Single-drum winders

In special cases, 9 and 3 o clock positions are also used (Fig. 8.9). This arrangement is used for paper grades with surfaces that are very sensitive to high nip loads. Due to the position of the rolls during the vrinding process the nip load can, theoretically, be reduced to zero. The necessary torque for tight core-winding is created by the center torque motor. 

The productivity of a winder is a function of its speed, its acceleration rate and its necessary stop times for set-change or reel-spool change. The stop times can be reduced by using automatic functions. To that end, equipment and controls have been developed which abridge the following functions  

Furthermore, diagnostic functions are available that help the operator to quickly detect the cause of problems on the winder and in the paper  

Modern winders are equipped with PC/PLC technologies. This allows high flexibility in adjusting the winding parameters, such as tension, torque, nip load, to the special requirements of the different paper grades. Furthermore, these technologies permit collection of aU data of the winding process for advanced analysis of 

---

The two-drum winder is often called the work-horse among the winders on account of its easy set-up combined with high productivity and efficiency and its initial investment cost being lower than with the single-drum winder. The classical two-drum winder is an economic solution but its technological hmitation is the uncontrollable nip loads that necessarily occur when the roll diameters get above nip-load critical limits, with the consequent risk of roll defects. To overcome this drawback and to achieve low-intensity controlled nip pressures various modifications have been developed. 

Fig. 8.8 Single-drum winder - finished rolls at 11 and 1 o clock positions (source Voith).

Winder configuration Friction hoist or drum hoist—A friction hoist and a drum hoist with counterweight means a larger shaft area. The most cost effective alternative was a single drum hoist. 

On smaller winders or single drum and Koepe winders when roller bearings are used, these bearings will invariably be replaced as part of the refurbishment as they are seldom designed or expected to render more than 100 000 hours continual service. 

---