AU2007100365A4

AU2007100365A4 - A Fixed Volume First Flush Fluid Diverter

Info

Publication number: AU2007100365A4
Application number: AU2007100365A
Authority: AU
Inventors: Jonathan Keren-Black
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-04
Filing date: 2007-05-04
Publication date: 2007-06-07
Anticipated expiration: 2015-05-04

Description

DESCRIPTION

0 The principle of operation of the apparatus is that an initial volume of contaminated rainwater flows onto the baffle and fills the flush tank. The baffle or similar passive device spreads the water flow and minimises the stirring effect from further rainfall, 0allowing the contamination to settle. Once the water level rises to the outlet, it flows down it and on to the storage. No water is released on a continuous basis, but only as required at appropriate times. Experience has shown that an automated mechanical en3 valve opening either every 24 hours or when the rain has ceased allows all rainwater, contamination and sediment to be released. Such valve or regulator may be located at the flush tank or away from it provided that there is fluid communication between the two parts.

The rainwater flush tank may be a purpose made tank or a conventional cylindrical downpipe with an outlet pipe, a baffle device and a drain on the lower end of the flush tank. Provision may be made for draining/cleaning/inspection of the tank with a sealed cap, which could be combined with the drain outlet.

The capacity of the flush tank in the various embodiments of the invention can be varied to adjust the amount of roof area feeding into the flush tank. This amount will depend upon the type of system in which the flush tank is used, and on the local conditions and pollution levels expected.

The flush tank and other parts can be fabricated from metal or unplasticised polyvinylchloride which are typically used in plumbing installations, or materials such as HDPE or the like which may be considered to be environmentally preferable.

So that the invention can be fully understood, an example of the separating apparatus will now be described with reference to the accompanying drawings (?Operation Schematic? drawing) Explanation of operation of First Flush Diverter 2 1) The apparatus is attached to the wall beneath a downpipe 0 O 2) Rainfall falls [via coarse leaf filter and fine filter 3) The flow falls onto baffle plate B 1 and back along B2 (F) 4) The water falls to flush tank outside outlet pipe (G) The outlet is kept normally closed by a valve.

06) The water starts to fill the flush tank K, L) 7) Eventually, the water level in the flush tank rises to top level (M) 8) From this point, further rainfall causes overflow into outlet (G) O9) When outlet is opened by valve, the flush tank is emptied.

The apparatus is ready to recommence from the beginning.

The amount of water held in the flush tank should be calculated prior to manufacture/installation, and can be adjusted by varying the flush tank volume. This could be achieved by varying the length of the piping making up the flush tank and/or using piping or a vessel of a different diameter. Using piping of 90, 110, 150, 225 or 300 mm diameter, flush tank volumes of 5 to 100 litres can be obtained.

Over the years, various tests have been conducted to optimise the amount of water which should be flushed over a given plan roof area One such series of tests suggests only 0. lmm/m2 is required but this is very much less than the generally accepted figure of between 0.5mm and 2.0mm/m2 depending on pollution levels i.e.

taking the mid-point in this range of lmm/m2, this equates to 1 litre per m2 of plan roof catchment area.

A typical downpipe may collect from 50 m2 of roof area, requiring 25-100 litres flush tank capacity

Claims

1. Apparatus which, when positioned to intercept rainwater flowing from a roof, prevents an initial flow of contaminated rainwater from entering a store tank, said apparatus comprising a rainwater flush tank arranged for connection in the 0rainwater flow path to intercept the flow of rainwater flowing directly or via a feed pipe into a store tank; said flush tank including a baffle device, an outlet and a drain, Narranged so that when the flush tank is full to the designed level, the incoming water Ocauses water to exit the flush tank via the outlet and into the store tank. The tank is drained from time to time by manual, mechanical or automatic means so that it is ready to function once more as a temporary tank for the first new flush. The purpose of the arrangement is to reliably minimise the dust and solid contaminants contained in the first flush of water from being conveyed to the storage.

2. Apparatus as claimed in claim 1 and including regulation of the flow of rainwater from the outlet.

3. Apparatus as claimed in any of the preceding claims, wherein the flow of rainwater from the flush tank is regulated by a valve connected to the rainwater flush tank.

4. Apparatus as claimed in any of the preceding claims and wherein a screen is or screens are provided as part of the apparatus, for the purpose of trapping some of the solid contaminants.

Apparatus as claimed in any of the preceding claims and including a removable cap on the bottom of the flush tank to enable access so that accumulated solid contaminants can be removed.

6. Apparatus as claimed in any of the preceding claims utilising other passive flow control arrangement in place of the baffle to minimise mixing of the first flush and later flow.

7. Apparatus as claimed in any of the preceding claims and including a second storage tank for the contaminated water collected from the initial flow.

8. Apparatus for removing solid contaminants from fluids flowing from a collecting area to storage substantially as herein described with reference to the accompanying drawings.