Vaisala HMT330 Guía De Referencia Rápida página 3

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About This Quick
Guide
This Quick Guide provides an overview on
how to install Vaisala HUMICAP
Humidity and Temperature Transmitter
Series HMT330, Vaisala DRYCAP
Dewpoint and Temperature Transmitter
Series DMT340 and Vaisala HUMICAP
Moisture and Temperature Transmitter
Series for Oil MMT330. Please refer to the
relevant User's Guides for detailed
information on the use of the products.
Things to Consider
When Measuring Dewpoint
- If a sampling system is built instead of
direct probe installation, it is important that
the system is leak-proof. Recommended
material for sampling system construction
is stainless steel. Also PTFE may be used
down to dewpoints of -40°C / -40 °F.
- Dewpoint is a pressure dependent
parameter. It is important that the pressure
at the sensor is the true process pressure.
The temperature is not of major
importance, as long as it is above the
process dewpoint in order to avoid
condensation.
When Measuring Relative
Humidity
In humidity measurement it is essential
that the temperature of the probe and the
measured gas is the same. Even a small
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difference in temperature between the
environment and the probe can cause an
error of several percentages in RH.
Mounting the Probes with Cable
Mount the probes with a cable with the
®
sensor head horizontally or vertically. This
way, any water condensing on the tube
®
cannot flow onto the sensor.
When installing probe into a chamber with
®
a higher T than the surrounding the point
of entry must always be carefully
insulated. The cable must also be allowed
to hang loosely as this prevents any
condensed water from running onto the
sensor head along the cable.
Figure 1
Numbers refer to Figure 1 above.
1
2
3
4
- Refer to the appropriate User's Guides for
further installation instructions for probes
with a cable as well as other installation
possibilities.
Horizontal Mounting of
Sensor Head
= To be sealed.
= To be insulated.
= Insulate the cable.
= Let the cable hang loosely. This
prevents condensed water running to
the sensor along the cable.
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