Filters for compressed air treatment units

The air treatment unit filter separates water droplets and dirt from compressed air before they reach the regulator, tool or machine. That is why it comes first in the assembly. The condensate collects in the bowl and is drained manually, semi-automatically or automatically.
Here you will find separate filters from 7 ranges of air treatment units: plastic, metal for 18 bar, filters for potentially explosive atmospheres and stainless steel up to 60 bar. Looking for a compressor intake filter? You will find it among the compressor intake filters.
Filters by range
“Inlet up to” is the highest air line pressure the filter withstands. Filtration is the fineness of the element. The flow applies to the largest thread of the range.
| Filters for air treatment units — range comparison | ||||||
|---|---|---|---|---|---|---|
| Range | Connection | Inlet up to | Filtration | Condensate drain | Flow up to | ATEX |
| P2 | G 1/4" | 12 bar | 20 µm | manual | 1,200 l/min | – |
| I3 | G 1/8", 1/4" | 13 bar | 20 µm | semi-automatic | 1,200 l/min | – |
| A2 | G 1/4", 3/8", 1/2", 1" | 10 bar | 5 µm | semi-automatic | 7,000 l/min | – |
| B2 | G 1/4"–1" | 18 bar | 20 µm | manual | 11,000 l/min | – |
| I8 | G 1/4"–1" | 18 bar | 20 µm | semi-automatic | 11,000 l/min | – |
| FUTURA | G 1/4"–1" | 12 / 16 bar | 5 µm, 0.3 µm | semi-automatic, automatic | 8,000 l/min | some versions |
| A1X | G 1/4", 1/2", 1" | 30 / 60 bar | 5 µm | semi-automatic | 9,600 l/min | – |
On FUTURA, there is a 5 µm filter and a 0.3 µm pre-filter; the activated carbon filter is not rated by particle size but by residual oil of 0.005 mg/m³. On FUTURA, the 12 bar inlet applies to the smallest size 0, which is not for use in potentially explosive atmospheres. On A1X, the G 1/4" thread withstands 30 bar, the larger threads 60 bar; the manufacturer states the flow with a 40 µm element, and with the 5 µm element fitted as standard it is lower.
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How the filter works

In the bowl, the air is first set spinning. Centrifugal force throws water droplets and coarse dirt against the wall, and they run down to the bottom of the bowl. The air then passes through the filter element, which traps particles larger than its rating.
The filter separates water that has already condensed. It does not trap water vapour — dry air throughout the air line is provided by a compressed air dryer.
A finer element traps smaller particles but restricts the flow more and clogs faster. For tools, 20 µm is enough; fit a fine element where the consumer really needs it.
In which order to place the filters

