Heinrichs Messtechnik GmbH
Page 8 of 20
TM/TMU/TM-SH Supplement Manual
For Explosion Flow-meters
3.3
Mounting
The mounting instructions for the standard sensor also apply to the explosion-proof sensor.
3.3.1
Thermally insulated sensor
The sensor may be outfitted with thermal insulation, also in explosive atmospheres. However, so not to impair
the junction box or connectors thermal ratings, the insulation shall only cover maximum the half of the sensors
neck onto which the junction box or connector is mounted.
3.3.2
Heated sensor
The sensor can be externally heated to avoid crystallization in the flow tube. Any heating technique or device
can be used. When using electrical heating devices, these must be suitable for use in the potentially explosive
environment present.
It is the operator’s responsibility to ensure that the heating temperature does not exceed the maximum
allowable temperature for the fluid and/or the maximum allowable temperature range for the potentially
explosive atmosphere in which the device is being operated.
The maximum allowable temperature range for the fluid is indicated on the sensors rating plate.
It is also the operator’s responsibility to ensure that no hazards are created by hot surfaces pursuant to
EN 1127-1 (Explosive atmospheres – Explosion prevention and protection) paragraphs 5.2 and 6.4.2.
3.3.3
Connection remote sensor – transmitter
A dedicated cable SLI2Y (SP) CY 5 x 2 x 0.5 mm² [blue] or similar is to be used for the electrical connection
between sensor and the remote mounted transmitter. This cable, which is available from Heinrichs
Messtechnik, has five twisted pairs, each of which has a foil shield, tinned copper mesh and filler cord. The
tinned copper meshes are installed in the “shield” terminal in both the sensor and transmitter. All 5 cable pairs
are shielded by a further tinned copper wire mesh. This external cable shield is connected to the housing via a
dedicated EMC cable fitting, thus ensuring optimum noise immunity.
Schirm / shield
10
9
8
5
7
6
4
3
2
1
-
-
-
-
-
-
-
-
-
-
rosa / pink
grau / grey
schwarz / black
violett / violett
blau / blue
rot / red
gelb / yellow
grün / green
weiß / white
braun / brown
-
-
-
-
-
-
-
-
-
-
Schirm / shield
10
9
8
5
7
6
4
3
2
1
rosa / pink
grau / grey
schwarz / black
violett / violett
blau / blue
rot / red
gelb / yellow
grün / green
weiß / white
braun / brown
Image 2: Heinrichs standard cable: SLI2Y (SP) CY 5 x 2 x 0.5
The operator is to comply in all cases with the applicable installation regulations such as EN 60079-14
“Electrical apparatus for explosive gas atmospheres- Part 14: Electrical installations in hazardous areas”.
Applicable guidelines pertaining to the interconnection of intrinsically safe circuits must also be observed.
