Linescan Camera System for 100 percent Moisture Measurement

摘要

Lawrence Livermore National Laboratory (LLNL), in collaboration with ABB Industrial Systems, and under the sponsorship of the Department of Energy's (DOE) Office of Industrial Technologies (OIT), has developed a new method for measuring the moisture content of a paper web process on-line with 100% coverage of the sheet. The method uses InGaAs linear arrays with associated optics and electronics to continuously image the full width of the web and measure transmitted light at 1.45i and another suitable reference wavelength between 1i and 1.6i. The method could also be used to measure paper basis weight, in addition to moisture, by adding additional hardware and optics to measure a third wavelength at 1.57i. A patent (USP: 6355931), entitled System and method for 100% moisture and basis weight measurement of moving paper, was granted by the US Patent Office on March 12, 2002 for this invention. A proof-of concept prototype system was also developed and tested on several occasions at ABB's sensors development facility in Columbus, Ohio. Based on current experimental results, the system seems particularly suitable for detecting moisture variation on a paper web for medium and heavy weight products at the dry end as well as the press section of the machine. The prototype system was scheduled to be tested at a paper mill in the fall of 2001. The test had to be cancelled as ABB was unable to provide the required field support for the test due to restructuring and down-sizing of their R&D organization.