In combine sewer systems - sewage flow and most of rain flows are measured inside a built-in flume with an uncertainty of - 2%. Peak rain discharges are measured using the standard flumes.
In sewer systems under development - a built-in flume serves for a low flow measurement only from a part of waste water producers. When further waste water producers are connected to the sewer system, a built-in flume is removed and a standard flume is used for measurement.
In creeks - for a wide flowrate range and/or with a low backwater requirements.
Combine Flowrate Structure
Significant lowering of expenditure in changing of range of flow volume in sewage in development by measuring culmination rain and minimal sewage flow volume leads to significant improvement in accuracy in measuring of the entire flow volume of waters, prefabrication of combined object lowers the risk of wrong installation.
In the picture is shown Parshall´s flume P3 in shorter version installed in Parshall´s flume P5. Ultrasound scanner is scanning the level of surface and the information is transferred to flow volume end entire flow volume.
Measuring object consist from two measuring flumes. flumes.
Figure shows a shorter version of a Parshall flume P3 which is built-in a P5 flume. Ultrasonic water level and processing unit are used to determine the flowrate. A measuring structure consists of two Parshall flumes when a smaller flume with a specific outflowing section is built-in into a larger one (with a possible dismantling).
Substantial decrease of costs in case of a sewer system development. Measurement of both peak and minimal flowrates results in an substantial increase of accuracy. Prefabrication of combine structure decreases a risk of incorrect installation.
Advantages
Operation stipulations
water temperature 0°C ? 80°C
Free surface flow
Maximum size of suspended solids is limited to 80% of the throat width (dmax = 0.8 w).
Technical and hydraulic data
Type of flume
Discharge range (l/s)
a - b - c *2
Dimensions (cm) (cm)
length, height, width *1
Throat w1/w2
(cm)
m
(kg)
P3/P1
0,26 - 6,2 - 30,5
91,5 / 46,7 / 25,9
7,62 / 2,54
27
P4/P1
0,26 - 6,2 - 97,2
152,4 / 62,0 / 39,7
15,2 / 2,54
54
P4/P2
0,52 - 15,1 - 1044
152,4 / 62,0 / 39,7
15,2 / 5,08
57
P4/P3
0,78 - 54,6 - 94,4
152,4 / 62,0 / 39,7
15,2 / 7,62
73
P5/P1
0,26 - 6,2 - 236
162,6 / 80,0 / 57,5
22,9 / 2,54
87
P5/P2
0,52 - 15,1 - 238
162,6 / 80,0 / 57,5
22,9 / 5,08
90
P5/P3
0,78 - 54,6 - 189
162,6 / 80,0 / 57,5
22,9 / 7,62
98
P6/P1
0,26 - 6,2 - 406
286,7 / 92,5 / 84,5
30,5 / 2,54
153
P6/P2
0,52 - 15,1 - 403
286,7 / 92,5 / 84,5
30,5 / 5,08
156
P6/P3
0,78 - 54,6 - 311
286,7 / 92,5 / 84,5
30,5 / 7,62
173
P6/P4
1,5 - 164 - 369
286,7 / 92,5 / 84,5
0,5 / 15,2
214
P7/P1
0,26 - 6,2 - 597
294,3 / 92,5 / 102,6
45,7 / 2,54
196
P7/P2
0,52 - 15,1 -579
294,3 / 92,5 / 102,6
45,7 / 5,08
199
P7/P3
0,78 - 54,6 - 409
294,3 / 92,5 / 102,6
45,7 / 7,62
211
P7/P4
1,5 - 164 - 420
294,3 / 92,5 / 102,6
45,7 / 15,2
241
P8/P1
0,26 - 6,2 - 797
302 / 92,5 / 120,7
61,0 / 2,54
246
P8/P2
0,52 - 5,1 - 765
302 / 92,5 / 120,7
61,0 / 5,08
249
P8/P3
0,78 - 54,6 - 512
302 / 92,5 / 120,7
61,0 / 7,62
258
P8/P4
1,5 - 164 - 473
302 / 92,5 / 120,7
61,0 / 15,2
290
P9/P1
0,26 - 6,2 - 1200
316,9 / 92,5 / 157,2
91,4 / 2,54
269
P9/P2
0,52 - 15,1 - 1134
316,9 / 92,5 / 157,2
91,4 / 5,08
272
P9/P3
0,748 - 54,6 - 721
316,9 / 92,5 / 157,2
91,4 / 7,62
281
P9/P4
1,5 - 164 - 581
316,9 / 92,5 / 157,2
91,4 / 15,2
298
P9/P5
2,2 - 368 - 522
316,9 / 92,5 / 157,2
91,4 / 22,9
341
*1 construction length of flume / height of inlet section / width of inlet section
*2 Discharge range of built-in flume varies between a/ - b/, maximum discharge of external flume is given by c/. After removing of the built-in flume, the discharge range corresponds with a standard set of Parshall flumes specified before.
Delivery conditions:
Within one month with a possibility of individual change of a discharge range (see Table).
On request we also provide consulting. Moreover, we perform a complete site investigation and a final design.
