公开(公告)号：EP0518393A1

公开(公告)日：1992-12-16

申请号：EP92115619.6

申请日：1988-10-25

Applicant: ABB INDUSTRIAL SYSTEMS INC.

Inventor： Sturm, Steven Perry

IPC: G01N21/35 ,  G01N33/34

CPC classification number: G01N21/86 ,  G01N21/3559 ,  G01N33/346 ,  G01N2021/3148 ,  G01N2021/8663 ,  G01N2201/1211

Abstract: Apparatus and methods for use in measuring the moisture content of heavy-grade sheets of paper during their continuous manufacture. In one aspect, means employing infrared absorption techniques for determining the fiber weight per unit area of a sheet having a fiber weight of up to 1100 grams per square meter are provided. In another aspect, means employing infrared absorption techniques including the use of two moisture absorption bands and associated moisture reference bands for calculating the average temperature of the sheet are provided. The latter aspect may be used to produce an indication of moisture weight per unit area, wherein the indication is substantially independent on changes in the average temperature, and enables accurate measurement of the moisture weight per unit area of heavy grades of paper having moisture weights of up to 450 grams per square meter. The former aspect may be employed in measuring the moisture content of heavy grades of paper having moisture weights of up to 90 grams per square meter.