EDGE-CUTTING 5218053 - Caterpillar

When the engine is running and the control switches are in the AUTO position, the conveyor system delivers asphalt from the hopper to the screed at the appropriate rate. In order to deliver asphalt at the appropriate rate, the hydraulic oil must flow in and out of the system and to the motors at varying flow rates.The hydraulic oil for pump (18) is supplied from two sources through supply lines (20). When the machine is initially started, the hydraulic oil is supplied by the hydraulic tank. After the machine is started, the hydraulic oil is supplied by the return oil from the conveyor system and the vibratory system. The excess return oil flows back into the hydraulic tank.The left conveyor system and the right conveyor system is driven by only one pump for each side. The motors operate independently of each other. Only the left side conveyor lines will be explained in this section. Both the right side conveyor lines and the left side conveyor lines are identical. Both the right side conveyor lines and the left side conveyor lines operate in the same manner.
Illustration 11 g00624128
Hydraulic Schematic for the Left Side Conveyor System (1) Return line for control valve (2) Return line (3) Cooling and flushing oil line (4) Left drag conveyor motor (5) Case drain line (17) Case drain line (18) Left conveyor pump (19) Case drain line (20) Supply line (21) Signal line (22) Cooling and flushing oil line (23) Left auger conveyor motor (24) Left side control valve (25) Manual override valve (26) Manual override valve (27) Pilot line (28) Flow control valve (29) Orifice (30) Internal filter (31) Bypass valve for the auger motor (32) Dump valve (33) Flow control valve (37) Pilot line (38) Check valve (39) Oil line (40) Oil line (41) Oil lineOil flows from left conveyor pump (18) into left control valve (24). Manual override valve (26) is closed and the valve blocks the flow of oil. The oil flows through orifice (29) to flow control valve (28) .Flow control valve (28) is open a certain amount that depends on the strength of the signal from the conveyor electronic control module. A stronger signal will open the valve wider. When the valve opens wider, more oil flows back to the hydraulic tank through a check valve. This decreases the oil pressure in pilot line (27). This decreases the opening of manual override valve (26). The smaller opening restricts the amount of flow to