Installation
VA 570 English V1.19
Page 13 of 44
6 Installation
6.1
Pipe/tube requirements
•
Correctly sized gaskets
•
Correct aligned flanges and gaskets
•
Diameter mismatch at the pipe junctions should be avoided but must be less than 1mm.
For further information see ISO 14511
•
Ensure clean pipes after installation
6.2
Inlet / outlet runs
The principle of thermal Mass flow measurement is very sensitive against disturbances. Therefore, it is
necessary to ensure the recommended inlet and outlet runs.
Table Inlet / Outlet runs
Flow obstruction before the measurement
section
Min length
Inlet run (L1)
Min length
Outlet run (L2)
Slight curve
(ellbow < 90°)
12 x D
5 x D
Reduction
(Pipe narrows to the measurement section)
15 x D
5 x D
Expansion
(Pipe expands to the measurement section)
15 x D
5 x D
90° ellbow or T-piece
15 x D
5 x D
2x ellbow á 90°
in einer Ebene
20 x D
5 x D
2x ellbow á 90°
3-dimensional
35 x D
5 x D
Control valve
45 x D
5 x D
15 x D
5 x D
15 x D
5 x D
15 x D
15 x D
5 x D
20 x D
5 x D
35 x D
5 x D
5 x D
45 x D
The values represent the min.lenghts. In case the min. inlet / outlet runs could not be ensured, it must
be expected to get increased or significant deviations of the measurement values.
