Type / N.
Rev.
Data
Page
Total pages
EW095.605
5
November 2010
10
96
EsiWelma
s.r.l.
The UR.40.. detectors come in four models (E, S, I, L) and their use depends on the protection
mode required:
Application
Protection mode
Part number
Group II
Category 2G
Ex d IIC T6
T
AMB
: -20
+50
UR.40.
E
Classified (hazardous)
areas
(ATEX certification
required)
Group II
Category 3G
Ex nA d IIC T6
T
AMB
: -20
+50
UR.40.
S
Heavy-duty applications
Construction conforming to
Ex d requirements
IP65
UR.40.
I
Unclassified (non-
hazardous) areas
(ATEX certification not
required)
Standard applications
Construction conforming to
Ex nA requirements
IP55
UR.40.
L
Tab.2.1 – Gas sensors: available models
In turn, each model (E, S, I, L) has two possible executions:
•
with Standard sensor
(code S: UR.20S.; UR.40S.)
•
with Professional sensor
(code P: UR.20P.; UR40P.)
Two types of sensors are commonly used for the gases that most frequently require detection
(methane, LPG, gasoline vapours, carbon monoxide etc.): catalytic (Pellistor) and
electrochemical cell. In both cases, the Professional execution is differentiated from the
Standard execution by the use of sensors that are based on the same operating principle as
the others but that over time have more measurement stability and higher poison resistance to
interfering gases.
As you can see in the table below, the part number includes several fields for rapid
identification in order to facilitate the choice of the detector according to the technical features
described above:
