Valve for venting fluid

Claim 1

A HERMETICALLY SEALED FLUID VALVE CLOSURE ASSEMBLY FOR A CONTAINER HAVING AN ORIFICE, COMPRISING A RIGID CENTRALLY-APERTURED SUPPORTING MEMBER, MEANS FOR SEALING THE EDGE OF SAID SUPPORTING MEMBER TO THE WALL OF SAID CONTAINER AT ITS ORIFICE, A CENTRALLY-APERTURED SEALING DISC COMPOSED OF A RESILIENT SEALING MATERIAL HAVING ONE OF ITS SURFACES IN SEALING ENGAGEMENT WITH SAID SUPPORTING MEMBER, A VALVE MEMBER HAVING A CUP-FORM VALVE HEAD THE EDGE THEREOF ENGAGING THE OTHER SURFACE OF SAID SEALING DISC THROUGHOUT ITS PERIPHERY, AND MEANS PROVIDING AXIAL CLAMPING FORCE OF PREDETERMINED MAGNITUDE FOR CLAMPING SAID SEALING DISC TIGHTLY BETWEEN THE EDGE OF SAID VALVE HEAD AND SAID SUPPORTING MEMBER TO FORM A SEAL BETWEEN SAID VALVE HEAD AND SAID SEALING DISC, THE SURFACE OF SAID SUPPORTING MEMBER ENGAGING SAID SEALING DISC BEING PROVIDED WITH A GAP OF LIMITED PERIPHERAL EXTENT SUPREIMPOSED OVER A LIMITED PORTION OF THE PERIPHERY OF THE EDGE OF SAID VALVE HEAD, SEALING FORCE AGAINST THE EDGE OF SAID VALVE HEAD BEING APPLIED AT THE AREA OF SAID GAP ONLY BY FORCES WITHIN SAID SEALING DISC RESISTING DISPLACEMENT OF THE PORTION THEREOF AT THE LOCATION OF SAID GAP, THE ARRANGEMENT BEING SUCH THAT SAID CONTAINER ERMAINS HERMETICALLY SEALED UNDER NORMAL PRESSURE CONDITIONS, AND WHEREBY INCREASED PRESSURE WITHIN SAID CONTAINER OF A PREDETERMINED MAGNITUDE CAUSES THE PORTION OF SAID SEALING DISC OVER SAID GAP TO BE SUFFICIENTLY DISPLACED AS TO BREAK SAID SEAL TEMPORARILY AND TO PERMIT FLUID TO ESCAPE FROM SAID CONTAINER.