Manufacturing method of composite filled polytetrafluoroethylene guide ring piston ring
Engineering Elements, Components; Thermal Insulation; Manufacture and Application Technology of Fastener Devices
Technical field:
The invention relates to improving the wear resistance and service life of an oil-free lubricating compressor, especially a guide ring piston ring of a nitrogen compressor.
At present, domestic oil-free lubricating compressors mainly use filled PTFE guide rings and piston rings, that is, PTFE as the main body, filled with bronze powder, molybdenum disulfide, silica, graphite and glass fiber, etc., after pressing Integral or split guide ring piston ring. This guide ring piston ring has a short service life, especially for nitrogen compressors, its service life is even shorter. In general, the service life of the pilot ring piston ring used in nitrogen compressors is one-fourth of that used in oxygen compressors. Due to the short service life of the guide ring piston ring, it not only increases the material cost, but also frequently stops due to the replacement of the guide ring piston ring, which increases the non-production maintenance time and economic loss, and affects the product quality and output.
The purpose of the present invention is to improve the service life of the oil-free lubrication compressor guide ring piston ring, which requires a modified design of the original filled polytetrachloroethylene material, and requires the new material to have high surface hardness, high compressive strength and compressive deformation resistance. Small, its filler should have a large thermal conductivity and a small friction coefficient. This purpose is to realize the formula of the new material through the following design scheme and molding process. The main body is polytetrafluoroethylene, and the filler is mainly composed of high-molecular polymer p-hydroxybenzoic acid polyester, supplemented by glass fiber, polyphenylene, etc. , which changed the filling system based on inorganic materials in the past. The specific plan is
The above ingredients should be mixed evenly and formed by hot pressing (temperature 360-380℃, pressure>58MPa).
From the wear mechanism of the polymer, it can be seen that increasing the surface hardness can slow down the adhesive wear; hot pressing can reduce the nucleation of microcracks and microscopic voids, which can avoid delamination wear; the most important thing for the polymer is the abrasive wear. friction transfer and transfer wear, the former is related to frictional heat generation, the latter for PTFE, the formation of a highly oriented cold transfer film (ie lubricating film) on the dual surface, both require the filler to have a large thermal conductivity . It was developed abroad in the 1970s, and the domestic production of trial products was not long ago. The parabens, in addition to the thermal conductivity of 3-5 larger than PTFE, also has excellent wear resistance and self-lubrication, and the hardness is higher than that of PTFE. Teflon is much larger, so it is an ideal bulk filler. The glass fiber in the filler increases the mechanical strength of the guide ring piston ring. The self-lubricating property of polystyrene is better than that of molybdenum disulfide and graphite, and a small amount of polystyrene is added to further improve its self-lubricating property.
The test results of the present invention and the original filled PTFE guide ring piston ring sample are as follows
The invention has passed the actual examination of production and operation, and the service life of the piston ring of the original filled polytetrafluoroethylene guide ring is increased by more than 6 times.
Rights request
1. The oil-free lubricating compressor compound type filled PTFE guide ring piston ring is mainly made of PTFE, filled with some important substances, and then pressed into shape, characterized in that the filler is made of high molecular organic matter Polyester based on para-hydroxybenzoic acid, supplemented by composite systems such as glass fiber and polyphenylene.
2 . The composite filling system according to claim 1 , characterized in that 60% of polytetrafluoroethylene, 25% of polyester paraben, 10% of glass fiber, and 5% of polyphenylene are the composite filling system according to claim 1 . 3 .
full text abstract
In the present invention, polytetrafluoroethylene is used as the main body, and the main material of the filler is high-molecular polymer p-hydroxybenzoic acid polyester, supplemented by glass fiber, polyphenylene and other pressing-molded guide rings and piston rings. In terms of mass percentage, the composite filling system is 60% of polytetrafluoroethylene, 25% of p-hydroxybenzoic acid polyester, 10% of glass fiber, and 5% of polyphenylene. The invention is used in various oil-free lubricating compressors, especially in nitrogen compressors, and can increase the service life by more than 6 times.