Container closure for containers holding liquids where gas can build up internal pressures

摘要

The closure (1) for a vessel has a central holding flange (7) to take a pressure compensation unit (8). The unit (8) has a membrane which is permeable to gas, but impermeable to fluids, and has at least one passage opening (9) for gas passage at the upper side of the closure. The membrane is of a material which contains at least polytetrafluorethlyene (PTFE).