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Compressed air treatment

Clean, dry air from compressor to point of use

Filters, dryers, adsorbers and condensate treatment for air quality to ISO 8573-1. We offer the ranges of three brands – Donaldson, CompAir and MTA – and choose the best solution for each compressor room.

Choose your air qualitySend an enquiry
Donaldson filters, housings and filter elements for compressed air, steam and liquids
Highest ISO 8573-1 class
1:1:1
Pressure dew point with adsorption
−70°C
Residual oil with activated carbon
0.003mg/m³
Flow of SG filter housings
38,400m³/h

Air treatment | Brands01

Donaldson, CompAir and MTA

Three brands that complement each other. We choose the solution by flow, required air quality and your compressor room.

DonaldsonFilters and dryers

The whole air treatment chain

Donaldson has developed filter media, housings and systems since 1915. For compressed air it covers the whole chain: filters, refrigeration, membrane and adsorption dryers, oil vapour adsorbers, breathing air, sterile filtration and condensate treatment.

  • Filter performance validated to ISO 12500-1, -2 and -3
  • LifeTec™ sterile filtration of air, steam and liquids
  • Replacement elements for other manufacturers' filters too
12series with their own pageDonaldson range →
CompAirRefrigeration and adsorption dryers

Dryers matched to the compressors

CD, CD-VS, CDF-ES, CDF HP and CMT refrigeration dryers and AXM, AX and AHB adsorption dryers, matched to CompAir compressors.

  • CD-VS variable speed for lower energy use
  • CMT for a −20 °C pressure dew point
  • Adsorption dryers down to −70 °C, AHB with heated blower regeneration
8series with their own pageCompAir series →
MTADryers and aftercoolers

Thermal mass dryers

Italian DE-X, DE ETM and modular ETM DM refrigeration dryers, HPDry high-pressure dryers and CoolPro aftercoolers.

  • Thermal mass and DDF match energy use to the actual load
  • Modular ETM DM system up to 540 m³/min
  • HPDry high-pressure dryers up to 50 bar
5series with their own pageMTA series →

Air treatment | Donaldson range02

Filtration and drying for every point in the network

The range is grouped as in the Donaldson catalogue. Series with their own page link to the details; for the others we prepare a quote.

Compressed air filters

Ultra-Filter DF with UltraPleat™ elements removes particles, oil aerosols and vapours at low pressure drop. Housings are protected against corrosion and the element is changed with a bayonet fitting.

Compressed air filters
Ultra-Filter DF

Ultra-Filter DF

Main filter for compressor rooms and points of use, with a digital differential pressure gauge (Economizer).

  • 35–1,450 m³/h
  • ISO 12500-1/-2/-3
  • Suitable for indirect food contact (1935/2004/EC)
Enquire →
DF-T

DF-T

Three filtration stages in one element: coalescing filter, activated carbon and particulate filter.

  • Up to 110 m³/h at 7 bar
  • Up to 60% less space than three housings
Enquire →

DF-C

Cyclone separator that removes water, oil droplets and coarse particles before the air reaches the filters.

  • Low pressure drop
  • Superplus version with UFM-D drain
Enquire →
SG / SG-C

SG / SG-C

Flanged filter housings and cyclone separators for large flows.

  • 1,080–38,400 m³/h
  • Up to 16 bar
  • ATEX version
Enquire →

HD

High-pressure filter housings for compressed air and technical gases.

  • 20–400 bar
Enquire →
UltraPleat™

UltraPleat™

Prefilters, fine filters and activated carbon elements, plus replacement elements for other manufacturers' filters, available from stock.

  • Lower pressure drop
  • Longer service life
  • Silicone-free versions for paint shops
Enquire →
Not sure which filter or dryer you need? Send us the flow, pressure and application and we will select it for you.

Air treatment | Air quality03

What air do you need? Choose and see the chain.

Examples based on the Donaldson air treatment diagram. For each application we show the equipment sequence and the ISO 8573-1 class it achieves.

Pre-treatment in the compressor room

  1. Compressor
  2. UFK-WWater-cooled aftercooler
  3. DF-CCyclone separator
  4. Air receiver

Treatment for the selected application

  1. DF-VCoalescing prefilter
  2. BuranRefrigeration dryer
  3. DF-MCoalescing fine filter

Condensate

  1. UFM-DCondensate drain
  2. Ultrasep USOil/water separator

Result

ISO 8573-12:4:2

Pressure dew point≤ +3 °C
Oil≤ 0.1 mg/m³

These are typical configurations. We make the final selection based on flow, pressure, ambient temperature and the points of use.

