decelerating and changing the flow to convert kinetic energy into potential energy (pressure). In a single-stage centrifugal fan, the gas enters the impeller from the axial direction and the gas flows through the impeller and into the radial direction, then into the diffuser. In the diffuser, the gas changes the direction of flow and the area of the pipe section increases the air speed deceleration, which converts kinetic energy into pressure energy. The pressure increase mainly occurred in the impeller, followed by the diffuser process. In a multi-stage centrifugal fan, the reflux is used to make the air flow into the next blade, resulting in higher pressure.
Working principle of centrifugal fan and the turbine compressor are basically the same, all is due to the low gas flow rate, pressure changes small, generally does not need to consider the change of the gas volume, namely the gas as incompressible fluid handling.
The centrifugal fan can be made into two types: right and left. Facing from the side of the motor: the impeller turns clockwise, which is called the right rotary fan; The impeller turns anticlockwise, called the left rotating fan.
Centrifugal fan is composed of casing, spindle, impeller, bearing drive mechanism and motor.
Case: made of steel plate solid and reliable, can be divided into integral type and semi-open type, semi-open easy to repair.
Impeller: consists of blade, curved front and plate.
Rotor: static balance and dynamic balance should be done to ensure smooth rotation and good performance.
Drive part: main shaft, bearing box, rolling bearing and pulley (or coupling).
The performance characteristics of
Centrifugal fan is a variable flow constant pressure device. When the rotational speed is certain, the pressure of centrifugal fan should be a straight line. Due to internal losses, the actual characteristic curve is curved. The pressure generated by centrifugal fan is influenced by the change of inlet temperature or density. For a given air inflow, the highest inlet temperature (lowest air density) when the lowest pressure. For a given pressure and the flow characteristic curve, there is a power and flow characteristic curve. When the blower run at constant speed for a given flow rate, the required power of inlet temperature, the higher.
The wear of centrifugal fan transmission parts is a common problem of equipment, including the bearings of the fan, the wear of the bearing room and the wear of the axial bearing. For centrifugal fan fault, the traditional maintenance method has welding, thermal spraying, brush, etc., but there are some disadvantages: repair welding high temperature thermal stress can not completely eliminate, easy cause material damage, lead to bend or break parts And brush plating coating thickness restrictions, easy to peel, and two methods above are with metal repair of metal, can't change "hard to hard" cooperate relationship, under the force combination, still can cause package glue roller wear again. The contemporary western countries to solve above problems more polymer composite materials to repair methods, is the blessing of the blue and is widely applied technology system, which has strong adhesion, excellent comprehensive properties such as compressive strength, to remove free machining. No repair welding thermal stress effect, repair, thickness is not restricted, and the product of metal materials do not have rolled back, can absorb the impact of vibration equipment, avoid wear again, in the domestic application of centrifugal fan fault repair also gradually replace the traditional method.