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The operating characteristics of centrifugal fans and axial fans

  • Date:16-04-2020
  • Abstract:

    The main differences between centrifugal fans and axial […]

    The main differences between centrifugal fans and axial fans are:
    1. The centrifugal fan changes the flow direction of the medium in the air duct, while the axial flow fan does not change the flow direction of the medium in the air duct;
    2. The former installation e799bee5baa6e79fa5e98193e58685e5aeb931333339653638 is more complicated
    3. The former motor and fan are generally connected through a shaft, the latter motor is generally in the fan;
    4. The former is often installed at the inlet and outlet of the air conditioning unit, boiler drum, induced draft fan, etc. The latter is often installed in the duct, or in front of the duct outlet.
    In addition, there are diagonal flow (mixed flow) fans, the wind pressure coefficient is higher than the axial flow fan, and the flow coefficient is larger than the centrifugal fan.
    Added a gap between the axial fan and the centrifugal fan. At the same time, it has the characteristics of simple and convenient installation.
    Mixed flow (or axial flush flow) fan combines the characteristics of axial and centrifugal fans, although it looks more like a traditional axial fan.AC Backward Curved Centrifugal Fans Suppliers
    Welding the curved plate blade to the conical steel hub. The flow rate is changed by changing the angle of the blades in the inlet casing upstream of the impeller.
    The casing may have an open entrance, but it is more common that it has a right-angle curved shape, so that the motor can be placed outside the pipe. The drain shell slowly expands to slow the speed of air or gas flow and convert kinetic energy into useful static pressure.
    The role of axial fans and centrifugal fans in mechanical ventilation
    1 Due to the large difference between air temperature and grain temperature, the first ventilation time should be selected during the day to reduce the gap between grain temperature and temperature and reduce the occurrence of condensation. In the future, the ventilation should be done at night as much as possible, because this time the cooling is mainly used. At night, the atmospheric humidity is relatively high and the temperature is low. This reduces the loss of water and makes full use of the low temperature at night, improving the cooling effect. .
    2 In the early stage of ventilation with centrifugal fans, condensation may occur on doors, windows, walls, or even surface grain surface. As long as the fan is stopped, the windows are opened, the axial fan is turned on, and if necessary, the grain surface is turned over to remove the hot and humid air in the silo. Just outside. However, if the axial fan is used for slow ventilation, there will be no condensation, and only the grain temperature of the upper and middle layers will rise slowly. As the ventilation continues, the grain temperature will drop steadily.
    3 When the axial fan is used for slow ventilation, the air flow of the axial fan is small, and the grain is a poor conductor of heat. In the early stage of ventilation, the individual parts are prone to slow ventilation. The grain temperature of the whole warehouse will gradually balance as the ventilation continues.
    4 Grain that is slowly ventilated must be cleaned by a vibrating screen, and the grain that enters the silo must be promptly cleaned of the impurity zone caused by automatic grading, otherwise it is easy to cause uneven ventilation.
    5 Energy consumption calculation: No. 14 warehouse uses an axial fan for a total of 50 days of ventilation, averaging 15 hours a day, sharing 750 hours, the water content has dropped by 0.4%, the grain temperature has dropped by 23.1 degrees, and the unit energy consumption is 0.027kw. h / t. ℃. The No. 28 warehouse has been ventilated for 6 days and shared 126 hours. The average moisture has dropped by 1.0% and the temperature has dropped by an average of 20.3 degrees. The unit energy consumption is 0.038kw.h / t. ℃.
    6 The advantages of slow ventilation with axial fans: good cooling effect; low unit energy consumption, especially important in advocating energy saving today; ventilation timing is easy to master, and condensation is not easy to occur; no separate fan is required, which is convenient and flexible. Disadvantages: Due to the small air volume and long ventilation time; the precipitation effect is not obvious, and high-moisture grains should not be ventilated with axial fans.
    7 The advantages of centrifugal fans: cooling and precipitation effects are obvious, and the ventilation time is short; disadvantages: high unit energy consumption; poor ventilation timing is not easy to condense.
    8 Conclusion: In the ventilation for the purpose of cooling, the axial fan is used for slow, safe, efficient and energy-saving ventilation; the centrifugal fan is used for the ventilation for the purpose of precipitation.


    Hangzhou Airflow Electric Appliances Co.,Ltd



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