China Pumping Solutions Leader
Hot oil pump material and seal
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..
The shaft seal of the thermal oil pump used to use gland packing, and now a mechanical seal device for high temperature has been developed. Since the wear of the sealing end face increases sharply with the increase of temperature, the heat resistance of the “O” and “V”-shaped gaskets is also a problem, so most of them take cooling measures for the shaft seal device, and the cooling method is to use the operating temperature The cooling liquid that does not evaporate at the bottom is used for external flushing or self-flushing. At the same time, a cooler is set in the flushing pipeline to cool the flushing liquid to 80-120 °C and then inject it into the mechanical sealing device. Cooling with self-flushing tends to condense high-viscosity media in the cooler during pump shutdown, so the cooler must be equipped with a steam line for heating. In addition, when the pump is stopped for warming up or self-flushing without a cooler, it is necessary to pay attention that the temperature of the shaft seal device cannot be too high. Once the heat resistance temperature of the mechanical seal is exceeded, even if the pump has stopped, it must be discharged from the After the check valve of the pipeline, the flushing liquid is drawn out for flushing.
