Proline t-mass 65F, 65I
12
Hauser
Thermal insulation
When the gas is very humid or saturated with water (eg. Biogas) the pipeline and flowmeter body should be
insulated to prevent water droplets condensing on the pipe wall and/or flow transducer. In extreme cases of
moisture and temperature variation, it may be advisable to provide trace heating of the pipework and/or sensor
body.
a0005122
a = Maximum insulation height for the flanged version
b = Maximum insulation height for the insertion version
Inlet and outlet runs
The sensitivity of the thermal dispersion principle to low flow rates means the flowmeter can also be sensitive
to internal disturbances in the flowing gas stream (e.g. swirl) especially in the larger pipe diameters (
≥
DN 150
(
≥
6")).
As a general rule, the installed thermal flow sensor should always be installed as far away as possible from any
flow disturbances. See ISO14511 for further information.
Process components or pipework configuration
When disturbances (e. g. pipe elbows, reducers, valves, T-pieces etc.) are located upstream of the thermal
meter, precautions must be taken to minimise any effects on the measuring performance.
The figure on the following page illustrates the minimum recommended inlet and outlet runs expressed in mul-
tiples of the pipe diameter, longer lengths should always be used if they are available in the metering run.
Regardless of any other consideration, the minimum recommendations for inlet and outlet runs on either side
of the sensor are:
Inlet runs:
Minimum 15 x Dia for the flanged version (65F)
Minimum 20 x Dia for the insertion version (65I)
Outlet runs:
Minimum 2 x Dia for the flanged version (65F)
Minimum 5 x Dia for the insertion version (65I)
Note!
• These are minimum values, increasing these dimensions will often improve the flowmeter perfomance.
• Where two or more disturbances are located upstream of the meter, the longest recommended upstream
pipe run is to be observed as an absolute minimum.
• It is always recomended to install control valves downstream of the flowmeter.
• For very light gases such as Helium and Hydrogen all upstream distances should be doubled.
a
b
a
b
