Capillary dewatering method and apparatus
AssigneeKimberly-Clark Tissue Company
InventorsStrong C. Chuang, Kenneth Kaufman, Robert H. Schiesser
Life of this patent
Estimating the term…
Abstract
Disclosed is a method for reducing the moisture content of a paper web in a papermaking process from in the range of 10% to 32% dry to the range of 33% to 50% dry wherein the embryonic web is supported on a knuckled through drier fabric and lightly pressed between the knuckled through drier fabric and a capillary membrane of a capillary dewatering roll. The capillary membrane has capillary pores therethrough which have a substantially straight through, non-tortuous path with a pore aspect ratio of from about 2 to about 20. A vacuum is drawn within the capillary dewatering roll which is not greater than the negative capillary suction pressure of the capillary pores.
Claims20
A method of reducing the moisture content of a fiber web in a webmaking process, comprising the steps of:
- (a) supporting the web on an air-permeable fabric;
- (b) lightly pressing the web between the air-permeable fabric and a capillary membrane of a capillary dewatering roll that has pores defined therein that are configured to induce a negative capillary suction pressure, wherein the web is transported about a peripheral segment of the capillary dewatering roll;
- and
- (c) drawing a vacuum within the capillary dewatering roll, the vacuum being not greater than the negative capillary suction pressure of the capillary pores.
A method of removing a portion of the liquid contained in a continuous wet porous web in a papermaking process without substantial overall compaction of the web, comprising steps of, with steps (b) and (c)in no particular order:
- (a) delivering a jet of stock from a head box to a forming fabric to form an embryonic paper web;
- (b) vacuum dewatering the embryonic web such that the embryonic web is in the range of from about 6% to about 32% dry;
- (c) transferring the web from the forming fabric to an open, knuckled transfer fabric;
- (d) lightly pressing the web between the open, knuckled transfer fabric and a capillary membrane of a rotating capillary dewatering roll, the capillary membrane having capillary pores therethrough which have a substantially straight through, non-tortuous path, the capillary pores having a pore aspect ratio of from about 2 to about 20, wherein the web is transported about a peripheral segment of the capillary dewatering roll;
- (e) drawing a vacuum within the capillary dewatering roll that is not greater than the negative capillary suction pressure of the capillary pores.
A method of removing water from a wet porous web in a papermaking process without substantial overall compaction of the web, comprising steps of:
- (a) positioning the web on a capillary membrane of a rotating capillary dewatering roll that has capillary pores therethrough which have a substantially straight through, non-tortuous path, the capillary pores having a pore aspect ratio of from about 2 to about 20, wherein the web is transported about a peripheral segment of the capillary dewatering roll;
- (b) separating the web from the capillary membrane;
- and
- (c) spraying the capillary membrane with a cleansing fluid to wash the surface of the capillary membrane and to flush any particulates trapped within the capillary pores through the straight through, non-tortuous capillary pores to the inside of the nonsectored rotating capillary dewatering roll.
Dependencies are inferred from the claim text.