Super Systems DP2000 - Manual (Page 4)

SSi Super Systems Inc.
Product Manual - Model DP2000 Portable Dew Point Analyzer
SSi Manual 4545 – DP2000 Super Systems, Inc. Page # 4 of 17
Revision Level “F” (800 ) 666-4330
Heat Treat Furnace Sampling: A gas sample may be extracted from a process using the
built-in pump. The sample tube from which the sample is taken out of the furnace should
extend into the furnace past the HOT face of the refractory. For accurate results, a
designated sample port should be used to extract the sample. SSi offers a sample port
assembly (part number 20263) which is ideal for this purpose. If a designated sample
port is not available, then a clean “burn-off” port on a Gold Probe
™, an industry leading
oxygen sensor for atmosphere control, can be used. Readings taken from the burnoff port
on a probe may be artificially high due to the presence of soot in the probe sheath.
Endothermic Generator Sampling: For applications under pressure, the pump should be
switched off and the flow controlled by the small restriction valve on the flow meter. A
flow rate between 1.5 and 2.0 SCFH is ideal. The sample should be taken from the
endothermic gas manifold after the gas has been cooled. NOTE: Allow the sample port
to blow out any soot and / or water before connecting the sample tube. Failure to do
so will result in inaccurate readings and expose the sensor to potential damage.
Instrument Damage –
The two main causes of damage to the DP2000 are the ingestion of soot and water. Both
of these contaminants will cause erroneous readings in the short term, and cause long-
term damage to the sensor and internal components.
Soot / Particulate Contaminants
When taking a sample from a furnace or a generator, care should be taken to reduce the
amount of soot that enters the instrument. The in-line filter will trap these particles, but
cleaning the sample line before attaching the DP2000 will increase the life of the filter.
Furnace ports can be burned off by pumping air through them while hot, or by removing
them from the heat and mechanically cleaning them. Generator ports should be opened
before the instrument is attached to allow any particulate buildup to be blown out. It is
also helpful to tap on the port while it is being blown out to eject any loose particles
before the instrument is attached.
If soot is allowed to collect on the dew point sensor in the instrument, it could result in
higher readings. This soot will also retain moisture than can corrode the sensor over
time. The sensor tip can be cleaned by carefully removing it from the sample block (see
Section 2.3 of the Field Calibration instructions) and rinsing it in isopropyl alcohol. The
power should be off while this is done, and the power should remain off for at least 30
minutes after this procedure to allow all of the alcohol to completely evaporate.
Water / Moisture Contamination
When a furnace or generator is being started up or cooled down, the resulting gases will
contain unusually high amounts of CO2. When these gases cool, moisture will
precipitate out and become condensation inside the sample tubing assembly. Even if the