For this, the tanks are purged with an inert gas, such as nitrogen, and an oxygen analyzer is used to check for trace oxygen levels in the purged tank. Depending on the type of vessel, the maintenance crews will need to be able to detect oxygen levels from 1000 ppm down to 50 ppm.
Portable oxygen analyzers, such as the GPR-1100 from Analytical Industries Inc. (AII), are the preferred tools used for this purpose. They are light-weight so easily carried to the point of use, need little power to operate (the GPR-1100 operates with the pump on continuously for up to 8 hours on a single battery charge) and will measure down to less than 10 ppm O2. Users like the simple and intuitive operation paired with a robust casing which prevents accidental damage in a heavy industrial environment.
To maximise the lifetime of the sensor, the GPR-1100 is available with quick-connect fittings to protect the sensor from ambient air when not in use, and users can expect sensors to last up to 24 months. Replacement sensors are easily available to buy and simple to fit.
A range of sample conditioning options are available for filtration, pressure reduction and flow control. As not all tanks have pressures positive enough to generate a flow to the analyzer, the GPR-1100 can be supplied with an internal pump.
The instrument is available with full ATEX certification for use in hazardous areas.