GB1347991A - Rain or storm water tank - Google Patents

Abstract

1347991 Stormwater separating tanks for sewage systems G NUSSBAUM 10 March 1971 6530/71 Heading E1C A stormwater separating tank, for insertion in a sewage system between a sewer and a purification plant, comprises a circular or polygonal chamber such that the sewage can circulate around inside the chamber, means for bypassing the chamber for small rates of sewage flow, and an arrangement whereby stormwater enters the chamber in a circumferential direction to cause circulation within the chamber whereby the chamber walls are scoured and solids are caused to settle towards the centre of the tank, so that where overflow arrangements are provided the overflow will be substantially uncontaminated. In Fig. 1a, a circular tank 10 having a tangential inlet pipe or pipes 11 is shown, a groove being provided in the floor of the tank leading directly from the inlet pipe to an outlet pipe 14 for small rates of flow. A similar arrangement (Fig. 1b, not shown) may be provided in a tank of hexagonal shape. In another embodiment (Fig. 1c, not shown) the tank is octagonal and has a raised central floor portion provided with grooves (15) to assist in the separating of the solids from the liquids prior to discharge of the sewage to the outlet pipe (14). In a modification (Fig. 2a, not shown) an overflow (26) is provided in the upper portion of the tank. Fig. 2b also discloses this overflow 26 and associated overflow outlet pipe 25, the by-pass 27 between inlet pipe 21 and the outlet pipe 24 to the purification plant being external to the tank in this embodiment. In a similar embodiment (Fig. 2c, not shown) the by-pass is also external but leads beneath the tank to the point of attachment of the outlet pipe to the centre of the tank bottom. By-passing of the sewage may alternatively be provided by sills (35, Figs. 3a-3d, not shown). A number of stormwater reservoirs may by this means be connected either in series or parallel (Figs 4a, 4b respectively, not shown). In the embodiment of Fig. 5a, an extension basin 50a is provided, separated from a polygonal circulating chamber 50 by baffles 50b, overflow and by-pass arrangements 56, 58 being provided. In further embodiments (Figs. 5b-5d, 6, 7, not shown) modified extension and multi-tank arrangements are disclosed.