Argo Gmbh Fur Fluidtechnik

Fsp-holding Ag

Hans Reinhardt

A filter device for filtering hydraulic fluid includes first and second subelements within a filter housing having separate inflows thereto for the respective subelements and a common outflow The first subelement has a higher filter fineness than the second subelement. Several bypass configurations are taught and include: (i) a bypass line for bypassing the second subelement by drawing fluid directly from the supply (ii) a bypass valve (FIG. ) for bypassing the first subelement; and (iii) a bypass valve (FIG. ) for connecting the first subelement inflow with the common outflow The device is compact, has an easy-to-service arrangement, and ensures protection of a hydraulic pump and highly stressed hydraulic components.

Hydraulic fluid filter device

To simplify the venting of a hydraulic circuit comprising a supply of hydraulic fluid, which is made available to a hydraulic consuming device via a pump, and a return filter comprising a filter housing and a filter element for filtering the hydraulic fluid returning from the consuming device in a return line, it is suggested that the return line comprise prior to entering the return filter a first pressure-maintaining valve which allows the return of the hydraulic fluid to the return filter only when a predetermined first pressure value is exceeded, that the return line be connected upstream in relation to the first pressure-maintaining valve to a venting device leading to the atmosphere and to a bypass line which contains a second pressure-maintaining valve and opens into the supply, wherein the second pressure-maintaining valve opens only when a predetermined second pressure value is exceeded and allows the return of the hydraulic fluid past the return filter to the hydraulic fluid supply, wherein the second pressure value is greater than the first pressure value, and that the venting device allows gas to flow out into the atmosphere but prevents the exit of hydraulic fluid.

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Bretten, Germany

Hans Reinhardt