Coalescing Filters

Coalescing Filters for Compressed Air Systems

Coalescing filters are designed to remove fine liquid aerosols, including oil mist and water droplets, together with sub-micron contamination from compressed air. Correct filtration helps protect pneumatic equipment, improve air quality and reduce contamination reaching downstream processes.

The Tanair COF range includes complete oil-removal filter assemblies with 1/4", 1/2", 3/4" and 1" BSP connections, making it suitable for smaller point-of-use systems through to larger workshop and industrial applications.

Choose the Correct Coalescing Filter

Select the filter using the compressor's actual delivered airflow, working pressure and pipe connection. Do not choose by BSP size alone, as two systems with the same connection may have very different airflow requirements.

How a Coalescing Filter Works

Compressed air passes through a dense network of filtration fibres. Microscopic oil and water droplets collide with the media and with each other, forming larger droplets that separate from the airflow and drain into the bottom of the filter housing.

• Dense filter media captures fine liquid aerosols.
• Small droplets merge into larger droplets through coalescence.
• Separated liquid drains into the filter bowl.
• Cleaner compressed air continues to downstream equipment.
• Correct drainage helps prevent collected condensate from being carried back into the airflow.

Typical Applications

Installation and Maintenance Guidance

Coalescing filters are commonly installed after suitable upstream particulate filtration and before sensitive downstream equipment or final-use points. The exact position depends on the compressor, dryer technology and required final air quality.

Installation Checks

• Install the filter in the direction shown by the airflow arrow.
• Keep the housing upright so collected liquid can drain correctly.
• Provide sufficient clearance for bowl removal and element servicing.
• Use suitable isolation and depressurise the system before maintenance.
• Check the drain regularly and route condensate to an approved treatment system.

Why Maintenance Matters

As a filter element becomes contaminated, differential pressure rises and airflow may become restricted. This can increase compressor energy use and reduce the pressure available at the point of use.

Compressed Air Filtration Specialists

With more than 30 years of industry experience, Compressed Air Systems UK supplies coalescing filters, replacement elements, air dryers and complete compressed air treatment solutions for workshops and industrial applications across the UK.