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Ventilation and Fumigation of Grain Steel Silo
Design of Ventilation and Fumigation System for Grain Steel Silo
Ventilation and fumigation are the most basic condition and important means to ensure the safe storage of grain steel silo. The steel silo has characteristic of deep grain mass, big resistance and gradient changes of moisture content and temperature of inside silo, which has a certain effect on the grain metabolism. So it is not easy to be penetrated grain mass by gas as fumigation, not easy to dissipate heat and humidity, with big resistance of ventilation airflow, etc. At the same time, because large storage capacity and great input & output conveying capacity of the silo, it may cause dust explosion easily.
Fumigation is to prevent the damages of pests, rats or birds to grain and mildew caused by pests or microbes to ensure the stability of grain storage. Therefore, the reasonable design of grain steel silo for ventilation and fumigation can not only ensure grain safety, but also achieve better energy-saving effect and higher economic benefits, which has advantageously guaranteed the safety management of grain storage.
Ventilation Mode of Grain Steel Silo
Ventilation can be divided into two types: natural ventilation and mechanical ventilation.
Ventilation system is the must-have storage facilities for each grain steel silo, which can promote air exchange inside grain mass and keep the balance of grain temperature and moisture content to prevent mildew. Its functions are to create low temperature environment, improve grain storage performance, prevent the transfer of moisture content, cool and disperse dampness, expel off-putting smell inside grain mass, disperse the air after fumigation, suppress occurrence and spread of pests and mildew, and prevent dust and explosion. The axial-flow fan on the top of steel silo can expel hot and humid air within the surface of grain in a timely manner, which not only speeds up directional flow of air in silo, but also prevents condensation phenomenon aroused by temperature difference between inside and outside of the silo.
At the same time, it can adjust the top space temperature and dissipate hot and humid in the upper space and the surface of the silo to prevent grain on the upper layer and the surface from affection by high temperature.
The ventilation system of grain steel silo needs special design. The ventilation system is generally consisted of three parts: air blower, air channel and galvanized air deflector. Soft connection is used to connect air blower and air channel to reduce noise. Two types of deflector: earth cage type and tablet embedded type. Air channel can be installed inside or outside silo.
Fumigation Mode of Grain Steel Silo
Circulation fumigation system is based on the theory of grain storage, aerodynamic circulation theory, the theory of chemical control, the use of microcomputer control technology, a system function in strict accordance with China GB/T17913-1999 standard manufacturing, security, performance, ideal insecticidal effect high degree of high-tech storage and environmentally friendly products.
Application and Development of Grain Silo in China
The application and development of grain steel silo technology in China started late, which has experienced four periods:
- Trial period of application (1979-1981): small steel silo mainly as temporary storage silo and transit silo.
- Introduction period of applied technology (1982-1984): galvanized corrugated sheets fabricated steel silo was introduced from the United States (fabricated steel silo for short), which belongs to agricultural steel silo. Afterwards, Canadian commercial grain steel silo was introduced by the Light Industry Department of China, which’s mainly as raw material processing silo and transit silo in port.
- Digestion, absorption and upgrade period of applied technology (1983-early 1990s). Since 1983, China has introduced Lipp technology and SM special steel sheet-reeling equipment and manufactured Lipp steel silo (spiral steel silo for short). On the basis of absorbing and digesting foreign silo technology, construction technology of steel silo has gotten significant innovation and development.
- Development period (1995- ): During this period, construction and application of steel silo has made great development in China, mass production and installation of steel silo have been in full swing, the strength, safety and performance of steel silo have greatly improved，so a large number of silo products have exported abroad, reflecting international level in construction technology of steel silo currently. In China, after only 20 years of practice, grain steel silo is now widely used in each link of storage and transportation.