|
|
Why install analyzers in an analyzer shelter? |
|
Answer
|
Although most analyzers are designed and built to install in the field without
further protection, grouping of analyzers together in one shelter had become
more popular. Installing equipment in an analyzer shelter protects the
analyzers against adverse ambient condition that may cause errors in the
analyzer readout. Grouping of analyzers in this manner also results in ease
of maintenance than analyzers that were installed separately.
back to top |
|
|
What are the advantages of installing analyzer system in a pre-fabricated
analyzer shelter? |
|
Answer
|
The great advantages of choosing a pre-fabricated analyzer shelter is that the
complete assembled analyzer systems are pre-piped and pre-wired to all
the analyzers and sample conditioning systems. All necessary utilities and
power distributions are also pre-installed at the factory. The complete assembled
system are then fully tested with test gases and shipped to site as a single
package. In this way, minimum site installation work is required.
back to top
|
|
|
Why do we need a Sample Conditioning System for a process analyzer? |
|
Answer
|
Sample Conditioning System that are designed and built to provide the correct
process parameters to the analyzer, which can control the process at optimum
efficiency to produce on specs end products. The primary objective of a Sample
Conditioning System is to extract sample from the process stream and deliver
it to the process analyzer to ensure that:
(i) sample composition/component measured by the analyzer is representative of the
process stream
(ii) sample to be measured is in the correct condition samples with the analyzer
measurement technique
(iii) the required response time for the analyzer to detect the process condition
changes in order for the analyzer to give a continous representative sample
reading.
back to top
|
|
|
Why do some Analyzer Systems need Atmospheric balancing control
and some don't? |
|
Answer
|
Atmospheric balancing is a technique applied for adjusting the sample pressure
to atmospheric pressure where the sample pressure is expected to fluctuate
and is commonly used for process gas chromatograph analyzer applications.
This can be done by installing a solenoid valve to block the sample to the
analyzer and another 3-way solenoid value to vent the sample to atmosphere
before sample injection.
back to top |
|
|
Why do we need the Double Block and Bleed Systems in the Multi-Stream
Switching Systems? |
|
Answer
|
As analyzers are relatively expensive such as process gas chromatograph
and in order to save some cost, such analyzer systems are design using
multi-stream switching system. However, possibility of cross contamination
between different streams is highly possible. One way to eliminate is to
incorporate "Double Block and Bleed Systems" into the Sample Conditioning
Systems. This type of systems uses two air-operated valves (AOVs) for each
stream. When the valves are de-energized, the tubing between them is
vented to the atmosphere, thus preventing contamination. A secondary bypass
is used to scavenge all sample lines, keeping all samples current. The double
block valves is to prevent sample contamination to the other streams in case
the first valves leaked. A good way to check whether the valves are leakage is
to install a leak bubbler at the atmosphere vent tubes. Symptom of bubbling
indicates a leak in one of the valves.
back to top
|
|
|
Why do some samples need heating or tracing? |
|
Answer
|
For gas samples, Electrical or Stream Heating/tracing is applied to the sample
lines or Sample Conditioning System components to maintain the sample above
its dew point to keep the sample fluid in vapor state, otherwise condensation
may occur. To vaporize a liquid sample can be done by reducing the pressure
or increase the temperature to a condition, which sample will change into
vapor.
back to top
|