Air treatment | ISO 8573-104

How to read a quality class

The designation 1:4:1 gives three classes in order: solid particles, water and oil. A lower number means cleaner air.

ClassSolid particles – maximum number per m³Pressure dew point °COil mg/m³
0,1–0,5 µm0,5–1 µm1–5 µm
0Specified per application, stricter than class 1
120,00040010≤ −70≤ 0.01
2400,0006,000100≤ −40≤ 0.1
3–90,0001,000≤ −20≤ 1
4––10,000≤ +3≤ 5
5––100,000≤ +7> 5

– = not specified

Example: 1:4:1

  1. Particles – class 1: max. 10 particles of 1–5 µm per m³
  2. Water – class 4: pressure dew point ≤ +3 °C (refrigeration dryer)
  3. Oil – class 1: ≤ 0.01 mg/m³ (≤ 0.003 with the DF-T filter)

Air treatment | Choosing a dryer05

Refrigeration, membrane or adsorption?

The pressure dew point determines the technology. Flow and operating hours determine which solution is cheapest to run.

Refrigeration dryer

Buran, Boreas, Bora · CompAir CD · MTA DE

+3 °C

Flow (Donaldson)
20–21,000 m³/h
Best for
General industry where pipework is not exposed to frost

Membrane dryer

VarioDry SPN

down to −40 °C

Flow (Donaldson)
3–63 m³/h
Best for
Individual points of use, laboratories, no electricity

Heatless adsorption

Ultrapac Smart, Ultrapac HL · CompAir AX, AXM

−40 / −70 °C

Flow (Donaldson)
5–1,000 m³/h
Best for
Small and medium flows, very dry air

Heat-regenerated adsorption

Ultradryer HRE+, HRS+, HRS-L+ · CompAir AHB

down to −70 °C

Flow (Donaldson)
larger flows
Best for
Large compressor rooms, where regeneration without air loss pays back quickly
AXM

AXM

Modular heatless adsorption dryers for efficient drying and purification of compressed air, suitable for compressor rooms or point-of-use installation.

AdsorptionHeatless4 – 14 bar g
More
Oilfreepac SMART OFP

Oilfreepac SMART OFP

Adsorption dryer for lower flow rates with a very low pressure dew point and compact design for compressed air or nitrogen.

AdsorptionHeatless4 – 14 bar g
More
Ultrapac Smart

Ultrapac Smart

Compact heatless adsorption dryer for stable compressed air drying at lower flow rates.

AdsorptionHeatless4 – 16 bar g
More
Ultrasorp Smart AKC

Ultrasorp Smart AKC

Activated carbon adsorber for removing oil vapors at lower flow rates and achieving very high air quality.

AdsorberActivated carbon4 – 16 bar g
More
DE-X

DE-X

Compact refrigeration dryers for small and medium-sized systems with a dew point of 3 °C or 7 °C and low energy consumption.

RefrigerationNon-cycling16 – 16 bar g
More
CD

CD

Continuous-operation refrigeration dryers for efficient compressed air treatment with a +3 °C dew point and low environmental impact.

RefrigerationNon-cycling16 – 16 bar g
More
Buran

Buran

Compact refrigeration dryers with integrated filtration, automatic condensate drain and reliable +3 °C dew point.

RefrigerationNon-cycling16 – 16 bar g
More
CDF-ES

CDF-ES

Cycling refrigeration dryers with energy-efficient operation and a stable +3 °C pressure dew point.

RefrigerationCycling16 – 16 bar g
More
HPDry

HPDry

High-pressure refrigeration dryers for systems up to 50 barg, suitable for industrial and process applications with higher pressures.

RefrigerationHigh pressure50 – 50 bar g
More
Bora

Bora

High-pressure refrigeration dryers for compressed air at higher pressures, available in air-cooled or water-cooled versions.

RefrigerationHigh pressure45 – 50 bar g
More
CDF HP

CDF HP

High-pressure refrigeration dryers for applications up to 45 bar with a +3 °C dew point and robust design.

