8 Gas Detection Pellistor Replacement IR Flammable Gas Detector


Crowcon’s (UK) innovative new IREX infrared (IR) flammable gas detector 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 the oil, gas and petrochemical industries.


Pellistor and some other IR type gas detectors are fitted with sinters (flame arrestors) to achieve Exd flameproof certification. Sinters slow response time significantly and can become blocked by contaminants, a frequently underestimated problem. Using an IREX detector results in a T90 response time of less than seven 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. IREX produces a mV Wheatstone Bridge type signal (identical to a pellistor) and operates from as little as 2Vdc. In addition, it is supplied with a M20 type fixing, allowing originally installed detector junction boxes and cables to be retained. Sophisticated systems and algorithms ensure reliable operation of IREX at all times, with no adjustments ever 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 is 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. Manufactured from 316 stainless steel, IREX has both ATEX and IECEx approval and is undergoing assessment for IEC61508 SIL 2 compliance.


Reader Reply Card no 35 Gas Engine Protector Never Sleeps


Rapid changes in landfill gas quality can damage the engines it powers. To keep watch, Viridor has installed static automatic gas analysis and reporting equipment supplied by Geotech (UK) at its Whitehead landfill site near Manchester. Every ten seconds the equipment measures concentrations of CH4


, CO2 and O2 and


outputs the data in three, 4-20 mA channel signals. Control circuits receive the analyser signals and are set to shut down the landfill gas (LFG) engine before damage by a fast-changing gas mix. Gas thresholds are set at three percent maximum for O2


with three


levels for methane of warning at 55 percent, maximum of 60 percent and a site-variable minimum of 30-40 percent. When reached the LFG engine is automatically shutdown and gas diverted to flare on site. Viridor Whitehead’s LFG engine’s protection is now totally dependent on its Geotech static gas


analyser set automatically to sample, analyse and report 8640 times a day, every day. The readings are data logged and provide gas output statistics available via secure Internet access for Viridor at any location where there is an Internet connection.


Describing the installation, power plant supervisor, Mark Woollams said, “Protection of our LFG engines is now totally dependent on the static gas analyser. We ran a pilot and are confident we can depend on it totally to protect our engines from damage.” To ensure gas analyser accuracy an auto-calibration system routinely purges and calibrates the equipment. The data from each auto-calibration is also collected by the data loggers enabling a full verification audit trail for all gas analysis readings and calibrations.


Reader Reply Card no 36 New Infrared Gas Transmitters


Dräger (Germany) has further extended its comprehensive range of explosion proof fixed gas detection systems with two new infrared (IR) gas transmitters. Ideal for use throughout industry and ensuring no false alarms, the Dräger PIR 7000 provides continuous monitoring of flammable gases and vapours, whilst the Dräger PIR 7200 is designed to monitor carbon dioxide.


Accurate and reliable in use, both instruments have demonstrated a precise, stable measuring performance during long-term tests and, as certified by TÜV*, only account for two percent of the SIL 2 budget for a gas detection system. Incorporating double-compensating, 4-beam technology and designed to detect methane, propane and ethylene as standard, the Dräger PIR 7000 also features a variable gas library which allows up to ten other substances such as solvents or alcohol to be added. Easily adapted to meet the requirements of different industries, the measuring ranges of both transmitters can be freely configured to suit the needs of different applications.


A special process adapter allows the transmitters’ response characteristics to be changed to meet individual requirements. The response mode can also be configured to suit particular needs with, for instance, the “high speed” option, when combined with low alarm thresholds, providing indication of detected substances in under a second. Any faults during the measuring operation are immediately shown on the status indicator. A special process adapter allows the transmitters’ response characteristics to be changed to meet individual requirements. The response mode can also be configured to suit particular needs with, for instance, the “high speed” option, when combined with low alarm thresholds, providing indication of detected substances in under a second. Any faults during the measuring operation are immediately shown on the status indicator.


Reader Reply Card no 38 October/November 2008 AET


Photovac (USA) is pleased to introduce the MicroFID flame ionization detector for landfill gas detection. The measurement of methane and non-methane components in landfill gas is essential for compliance with air quality operating permit requirements, and the MicroFID detector from Photovac offers this capability in a portable and easy to operate instrument. Featuring flame ionization detection (FID) technology, the MicroFID measures methane gas accurately and quickly. A single tutor key prompts the operator through the basic operations, and critical data is displayed in less than 3 seconds. Further, the MicroFID provides datalogging capability so readings can be stored in the instrument and downloaded to a computer for subsequent analysis and recordkeeping purposes. Non-methane hydro- carbon readings are performed with the simple addition of a snap-on charcoal filter capsule. The MicroFID meets and exceeds the requirements for EPA Federal Reference Method 21 for fugitive gas emissions.


MicroFID for Landfill Gas Detection


Reader Reply Card no 37 New Improved Gas Detection System


Stonegate Instruments (UK) has developed a new improved Gas Detection System for the air conditioning and refrigeration industry.


The new system has been carefully designed to detect a wide variety of popular refrigerants including CFCs, HCFCs and HFCs. It can accommodate up to 24 remote refrigerant sensors and uses a compact central monitor unit with flexible wiring for easy installation. In addition, both audible and visual alerts for alarm conditions and sensors can be included.


Reader Reply Card no 39


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