Coalescing Filters Explained: What They Do & Why You Need One

Compressed air is often contaminated with dirt, oil, and moisture—even in brand new systems. Dust enters through the compressor intake, oil carryover occurs from pistons or oil/water separators, and water vapour condenses under pressure. For industries relying on high-performance pneumatic systems, maintaining clean, dry compressed air is essential for reliability and efficiency.

The most effective way to ensure ultra-clean compressed air is to install a high-efficiency coalescing filtration system. Ultramax coalescing filters are engineered to remove 99.99% of solid and liquid particles as small as 0.01 micron, delivering exceptionally pure compressed air with minimal maintenance and low operating costs.

Engineered for High Performance and Reliability

At the core of every Ultramax coalescing filter is a disposable filter element made from borosilicate microfibre and a fluorocarbon binder. These filter elements can withstand temperatures up to 120°C and feature a dual-layer structure: a fine inner layer for particle capture and an outer drainage layer to remove condensed liquids like water and oil.

Captured liquid droplets remain mobile within the media, growing in size as they travel along the microfibres. These coalesced droplets are efficiently transferred to the drainage layer and directed into the filter bowl for removal.

Smart Design for Low Maintenance

Ultramax compressed air filter elements are self-supporting and twist directly onto the housing’s tie rod. This eliminates the need for extra parts like end caps or gaskets. When it’s time to replace the filter, only the filter material is discarded—keeping both waste and costs low.

Designed with efficiency in mind, these filters start with a low pressure drop of less than 0.15 bar. Over time, as particles accumulate, the pressure increases gradually. When it reaches 0.7 bar, a differential pressure indicator can alert users that it's time to change the filter element—ensuring consistent airflow without compromising system performance.

Effective Removal of Oil, Water, and Aerosols

Coalescing filters are essential for removing water, oil, and other liquid aerosols from compressed air and gas lines. Ultramax filters use a proprietary coalescing media with gradient density and a specialised surface structure to ensure maximum separation efficiency in all industrial applications.

Whether you're protecting air tools, valves, or critical manufacturing equipment, a properly designed coalescing filtration system is a cost-effective investment in clean, reliable compressed air.