Method for maximizing water removal in a press nip
AssigneeFort James Corporation
InventorsSteven L. Edwards, Robert J. Marinack, Jeffrey Charles McDowell, Gary L. Worry
Life of this patent
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Abstract
The present invention is a method for maximizing water removal from an absorbent web in a press nip. The present invention uses a pressing unit with a pressure profile that maximizes water removal in the press section or on the Yankee dryer of a paper machine. The pressure profile of the pressing unit according to the present invention has a very steep pressure drop at and/or following the exit of a pressure distribution curve in order to maximize water removal by minimizing rewet of the web. The improved pressure profile according to the present invention results in increased water removal and/or improved line speed.
Claims58
A method of making an absorbent paper sheet product comprising:
- depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric;
- and
- contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip between said foraminous endless fabric and an impervious member, wherein said nascent web directly contacts said impervious member, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m2.
The method of 1, wherein said pressing unit includes a hydraulic engagement member and said hydraulic engagement member is shaped and positioned to substantially align the separation of said foraminous endless fabric from said web and the separation of said foraminous endless fabric from said endless pressing blanket.
A method of making an absorbent paper sheet product comprising:
- depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric;
- and
- contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m2, and wherein said moving endless blanket engaged with said pressing unit forms said nip with a Yankee drying cylinder.
A method of making an absorbent paper sheet product comprising:
- depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric,
- contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m2,
- transferring said web to a Yankee drying cylinder;
- and
- creping said web from said Yankee drying cylinder,
- wherein said moving endless pressing blanket engaged with said pressing unit is configured to form said nip with said Yankee drying cylinder.
A method of making an absorbent paper sheet product comprising:
- depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric;
- contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip between said foraminous endless fabric and an impervious member, wherein said nascent web directly contacts said impervious member, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m2,
- transferring said web to a Yankee drying cylinder;
- and
- creping said web from said Yankee drying cylinders.
A method of making an absorbent paper sheet product comprising:
- depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric;
- contacting said moving foraminous endless fabric bearing said deposited nascent web with a shoe press thereby forming a nip between said shoe press and a Yankee drying cylinder, said shoe press being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m;
- disengaging said web from said foraminous endless fabric in said nip onto said Yankee drying cylinder;
- and
- drying said web on said Yankee drying cylinder;
- and
- creping said web from said Yankee drying cylinder.
Dependencies are inferred from the claim text.