Stock feed system for a multi-layer headbox and method in the operation of a multi-layer headbox
AssigneeValmet Paper Machinery Inc.
InventorsJyrki Huovila, Erkki Ilmoniemi, Michael Odell, Antti Suonperä
Life of this patent
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Abstract
A stock feed system for a multi-layer headbox and a method in the operation of a multi-layer headbox in which into each inlet header of the multi-layer headbox, a stock concept is passed which has been produced out of the same fresh stock by adding the necessary chemicals and fillers to separated portions of the fresh stock.
Claims16
Stock feed system in combination with a multi-layer headbox having at least two inlet headers into each of which a respective stock flow is passed and which extend in a direction transverse to a flow direction of the respective stock flow, comprising
- a single fresh stock storage tank,
- a branching member,
- first passage means for continuously passing a single flow of fresh stock from said single storage tank to said branching member where said single flow of fresh stock is divided into a plurality of divided stock flows without storing said single flow of fresh stock between said single fresh stock tank and said branching member,
- second passage means for continuously passing each of said plurality of divided stock flows from said branching member into a respective one of said at least two inlet headers in said headbox without storing said divided stock flows between said branching member and said respective inlet header, and
- means for independently adding chemicals and/or fillers to each of said plurality of divided stock flows during the flow of said plurality of divided stock flows after said branching member and before said plurality of divided stock flows enter into said headbox such that stock in each inlet header has an independently controllable chemical and/or filler characteristic.
Method for regulating properties of stock being passed into a respective one of at least two inlet headers of a multi-layer headbox, the stock flowing from said at least two inlet headers through a system of tubes and further into a slice cone, comprising the steps of:
- retaining stock in a single fresh stock storage tank,
- continuously passing a single flow of fresh stock from said single fresh stock storage tank to a branching point in which said single flow of fresh stock is divided into a plurality of divided stock flows without storing said single flow of fresh stock between said single fresh stock tank and said branching point,
- continuously passing each of said plurality of divided stock flows from said branching point into a respective one of said inlet headers in said headbox without storing said divided stock flows between said branching point and said respective inlet header, and
- independently adding chemicals and/or fillers to each one of said plurality of divided stock flows during the flow of each of said plurality of divided stock flows after said branching point and before said plurality of divided stock flows enters into said headbox.
A combination of a multi-layer headbox including inlet headers and a stock feed system for feeding stock to the inlet headers of the multi-layer headbox, the stock feed system comprising
- a single fresh stock tank for retaining stock,
- a branching member,
- a first flow line having first and second opposed ends, said first end of said first flow line being connected to said single fresh stock tank and said second end of said first flow line being connected to said branching member, a single flow of fresh stock being passed through said first flow line from said single fresh stock tank to said branching member and being divided in said branching member into a plurality of stock flows without storing said single flow of fresh stock between said single fresh stock tank and said branching member,
- at least second and third flow lines each having first and second opposed ends and through each of which a respective one of said divided stock flows passes, said first ends of said second and third flow lines being connected to said branching member and said second ends of said second and third flow lines leading to a respective one of said inlet headers of said headbox, a respective one of said divided stock flows being passed through respective ones of said second and third flow lines from said branching member without storing said divided stock flows between said branching member and said inlet headers, and
- means for independently adding chemicals and/or fillers to each of said divided stock flows during the flow of said divided stock flows through a respective one of said at least second and third flow lines after said branching member and before entry of said divided stock flows into said inlet headers such that stock in each inlet header has an independently controllable chemical and/or filler characteristic.
Dependencies are inferred from the claim text.