KROHNE OPTITEMP TRA-TCA EN - Manual (Page 16)

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DEVICE DESCRIPTION
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OPTITEMP TRA/TCA
www.krohne.com 08/2010 - 4000630501 - MA OPTITEMP TRA/TCA R01 en
2.2.5 Neck tubes
The neck tube connects the process connection (i.e. screw socket or flange) to the connection
head. Its function is to thermally decouple the connection head so that it and any existing
temperature transmitter do not heat up too much. See below for an example of a neck tube:
The materials, diameter and wall thickness of the neck tube and the thermowell are identical.
The standard length of a neck tube is 145 mm / 5.7" (with screw-in thread as process
connection) or 80 mm / 3.1" (with flange as process connection). The manufacturer can provide
other neck tube lengths on request.
2.2.6 Thermowells and thermowell tips
The thermowell is designed to prevent external loads (e. g. static pressure, flowing and
aggressive media) from damaging the measuring insert. As a rule, thermowells are made of the
same material as the system in which the measuring is done. In terms of the material and
design, we can distinguish between two types of thermowells:
• Multipart, welded thermowells
• One-piece bar stock thermowells
This handbook deals with thermometers with multipart, welded thermowells. The "Industrial
thermometers for increased requirements" handbook contains information about industrial
thermometers with bar stock thermowells.
Figure 2-2: Neck tube
1 Neck tube
2 Thermowell
3 Process connection (here with G½" thread)
4 Connection head thread M24 x 1.5
.book Page 16 Tuesday, August 17, 2010 12:18 PM