Structure and working principle of box filter press

Abstract: This paper introduces the structure and working principle of the box filter press, and according to its structural characteristics, puts forward the maintenance measures in the use process

The causes and solutions of common faults are analyzed.
1 Overview

Box type filter press is a kind of filtering equipment, which is mainly used for solid-liquid separation of various suspensions. It can be used for coal water separation in coal mines and coal washing plants. It can improve the utilization rate of coal, reduce the discharge of waste, and play an important role in environmental protection. Although the models and specifications of filter press are different, their working principles are basically similar. Taking XM series box filter press as an example, this paper analyzes its working principle and common faults, and puts forward solutions to the problems.

Structure and working principle of 2 filter press

XM series filter press is a modern technology level advanced solid-liquid separation equipment which integrates mechanical, electrical and hydraulic. It is composed of frame part, filter part, hydraulic part and electrical part. Its structure is shown in Figure 1.

2.1 rack part

The frame part is the foundation of the machine, which is used to support the filter mechanism and connect other parts. The general frame part consists of thrust plate, compression plate, oil cylinder and main beam. When the machine is working, the piston in the oil cylinder pushes the pressing plate to press the filter plate and filter cloth between the pressing plate and the thrust plate to ensure that the slurry with working pressure is pressurized and filtered in the filter chamber.

2.2 filtering part

The filtering part is composed of filter plate and filter cloth, which is the main body of solid-liquid separation. During filtration, the slurry is driven by the feed pump and enters each filter chamber through the feed port on the thrust plate. The pressure filtration process begins, and the slurry is separated by the pressure generated by the feed pump.

2.3 hydraulic part

The hydraulic part is the power device to drive the pressing plate. The main component is an electric hydraulic station.

2.4 electronic control part

The electronic control part is the control center of the whole system.
3 use and maintenance
In the process of use, the equipment needs to be maintained, which mainly includes lubricating the matching parts, such as piston rod, bearing, etc. the accuracy and reliability of action of feedback signal devices of automatic control system (such as travel switch and electric contact pressure gauge) must be guaranteed. Only in this way can the filter press work normally.

(1) Make a good record of the operation of the equipment

Record and record the problems occurred, and timely check the equipment failure

Carry out maintenance.

(2) Keep the matching parts clean and add proper amount of lubrication

Oil to ensure good lubrication.

(3) Insulation performance test and action reliability test shall be carried out for the electric control system, and the inflexible or inaccurate components shall be repaired or replaced in time.

(4) Regularly check the sealing surface of the filter plate to keep it clean and clean, and check whether the filter cloth is folded to ensure that it is flat and intact.

(5) The maintenance of the hydraulic system is mainly to check and maintain the oil tank level, hydraulic components and the sealing of each connection port, and ensure the cleanliness of the hydraulic oil.

4 common faults and troubleshooting

4.1 material running between filter plates

The main reasons for the material running between the filter plates are as follows: insufficient oil pressure; impurities on the sealing surface of the filter plate; uneven and folded filter cloth; ultra-high pressure and flow of the feed pump; deformation of the filter plate. To solve the problem of material running between filter plates, we must solve the above reasons one by one. If the filter cloth is not flat, folded and deformed, the corresponding filter cloth and filter plate need to be replaced; the impurities on the sealing surface of the filter plate need to be cleaned; if the feed pressure and flow rate are too high, it needs to be readjusted, which is relatively simple.

However, the insufficient oil pressure may be caused by many reasons, which are mainly caused by the following reasons: ① improper adjustment or damage of relief valve; ② oil leakage in the valve; ③ wear of oil cylinder sealing ring; ④ pipeline leakage; ⑤ electromagnetic directional valve is not in place; ⑥ plunger pump is damaged; ⑤ insufficient oil level. As long as the cause is analyzed, the troubleshooting will be much easier, mainly readjustment, cleaning or replacement.

4.2 hydraulic component failure

(1) Noise and vibration. Noise and vibration are mainly caused by two aspects: one is caused by mechanical reasons, mainly including motor noise, coupling noise, bearing noise and oil tank noise; the other is fluid noise, including fluid noise of hydraulic pump, valve, pipeline and cavitation. In addition, the excessive noise may be caused by the inflexible movement of the relief valve core in the valve body, the large clearance between the valve core and the valve seat, more impurities in the oil, and blocking the damping hole.

The main causes of mechanical noise are: the coupling of hydraulic pump and motor is not concentric, the motor is loose and the bearing is damaged. Therefore, it is very important to do a good job of equipment inspection, maintenance and maintenance. Timely replacement of damaged seals, keeping the working environment clean and sanitary, preventing the system hydraulic oil from invading air and water, and changing oil regularly can reduce noise and vibration.

(2) Insufficient system flow. The causes of insufficient flow in the system are: too low oil level in oil tank, failure of hydraulic pump, wear of hydraulic components, etc. The problem of insufficient flow can be solved by adding oil, cleaning oil filter, repairing or replacing hydraulic components.

(3) There is no or insufficient pressure in the system. Insufficient system pressure will cause the oil cylinder to crawl or the oil cylinder can not maintain pressure, which is mainly caused by the overflow valve failure, oil leakage, wear of hydraulic components such as hydraulic pump, valve and oil cylinder, or damage of sealing parts. To solve the above problems, repair or replace after finding the fault point.

4.3 electrical failure

There are many reasons for electrical failure. The humidity and insulation aging of the environment may cause electrical short circuit and cause failure; loose screws may cause poor contact; overload may cause overheating and burning of the motor; bearing failure and poor coaxiality may also damage the motor; excessive dust in the electric control box may not only cause electrical short circuit, It may also cause the contactor to vibrate or not pull in and so on.

The treatment of electrical fault requires the electrical personnel not only to be familiar with the electrical schematic diagram, but also to understand the working principle of the decompression filter and the performance of the electrical components. According to the performance of the fault, the electrical fault point can be accurately judged, and the cleaning, maintenance or replacement can be carried out. Meanwhile, the firm and reliable electrical contact point can be ensured.

Conclusion

There are other faults in the filter press, such as no action in pressing and returning, bending of main beam and rupture of filter plate. The failure rate is relatively low and the cause is easy to judge, so it is not discussed.

In a word, in the process of using the filter press, careful maintenance of the equipment, patient analysis of faults, and good records are of great significance to improve the use effect of the filter press, maintain normal production, and improve economic and environmental benefits.

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