Emerson MicroCEM - Manual (Page 50)

Instruction Manual
748467-A
January 2002
2-14 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
Model MicroCEM
2-5 ANALYTICAL LEAK CHECK
If explosive or hazardous gas samples are
being measured with the MicroCEM, it is rec-
ommended that gas line fittings and compo-
nents be thoroughly leak-checked prior to
initial application of electrical power, bimonthly
intervals thereafter, and after any mainte-
nance which involves breaking the integrity of
the sample containment system.
a. Flow Indicator Method
Supply air or inert gas such as nitrogen,
at 10 psig (689 hPa), to the analyzer
through a flow indicator with a range of 0
to 250 cc/min. Install a shut-off valve at
the sample gas outlet. Set the flow rate to
125 cc/min.
Close the outlet shut-off valve and notice
that the flow reading drops to zero. If the
flow reading does not drop to zero, the
system is leaking and must be corrected
before the introduction of any flammable
sample gas or application of power.
Figure 2-7. Leak Test Flow Method
Flow Meter N
2
10 psig
(69 kPa)
Gas Outlet
MicroCEM Analyzer
Inlet Outlet