BOLLFILTER Type 6.21 is designed for filtration of continuous volumes of fuel oils. It's used for the protection of diesel injection pumps. When required, the media is cleaned one segment at a time by a rotating backflush unit, without interrupting the filtration process. The working pressure remains almost constant and the flushing volumes are extremely low. The filter can optionally be equipped with a heating medium connection on the bottom of the housing and with a bypass filter.