Yankee dryer units are used in making paper, specifically to dry paper into thin sheets of tissue paper, both for craft and bathroom use. Unlike many other units in the paper-making process, the Yankee dryer exists outside the main dryer. There are some advantages to this, such as decreasing the size of the main dryer and better use of workspace. Some Yankee dryers, but not all of them, are capable of cutting and pressing the paper into sheets.
Tissue paper is a versatile, but very dry, paper that needs to go through a special drying process to get rid of all its excess moisture. When pulp — which usually has been dried to some extent beforehand — enters a Yankee dryer, it still has about 50 percent of its moisture. After going through this dryer, there is about 10 percent moisture left, leaving the paper quite crisp. The dryer normally has a conveyor unit that allows it to batch-process the pulp.
With paper making, all the units and pieces needed for the paper process normally are attached directly to the main drying unit. This includes equipment to cut, dry, wind, press and entirely finish the paper. When a Yankee dryer is used, this dryer is a separate entity from the main dryer. This may be a disadvantage for some people, because the somewhat dry pulp has to go from the main dryer to the Yankee model, but there also are some advantages.
One advantage to using a Yankee dryer is that this decreases the size of the main dryer by about 10 to 20 feet (3.048 to 6.096 meters), depending on the size of the Yankee unit. By decreasing the size, the main dryer does not take up as much room, and the Yankee unit can be placed to the side of the main dryer, allowing workers to better use the workspace. This dryer’s design also allows it to dry paper with less overall energy expenditure.
Most Yankee dryer units can only dry paper, but there are some that are capable of doing more. Those that can do more usually have a cutter to cut the dried paper, and there may be glue to help put the pulp together into sheets. A dryer with these attachments can do most of the paper-creation steps by itself without the need for another unit, though there still may need to be a smaller dryer to remove some initial moisture.