Apparatus for measuring coating thickness on an applicator roll
AssigneeThe Dow Chemical Company
InventorsJoseph L. Garner, Edwin L. Wittbrodt
Life of this patent
Estimating the term…
Abstract
An apparatus and method are disclosed for measuring the amounts of a coating material on an applicator roll. A beam of light is projected so that only a first portion thereof is intercepted by the coating material on the applicator roll. At least a fraction of the remaining light portion passes through an aperture defined by a slotted shield member and the coated roll surface, said fraction varying with the thickness of said material on the roll surface, and detector means disposed to measure said variable fraction.
Claims15
In a coating apparatus, means for measuring the amount of coating material on an applicator roll, comprising:
- a. an applicator roll associated with a source of said material;
- b. shield means spaced from the roll surface;
- c. a light source capable of emitting a beam of light in a direction which is not parallel to the axis of the cylindrical surface, said light source being positioned such that when the coating material is deposited on the cylindrical surface, a first portion of the light emitted therefrom is intercepted by the coating material deposited on the cylindrical surface and a second portion passes across an arc of the coated cylindrical surface, said shield being aligned such that a first part of the second portion of light is intercepted thereby and a second part of the second portion of light passes through the aperture formed by said shield and roll surface;
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- d. a detector means capable of measuring at least a fraction of the amount of said second part of light, the amount of said fraction varying with the thickness of the coating material when same is deposited on the cylindrical surface.
In a coating apparatus, means for measuring the amount of coating material at a plurality of points across a coating roll, comprising;
- a. an applicator roll associated with a source means of said material;
- b. shield means spaced from the roll surface and associated therewith at each said point;
- c. a light source for emitting a beam of light in a first direction essentially parallel to the axis of the cylindrical surface;
- d. a series of reflectors, each reflector being capable of reflecting a segment of the light in a second direction which is not parallel to the axis of the cylindrical surface and such that when the coating material is deposited on the cylindrical surface a first portion of each segment of reflected light is intercepted by the coating material deposited on the cylindrical surface and a second portion of each segment of reflected light passes across an arc of the coated cylindrical surface, said shield being aligned such that a first part of each said second portion of light is intercepted thereby and a second part of each said second porition of light passes through the aperture formed by a said shield and roll surface at each said point;
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- e. a series of detector means, each detector means being capable of measuring at least a fraction of the amount of a said second part of one said segment of reflected light, the amount of each of the light fractions varying with the thickness of the coating material when same is deposited on the cylindrical surface.
A device for determining the amount of a coating material on a rotating cylindrical surface which is transferred to a sheet passing over said surface;
- said device comprising a cylindrical surface capable of receiving the coating material thereon and a first and second implement, each implement having:
- a. shield means having a side thereof spaced from the cylinder surface;
- b. a light source capable of emitting a beam of light in a direction which is not parallel to the axis of the cylindrical surface and being positioned such that when the coating material is deposited on the cylindrical surface, a first portion of the light emitted from each light source is intercepted by the coating material and a second portion passes across an arc of the coated cylindrical surface, said shield being aligned such that a first part of the second portion of light is intercepted thereby and a second part of said second portion of light passes through the aperture formed by said shield and cylinder surface;
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- c. a detector means capable of measuring at least a fraction of the amount of said second part of light, the amount of said fraction varying with the thickness of the coating material on the cylindrical surface when the coating material is deposited thereon;
- said first implement being positioned such that it is capable of measuring the amount of the coating material on the cylindrical surface prior to its contact with the sheet, and the second implement being positioned such that it is capable of measuring the amount of the coating material on the surface after said contact.
Dependencies are inferred from the claim text.