Date of Award
Bachelor of Science
Computer control of paper industry processes is becoming a very significant segment of the industry. Of major importance is on-line measurement and control of moisture and basis weight in the web, those two parameters affect practically every other sheet characteristics. Accurate closed loop control is essential to keeping the product within customer-demanded specifications.
Board mills in particular utilize large quantities of waste paper, with the rate of usage expected to increase from 20.5 percent in 1970 to 26 percent by 1985. The concentration of contaminants will increase at a similar rate. One such contaminant, carbon black, will reduce the effectiveness of on-line IR (infrared) moisture sensors. Carbon black is the most important pigment in printing inks, since it colors virtually all black inks.
All materials will absorb or reflect light energy, the amount being a function of the material characteristics and the wavelength of the light beam. Carbon black being a black body is nearly an ideal absorber. When present in a web a paper the carbon black will absorb IR wavelengths used to detect water in the sheet, yielding erroneous moisture content measurements.
Experimental results showed that the relationship between carbon black level and the deviation from actual moisture is linear.
Beck, William A., "The Effect of Carbon Black on TR Moisture Measurements and Beta Ray Basis Weight Measurements" (1978). Paper Engineering Senior Theses. 58.