IREX0 pages

CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C2H4
C2H5OH
C3H6
LPG
Pellistor Replacement IR
Gas Detector
• Pellistors do not fail safe: sensors can
be ‘poisoned’ and rendered insensitive
to gas by silicones, lead, sulphurs and
chlorinated compounds.
• Pellistors must be operated behind
a sinter (flame arrestor): which may
become blocked, thus preventing gas
from reaching the sensor.
• Pellistors may burn-out: if exposed to
gas concentrations in excess of 110%LEL.
• Pellistors are high-maintenance:
sensors must be regularly tested with
gas to ensure they are still operational.
Sensors typically last 3-5 years, after
which they must be exchanged.
• Pellistors need oxygen: their ability
to detect gas reduces significantly in
oxygen deficient atmospheres.
IREX is an innovative infrared (IR) flammable gas detector designed
specifically to directly replace pellistor (catalytic bead) type flammable
gas detectors. IREX operates from control systems designed solely for use
with pellistor-based gas detectors: it produces a mV Wheatsone Bridge
type signal (as per a pellistor) and operates from as little as 2.9Vdc. IREX
is supplied with an M20 type fixing enabling originally installed detector
junction boxes and cables to be retained.
IR Technology versus Pellistor Gas Sensors
Pellistor sensor technology has provided effective flammable gas
detection at low cost for many years. Pellistors do however have several
disadvantages:
IREX
All of these issues are overcome using IREX.