RefrigerationHigh pressure45 – 45 bar g
More
CMT

CMT

Sub-zero refrigeration dryers with dew points down to -20 °C, combining the low operating costs of a refrigeration dryer with the performance of regenerative drying.

RefrigerationSub-zero
More

Air treatment | CompAir and MTA06

CompAir and MTA dryers

CompAir and MTA series, each with its own page and technical data.

Air treatment | Industries07

Where air quality is part of the product

Compressed air often touches the product or its packaging. That is why the industry and the application set the required quality.

  • Food

    Food

    Air in contact with food, free of oil and moisture

  • Beverages, wine, beer

    Beverages, wine, beer

    Sterile air, steam and liquid filtration

  • Pharmaceuticals

    Pharmaceuticals

    Dry air and validated sterile filters

  • Hospitals

    Hospitals

    Medical and breathing air

  • Electronics

    Electronics

    Very dry, particle-free air

  • Automotive

    Automotive

    Silicone-free air for paint shops

  • Paint shops

    Paint shops

    Fine air to class 1:4:1

  • Chemicals and gases

    Chemicals and gases

    High-pressure housings, ATEX, technical gases

Air treatment | Service08

Service, measurements and replacement elements

Air treatment only performs with regular maintenance. A clogged element raises the pressure drop and the compressor's energy use.

Service technician with replacement filter elements next to the service van

KOMP-R

  • Replacement of filter elements and activated carbon cartridges
  • Service of refrigeration and adsorption dryers
  • Measurement of pressure dew point, residual oil and pressure drop
  • Compressor room audit and improvement proposals
Dew point and oil measuring equipment →

Donaldson laboratory

  • Membrane integrity testing (Membra-Check)
  • Depth filter integrity testing (Filter Test Center)
  • Differential pressure measurement
  • Particle spectrum analysis for liquids
  • Test filtration of compressor condensate

Air treatment | Questions09

Frequently asked questions about air treatment

Why is compressed air treatment important?

Untreated compressed air contains moisture, particles, oil and other contaminants. These corrode pipework, damage valves and pneumatic components, and can contaminate the product. Proper treatment protects your equipment and reduces rejects and downtime.

When do we choose a refrigeration dryer and when an adsorption dryer?

A refrigeration dryer is enough when a pressure dew point of +3 °C will do and the pipework is in a heated area. We choose an adsorption dryer when the process needs a dew point of −40 °C or −70 °C. This applies to pharma, food, electronics, laboratories and outdoor pipework, where condensate could freeze.

What does ISO 8573-1 class 1:4:1 mean?

The three numbers are the classes for solid particles, water and oil, in that order. With 1:4:1, particles are class 1, the dew point is ≤ +3 °C (class 4) and oil is ≤ 0.01 mg/m³ (class 1). Donaldson achieves this with a Buran refrigeration dryer, two coalescing filters and a DF-T three-stage filter.

What is the pressure dew point?

It is the temperature at which water vapour in compressed air starts to condense at working pressure. A lower dew point means drier air. The dew point must be below the lowest temperature the pipework is exposed to.

Why does filter pressure drop matter?

The compressor must make up every bar of pressure drop with a higher pressure, which means roughly 7% more energy. That is why Donaldson uses UltraPleat™ elements with a lower differential pressure, and the Economizer gauge shows when the element is due for replacement.

Can Donaldson elements be fitted in other manufacturers' housings?

Yes. Donaldson stocks replacement elements for the filter housings of most other manufacturers. Send us the part number of your current element and we will find the right replacement.

How often should filter elements be replaced?

Coalescing and particulate filters are usually replaced once a year or when the differential pressure reaches its limit. Activated carbon is replaced based on operating hours and inlet oil concentration. On dryers we regularly check the dew point and condensate drainage.

What information do you need for a quote?

Flow (m³/min or m³/h), working pressure, the required ISO 8573-1 quality or dew point, ambient and inlet air temperature, compressor type (oil-lubricated or oil-free) and the application. A diagram of the compressor room and any measurements also help.

Air treatment

Describe your compressed air system and we will propose the right solution.

Fill in a short form and we will prepare an optimal solution for cooling, drying, filtration, and condensate removal.

Improved air quality
Condensate removal optimization
Complete system solution
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