Specifications

Use of Analytical Module Hardware Test Box, continued
The following procedure should be used to test for internal leaks within
an analytical module. Refer back to figure 4-12 during this procedure.
Leak Test
Checking for leaks using the Module Tester is accomplished by
pressurizing different parts of the module to a specific pressure (typically
100 psig) using input gas. Then, the pressurized volume is sealed off
and the gas pressure gauge is monitored to determine if there is a
pressure loss over time.
The amount of pressure loss over time depends on the size of the leak
or leaks that exist as well as the size of the analytical module. Very small
leaks may take several minutes to leak enough gas to be detectable on
the gauge.
All pneumatic fittings are likely to leak a very small amount. The amount
of acceptable leakage depends on where on the module a leak is and
also on specific customer requirements. For example, a leak on a valve
actuation tube is not likely to affect analytical results, but could increase
utility costs.
The steps in the procedure below are designed to allow the user to
quickly detect cumulative leaks of 0.5 ml per minute within the largest
possible analytical module. This is considered the minimum requirement
and is usually sufficient to prevent significantly affecting chromatographic
results. If a customer requires a lower level of leakage, then the test
times can be extended. The customer may also choose to leak test each
fitting directly with a leak detector instead of waiting to detect a pressure
loss.
Step Procedure
Note: Leak checking is accomplished using the VALVE switches
on the Module Tester. During leak checking only one of
these switches is used at a time. Turning on more than one
switch may prevent the test from functioning correctly.
1. Verify that the test box is set up as described previously in
this section. Ensure that the switches labeled VALVE 1,
VALVE 2, and VALVE 3 are all set to OFF.
2. Turn MAIN VALVE to INLET. This supplies gas pressure to
the valve switches on the test box.
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