Appendix C – Functional Testing Using Gas
148
Senscient ELDS™
Rev 15
GB
CAUTION
The Gassing Cell supplied by Senscient has been very carefully designed and tested for use
with our laser-based ELDS OPGD products. ONLY use a Senscient supplied Gassing Cell in
conjunction with ELDS OPGDs.
CAUTION
The Gassing Cell utilises thin film windows which are relatively fragile. Do not attempt to clean
these windows using a brush or cloth. In order to remove any dust from the windows, careful use
of an air-duster is recommended.
12.2.1 Procedure for Filling Gassing Cell
CAUTION
The physical and chemical properties of some of the gases that can be detected by ELDS
OPGDs make it impossible to achieve a known, stable burden of such gases inside the Gassing
Cell. For this reason, Senscient advises against attempts to use ammonia, hydrogen chloride or
hydrogen fluoride gas inside the Gassing Cell.
In order to ensure the best possible results when using a Gassing Cell to check the response
(1)
of an ELDS unit, only use in-date cylinders of calibration-grade gas containing 20% or more
of their original fill pressure.
Do not use gas from cylinders that are nearly empty or that are very close to their expiry date;
(2)
since the gas in such cylinders will almost certainly produce low readings.
The Gassing Cell is designed to be filled and shut-off / sealed, so that it can subsequently be
(3)
used for testing over approximately an 8hour period.
Before connecting the gas cylinder to the Gassing Cell, open both of the Gassing Cell’s
(4)
valves.
Always use a flow regulator on the gas cylinder to protect the Gassing Cell from exposure to
(5)
excessive pressure and/or flow.
Attach the tubing running from the flow regulator to one of the Gassing Cell inlets / outlets.
(6)
Open the flow regulator and fill the Gassing Cell with gas. (NB: Maximum flow-rate of 1
(7)
litre/min.)
The volume of the Gassing Cell is approximately 1 litre. In order to ensure that the Gassing
(8)
Cell is completely and uniformly filled with gas at the same concentration as that in the
cylinder, it is essential that a quantity of gas corresponding to 5 times the Gassing Cell
volume is flown through the cell.
At a flow rate of 1 litre / min it will take at least 5 minutes to completely, uniformly fill the
Gassing Cell with gas at the same concentration as that in the gas cylinder. Do not attempt
to use the Gassing Cell until it has been properly filled as described.
Once the Gassing Cell has been filled with the test gas, it is necessary to stop the filling
(9)
process in a manner which does not pressurise the gas inside the Gassing Cell.
First, turn off the flow of gas into the Gassing Cell by turning off the flow regulator on the gas
(10)
cylinder.
Summary of Contents for Senscient ELDS 1000 series
Page 58: ...Installation Commissioning 58 Senscient ELDS Rev 15 GB 2 x Mounting Brackets ...
Page 140: ...Certification 140 Senscient ELDS Rev 15 GB 9 1 2 Control Drawing CENELEC ATEX ...
Page 142: ...Certification 142 Senscient ELDS Rev 15 GB 9 1 4 Control Drawing CSA US Canada ...
Page 159: ...Appendix D Manufacturer s EC Declarations Senscient ELDS Rev 15 159 GB ...
Page 160: ...Appendix D Manufacturer s EC Declarations 160 Senscient ELDS Rev 15 GB ...
Page 184: ...For local MSA contacts please visit us at MSAsafety com Because every life has a purpose ...
