Super Systems DPC3500 - Manual (Page 3)

Model DPC3500
Continuous Low-Range Dew Point Analyzer
PRODUCT MANUAL
Super Systems, Inc. DPC 3500
Manual # 4551B Page 3 of 5
P/N 13123
Remote Mounting Assembly
Sample Cell Installation:
The cell must be installed in the Remote Mounting Assembly (SSi Part Number
13123), which is provided with the unit. All of the necessary components for
installing the sensor are included in this kit. Although this installation does allow
for some design flexibility, it is important that only stainless steel tubing and
fittings are used to carry the sample gas to the sensor.
When installing the unit, verify that all fittings are tight,
since any leaks will cause inaccurate readings.
During the operation of this unit, sample gas will constantly
be flowing through the sensor and out of the vent.
Depending upon the type of gas being sampled,
appropriate safety precautions should be taken for proper
venting of the sample gases after they exit the sampling
assembly.
Sample Tubing Materials:
When determining the moisture content of gas samples,
the materials used to transport the gas samples are
extremely important. As the gas passes through tubing,
the polarity of the moisture molecules will cause them to be
attracted to the tubing. Any moisture that remains on the
wall of the vessel does not have the opportunity to travel to
the sensor, so it will reduce the sensor’s response time.
Also, some tubing materials (rubber, copper, PVC, etc.) are
porous enough to allow for moisture penetration directly
through the walls of the tubing, even in cases where there is considerable
positive pressure.
Super Systems, Inc. recommends that only stainless steel is used as the tubing
material for measuring low dew points (below -50
°F). It is also important to note
that to maintain the integrity of the entire sampling system, all of the necessary
valves and fittings should also be constructed of stainless steel. These material
precautions do not need to be followed “downstream” (after the sensor), since
the moisture content of the gas at this point is unimportant.
Calibration:
The calibration of the DPC3500 is traceable to National Institute of Standards
and Technology (NIST) standards. Each sensor has a unique serial number, and
the calibration data can be found on the Certification Sheet located at the back of
this manual. Due to the sensitivity and complexity of the metalized ceramic
moisture sensor, this unit cannot be user calibrated and must be returned to SSi
for recalibration and recertification. It is recommended that the sensor be
recalibrated every twelve months. Each sensor is interchangeable without the
need for display recalibration, so only the sensor needs to be returned for
recalibration, not the entire panel.