Leakage Measurements of PTFE Sealing Rings, Sleeves, and Stoppers for Glass Taper Joints

摘要

Laboratory work with traditional taper jointed glassware is facing problems of joint freezing and, more seriously, of joint sealing (References 1-5). Joint grease can often not be used because it is not inert. PTFE joint seals are more inert and prevent joints from freezing. But there is a widespread misconception that PTFE is too expensive and too hard for a good seal of the rough glass joint surface. Unfortunately, little quantitative leak-age measurement data has been published on the sealing performance of different shaped PTFE taper joint seals (References 1, 6). Frank (1) found that PTFE joint sleeves have no additional sealing effect. We found, however, that the shape and performance of the existing PTFE joint seals is very different and some of them offer an amazingly good and economic seal. Here we will examine the relation between the shape and the sealing performance of PTFE joint sleeves, stoppers and sealing rings (References 5, 6).