Crowcon’s IREX IR flammable gas detector tested by Micropack for use offshore
Published on 15 July 2009
IR flammable gas detector rigorously tested for offshore use
Crowcon's innovative new IREX infrared (IR) pellistor-replacement flammable gas detector has been proven suitable for offshore use after undergoing testing by Micropack Engineering Ltd. The device went through rigorous performance testing by the highly respected testing authority based in Aberdeen, Scotland.
IREX is designed to replace pellistor (catalytic bead) type flammable gas detectors, resulting in faster response times and greatly reduced zero drift. Capable of detecting methane, butane, propane and many other hydrocarbons, IREX is specifically designed for applications such as offshore platforms, refineries, gas storage and distribution networks, sewage treatment plants and certain manufacturing processes (such as aerosol production).
Pellistor and some other IR type gas detectors are fitted with sinters (flame arrestors) to achieve Exd flameproof certification. Sinters slow response times significantly and can become blocked by contaminants, a frequently underestimated problem. Because IREX does not use sinters it has an extremely fast T90 response time of less than four seconds - comparable with the most expensive conventional IR gas detectors. Excellent zero stability is also achieved, with none of the drift issue associated with pellistors and cables.
Because IREX operates from the same control systems as pellistor-based detectors, it allows existing pellistor-based systems to be easily upgraded without any of the costs associated with installing a new control system. Sophisticated systems and algorithms ensure reliable operation at all times, with no adjustments necessary to the detector itself. Zero and span adjustments (if required) are performed at the control panel, and gas response tests and calibration can also be done remotely, with test gas simply applied via a tube to the standard weather cover.
IREX is designed to provide over 10 years reliable operation, and as there are no sensors which need replacing and because routine testing requirements are minimised, operating costs during its entire lifetime are minimal. The detector produces a mV Wheatstone Bridge type signal (identical to a pellistor) and operates from as little as 2.9Vdc. In addition, it is supplied with a M20 type fixing, allowing originally installed detector junction boxes and cables to be retained.
Manufactured from 316 stainless steel; IREX has both ATEX and IECEx approval and is undergoing assessment for IEC61508 SIL 2 compliance.
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