Working principle and fault solution of quick opening filter press

                           Working principle and fault solution of quick opening filter press

 The new 2.4 million t/a coal preparation plant of Wuyang Coal Mine was completed and put into use in January 2008. The coal preparation process adopts dense medium cyclone + TSS separator + flotation. The filter press is an important part of the coal slime water treatment system. Whether the operation is normal or not restricts the production of the coal preparation plant. Compared with the old plant, the production capacity of the 2.4 million t/a new plant has been greatly improved. The selection of the filter press Two KzG300/1500×2000-U/X quick-opening filter presses . This machine is a quick-opening high-pressure diaphragm filter press,Diaphragm Filter Press which is designed and manufactured with electromechanical and hydraulic integration, and has a high degree of automation. The push pin is moved up three times to pull the plate to unload, ply the plate, and the thrust pin is moved down to further reduce the moisture content of the filter cake and increase the processing capaci

1.1 The composition of the quick-opening filter press The quick-opening filter press consists of a frame, a main beam, a filter plate, a thrust plate, a partition, a compression plate, a machine base, an oil cylinder body, a discharge mechanism, and a hydraulic station. , Electrical control part.

1.2 Working principle of quick-opening filter press The filter plate of the quick-opening filter press is composed of a diaphragm plate and a box plate. The diaphragm plate between the plates is pressed tightly with the box plate and filter cloth to ensure that the pressurized filter pulp is filtered under pressure in the filter chamber. Because of the diaphragm plate, compressed air can be passed through the air inlet on the diaphragm plate Squeeze the filter cake to further reduce the moisture content of the filter cake. You can also pass high-pressure air through the feed port at the end of the thrust plate to pass through the filter cloth layer to carry out intermediate air flow, and blow out the intermediate mud. There is also a part of the main engine that completes the compression and release of the power device. Under the action of the electric control cabinet system, a part of the work of the system is completed through the oil cylinder, oil pump, and hydraulic components. When the system is compressed, each filter chamber is sealed. It is used for filtering, otherwise it is loosened for unloading. The unloading part is mainly composed of two geared motors, transmission shaft, sprocket, chain and other main parts, and works under the action of the electrical system.When the pressure plate is loosened, the thrust pin moves 1-1, the motor at the position of the support seat is started, and the first part of the filter plate is pulled through the chain to pull the cylinder seat and the pressure plate, and the motor at the position of the thrust plate is started to drive the partition to be pulled apart. The second part of the filter plate is reversed through the signal transmission in the electric control cabinet, and the unloading process is completed by driving the partition to pull the remaining filter plate. The machine has two working modes, automatic and manual. In the automatic mode, the entire action process of the filter press will run sequentially according to the design program without manual intervention. The operating process is as follows: first close the air switch, select The switch is set at the automatic position, press the program button, the motor of the pump station starts to start, and at the same time, the electromagnetic valve is released to charge, the pressing plate retreats, and the pressing plate automatically stops backing up when it touches the limit proximity switch, and at the same time, the electromagnetic valve of the thrust pin is charged, stopping The push pin moves up and stops when it touches the upward movement limit switch, and at the same time the motor of the pump station stops running, the pull plate motor (thrust plate position) starts, and drives the oil cylinder base to move (one pull plate unloading) until the limit switch motor stops ,At the same time, the pull plate motor (thrust plate position) starts to drive the partition to move (the second pull plate unloading) to the limit. After the switch is approached, the motor reverses and drives the partition to move in the opposite direction (three pull plate discharge) to the limit. The motor of the proximity switch stops, and at the same time, the pull plate motor (thrust plate position) starts to drive the cylinder seat to move (the closing plate) to the limit. After the position switch, the thrust solenoid valve is powered off, and at the same time the compression solenoid valve is electrified to perform the compression action. After reaching the upper limit of the pressure, it will enter the pressure holding state, and the motor of the pump station will stop and start feeding. Such a working cycle is completed. In the manual mode, each action of the filter press is completed by manually operating each button. This method is mainly used for equipment debugging. In addition, in the process of unloading, if manual assistance is needed or other situations are required, the unloading device can be used to stop the unloading. After the interruption, the manual cleaning is completed, and the drawing plate continues.

