board forming press and method of making board substitutes

Claim 1

A HOT PRESS FOR FABRICATING ARTIFICIAL BOARDS FROM PREFORMED MATS OF BOARD-MAKING CONSTITUENTS CAPABLE OF BEING CONSOLIDATED UNDER HEAT AND PRESSURE WITH ATTENDANT RELEASE OF STEAM COMPRISING AN UPRIGHT PRESS FRAME, A PLURALITY OF SEPARATE PLATENS EACH COMPRISING MEANS PROVIDING AN UPPER PLANE SURFACE AND A LOWER PLANE, STEAM-IMPERVIOUS SURFACE FIXEDLY HELD IN SPACED-APART, PARALLEL RELATION TO EACH OTHER WITH OPEN SPACES THEREBETWEEN FOR THE PASSAGE OF A HEATING MEDIUM, A PLURALITY OF SEPARATE CAUL PLATES HAVING STEAM-IMPERVIOUS SURFACES AND EACH OF A SIZE TO SUPPORT A PREFORMED MAT OF BOARDMAKING CONSTITUENTS AND TO REST UPON ONE OF SAID UPPER PLATEN SURFACES ENTRIELY WITHIN THE BOUNDARIES THEREOF, SAID FRAME BEING ADAPTED FOR HOLDING A STACK OF ALTERNATELY SUPERIMPOSED PLATENS AND ACUL PLATES WITH MATS OF BOARD-MAKING CONSTITUENTS THEREBETWEEN IN PROGRESSIVE STAGES OF CONSOLIDATION, STEAM-IMPERVIOUS SURFACES OF SAID PLATENS AND CAUL PLATES BEING DIRECTLY IN CONTACT WITH THE BOARD-MAKING CONSTITUENTS AND STEAM ESCAPE FROM SAID CONSTITUENTS BEING PERMITTED ONLY AT THE EDGES OF THE