Regulatory considerations for process filters
With regard to regulatory aspects, one should first make sure that the process filter was manufactured in a company that at least meets the quality requirements according to ISO 9001.
If the filters are used in direct contact with food and beverages, further legal requirements must be met. For example, the filters must be tested in accordance with the requirements of the European Regulation EU Regulation 1935/2004 or Regulation 10/2011 and labeled as "Food Contact Compliant". This ensures that no ingredients from the filter migrate into the food during operation.
Other relevant regulations are European REACH and RoHS regulations, which ensure that the filter does not contain any substance of very high concern (SVHC) such as bisphenols (commission regulation - EU 2024 /3190).
An overview of REACH and RoHS regulations:
- REACH (registration, evaluation, authorization, and restriction of chemicals) ensures that the process filter is free from harmful substances that could endanger human health or the environment.
- RoHS (restriction of hazardous substances) makes process filters safer for liquid filtration systems by ensuring that they don't contain dangerous compounds like lead, mercury, or cadmium.
Finally, as per EU Regulation 2023/2006, it is crucial to verify that the filter manufacturer complies with good manufacturing practice (GMP) for materials and articles intended to come into contact with food and beverages. The majority of manufacturers provide certificates of compliance or refer to technical datasheets and brochures, for verification.
Technical considerations for choosing a process filter
To select the correct process filter, it is first necessary to clarify a few basic points:
- What is being filtered? (gas, steam, liquid)
- What temperatures is the process filter exposed to during operation?
- Is the filter in contact with harsh chemicals during operation?
When responding to these inquiries, bear in mind that certain liquid filters are additionally chemically cleaned or steam sterilized (at temperatures greater than 120°C / 248°F ). Our sales experts have in-depth knowledge of liquid filtration systems and can offer professional guidance in selecting the most appropriate Atlas Copco solution based on your process requirements, flow rates, and system specifications.
Once you have the right process filter, it is important to know where it should be used in the purification process.
Let’s take a closer look at where the process filter is used within the overall process:
- Pre-filtration: In this step, coarse impurities are removed, for example, from well water. Typically, a bag filter is used here.
- Final filtration: This stage ensures that the sterile membrane filters remove the finest impurities, such as microorganisms in process water.
Filtration efficiency: particle capture size and performance
Other important aspects are the particle capture size and the efficiency of the filter.
Particle capture size indicates the size of impurities the process filter is designed to retain.
For example, if you want particle-free water, you can choose a filter element with a particle capture size of 5μm. Water filtered with this should then no longer contain visible particles.
If you need sterile water, i.e., water free of microorganisms, a sterile membrane filter with a particle capture size of 0.2μm or smaller is required.
This ensures that even the smallest bacteria, such as Brevundimonas diminuta (diameter ~0.2 – 0.3μm), are reliably retained by the process filter.
Since no filtration process is 100% efficient, it is important to understand filtration efficiency. This is categorized as:
- Nominal filters: Allow about 2% of particles to pass through.
- Absolute filters: Provide 99.98% retention efficiency—out of 5000 particles, only one passes through.
- Sterile-grade filters: Provide the highest level of filtration efficiency, where 1 cm² / 0.155 in² of the filter surface can retain 10,000,000 bacteria of 0.2μm size, allowing only one bacterium to pass.
These aspects are important when designing a liquid filtration system.
For example, bottled water filtration typically follows a multi-stage filtration process:
- A 5μm nominal depth filter removes coarse particles.
- A 1μm absolute surface filter refines the filtration.
- A 0.2μm sterile membrane filter ensures the removal of microorganisms.
Key features of a process filter
When selecting a process filter, consider these factors:
- Filter design: Pleated filters provide a larger surface area, reducing differential pressure and optimizing energy efficiency.
- Particle capture size: Determines the smallest impurities the filter can retain.
- Durability: Choose a process filter that can withstand sterilization cycles and chemical cleaning without degradation.
How to pick the right process filter
To choose the right process filter, consider:
- Efficiency requirements: Do you need a nominal, absolute, or sterile-grade filter?
- Compatibility: Can the filter withstand temperature fluctuations and chemical exposure?
- Maintenance & cost: High-quality process filters have a longer lifespan, reducing operational costs over time.
Making the right filtration choice for efficiency and compliance
For filtering systems to remain reliable, efficient, and compliant, choosing the appropriate process filter is essential. You may improve your system and guarantee reliable operation by taking technical specifications, regulatory standards, and filtering efficiency into account.
Our sales representatives are available to extend guidance on these points and assist in designing your installation. They can also provide assistance with things like properly cleaning and sterilizing your filter elements or maximizing the intervals between changes to save CO2 emissions and running expenses.
At Atlas Copco we can help you design the right filtration system for your needs. Contact us for expert advice on selecting the best process filter for your application.
