• Two Drum Winder/Horizontal SlittersPrior to the 1960s a paper mill did not have much choice in winder designs. The two drum winder with equal size drums and a horizontal slitter section was the dominant, and in a practical sense, the only winder concept available. A couple innovative winders were produced but did not have wide acceptance which resulted in a very short life.
  • This vintage winder used cast iron frames and wound the rolls on a full width winder coreshaft on either iron pipe or paper cores. Maximum winder speed was determined by a rough formula of 2.5 times the maximum paper machine design speed. The winder operation was manual with a cycle time more than adequate for the times. Paper machines in this period were operating in the 2000 FPM maximum speed range. The winder drive used a single motor drive with a belt tie between the two winder drums. Tissue machines used a similar winder the notable exceptions being a surface driven unwind stand and a coreshaft weight relieving system to maintain bulk. A modern version of the horizontal sheet run two drum winder is still produced today in very limited numbers for special applications.



Two Drum inder/Vertical Slitters
  • The vertical slitter section 2 drum winder appeared in the late 60's and was popularized in the 70's. There was a lot happening in winding in the 60's. The early 60's saw the first two motor- torque differential drives, load cell tension systems, sectional paper carrying rolls, dual component spreader elements and other significant WINDER developments.. The first automatic slitter sections appeared in the late 60's. Shaftless winding, a unique and different concept was just coming to being. The change that had the greatest impact on winder designs was the advent of fabricated winder frames as opposed to cast iron. This permitted a flexibility in design not possible in the past.
  • To accommodate the changes in paper grades, basis weights, sheet densities and other paper properties, there was a great flurry of roll structure control systems and larger diameter winder drums to improve shipping roll quality to meet the demands of larger shipping roll sizes. As the two drum winder matured and was mechanically opimized to the fullest the "traditional" two drum winder was found lacking when winding large, heavy shipping rolls of dense grades of paper, particularly in the coated and super calendered papers.
  • The duplex winder concept emerged in the early 60's but due to it's poor productivity performance, winder builders continued to develop new two drum winder designs to wind heavier shipping rolls and maintain the productivity advantages of the two drum winder.
Unequal Diameter Winder Drums Working in concert with paper mills, winder builders designed new and innovative concepts to extend the usefulness of the two drum winder . One of the earlier developments was the "unequal drum diameter" concept. When winding on the two drum winder with unequal drum sizes the major portion of the winding roll weight was transferred to the broader nip of the larger winder drum reducing the PSI load of the paper winding on the drums resulting in less "wound in tension" caused by drum nip load.
Soft Nip Technology Another development was "soft nip winding". Again the goal was for a broader drum nip to reduce the tension being wound into the roll. This winder concept uses a resilient material on one of the winder drums that can deform under load, producing a wider nip. In some installations, the "soft nip" concept is further enhanced by the application of a narrow based articulating rider roll that minimizes the effect of caliper variations in the web.
Air Support Technology The "air support winding concept" uses a completely different approach. This concept reduces drum nip load by pumping air into the pocket formed by the two winder drums and the winding roll of paper. The air produces a lifting effect on the winding paper rolls thereby "releiving the weight of the paper on the winder drum nip.
Three Drum Winder Another very unique approach is the "three drum winder" concept. This concept embodies both the two drum and duplex approach. The concept in effect is a pair of two drum winders, the common center drum acting as the second drum on each of the two drum winders. The winding rolls in a set are wound on alternate pairs of drums. This concept has several advantages not the least of allowing individual rolls to be weight relieved.
Belted Winder Technology
Yet another unique configuration is the "belted winding" concept. The Belted winder replaces one of the winder drums of the traditional two drum with a belt arrangement. It is only similar to other concepts in that the goal is to broaden the nip that supports the winding roll of paper. As the roll builds in size during the winding process, more of the wound roll surface bears on the belt arrangement-in essence widening the drum nip proportionate to wound roll diameter.
All the "enhanced" two drum winder concepts described are operating successfully today in the marketplace. For the most part these designs are grade specific and in many instances the concepts are adaptable to retrofit on existing traditional two drums.
This scrapbook contains conceptual sketches of winder configurations in present use in the Pulp & Paper Industry. The sketches are not drawn to scale and use generic sheet runs and are not intended to represent equipment as designed and sold by winder manufacturers. For specific details, arrangements, specifications or other issues concerning the concepts illustrated, contact a manufacturer that produces such concepts.

Go to Luigi'S' Scrapbook #2 - Duplex Winding

Luigi Bagnato-Paper Industry Web