Abstract: A paper web exiting a paper manufacturing machine is monitored on a continual basis, either substantially continuously or at periodic intervals, by imaging the web with a thermal camera operating in the infrared spectrum in order to detect defects such as wet spots, patches, or streaks in the base paper web and/or irregularities in a coating layer applied to the paper web in a downstream coating unit. Based on the detected defects, the manufacturing process and/or subsequent treatment process can be adjusted to eliminate the defects.

Abstract: A method and apparatus for determining the profile of a coating layer of a paper or board web (2). The method comprises application of a coating slip to at least one surface of the web (2) at the coating head (1) of a coating machine, the measurement of the transverse temperature profile of the web (2) surface in at least a measurement point (7, 8) fitted after the coating head (1), and the determination of the profile of the web's (2) coating layer on the basis of the temperature profile measured in at least the measuring point (7, 8) fitted after the coating head (1), whereupon a change in the temperature of the web's (2) coating layer or in the difference of the temperature between the coating layer and the base web (2) is at least almost proportional to the change in the coat weight.

Abstract: The object of the invention is a method for defining the profile of a coating layer of a paper or board web (2). The method comprises application of a coating slip to at least one surface of the web (2) at the coating head (1) of a coating machine, the measurement of the transverse temperature profile of the web (2) surface in at least a measuring point (7, 8) fitted after the coating head (1), and the definition of the profile of the web's (2) coating layer on the basis of the temperature profile measured in at least the measuring point (7, 8) fitted after the coating head (1), whereupon a change in the temperature of the web's (2) coating layer or in the difference of the temperature between the coating layer and the base web (2) is at least almost proportional to the change in the coat weight.

Abstract: A paper web exiting a paper manufacturing machine is monitored on a continual basis, either substantially continuously or at periodic intervals, by imaging the web with a thermal camera operating in the infrared spectrum in order to detect defects such as wet spots, patches, or streaks in the base paper web and/or irregularities in a coating layer applied to the paper web in a downstream coating unit. Based on the detected defects, the manufacturing process and/or subsequent treatment process can be adjusted to eliminate the defects.