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

An apparatus for measuring the de-watering performance of a forming section of a papermaking machine, said forming section including an endless paper forming fabric which travels about a plurality of rolls;

• said paper forming fabric having an upper run, a head box for depositing paper stock consisting of a water/fiber mixture on top of said upper run of said forming fabric;
• a plurality of de-watering mechanisms disposed sequentially underneath said fabric along said paper run of said fabric for removing water from said stock;
• wherein said apparatus comprises:
• a first laser displacement meter disposed in a first position above said forming fabric so that a laser beam of said first laser meter is reflected off of said paper stock deposited on top of said forming fabric;
• a second laser displacement meter disposed in a second position above said forming fabric so that a laser beam of said second laser displacement meter is reflected off of a bare edge of said forming fabric;
• a carrier stand for supporting said first and second laser displacement meters in said first and second positions above said upper run of said forming fabric.

A method of measuring the de-watering performance of a forming section of a papermaking machine wherein said forming section includes an endless paper forming fabric which travels about a plurality of rolls;

• said paper forming fabric having an upper run, a head box for depositing paper stock consisting of a water/fiber mixture on top of said upper run;
• a plurality of de-watering mechanisms disposed sequentially underneath said fabric along said upper run for removing water from said paper stock, wherein said method comprises:
• providing a measurement reference position;
• measuring a first distance from said reference position to a top surface of said paper stock;
• measuring a second distance from said reference position to a bare surface of said forming fabric which is devoid of said paper stock;
• generating first and second electrical signals corresponding to said first and second distances and possessing said first and second signals to generate an output signal representative of a thickness of said paper stock as an indication of the water content of said paper stock at said reference position.