Most people who have seen or used a floor scrubber are familiar with the conventional disk drive systems that are utilized on most machines. These machines have two or three flat disk shaped brushes with bristles affixed to the bottom. The disk brushes are pushed into the floor by the weight of the machine and the power of the brush drive motor. This type of system is very popular in commercial applications that have smooth floors that are pre-swept before they are scrubbed. A disk scrub deck is also used when more down pressure is desired; this could be for removal of some finishes or for ground-in/hardened soils.
The main pitfalls for a disk scrub deck come when there is debris on the floor or the surface is not completely smooth. Any debris or trash that is on the floor is run over by the brushes and eventually make it back to the squeegee system creating a clog in the recovery tube or streaking at the squeegee. Any un-even or low points will be missed as the disk scrub deck cannot reach below the plain that it is scrubbing.
A cylindrical brush drive system is used to pick-up the debris at the scrub deck head so that it does not interfere with the squeegee and recovery system. Cylindrical scrub decks have a debris trough that is mounted behind the scrub deck. Instead of flat brushes, the cylindrical deck uses brushes that span the length of the scrub deck and rotate like a beater bar in a vacuum cleaner. The two brushes appose each other, spinning in different directions, so that the debris will be pulled between them and flipped over the rear brush into the debris trough.