Backup roller

Roll coating is widely used for uniform, whether flat or cylindrical, surfaces including fiber bundles. In a roll coating process, fibers are coated between two rollers, an applicator roller and a backup roller coating is fed continuously to the applicator roller by a feed roller which runs partially immersed in a coating bath and the backup roller pulls the fibers by rotating in opposite directions. Slow... 

This is a machine with relatively large work rolls, generally without backup rollers, and a lot of space between the rolls (Fig. 15). It is the least sophisticated of the options and is generally designed for removal of coil set only. It is a simple bending machine generally having five, seven or nine rolls. 

Because of the backup roller support for the work rolls, considerably more clamping pressure may be exerted on the material without having the adverse effects that would occur from the roll deflection in a spread-center, non-backed up, machine. 

Most flatteners or levelers have a four-high configuration that is, they have an upper and lower set of work rolls and an upper and lower set of backup rollers—four levels of rolls, two on the top and two on the bottom (Fig. 29). This is the conventional setup. It is also the simplest and easiest to maintain. 

Under certain circumstances, with very sensitive or soft-surfaced materials, the four-high leveler can produce a striping effect. The pressure of backup rollers on the hardened work roll surface may burnish a small area of the work roll... 

The configuration would be as follows work roll, intermediate roll, and backup roller that is, three layers of rolls. If there are intermediate rolls on both top and bottom of the machine, we refer to this as a six high (Fig. 30). The drawback is that the extra set of intermediate rolls makes the machine much... 

Direct vertical hydraulic cylinder adjustment of the backup roller flights has not generally been adopted by the equipment builders because of the need for precision and accurate location of backup flights, whether under load or not. 

Because of the steep pitch required, slides are limited in application. They are most commonly used to bridge the gap between roller-conveyor systems on two floors, because the roller conveyor can take the container off the slide rapidly and ehminate or reduce the chance for collisions. Slides may also be used when containers can be chuted from an upper floor to a manually loaded carrier. The use of several rollers at the feed point is recommended for easy dehveiy to the sloping section. If the drop is short and containers light, a roller cleanout will prevent backup of containers on the slide. The slope of gravity slides is a function of container weight, size, and friction characteristics and should be selected with care to be sure that containers do not move either too swiftly or not at all. Slides usually use flat steel sheet. 

The second classification of straightening device is known as a precision leveler. Precision levelers are distinguished by small-diameter, closely spaced rollers with backups and the ability to flex those rollers. They normally have a far greater number of work rollers than do conventional straighteners. Because they work the material much harder and their rollers can be flexed, precision levelers can be used to remove not only coil set but also wavy edges, and center buckles, as well as trapped stresses within the material so that it will stay flat after processing through a die or rollformer. 

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