Sample System Guidelines - GE PM880 Operations & Installation Manual

August 2003

Sample System Guidelines

A sample system is highly recommended for moisture
measurement. The purpose of a sample system is to condition or
control a sample stream to within the specifications of a probe.
The application requirements determine the design of the sample
system. GE Panametrics applications engineers will make
recommendations based on the following general guidelines.
Typically, sample systems should be kept very simple. They
should contain as few components as possible and all or most of
those components should be located downstream of the
measurement probe. Figure 2-1 on page 2-7 shows an example of
a simple sample system consisting of an explosion-proof housing
with a sample cell, a filter, a flow meter, a vent valve and two-
shut off valves, one at the inlet and one at the outlet.
The sample system components should not be made of any
material that will affect measurements. A sample system may
include a filter to remove particulates from the sample stream or a
pressure regulator to reduce or control the pressure of the stream.
However, most common filters and pressure regulators are not
suitable for sample systems because they have wetted parts that
may absorb or release components (such as moisture) into the
sample stream. They may also allow ambient contamination to
enter the sample stream. In general, you should use stainless steel
material for all wetted parts.
Contact the GE Panametrics PCI Division at 1-800-833-9438
(within the USA) or 781-899-2719 (outside the USA) for further
instructions.
2-6 Initial Setup