Laser apparatus and method for monitoring the de-watering of stock on

Abstract

An apparatus and method for measuring the de-watering performance of a forming section of a papermaking machine is disclosed which includes a laser instrument assembly having first and second laser displacement meters laterally spaced and supported above an upper run of a paper forming fabric. A head box deposits paper stock consisting of a water/fiber mixture on top of the upper run. An adjustable carrier stand supports the laser instrument assembly above the upper run of the forming fabric. The first laser displacement meter is disposed in a first position above the forming fabric so that a laser beam of the first laser meter is reflected off of the paper stock which is deposited on top of the forming fabric. The second laser displacement meter is disposed in a second position above said forming fabric so that a laser beam of the second laser displacement meter is reflected off of a bare edge of the forming fabric. The laser meters generate first and second signals representing the displacement of the top surface of the paper stock and base surface of the forming fabric. A controller receives the first and second signals and generates an output indicating the thickness of the paper stock, and hence the water content of the stock.