Mining companies have previously used morefilter pressact asSolid-liquid separation equipmentIn recent years, the filter press has been gradually replaced by the filter press. Filter press has simple structure, easy operation, convenient maintenance, long service life, stable filtration operation and high solid phase recovery rate. Advantages of the filter press are the reduction of unit filtration area, strong adaptability to the material, high filtration pressure, low moisture content of the cake (10%), especially for the separation of viscous materials, but also its unique superiority, has been widely used in metal beneficiation, smelting, tailings, dyeing, petrochemicals, pharmaceuticals, food, coal washing and wastewater treatment and other industries.

Filter Press Overview

The beneficiation plant usesAutomatic Chamber Filter PressThis filter press is a XMZ200/1200 model with a total filter area of 200 m2 and a frame size of 1,200 x 1,200. The filter press is model XMZ200/1200, with a total filtration surface area of 200 m2 and a frame size of 1,200×1,200. The filter press is a product of the 1990s, when the control system used electro-hydraulic control technology, i.e., the combination of a hydraulic system and an electrical system, due to the electrical technology conditions at that time. All the work of the filter press is related to the hydraulic system, and the movement of the main cylinder of the filter press and the movement of the filter plate mover are all completed by the hydraulic station and related electro-hydraulic valves. Due to the adoption of electro-hydraulic control technology, the control system structure principle is complicated, and it is difficult to investigate in case of failure. When the filter press fails, it is easy for the clampers and electricians to pass the buck to each other, thinking that it is the other party's cause, and it is difficult to judge and solve the faults for a while. According to the long-term use of maintenance experience, that type of filter press overhaul must be combined with mechanical and electrical technology, according to the hydraulic system schematic diagram and the electrical system schematic diagram of the comprehensive analysis and search, in order to quickly and accurately determine the cause of the problem and determine the solution.

Structure and working principle of automatic filter press

The structure of automatic filter press consists of frame, pressing mechanism, filter plate moving mechanism, filtering mechanism, hydraulic station, electric control cabinet and so on. The working process of automatic filter press is: filter cloth cleaning - head pressing - feeding and draining - filtering - head releasing - discharging slag piece by piece (cyclic process). Filter cloth cleaning - head pressing - material supply and discharge - filtration - head release - slag discharge by piece (cyclic process) Operation mode of filter press The operation mode can be divided into automatic control and manual control, and the automatic control is realised by the joint control of mechanical, hydraulic and electric, and there is a feedback signal to ensure the safe and reliable operation of the equipment. Recently, the automatic filter press has been experiencing frequent malfunctions of the pulling plate, which are not constant but occur intermittently.

According to the manufacturer's operating instructions, the causes of pull-plate removal failure: loose adjustment screws; damaged proximity switches; stuck spools; spools are stuck. According to the experience, the reason for the failure of pulling the board: pressure relay damage; control line aging damage. After checking the above problems do not exist, the control line inspection did not find abnormalities, mainly because the fault is sporadic, can not be detected.

Filter press pulling plate fault analysis and solution

Preliminary analysis of the hydraulic system failure The hydraulic system is related to the pull plate is the pressure relay and solenoid reversing valve, after the inspection and replacement of the two valves, the system works normally. After checking and replacing the two valves, the system worked normally. The output line was analysed as a problem. The control line was checked and found to have been used for more than 10 years, and had been in contact with oil for a long period of time, but no abnormality was found. The control line has been used for more than 10 years, and it has been in contact with oil for a long time, and there is aging condition. Analysed as PLC failure Because of the failure from time to time, maintenance clampers and maintenance electricians blame each other, and can not determine the specific cause of the failure. After a period of operation, no further failure of the pulling board, initially concluded that the pressure relay or the line caused by the impact. Later the fault occurred for a long time, after the electronic control system to determine the PLC failure. PLC normal operation when the panel indicator light is on, the corresponding terminals are energised, when the indicator light is off, the terminals are de-energised. The actual situation is that the panel indicator lights up and off alternately according to the work requirements, but the output terminals are continuously energised, and it is finally determined that the PLC output terminals are faulty. The PLC for the Omron series of products, after contacting the manufacturer row of technicians to assist in modifying the PLC programme, will be damaged terminals to adjust the worse for the spare terminals, completely eliminate the problem.

concluding remarks

In addition to modifying the PLC programme, the solution to the automatic filter press pulling plate fault can be to replace the PLC with a new one (at a relatively high cost), or to use a speed relay instead of a pressure relay (most of today's filter presses use a speed relay), or to use a frequency converter control instead of a pressure relay or a speed relay. With the development of electrical technology, manufacturers have gradually separated the hydraulic system from the electrical system, which makes operation and maintenance relatively simple, with a low failure rate, and makes it easy to find the cause of a malfunction. Electromechanical itself is related, whether it is maintenance pliers or maintenance electricians, must have a certain degree of electromechanical expertise. As the saying goes: "Mechanical and electrical are not separate". In actual production, often mechanical maintenance and electrical maintenance is separate, if conditions allow, should be included in the electromechanical maintenance of a type of work, improve the professional and technical level of maintenance workers, effectively combine mechanical and electrical technology, which is conducive to the development of work and improve work efficiency. The above are some personal insights into the maintenance of filter presses, and I hope to play a role in the use of maintenance and management of filter presses by colleagues in the industry.