A New Approach to Analyze the Hydrodynamic Flow in Sealing Aids—PTFE-Lip Seals with Spiral Grooves

Elastomeric lip seals are frequent and reliable machine components. However, their range of application is limited. If these limits are reached, the seals are often replaced by PTFE sleeve-type seals with spiral grooves (PTFE lip seals). The basic geometries and types of grooves have an empirical origin. An exact analysis and with it the knowledge of their function does not exist. This paper presents a project that aims to analyze and optimize the function and design of these grooves. A test rig developed at the Institute of Machine Components at the University of Stuttgart visualizes the flow in PTFE lip seals and between hydrodynamic sealing aids of elastomeric lip seals. The flow is observed and recorded through a glass hollow shaft, which allows an investigation of the behavior in all directions and areas of the lip. This knowledge is essential to develop new geometries and to verify complex fluid dynamic analysis.