HTSW bellows seal single seat control valve is a top guide structure regulating valve, the valve has the advantages of compact structure, fluid channel was streamlined S, the pressure drop, flow is large, wide adjustable range. The valve cover with bellows seal structure, can completely eliminate the possibility of the process medium leakage from the stem clearance, which is one of the significant characteristics of bellows seal valves. As the bellows element itself can be anti ageing deformation and outstanding, this valve completely overcomes the packing seal valves are packing aging and sensitive temperature difference. Secondly, using the corrugated pipe -- packing a double seal structure, safety and reliability better, therefore, it is widely used in highly toxic, the automatic control system of strong corrosive, radioactive and other rare special medium. The spool oriented area, good vibration resistance, equipped with multi spring diaphragm actuator, which has the advantages of compact structure, large output force.