Corrugating process

The major starch sources are corn, potato, waxy maize, wheat and tapioca. Refined starches are supplied in powder form or as slightly aggregated pearl starch.16 Unmodified (native) starch is rarely used in the paper industry, except as a binder for laminates and in the corrugating process. Most starches for use in papermaking are specialty products that have been modified by controlled hydrolysis, oxidation or derivatization.17... 

Mixtures of waxy, regular, and high amylose starches are degraded with a mixture of sodium persulfate, sodium sulfite, boric acid, and caustic, and cooked at 90°C (194°F) and about 33% solids to form a starch adhesive that hardens on cooling. The cold corrugating process is described in other references. " ... 

Touzinsky, G. F., and Sprague, C. H., Fundamentals of the Cold Corrugating Process Adhesives and Bonding, Annual Meeting—TAPPI, 427-432 (1982). 

Typical overall coefficients to start a rough sizing are as below. Use these in conjunction with the NTU calculated for the process. The closer the NTU matches the plate (say between 2.0 and 3.0), the higher the range of listed coefficients can be used. The narrower (smaller) the depth of corrugation, the higher the coefficient (and pressure drop), but also the lower the abdity to carry through any particulate. 

Plate-and-frame exchangers transfer heat by passing cooling fluids and process fluids between large corrugated panels. Crevices exist between closely spaced panels that stimulate localized attack. Plates... 

Compared with traditional plate-and-frame exchangers, this design relies on a more loosely corrugated chevron pattern, which provides exceptional resistance to clogging. The plates are designed with few, if any, contact points between adjacent plates to trap fibers or solids. Some styles of this exchanger use wide-gap plates on the process side and conventional chevron patterns on the coolant... 

Figures 10-101, lO-lOJ, and 10-1 OK indicate the process flow patterns for single tube units and for multiple corrugated tubes in a single plain shell. These units are suitable for heating or cooling process fluids containing high pulp or fiber content or suspended particulates. The heat transfer coefficients are improved when compared to plain tubes as the turbulence improves the performance. The units can be arranged in multiple shells for parallel or series flow. The manufacturers should be contacted for details.

Increasing the stiffness capability of any material (plastic, metal, etc.) can be accomplished by thickening the product. Result is use of more materials and more processing costs. As reviewed, other approaches include the use of ribs, corrugations, and sandwich constructions. 

Semichemical pulping comprised 6% of U.S. pulp production in 1993.1 Semichemical pulp is often very stiff, making this process common in corrugated container manufacture. This process primarily uses hardwood as furnish. 

Contaminant removal processes depend on the type and source of secondary fiber to be pulped. Mill paper waste can be easily repulped with minimal contaminant removal. Recycled postconsumer newspaper, on the other hand, may require extensive contaminant removal, including deinking, prior to reuse. Secondary fiber is typically used in lower-quality applications such as multiply paper-board or corrugating paper. 

In case that corrugated base papers are not any more produced from recycled paper, as it is typical for testliner and medium in Germany, virgin fibres would have to be used. The corresponding paper grades as kraftliner would be produced from kraft pulp and fluting from semi-chemical pulp. For the simplified calculation of the required wood demand for the fibres, an average process yield of 60% (kraft pulp = 50%, semi-chemical pulp = 70%) is used. The substitution of the... 

A heavy type of open mill with deeply corrugated rolls, used for the preliminary breakdown of rubber compound prior to the processes of extrusion and calendering. 

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