How to handle gumming in air compressors?

First, assess the degree and location of gelation.

When gelation occurs in an air compressor, avoid disassembling the unit prematurely. Instead, consider accompanying symptoms such as darkening oil color, rising filter differential pressure, elevated discharge temperature, and reduced oil‑line flow to make a preliminary assessment of whether the gelation is occurring in the lubricating oil, oil filter, cooler, or oil‑gas separator. If only mild oil degradation is present, the usual approach is to replace the oil and filters with compliant products. However, if noticeable viscous deposits or blockages have already formed, thorough cleaning of the oil circuit and inspection of the relevant components are required.

Common causes of gelation

• Oil oxidation or use beyond its recommended service life:Lubricating oil, when operated at high temperatures over an extended period, tends to gradually thicken and form varnish.
• Operating temperature is too high:Poor heat dissipation, insufficient airflow, or diminished cooling performance can accelerate oil degradation.
• Impurity contamination:The ingress of dust, moisture, metal chips, or other contaminants into the oil system may accelerate the formation of sludge and varnish.
• Mixing different types of oil:Mixing lubricants of different formulations or from different batches may reduce stability and increase the risk of gumming.

Prudent handling procedures

• Shutdown and depressurization:Before performing any work, the equipment must be shut down, de-energized, and depressurized. Only proceed after confirming that there is no residual pressure in the system.
• Drain the old oil:Drain the old oil when the oil temperature is moderate to help remove some suspended impurities; if the oil has clearly gelled, record its discharge condition.
• Replacing the filter element and seals:It is recommended to inspect the oil filter, oil separator element, and aged seals together, and replace them as necessary to prevent residual contaminants from continuing to affect the new oil.
• Cleaning the oil circuit:For mild fouling, appropriate cleaning methods may be employed in accordance with the maintenance guidelines; when gelation is severe, professional personnel should be consulted to determine whether it is necessary to disassemble and clean the cooler, piping, or valves.
• Add compliant new oil:Select lubricants that meet the equipment’s specifications, and avoid using products of unknown origin or those with mismatched specifications.
• Trial Operation Observations:After replacement, monitor oil pressure, temperature, noise levels, and the filter element differential pressure; only proceed to normal operating conditions once no abnormalities are detected.

Precautions during cleaning

Cleaning is not always better when it’s more aggressive. Overly harsh cleaning methods can damage sealing materials or leave residual cleaning agents, which may compromise subsequent operation. The chosen approach should be gentle, thoroughly removable, and compatible with the lubricant, tailored to the extent of gel formation. If the equipment is still in a critical production phase, it is advisable to first develop a comprehensive plan for shutdown, cleaning, acceptance testing, and standby procedures, thereby preventing hasty interventions that could lead to secondary failures.

How to reduce re-gelling

• Inspect the lubricant condition according to the maintenance schedule; do not assume that “it can still run” means it does not need to be replaced.
• Keep the cooling system clean and monitor the condition of the heat sinks, air ducts, and coolant.
• Control the intake air environment to minimize the ingress of dust and moisture into the system.
• Avoid mixing different types of oil indiscriminately, and when changing the oil, drain out as much of the old oil as possible.
• Establish operating records and monitor changes in exhaust temperature, oil pressure, and filter differential pressure.

Tip:If gelation has already caused significant blockage, abnormal temperatures, or frequent alarms, stop forced operation and have experienced maintenance personnel conduct an on-site assessment to prevent the fault from escalating.