Headbox, the Heart of the Paper Machine
After dilution and screening in the approach flow, the suspension consisting of fibers, additives and water must be fed uniformly in web width to the screen part of the paper machine. For this it is pumped to the headbox via a tapered manifold flow spreader as well as several pipe manifolds. Pressure and speed must be constant in these areas. Depending on the web speed, the pressure can vary up to 145 psig (10 bar), which determines the quantity of stock applied.
Direct Pressure Measurement with the VEGABAR 64
The pressure measurement in the headbox is used for speed control of the mixing pump and is the most important pressure measurement on the paper machine. For that reason, it is implemented redundantly. The measurement loops are placed near the discharge lip on the tender (operator) side and drive side of the machine. The pressure on the tender side is used for control, the value on the drive side for plausibility checking. This must be a high precision measurement and reactionless. The optimum solution is the VEGABAR 64 in completely front-flush version, accuracy class 0.05 and high protection IP 68.
