variations in the head. An Italian design rigid module outlet is shown
in Fig. 9.29. It consists of a cylindrical sleeve with circumferential
apertures (which act as weirs), floating in a fixed outer cylinder. This
ensures a constant head, causing a flow through the apertures irre-
spective of the water level in the distribution canal (Water and
Water Engineering, 1956). The Neyrpic orifice type of rigid module
outlet (French design) is shown in Fig. 9.30; this facilitates the
404 DIVERSION WORKS
Fig. 9.28 Gibb’s type rigid module
Fig. 9.29 Autoregulator (Italian-type rigid module)
