Vacuum chamber seal

Claim 1

A SEAL STRUCTURE COMPRISING A PLURALITY OF CHAMBERS, A PARTITION SEPARATING A FIRST OF SAID CHAMBERS FROM A SECOND OF SAID CHAMBERS, AN OPENING IN SAID PARTITION ESTABLISHING ACCESS BETWEEN SAID FIRST AND SECOND CHAMBERS, MEANS FOR SUPPLYING FLUID UNDER PRESSURE INTO SAID FIRST CHAMBER, MEAN FOR EXHAUSTING FLUID FROM SAID SECOND CHAMBER AND SEALING MEANS FOR CLOSING THE OPENING IN SAID PARTITION WHEREBY SAID FIRST AND SECOND CHAMBERS ARE MAINTAINED UNDER A PRESSURE DIFFERENTIAL, SAID SEALING MEANS INCLUDING AN ENDLESS SEALING WEB ENTRAINED ABOUT A PAIR OF ROLLERS JOURNALLED IN SAID FIRST CHAMBER AT OPPOSITE SIDES OF SAID OPENING, SAID ENDLESS SEALING WEB INCLUDING FIRST AND SECOND SEALING RUNS, AND SAID FIRST SEALING RUN BEING PARALLEL TO SAID PARTITION AND IN OVERLYING RELATIONSHIP TO SAID OPENING WHEREBY THE PRESSURE DIFFERENTIAL BETWEEN SAID CHAMBERS URGES SAID FIRST SEALING RUN INTO INTIMATE CONTACT WITH SAID PARTITION, MEANS FOR FEEDING A WEB OF SHEET MATERIAL TOWARD SAID SEALING MEANS ALONG A PREDETERMINED LINEAR PATH, AND SAID PARTITION IS DIPOSED AT AN ANGLE OTHER THAN NORMAL TO SAID PREDETERMINED LINEAR PATH WHEREBY SAID SHEET MATERIAL WEB IS FED THROUGH SAID OPENING WITHOUT ABRUPT ANGULAR CHANGES IN THE CONFIGURATION THEREOF.