Research On Reciprocating Piston Seal Technology

A new form working condition in low pressure, low speed and dry-friction, which is seldomapplied in reciprocating seal. Since the relative research about this kind of seal is relatively few, soit is still lack of the mature theoretical and reliable experimental data. According to the actualworking condition and requirement of the piston pump in the space station control system, itredesign the sealed structure so as to the life of pump can be increased under meeting the sealedrequirement.When the piston pump works in the space station, it doesn’t require relatively high for the sealperformance at the points of the piston. But it requires highly for the using life of the seal systemconsidering the difficulty of equipment replacement. In this article, the structure of the sealing ringis designed as a forming of double triangle combination with rectangular groove which is usuallyused in projects according to the research and experiment. The structure of double trianglecombination is compact, simple installation; wear resistance, extrusion and two-side sealed;especially suitable for light, small diameter and reciprocating dynamic seal.The three-dimensional model is designed based on the designed structure of sealing device.The deformation and the load of the sealing ring in different compressing rate and different airpressure is analyzed by MSC.Patran and Nastran finite element simulation software, and based onthe analysis results, the distribution nephogram and the maximal change table of the Von Misesstress when compressing rate and air pressure changed are plotted, as well as the contact pressurechart in the different compressing rate and different air pressure. Among the range of0to0.25MPa,as air pressure increasing, the change of the maximal Von Mises Stress about the sealing O-ringisn’t severely and the change on the double triangle is opposite, the peak value appears in the borderof the main sealing area. The chart indicates that the contact stress in the main sealing districtchanges correspondingly severely and the position also changes. Moreover, it always satisfies thesealing need.Some experiments are processed for comparing the friction of the different material ofmatching vice with different air pressure and different compression ratio. Meanwhile the change trend of friction is also analyzed. The experiment indicates that the friction increases as thecompression ratio increase. The influence of the air pressure on the friction is few among the rangeof0to0.2MPa. Under the condition of the same compression ratio and air pressure, the friction ofthe sealing ring matching zirconia ceramic bush is slightly less than matching326L stainless steelwith spraying the DLC thin films.At last, the comparing experiments on the life of the pump with various matching vice materialare done and find out the relative feasible matching vice materials based on the reasonable andsatisfied finite element analysis.