WIKA TR25 Betriebsanleitung Seite 22

7. Information on mounting and operation in hazardous areas
7.4.2 Possible installation methods with the marking II 1/2 Ex ib IIC T6 Ga/Gb or
II 1/2 D Ex ib IIIC T65 °C Da/Db
Zones 0, 1, 2 or
EN
Zones 20, 21, 22
Thermowell
TWxx
Thermowell
TWxx
The sensor or thermowell tip protrudes into Zone 0. The housing or connection head is in
Zone 1 (Zone 21) or Zone 2 (Zone 22). It is sufficient to use an Ex ib type circuit.
Zone separation is guaranteed if sufficiently-tight (IP67) process connections are used.
Examples of suitable process connections include gas-tight standardised industrial flanges,
threaded connections or pipe connections.
The welded parts, process connections, compression fittings, thermowells or housings
used must be designed such that they withstand all influencing variables resulting from the
process, such as temperature, flow forces, pressure, corrosion, vibration and impacts.
22
Zones 1, 2 or
Zones 21, 22
Process
connection
Compression
fitting
welded
Process
connection
Connection head/
Field housing
Safe area
Hazardous area
Tx10-H
Tx10-A
Option:
with built-in
transmitter:
e.g. T32
Tx10-H
Tx10-A
Tx10-C
Tx10-D
Tx10-A
Tx10-B
Tx10-C
Tx10-A
WIKA operating instructions model TR25 (Ex i)
Associated
electrical equipment
Intrinsically
safe supply or
suitable barrier
Intrinsically
safe supply or
suitable barrier
Intrinsically
safe supply or
suitable barrier
Intrinsically
safe supply or
suitable barrier