Opening and closing parts (valve) driven by the stem, do along the seat (sealing surface) axis linear motion of the valve lift called the shutoff valve. Shut-off valve is generally by the driver (hand wheel), stem, valve, valve cover, valve main parts (closed parts) and packing equipment and other components. Handwheel and the valve stem is connected, and with the valve stem drive, so the valve seat along the axial direction of the reciprocating motion, so that the pipe is turned on or off. Shut-off valve which is widely used, mainly for higher pressure and diameter smaller occasions, generally produce only to DN400 (NPS16), larger diameter specifications apply only to the specific pipe. For example, a large oxygen piping, valves due to the presence of other easy to produce static friction fire, so the use of large-diameter stainless steel valve. Shutoff valve stem generally do rotating movement at the top of the hand wheel fixed to the stem. When the hand wheel clockwise, threaded lower stem, the valve sealing surface in close contact with the valve seat sealing surface standard, globe valve reaches the closed state; when the hand wheel counter-clockwise rotation, rotating the valve stem threads, valve sealing surface and seat sealing surface disengaged, globe valve open. Butterfly valve and flange contact surface small butterfly manufacturers, especially butterfly bolt hole DN50 another big, how easy to strict security screws how it does not leak proof lid on Hemmi professionals introduce you to:? 1. If you are 2. If it is, then go corrosive media valve specifications, with PTFE gasket, tighten the bolts; water, then go with EPDM gasket, tighten the bolts, using the symmetrical method or approach the star method torque Use the symmetry method or star method torque; 3. If you are already in contact with the flange surface butterfly valve leak, repairs carried out, it must first clean up the sealing surface, if the funds under the conditions permit, you can buy These flat sealant, such as Loctite 518; domestic back days, can match the new have similar; you can also use expanded PTFE gaskets. Telescopic butterfly, butterfly Wan Jiang, England electromechanical provided by City Electrical Equipment Co., Ltd. of England. England City Electrical Equipment Co., Ltd. (www.gdyinglun.com) strong, credible, hydraulic machinery and components industry in Dongguan, Guangdong has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead England into the brilliant electromechanical and you work for a better future!