| 摘要 |
Apparatus for measuring the moisture content of sheet material such as paper includes an infrared radiation source and detector. These are coupled to apertures in opposed paperguide plates through which the paper material flows. The apertures may be offset from one another and in conjunction with reflective coatings, of both the specular and non-specular type, on the paperguides provides simultaneous random multiple paper contacts for a typical infrared ray in its travel between the source and detector. This has the effect of increasing the effective thickness of paper, especially fine or tissue paper. For heavy paper, the foregoing technique causes radiation to be driven through to provide more accurate measurements. Diffusing windows at the radiation source and detector in addition to providing multiple radiation paths provide other advantages. |
