Chemical Liquid Filter – Part 2: Liquid Accuracy, Flow Matching & Filter Structure Selection

Chemical Liquid Filter – Part 2: Liquid Accuracy, Flow Matching & Filter Structure Selection

2. Liquid Accuracy Selection (Micron Rating)

Liquid accuracy is measured in microns (μm). A smaller micron value means finer liquid. However, finer liquid does not always provide better performance. If the filter rating is too fine for a highly contaminated liquid, the filter may clog quickly and increase maintenance frequency.

The correct filter selection should balance:

· Required cleanliness level

· Particle size distribution

· Contamination concentration

· Filter replacement cycle

2.1 Coarse Liquid: 50–200 μm

Main Purpose:
Protect pumps and pipelines by removing large particles.

Suitable For:

· Sand

· Large crystals

· Metal fragments

· Process debris

Installation Position:
Usually installed before the pump suction inlet.

Main Benefits:

· Protects pump impellers and mechanical seals

· Reduces equipment damage risk

· Prevents large particles from entering the pump chamber

Common Equipment:
Y-type strainers and basket filters.

2.2 Medium Liquid: 10–50 μm

Main Purpose:
General chemical liquid purification.

Suitable Applications:

· Electroplating circulation systems

· Chemical cleaning solutions

· Industrial process water

Typical Industries:

· Copper plating

· Nickel plating

· Surface treatment processes

Benefits:

· Removes suspended particles

· Improves chemical solution quality

· Extends the service life of fine filters

2.3 Fine Liquid: 0.5–5 μm

Fine liquid is the most common range for precision industrial applications.

Applications:

· PCB electroplating

· Chemical nickel plating

· Lithium battery electrolyte circulation

· Precision chemical processing

Benefits:

· Removes micro particles

· Improves coating quality

· Reduces defects such as pinholes, rough surfaces, and uneven coating

Common Filter Materials:

· PP cartridge filters

· PTFE cartridge filters

2.4 Ultra-Fine Liquid: 0.1–0.45 μm

Used for extremely clean production processes.

Applications:

· Semiconductor manufacturing

· Pharmaceutical production

· Ultra-pure water systems

· High-purity electronic chemicals

Requirements:

· High cleanliness

· Low particle release

· No metal contamination

Recommended Materials:
PTFE membrane filters and PFA components.

2.5 Filter Material Selection

Different filter materials provide different chemical resistance and temperature performance.

3. Match Filter Capacity With Pump Flow

A common mistake is selecting a filter only according to pipe size. The filter capacity must match the actual pump flow rate.

Basic Selection Rule:

Filter rated flow ≥ Pump flow × 1.2–1.5

The additional capacity compensates for:

· Dirt accumulation inside the filter

· Increasing pressure loss during operation

· Flow reduction caused by filter blockage

Recommended Filter Types by Pump Flow

3.1 Monitor Pressure Difference

Pressure difference is one of the most important indicators of filter condition.

Normal Operation:
Pressure drop < 0.08 MPa

Recommended Filter Replacement:
Pressure drop > 0.15 MPa

A blocked filter may cause:

· Reduced flow rate

· Increased suction resistance

· Pump cavitation

· Motor overload

· Higher energy consumption

4. Select the Correct Filter Structure

Different industrial applications require different filter designs.

4.1 Cartridge Filter System — Precision Chemical Liquid

Structure:
A sealed housing containing cartridge filter elements.

Advantages:

· High liquid accuracy

· Compact structure

· Excellent sealing performance

· Low chemical leakage risk

Applications:

· PCB plating lines

· Chemical nickel plating

· Lithium battery electrolyte circulation

· Precision surface treatment

Limitation:
Not suitable for liquids with heavy solid contamination.

Recommended Solution:
Install a coarse filter before the cartridge filter to remove large particles.

4.2 Bag Filter System — High Contamination Liquid

Structure:
A replaceable filter bag installed inside the housing.

Advantages:

· Large dirt-holding capacity

· Easy filter replacement

· Lower maintenance frequency

· Suitable for high particle loads

Applications:

· Copper etching systems

· Chemical wastewater

· Chemical process liquids

· Crystal-containing solutions

Limitation:
Lower liquid accuracy compared with cartridge filters.

4.3 Y-Type Strainer — Pump Protection Filter

Structure:
A simple pipeline filter with a removable screen.

Main Function:
Protect pumps from large particles.

Applications:

· Chemical pumps

· Magnetic drive pumps

· Self-priming pumps

Installation:
Usually installed on the pump suction side.

Important Note:
A Y-strainer is a protection device, not a precision liquid system.

4.4 Filter Press — Solid Waste Treatment

Advantages:

· Handles high solid content

· Efficient solid-liquid separation

· Suitable for continuous waste treatment

Applications:

· Electroplating sludge

· Chemical waste treatment

· Industrial wastewater

· Solid recovery systems

4.5 Heated / Jacketed Filter — High Temperature Applications

Structure:
A filter housing equipped with a heating or cooling jacket.

Heating Media:
Hot water or thermal fluid.

Main Purpose:
Prevent chemical crystallization during liquid.

Applications:

· Hot plating solutions

· High-temperature chemical processes

· Crystallizing chemical liquids

Conclusion

Chemical liquid selection is not only about choosing a smaller micron rating. A reliable liquid system must consider liquid accuracy, chemical compatibility, flow capacity, contamination level, and operating conditions. Proper filter matching helps protect pumps, improve production quality, and reduce maintenance costs in industries such as electroplating, PCB, lithium battery, semiconductor, and chemical processing.