Apparatus for heat treating porous sheet material

Claim 1

APPARATUS FOR HEAT TREATING A CONTINUOUS LENGTH OF SHEET MATERIAL COMPRISING STRUCTURE DEFINING A PRESSURE VESSEL HAVING ENTRANCE AND EXIT OPENING, FIRST AND SECOND RESTRAINING MEANS EACH PROVIDING AN ENDLESS CONVEYING SURFACE FOR ENGAGING RESPECTIVELY, A MAJOR SURFACE OF SAID SHEET MATERIAL AND EFFECTING PASSAGE THEREOF IN SANDWICH FASHION INTO SAID ENTRANCE OPENING THROUGH SAID VESSEL AND OUT SAID EXIT OPENING, SAID FIRST RESTRAINING MEANS COMPRISING A SUBSTANTIALLY IMPERFORATE FLEXIBLE BAND WHICH DIVIDES SAID VESSEL INTO A FIRST GENERALLY FLUID TIGHT CHAMBER THROUGH WHICH THE SHEET MATERIAL PASSES AND A SECOND FLUID TIGHT CHAMBER OPPOSITELY DISPOSED OF THE FIRST, MEANS FOR ESTABLISHING A HEATED FLUID UNDER PRESSURE IN SAID FIRST CHAMBER AND MEANS FOR ESTABLISHING IN SAID SECOND CHAMBER A FLUID UNDER A GREATER PRESSURE THAN IN SAID FIRST CHAMBER, SAID SECOND RESTRAINING MEANS PROVIDING A SUPPORT FOR SAID SHEET MATERIAL AND SAID IMPERFORATE FLEXIBLE BAND WITHIN SAID VESSEL WHEREBY THE PRESSURE DIFFERENTIAL BETWEEN SAID CHAMBERS IMPARTS RESTRAINING FORCES TO THE SHEET MATERIAL PASSING THROUGH SAID VESSEL, SAID SECOND RESTRAINING MEANS FURTHER BEING PERFORATE WHEREBY THE HEATED FLUID OF SAID FIRST CHAMBER COMMUNICATES WITH SAID SHEET MATERIAL IN SAID VESSEL.