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Portable gas detectors can be used in
many very different ways. Checking safety
before starting work in confined spaces, for
example, can be done using various measurement
concepts. The Dräger Pac (single-gas
detectors) and X-am (multi-gas detectors) families are built to meet the requirements
of such applications and to maximize workplace
safety. The "family design" and wide
range of accessories on offer optimize work
processes and therefore ensure economical
use of the detectors. |
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Confined space entry measurements
Before personnel can enter a confined
space in which gas hazards might be present,
an all-clear measurement must be
performed by those responsible for safety.
Multi-gas detectors with an inbuilt internal
pump – e.g. the X-am 3000 and X-am
7000 – are ideally suited to this purpose. |
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Gas detector carried as personnel air
monitor
Once an all-clear measurement has been
performed, each member of staff is given
their own "personal gas detector". The small,
lightweight Dräger X-am 2000 multi-gas
detectors and the single-gas detectors of the
Pac series are perfect for this application. |
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Gas detector for area monitoring
In a confined space, a gas detector can
be set up and surrounded by a group of
people. Confined spaces with a floor area
of 50 to 75 square metres or a radius of
five to seven metres around detectors like
the Dräger X-am 3000 or 7000 can be
classified as safe.. |
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Leak detection
Portable gas detectors are also used to
actively search for gas hazards. For instance,
they can be used during the course of
maintenance work to check that industrial
valves are leak tight. Gas detectors with an
internal pump, like the Multi PID II, X-am
3000 or X-am 7000, are well-suited to this
purpose. |
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Monitoring carried out by safety
attendants
Safety attendants can use pump-based gas
detectors like the Dräger X-am 3000 or
7000 to detect gas hazards in confined
spaces. Floor areas of 50 to 75 square
metres, or a radius of five to seven metres
around the sampling point, can be classified
as safe. In many cases, this application is
combined with personal gas detectors or
area monitoring devices in a confined space. |
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Solutions to optimize work processes
In the morning: function tests and
calibrations
It is possible to distinguish between the use
of a gas detector as a test station for function
tests in the field, and a workshop solution
used by service personnel. By law, gas
detection instruments have to be subjected
to a function test using test gas before
being used in safety-related applications.
These function tests, known as bump tests,
are performed in some companies by personnel
on site. In such cases, a straightforward
and fast solution with a low gas
consumption is needed – like the Dräger
Bump Test Station. Workshop solutions like
the Dräger E-Cal Station are professional
full service stations. At the push of a button,
processes such as function tests, calibration,
adjustment, readout of stored data and
checks of battery status can be carried out
automatically. Instrument configurations can
be performed easily, and in addition the
PC-based station is ideal for use in data
and instrument management. |
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During the day: the detector in use
The optimum design of a gas detector
varies in accordance with which of the
aforementioned applications is required.
- Personal gas detectors tend to be
selected mainly on the basis of wearing
comfort. They need to be small and light
enough not to disturb the user during
their work. What is more, such detectors have to be extremely easy to operate
since they are used by all employees.
- Area monitoring instruments are stable
and sturdy, and feature a loud alarm
which is visible from all angles.
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The trustworthy core at the heart of the
gas detector – the sensor technology
Because the life of each worker depends
on the proper functioning of the gas detector
when the instrument is being used
in gas-hazard areas, sensor technology
which will provide a dependable warning
is essential. DrägerSensors are famous for
their reliability. For example: catalytic Ex
sensors should be sensitive not only to
explosive gases like methane, as organic
vapours (e.g. petrol fumes) can in many
cases pose an explosion hazard.
Dräger's catalytic Ex sensor is highly sensitive
to organic vapours such as nonane,
and therefore offers a particularly high level of reliability in every application.
To prevent electrolyte leaks in electrochemical
sensors, the electrochemical
DrägerSensors of the XS and XXS series
feature a patented system of pressure compensation
in the 700 to 1300 mbar range.
Dräger's patented electrochemical oxygen
sensor is designed on the basis of threeelectrode
technology, with no consumable
parts. This gives the sensor a life span of
more than five years, which considerably
reduces the costs of ownership. |
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Withstanding the tough demands of
routine industrial use
Portable gas detection instruments must be
tough enough to withstand the demands of
everyday industrial use. Fully dust- and
water-proof instruments with IP 67 approval
are best suited to meeting this requirement.
What is more, gas detectors are often used
in the vicinity of electromagnetic fields (e.g.
radio devices). An instrument is considered
to be highly resistant to electromagnetic influence
if it remains unaffected by antennae
situated at a distance of 10 centimetres
from the instrument. Shock-absorbing
protective rubber sleeves or rubber-coated
housings are the industrial standard, and
protect the detectors in the event of a fall
or impact. Catalytic sensors are, generally
speaking, shock-resistant, though the sensors
will only withstand being dropped,
kicked or hit if the instrument or sensor
is intelligently designed. |
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Distribution and return of detectors:
registration and data management
When the serviceman has to distribute a
huge pile of detectors first thing in the morning,
speed is of the essence to avoid long
queues of people waiting. To accelerate
this process and to simplify the return of
the equipment at the end of the day,
Dräger provides a registration tool in the
form of its CC Vision workshop software.
One modern way of transmitting the detector's
data or event logger to a PC is via an infrared interface. Software solutions
like GasVision offer professional help with
data visualization and analysis. |
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After work: cleaning of equipment
At the end of a hard and dirty day's work,
the detectors are handed back in, often in
desperate need of a shower. Water-proof
detectors featuring protection class IP 67
can in fact be cleaned using a wet sponge.
(Figure 13). |
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During the night: recharging
Because different companies have different
strategies when it comes to recharging of
equipment, different solutions are needed.
For individual instruments, individual charging
is possible, with cascadable multiple
charging stations for larger numbers of instruments.
Of course, charging can also
take place in a vehicle. Vehicle installation
kits have to be tough enough to pass the
so-called 10 G test which simulates vehicle
acceleration (Figure 14). |
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Conclusion
A number of different aspects have to be taken into account in order to ensure economic
and cost effective operation of portable gas detection equipment. Selecting the detector
best suited to the task in hand is a key factor, while on the other hand intelligent workshop
solutions can help optimize work processes and, therefore, reduce the costs of ownership.
Dräger developed the X-am family of multi-gas detectors and the Pac family of single-gas
detectors with the needs of users in mind. In combination with the accessory solutions
available for these product series, operating costs and work processes are optimized. |
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Ulf Ostermann
Dräger Safety AG & Co. KGaA
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