How To Select Filter Cartridge and Housing ?- Meeting Notes

2026-05-09 vwalve By vwalve
How-To-Select-Filter-Cartridge-and-Housing
Select Filter Cartridge and Housing

1. Pre-Filters (Security Filters):

1.1 Filter bags: Cost-effective

1.2 High-flow pleated filter cartridges: Made with 25μm membrane rated as 5μm filtration accuracy;Achieves 5μm nominal rating through pleated 25μm membrane structure (increased filtration area),utilizing multi-layer interception principle to enhance precision

1.3 PP melt-blown cartridges: Temperature resistance <80°C, 80-90% retention rate, prone to fiber shedding

1.4 Nylon cartridges: Excellent chemical resistance, ideal for organic solvent filtration, minimal fiber shedding;Typical temperature resistance 60-80°C, not suitable for high-temperature applications

1.5 String-wound cartridges: Lowest retention efficiency

1.6 Resin cartridges: Better temperature/pressure resistance than PP, but higher cost and limited usage

1.7 Polyester cartridges: Temperature resistance <120°C;Moderate chemical resistance, commonly used for aqueous solutions, better cost-performance than nylon

1.8 Stainless steel cartridges: Temperature resistance ~200°C;Reusable (backwashable), suitable for high-viscosity or low-corrosive high-temperature liquids, but lower precision (typically ≥10μm)

1.9 High-flow cartridges have lower dirt-holding capacity than small-flow types due to larger surface area. Not recommended for >50ppm particle concentration (prone to clogging). Drawing and wall ironing emulsions typically contain 200ppm aluminum powder, making high-flow pleated cartridges unsuitable.Recommended alternatives: PP melt-blown (cost-effective) or string-wound (pre-filtration), followed by precision filter in series for enhanced accuracy

2. Post-Filters (Precision Filters):

2.1 PP microfiltration pleated cartridges: 3-layer membrane structure, can add 2-3 precision layers to achieve absolute 5μm rating with 99% retention rate

2.2 Absolute precision cartridges (<5μm, 99.99% retention rate):

PTFE cartridges

PES cartridges

3. Key selection factors: Temperature requirements, fluid chemical composition, acid/alkali resistance (determine material selection including cartridge skeleton and O-ring). Filtration requirements: relative vs absolute precision. Relative precision (nominal rating) means 80-95% retention of >5μm particles. Absolute precision (absolute rating) guarantees 99.99% retention of >5μm particles. High-demand industries (semiconductor, phone screen, pharmaceutical) require absolute precision, often 0.2-0.3μmRelative precision corresponds to ‘Nominal Rating’, absolute precision corresponds to ‘Absolute Rating’

4. Pall high-flow cartridges: Top-sealed, similar to filter bags

4.1 Parker high-flow cartridges: Widely used, double inner bottom O-rings, easy installation

4.2 3M high-flow cartridges: Limited market use, 4 bottom guide blocks, single outer O-ring, difficult installation

4.3 Microfiltration pleated cartridges offer better sealing than high-flow types due to smaller bottom O-rings (lower deformation and leakage risk). Single-open end cartridges seal better than double-open end types, which rely on gland and spring (higher leakage potential)

5. Select cartridge first based on fluid and operating conditions, then choose housing size/type according to cartridge specifications and installation space. O-ring material selection:NBR for oil resistance, FKM for acid/alkali resistance, VMQ for high-temperature applications

·  Pre-filtration (Security): Requires onlynominal precision, priority order: String-wound → PP Melt-blown → Filter bags

·  Final Precision: Requiresabsolute precision, options: PP Pleated / PES / PTFE

·  Solids >50ppm or metal powder: Avoidhigh-flow pleated cartridges

·  Temperature >80°C: Exclude PP/Nylon, choose Polyester/Stainless Steel

·  Organic solvents/strong acids/alkalis: Prioritize Nylon/PTFE, avoid PP

6. Filter Housing Selection Principles

  1. First determine cartridge model, quantity, and dimensions;
  2. Then match housing diameter, pressure rating, port configuration, and installation space;
  3. Housing material must be corrosion-resistant to the fluid;
  4. Mandatory accessories: Vent, drain, and differential pressure monitoring ports.