MSA Senscient ELDS 1000 series, Руководство по эксплуатации

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Appendix C – Functional Testing Using Gas
154
Senscient ELDS™
Rev 15
GB
The Cross Duct Refillable Gas Test Cell can be filled by following the procedure below:
Open the cell filling valve by carefully rotating the brown valve seal control anti-clockwise until (1)
there is a gap of approximately 1mm between the brown valve seal control and the white
valve body. (This fully opens the filling valve.)
Carefully press the Gas Test Cell bag walls together such that any gas inside the bag is (2)
pushed out through the opened filling valve. (This step should ensure that there is no gas
inside the Gas Test Cell bag before filling.)
Connect up a flow regulated supply of 100%v/v methane to the filling valve inlet. (3)
Turn on the supply of 100%v/v methane and watch the Gas Test Cell bag inflate. When the (4)
Gas Test Cell bag is full, the walls at the centre of the bag will be approximately 8-12mm
apart. Once full inflation has been reached, switch off the supply of test gas.*
Disconnect the test gas. Allow any pressure that might have built inside the Gas Test Cell to (5)
be relieved through the open filling valve.
Close the cell filling valve by carefully rotating the brown valve seal control clockwise until (6)
valve is finger tight. ( NB: The cell filling valve is shut when the valve seal control is finger tight
and should not be further tightened using hand tools.)
CAUTION
In order to achieve best results and avoid the risk of bursting the Gas Test Cell bag, take care
not to pressurise or overfill the Gas Test Cell when filling.
If during use for testing, the reading produced by a Gas Challenge Cell is significantly lower
than expected it is possible that some of the methane may have escaped from the cell. In
such circumstances refill the cell with methane and re-test.
Cross Duct ELDS systems are configured to signal readings on their 4-20mA outputs that
are scaled in proportion to %LFL. Cross Duct ELDS units calculate the %LFL based upon
the assumption that there is a uniform concentration of gas across the whole width of the
duct.
%LFL =
(ppm.m Gas Measured) x 100
(100%LFL in ppm) x Duct Width (m)
Where:
ppm.m Gas Measured = Number of ppm.m methane measured
100% LFL in ppm = 100% LFL of methane expressed in ppm
Duct Width = Width of duct in metres (m)