|Dirty oil enters near the top of the filter vessel and flows through the filter element from the outside to the inside. The downward flow of the oil causes the solid contaminant that was displaced by the backwashing to migrate down into the sludge chamber. The clean oil exists into the clean oil chamber and out.
||A small volume of the filtered oil is ported upward to pressurize the hydraulic motor mounted at the top of the backwash mechanism which powers the backwash vanes. Normally, this oil is piped to a low pressure chamber such as the engine crankcase or a fuel oil tank. In either case, no oil is lost from the system.