Development And Performance Testing Of Ultra-high Pressure Non-metallic Seals

In the actual production of the oil field in our country,the design and manufacturing technology of ultra-high pressure throttle valve and its sealing system was always controlled by foreign researchers.The domestic individual,research institute or manufacturer has less systematic research on it.The usage amount of throttle valve and its vulnerable parts increased year by year.And it has affected the production safety and the economic efficiency seriously.Therefore,to develop the sealing system of the throttle valve which belong to our country is imminent.The development of sealing technology at home and abroad,common sealing materials,sealing numerical simulation technology and sealing technology at low temperature are investigated in this study.Then the working condition of the sealing ring in the throttle valve is set as the starting point.Combined with the structure of throttle valve,the sealing rings which have good static and dynamic sealing performance under the working conditions of 105MPa ultra-high pressure,strong corrosive medium and-46? low temperature are designed.They are evaluated as "comparable to imported sealed components" when applied to the production siteThis study is carried out and reaped in the following aspects:(1)The material of the sealing ring is studied and chosen:PTFE and its modified materials are selected as the base metal of the sealing ring.The tensile and compression tests of PTFE and modified PTFE with 10%carbon fiber were carried out,and the stress-strain relationship of two materials was obtained.(2)Choose the suitable types of sealing ring according to the structure of the throttle valve:Analysis of throttle valve structure,it is concluded that there are five parts of the throttle valve that need to be designed the sealing ring.Among them,the surface to surface static seal and axial dynamic seal are included The O seal ring is chosen as the sealing ring of surface to surface static seal,and the lip sealing ring is used as the sealing ring of the axial gap dynamic seal.(3)The structure design of the sealing ring:The wire diameter and internal diameter of the O seal ring and the size of seal groove which matched with the the O seal ring is determined according to the size of the end face.The sealing performance of O seal ring at normal temperature and low temperature under 105MPa pressure is checked through numerical simulation.The structure of lip seal ring is designed combined with the size of seal coupling surface.The contact stress and effective contact width of the lip sealing ring are analyzed under different magnitude of interference through numerical simulation.The most suitable magnitude of interference is selected;Performance of the lip sealing ring at normal temperature and low temperature under 105MPa pressure is checked.(4)The manufacture of the sealing ring sample is finished and the performance test is carried out in the same working condition:To verify the correctness and reliability of the design.A pressure testing device which can test the sealing performance of all the sealing rings is designed in this study.Through the experiment and the feedback of field application,it is proved that the sealing system designed in this study can withstand the pressure of 105MPa and meet the working condition of the oil field.