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FAQ Guides Of Filter Press: Filtration, Maintenance & Troubleshooting

Published time:14 July 2022

In the process of using the filter press, we will inevitably encounter some problems. Now we will summarize the common filter press problems from the following aspects: filtration, maintenance, troubleshooting, etc., And introduce various schematic diagrams including cloth installationpipelinewiring scheme, and electrical schematic diagram.

Filtration

1. What are the factors that affect the filtering effect?
The filtration effect will be various according to the slurry’s condition, such as solid content, temperature, ph value, particle size, etc. Or even some slurries need to add chemical powders to regulate the slurry’s filtering performance, such as filtration aid, flocculant, etc. And the final cake will be different.

2. Is it normal that the filtered liquid is not very clean at the beginning of filtration?
At beginning of filtering, the filtered liquid will be not very clean, because the precoat is not formed. Please continue to work and it will be better after a while.

3. Is little leakage reasonable?
Little leakage is reasonable, because of cloth capillarity/wicking. If big leakage happens, please increase some closing pressure (a little).

4. How to deal with the sudden turbidity of filtrate?
Please observe the filtered liquid, if suddenly filtrate is muddy, please close the tap. (For close filtrate filter press, please stop the machine.) Then check the clothes.

5. When is the filtering finished?
If the pressure is higher and the liquid flow is very small, the filtration is finished.

6. What should I do if the filtration time is too long or the cake cannot be made?
If the filtering time is too long or the cakes can not be formed, please try to lower the liquid content, such as increasing precipitation time; using thickener; adding filtration aid and flocculant, etc.

7. How to clean the cake?
If cakes need washing, please close the taps on the washing plates and feeding valve, then fill in the water to wash the cakes. The water pressure should not be over the rated pressure. The washing time is decided by the filtering effect.

8. How to do to achieve a better dehydration effect?
To realize a better dewatering effect, the cakes can be blown by compressed air and the method is the same as the above. The compressed air also can be fed in via a feeding hole. Or use membrane filter press directly.

How to Maintain The Filter Press?

  • Operators must know the operation instructions and strictly operate the machine according to the manual.
  • Please use good filter clothes and the clothes must be flat.
  • Please often check every part of the product whether in reliable condition: the fastener is fixed; the hydraulic system has no leakage; every driving part works smoothly etc.
  • Regularly check the hydraulic oil’s quality. The hydraulic system must keep clean. The oil temperature should be no more than 60 ℃. Often check the oil filter. When it’s winter, please ensure the temperature is more than 15℃.
  • After changing the oil pipe, then use the machine the first time, please keep off the high-pressure oil pipe.
  • Every use, please check the working situation. If there is abnormal, please turn the machine off and repair it.
  • A monthly Insulation test for electric parts is necessary.
  • The feeding pressure, closing pressure and the slurry temperature must be strictly under the rated value. And if the following situation happens, the filter press must not be turned on: the number of plates is not enough; the max distance of the closing plate is smaller than the cylinder distance.
  • As for the mechanical filter press, please pay much attention to the closing conditions. Please do not run with overload for a long time.
  • After discharging, please wash the clothes and plates.
  • If long time does not use the machine, please store it in a dry and ventilative place. The relative moisture should be no more than 80% and the temperature should be around 0-40 ℃. The hydraulic system should be filled with oil. The surface of the naked structure should paint with anti-rust oil.
  • Plates and frames should keep off materials that may cause damage, and please keep away from heat, rain, sun, etc.
  • When using a membrane filter press, before air squeezing, the chamber must be filled with slurry. And before opening the plates, the compressed air must be discharged in advance. Otherwise, plates might be broken. While filtering, please pay much attention to air pipes, if abnormal happens, please close the air feeding valve and discharge the air. After repair, it can be used again.

Troubleshooting & Solutions of Filter Press

FaultsPossible ReasonsSolving Methods
The hydraulic system has serious noise or pressure is not stableThere is no oil in the tank or the oil pipe is blockedAdd oil, clean the pipes oil
Plate sealing surface has impuritiesClean it
There has air in the oil pipesDischarge the air
The pump is damagedReplace or repair
Relief valve can not work stablyReplace or repair
Oil pipe shakesFix them
The closing pressure is not enough or even no pressureThe oil pump is damagedReplace or repair
The pressure adjustment is wrongAdjust it again
Oil viscosity is lowChange the oil
Oil leakageRepair
While squeezing plates, the pressure is not enoughThe high-pressure relief valve is blocked or damagedReplace or repair
Reversing valve is damagedReplace or repair
The seal of the big piston is brokenReplace
“O” seal of the small piston is damagedReplace
The oil pump is damaged.Replace or repair
The pressure is not adjusted rightlyRegulate it again
While the cylinder is coming back, the pressure is not enoughThe low-pressure relief is blocked or damagedReplace or repair
The seal of the small piston is damagedReplace
The “O” seal of the small piston is damagedReplace
The piston crawlsThe oil circuit has airReplace or repair
The transmission box has a serious noiseBearing is damagedReplace
Gears are damagedReplace or repair
Serious leakage between platesDeformation of plates and framesReplace
There are impurities on the sealing surfaceClean
Clothes are not flatReplace or flat them
Closing pressure is not enoughIncrease the closing pressure
Deformation of plates or framesThe filtering pressure is too highDecrease the pressure
The temperature of the slurry is too highDecrease the temperature
The closing pressure is too highAdjust the closing pressure
The filtering speed is too fastSlow down the filtering speed
The inlet is blockedClean the inlet
The machine stops during workingDo not stop during working
Often pressure complementOne-way valve is not good closedReplace
Cylinder has leakageReplace the seal
The direction valve can not workThe valve plug is blocked or damagedClean or replace it
Plate shifter can not be pulled backThe pressure of the oil motor is lowRegulate it
The pressure of the pressure relay is lowRegulate it
Membrane is damagedAir pressure is not enoughLower the air feeding pressure
The feeding slurry is not enoughFilled chamber with slurry
The membrane might be punctured by impuritiesRemove the impurities
Beams bendThe foundation is not firm and flatRepair or rebuilt

Filter Press Schematic Diagrams

● How to Install The Cloth?

cloth installation

● Wiring Scheme

wiring scheme

● Pipeline

Pipeline

● Electrical Schematic Diagram

electrical schematic diagram

Note: The above drawings are just for your reference. Please install according to the drawing on your electrical cabinet.

 

Extended Reading

How to Install, Debug and Operate Filter Press Safely?
Filter Press Manual

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