Stainless steel multi-layer plate frame filter and several common problems and solutions:

1、 Filter screen/filter plate blockage

Phenomenon: Significant decrease in flow rate, increase in filtration pressure, or abnormal turbidity of filtrate.

Reason:

Solid particles or viscous substances accumulate in the gaps between the filter screen/plate

Filter cloth aging leads to pore deformation or colloidal component adsorption and scaling

Handling method:

• Physical cleaning: Disassemble the filter screen/plate, use a high-pressure water gun (pressure ≥ 20MPa) for reverse flushing, or use a nylon brush to remove surface attachments.

Chemical cleaning: For oil or organic contamination, soak in a 5% citric acid solution for 2 hours or use a specialized alkaline cleaning agent for cyclic treatment.

Preventive measures: Install pre filtration devices (such as 100 mesh coarse filters) for high viscosity liquids and regularly monitor the distribution of feed particles.

2、 Sealing leakage

Phenomenon: Leakage of liquid at the flange connection, leakage of material at the joint surface of the plate and frame, or unstable display of the pressure gauge.

Reason:

O-ring aging or installation misalignment leads to insufficient compression

Filter plate deformation (flatness error>0.1mm/m) or scratches on the sealing surface

Handling method:

Sealing component replacement: Use fluororubber sealing rings (temperature resistance -20~200 ℃), check the elastic modulus every quarter, and replace them forcibly when the hardness drops by more than 15%.

Sealing surface repair: Use a surface grinder to correct the deformed filter plate, and control the roughness within Ra ≤ 3.2 μ m; When the scratch depth is greater than 0.05mm, it needs to be repaired by welding and polished.

Pressure control: The hydraulic system pressure is maintained at 85-90% of the design value to avoid plastic deformation of sealing components caused by overpressure.

3、 Decreased filtration efficiency

Phenomenon: The residual impurities in the filtrate exceed the standard, the moisture content of the filter cake is greater than 30%, or the filtration cycle is prolonged.

Reason:

Filter cloth/membrane damage or pore blockage rate>70%

Fluctuations in feed pressure (exceeding ± 0.15MPa) result in loose filter cake structure

Handling method:

• Filter material management: Establish a record of filter cloth lifespan (recommended replacement cycle is 200-300 cycles), and replace immediately when the permeability decreases by more than 40%.

Parameter optimization: Stabilize the feed pump speed and maintain pressure fluctuations<± 0.1MPa; Add 0.1% diatomaceous earth filter aid to the colloidal system.

• Process monitoring: Install online turbidity meters (accuracy ≤ 0.1NTU) to provide real-time feedback on filtration efficiency.

4、 Hydraulic system malfunction

Phenomenon: Insufficient clamping force, oil leakage from the oil cylinder, or no response from the pressure gauge.

Reason:

Hydraulic oil contamination (moisture content>0.1% or particulate matter>NAS level 9)

The overflow valve is stuck or the oil pump is worn, resulting in a decrease in flow rate

Handling method:

Oil maintenance: Check the cleanliness of hydraulic oil quarterly and use a three-stage filtration system (10 μ m → 5 μ m → 3 μ m) for circulating purification.

Key component maintenance: Disassemble and clean the overflow valve core (with a fit clearance of ≤ 0.005mm), and replace the gear pump with wear>0.1mm.

System debugging: recalibrate the pressure sensor and eliminate the problem of poor contact in the solenoid valve circuit.

5、 Equipment corrosion and pollution

Phenomenon: Corrosion of filter welds, detection of metal ions in filtrate, or detachment of surface passivation film.

Reason:

Chloride ion concentration>25ppm triggers intergranular corrosion (304 material)

The welding area has not undergone secondary passivation treatment

Handling method:

Material upgrade: Use 316L stainless steel (Mo content ≥ 2.5%) or titanium alloy filter plates in media containing Cl ⁻.

Surface treatment: Use a 15% nitric acid solution to circulate and passivate for 2 hours each year to repair the oxide film.

Water quality control: Install an online conductivity meter (range 0-200 μ S/cm) to monitor corrosion risks in real time.