It is made of hard polyvinyl chloride (PVC) or hard polypropylene (PP) board, which is processed by hot pressing and welded. The fan belongs to the medium and low fan category, and has the advantages of high efficiency, low power consumption, corrosion resistance, beautiful appearance, low noise, strong fastness, and no need for frequent maintenance. It is widely used in the ventilation and ventilation of chemical industry, metallurgy, electronics, instrumentation, electroplating, chemical fiber textile, medicine, scientific research, environmental protection, restaurants and public places. Eliminate indispensable equipment containing acids, alkalis and toxic and harmful gases.