The hidden dangers of varnish buildup in Rotary Screw Air Compressors

Oil-flooded rotary screw air compressors (RSACs) are vital pieces of equipment in many industries. They provide a reliable source of compressed air for everything from powering tools to driving industrial processes. However, even the most robust machines can be brought down by varnish buildup.

RSACs use a pair of intermeshing rotors to trap and compress air. To function properly, they rely on a constant stream of oil for lubrication, sealing, and cooling. This oil circulates throughout the system, keeping everything running smoothly.

Varnish is an unfortunate byproduct of oil degradation. It's not a single substance, but rather a collection of sludge, deposits, and sticky residue that forms as the oil breaks down. This breakdown can be triggered by several factors, including:

• Excessive heat - the high temperatures inside an RSAC can accelerate oil oxidation, leading to varnish formation.
• Dirt, rust, and other contaminants can enter the system and mix with the oil. These impurities act as catalysts for varnish formation.
• Extending and/or skipping oil changes and filter replacements allows contaminants to build up and accelerates oil degradation.

Varnish may seem harmless at first, but it can have a devastating impact on your RSAC. Varnish deposits on heat exchangers can hinder their ability to dissipate heat, which may cause the compressor to overheat, leading to premature wear and tear. Finally, varnish can also clog valves and other critical components, causing malfunctions and in the worst-case scenario, complete compressor shutdown.

Understanding the causes and consequences of varnish, allows you to take steps to minimise its impact on your equipment. This includes using high-quality solutions, such as Texaco’s VARTECH^® technology, which aims to help tackle varnish from multiple angles with a two-step process designed to help promote long-term system cleanliness. The first step utilises VARTECH Industrial System Cleaner, which works to remove existing varnish deposits and prepare the system for fresh oil. Step 2, introduce one of Texaco's premium compressor oils, Cetus VDL, Cetus HiPerSyn or Cetus PAO. Cetus HiPerSyn and Cetus PAO are designed to offer oxidation stability, Cetus VDL features varnish deposit control technology (VDC technology) designed to deliver reduced deposit formation that helps prevent deposit build up, minimising varnish formation.

Additionally, following a proper maintenance schedule and keeping a close eye on your compressor's performance with oil analysis, such as Texaco LubeWatch, can help keep your RSAC running smoothly for years to come.