Tubular PTFE seal with internal ribs - for vacuum sealing laboratory glassware esp. stirrer shapes through clinical adaptors

摘要

A seal for surrounding a rotating shaft comprises an oversize tubular body with >=1 integral internal annular rib for contact with the shaft and >=1 integral external rib for supporting the seal in a housing, the ribs being at offset levels along the tubular body. The seal is made of material having sufficient flexibility to deform elastically when a shaft of slightly greater dia. than the internal seal rib bore is inserted through the seal. Used for sealing shafts or thermometer pockets, etc. entering laboratory glassware via conventional conical adaptors, esp. for assemblies to be maintained under vacuum. Pref. the seal has two internal ribs located below the mouth of the seal so that some (silicon oil) lubricant/coolant can be retained above the upper seal. The seal is made of PTFE or a fluorocarbon copolymer. The seal may be located by a complementary external push fit cap which engages the external flange. Alt. twin external ribs locate and align the seal within a hollow adaptor.