No restrictions. However, self-draining in the process must be guaranteed. If there is an opening to
detect leaks at the process connection, this opening must be at the lowest possible point.
The immersion length of the thermometer can influence the accuracy. If the immersion length is too
small then errors in the measurement are caused by heat conduction via the process connection. If
installing into a pipe then the immersion length should ideally be half of the pipe diameter.
Installation possibilities: Pipes, tanks or other plant components
A0008946
1Installation examples
1, 2 Perpendicular to flow direction, installed at a minimum angle of 3° to ensure self-draining
3On elbows
4Inclined installation in pipes with a small nominal diameter
UImmersion length
Endress+Hauser3
In the case of pipes with a small nominal diameter, it is advisable for the tip of the thermometer
to project well into the process so that it extends past the pipe axis. Installation at an angle (4)
could be another solution. When determining the immersion length or installation depth all the
parameters of the thermometer and of the medium to be measured must be taken into account
(e.g. flow velocity, process pressure).
The use of iTHERM QuickSens inserts is recommended for immersion lengths U <
70 mm (2.75 in).
2Detailed installation instructions for hygiene-compliant installation
1Sanitary connection according to DIN 11851, only in connection with EHEDG-certified and self-centering
sealing ring
2
Varivent® process connection for VARINLINE® housing
3Clamp according to ISO 2852, only in connection with seal according to EHEDG position paper
4Liquiphant-M G1" process connection
A0011758-EN
iTHERM TT412
The counterpieces for the process connections and the seals or sealing rings are not included in
the scope of supply for the thermometer. Liquiphant M weld-in adapters with associated seal
kits are available as accessories.
Procedure in case of seal failure:
• Disassembling of the thermometer, validated cleaning procedure of thread and sealing ring
groove
• Replacement of the seal or sealing ring
• CIP after re-assembly
In the case of weld-in connections, exercise the necessary degree of care when performing the
welding work on the process side:
• Suitable welding material
• Flush-welded or with welding radius > 3.2 mm (0.13 in)
• No recesses, folds or gaps
• Honed and polished surface, Ra ≤ 0.76 µm (30 µin)
4Endress+Hauser
iTHERM TT412
L (mm)
A
0
10
20
30
40
50
60
70
80
90
100200300400500
v (m/s)
B
0
48121620
L (in)
0
30
65
100
130
160
200
230
260
290
v (ft/s)
Process
Process temperature range
Thermal shock
Process pressure range
Maximum –200 to +650 °C (–328 to +1202 °F)→ 7
Thermal shock resistance in CIP/SIP process with a temperature increase from
+5 to +130 °C (+41 to +266 °F) within 2 seconds.
The maximum possible process pressure depends on various influencing factors, such as the design,
process connection and process temperature. For information on the maximum possible process
pressures for the individual process connections, see the 'Process connection' section. → 8
It is possible to check the mechanical loading capacity as a function of the installation and
process conditions online in the Thermowell (TW) Sizing Module for protection tubes in the
Endress+Hauser Applicator software. See 'Accessories' section.
Example of the permitted flow velocity depending on the immersion length and process
medium
The highest flow velocity tolerated by the protection tube diminishes with increasing insert
immersion length exposed to the stream of the fluid. In addition, it is dependent on the diameter of
the tip of the protection tube, the medium type, process temperature and process pressure. The
following figures exemplify the maximum permitted flow velocities in water and superheated steam
at a process pressure of 40 bar (580 PSI).