Method for making cellulosic board

Claim 1

IN A METHOD OF FORMING A DENSE BOARD INCLUDING COMPRESSING LOOSE GRANULAR MATERIAL HAVING AIR-FILLED VOIDS BETWEEN THE GRANULES MAKING UP SAID MATERIAL, THE STEPS COMPRISING DEPOSITING SAID MATERIAL ON A GENERALLY PLANE SURFACE IN AN AMOUNT EXCEEDING THAT REQUIRED TO CONSTITUTE SAID BOARD WHILE CONFINING AT LEAST THE LOWERMOST LAYER OF THE RESULTING BED OF SAID MATERIAL AGAINST LATERAL FLOW BEYOND A FIRST PREDETERMINED AREA TO BUILD UP SAID BED OVER SAID AREA TO A HEIGHT SEVERAL TIMES GREATER THAN THE THICKNESS OF SAID BOARD, CONFINING AT LEAST THE UPPERMOST LAYER OF SAID BED AGAINST LATERAL FLOW BEYOND A SECOND PREDETERMINED AREA EXTENDING INSIDE AND SPACED FROM SAID FIRST AREA, AND WHILE SAID BED IS SO CONFINED COMPRESSING SAID BED AGAINST SAID PLANE SURFACE OVER A THIRD AREA INTERMEDIATE IN EXTENT BETWEEN SAID FIRST AND SECOND AREA AND ENCOMPASSING A SUFFICIENT AMOUNT OF SAID MATERIAL TO CONSTITUTE SAID BOARD WHILE DURING SAID COMPRESSION PERMITTING AT LEAST LIMITED DISPLACEMENT OF MATERIAL IN SAID BED OUTSIDE SAID THIRD AREA.