High temperature fan cooling method

　　The cooling methods of the high temperature fan spindle are mainly divided into two types: air-cooled and water-cooled. Air-cooled construction is an economical option when designing fans with low temperatures. The cooling effect of water cooling is better than that of air cooling, but the cost is high and the design process is also more diverse.
　　Air-cooled centrifugal fan: the surrounding air is sucked by the wind wheel and enters the cooling wheel, thereby cooling the main shaft. The cooling effect depends on the air volume generated by the wind wheel, and this type of air-cooled structure is commonly used in A-type small high-temperature fans.
　　Water-cooled centrifugal fan: Large-scale high-temperature fans generally use the water-passing structure in the bearing box for cooling, mainly including circulating oil cooling structure and circulating water-cooling structure.
　　Circulating oil cooling structure: the upper part of the bearing box is provided with an oil inlet pipe, and the lower part is provided with an oil return pipe whose diameter is larger than that of the oil inlet pipe. The heat is taken away by the lubricating oil, and is reused after being cooled by the oil cooler of the thin oil station, so that the bearing is always kept at a suitable temperature rise, and the application effect is better. The disadvantage is that the work needs to be completed through a thin oil station, and the cost is also increased. Another problem is to deal with the seal of the bearing housing, because the seal is a pressure seal, otherwise it will leak oil and pollute the environment. Circulating water-cooling structure: A serpentine cooling water pipe is installed in the oil pool of the bearing box to take away the heat of the lubricating oil through the circulating cooling water, thereby completing the cooling. Although the principle is similar to the circulating oil cooling method, it does not require a thin oil station. The sealing effect of the bearing box is not high, and it is a pressureless seal, so it is better than the circulating oil cooling method in terms of application range and cooling effect.