How to choose a fan case

1、 Key points for product selection
1. The selected control parameters for the fan case include air volume, total pressure, efficiency, noise, and motor power. There are centrifugal and axial flow types.
2. The ventilation fan is equipped with a fan box, which is beneficial for noise reduction.
When selecting a ventilation fan, consideration should be given to the air leakage loss and calculation error of the pipeline system, as well as the negative deviation of the actual air volume and air pressure of the ventilation fan. Generally, a safety factor of 1.05-1.1 air volume and 1.10-1.15 air pressure is adopted. But it should not be too large to prevent the ventilation fan from operating in a low efficiency zone for a long time.
4. Pay attention to the matching relationship between the resistance characteristics of the pipeline network and the characteristics of the ventilation fan. To ensure stable operation of the ventilation system, the fan should be operated near its maximum efficiency point, with its operating point located to the right of the peak point of total pressure in the performance curve (i.e. on the high air volume side, and generally at 80% of the peak point of total pressure).
2、 Key points of construction and installation
1. The ventilation fan should be arranged on the floor or platform as much as possible for maintenance and repair; When the motor power of the centrifugal fan is less than or equal to 75kW, a valve only for starting may not be installed. When selecting a centrifugal boiler induced draft fan for discharging high-temperature flue gas or air, a starting valve should be installed to prevent motor overload during cold operation.
2. The installation pedestal (foundation) of the ventilation fan should have sufficient strength, stability, and durability, and the vibration of the pedestal should meet the following requirements:
1) The natural frequency of the basic device shall not exceed one-third of the speed of the motor and ventilation fan;
2) The difference between the vibration speed during the operation of the ventilation fan and the vibration speed when the ventilation fan is stationary should be greater than three times.
3. Flexible joints should be installed between the inlet and outlet of the ventilation fan and the air duct. The inlet and outlet ducts and other devices should be separately supported and firmly supported by foundations or other building components. The casing should not bear the weight of other components.
When installing ventilation fans on building components, vibration isolation measures should be taken.
3、 Characteristics of fan case
1. There are many varieties and specifications, and a wide range of air volume and pressure options.
2. Equipped with multi-directional air inlet and outlet, the unit can be installed in a suspended or floor standing manner, which is convenient for installation and conducive to engineering design.
3. The unit has low noise, low vibration, high air volume, and small size.
4. Adopting a fully metal detachable frame and internal insulation sound-absorbing board, it can be disassembled and installed on site with flexible placement.
5. The high-temperature resistant structural plate, motor, and transmission components are all installed at the outer end of the fan case. Can emit high-temperature flue gas above 280 ℃ and operate continuously for more than 100 minutes.