1 due to the large difference between temperature and grain temperature, the first ventilation time should be selected during the day, in order to reduce the gap between the mild temperature of grain, reduce the occurrence of condensation.
After the ventilation as far as possible in the evening, because the ventilation is mainly cooling, at night the atmosphere humidity is relatively high, the temperature is low, so that the reduction of moisture loss, but also make full use of the low temperature at night, improve the cooling effect.
2 with centrifugal fan ventilation in the early stage may appear doors and windows, wall condensation, and even surface grain surface slight condensation, as long as Stop the fan, open the window, turn on the axial fan, if necessary, flip the grain surface, will be in the warehouse of the hot and humid air to exclude the outside of the warehouse can be.
And the use of axial fan for slow ventilation will not appear condensation phenomenon, will only appear the middle-class grain temperature slowly rise, with the continued ventilation of the grain temperature will steadily decline.
3 with axial fan for slow ventilation, due to the axial fan air volume is small, in addition to the grain is a bad conductor of heat, ventilation in the early stage prone to individual parts of the slow ventilation, with the continued ventilation of the whole warehouse will gradually balance.
4 The grain for slow ventilation must be cleaned by vibrating sieve, and the grain entering into the warehouse must clean the impurity area caused by automatic grading in time, otherwise it is easy to cause local ventilation uneven.
5 Energy consumption calculation: warehouse 14th with axial fan accumulated ventilation for 50 days, an average of 15 hours per day, a total of 750 hours, water fell by an average of 0.4%, grain temperature dropped by an average of 23.1 degrees, the unit energy consumption is: 0.027kw.h/t.℃.
Warehouse 28th accumulated Ventilation for 6 days, a total of 126 hours, water fell by an average of 1%, the temperature of the average drop of 20.3 degrees, the unit energy consumption is: 0.038kw.h/t.℃.
6 with axial fan to carry out slow ventilation advantages: good cooling effect, low unit energy consumption, in the promotion of energy saving today is particularly important, ventilation timing is easy to master, not easy to appear condensation, do not have to be equipped with fans alone, convenient and flexible.
Disadvantages: Because of the small air volume, long ventilation time, precipitation effect is not obvious, high moisture grain should not be ventilated with axial fan.
7 Advantages of centrifugal fan: cooling, precipitation effect is obvious, ventilation time is short; disadvantages: high energy consumption per unit; Ventilation timing is not easy to appear condensation.
8 Conclusion: In the ventilation for the purpose of cooling, the axial flow fan is used for safe, efficient and energy-saving slow ventilation, and the centrifugal fan is applied in the ventilation for the purpose of precipitation.
