Coating weight measuring and control apparatus and method
AssigneeHoneywell-Measurex Corporation
InventorsEdward Belotserkovsky, John A. Dahlquist
Life of this patent
Estimating the term…
Abstract
A sensor and a method for determining the basis weight of a coating material containing CaCO.sub.3 on a substrate is described. The determined basis weight is insensitive to changes in the amount of substrate material underlying the coating. Signals from the sensor may be used in the control of a coating mechanism to provide a coating having a uniform basis weight.
Claims17
A coating sensor for sensing a coating material on a substrate, wherein the coating material contains CaCO.sub.3 the sensor comprising:
- a radiation source disposed to direct a beam of infrared radiation into the coated substrate;
- a radiation receiver disposed to detect at least a portion of the beam emerging from the coated substrate, the receiver being configured to detect the amount of radiation in first and second separate wavelength regions of the radiation spectrum wherein the first region ranges from about 3.6 to 3.9 .mu.m and the second region ranges from about 3.9 to 4.1 .mu.m and to produce first and second signals therefrom, respectively indicative of the amount of detected radiation in the first and second regions, and wherein the first region is selected for radiation which is sensitive to the amount of substrate underlying the coating and the second region is selected for radiation which is approximately equally as sensitive as radiation in the first region to the amount of substrate underlying the coating, but which is also sensitive to the CaCO.sub.3 of the coating, the sensitivity of the radiation in the first region to the CaCO.sub.3 being different than the sensitivity of the radiation in the second region to the CaCO.sub.3.
A method for sensing a coating material on a substrate, wherein the coating material contains CaCO.sub.3 comprising steps of:
- (a) irradiating the coated substrate with radiation including wavelengths in at least first and second separate wavelength regions of the infrared electromagnetic spectrum wherein the first region ranges from about 3.6 to 3.9 .mu.m and the second region ranges from about 3.9 to 4.1 .mu.m;
- (b) detecting the amount of radiation emitted from the substrate and coating material in the first and second separate regions, the first and second regions being selected such that the radiation in the first region is sensitive to the amount of substrate underlying the coating material and the radiation in the second region is approximately equally as sensitive to the amount of substrate underlying the coating material as the radiation in the first region, and further wherein the radiation in the first and second regions have unequal sensitivity to the amount of the CaCO.sub.3 in the coating.
Dependencies are inferred from the claim text.