Functional description of LSC System.pdf

LSC SYSTEM FUNCTIONAL DESCRIPTION )* Description: Date: 04 / 00 Hydraulic Linde - Synchron - Control - System Page: Service Training simplified schematic 1 / 6 Function of the LSC system explained by a simplified schematic with three functions Fig. 1: All three spools are in neutral position, engine is on. Stand by pressure of the HPR pump is in front of the three spools. Theoretically the pressure under this condition would correspond to the spring in the load sensing regulator (e.g. ?p= 20 bar). The stand by pressure that really ensues is higher, due to the backlash forces of the pump (some 30 bar, depending on the spring setting). Fig. 2: Only the function 1 spool is opened. Compensator 1 opens up completely, and function 1 pressure p1 is signalled to the LSC control via LS line and LS connection port. At the metering orifice of spool 1 the LS control maintains a ?p that correspondens to the spring setting of the LS control (e.g. ?p=20 bar). Q =^ A ? ? p So the pump flow Q demanded in terms of orifice area A stays always the same, even though the function pressure may vary. Fig. 3: In addition to high load function 1, low load function 2 is activated. The pressure difference between function 1 and 2 pushes the shuttle to the opposite side. As a result pressure of function 1 (= LS pressure) is now available on the left hand side of the compensator of function 2. Hence compensator 2 maintains at the metering orifice of spool 2 the same ?p as at metering orifice 1. The residu