Advantages and disadvantages of axial flow fan and centrifugal fan
The centrifugal fan test meets the regulations. The centrifugal fan adopts a unique design, built-in heat-resistant motor, and is equipped with a motor refrigeration system. It can operate at a temperature of 300 ° C for 100 minutes, and it can continue to operate for 20 times without damage. Zhongtou. Widely used in excellent industrial buildings and electric ovens. Underground parking spaces, tunnel construction and other places.
1. Because the average temperature and grain temperature are very far apart, the first ventilation time should be selected in broad daylight to reduce the difference between grain temperature and average temperature and ease the generation of condensation. The subsequent ventilation should be carried out at night as much as possible. Since this ventilation is dominated by cooling, the relative humidity of the air environment at night is high and the temperature is low, which not only reduces the water consumption, but also flexibly uses the ultra-low temperature at night to improve the cooling. actual effect.
2. In the early stage of ventilation with a centrifugal fan, there may be condensation on windows, doors, walls, and even mild condensation on the grain surface. If the centrifugal fan is stopped, the window is opened, the axial flow fan is turned on, and the grain surface is rolled if necessary. The cold and humid gas inside can be removed from the warehouse. However, the deceleration ventilation with the axial flow fan is not easy to cause condensation, and the grain temperature of the upper class always rises slowly, and the grain temperature will decrease steadily with the re-development of ventilation. Strictly control the gap between the blade and the outer cylinder of the fan, making it far smaller than the national standard requirements and improving the operation efficiency.
3. When the axial flow fan is used for deceleration ventilation, because the exhaust air volume of the axial flow fan is small (the number of motor poles is too high, the speed of the motor spindle is slow, and the air volume is small;) In addition, the grain is quasi-steady state of heat, and it is very easy to appear in the early stage of ventilation. In some places, the ventilation is slow, and the temperature of the full warehouse will gradually balance with the re-opening of ventilation.
4. Grain for deceleration ventilation (which involves a reducer ventilation and heat dissipation device) must be removed by vibrating screen, and the grain entering the warehouse must be immediately cleaned of the residue area caused by automatic grade classification, otherwise it will easily lead to partial ventilation failure. uniform.
5. Energy consumption calculation: No. 14 warehouse uses axial flow fan for a total of 50 days, with an average of 15 hours a day and 750 hours at the same time, the average moisture value has dropped by 0.4%, the average grain temperature has dropped by 23.1 degrees, and the energy consumption of the enterprise is: 0.027 kw.h/t.℃. Warehouse No. 28 was ventilated for a total of 6 days and used for 126 hours. The average moisture content decreased by 1.0%, the average temperature decreased by 20.3 degrees, and the energy consumption of the enterprise was: 0.038kw.h/t.℃.
6. Advantages of decelerating ventilation with axial flow fans: the actual effect of cooling is excellent; the energy consumption of enterprises is low, which is very important in today's environmental protection and energy saving; handy.
Disadvantages: Because the exhaust air volume is small, the ventilation time is long; the actual effect of rainfall is not significant, and high-moisture grains are not suitable for ventilation with axial flow fans.
7. Advantages of centrifugal fans: the actual effect of cooling and rainfall is remarkable, and the ventilation time is short; defects: the energy consumption of enterprises is high; the ventilation opportunities are not well grasped, and condensation may occur.
8. Basis: In the ventilation for the purpose of cooling, use the axial flow fan to carry out safe, high-efficiency, environmental protection and energy-saving deceleration ventilation; in the ventilation for the purpose of rainfall, use the centrifugal fan.
Ventilation system is a building environment control technology that controls the spread and harm of air pollutants by means of ventilation dilution or ventilation exclusion, and realizes the quality assurance of indoor and outdoor air environment. It is to realize the function of ventilation, including a complete set of devices including air inlets, air outlets, air supply ducts, fans, filters, control systems and other auxiliary equipment.