Comparative Analysis of Preheater Wrap Control System

A corrugator line should be equipped with multiple preheaters, both single cylinder preheater and multiple preheater. Among them:
Medium quality control cylinder——Before the paper feeding into the single facer, plus steam spraying equipment;
Linerboard preheater——To adjust the angle-wrap of paper web before the paper enters the  single facer;
Multiple preheater——To heat single corrugator and linerboard before the paper web is fed into the double-sided machine.
In the production process of three-layer and five-layer corrugated board, if there is a problem of applying glue, the solution is: through the other direction into the preheater for reverse preheating, that is, to heat the other side of the paper and reverse removal of paper moisture.

Usually, a three-layer cardboard production line (one set of single facer) should be equipped with two preheater groups, and a five-layer cardboard production line (two sets of single facer) should be equipped with three preheater groups. If a single facer needs to run a large amount of heavy kraft paper at high speed (more than 350 grams/square meters), equipped with three preheater groups will also play a good role. Seven-layer board production line, heavy duty corrugated board production line can have up to five preheater groups, so that the angle-wrap is more diversified.On the preheater, the smaller the angle between the angle-wrap adjusting roll and the paper guide roll, the smaller the contact area between the paper width and the drum dryer; The larger the angle between the angle-wrap regulating roll and the paper guide roll, the larger the contact area between the paper width and the drum dryer. Because the preheater to balance the humidity and moisture content of the base paper, to ensure the smooth production of cardboard, so the preheater has to maximize the angle-wrap adjustment, in order to timely change the  heating area of paper web on the drum dryer.

f the preheater has an encoder interface connected to the production pipe, it can automatically control the angle-wrap——the angle-wrap can be automatically adjusted according to the speed and paper quality, and the length of angle wrap can be calculated automatically.
If the preheater does not have an encoder interface to the pipe, the operator manually adjust the angle-wrap. Depending on the operator's personal experience to adjust the size of the angle-wrap is very easy to cause the paper web too wet or too dry, resulting in the production quality of the subsequent process.
Comparative analysis of advantages and disadvantages of angle-wrap control system(Table 1)
 In addition, the current drum dryer of preheated in the market is generally fixed. But equipment suppliers have also developed more advanced configurations that allow the durm dryer to rotate. If the preheater drum dryer can rotate, the surface area of the drum dryer in contact with the paper will no longer be fixed, which is conducive to the uniform use of steam in the drum dryer, on the other hand, it can be more energy saving.

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