Servomex DF-310E, Руководство оператора

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38 DF-310E Sample Gas Preparation and Delivery
specifications. However, in most cases the error introduced is relatively
small, and may not affect the process application.
NOTE
It is not recommended that gauges be installed upstream of the
analyzer. The presence of a gauge increases response times and
introduces potential leaks to ambient.
Sample gas line lengths, fittings and bends should be kept to a minimum to
maintain low pressure drops. Larger diameter tubing and fittings reduce
pressure drop and also lengthen response time. In general, 1/8-inch tubing
should be limited to 15-foot runs; longer runs should be made with 1/4-inch
tubing.
6.3.7 Sample Outlet Backpressure Effects
It is always recommended to vent the analyzer to atmospheric pressure.
However, if a sample vent or return line is used, attention must be given to
maintain a low and consistent backpressure so as not to affect the flow rate.
The allowable backpressure on the sensor is ±1 psig. If variations in the vent
line pressure are expected, a sub-atmospheric backpressure regulator should
be installed on the vent line to maintain an even backpressure on the analyzer.
Consider the regulator’s pressure drop (typically 1 psi) when designing the
sample vent system in order to stay within the ±1 psig pressure limits at the
sensor.
When not venting the analyzer to atmosphere, it is also suggested to install a
fairly high resolution pressure gauge immediately at the analyzer outlet.
NOTE
If a regulator or gauge is installed on the analyzer outlet, the
Stainless Steel Downstream Plumbing option should be installed.
6.4 Sample Gas Compatibility
There are a wide range of considerations in determining the gas sample
compatibility of the Process Oxygen Analyzer. Servomex attempts to identify
all pertinent application details prior to quoting and order processing. All
non-typical applications concerning gas sample compatibility must be
reviewed by our in-house Application Engineers. It is impossible to
accurately predict all of the chemical tolerances under the variety of process
gases and process conditions that exist.
6.4.1 Condensation
The analyzer should be installed and operated with a sample gas that is
preconditioned (if necessary) to avoid condensation in the gas lines. Several
methods are available to minimize the possibility of condensation. If the