There are many kinds of ventilation duct equipment in Jinan. Today, I would like to tell you about two of them, one is axial flow fan, the other is centrifugal fan. These two kinds of machinery are commonly used in the industrial field or engineering, and they are widely used. Today, let's take a look at the difference between these two kinds of fans.
The role of axial fan and centrifugal fan in mechanical ventilation
Due to the large difference between temperature and grain temperature, the first ventilation time should be selected in the daytime to reduce the difference between grain temperature and temperature and reduce the occurrence of condensation. The future ventilation should be carried out in the evening as far as possible, because the ventilation is mainly to reduce the temperature. The air humidity is relatively high and the temperature is low in the evening. In this way, the water loss is reduced, and the low temperature at night is fully utilized to improve the cooling effect.
2. In the early stage of ventilation with centrifugal fan, there may be dew condensation on the doors and windows and walls, and even slight condensation on the surface grain surface. As long as the fan is stopped, the window is opened, the axial fan is turned on, and the hot and humid air in the bin can be removed from the warehouse if necessary. However, if the axial-flow fan is used for slow speed ventilation, there will be no condensation, and only the temperature of the middle and upper layers will rise slowly, and the grain temperature will decrease steadily with the continuous ventilation.
3. When the axial fan is used for slow speed ventilation, because the air volume of the axial fan is small and the grain is a poor conductor of heat, the ventilation of individual parts is slow in the initial stage of ventilation, and the temperature of grain in the whole warehouse will gradually balance with the continuous ventilation.
4. The grain with slow ventilation must be cleaned by vibrating screen, and the grain entering the warehouse must be cleaned in time to the impurity area caused by automatic classification, otherwise it is easy to cause uneven local ventilation.
Jinan ventilation duct
5 energy consumption calculation: the axial-flow fan used in No.14 warehouse has accumulated 50 days of ventilation, with an average of 15 hours per day and 750 hours of common use. The average water content and grain temperature decreased by 0.4% and 23.1 ℃ respectively, and the unit energy consumption was 0.027kw.h/t. ℃. The results show that the total ventilation time of No.28 warehouse is 6 days and 126 hours. The moisture content and temperature are reduced by 1.0% and 20.3 ℃ respectively. The unit energy consumption is 0.038 kW · H / T. ℃.
The advantages of slow speed ventilation with axial flow fan are: good cooling effect; low unit energy consumption, which is particularly important in today's advocating energy conservation; the ventilation opportunity is easy to grasp, and condensation is not easy to occur; there is no need to equip the fan separately, which is convenient and flexible. Disadvantages: due to the small air volume and long ventilation time, the effect of precipitation is not obvious, so the axial flow fan is not suitable for ventilation of high moisture grain.
Advantages of centrifugal fan: obvious cooling and precipitation effect, short ventilation time; disadvantages: high unit energy consumption; poor ventilation timing, prone to condensation.
Conclusion: the axial fan is safe, convenient and energy-saving in the ventilation for cooling, and the centrifugal fan is used in the ventilation for precipitation.
In fact, the differences between the two kinds of ventilation duct equipment are obvious in terms of operation principle and structure. The reason why we can easily distinguish these two kinds of fans is that they have a big difference in appearance, but their strengths are also different, and they can complement each other more easily. 上一篇：安装厨房排烟罩如何才能保证空气的质量？