introductory

filter pressIt is a kind of solid-liquid separation equipment, mainly used for recovering coal slurry, which can separate the tailing water of coal mine and coal preparation plant into coal cake and clear water, and improve the utilisation rate of coal; at the same time, it plays an important role in environmental protection, reduces coal slurry sedimentation ponds, and reduces the industrial occupation, and thus it is a necessary equipment for the closed loop of washing water in coal preparation plant. Dawukou coal processing plant has 6 sets of XMZ500 typeChamber Filter PressIn the use of some common failures. Some common failures of the chamber filter press are analysed and solutions are proposed.

1 Filter Press Structure Principle

1.1 Brief description of the structure

The filter press consists of ten sub-parts: oil cylinder, head plate, tail plate, filter plate, transmission part, pump station, electric part, body, cake unloading mechanism, water catching disc. The pump station and transmission part are controlled by the electric part, so that the oil cylinder presses or loosens the filter plate, completing the shedding of filter cake and the recovery of clean water.

1.2 Principle of operation

Coal slurry water enters between the filter plates through the hole in the middle of the tailboard. The water penetrates through the filter cloth and discharges from the water outlet hole in the lower part of the tank between the filter cloth and the filter plate, while the solid particles are blocked by the filter cloth inside the filter chamber, and gradually increase to the formation of the filter cake, at which time the feeding is stopped, the cylinder is opened, and the head plate is withdrawn from the filter plate and stops at about 700mm. At this time, the transmission part begins to work, so that the cake is unloaded, after unloading, the filter plate is pressed again for the next filtration, and the work is carried out week after week.

2 Filter press technical parameters

The total filtering area of the filter press is 500m2; the size of the filter plate is 1500mmx1500mmx60mm; the total volume of the filter chamber is 7.7m3; the working pressure of the filtrate is ≤1MPa; the working pressure of the oil pump is 14MPa; the travelling distance of the head plate is 700mm; the processing capacity of the single cycle is 12l; and the power of the oil pump motor is 5.5kw.

3 Common Failures

(1) The filtrate comes out black and mixed with coal sludge water.

2) Jet flow of coal slurry water from the filtrate room.

(3) Just shortly after the pressure filtration, the jet of coal slurry water is started.

4) The head plate displacement is too slow and crawls and moves.

5) Large tailboard offset.

(6) Large vibration noise at the high pressure end of the cylinder when relieving pressure.

7) The pull plate device does not return even if it frequently impacts the filter plate handle.

8) Filter press does not operate or mis-operates.

4 Failure cause analysis and solution

4.1 Inadequate filter plate components

Incomplete filter plate parts are vital to the normal operation of the filter press. Filter cloth damage, leakage can make the filtrate out of the black, the filter plate pressure density is not tight, the plate surface folder with coal sludge debris, the filter cloth folding and uneven thickness of the filter cloth, can make the filter plate between the jet stream of coal sludge water, the bottom of the filter cloth folder residual coal sludge, the bottom of the filter cloth thickening, can make the tail of the deflection is large. Therefore, the maintenance and management of the filter plate components, can reduce the damage to the filter plate to ensure that no water spray and filtrate out of the black, specifically to do: ① good placement of the rubber mat, do not take off around the flat; ② filter cloth placed on a flat, no folding wrinkled phenomenon, no broken leaks, the edge of the filter plate out of the rope should be tied, no deposits of slime; ③ regular cleaning of the cloth, depending on the use of the provisions of the situation; ④ the filter cloth into the mouth and the surrounding coal slime It should be cleaned up, so as not to cause uneven feeding, the pressure difference between the two sides of the filter plate is too large, resulting in damage.

4.2 Failure of hydraulic components

4.2.1 Noise and vibration

The noise of the hydraulic system has two kinds of mechanical noise and fluid noise. Mechanical noise: ① motor noise; ② coupling noise; ③ bearing noise; ④ tank noise. Fluid noise: ① hydraulic pump is the main source of noise, its noise accounts for about 75% of the whole system noise; ② valve fluid noise; ③ pipeline fluid noise; ④ noise caused by air pockets. Among the reasons for hydraulic pump noise are: hydraulic pump suction seal is not tight, air into; oil viscosity, flow resistance increases; oil is too dirty, oil filter clogging; oil temperature is too low; oil seal seal is not tight, from the pump shaft oil seal into the air. Noise is also too high because: relief valve spool in the valve body to move inflexible; spool valve seat clearance; oil impurities blocked damping holes and so on. Mechanical noise is mainly due to: hydraulic pump and motor coupling is not centred or loose; motor loose; bearing damage.

For this reason, in the operation of the equipment should be frequently observed and inspected, select the appropriate hydraulic oil, timely replacement of damaged oil seals and other seals, improve the quality of the fluid, keep the working environment clean, prevent the system hydraulic oil invasion of air, moisture and mechanical materials, regular oil change, careful maintenance of the tank cover, piping, filters, relief valves and so on. Inspection and maintenance of the motor and hydraulic pump, to maintain the motor and pump coupling coaxiality of not more than 0.1mm.

4.2.2 Insufficient system traffic

Causes of insufficient system flow are: tank oil level is too low, the hydraulic pump suction is poor; oil viscosity is too large or too small; pump wear and tear is serious, performance decline; cylinder, valve sealing components are damaged, the internal leakage is too large and so on. By replenishing the oil, cleaning the oil filter, replace the viscosity of the right oil, repair or replacement of hydraulic components, you can solve the problem of insufficient flow.

4.2.3 No or insufficient system pressure

Insufficient system pressure caused by the cylinder crawling, the cylinder can not hold pressure, mainly relief valve failure, pressure oil leakage outside the oil circuit, hydraulic pumps, valves, cylinders and other components wear and tear is serious, sealing components are damaged and so on. The solution is: repair or replace the relief valve, check the seals, timely repair or replacement.

4.3 Electrical faults

Electrical faults occur due to: loose wires, wrong wiring, insensitive or damaged components, loose bolts, touched or loose parts, circuit and oil circuit does not correspond, pressure relay is not adjusted appropriately, adjustable components are not adjusted, wire internal disconnection and so on.

The handling of electrical faults requires that the electrical personnel should not only be familiar with the electrical schematic diagram, the performance of electrical components, but also understand the hydraulic schematic diagram, the control of the filter press and the power transmission relationship; at the same time, to understand the working state of the filter press and the working process. According to the time of failure, in which work process, in which action occurs, to determine the region where the fault is located. For some easy to occur faults, to check first, can speed up the speed of troubleshooting, such as loose wires, pressure relay adjustment is not appropriate or damaged.

In addition, when overhauling and installing, pay attention to the original position of the parts and the size of the relationship, keep the original. Circuit, wiring oil pipe connection should be well marked, do not connect the wrong position to prevent not working properly. Pull the plate system, oil circuit correspondence, in the overhaul should be marked to prevent misplaced. In the operation, we should ensure the specified feeding concentration and keep it stable, and determine the filtration working pressure according to the performance of coal slurry. The pulling time should be controlled reasonably, which can reduce the occurrence of many failures.

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