(1) Lip filler
Due to the soft lip of the lip fille慢是r, it will expand laterally and tig冷他htly adhere to the retainin妹的g wall under the action of店請 the medium pressure. This expa農區nded filler can be used in compresse明東d fillers, and relatively hard materi去訊als cannot be used. The機視 disadvantage of lip p車商acking is that its seal北事ing effect is only unidirecti費老onal. Most of the lip packing u靜費sed for valve stems i亮如s made of pure PTFE or filled PTFE. 鐵但But some are made of fiber-r女可einforced rubber or 年農leather. Mainly used in hydraulics. Mo身慢st of the lip packing used as the麗友 valve stem is made into a V-shape. Th金都is is both easy to install and easy to 可靜expand.

(2) Extruded packing
The name of the extruded packin門飛g applies to packing 多北such as O-rings. After the packing i可好s installed, its side is squeezed, and女照 the lateral preload f為購orce is maintained by th和影e elastic deformation of the 吃物material. When the medium enter放短s the packing cavity fro南間m the bottom, the packing moves to the 不又gap between the valve stem and the sup光道port seat, thereby bl是到ocking the leakage path. When th輛小e pressure in the packing cav靜司ity drops again, the packing res樂小umes its original shape.

(3) Thrust packing
The thrust packing consists of a 的可packing ring or a gasket 拿訊installed between the valve cover and t坐草he valve stem shoulder. The valve 報費stem can move freely in th討房e axial direction relative to th近愛e packing ring. The initial valve行雜 stem seal can be provided by an auxil的來iary shaft seal such as錯爸 a shrinking packing, or 錯兵a spring, which forces t靜和he valve stem shoulder against子影 the thrust packing, and th讀朋e subsequent medium pressure can大紙 force the valve stem shoul笑街der to be tighter Contact with fil懂些ler.

(4) Sealing of diaphragm valve st白樂em
The diaphragm valve stem i到喝s sealed by a flexib自在le and pressure-bearing valve c行機over, which connects 暗能the valve stem and the clo章多sing member. This kind of話體 seal can prevent any medium from le林月aking to the atmosphere t中門hrough the valve stem as long as 車錢the diaphragm does no服內t fail. The material of 白靜the diaphragm varies a日科ccording to the purpose o影術f the valve. It can be stainless st店錢eel, plastic or rubber, 草森etc.