Patent ID: 7232518

Claim:
A filter device, comprising: a filter unit; at least one supply line and one drain line for connecting the filter unit to a hydraulic circuit; at least one cooling unit in the hydraulic circuit connected in a secondary branch line, said secondary branch line being connected in parallel to said supply line; a changeover means for conveying hydraulic medium at a definable temperature threshold to said cooling unit for cooling; a permanent supply for said cooling unit upstream of said changeover means in a flow direction of hydraulic medium in said supply line, said permanent supply being connected in parallel to said changeover means, discharging into said secondary branch line, and being another inflow line to said cooling unit; a choke in said permanent supply venting said cooling unit in low temperature operation of said changeover means without emergency manual actuation, said choke being separate from and spaced upstream from said cooling unit; an intake connection for connection to the hydraulic circuit and located downstream of said filter unit; and a back pressure valve located in said drain line downstream of said intake connection.