GRAVITY SEWER DEVICE - SELF-FLUSHING INVERTED SIPHONS, METHOD OF OVERCOMING WATERCOURSES OR SIMILAR UNDERGROUND OBSTACLES AND USE OF THIS DEVICE

摘要

The invention relates to a gravity sewer device comprising a self-flushing weir forming a section of gravity sewer that crosses under a watercourse or similar underground obstruction. A self-flushing weir according to the present invention forming a section of gravity sewer which crosses under a watercourse or similar underground obstruction is shown graphically in Figure 2 and compared with the conventional weir design in Figure 1, comprising one or more inlet chambers 9 connected to a (downstream) descending leg 12 of the sewer pipe, a crossing 13, an (upstream) ascensing leg 14 of the sewer pipe and an outlet shaft 7, wherein an automatic flushing bell 17 or 20 is located in the inlet chamber 9. The automatic flushing bell 17 (alternatively in embodiment 20), which includes a siphon conduit 15 and a siphon conduit 16 deaeration, provides a periodic alternation of two phases, accumulation and overflow, wherein the water level in the accumulation inlet chamber 9 varies between HI and H2, the filling rate (or flow rate) is Q(0), and the overflow rate (or flow rate) is Q(l). The level difference H2-H1 is the driving energy of the overflow, it has to be chosen with respect to the length of the header and the local resistances on the pipe so that the effective velocity v(ef) does not fall below 1.0 m.s-1, an indicative value for the correlation calculation can be considered H2-H1=0.5 m.