PTFE Membrane Filter Cartridge – Hydrophobic

Product description

Hydrophobic PTFE membrane filter cartridge for sterile gas filtration, venting and solvent service

The PTFE membrane filter cartridge – hydrophobic is designed for critical applications where sterile gas filtration, venting and protection against moisture ingress are required. Manufactured with an expanded PTFE (ePTFE) membrane, the cartridge delivers exceptionally high gas flow at very low pressure differentials while providing absolute rated retention of microorganisms and particulates.

Hydrophobic ePTFE naturally repels water and aqueous solutions, making it ideal for tank and vessel vents, sterile air and gas supply, and solvent-compatible processes. The pleated construction maximises membrane surface area for long service life and stable performance.

This product is supplied in two constructions:

• Standard version: single-layer hydrophobic ePTFE membrane

• Plus version: enhanced construction with higher capacity and improved robustness for demanding duties

Filtration principle

Hydrophobic membrane filtration retains contaminants at the membrane surface while allowing gas (and compatible solvents) to pass.

• Process gas or solvent flows from the outside to the inside of the cartridge

• The hydrophobic ePTFE membrane repels water and aqueous liquids

• Gases and compatible solvents pass through the membrane pores

• Microorganisms, particles and liquid droplets are retained at the membrane surface

This filtration principle provides:

• absolute rated microbial retention

• effective moisture barrier for venting applications

• very high gas flow rates

• stable performance at low differential pressure

Standard version – single layer ePTFE membrane

The standard version is designed for reliable sterile gas filtration and venting under typical operating conditions.

Key characteristics include:

• single-layer hydrophobic ePTFE membrane

• absolute rated microbial retention

• very high gas flow at low differential pressure

• broad chemical compatibility with solvents and aggressive chemicals

• low extractables and low TOC contribution

• suitable for steam sterilisation in place

This version is ideal for applications with standard flow demands and routine sterilisation.

Plus version – enhanced construction

The Plus version is engineered for higher throughput, longer service life and increased mechanical robustness.

Key characteristics include:

• enhanced ePTFE membrane structure with increased effective surface area

• lower pressure drop at higher gas flow rates

• improved dirt holding capacity and longer operating cycles

• reinforced internal construction for demanding operating conditions

• enhanced resistance to repeated sterilisation cycles

This version is best suited for applications where higher throughput, longer run times or frequent sterilisation is required.

Design and construction

Both versions use a pleated membrane format with robust support components to protect membrane integrity.

Typical design features include:

• hydrophobic ePTFE membrane media

• pleated membrane pack for increased filtration area

• polypropylene support and drainage layers

• rigid inner core for structural stability

• polypropylene outer support cage

• thermally bonded construction without adhesives or binders

Materials of construction

• Filter membrane: Hydrophobic ePTFE

• Support layers: Polypropylene

• Drainage layers: Polypropylene

• Inner core:

  • Polypropylene (Standard version)

  • Reinforced core construction (Plus version)

• Outer support cage: Polypropylene

• End fittings: Polypropylene

• Sealing options:

  • EPDM

  • Silicone

  • Viton®

  • Nitrile

  • FEP encapsulated

Operating conditions

Typical operating conditions include:

• absolute rated retention suitable for sterile gas service

• operating temperatures compatible with PTFE membrane construction

• high allowable differential pressure depending on temperature

• suitability for forward flow operation in gas filtration

• controlled reverse flow use depending on housing and process conditions

Exact limits depend on cartridge length, pore rating and operating conditions and are defined during configuration.

Sterilisation and integrity testing

These cartridges are suitable for validated sterile processes.

• suitable for in situ steam sterilisation

• supports multiple sterilisation cycles

• integrity testable using standard non-destructive methods, such as:

  • bubble point testing

  • diffusive flow testing

  • pressure hold testing

  • water intrusion testing

Key benefits

• Hydrophobic ePTFE membrane prevents moisture penetration

• Absolute rated microbial retention

• Extremely high gas flow rates at low pressure drop

• Broad chemical and solvent compatibility

• Low extractables and low TOC contribution

• Pleated design for extended service life

• Available in Standard and Plus constructions

Typical applications

These cartridges are commonly used in:

• sterile process gas filtration

• tank and vessel vent filtration

• fermenter and bioreactor air supply

• sterile air for packaging and production lines

• solvent filtration and chemical processing

• sterile venting on storage tanks and vessels

Configuration options

Available configuration options include:

• Standard or Plus construction

• multiple absolute pore size ratings

• standard cartridge lengths

• double open end and single open end configurations

• 222 and 226 O-ring connections with or without fin

• multiple sealing material options

This ensures compatibility with standard filter housings and specific process requirements.