System for modifying the moisture profile of a paper web
AssigneeJames River Paper Company, Inc.
InventorJohn R. Joiner
Life of this patent
Estimating the term…
Abstract
A paper web in a paper machine including a yankee dryer is dried and the moisture profile thereof controlled by arraying a plurality of gas burners in a cross-machine direction within the hood of the yankee dryer to direct heat toward different incremental width portions of the paper web. The burners are independently controlled by a scanning moisture gauge.
Claims15
Apparatus comprising, in combination:
- a rotatable heated dryer drum having an outer cylindrical surface for transporting a paper web in the machine direction of a paper making machine and drying said paper web during transport upon rotation of said dryer drum;
- a hood defining an interior at least partially encompassing said rotatable heated dryer drum;
- heater means operatively associated with said hood and said drum to modify the moisture profile of the paper web as it is transported by said drum through said hood interior, said heater means comprising a plurality of independently operable gas burners arrayed in the cross-machine direction adjacent to said drum within said hood interior and burner control means for independently controlling each of said burners to control the heat emitted thereby, said burners directing heat to respective different incremental width portions of the paper web being transported by the dryer drum through the hood interior to modify the moisture profile of the paper web;
- and
- moisture profile sensing means for sensing the moisture profile of the paper web after said paper web has been removed from the outer cylindrical surface of said heated dryer drum, said moisture profile sensing means and said burner control means being in operative association to separately control operation of said burners and vary the heat emitted thereby responsive to the moisture profile sensed by said moisture profile sensing means.
A method of modifying the moisture profile of a paper web produced on a paper making machine including a rotatable dryer drum having an outer cylindrical surface and a dryer hood partially encompassing said dryer drum and having a hood interior, said method comprising the steps of:
- positioning a plurality of independently operable gas burners in the cross-machine direction adjacent to said dryer drum and extending along the length of the dryer drum, said gas burners each including a nozzle;
- rotating said dryer drum to deliver the paper web in the machine direction into and through the hood interior and past the gas burner nozzles;
- drying the paper web on said dryer drum outer cylindrical surface;
- removing the paper web from the dryer drum;
- monitoring the paper web along the width of the paper web after the paper web has been removed from said dryer drum to determine the moisture profile of the paper web after drying of the paper web;
- and
- selectively and separately controlling the flames emitted by said gas burner nozzles as a function of the moisture profile determined during said monitoring step to direct flows of heated air to incremental width portions of said paper web while on said dryer drum to modify the moisture profile of the web produced by the paper making machine.
Dependencies are inferred from the claim text.