Hydraulic system for load cylinder of calender in e.g. cardboard machine, has pump provided adjacent to load cylinder or integrated as part of load cylinder, where load force is changed by adjusting rotating speed of electric motor of pump

摘要

The system (1) has a hydraulic pump (4) for producing volume flow (Q) of a hydraulic fluid (N), and a pipeline (7) for conveying the hydraulic fluid. A control system (10) adjusts operation of the system. The pump works in two directions. The fluid is conveyed to a pressure side (2a) of a load cylinder (2) and sucked from the pressure side of the load cylinder. Load force (Fk) produced by the load cylinder is changed by adjusting rotating speed of an electric motor (41) of the pump. The pump is provided adjacent to the load cylinder or integrated as a part of the load cylinder. An independent claim is also included for a method for low-pressure-setting of a load cylinder.