II. Sewer Network and Facilities Topic II. 10 II. Sewer Network and Facilities Topic II. 10. Drop Manholes: Kinds and Structures. Inverted Siphons Purpose For overcoming terrain obstacles by the sewer For overcoming underground obstacles by the sewer For sewers at steep terrain For sewer branches joining deeper collectors For buildings sewer joining deep street collectors For sewer outlets under the receiving water level

Kinds of Drop Manholes I. According to the drop height With low drop height (h < 6 m) With high drop height (h > 6 m) II. According to the flow energy dissipation Shaft type (with or without stilling pool and/or baffles) Chute type (with stilling pool) With bar racks (without stilling pool) With baffles (with or without stilling pool) With flow split and mutual energy dissipation

Schemes of Drop Manholes Structures Kinds of Drop Manholes Schemes of Drop Manholes Structures a - chute type without stilling pool; б - chute type with stilling pool; b - with baffle and stilling pool; г - shaft type without stilling pool; д - shaft type with stilling pool; e - shaft type with declined baffles; ж - shaft type with horizontal baffles

Shaft type without stilling pool and for low drops Kinds of Drop Manholes Shaft type without stilling pool and for low drops

Kinds of Drop Manholes Shaft type with horizontal baffles (scheme) Kinds of Drop Manholes Shaft type with horizontal baffles (scheme) Chute type with stilling pool

Drop Manhole with a Baffle and Stilling pool Kinds of Drop Manholes Drop Manhole with a Baffle and Stilling pool

Kinds of Drop Manholes Shaft Type Drop Manhole for High Drops 1 - open channel to the stilling pool 2 - vertical shaft pipe 3 - inlet sewer pipe 4 - manhole 5 - installation opening 6 - cover plate 7 - stairs 8 - intermediate stage 9 - cunette platform

Inverted Siphons I. Purpose II. Main Parts For overcoming terrain obstacles by the sewer - with pressure pipes For overcoming underground obstacles by the sewer - with II. Main Parts Inlet chamber (with sluice gates or stop valves) Outlet chamber (without sluice gates or stop valves) Pressure pipes For dry weather flow For wet weather flow Emergency bypass pipe

Inverted Siphons Principal Scheme

Inverted Siphon (Scheme of Main Parts)

Inverted Siphon