2 Fault analysis There are three types of fault analysis through the problems that have occurred in the use of the filter press for more than a year:

①Electrical failures: mainly limited position proximity opening failures, solenoid valve failures, relay failures, electrical contact pressure gauge failures, etc.

②Mechanical failures: damage to the filter cloth of the filter plate, damage to the valve, damage to the climbing chain, failure of the pull plate mechanism, etc.

③Hydraulic system failure: mainly hydraulic valve damage or blockage.

3 Troubleshooting methods

3.1 Electrical faults

1) When a certain program does not act during the program running, for example: the thrust pin moves down and does not compress after a timeout, first check whether there is any problem with the proximity switch when the thrust pin moves down and in place, if there is any problem, just replace the proximity switch, if it is on If the proximity switch is not extinguished when it is moved to the right position, it will also cause the timeout of moving down to replace the proximity switch.

2) The solenoid valve of the pumping station is faulty, resulting in no compression or loosening. In addition, the thrust pin does not move up or down. The solution is to check whether the corresponding solenoid valve is powered or the solenoid valve coil is burnt out, just replace it.

3) The electric contact pressure gauge is faulty, and the pressing timeout or emptying timeout is a problem with the electric contact point. The treatment method is to adjust or replace it.

4) If the solenoid valve of each valve is faulty, if a certain air control valve does not open when it should be opened or does not close when it should be closed, check whether the solenoid valve coil of the valve is powered, or whether the coil is burnt out. The treatment method is to check the circuit and relay or Replace the coil, if the valve that should be opened is opened, and the valve that should not be opened is also opened, then it is possible that the solenoid valve line is connected to electricity or the junction box is flooded.

3.2 Machine failure

1) There is material leakage between the filter plate and the diaphragm filter plate. The reason is that there are sundries between the filter plates, the filter cloth is not flat and folded or the filter cloth is broken. Treatment method: clean up the sundries, tidy up and replace the filter cloth.

2) The filter plate is broken, the reason is that the sandwich is caused by the damage of the filter cloth, the filter cake is pressed before it fills the filter chamber, and the inlet and outlet of the filter plate are blocked. Treatment method: replace the filter cloth in time, squeeze the filter cake after it is filled with the filter chamber, and clean the inlet and outlet.

3) The shaft bearing of the pull plate is damaged or the shaft is broken, resulting in abnormal noise when pulling the plate or the pull plate is inclined when pulling the plate, and the unloading should be stopped in time. Treatment method: replace the shaft and bearing, the breakage of the small chain of the pull plate will also cause the filter plate to tilt, and the unloading should be stopped in time to replace the small chain.

4) Insufficient pressure maintenance, the reason is that the piston seal ring is worn and the oil circuit leaks oil. Solution: Replace the seal and check the oil circuit.

5) The filtrate is not clear, the reason is that the filter cloth is worn, the filter cloth is not selected properly, and the seam of the filter cloth is opened. Treatment method: replace the filter cloth.

3.3 Hydraulic system failure

1) Insufficient pressure maintenance, the reason is that the hydraulic control check valve is out of control, treatment method: replace and clean the hydraulic control check valve.

2) The oil pressure is insufficient, the reason is that the overflow valve is broken, the oil level is insufficient, the oil pump is worn, the valve is broken or the joint leaks oil, the oil cylinder seal is worn and the oil leaks in the valve, the treatment method: repair or replace the overflow valve, refuel, replace the oil pump, Tighten the fitting, replace the O-ring or replace the seal.

3) There is noise in the hydraulic system. The reason is that air is sucked into the cylinder, the fasteners are loose, and the viscosity of the hydraulic oil is high. The treatment method: open the air release valve to release the air, tighten the loose fasteners, and replace the hydraulic oil.

4 Conclusion Through the in-depth understanding and analysis of the common faults of the quick-opening pressure filter for more than one year, a reasonable treatment method is proposed. In daily use and maintenance, as long as the principle is well grasped and serious operation can improve the pressure The stability of the filter can better guarantee the normal production of the coal washing plant.

Filter press technical support: +86 18927439782