Introduction to the Structure and Principle of PTFE Packing
　　PTFE packing seal is achieved by installing the PTFE packing into the packing gland and compressing it against the shaft surface using the packing gland cover. Since the shaft surface is somewhat rough, it only partially contacts the packing, leaving other areas uncontacted, thus forming numerous labyrinths. When pressurized media passes through the shaft surface, the media is throttled multiple times, achieving sealing through this "labyrinth effect." The contact and friction between the PTFE packing and the shaft surface resemble a sliding bearing, requiring sufficient liquid lubrication to ensure a certain lifespan of the seal, known as the "bearing effect." Therefore, a good PTFE packing seal is a combination of both the labyrinth effect and the bearing effect. 
 　　PTFE packing exerts a compressive force on the shaft by tightening the gland bolts. As the PTFE packing is an elastoplastic material, when axially compressed, friction causes the compressive force to gradually decrease along the axial direction, while the generated radial compressive force presses the packing tightly against the shaft surface to prevent media leakage. The distribution of radial compressive force decreases sharply from the outer end (gland) to the inner end before leveling off, while the media pressure distribution decreases gradually from the inner end to the outer end. When the media pressure at the outer end is zero, leakage is minimal; if it is greater than zero, leakage occurs. 
 　　With the continuous emergence of new materials, the structural forms of PTFE Packing Introduction and UsesPTFE packing have also undergone significant changes, which will undoubtedly promote the wider application of PTFE packing seals. Materials used for PTFE packing should possess the following characteristics: certain elasticity and plasticity. When the PTFE packing is axially compressed, it should generate a large radial compressive force to achieve sealing; when the machine and shaft vibrate or the shaft has runout and eccentricity, it should have a certain compensation ability (followability); chemical stability. It should not be corroded or swollen by the media, nor should it contaminate the media; impermeability. Most fibers are somewhat permeable to media, so the packing structure must be dense. Therefore, during the manufacturing of PTFE packing, it is often necessary to impregnate and fill various lubricants and fillers; good self-lubrication, low friction coefficient, and wear resistance; temperature resistance. It should withstand certain temperatures when friction generates heat; easy disassembly; simple manufacturing and low cost.