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US 6,190,726 B1Granted
Method and apparatus for coating a moving web of paper or paperboard using a controlled coating jet
AssigneeValmet Corporation
InventorsJukka Koskinen, Jukka Linnonmaa
Life of this patent
Estimating the term…
Abstract
A method and assembly for coating a moving web of paper or paperboard by means of a coating mix jet which is directed to the surface of the web without mechanical support. The present invention is based on applying a desired amount of the coating mix to the web via a narrow-gap slit orifice, and by measuring the coat weight on the web, adjusting the position of at least one lip of the slit orifice to achieve the desired weight and cross-machine profile of the applied coat.
Claims23
A method for coating a moving web of paper or paperboard comprising:
- applying coating mix to a surface of a moving web of paper or paperboard in a jet ejected from a slit orifice of an applicator, the slit orifice extending across at least a portion of a width of the moving web, the coating mix being applied at a volume rate of flow through the slit orifice, the slit orifice being formed by a first lip and a second lip;
- measuring a weight of the coating mix that has been applied to the surface of the moving web by the jet;
- and
- controlling the volume rate of flow of coating mix ejected from the slit orifice of the applicator at a plurality of points across at least a portion of the width of the web so that the coating mix applied to the surface of the web achieves a desired coating thickness after drying of the web and the applied coating, the volume rate of flow being controlled based upon measuring of the weight of the coating mix that has been applied to the web by the applicator, the volume rate of flow being controlled so that the desired coating thickness is obtained without doctoring of the applied coating mix.
1 more element
An apparatus for coating a moving web of paper or paperboard comprising:
- an applicator for applying coating mix to a surface of a moving web of paper or paperboard in a jet ejected from a slit orifice of the applicator, the slit orifice extending across at least a portion of a width of the moving web, the slit orifice being formed by a first lip and a second lip;
- a means for measuring a weight of the coating mix that has been applied to the surface of the moving web by the applicator;
- and
- a control means for controlling the volume rate of flow of coating mix ejected from the slit orifice of the applicator at a plurality of points across at least a portion of the width of the moving web so that the coating mix applied to the surface of the web achieves a desired coating thickness after drying of the web and the applied coating, the volume rate of flow being controlled based upon measuring by the measuring means of the weight of the coating mix that has been applied to the moving web by the applicator, the volume rate of flow being controlled so that the desired coating thickness is obtained without doctoring of the applied coating mix.
1 more element
Dependencies are inferred from the claim text.