Profiling air/steam system for paper-making machines
AssigneeBeloit Corporation
InventorsJames L. Chance, Laurie D. Wicks
Life of this patent
Estimating the term…
Abstract
Method and apparatus are provided for effectively controlling cross-machine moisture profile in a paper web undergoing processing, such as water-removal via a press nip. A compartmentalized system is provided in close proximity across a section of a traveling web undergoing dewatering whereby select size cross-machine compartments, for example, about 6" in width, are selectively provided with steam and/or air so as to control wet and/or dry streaks along the traveling web so that web areas opposite each compartment can be selectively heated for accentuated moistre removal or cooled for retarded water removal. In preferred embodiments, control of the profiling system occurs with the air of moisture sensors and a computer.
Claims7
An apparatus for effective control of cross-machine moisture profile of a paper web in a papermaking machine, in combination:
- fluid permeable pressure roll means supporting a travelling paper web undergoing press nip dewatering;
- a compartmentalized steam box or air box or steam and air box positioned in working relation with said pressure roll means, said box extending in a cross-machine direction substantially across the width of said paper web and having an open front face in fluid communication with said pressure roll means and being positioned in relatively close proximity thereot, said box having a plurality of separate compartments, each in fluid communication with said front face and each having individually controllable steam and air outlets located away from said front face, so as to selectively allow a stream of steam or air in adjustable amount to flood each respective compartment and permeate a discrete, predetermined corresponding area of the paper web over said pressure roll means;
- a single control valve means in fluid communication with each compartment and operatively associated with a source of pressurized steam having a temperature higher than that of the web and means for supplying the pressurized steam and a source of compressed air having a temperature lower than that of the web and means for supplying the compressed air, and said steam and air outlets in each compartment, wherein said single valve means opens one of the means for supplying pressurized steam and the means for supplying compressed air while the other one is being closed to selectively control the proportions of steam and air in each compartment and maintain the total amount of steam or air or mixture of both in each compartment substantially the same;
- means for drawing air through said web and for exhausting the air after the air has partially cooled the web, said air altering the pressing effect of said web while on said pressure roll means by means of cooling the web by adiabatic saturation;
- and
- a water-removal means positioned in working relation with said compartmentalized box for removing water from said paper web.
Dependencies are inferred from the claim text.