Hydraulic and lubrication systems therefore increasingly use bypass filters and/or coolers. The advantage of these circuits is that they create stable and therefore more predictable operating conditions for both the filtration and cooling. Circulating oil in these circuits requires efficient and preferably silent circulation pumps which provide a constant flow rate at moderate pressures. Internal gear pumps, so-called gerotor pumps, have proved especially useful for these applications. They offer compact integration, are relatively insusceptible to particle contamination and have a long life. The BFP series features a range of particularly compact circulation pumps specifically designed for this area of application.