An oxygen analyser is used to monitor and control mixture to ensure that hazardous situations do not arise. If the oxygen level is detected as being above the control point, action must be taken within 30 seconds.

Tulsa USA based environmental protection specialist Callidus Technologies Ltd has recently purchased two systems utilising two Servomex 1900 oxygen analysers and a sampling system meeting the strict US Coast Guard requirements for monitoring ships being loaded with volatile liquids at marine terminals. Because of the safety critical nature of this application, two oxygen analysers are used in a redundant voting arrangement.

Servomex 1900 magnetodynamic (suspension type) paramagnetic analysers with a custom designed and manufactured sampling system are approved for use in hazardous area classification Class 1 Division 2 Groups C and D. Piping to the two analysers was designed to be of equal length from the sample take-off and the sampling system was configured so that the analysers could be calibrated concurrently, with only a single control point for the gas inlet for calibration and sample.

Another design feature was the coalescing/membrane filter that is installed in such a way that it is continuously drained so that condensate does not collect. Early tests with the Servomex system showed that response time was in the order of five seconds, and the two analysers could easily read within 1% of the measured range.

MJ Information No: 21216