A baler wrapper is a farm implement that is primarily used to create silage, which is a fermented grass crop that is often fed to animals or used in anaerobic digesters. After a crop has been cut and raked into rows, a baler wrapper is capable of collecting it, compacting it into cylindrical bales, and then tightly wrapping the bales in plastic. This process can also be accomplished by two separate machines, though a baler wrapper typically allows the job to be completed more quickly with less labor. These devices are usually towed by tractors and operated by a power take off (PTO), though many of them have electronic monitoring components.
After certain crops, such as straw and hay, have been cut, they must be protected from the elements. One way that this is commonly accomplished is a hay baler, which is a piece of equipment that can force the crop into compact blocks or cylinders that are then wrapped with twine. The bales can then be moved to a covered area such as a barn, or allowed to dry before being wrapped in black plastic with a separate piece of machinery. In some cases the crop needs to be turned into silage though, which is accomplished by wrapping damp grass crops in white plastic and allowing them to ferment. This can be done with separate baler and wrapper units, though a combined machine is often preferred.
Baler wrappers are capable of performing the tasks of a baler and a wrapper at the same time. These machines are typically towed behind tractors, and guided over piles of cut, raked grass crops. The baler wrapper then gathers the cut material into a drum, compresses it into a cylinder, and wraps it up before ejecting it onto a turntable. After the bale has been ejected, the baler wrapper can immediately begin compressing a new one.
At the same time that the baler wrapper is compacting a new bale, the first one can be automatically wrapped up by the other part of the machine. The bale is typically rotated on the turntable as either one or two rolls of plastic are stretched over it. This results in a weather-tight sealed bale that can then ferment into silage.
Some baler wrappers are fixed, while others are referred to as flexible. These terms refer to the drum inside a baler where the crop is compressed into a cylinder. The diameter of a drum in a flexible baler can be changed within a certain range. This can allow one baler wrapper to create bales with varying diameters. Fixed baler wrappers can only create a single bale size.