Papermakers' felts and method for dewatering paper and similar webs

Claim 1

A CARRIER FOR SUPPORTING A WET WEB IN A PAPERMAKING MACHINE DURING THE PASSAGE OF SAID WEB THROUGH THE NIP OF A PAIR OF PRESS ROLLS FOR REMOVING WATER FROM THE WEB, COMPRISING AN ENDLESS BELT HAVING A BASE LAYER AND A WEB-CONTACTING CUSHIONING LAYER UNITED IN FACE-TO-FACE RELATIONSHIP WITH SAID BASE LAYER, SAID BASE LAYER BEING PERMEABLE TO WATER AND RELATIVELY INCOMPRESSIBLE UNDER THE PRESSURE EXERTED THEREON BY SAID PRESS ROLLS INCIDENT TO REMOVAL OF WATER FROM SAID WEB AND SAID CUSHIONING LAYER BEING PERMEABLE TO WATER AND RELATIVELY COMPRESSIBLE UNDER SAID PRESSURE, SAID BASE LAYER COMPRISING A MATERIAL HAVING PASSAGEWAYS OF RELATIGELY LARGE SIZE WHICH PROVIDE WITHIN SAID BASE LAYER A VOID VOLUME A SUBSTANTIAL PERCENTAGE OF WHICH REMAINS AVAILABLE FOR THE RECEPTION OF WATER EXPRESSED FROM SAID WEB AND FROM SAID CUSHIONING LAYER UNDER THE PRESSURE EXERTED AT THE NIP OF SAID PRESS ROLLS, SAID CUSHIONING LAYER HAVING PASSAGEWAYS OF RELATIVELY SMALL SIZE WHICH PROVIDE WITHIN SAID CUSHIONNG LAYER A VOID VOLUME A SUBSTANTIAL PERCENTAGE OF WHICH IS READILY DIMINISHED UNDER SAID PRESSURE, AND SAID CUSHIONING LAYER UNDER NO COMPRESSION HAVING A SUBSTANTIALLY SMALLER VOID VOLUME THAN THAT OF SAID BASE LAYER.

Claim 3

A METHOD OF REMOVING WATER FROM A WET WEB IN A PAPERMAKING MACHINE COMPRISING THE STEPS OF DISPOSING A WET WEB ON AN ENDLESS CARRIER HAVING A BASE LAYER AND A CUSHIONING LAYER, THE BASE LAYER BEING PERMEABLE TO WATER AND BEING RELATIVELY INCOMPRESSIBLE, AND HAVING AN INTERNAL VOID VOLUME AT LEAST A SUBSTANTIAL PORTION OF WHICH CONSISTS OF OPENINGS WHICH ARE RELATIVELY LARGE AND WHICH HAVE LITTLE TENDENCY TO RETAIN WATER THEREIN, THE CUSHIONING LAYER BEING PERMEABLE TO WATER AND RELATIVELY COMPRESSIBLE AND HAVING AN INTERNAL VOID VOLUME AT LEAST A SUBSTANTIAL PORTION OF WHICH CONSISTS OF RELATIVELY SMALL OPENINGS, THE CUSHIONING LAYER BEING DISPOSED BETWEEN THE BASE LAYER AND THE WEB; PROGRESSIVELY MOVING THE CARRIER THROUGH AN ENDLESS PATH INCLUDING A PORTION IN WHICH THE CARRIER AND THE WEB THEREON ARE PASSED BETWEEN A PAIR OF PRESS ROLLS WITHONE OF SAID ROLLS INDIRECT CONTACT WITH SAID BASE LAYER, SAID ONE ROLL BEING ADAPTED TO CONTINUOUSLY RECEIVE WATER FROM THE OPENINGS IN SAID BASE LAYER; PRESSING THE PAIR OF PRESS ROLLS TOGETHER WITH THE CARRIER AND WEB THEREBETWEEN WITH PRESSURE SUFFICIENT TO SQUEEZE WATER OUT OF SAID WEB AND INTO SAID CUSHIONING LAYER WHILE COMPRESSING SAID CUSHIONING LAYER TO A THICKNESS NOT SUBSTANTIALLY GREATER THAN ABOUT 50% OF THE UNCOMPRESSED THICKNESS OF SAID CUSHIONING LAYER AND TO AN EXTENT SUFFICIENT TO FORCE WATER TO FLWO FROM SAID WEB AND SAID COMPRESSED CUSHIONING LAYER INTO SAID BASE LAYER, BUT WITH A PRESSURE INSUFFICIENT TO COMPRESS SAID BASE LAYER TO A THICKNESS LESS THAN ABOUT 60% OF THE UNCOMPRESSED THICKNESS OF SAID BASE LAYER AND TO REDUCE THE VOID VOLUME OF SAID RELATIVELY INCOMPRESSIBLE BSE LAYER TO SUCH AN EXTENT AS TO IMPEDE THE FLOW OF WATER THROUGH SAID BASE LAYER TO SAID ONE PRESS ROLL; AND CONTINUOUSLY REMOVING WATER FROM SAID ONE PRESS ROLL.

