HydrINS 2 / HydrINS 2 Mini flow meter
Installation Manual
Page 20 / 79
Disturbances
Upstream straight length to be observed (multiple of
the internal diameter DI)
Measurement to the
centre
Measurement to 1/8th
90° connection or elbow
25
50
Convergent cone (18 to 36°)
10
30
Divergent cone (14 to 28°)
25
55
Open gate valve
15
30
Open butterfly valve
25
45
Table 1: Upstream disturbance-free straight lengths to be observed
4.2
Velocity limits for measurement
Maximum velocities must be observed in order to prevent irreversible damage to the sensor. The
following charts show the maximum velocity applicable to the probe according to the chosen sensor
diameter and position. These values are provided as an indication. They are used when programming
the flow meter in Winfluid in the form of the
maximum flow rate tolerated by the probe
(refer to
the
HydrINS 2 / HydrINS 2 Mini flow meter acquisition programming manual
)
The flow rate is calculated based on a perfectly developed flow profile. Refer to the ISO 7145-1982
standard.
Figure 11: Maximum velocity for different pipe internal diameters
The creation of a velocity profile is used to refine the insertion factor and profile factor values (refer
to the
HydrINS 2 / HydrINS 2 Mini flow meter acquisition programming manual
). The order of
magnitude of the maximum velocities to be observed are indicated on the chart below.