Sealing Performances Research on PTFE Rotating Seal under Deep-Sea Environment

Xuepeng Cao*, 1, Cuihong Zhang1, Bo Zou2, Lei Li3
1 College of Engineering Machinery, Chang'an University, Xi'an 710064, China
2 SANY Group Co., Ltd., Changsha 410100, China
3 Baoji Oilfield Machinery Co., Ltd., 721015, USA

© 2015 Cao et al

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the College of Engineering Machinery, Chang'an University, Xi'an 710064, China; Tel: +8602982334496; Fax: +8602982334496; E-mail:


In order to improve the environmental adaptability and sealing performance of the rotating seal, the principles and failure mechanisms of the rotating seal in ambient pressure in deep-sea is researched. It is proposed that the excessive friction caused by the ambient pressure and the magnitude of interference is the main reason for rotating seal failure. To reduce friction effect, a combined lip seal is designed, whose structure consists of a rotating seal made of polytetrafluoroethylene (PTFE) and an O-shaped fastening ring. The finite element analysis results indicate that the contact pressure in sealing surface increases with the growing magnitude of interference, but decreases when it exceeds the value 0.65mm. A suitable range (0.5×10 m ~0.6×10m) for the magnitude of interference is concluded for this combined seal. Finally, the designed PTFE rotating seal is tested in a deep-sea imitating hull, and the experimental results show that the seal is able to work reliably without leaking for more than 10 hours in the ambient pressure less than 30MPa, and verifies the design of the rotating seal is rational, which displays that the seal is available for the special requirement of deep-sea environment in short periods.

Keywords: Contact pressure, deep-sea environment, deep-sea imitating hull test, magnitude of interference, rotating seal.