PTFE oil seal material advantages
(1) Chemical stability: Almost all chemical resistance, strong acid, strong alkali or strong oxidizing agent and organic solvent have no effect on it.
(2) Thermal stability: The cracking temperature is above 400 °C. Therefore, polytetrafluoroethylene can work normally in the temperature range of -200 ° C to 300 ° C.
(3) Friction reduction: The friction coefficient of PTFE material is extremely low, only 0.02, which is 1/40 of rubber.
(4) Self-lubricity: The surface of the PTFE material has outstanding self-lubricating properties, and almost all viscous substances cannot adhere to its surface.
PTFE oil seal filling modification
Pure polytetrafluoroethylene is not wear-resistant, and to make it practical, it must be filled with a modification treatment. We use two methods: one is inorganic filler modification, and glass fiber, carbon fiber, graphite, molybdenum disulfide, etc. are added to the polytetrafluoroethylene. The other is organic material filling modification, adding polyphenylene sulfide, polyphenylene sulfide, etc. to polytetrafluoroethylene (suitable for water purification, food, medicine sealing). Through the filling modification, the wear resistance of the polytetrafluoroethylene is improved by 2000 times, and the steel property and the thermal conductivity are increased, so that the oil seal reaches a high life requirement.
PTFE sealing principle
The PTFE oil seal lip is pulled into a trumpet shape during processing. Since the Teflon has a memory shrinking ability after being drawn, the friction heat generated during the work causes the lip to shrink continuously, so no spring help is needed. It will hold tightly on the shaft, so that it does not have a gap with the shaft surface, and it can compensate for the wear.
PTFE oil seal advantages
Polytetrafluoroethylene (PTFE) oil seals have the following advantages over rubber oil seals:
(1). The rubber oil seal adopts a spring-pressed sharp lip, and the contact surface width with the shaft is only 0.3-0.5mm. The PTFE oil seal adopts a spring-free wide lip power structure, and the shaft contact surface width is 5-7mm, so that one can maintain one. Sufficient oil film, and insensitive to the eccentricity of the shaft, can still work normally under the condition of radial runout of 0.4mm.
(2). The inner wall of the Teflon oil seal is engraved with a thread groove opposite to the shaft turning. When the shaft rotates, an inward thrust is generated to prevent fluid outflow. This thrust is very high, so that the pressure of 1.0MPa (single lip), 3MPa (double lip) fluid can be sealed, and the rubber oil seal is only 0.03MPa.
(3). Teflon oil seals offer excellent friction resistance and are particularly suitable for use in oil-free or low-oil applications. Even with re-activation after long-term shutdown, they have immediate low-friction properties.
(4). PTFE oil seals are especially suitable for high speed rotary applications up to 30m/s
(5). The PTFE oil seal can be made without leakage.