FIRST FLUSH DIVERTER
for In Ground Rainwater Tanks
First Flush
Rainwater quality from different roof catchment is a function of the type of roof material, climate conditions and surrounding environment. The particularly true of the roof is subject to the oxidising affects of sun and air borne pollutants. The most common type of roofing material used for rain catchment in Australia is galvanised metal that has been painted or enamelled with a non-other materials include slate, terra cotta tiles or concrete. Asphalt shingles are adequate but produce less water in summer and are harder to keep clean. Beware of the "modern" shingles that contain moss inhibitors if you plan to drink or bath in the water. Water collected from cedar roofs is acidic for plants and is impractical for indoor use.
Over time leaves, dirt, animal drops, salt and other pollution build up on your roo and gutters. Without a first flush system this will be washed off the roof and directly into your rainwater tanks causing the water to become dirty and possibly dangerous.
Sediment and pollution in rainwater tank can also lead to:
1) Damage to pumps, washing machines and other appliances which connected to the tank;
2) Blocked sprinklers;
3) Excessive wear and shortened life on tap washers;
4) Bacteria and algae growth in your rainwater tanks.
RAINDOG first flush diverter for in ground rainwater tanks is designed for harvesting better quality and cleaner rainwater for your in ground rainwater tanks.
It has the functions:
1) Automatically diverts between first runoff roof rainwater into stormwater drain and cleaner rainwater into in ground rainwater tank without electrical or battery power;
2) The amount of first flush to be diverted is adjustable by changing device’s “volume control sticks”. Without any stick, it refers any roof area around 50 square meters, with marked “100m2”, it refers around 100 square meters roof area and so on up to around 300 square meters roof area (Australian Government recommendation: “First flush diverters are typically sized to divert about 10L per 50 square meters of roof area”).
3) It can stop diverting first flush when two-rain gap is less than two days (depending on local humidity) to save rainwater from unnecessary diverting first flush;
4) No regular maintenance is required.
It provides the best solutions for all kind of in ground rainwater tanks with right diverting system.
How does it work?
The Chamber
First run-off rainwater from the roof and gutters comes into the device inlet (1). About 1/20 of first flush will be diverted into the chamber (2) through its inlet (3) which is adjustable with different volume control sticks (3-a) according to roof area. There is a filter screen at the chamber inlet (3) to prevent certain sized dirt, debris and leaves getting into the chamber. In the mean time, the rest of first flush will be diverted into storm water drain through the device’s outlet A (4) while the unbalanced tipping valve (5) is in open position. The volume control stick diverts first flush into two parts. One goes to storm water drain and the other goes to the chamber in which they are controlled by the stick. When the chamber is full, the valve (5) will shut the pass ways of outlet A (4) and the chamber. Now first flush is completed and clean rainwater starts delivering into the tank through device’s outlet B (6).
The Unbalanced Tipping Valve
The unbalanced tipping valve (5) determines whether rainwater goes to storm water drain or the tank, also controls self-clean valve (7). The another important function of this valve is that the valve can hold certain amount of rainwater to keep its closed position. When rainwater within the valve is evaporated, the balance has broken, then the valve will open the pass way to storm water drain ready for next first flush operation. The period of time is depending on the local humidity, roughly two days. This will system a “break” from first flush when time between two0- rain is less two days thus this can save more rainwater from unnecessary first flush.
The Self-clean Valve
The self-clean valve (7) inside the chamber opens when valve (5) is shut. So all the dirt will be cleaned off when the chamber is emptied through the outlet A (4).
Installation
RAINDOG first flush diverter for in ground rainwater tanks can installed in ground (levelled with in ground rainwater tank’s inlet) and also can be installed at high side ground and above ground.
1. What is the roof area in square meters;
2. To select one volume control stick which is suitable for the roof area and slide it down into the chamber inlet (3);
3. To select a location where the device is going to be installed (normally, it closes to the tank’s inlet);
4. To make sure that the device’s outlet A (4) is higher than tank’s overflow end point;
5. According to this height to make a solid levelled base where the device is sit on;
6. To connect down pipe to device’s inlet, device’s outlet B tank’s inlet, device’s outlet A to storm water drain pipe line; (refer marks on the device, all connection are use 100mm pipe);
7. The device is 450mm height from bottom to top of lid. If it is needed using our 600mm rising neck to make a total height 830mm to level ground surface;
Note:
1. The lid approaches 1.6Kg/cm2 Class C load rating. It can be installed in driveway.
2. If the storm water drainage is higher than in ground rainwater tank or you want to install the device above ground for some reason, the only one thing should remember is that the device’s outlet to storm water drain is higher than storm water drain at curb.
PHONE 61-412358388
EMAIL admin@raindog.com.au