Medical air
What does an activated carbon tower do in compressed air?
What does an activated carbon tower remove from compressed air, and where is it installed?
Short answer
An activated carbon tower removes oil vapours and other hydrocarbons from compressed air by adsorption on a bed of activated carbon; the ULTRAK datasheet calls for a coalescing filter upstream and recommends a dust filter downstream to catch carbon residue.
Air treatment works in stages. In the ULTRAMED treatment unit, for example, a coalescing filter first removes water, oil, aerosols and particles, and an activated carbon filter then removes oil vapour and odours. An ULTRAK activated carbon tower is a dedicated stage for oil vapour: flow distributors spread the air evenly through a bed of activated carbon, and the oil vapours and other hydrocarbons are separated by adsorption, a dry separation.
Where it is installed
- After a coalescing filter: the ULTRAK datasheet says one is required upstream.
- Before a dust filter: a 1 μm dust filter is recommended downstream to intercept any residue from the activated carbon.
- In medical air plants, HTM 02-01 (2026) lists a carbon filter among the typical filters of the dryer system, together with water and oil filters, two desiccant columns, a dust filter and a bacteria filter.
ULTRAK figures
| Parameter | ULTRAK datasheet value |
|---|---|
| Residual oil vapour content (nominal) | < 0.003 mg/m³ |
| ISO 8573-1 quality class, oils | 0/1 |
| Operating pressure | 16 bar |
| Operating temperature | 1.5 to 45 °C |
| Flow range | 6 to 6,500 Nm³/h |
| Pressure drop, new and dry | 20 mbar (0.29 psi) |
The datasheet gives an ISO 8573-1 class only for oil; the classes for solids and water are left blank.
In Ultra Controlo medical air treatment, the ULTRAMED unit includes a high efficiency activated carbon filter that reduces oil vapour and odours down to 0.003 mg/m³.
More questions
Does an oil-free compressor still need a carbon filter?
HTM 02-01 says oil-free compressors reduce filtration requirements, but its typical medical air dryer system still includes a carbon filter.
Why is a filter needed after the carbon tower?
The ULTRAK datasheet recommends a 1 μm dust filter downstream to intercept any residue from the activated carbon.
Sources
- ULTRAK datasheet, p. 2
- ULTRAMED datasheet, p. 3
- NHS England, HTM 02-01 Medical gas pipeline systems (2026), Part A, 7.34 and 7.64
Ultra Controlo figures come from its technical datasheets. Third-party facts were read at the source on the date shown.