WIKA TR21-A, Руководство по эксплуатации

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EN
14170746.05 03/2022 EN/DE/FR/ES
WIKA additional information model TR21 (Ex i) 15
5. Calculation examples for self-heating at the thermowell tip
5.1 Example calculation
Use at the partition to zone 0
The maximum possible temperature, T
max
, at the Ø 6 mm thermowell tip with transmitter is
being sought.
T
max
is obtained by adding the temperature of the medium and the self-heating. The
self-heating depends on the supplied power P
o
as well as the thermal resistance R
th
and is
15 K.
Example
Diameter: 6 mm
Medium temperature: T
M
= 150 °C
Temperature class T3 (200 °C) must not be exceeded
Self-heating: 15 K
T
max
= T
M
+ self-heating: 150 °C + 15 °C = 165 °C
As safety margin for type-examined instruments (for T6 to T3), an additional 5 °C must be
subtracted from the 200 °C; hence 195 °C would be permissible. This means that in this
case temperature class T3 is not exceeded.
Additional information:
Temperature class for T3 = 200 °C
Safety margin for type-tested instruments (T6 to T3) 1) = 5 K
Safety margin for type-tested instruments (T2 to T1) 1) = 10 K
1) EN/IEC 60079-0: 2012 section 26.5.1
6. Accessories
Accessories Order number
Connection cable with moulded connector M12 x 1
■
Cable box straight, 4-pin, ingress protection IP67
Temperature range -20 ... +80 °C
2 m 14086880
5 m 14086883
■
Angled socket, 4-pin, ingress protection IP67
Temperature range -20 ... +80 °C
2 m 14086889
5 m 14086891
5. Calculation examples for self-heating ... / 6. Accessories