IREX is a sinter-free, fully featured infrared gas detector that produces a mV Wheatstone Bridge output as used on conventional pellistor based systems. IREX replaces old pellistor heads by simply mounting on the original junction box, and connecting to the original cable. The IREX concept enables upgrade to dual-wavelength IR gas detector technology without incurring the very significant costs associated with replacing the control system and re-installation.
The problem with pellistors
Pellistors (or Catalytic Beads) have been the flammable gas sensor of choice for oil and gas applications and general industry. Pellistors do however have several technical limitations:
They do not fail safe: pellistors are easily poisoned by substances such as silicones, sulphur and lead, rendering them insensitive to gas. Pellistors must be operated behind a sinter (flame arrestor): which may become blocked; thus preventing gas from reaching the sensor. Pellistors are high maintenance: sensors must be regularly tested with gas to ensure they are operational. Pellistors typically last 3-5 years only. Pellistors may burn-out if exposed to flammable gas concentrations above 100% LEL. Pellistors need oxygen to be present to work; their efficiency reduces in oxygen deficient environments. IREX overcomes all of these issues, and delivers highly dependable and rapid gas detection with no un-revealed failures.