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Axial fan exhaust hood principle and centrifugal fan function

Release Time：2021-07-20

Axial fan design local exhaust hood should pay attention to the principle.
1. The local exhaust hood should be surrounded or close to the harmful passive as much as possible, so that the harmful passive is limited to a small local space, and the suction range should be reduced as much as possible to facilitate capture and control.
2. The direction of the suction airflow of the exhaust hood should be as consistent as possible with the direction of the polluted airflow.
3. The contaminated inhalation airflow is not allowed to pass through the human breathing zone, and the position and range of activities of the operator should be fully considered during the design.
4. The exhaust hood should strive for simple structure, low cost, and easy installation and maintenance.
5. The configuration of the local exhaust axial flow fan cover should be coordinated with the production process, and strive not to affect the process operation.
6. It is necessary to avoid and reduce the influence of interference airflow, through-hall wind, and air supply airflow on the inhalation airflow as much as possible.
Due to the large difference between the temperature and the grain temperature, the first ventilation time should be selected during the day to reduce the difference between the grain temperature and the temperature and reduce the occurrence of condensation. Later ventilation should be carried out at night as far as possible, because this ventilation is mainly based on cooling, and the atmospheric humidity is relatively high and the temperature is low at night, thus reducing the water loss, making full use of the low temperature at night and improving the cooling effect.
At the initial stage of ventilation with off-axial flow fan core fan, doors and windows, wall condensation and even slight condensation on the surface grain surface may occur. As long as the fan is stopped, the window is opened, the axial flow fan is turned on, and the grain surface is turned over if necessary, the humid and hot air in the warehouse can be removed from the warehouse. However, if the axial flow fan is used for slow ventilation, condensation will not occur and only the middle and upper grain temperature will slowly rise, as the ventilation continues, the grain temperature will drop steadily.
When the axial flow fan is used for slow ventilation, due to the small air volume of the axial flow fan and the poor conductor of heat, the slow ventilation of individual parts is easy to occur at the initial stage of ventilation, and the temperature of the whole warehouse grain will gradually balance with the continuous ventilation of the axial flow fan.
The grain for slow ventilation must be cleaned by the vibrating screen, and the grain entering the warehouse must be cleaned in time to clean the impurity area caused by automatic classification, otherwise it is easy to cause uneven local ventilation.
The advantages of slow ventilation with axial flow fan: good cooling effect, low unit energy consumption, especially important in today's advocacy of energy saving, easy to grasp the timing of ventilation, not easy to appear condensation, no separate fan, convenient and flexible, disadvantages: due to small air volume, long ventilation time, precipitation effect is not obvious, high moisture grain should not be ventilated with axial flow fan.
Shandong Xingheng Environmental Technology Group Co., Ltd. is located in Luquantun Development Zone, Dezhou, Shandong, the hometown of FRP in China. The company has Grade II qualification for fire protection facilities engineering, Grade II qualification for construction mechanical and electrical installation engineering, Grade II qualification for environmental protection engineering, and safety production license. It is the first in the industry to pass ISO9001 quality management system certification, ISO14001 environmental management system certification, OHSAS18001 occupational health management system certification, and an axial fan invention patent, A fan utility model patent, environmental assessment, safety assessment, three simultaneous and other procedures are complete.