VEGA VEGASON 71 - D - Manual (Page 29)

VEGASON 71 - D 29
7 Output results
7.6.4 Rectangular weir with throat
With sharp weir edge and throat
Weir edge
K = 6290
Calculation of the actual flow value (Q)
The following formula can be used for calculation of the
actual flow for liquid levels < h
max
… > h
min
.
Q = B • K • h 1,5
Q in m 3 /h
B in m
h in m
Assumed values for a calculation example
B =
0,4 m
K = 6290
h = 0,13 m
Calculation example
Q =
0,4 • 6290 • 0,13 1,5 = 117,9 m 3 /h
Programming acc. to calculation example
Q
max
= 117,9 m 3 /h
- Mode 0 - 82 , flow = 0118
- Mode 0 - 83 , multiplier = 0
- Mode 0 - 84 , time unit = 3
Explanation:
Q
max
= max. flow in m 3 /h
B = weir width in mm or m
K = throat specific factor for above rectangular weir = 6290
h
max
= max. weir height in mm or m
k = thickness of the weir in mm
3 - 4 x h
max
2 - 3 x h
max
≥
2 x h
max B
45
°
Selection of the actual flow (Q)
Flow schedule for usual rectangular weir
B Q
max
h
max
Q
min
h
min
in mm in m 3 /h in mm in m 3 /h in mm
200 52,3 120 18,5 60
300 109,6 150 27,7 60
400 295,8 240 37,0 60
500 441,2 270 46,2 60
600 620,0 300 55,5 60
800 1519 450 73,9 60
1000 2923 600 92,4 60
1500 6128 750 138,7 60
2000 13535 1050 184,9 60
3000 34666 1500 277,3 60
If a rectangular weir acc. to above value is used, the value
for Q
max
can be taken out of the respective column and can
be used for programming of mode 0 - 82 … 0 - 84 .
Programming acc. to selection Q
max
= 13535 m 3 /h
- Mode 0 - 82 , flow = 1353
- Mode 0 - 83 , multiplier = 1
- Mode 0 - 84 , time unit = 3
k
≈
3 mm
k
≈
3 mm
h
max
or