Claim 4

A METHOD OF REMOVING WATER FROM A WET WEB IN A PAPERMAKING MACHINE COMPRISING THE STEPS OF DISPOSING A WET WEB ON AN ENDLESS CARRIER HAVING A BASE LAYER AND A CUSHIONING LAYER, THE BASE LAYER BEING PERMEABLE TO WATER AND BEING RELATIVELY INCOMPRESSIBLE, AND HAVING AN INTERNAL VOID VOLUME AT LEAST A SUBSTANTIAL PORTION OF WHICH CONSISTS OF OPENINGS WHICH ARE RELATIVELY LARGE AND WHICH HAVE LITTLE TENDENCY TO RETAIN WATER THEREIN, THE CUSHIONING LAYER BEING PERMEABLE TO WATER AND RELATIVELY COMPRESSIBLE AND HAVING AN INTERNAL VOID VOLUME AT LEAST A SUBSTANTIAL PORTION OF WHICH CONSISTS OF RELATIVELY SMALL OPENINGS, THE CUSHIONING LAYER BEING DISPOSED BETWEEN THE BASE LAYER AND THE WEB; PROGRESSIVELY MOVING THE CARRIER THROUGH AN ENDLESS PATH INCLUDING A PORTION IN WHICH THE CARRIER AND THE WEB THEREON ARE PASSED BETWEEN A PAIR OF PRESS ROLLS WITHONE OF SAID ROLLS INDIRECT CONTACT WITH SAID BASE LAYER, SAID ONE ROLL BEING ADAPTED TO CONTINUOUSLY RECEIVE WATER FROM THE OPENINGS IN SAID BASE LAYER; PRESSING THE PAIR OF PRESS ROLLS TOGETHER WITH THE CARRIER AND WEB THEREBETWEEN WITH PRESSURE SUFFICIENT TO SQUEEZE WATER OUT OF SAID WEB AND INTO SAID CUSHIONING LAYER WHILE COMPRESSING SAID CUSHIONING LAYER TO A THICKNESS NOT SUBSTANTIALLY GREATER THAN ABOUT 50% OF THE UNCOMPRESSED THICKNESS OF SAID CUSHIONING LAYER AND TO AN EXTENT SUFFICIENT TO FORCE WATER TO FLWO FROM SAID WEB AND SAID COMPRESSED CUSHIONING LAYER INTO SAID BASE LAYER, BUT WITH A PRESSURE INSUFFICIENT TO COMPRESS SAID BASE LAYER TO A THICKNESS LESS THAN ABOUT 60% OF THE UNCOMPRESSED THICKNESS OF SAID BASE LAYER AND TO REDUCE THE VOID VOLUME OF SAID RELATIVELY INCOMPRESSIBLE BSE LAYER TO SUCH AN EXTENT AS TO IMPEDE THE FLOW OF WATER THROUGH SAID BASE LAYER TO SAID ONE PRESS ROLL; AND CONTINUOUSLY REMOVING WATER FROM SAID ONE PRESS ROLL.