In recent years, various new types of grain storage equipment have emerged one after another. However, the axial flow fan has always been favored by the majority of storage units for its large air volume and low energy consumption, and has been widely used in tall and large warehouses. Now combine the use of axial flow fans in grain storage to discuss the specific use functions.
No.1
Winnowing
Due to the different proportions of grains and light impurities, mobile axial fans are used for cleaning. The history of winnowing and removing impurities can be said to have a long history, with many methods and methods. Just need to set up an axial fan at the conveyor unloading place. The air volume is adjusted by the distance between the moving axial fan and the material, which can effectively achieve the purpose of cleaning debris. The advantages of this method are: labor-saving, labor-saving, energy-saving, and does not affect the continuity of the operation. The disadvantage is that the dust is relatively large.
(The axial flow fan is removed from impurities and gradually withdrawn from the stage of history)
No.2
Balance the temperature of the chamber and reduce heat and moisture transfer
After the new grain is stored in the warehouse, the grain surface should be leveled in time, and the temperature measuring cable should be buried in the normal storage stage. Before the entire warehouse is sealed, it is very important to ventilate for two reasons:
1. Grain layer temperature difference: tall and large bungalows have large storage capacity and long storage time. The temperature of batches of grain is not the same, and there is a temperature difference.
2. Grain dampness: Although the same batch of grain in the warehouse is the same warehouse and the same variety, the origin, storage time, moisture, impurities, etc. are different. In addition, the storage time is long, and there is heat and humidity in the grain pile in the warehouse. The accumulation phenomenon, these will bring certain hidden dangers to the storage work.
Generally speaking, the ventilation requirements and technical parameters of this period should meet the requirements of the "Grain and Oil Storage Technical Specifications", and it is best to use a grain cooler for initial cooling. In order to save costs, if low-temperature storage is not required, an axial fan can also be used for ventilation, which is simple and convenient, but the requirements for ventilation time and atmospheric parameters are stricter.
During this period, through short-term ventilation, two goals can be achieved: one is to balance the warehouse temperature and humidity, which can effectively prevent local condensation and heating, and make a good start for the next step of storage; the second is to find the grain in the pile in time After the problem is ventilated, high temperature points can be found in time through microcomputer detection, and timely inspection and treatment are carried out to avoid hidden dangers.
No.3
Reduce the temperature and fumigation of the warehouse in summer
1. Reduce warehouse temperature in summer
As the temperature rises in summer, the grain temperature will also rise slowly. Most of the heat exchange is carried out through the roof, doors and windows, especially the roof. When there is no condition to improve the roof of the silo, you can use the low temperature in summer night (relatively speaking) to turn on the axial fan at the right time, which is divided into two steps: one is to turn on the roof fan to discharge the accumulated heat on the roof. The second is to open the fan and working door in the warehouse to discharge the accumulated heat in the warehouse. Practice has proved that this method can reduce the warehouse temperature by about 5°C and delay the increase in grain temperature.
2. Fumigation and ventilation
After the fumigation is over, the toxic gas in the warehouse should be removed in time, and combined with natural ventilation, the deflation time can be shortened to facilitate the inspection work of the staff.
No.4
Reduce warehouse temperature and grain temperature in winter
The axial flow fan can completely replace the centrifugal fan when the grain conditions are normal during the cooling work in winter to achieve the purpose of reducing the temperature of the grain pile. According to the atmospheric conditions of the geographical location of the reservoir area (for example: December: 0-10°C; January: -5-5°C; February -2-15°C). In general, ventilation will be adopted in October. Mechanical ventilation is divided into three steps: (1) The initial cold starts in late October, and the temperature of the grain is lowered to below 20 ℃ through ventilation for about a week. (2) In the first ten days of December, take advantage of the low night temperature to continuously ventilate, and strive to reduce the grain temperature below 15°C. (3) In early February, use a reasonable time and work for a period of time to strengthen and stabilize the ventilation effect. The warehouse can be sealed in early March.
During this period of ventilation, try to use the low temperature at night for intermittent ventilation to achieve the purpose of energy saving and efficiency. Let the dry and cold air fully exchange with the hot and humid air of the grain pile. After each ventilation, one set of axial flow fans is turned off, and the other set is running to extract the hot and humid air from the space in the warehouse to prevent external condensation.
No.5
The advantages and disadvantages of axial fans
Compared with the effect of centrifugal fans, the effects of the wide application of axial fans in tall and large warehouses are as follows: 1. Easy installation and flexible operation. 2. Low energy consumption, under the premise of achieving the same effect, the energy saving effect is considerable. 3. After the grain temperature drops, the grain temperature basically does not rebound, and the rise is slow. Especially the use of intermittent ventilation, the effect is more obvious. 4. Easy to combine with other methods of ventilation.
Nevertheless, the axial flow fan also has its shortcomings. First, the ventilation time is long and the wind pressure is low. Especially in the south, the shortcomings are very obvious in the limited effective ventilation days. Second: Relatively speaking, its air volume and pressure are small, and it cannot handle large-area heat in time.
