Abstract: A coupling is provided preferably for a vortex valve for use on an outlet pipe in a sewerage system. The coupling comprises an outer component for insertion into a bore of a pipe, and an inner component which is inserted into the outer component, ramp means being provided between the two components, whereby the outer component is expanded to seal against the bore when the inner component is inserted into the outer component so as to engage the second ramp portion. The ramp means comprise first and second portions of different inclinations. The vortex valve has a circumferential inlet which is adjustable.

Abstract: A hydrodynamic treatment device comprises a vessel (2) within which is disposed an inner partition (24). The inner partition (24) divides the interior of the vessel (2) into outer and inner regions (22, 28). Flow enters the vessel (2) through a tangentially oriented inlet (14) and establishes a complex circulating flow within the vessel (2). Settleable solids migrate to the bottom of the vessel (2) and are deposited in a sump (20) through a solids outlet opening (18). Flow enters the inner region (28) through apertures (34) in the inner partition (24), and is discharged through an outlet duct (8). The inner region (28) is closed at its lower end by a frusto-conical, downwardly diverging lower wall (30) which projects outwardly from a central cylindrical wall (26).

Abstract: A separator comprises a gully chamber 2 having inlet and outlet ducts 10, 12. Inlet and outlet housings 20, 22 are disposed within the separator and are connected by a bypass duct 24 which extends around the wall of the chamber 2. Flow enters the chamber through an inlet which is oriented to create a circulating flow. Flow exits from the chamber through an outlet opening provided in the outlet housing 22. The outlet opening is oriented in the direction of the circulating flow so that liquid has to reverse from that flow to pass through the outlet opening. The inlet and outlet housings 20, 22 are made from identical mouldings in which appropriate openings are formed. The bypass duct can be cut to length to position the inlet and outlet housings 20, 22 opposite existing inlet and outlet ducts 10, 12.

Abstract: An overflow chamber (2) is provided for use in a combined sewer overflow. An inlet (12) and an outlet (14) open into the chamber (2) below a screen (20), and an overflow outlet (15) opens into the chamber above the screen. Baffles (26) are provided underneath the screen (20) across the general flow of storm water. In storm conditions, the storm water in the chamber (2) will reach the level of the screen (20), which traps aesthetically offensive material and gross solids, leaving the water to flow through the screen (20) to the overflow outlet (15). The baffles (26) circulate the storm water, and this dislodges material accumulated on the underside of the screen (20) and so helps to prevent blinding of the screen (20) in storm conditions.

Abstract: A screen assembly in which the screen (10) is in the form of an inverted semi-circular trough the foul flow (A) to be screened approaching the underside of the screen so that debris which is filtered falls away from the screen by gravity so minimising blockages and “blinding” of the screen. A helical sweeper (20) is provided to minimise adherence to the screen.

Abstract: A hydrodynamic separator to separate floatable material from a liquid includes a separating vessel having a cylindrical outer wall; an inlet means for introducing the liquid into the vessel in a manner to promote a low energy rotational flow of liquid in the vessel; a base at one end; a top wall at the end opposite the base, the top wall including an axial outlet opening for receiving a flow containing floatable material separated from the liquid flow to the vessel; a flow modifying member provided within the vessel to define with the top wall an annular opening which is spaced from the outer wall; an annular dip plate spaced from the outer wall of the vessel, the dip plate comprising an upper edge spaced from the top wall to define a gap for the flow of liquid containing floatable matter; and an outlet separate from the axial outlet opening in the top wall, comprising a conduit for removing a primary liquid flow from the vessel, which conduit communicates with the interior of the vessel at a substantially ax

Abstract: A vortex valve flow control includes a housing defining a vortex chamber having an inlet for introducing a liquid into the vortex chamber in a manner to promote swirl and an outlet in one axial end of the vortex chamber. The peripheral wall of the of the vortex chamber, which is situated between the two end walls and surrounds the longitudinal axis of the vortex chamber, has a cylindrical cross-section. The distance between the end walls of the vortex chamber is no more larger than the diameter of the vortex chamber. A mounting device mounts a vortex valve flow control in a drainage gully whereby the outlet of the vortex valve communicates with the outlet from the gully. The mounting device includes a first element being securable to an end wall about the outlet opening and a second element mountable in or adjacent the outlet opening of the gully.

Abstract: A separator includes a barrier 53 for retaining solid material thereon and an automatic mechanism for alternately preventing and allowing the flow of liquid to the separator outlet. When the flow is prevented, the liquid backs up through the barrier and washes the solids to a solids collection region 55. In one embodiment, the automatic mechanism includes a pivoted flap 101 and, in another embodiment, a siphon.

Abstract: A hydro-dynamic separator incorporating a solids interceptor (21) upstream of the overflow (19) for intercepting solid matter above a predetermined size entrained in liquid flowing towards the overflow (19), the solids interceptor (21) comprising: (a) a wall (51) terminating in an upper edge (51a) which constitutes a weir in the flow path of liquid flowing to the overflow (19); (b) a barrier (53), extending from the said wall (51) towards a solids collection region (55), said barrier (53) comprising a plurality of openings (69) to permit flow of liquid therethrough but to retain solids, the upper surface of the barrier (53) being disposed such that solids retained on the barrier (53) are washed across the surface by the flow of liquid towards the solids collection region (55); and (c) a liquid collection region (59) beneath the barrier (53) for collecting liquid flowing through the openings (69) in the barrier (53), said liquid collection region (59) being in fluid communication with the overflow (19) of the

Abstract: A vortex valve (40) includes a housing defining a votex chamber(44), the housing having an inlet (46) through which liquid may enter the vortex chamber (44)in a manner to promote swirl within the vortex chamber (44) and an outlet (30) at one axial end of the vortex chamber (44). A wall of the housing is provided with an opening which is normally closed by a closure, this closure (6) being operable between the closed position and an open position in which livid may enter the vortex chamber (44) by-passing the inlet (46). The vortex valve is free from a spring device capable of urging the closure (6) from the open position to the close position. The vortex valve (40) may be provided at the outlet of a gully and is useful in enabling a blockage, which may occur at the inlet (46) of the vortex valve (40), to be by-passed, thereby draining any accumulated liquid in the gully. The blockage may then be removed when the gully is relatively dry.

Abstract: There is disclosed a method of treating liquid carrying suspended solids comprising the following steps: (i) introducing the liquid into a primary treatment vessel (1) and causing agglomeration of solids suspended in the liquid to form flocs which are not settleable to any substantial degree within the time the said liquid is permitted to remain in the primary vessel; (ii) transferring an aqueous component comprising the flocs from the primary treatment vessel (1) to a secondary treatment vessel (5) where a floc of a settleable nature is caused to form; and (iii) permitting said floc to settle under gravity in the secondary vessel (5) and recovering an aqueous component having a substantially reduced concentration of suspended solids relative to the original liquid; wherein the liquid is subjected in the primary vessel to flow patterns, including a low energy circulating flow about a vertical axis of the primary vessel, which provide conditions for the formation of the substantially non-settleable flocs conta