PULSAR MEASUREMENT
97
Special Devices
Point of Measurement
The transducer must be above the
maximum head P704
by at least the
near
blanking distance P107
.
In the case of a
Palmer Bowlus
flume the point of head measurement
should be
half
the value of
Dim “A” P710
upstream
of the device.
For a
H-Flume
the head measurement is taken at a point
downstream
from
the flume entrance as detailed in the table below:
FLUME SIZE-DIM A
(P710)
POINT OF MEASUREMENT
cm
feet
cm
inches
15.25
0.5
4.7
1.88
23.00
0.75
6.7
2.69
30.05
1.0
9.1
3.63
45.70
1.5
13.5
5.378
61.00
2.0
17.9
7.19
76.20
2.5
22.5
9.00
91.45
3.0
27.2
10.88
137.15
4.5
40.5
16.19
V-notch angle
weirs, the head is measured
upstream
of the weir plate at a
minimum distance of
3 times
maximum head
to ensure the surface of the
liquid is not affected by turbulence or drawdown. See Exponential devices,
above, for further details.
