The working process of the filter press can be divided into high pressure unloading, loosening, plate taking, pulling plate, compaction, pressure maintaining, and pressure compensation. High-pressure unloading: After the feeding filtering process is completed, press the "program start" button, and the filter press will start unloading. The solenoid ball valve removes the high pressure in the oil cylinder to prevent the hydraulic system from impacting when the pressure plate is loosened.
The high pressure unloading time of the filter press is controlled by PLC. When the delay time is reached, the filter press will automatically switch to the release state of the press plate. Release: start the oil pump motor, release the electromagnetic reversing valve, the hydraulic station controls the oil to the front chamber of the cylinder. The piston rod drives the pressure plate back, and the filter chamber opens to start discharging. When the pressure plate contacts the release limit switch, the filter press automatically enters the plate removal state. The traction motor of the filter press starts to drive the plate puller to take the plate.
After the inverter sends out an overload signal, it will automatically reverse and enter the pull plate state. In the process of pulling the board, if the inverter sends out an overload signal, it will enter the board removal state, that is, the cycle of board removal, pull board, and completion of the board unloading process. Pressing in: After the pull plate action is completed and the trolley limit is contacted, the oil pump motor runs, the electromagnetic steering valve is energized, the hydraulic station controls the oil in the high pressure chamber of the cylinder, and the piston rod drives the pressure plate forward, thereby pushing the filter plate to perform a pressing action.
When the filter plate is in contact with the thrust plate, the pressure of the hydraulic system rises. When the upper limit of the set pressure is reached, the filter press automatically switches to the pressure holding state. Pressure compensation: due to leaks and other reasons, the pressure of the hydraulic system will gradually drop. When the pressure drops to the lower limit, the filter oil will automatically start, and press the pressure to return the pressure gauge to the upper limit. Hydraulic part The hydraulic part is the power unit of the main engine. Under the action of the electronic control system, various tasks are completed by the oil cylinder, oil pump and hydraulic components. It can realize functions such as automatic pressing, automatic pressure compensation, high-pressure unloading, and automatic loosening.
When the automatic press of the filter press starts to squeeze, the oil pump motor and the electromagnetic reversing valve are energized, and the motor drives the oil pump to start supplying oil to the high pressure chamber of the oil cylinder. Under the action of the oil pressure, the piston rod moves forward, pushing the pressure plate to compress the filter plate. When the pressure reaches the upper limit of the electric contact pressure gauge, the motor and the electromagnetic directional valve lose power. The motor stops automatically. Enter the pressure holding state, at this time the system pressure is determined by the pressure relief valve.
When the oil pressure drops to the lower limit of the electric contact pressure gauge (or the set value of the pressure relay), the lower limit contact of the electric contact pressure gauge sends out an electric signal, the motor and the electromagnetic reversing valve are energized, and the oil pump supplies oil to the back cavity of the oil cylinder to compensate for pressure. When the pressure reaches the upper limit of the electric contact pressure gauge, the motor and the electromagnetic directional valve yv1 lose power, the motor automatically stops running, and the automatic pressure compensation is completed.
After a delay of 15 seconds, the solenoid ball valve loses power. The motor and the solenoid directional valve are energized. The motor drives the oil pump to supply oil to the low pressure chamber of the oil cylinder. The piston rod drives the pressure plate to move backward. When the pressure plate is in contact with the release limit switch, the electromagnetic commutation cabinet loses power, the pressure plate stops moving, and the PLC sends a signal at the same time, and the variable frequency motor pull plate system starts to work.