Installing The Probe Directly Into The Process; Installing The Probe In A Sampling System - E+E Elektronik EE371 Manuel

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3.2

Installing the probe directly into the process

When installing a probe directly into the process, there should be a stop valve on both sides of the point of installation.
This makes it easy to remove the transmitter for maintenance and calibration.
3.3

Installing the probe in a sampling system

Sampling is necessary if direct installation of the probe in the process is not possible or not required. Reasons may include:
- an excessive process temperature
- protecting the sensor against soiling
- the need to remove the probe without interrupting the process.
To obtain a representative sample of the process gas and to avoid measuring errors, please note the following:
- Differences in pressure between the process and the sampling chamber will result in signifi cant measuring errors!
- Measurements at low dew point temperatures are sensitive to humidity penetrating from the environment due to leaks.
The sampling system must therefore be pressure-tight.
- No hygroscopic materials must be used!
- The sampling line should be as short as possible.
- The response time increases if the gas fl ow is < 1 l/min
- If the gas fl ow is too low, this can result in back-diffusion of humidity from the environment and distort the measurement.
Step 1:
Install the probe with the stop valves closed.
It is not permitted to use a sealing ring with a NPT 1/2" thread.
Appropriate PTFE sealing tape or sealant should be used instead.
Step 2:
Insert the probe into the process and screw it as tight as possible by hand.
Step 3:
If there is a sealing ring, check it for correct centring and tighten the
screw connection with a torque of 30 Nm.
.
(0.25 gpm)
page 22
EE371 / EE372