The function of the unloading circuit of the horizontal waste plastic baler is to make the hydraulic oil output by the oil pump flow directly into the oil tank when the oil pump motor is close to zero pressure when the oil pump motor does not stop running, so as to reduce power consumption. This circuit is generally used in situations where the baler system needs to be intermittent for a short period of time within a working condition and the motor oil pump does not want to stop running.

(1) Unloading circuit using the middle position function of the horizontal baler reversing valve. The oil pump is unloaded using the middle position function of the three-position reversing valve (M type, H type, K type). Unloading circuit using the middle position function of the M-type electro-hydraulic reversing valve. This circuit is simple, but when a general electromagnetic reversing valve is used for unloading, the pressure shock during reversing is large. If an electro-hydraulic reversing valve is used, the reversing pressure shock can be reduced.

(2) Electromagnetic overflow valve unloading circuit. The horizontal baler circuit is mainly composed of an electromagnetic overflow valve (a composite valve composed of a pilot overflow valve and a two-position two-way electromagnetic reversing valve), a pressure relay (or an electric contact pressure gauge), etc. When the system pressure reaches the rated pressure, the pressure relay sends a signal, and the two-position two-way reversing valve connects the control oil circuit of the pilot relief valve to the oil tank, and the relief valve opens to unload.

(3) Unloading circuit using an unloading valve. When the actuator is in an empty stroke, the high-pressure pump and the low-pressure pump of the baler supply oil to the system at the same time to increase the movement speed of the actuator. When the system pressure rises to the set value of the unloading valve due to load changes, the unloading valve opens and the low-pressure pump unloads. At this time, only the high-pressure pump supplies oil to the system to load the system. The function of the one-way valve is to separate the high and low-pressure oil circuits to prevent the high-pressure oil from flowing back to the unloading valve.

Working Principle:

The material to be packaged enters the baler feed channel through the conveyor belt. When the material layer reaches the predetermined height, the main cylinder starts to compress and continues to squeeze the material. When the length of the compressed material reaches the set packaging length through the tail counter, the hooking device starts, and the hooking rod lifts the lower connecting wire through the chain drive and returns to the initial position to stop. Then the winding mechanism starts, and the bale connecting wire is knotted by the wire claw on the winding device. When the number of knots reaches the set value, the connecting wire will be released by the rotation of the winding claw, and the bundling is completed. The bundled material continues to move forward along the discharge channel due to the continuous extrusion of the rear material. When it reaches the tail discharge port, the tail extrusion cylinder drives the connecting rod mechanism to compact the material again. Finally, the material is squeezed out of the slideway and the packaging is completed. During the packaging process, the tail extrusion cylinder always squeezes the material intermittently, and the pressure is released when the material is output.