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The Dräger X-am 7000 mobile multigas detector
is an innovative solution for the simultaneous
and continuous measurement of up
to five gases. A combination of over 25 sensors
allows flexible adaptation to individual
measurement tasks. The Dräger X-am 7000
can be equipped with three electrochemical
and two infrared-optical or catalytic sensors.
In many industrial applications, the instrument
is the ideal companion when it comes
to reliable monitoring of ambient air for the
presence of oxygen, toxic and combustible
gases and vapours.
Properties and functional principles of
the Dräger X-am 7000 sensors
All the sensors used in the Dräger X-am
7000 are "smart" – but what exactly does
that mean?
The sensors feature an integrated data memory,
in which various parameters such as
sensor type, gas type and measurement
range, temperature compensation, alarm
limits and calibration data are stored. When
a sensor is inserted into the instrument, no
configuration is necessary because all the
relevant data are automatically transmitted
from the sensor to the instrument. In other
words, the sensors function on a “plug and
play” basis. When a service technician
needs to replace a sensor or prepare the
instrument for a different application, this
can be done easily by simply inserting the
sensor. The instrument is configured automatically
and is already pre-calibrated, virtually
ruling out incorrect operation.
Properties of infrared sensors
Infrared sensors are capable of detecting
either explosive gases and vapours or CO2.
The optical sensor is characterized by an
extremely long service life (with a five year
warranty), and adjustment intervals of up to
12 months. Infrared detectors are also resistant
to sensor poisoning, and the effects
of temperature, dirt or vibration are eliminated
by the compensation detector. Accordingly,
the sensor justifiably claims to be failproof.
Unlike the catalytic EX sensor, the infrared
EX sensor can also be used to conduct
measurements in low-oxygen or zero-oxygen
conditions. Furthermore, methane, propane
and butane gases, as well as LPGs (liquefied
petroleum gases – used as fuels in the
shipping industry) can be detected not only
in the lower explosive limit (LEL) range,
but also in the percent-by-volume range.
The smart EX sensors in the X-am 7000
contain a library of different combustible
gases or vapours. Whenever one of these
substances is selected, the sensor sensitivity
is switched automatically to the respective
value of the substance in question. The
Dräger X-am 7000 also features a function
key which is used to switch between different
gas configurations at the push of a
button, making it easy and safe to adapt
the instrument to different applications.
Properties of catalytic sensors
Catalytic sensors are used to detect combustible
gases and vapours.
The SmartCat sensor in the Dräger X-am
7000 is highly sensitive to atmospheres
containing organic vapours. Since the instruments
are often adjusted to gases
which are detected with higher sensitivity,
this ensures that an alarm will be reliably given
even in explosive vapour atmospheres.
This is a very valuable attribute, particularly
in refineries or when detecting unknown hazards
(e.g. by fire brigades).
The poison-resistant design also minimizes
the effects of sensor poisons, especially
H2S. What is more, the impact-resistant
sensor can withstand even a one and a half
metre drop with hardly any noticeable impairment
of measurement function.
Properties of the electrochemical sensors
A whole series of different electrochemical
sensors is used for the detection of various
toxic gases and vapours and oxygen. Dräger's
patented three-electrode technology
maximizes the signal with respect to the
gas being measured, and minimizes the effects
of other substances.
The Dräger Sensors XS R for CO, H2S and
O2 come with a five year warranty. The XS
sensors are designed for “extra stability”,
and do not require any consumable substances.
This results in a long service life
and adjustment intervals of up to 12 months.
Even in changing ambient conditions, the
DrägerSensors perform reliable measurements.
A temperature sensor integrated
into the sensor compensates for any fluctuations
in the ambient temperature, and
the sensors are also pressure-compensated.
Power supply unit
The Dräger X-am 7000 can be used with a
3 Ah or 6 Ah power supply unit. It features
two or four batteries, which are discharged
one after another. Once each battery has
been discharged, its capacity is verified.
The display of the remaining available battery
capacity is refreshed, and therefore remains
accurate and reliable. Because the
batteries are discharged in series, an up-todate
picture of the battery capacity is obtained
at the latest after three to four days of
use, assuming shifts of >7 hours. As such,
the batteries are monitored during operation,
and defective cells are detected.
The instrument sounds a main battery
alarm and switches itself off automatically
once the minimum charge Q (standby)
is reached. This reserve is sufficient for
roughly seven standby days without recharging.
During this time, the sensors remain
warm, ensuring they are quickly ready
for use. At the end of this time, the instrument
disconnects itself from the power
supply. Nonetheless, thanks to the deep
discharge reserve the supply is still not fully
discharged. This protects the battery and
ensures a long service life. Upon recharging
of the power supply unit, the only difference
is that the sensors require longer warm-up
times.
