Internal Sample Bypass; Hardware Installation - Honeywell ENCAL 3000 Hardware Manual

Gas will enter at the first (lower) valve which will guide the flow to the second (upper)
valve in actuated situation.
The second valve guides the flow into a common channel. In deactivated situation, the
input from the first valve is blocked and the output is linked to the relieve port of this
valve, which vents to the SBV vent. The input of the second valve is also blocked so it is
not possible to build up pressure between both valves. In case one or both valves would
leak, the pressure between the valves won't rise above the pressure that is present in the
common channel because of the vent to the SBV vent, so mixing up the streams is not
possible.
5.4.2

Internal Sample Bypass

The output from all second valves is combined on the common channel. Depending on
which channel is activated, a section of this channel and the deactivated valves, form a
dead volume. The outputs from deactivated valves are therefore relieved to a second
common vent channel, which is blocked by the sample bypass valve. Activating this valve
will result in a flow from the activated valves, through the deactivated valves, to the
bypass valve. This refreshes all second valves and the common channels with the new
gas, so all dead volumes are refreshed. Actuating the bypass valve results in a flow that
is approximately 15 times higher than the normal flow. The purge valve should be
activated for a short period (±30 seconds default) when a new stream is selected.
If there is a long sample line between the sample point and the Encal, or there is a
relatively high pressure in this line the bypass time can be increased up to 150 seconds.
The new stream is selected one analysis prior to the injection, so during the analysis the
new sample is already flushed through the manifold. The best moment to activate the
sample purge is ending 10 seconds before the injection and then extended to the front
depending on the purge duration.
Keep in mind the purge time also applies to the calibration gas which must be purged,
but larger purge times and frequent purging will deplete the bottle faster. Further
information for the needed setting in the software can be found in the software manual.
The flow through the analytical modules will be reduced during the activation of the
bypass, but will continue. Closing the bypass valve will restore the normal flow to the
analytical modules. After the sample gas has passed the manifold it becomes split for
the transport to the two analytical channels. The vent outputs from both modules return
to the manifold and are combined to two venting outputs.

6 Hardware Installation

EnCal 3000 Hardware Manual
All safety and warning notes in this document must be observed before
further workis done
CAUTION
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HARDWARE INSTALLATION
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