GB
MSA ACCESSORIES
Series 47K Gas Detector [SIL 2] 27
Note: Operating the remote calibration adaptor CalGard together with the gas
detector model S 47K-PRP is included in the EC-Type Examination Certificates
DMT 01 ATEX G 001 X, BVS 03 ATEX G 010 X and DMT 03 ATEX G 003 X.
The CalGard stainless steel remote calibration adaptor provides reliable operation
of remotely installed gas detectors working under harsh environmental conditions.
Additionally, the CalGard allows remote verification ("bump test") or instrument
calibration of gases listed in Section 6.6.2 via a hose connection in the presence
of wind speeds up to 6 m/s. In normal measurement operation, the ambient air
passes through the air vents into the remote calibrator directly to the sensor
(diffusion operation). During a bump test or instrument calibration, the test gas is
supplied to the sensor via the hose connection at the bottom of the CalGard. An
integrated mechanism prevents the dilution and dispersion of test gas otherwise
caused by external influences, such as wind. This allows a fast response from the
sensor to the applied test gas. To compensate for possible deviations during
measurement of flammable gases a calibration factor of 1.05 shall be applied
when using the CalGard for remote calibration.
Once calibration is complete, the air inlet reopens to allow the monitoring of
ambient air for gas without the need for further user intervention.
6.6.1 Installation
For correct operation, Sensor S47K and CalGard must be used in a vertical
position (hose connection pointing downwards). The CalGard remote calibrator
can be attached to the sensor by screwing on the thread of the detector.
Note: The tube connector is adapted for tubes with an inner diameter of 5 mm.
In general the hose should be as short as possible in order to:
Minimise the gas volume needed to flush the tube
Reduce external influences (e.g. temperature shift, pressure, etc.)
Minimize the lead time
Hose material should be adapted to the applied test gas, have no absorptive or
adsorptive properties and should be made from inert material such as teflon or
polyethylene. When using the CalGard in the hazardous area, a conductive hose
must be used.
Note: The free end of the test gas tube must be closed if no test gas is applied.
This is to prevent gas or air passing through the tube to the sensor, distorting the
measurement or in the reverse pressure conditions, the ambient atmosphere
escapes from the sensor at the free end of the tube.
Note: To ensure proper function the CalGard must be kept dry and free of any
contaminants, e.g. dust particles. Regular visual checks are recommended. Any
contaminants must be removed by blowing them off with clean, oil-free
compressed air or with a dry brush. Ensure that the air entrances are kept free
from any coating, e.g. paint, grease or similar.
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