| abstract |
Apparatus for measuring the weight per unit area of a manufactured sheet product consisting of a skeletal or reinforcing material of variable unknown weight per unit area surrounded by a bulk material also of variable unknown weight per unit area. The apparatus includes a first radiation source and detector which is relatively more sensitive to the reinforcing material than the bulk material, a second radiation source and detector which is relatively more sensitive to the bulk material than to the reinforcing material, and electronic means for combining signals from the first and second detectors to get either total weight per unit area, bulk material weight per unit area, or reinforcing material weight per unit area. |