ABB SensyMaster FMT430 - Inlet and Outlet Sections

SensyMaster FMT430, FMT450 THERMAL MASS FLOWMETER | OI/FMT430/450-EN REV. B 29
Inlet and outlet sections
The figures below show the recommended inlet and outlet
sections for various installations.
Figure 12: Inlet and outlet sections
Installation
Inlet section
Outlet section
A
Pipe extension
min. 15 × DN
min. 5 x DN
B
Pipe
reduction
min. 15 × DN
C
90° Pipe elbow
min. 20 × DN
D
2 × 90° pipe elbow in one
level
min. 25 × DN
E
2 × 90° pipe elbow in two
levels
min. 40 × DN
F
Turn
-off device
min. 50 × DN
To achieve the specified measuring accuracy, the indicated inlet
and outlet sections are required.
In case of combinations of several inlet-side errors, e.g. valve and
reduction, a longer inlet section must always be taken into
account.
In case of confined spaces at the installation site, the outlet
section can be shortened to 3 × DN. However, reducing the
specified inlet section will reduce the achievable level of
accuracy.
A high repeatability of the measured value is maintained.
In case of insufficient inlet and outlet sections, a special
calibration may be possible. To do this, a detailed alignment is
necessary for individual cases.
The specified inlet and outlet sections must be doubled for
gases with a very low density (hydrogen, helium).