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Sterile Air & Steam

Steril Luft

Our sterile air filters are all FDA / EC validated and approved for products. “Sterile” means “free from microorganisms, that are capable of reproducing”.

A more scientific meaning of ”sterile” is that a filter is defined as a ”sterile filter”, when it is exposed to a concentration of 107 microorganisms (Brevundimonas Diminuta) pr. Cm2 filter area and the filtrate is 100% sterile and without contents of microorganisms.

Bacteria, like coli and streptococci, typically have a size between 0,3µ and 9µ, which have resulted in the sterile filter having a filtration grade of 0,2µ or better.

P-FF /MF/ SMF is a prefilter that is used to protect P-SRF / PTFE sterile filters.

P-SRF is a sterile filter that, with the help of depth filtration, reaches an absolute retention of 99,99998% in comparison to 0,01µm.

PF-PT is a sterile membrane filter that is used in the most critical applications.


All the sterile filters from Ultrafilter and 3M are validated after the FDA and the EC-1935/2004. These especially effective filters can remove bacteria down to a size of 0,2µm, and exists as a depth-, absolute-, and membrane filter. Billede: 1445    Billede: 1445


A depth filter is typically consisting of multiple layers of metallic, polymeric or inorganic material – typical used a variety of silicon named borosilicate. This type of filter specializes itself by a big filtration capacity and a high stability during operation and sterilization. This type of filter is about 99,9999% effective in comparison to a given µm size.

Membrane filter

A membrane filter is made from polymeric plastic film -typically polypropylene – These filters have a smaller filtration capacity, but here is the guarantee almost 100% retention grade and is available in different filtration grades. 0,1µm, 0,2µm and 0,45µm.


For the food and beverage industry, we recommend a depth filter. For the pharmaceutical industry we recommend a membrane filter. Both types of filters can be used and installed close to “point of use”.

It is recommended to install a central adsorption dryer, as well as microfilters and carbon filters before the sterile filters.


A sterile filter also needs maintenance and should be sterilized after use, and before use.

A sterile filter can be sterilized either in-line with steam, or in an autoclave. However, it is recommended to sterilize a sterile filter after each production batch or as a minimum every 14th day.

The sterilization temperature is between 110°C -140°C in respectively 30 and 10 minutes.

Read the sterilisation guide here.