The Argo Hytos E Series Return-Suction filters are for operation in units with hydrostatic drives, when the return flow is under all operating conditions higher than the oil flow of the feed pump. In machines with a hydrostatic drive and combined working hydraulic system, return-suction filters replace the suction or pressure filters previously required for the feed pump of the closed-loop hydrostatic drive circuit as well as the return filter for the open-loop working hydraulic circuit. While each circuit operates independently with separate filters, the combination of the two circuits via the return-suction filter causes interaction between the circuits. If the design criteria described below are taken into account, you can take full advantage of the benefits provided by the return-suction filter concept, thus making sure that your system performs reliably even under extreme operating conditions.