The Dräger X-am 7000 is charged at a fairly
high charge current, namely 1 A. This allows
the power supply units to be recharged
quickly. In addition, the high charge currents
also prevent the formation of dendrites –
ageing-related crystals which can result in
battery cell damage – thus giving a longer
cell life.
The “charge intelligence” is incorporated
into the rechargeable battery and means
that the battery can also be charged without
the Dräger X-am 7000. The charger
module can be connected to the Dräger
multiple charger module, a mains plug or
a car charger unit.
Durability and protection against climatic
conditions
In industrial applications, gas detection instruments
are frequently exposed to knocks
and harsh climatic conditions. The Dräger
X-am 7000 comes as standard with a rubber
protective housing which protects it if
dropped up to 1.5 metres. Because the
sensors are not sensitive to shock, their
measurement function is not significantly
impaired by impact.
The Dräger X-am 7000 is also the only instrument
on the market which is fully immersion-
proof as per IP 67, meaning that
no repairs are necessary if an instrument
falls into water. In such cases, even the
sensors are protected by water-repellent
membranes. In addition, the optional sampling
pump is protected by Gore water-tight
membranes, preventing damage to the pump
due to pumped water.
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Pump operation starts automatically when
the pump adapter is connected. The pump
run-time is displayed by the instrument,
which is very useful for confined space
entry measurements, as dead-time in the
sampling path and sensor response times
have to be taken into account.
The pump is continuously monitored by a
flow sensor, which triggers an alarm in the
event of a malfunction.
Sampling can be conducted using a hose of
up to 45 metres in length. Depending on
the application in hand, a range of different
sampling probes are available to perform
confined space entry measurements: from a
straightforward hose or floating probe, to
rod probes, leak probes and various telescopic
probes. The optional pump can be easily replaced
or retrofitted simply by attaching it to the
Dräger X-am 7000.
Software
Operation
The intuitive three-key operation is easy to
learn. Incorrect operation by the user is unlikely,
as all messages appear in plain text.
The keys can even be operated easily by
users wearing thick protective gloves, and
the Auto Zoom function allows an enlarged
display of measured values if fewer than
five sensors are active.
Functionality
Users can configure a password-free quick
menu to suit their particular needs, giving
quick access to key functions (e.g. hygiene
functions like monitoring of TLV and STEL
values, info screens relating to the battery
etc.). The Info mode give access to information
on current warnings/errors, system
data (battery status, data log, clock), sensor
information such as measurement ranges,
and personal and session IDs. This information
can also be accessed when the instrument
is switched off, which makes it easier
for the service technician to prepare the instrument
for use.
The service technician can assign different
functions to the function key. This allows
the user to activate and deactivate additional
functions at the push of a button, e.g.
display maximum value, hold peak value, switch between Ex-sensor calibrations (e.g.
methane - nonane), leak detection mode.
Leak detection mode
The leak detection mode can be used in
conjunction with the catalytic EX sensor
calibrated to methane. The display then
shows a bar graph of the ppm range with
concentration changes in 50 ppm increments.
For added support, the instrument
emits a rising or falling tone, a bit like a
Geiger counter, to indicate the gas concentration
detected.
Data log
The instrument can be equipped with an
optional data log. At a sampling interval of
one minute, all gas concentrations and operating
conditions, together with their respective
dates and times, can be documented
for a period of around 50 hours.
Personal and session IDs can also be recorded.
With the aid of the GasVision
software package, the recorded data can
be analysed, visualized and edited. Data is
transmitted via an infrared interface.
Calibration possibilities
The instrument can be calibrated in various
different ways. Fresh air calibration and freely
configurable individual gas calibration or
mixed gas calibration are available. Once
calibration has been carried out successfully,
the quality of the calibrated sensor is displayed
in graphic form, allowing the service technician to predict whether a sensor will
need replacing during the next routine
service.
As with the instrument's predecessor, the
MultiWarn II, the EX sensor can also be
vapour-calibrated.
Accessories
A wide range of accessories is available for
the Dräger X-am 7000: for example, a
multiple charger station, the E-Cal module
for automatic adjustment, the GasVision PC
software for outputting and displaying the
recorded data, and the CC Vision PC software
as a tool to help service technicians
configure and calibrate the instrument,
providing optimum support for internal
company processes in the service technician’s
or safety engineer's workshop.
Ulf Ostermann
Dräger Safety AG & Co. KGaA |
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Dräger Safety AG & Co. KGaA |
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Revalstrasse 1 |
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23560 Luebeck, Germany |
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Tel +49 451 882 0
Fax +49 451 882 2080
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