WIKA TR25 - Handbuch (Seite 20)

14073045.01 10/2013 GB/D
20 WIKA operating instructions model TR25 (Ex i)
GB
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
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 (IP 67) 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.
Zones 1, 2 or
Zones 21, 22
Hazardous area Safe area
Thermowell
Thermowell
welded
TWxx
TWxx
Process
connection
Connection head/
Field housing
Tx10-B
Tx10-C
Tx10-C
Tx10-D
Tx10-H
Tx10-H
Option:
with built-in
transmitter:
e.g. T32
Tx10-A
Process
connection
Compression
fitting
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
Tx10-A
Tx10-A
Tx10-A
Zones 0, 1, 2 or
Zones 20, 21, 22
7. Information on mounting and operation in hazardous areas