In the direction of air flow, the 5 µm filter comes first, followed by the 0.3 µm pre-filter, the 0.01 µm microfilter and finally the activated carbon filter. Each stage protects the finer one after it. If you load a fine element with coarse dirt, it clogs quickly.
You do not have to use all the stages. For ordinary tools, a 5 or 20 µm filter on its own is usually enough. Where you need very clean air, add a pre-filter and a 0.01 µm microfilter, and where odour is a problem, an activated carbon filter. It traps odours and oil vapours, not water, and does not drain condensate.
The pre-filter and the activated carbon filter are only in the FUTURA range. In the B2 range, the microfilter goes directly after the 20 µm filter.
How to choose a filter
By fineness. A 5 µm element (A2, FUTURA, A1X) traps finer particles than a 20 µm element (P2, I3, B2, I8). For I3 and I8 filters, there is also a finer 5 µm element as a spare part.
By air line pressure. Up to 10 bar, A2 is enough; the plastic P2 and I3 withstand 12 and 13 bar. For 18 bar, there are the metal B2 and I8, FUTURA is rated for 16 bar and the stainless steel A1X for up to 60 bar.
By condensate drain. You open the manual drain (P2, B2) yourself. The semi-automatic drain releases the condensate when the pressure in the bowl drops, for example after the supply is shut off. For continuous operation, FUTURA has an automatic drain, and for B2 filters there is the float condensate drain.
By environment. For potentially explosive atmospheres, there are FUTURA filters in sizes 1, 2 and 4. Where aluminium or plastic would corrode, there is A1X with a stainless steel body and bowl. I8 filters also have a metal bowl; on FUTURA you select it as a variant.
By purity class. The unit filter cleans the air at the point of use. For a higher purity class according to ISO 8573-1 throughout the air line, there are industrial compressed air filters.
Mounting and maintenance
Mount the filter upright, bowl down, and in the direction of the arrow on the body. If you need a regulator after it anyway, choose a pressure regulator with filter straight away — it saves space and one joint.
Do not let the condensate rise to the element, otherwise the air carries it on into the air line. You can tell a clogged element by the pressure after the filter dropping noticeably while air is drawn; depressurise the filter before replacing it. You will find elements and bowls among the spare parts and accessories. Clean plastic polycarbonate bowls only with a damp cloth; solvents damage them.
Where to go next
| Related pages | |
|---|---|
| Where next | What you will find there |
| Microfilters for air treatment units | 0.01 µm filtration for very clean air, after a filter or pre-filter. |
| Pressure regulators with filter | Filter and regulator in one body from 7 ranges. |
| Pressure regulators for air treatment units | Separate regulators that go after the filter. |
| FUTURA filters, pre-filters and microfilters | Size tables, optimum flows and spare elements. |
| Industrial compressed air filters | Filtration of the entire air line to a higher purity class according to ISO 8573-1. |
| Compressor intake filters | Filters for the air the compressor draws in, not for compressed air in the air line. |
Ventilek’s tip
A fine filter without a coarser stage before it clogs quickly. A coarser filter goes before the microfilter: in the B2 range a 20 µm filter, in the FUTURA range a 5 µm filter and a 0.3 µm pre-filter. Each element then only traps what it is designed for and lasts longer.
- How finely do the filters clean?
- Depending on the range, with a 5 µm element (A2, FUTURA, A1X) or a 20 µm element (P2, I3, B2, I8). FUTURA also has a 0.3 µm pre-filter and an activated carbon filter; for very clean air, there is the 0.01 µm microfilter.
- Does the filter remove water from the air?
- It separates water that has already condensed, and the condensate collects in the bowl. It does not trap water vapour; dry air throughout the air line is provided by a dryer.
- Is this a compressor intake filter?
- No. An intake filter cleans the air that the compressor draws in. The air treatment unit filter cleans the compressed air in the air line, before the regulator and the tools.
- How is the condensate drained?
- On P2 and B2 manually, on I3, A2, I8 and A1X semi-automatically when the pressure in the bowl drops. FUTURA filters have a semi-automatic or automatic drain; for B2 filters, there is a float drain.
- Does the activated carbon filter remove water?
- No. It traps odours and oil vapours and does not drain condensate. A 5 µm filter, a pre-filter and a microfilter go before it.
- Which filter is for explosive atmospheres?
- FUTURA filters in sizes 1, 2 and 4. Size 0 is not for use in potentially explosive atmospheres.
Product sorting
List of products
Metal I8 compressed air filter with a G 1" thread and a 20 µm sintered bronze element, inlet pressure up to 18 bar. Flow 11000 l/min, metal 170 cm³ bowl with sight glass and...
Metal I8 compressed air filter with a G 3/4" thread and a 20 µm sintered bronze element, inlet pressure up to 18 bar. Flow 11000 l/min, metal 170 cm³ bowl with sight glass and...
Metal I8 compressed air filter with a G 1/2" thread and a 20 µm sintered bronze element, inlet pressure up to 18 bar. Flow 4100 l/min, metal 45 cm³ bowl with sight glass and...
Metal B2 compressed air filter with a G 3/8" thread and 20 µm filtration for pressure up to 18 bar. Flow 4300 l/min, manual condensate drain that can be replaced with the B2FD...
Metal I8 compressed air filter with a G 3/8" thread and a 20 µm sintered bronze element, inlet pressure up to 18 bar. Flow 4100 l/min, metal 45 cm³ bowl with sight glass and...
Metal B2 compressed air filter with a G 1" thread and 20 µm filtration for pressure up to 18 bar. Flow 11000 l/min, manual condensate drain that can be replaced with the B2FD...
Metal I8 compressed air filter with a G 1/4" thread and a 20 µm sintered bronze element, inlet pressure up to 18 bar. Flow 1720 l/min, metal 10 cm³ bowl with sight glass and...
Compact plastic I3 compressed air filter with a G 1/4" thread and a 20 µm element, inlet pressure up to 13 bar. Flow 1200 l/min, transparent 16 cm³ bowl with semi-automatic...
A2 compressed air filter with a G 1" thread and a 5 µm sintered bronze element. Inlet pressure up to 10 bar, flow 7000 l/min, 130 cm³ polycarbonate bowl with semi-automatic...
Miniature plastic compressed air filter with a G 1/4" thread for pressure up to 12 bar. Filter rating 20 µm, flow 1200 l/min, 16 cm³ bowl with manual condensate drain.
A2 compressed air filter with a G 1/4" thread and a 5 µm sintered bronze element. Inlet pressure up to 10 bar, flow 750 l/min, 15 cm³ polycarbonate bowl with semi-automatic...
A2 compressed air filter with a G 3/8" thread and a 5 µm sintered bronze element. Inlet pressure up to 10 bar, flow 1500 l/min, 20 cm³ polycarbonate bowl with semi-automatic...
Compact plastic I3 compressed air filter with a G 1/8" thread and a 20 µm element, inlet pressure up to 13 bar. Flow 1200 l/min, transparent 16 cm³ bowl with semi-automatic...
Metal B2 compressed air filter with a G 1/4" thread and 20 µm filtration for pressure up to 18 bar. Flow 1750 l/min, manual condensate drain that can be replaced with the B2FD...
Activated carbon filter FUTURA FA34-F, size 4: G 3/4" thread, residual oil 0.005 mg/m³, flow 2,500 l/min, inlet pressure up to 16 bar, for ATEX environments.
Activated carbon filter FUTURA FA12-F, size 2: G 1/2" thread, residual oil 0.005 mg/m³, flow 1,700 l/min, inlet pressure up to 16 bar, for ATEX environments.
Activated carbon filter FUTURA FA382-F, size 2: G 3/8" thread, residual oil 0.005 mg/m³, flow 1,700 l/min, inlet pressure up to 16 bar, for ATEX environments.
A2 compressed air filter with a G 1/2" thread and a 5 µm sintered bronze element. Inlet pressure up to 10 bar, flow 4000 l/min, 45 cm³ polycarbonate bowl with semi-automatic...
Metal B2 compressed air filter with a G 1/2" thread and 20 µm filtration for pressure up to 18 bar. Flow 4300 l/min, manual condensate drain that can be replaced with the B2FD...
Metal B2 compressed air filter with a G 3/4" thread and 20 µm filtration for pressure up to 18 bar. Flow 11000 l/min, manual condensate drain that can be replaced with the B2FD...
Stainless steel filter with a 5 µm element and a 200 cm³ bowl, G 1", inlet up to 60 bar, semi-automatic condensate drain. Mounting bracket included.
Stainless steel filter with a 5 µm element and a 110 cm³ bowl, G 1/2", inlet up to 60 bar, semi-automatic condensate drain. Mounting bracket included.