In terms of pump material and structure, if it is a non-corrosive liquid, carbon steel is used for pressure-resistant parts below 370°C, and 5% or 13% chromium steel is used above 370°C; for parts with low strength , cast iron can be used below 230 ℃. When the thermal expansion coefficients of the components of the components are not the same, the tight fitting parts will become loose, and the gap of the rotating sealing parts will become smaller and cause accidents. The pump casing with complex shape may cause accidents due to irregular expansion and deformation, so generally All take vertical divisions. When the temperature changes, the bolt tightening force of the pressure-resistant pump casing will change, and leakage will occur from the joint surface of the pump casing, so the joint surface must be used. If you use the sealing flat gasket of the horizontally split pump casing, when the bolt tightening force is loosened and the leakage starts, the gasket will be blown out, and there is a danger of high temperature liquid blowing out, so this gasket is not suitable for high temperature use.