Continuous pulping process

Claim 1

A METHOD FOR THE PRODUCTION OF PULP FROM WOOD BY AN ALKALINE PROCESS IN A GENERALLY VERTICAL CONTINUOUS DIGESTER AT SUPERATMOSPHERIC PRESSURE AND ELEVATED TEMPERATURES, WHICH COMPRISES FEEDING BLACK LIQUIOR AND THE WOOD IN THE FORM OF CHIPS TO AN ENTRY POINT ADJACENT THE TOP OF THE DIGESTER AND CAUSING THE CHIPS TO MOVE DOWNWARDLY THROUGH THE DIGESTER TO A DISCHARGE POINT ADAJACENT THE BOTTOM THEREOF, THE WOOD MOVING UNDER GRAVITY THROUGH A PRELIMINARY TREATMENT ZONE, A COOKING ZONE AND A DIFFUSION-DISPLACEMENT ZONE IN THE DIGESTER; THE WOOD CHIPS IN THE PRELIMINARY TREATMENT zONE BEING IN CONTACT WITH BLACK LIQUOR, THE BLACK LIQUOR PASSING THROUGH SAID PRELIMINARY TREATMENT ZONE IN A DIRECTION CO-CURRENT TO THAT OF THE WOOD; INTRODUCING AN ALKALINE COOKING LIQUOR, CONTAINING ACTIVE CHEMICAL, AT AN ELEVATED TEMPERATURE AND PRESSURE INTO THE DIGESTER AT A POINT WHERE THE WOOD IS SUBSTANTIALLY COOKED; THE COOKING LIQUOR PASSING THROUGH THE COOKING ZONE IN A DIRECTION COUNTERCURRENT TO THE MOVEMENT OF WOOD THERETHROUGH, RETAINING AT LEAST 90% OF THE ACTIVE CHEMICAL CONTAINED IN THE COOKING LIQUOR IN THE DIGESTER WITH THE COOKED WOOD AND THEREFORE AVAILABLE FOR USE IN THE COOKING OF MORE WOOD; INTRODUCING WASHING LIQUID INTO THE DIGESTER AT A POINT BETWEEN THE POINT OF ENTRY OF THE COOKING LIQUOR AND THE POINT OF DISCHARGE OF THE COOKED WOOD FROM THE DIGESTER, THE WASHING LIQUID PASSING SERIALLY THROUGH THE DIFFUSION-DISPLACEMENT ZONE AND THE COOKING ZONE IN A DIRECTION COUNTERCURRENT TO THE MOVEMENT OF WOOD THERETHOUGH, THE MOVEMENT OF WOOD THROUGH THE COOKING ZONE AND DIFFUSION-DISPLACEMENT ZONE BEING EFFECTED WITHOUT MECHANICAL DISINTEGRATION OR AGITATION IN THE SAID ZONES; DISCHARGING BLACK LIQUOR FROM THE DIGESTER BETWEEN THE PRELIMINARY ZONE AND THE COOKING ZONE, AND DISCHARGING COOKED WOOD SUBSTANTIALY FREE OF ACTIVE CHEMICAL FROM THE DIGESTER AT SAID DISCHARGE POINT

Claim 2

A METHOD FOR THE PRODUCTION OF PULP FROM WOOD BY AN ALKALINE PROCESS IN A GENERALLY VERTICAL CONTINUOUS DIGESTER AT SUPERATMOSPHERIC PRESSURE AND ELEVATED TEMPERATURES, WHICH COMPRISES FEEDING BLACK LIQUIOR AND THE WOOD IN THE FORM OF CHIPS TO AN ENTRY POINT ADJACENT THE TOP OF THE DIGESTER AND CAUSING THE CHIPS TO MOVE DOWNWARDLY THROUGH THE DIGESTER TO A DISCHARGE POINT ADAJACENT THE BOTTOM THEREOF, THE WOOD MOVING UNDER GRAVITY THROUGH A PRELIMINARY TREATMENT ZONE, A COOKING ZONE AND A DIFFUSION-DISPLACEMENT ZONE IN THE DIGESTER; THE WOOD CHIPS IN THE PRELIMINARY TREATMENT zONE BEING IN CONTACT WITH BLACK LIQUOR, THE BLACK LIQUOR PASSING THROUGH SAID PRELIMINARY TREATMENT ZONE IN A DIRECTION CO-CURRENT TO THAT OF THE WOOD; INTRODUCING AN ALKALINE COOKING LIQUOR, CONTAINING ACTIVE CHEMICAL, AT AN ELEVATED TEMPERATURE AND PRESSURE INTO THE DIGESTER AT A POINT WHERE THE WOOD IS SUBSTANTIALLY COOKED; THE COOKING LIQUOR PASSING THROUGH THE COOKING ZONE IN A DIRECTION COUNTERCURRENT TO THE MOVEMENT OF WOOD THERETHROUGH, RETAINING AT LEAST 90% OF THE ACTIVE CHEMICAL CONTAINED IN THE COOKING LIQUOR IN THE DIGESTER WITH THE COOKED WOOD AND THEREFORE AVAILABLE FOR USE IN THE COOKING OF MORE WOOD; INTRODUCING WASHING LIQUID INTO THE DIGESTER AT A POINT BETWEEN THE POINT OF ENTRY OF THE COOKING LIQUOR AND THE POINT OF DISCHARGE OF THE COOKED WOOD FROM THE DIGESTER, THE WASHING LIQUID PASSING SERIALLY THROUGH THE DIFFUSION-DISPLACEMENT ZONE AND THE COOKING ZONE IN A DIRECTION COUNTERCURRENT TO THE MOVEMENT OF WOOD THERETHOUGH, THE MOVEMENT OF WOOD THROUGH THE COOKING ZONE AND DIFFUSION-DISPLACEMENT ZONE BEING EFFECTED WITHOUT MECHANICAL DISINTEGRATION OR AGITATION IN THE SAID ZONES; DISCHARGING BLACK LIQUOR FROM THE DIGESTER BETWEEN THE PRELIMINARY ZONE AND THE COOKING ZONE, AND DISCHARGING COOKED WOOD SUBSTANTIALY FREE OF ACTIVE CHEMICAL FROM THE DIGESTER AT SAID DISCHARGE POINT