Applying digital image technology to pulp and paper

Describes the application of a 2D color image display to monitor various paper properties of a paper machine reel. These properties include caliper, opacity, moisture and basis weight. The conventional method of determining the paper quality of an entire reel was to perform statistical calculations on a profile-to-profile basis of paper properties in both machine direction, length and cross-machine direction, and width of the sheet. On a profile-by-profile basis, it can be somewhat difficult for mill personnel to determine whether the entire reel is within the desirable grade specifications or not, or whether the specification is only out of limits at certain sets or rolls within the reel. This difficulty can be overcome by use of digital imaging technology. An image display can be used to monitor the entire reel sheet for various paper properties. This means less time will be required for statistical calculations. Feedback from analyzing the reel image would enable mill personnel to identify possible problems associated with the paper machine controls. In addition, trimming information can be derived from the reel image noting if any undesirable streaks are present in the sheet. The reel image display was developed as a graphical tool for the paper machine, as part of a mill-wide information and optimization system (MOPS). This paper presents a case study of using this display at the Alberta Newsprint Company (ANC) pulp and paper mill. The overall benefits of this display are demonstrated by using actual property profile data recorded from their paper machine