Vacuum pump is a kind of mechanical equipment widely used in industrial production. In the transformer industry, it is a key equipment used to vacuum the drying tank to improve the drying quality of the transformer body. Filled polytetrafluoroethylene piston ring is mainly used in grain, medical, laboratory, military industry, plastic processing and other industries. In these industries, compressor cylinder is generally within the range of 30-700mm.
On the other hand, considering that the mechanical strength and hardness of the filled polytetrafluoroethylene material are far lower than that of the metal material, using it in the cylinder that is too large or too small may cause eccentric wear or wear too fast, which can not meet the requirements of service life. In addition, if the air pressure difference between the inlet and exhaust of the cylinder is too large, the PTFE piston ring will be deformed and the sealing performance will be greatly reduced. This paper mainly describes the application of lower oil-free vacuum pump in filling polytetrafluoroethylene piston ring.
In order to improve the product quality of tetrafluoro piston ring, ensure the normal operation of compressor equipment, and improve the quality control awareness of tetrafluoro piston ring manufacturers.
In chemical production, oil-free vacuum pump is widely used to raise the pressure of various feed gas to meet the requirements of production process. Since the end of 1970s, some domestic manufacturers and scientific research institutions have started to study the oil-free vacuum pump, with two main purposes: first, to solve the oil-bearing problem of process gas, for example, in the synthetic ammonia reaction, the high oil-bearing of circulating gas will cause catalyst poisoning and reduce the output; second, to improve the operation cycle of compressor, because the original cast iron ring or copper ring is under the action of alternating stress Fatigue fracture often occurs with heavy maintenance work and high consumption of vulnerable parts.
Performance difference between filled piston ring and metal ring:
The material ratio of tetrafluorocarbon ring is: F4: bronze powder: glass fiber: Graphite = 100:40:20:10, which is different from the main characteristics of metal ring: the material expansion coefficient is large, so the thermal expansion gap should be considered reasonably, generally larger than the metal ring; the material strength is low, so the piston ring section is larger than the metal ring; the material friction coefficient is small, the material is soft, and the relative wear resistance is relatively good Poor, the specific pressure should be minimized as far as possible; the material rigidity is small, the piston ring is easy to fit with the cylinder surface under the action of gas back pressure, the sealing effect is good, and the number of piston rings can be correspondingly reduced; the thermal conductivity of the material is lower than that of the metal, so enough attention should be paid in the design and use.
With the continuous expansion of vacuum technology in various fields of application, the demand for oil-free vacuum pump is increasing. In order to solve the problems of oil leakage of shaft seal and the performance and quality of materials and vacuum pump oil, to ensure the stable performance and reliable operation of no oil pump at high speed and high temperature, and to further improve the ability of vacuum pump to remove water vapor. The manufacturer of EVP free vacuum pump indicated that the application of oil-free vacuum pump in filling Teflon piston ring is to save lubricating oil and improve the performance of vacuum pump. The modification scheme of filling Teflon plastic piston ring instead of cast iron piston ring of the original machine was adopted to realize oil-free lubrication of the air cylinder of vacuum pump.