Composite material butterfly valves, made from specially formulated load-bearing materials. From the initial development of this material, emphasis was placed on its quality ratio, corrosion resistance, strength, and cost factors. As a result, these valves exhibit superior corrosion resistance compared to traditional cast iron and steel plate butterfly valves, with a lower quality ratio and a minimal opening pressure of only 0.0003 MPa, far surpassing traditional valves. Compared to stainless steel butterfly valves, their low cost is a decisive advantage. Composite material butterfly valves are the ideal replacement for traditional valves. The valve seat employs a double flange structure, where the lower flange serves to connect and fix the valve, and the upper flange is responsible for sealing, stopping water, and drainage. The circular butterfly valve fixed flange conforms to standards and is compatible with steel flanges available in the market, while the rectangular butterfly valve fixed flange is a non-standard flange.