A gas analysis system began experiencing recurring contamination symptoms, including unstable readings, poor response, and increasing maintenance demand. Inspection suggested that process contamination was travelling further into the sample path than intended.
The problem persisted despite repeated cleaning.
Observed effects
Filters and sample components showed evidence of contamination build-up, and the measurement quality declined progressively rather than failing all at once. Certain process conditions made the behaviour worse, indicating that the contamination source was dynamic rather than constant.
The sample path had become part of the problem.
Investigation direction
The review focused on whether glycol carryover from the process was entering the sampling system and then collecting in regulators, filters, or low points. Sample transport design and drainage effectiveness were also reviewed.
The contamination pattern matched a recurring carryover mechanism.
Likely cause
The main issue was consistent with glycol contamination entering the sample system and degrading measurement reliability over time. Once contamination entered the transport path, it affected both cleanliness and sample representativeness.
The analyser symptoms were downstream consequences of an upstream contamination problem.
Practical lesson
Where glycol carryover is possible, the sample design must control for it explicitly through filtration, drainage, phase management, and maintainable inspection points. Repeated cleaning without design review rarely gives lasting improvement.
Contamination control is a design decision as much as a maintenance task.
