Coalescing filter

The sourcebook (third edition) recommends a coalescing-type filter before a desiccant dryer to prevent fouling of the desiccant bed, and names it, or an air/lubricant separator, as the means of removing the lubricant aerosols left after the sump/separator of a lubricant-injected rotary screw compressor. WHO’s Foundations of medical oxygen systems (2023) shows a 0.1 micron coalescing filter in the filtration assembly of a typical PSA plant. NHS England guidance, HTM 02-01 (2026), asks for electrically operated automatic drainage traps on coalescing filters, as on after-coolers, receivers and separators.

For hospital technical air, the Portuguese ACSS ET 08/2010 (V.2025) puts a coalescing filter immediately before each dryer, typically filtering particles down to 1 µm, and a high efficiency coalescing filter after the dryer and dry receiver, with a particle removal efficiency of 0.01 µm and oil penetration below 0.01 mg/m³. It notes that oil-free compressors can remove the need for high efficiency coalescing filters for oil removal.

In Ultra Controlo equipment, the ULTRADRY adsorption dryer has a coalescing filter at the inlet, and the ULTRAMED treatment station has a high efficiency coalescing filter for removing water, oil and aerosols.