5 years ago

MDA Technologies 1/2016

MDA Technologies 1/2016


Return-suction filtration in a self-propelled harvester Argo-Hytos, the first filter manufacturer to launch a new, revolutionary filter system with the return-suction filter on the market. Since then, this filter concept for mobile machines has become a standard in many applications, because it provides far-reaching functional improvements and lowers the system and maintenance costs. CONTROL AND MEASUREMENT The reasons for the success of the return-suction filter concept can be explained as follows (Figure 1) The hydraulic system e.g. a beet harvester typically consists of: n Hydrostatic drive (1): A variable pump in the closed circuit, connected to the hydraulic motor at the axle that ensures locomotion. n Working hydraulics (2): Fixed or variable pumps that supply the users in the open or closed circuit. n Steering system (3): A variable pump in the open circuit supplies the steering system. Filter selection Filters in the hydraulic circuit guarantee function and / or wear protection. Thus one differentiates between protective filters (function protection = coarse hydraulic filters / strainers) and working filters (wear protection = fine hydraulic filters). About Argo-Hytos Argo-Hytos has an established international network of production and distribution companies. The company offers customer-oriented added value and expertise at the customers’ location. As a medium-sized family business with more than 1300 employees Argo-Hytos has more than 65 years of experience in Fluid & Motion Control and Filtration technology in mobile and industrial hydraulics. Especially in the mobile hydraulics sector Argo-Hytos has developed into one of the innovation leaders. With production companies in Germany, Czech Republic, India and China as well as numerous own distribution and assembly companies the Argo-Hytos Group is active worldwide. 42 MDA Technologies 1/2016

01 Hydraulic circuit without filtration 02 Simplified presentation of the hydraulic circuit incl. filter concept What concerns the drive is protecting the filling pump and / or the hydrostat as well as ensuring the oil cleanliness and thus the wear protection are of primary importance. Here a working filter is required. The same applies for the working hydraulics, because here as well, the pump has to be protected and the necessary oil cleanliness has to be ensured. The main focus with steering systems mostly lies on the function protection of the steering unit and this is implemented by a protective filter. This example shows how and how quickly, based on existing technical solutions, trendsetting products arise with the relevant application know-how and intelligent concepts. n A single return-suction filter (Figure 2 Pos. 4): It takes over almost all the tasks mentioned above. The filter concept for the entire machine is completed by two more filters from the Argo-Hytos portfolio: n Ventilating filter with filling filter (5): For ventilation of the hydraulic tank. The filling strainer downstream of the ventilating filter prevents coarse dirt from entering the tank while filling or with re-filling of oil due to maintenance or repair work. n Suction filter (6): At the suction side, the working hydraulics are not connected to the return-suction filter, but to carry out suction of oil from the tank via a separate and maintenance-free suction filter. In order to maintain the pre-charge pressure of approx. 0.5 bar at the connection of the filling pump, a minimum surplus between return and suction volume is necessary under all operating conditions. Production launch Since all Argo-Hytos filters are developed and manufactured by the company itself, the users can be provided with a lot of information such as e.g. pressure loss characteristics at an early stage. Thus, the suitable version was selected from the catalogue series E 598 / E 998 and installed into a harvester. This was followed by extensive testing under real conditions. After successful completion of these tests, the preparations for the production launch could be started. To make the new return-suction filter even more advantageous, in this case, a customized filter on the basis of the catalog was generated for the machine manufacturer. The series E 598 / E 998 features a very high modular connection concept with two stackable connecting plates. For the return and suction side, two connecting plate variants are already available in 03 The above picture shows the return-suction filter with three connecting plates. All lines could be guided and directly connected to the filter. Just as uncomplicated, a housing ventilation was integrated in the filter cover the standard, which can be positioned turned through 90 ° to each other. Thus, a variety of connection configurations are possible. Advantages for the user: n As the filling pump is supplied with pre-charged oil this improves the cold start characteristics of the system n By eliminating a filter, the system now employs fewer components n Reduction of spare parts and maintenance costs and overall system costs Photographs: Argo-Hytos MDA Technologies 1/2016 43