VEGA VEGAMET 514… D - Manual (Page 29)

VEGAMET 514… D 29
Set-up, parameter adjustment
Max. flow, Q
max
In the term Q
max
(menu point 100 % corresponds to
1000) the following flume specific factors are
considered relating to the adjustment at 100 %
- geometry of the flume
- material of the flume
- flow speed of the flow medium.
The respectively valid values for Q
max
are normally
determined by the manufacturer of the flume.
If the value for Q
max
of an existing flume is not known
this value can taken as a proximity out of the
following schedule or can be calculated.
In addition it is recommended to determine and
observe the frame conditions defined in the literature
to the flow measurement (surface structure of the
flume, flow speed etc.).
Some of the usual flumes are stated in the following
in form of schedules and calculation examples.
Explanations
Q
max
= maximum flow in m 3 /h
Q
min
= minimum flow in m 3 /h
h
max
= maximum damming or overflow height in mm
or m
h
min
= minimum damming or overflow height in mm
or m
B = flume or overflow width in mm or m
K = flume or overflow specific factor
k = thickness of the meas. wall in mm
D = tube diameter in inch
Calculation information
- Liter/sec x 3,6 = m
3 /h
1
- m 3 /h x ––– = liter/sec
3,6
- Example 10 liter/sec ^ 36 m 3 /h
Khafagi-Venturi flume
With rectangular cross section and even canal
bottom
Values for Q
max
B K Q
max
h
max
Q
min
h
min
in mm (Factor) in m 3 /h in mm in m 3 /h in mm
45 605 80 260 4,8 40
120 838 124 280 9,3 50
160 1106 210 330 16,2 60
200 1383 363 410 25,6 70
240 1654 532 470 37,4 80
320 2178 864 540 58,8 90
640 4280 3776 920 383 200
Calculation of Q
max
The following formula can be used for calculation of
the actual flow of liquid levels < h
max
… h
min
.
Presumed values for a calculation example
B = 0,16 m
K = 1106 (derived from B)
h = 0,25 m
Q
max
= K x h 1,5
= 1106 x 0,25 1,5
= 138,2 m 3 /h
B
h
max
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