Micro filter
The micro filter is the second cleaning stage behind the compressed air filter. Where the pre-filter separates condensate and particles from 40 µm, the micro filter of the ewo standard series goes down to 0.01 µm and retains oil mist, aerosols and the finest dust – with a separation efficiency of 99.9999 %. Available from G ⅛ to G 2, with plastic or metal bowl, plus versions for 40 and 60 bar.
How an ewo micro filter works
Unlike the pre-filter, the micro filter does not work with centrifugal force but by coalescence: the air flows through the filter fleece from the inside out, the finest oil droplets attach to the fibres and merge into larger drops that run down into the bowl. This is why a fixed direction of flow and a fixed installation position apply: vertical, in the direction of the arrow. A micro filter always needs a pre-filter upstream – without one the fleece clogs with coarse dirt within a short time.
Finding the right micro filter
Sizing for the flow rate matters: micro filters have a considerably higher pressure drop than pre-filters, and a device chosen too small costs noticeable working pressure. The overview below shows the groups in this category.
| Product group | Connection | Size | Max. pressure | Items |
|---|---|---|---|---|
| Micro filter standard | G ⅛ inlet and outlet reduced, G ¼ inlet and outlet reduced, G ⅜ | Size 30 | max. 16 bar, max. 25 bar | 27 |
| Micro filter standard | G ⅜, G ⅜ inlet and outlet reduced, G ½, G ¾ inlet and outlet reduced, G 1 | Size 30, Size 40, Size 60 | PN 25 | 24 |
| Micro filter standard | G 1 ½ inlet and outlet reduced, G 2 | Microfilter | DN 50 | 4 |
| Micro filter standard 40 bar | G ¾ inlet and outlet reduced, G 1, G ⅜ inlet and outlet reduced, G ½, G 2 | Size 60, Size 40, Size 90 | PN 40 | 5 |
| Micro filter standard 60 bar | G ¾ inlet and outlet reduced, G 1, G ⅜ inlet and outlet reduced, G ½ | Size 60, Size 40 | PN 60 | 4 |
Typical applications
- Painting and coating lines requiring oil-free air
- Food and packaging technology
- Pneumatic precision controls and proportional valves
- Measuring and testing equipment with defined air quality
- Medical and laboratory technology
- Pre-stage for adsorption dryers
Your benefits with us
- Worldwide shipping of all compressed air components and service units
- Large stock levels for many products – current lead time available on request
- Spare parts and service kits available
- Fast shipping via UPS (parcel) or freight forwarder (pallets), express delivery available on request
- Extensive hands-on application know-how
- Personal advice on selecting the right component
- Resellers receive volume-based discounts on request
- Large companies, public authorities and government agencies can order on account (request via our contact form)
Frequently asked questions
Does the micro filter replace the normal compressed air filter?
No, it complements it. The micro filter always belongs downstream of a pre-filter. Without pre-separation the fine fleece clogs quickly and the pressure drop rises sharply.
How often does the filter element have to be replaced?
As a rule of thumb annually, regardless of appearance – coalescing filters age even without visible contamination. Earlier if the pressure drop rises noticeably.
What does 0.01 µm mean on a micro filter?
That is the particle size to which the separation efficiency of 99.9999 % refers. It must not be confused with the mesh size of a screen: coalescing filters do not work on the sieve principle.
What are the 40 and 60 bar versions for?
For applications well above the usual mains pressure, such as test benches or high-pressure tools. Aluminium housing, brass bowl, sintered bronze element.
