Galvanic Applied Sciences 943-TGX, Руководство по эксплуатации

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Revision 4 26 August 02, 2019
sample system clogging (liquid accumulation), the
Zero Air Flow Adjust Valve
may be opened
wide to provide a solid back purge pressure. Alternately, the
Zero Air Flow Adjust Valve
may
be turned down to a trickle for an extended period (20-30 minutes) allowing the heat of the
oven to re-liquefy any solid accumulation (plugging) before increasing the back purging
pressure to clean out the plumbing.
3.2.5 Aspirator Drive Air Flow Adjust Valve
The Aspirator Drive Air Flow Adjust Valve controls (indirectly) the rate of process sample gas
extraction from the tail gas duct. The aspirator drive air is plumbed to a venturi type eductor
integral to the measurement cell block. The design of the analyzer sample system is such
that process sample gas is extracted from near the centre of the process duct, and vented at
the wall of the process duct through the same access port. Ideally, enough aspirator drive air
is provided to present a measurement cell pressure of 2-3" H2O below the process duct
pressure.
In practice, the aspirator drive air flow adjustment is made to obtain a nominal 5-10 second
stabilized sample response time from a ‘zeroing’ state. (The length of time is impacted by the
actual probe length.) This adjustment is made by monitoring the time required for the
analyzer display outputs of gas concentration to return to a stable process level, after the
‘zero’ state has been released.
3.2.6 System Regulator
The system regulator is normally set to 30 psig. The absolute value of this setting is not
critical for system operation however, sufficient pressure to provide adequate sample
aspiration and system zeroing is necessary. In situations where additional supply pressure is
required, the system regulator may be adjusted to its maximum output of 50 psig without
harming the analyzer.