Information For Safe Use; Measuring Function For Explosion Protection Acc. To 2014/34/Eu; Operation - Dräger PEX 3000 Mode D'emploi

Operation

The PEX 3000 type XTR 0090 and XTR 0091 transmitters (remote version) are
intended to operate a remote Dräger sensing head, such as the Polytron SE Ex
PR ... DQ and HT M DQ (100 %LEL) or Polytron SE Ex LC ... DQ (10 %LEL).
As the operation of the PEX 3000 in combination with the mentioned remote
sensing heads does not really differ from the operation of the PEX 3000 with
integral sensor, it is not explicitly considered in these operating instructions.
Likewise, the operation of further housing versions, e.g. of the types XTR 0001
and XTR 0011 (drilling templates, see page 47) is not explicitly described.
The transmitters must not be operated at ambient temperatures of less than –
40 °C. For PEX 3000 type XTR 0000, XTR 0001, XTR 0010 and XTR 0011
transmitters, the upper maximum permitted temperature depends on the
temperature class. For the T6 temperature class, this is 40 °C, or 55 °C for T5
and 65 °C for T4. For PEX 3000 type XTR 0090 and XTR 0091 transmitters, the
upper maximum permissible temperature is generally 65 °C.
The transmitter is approved for device categories II 2G and II 2D and can be
installed in zones 1 or 2 and in zones 21 or 22. Observe the installation
instructions.
Not to be used in oxygen-enriched atmospheres. In conjunction with a suitable
controller with pre-adjusted alarm thresholds, acoustic or optical alarm devices
can be activated or automatic countermeasures introduced before the detected
gases or vapours can form dangerous flammable concentrations with air.
3.3

Information for safe use

Only certified sensors or remote sensing heads are allowed to be connected to
the transmitter's br/br, ge/yw and sw/bk connection terminals.
WARNING
In gas explosion-hazard areas (zones 1 and 2) the transmitter's cover is only
permitted to be opened for maintenance purposes.
WARNING
In dust explosion-hazard areas (zones 21 and 22) there is no dust explosion
protection if the housing cover is opened in a live state. The Ex area has to be
temporarily de-classified, if necessary! Appropriate precautions must be made.
Before closing the cover, ensure that the transmitter is free of dust.
Observe the following instructions for the measuring function:
1. The heat of reaction measuring principle, which is based on the catalytic
oxidation of a combustible gas, is essentially ambiguous because, at high
measuring gas concentrations, there is not enough oxygen in the sensor to
oxidise the combustible gas. As a result, the measuring signal decreases at
high gas concentrations and can lead to values within the measuring range.
The downstream controller must be operated with alarm devices and
measured value outputs (if present) as well as alarm outputs, which are
latching if the measuring range is exceeded.
2. The heat of reaction measuring principle requires a minimum oxygen
concentration of 12 % vol., otherwise the displayed measuring values will be
too low because of oxygen deficiency.
3.4 Measuring function for explosion protection
acc. to 2014/34/EU
The PEX 3000 transmitter type XTR 000x and remote versions XTR 009x in
combination with the Polytron SE Ex PR ... DQ sensing head were certified for
the explosion protection for the following gases and vapours pursuant to EN
60079-29-1 with regard to the measuring function: acetone, acetylene,
ammonia, petrol 065/095 (FAM regular petrol), benzene, 1.3-butadiene, n-
butane, n-butyl acetate, diethyl ether, dimethyl ether, ethanol, ethene
(ethylene), ethyl acetate, ethylene oxide, n-hexane, methane, methanol, methyl
ethyl ketone (MEK), methyl methacrylate, n-nonane, n-octane, n-pentane,
propane, i-propanol, propene (propylene), propylene oxide, toluene, hydrogen
and o-xylene.
4 Operation
Although the transmitter was factory-tested before delivery, the
commissioning after installation must include the zero-point and span
calibration. The commissioning process must be concluded with a functional
test of the complete gas detection system.
Dräger PEX 3000