General Instruction Manual
Installation
Insulation and heat tracing
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IM 01U10B00-00EN-R, 3rd edition, 2018-07-09
6.4 Insulation and heat tracing
6.4.1 Heat tracing
The majority of applications do not require or provide insulation or heat tracing for the
sensor. Product versions with insulation and/or heat tracing are available for specific
technical applications, see applicable General Specifications. Starting with fluid tempera-
tures of approx. 80 °C above or below the ambient temperature, insulating the sensor is
recommended if the goal is to maintain utmost accuracy. These measures are also sensi-
ble with increased requirements for fluid temperature stability.
The sensor is heated by means of heat tracing via a heat transfer fluid running through
stainless steel pipes. The heat transfer fluid is supplied through process connections that
can be selected. The operator is responsible for temperature control of the heat carrier.
Here the specifications for pressure and the temperature of the heat transfer fluid must be
met, see applicable General Specifications.
Heat tracing is only available for the remote type of flow meter and must be selected by
including an appropriate device option when placing the order, see applicable General
Specifications.
WARNING
Risk of overheating the transmitter due to increased ambient temperature
Failure of measuring electronics
▶
Observe the maximum allowable ambient temperature for the transmitter.
▶
Install the transmitter at a sufficient distance from heat sources.
6.4.2 Customer-supplied insulation
For insulation provided by the customer it is important to select a sensor with the appro-
priate design type (remote type, sensor with long neck). The space between upper insula-
tion edge and lower edge of the sensor's terminal box must be at least 40 mm.
Recommended insulation thickness is 80 mm and recommended heat transfer coefficient
0.4 W/m² K.
1
min. 40 mm
Fig. 26:
Customer-supplied insulation
1
Insulation box
DANGER
When installing in hazardous areas, the applicable Explosion Proof Type Manual must be
considered.
