Discharge measurement in circular sewer

The Sector Venturi is a novel design to determine discharge in sewers. Its main features are simplicity, accuracy of ±5%, and low cost. Further, the modular limit is comparable to standard flumes, and the capacity is equal to similar devices. Based on an optimization procedure, the best geometry was retained. The Sector Venturi is characterized by a ring of variable diameter, in which two sharp-crested sectors are attached. When mounting the Sector Venturi, the ring is expanded to match with the pipe section. The sector elements are sharp crested and have a notch at the invert. The principle of discharge measurement involves critical flow across a constriction. To stabilize the depth reading, holes are drilled in the sectors and two symmetrically arranged containers allow reading of the total head. The discharge is determined with a rating curve. One particular feature of the Sector Venturi is its insensitivity to clogging. As outlined, there are several disadvantages when compared with the pier-shaped Mobile Venturi Flume, but these do not detract from a useful means of discharge measurements in sewage.