Apparatus and method for regulating the profile of a paper web passing over a Yankee cylinder in an integrated IR-dryer/Yankee hood
AssigneeValmet Paper Machinery Inc.
InventorHans Sundgvist
Life of this patent
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Abstract
A method and apparatus for regulating the profile of a paper web passing over a Yankee cylinder in an integrated IR-dryer/Yankee hood (3,2), wherein the IR-dryer (3) is placed before the wet-end block of the Yankee cylinder. The amount of air leaking into the hood (2) through the gap between the hood (2) and the Yankee cylinder (1) is reduced by passing into this gap (h.sub.o) cooling air (5) warmed up in the IR-dryer (3) and taken from said IR-dryer (3).
Claims22
A method of regulating the profile of a paper web passing over a Yankee cylinder in an integrated IR-dryer Yankee hood having lateral end portions and a gap between the hood and the cylinder and through which an amount of outside air is leaking into said hood, said method comprising:
- introducing cooling air into said IR-dryer;
- heating said air in said dryer;
- removing heated air from said dryer and passing said air to said end portions of said Yankee hood;
- and
- directing said heated air at said end portions into the gap formed between said hood and said Yankee cylinder for reducing the amount of outside air leaking into said hood through said gap.
An apparatus for regulating the profile of a paper web comprising in combination:
- a Yankee cylinder;
- a Yankee hood substantially enclosing at least part of said cylinder and defining a wet-end block and a dry-end block therein, said Yankee cylinder and Yankee hood having end portions and forming a gap therebetween;
- an air cooled IR-dryer located in front of said wet end block of said hood;
- and
- means at said end portions for passing air from said IR-dryer to said gap formed between said hood and said Yankee cylinder so as to reduce outside air from leaking into said gap.
Dependencies are inferred from the claim text.