What are the selection principles for plug valves?

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　　A plug valve is a rotary valve that opens or closes by rotating 90 degrees to align or separate the passage in the plug from the passage in the valve body. The principle for selecting a plug valve is mainly determined by where it will be used. ①Used for distributing media and changing the flow direction of the media; its operating temperature is not higher than 300°C, the nominal pressure is PN≤1.6 MPa, and the nominal diameter is not greater than 300 mm. It is recommended to use a multi-port plug valve. ②For the equipment and pipelines in food industries such as milk, juice, and beer production, as well as in pharmaceutical factories, it is recommended to use fixed-cone plug valves made of austenitic stainless steel. ③In oil field extraction, natural gas field extraction, pipeline branch lines, as well as in refining and cleaning equipment, where the nominal pressure class is not higher than Class 300 and the nominal diameter is not greater than 300 mm, oil-sealed conical plug valves are recommended. ④In oil field extraction, natural gas extraction, pipeline branch lines, as well as in refining and cleaning equipment, where the nominal pressure class is not greater than Class 7500, the nominal diameter is not greater than 900 mm, and the operating temperature is not higher than 340°C, oil-sealed conical plug valves are recommended. ⑤In the large-scale chemical industry, in pipelines and equipment containing corrosive media where fast opening or closing speeds are required, polytetrafluoroethylene sleeve-sealed conical plug valves can be used for media based on nitric acid ； For acetic acid-based media, a conical plug valve with a Crl8Ni12Mo2Ti stainless steel insert and a PTFE sleeve seal can be used. ⑥In pipes and equipment for gas, natural gas, and HVAC systems, where the nominal diameter is not greater than 200 mm, plug-type conical stop valves are recommended.