VEGA VEGASON 71 - D - Manual (Page 28)

VEGASON 71 - D 28
7.6.3 Rectangular weir without throat
With sharp weir edge (without throat)
Weir edge
K = 6593
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 = 6593
h = 0,13 m
Calculation example
Q =
0,4 • 6593• 0,13 1,5 = 123,61 m 3 /h
Programming acc. to calculation example
Q
max
= 123,61 m 3 /h
- Mode 0 - 82 , flow = 0124
- Mode 0 - 83 , multiplier = 0
- Mode 0 - 84 , time unit = 3
7 Output results
3 - 4 x h
max
2 - 3 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 54,81 120 19,4 60
400 310,0 240 38,7 60
600 650,0 300 58,1 60
800 1592,0 450 77,5 60
1000 3064,0 600 96,9 60
1500 6423,0 750 145,3 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
= 1592 m 3 /h
- Mode 0 - 82 , flow = 1592
- 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 = 6593
h
max
= max. weir height in mm or m
k = thickness of the weir in mm
k
≈
3 mm
h
max
k
≈
3 mm
or