The GRAF Retention cistern combines rain retention with rainwater harvesting.
To guarantee retention of rainwater, a delayed drain is fitted in the channel with 0.05 to 2.0 l/sec. depending on the customer’s specifications and the retention or harvest volumes. In the event of heavy rainfall, the water level in the cistern rises above the max. water level (short term) and is drained into the channel at delayed speed using a floating drain choke.
This relieves the channel and the treatment works.
The water level can rise to the emergency overflow and sinks slowly back down again after the rain to the long-term max. water level. This rainwater can then be harvested.
We also construct and supply individual, special solutions.
Sizes between 3,750 – 100,000 l with corresponding retention volumes are possible.
This special type of rainwater harvesting is prescribed or subsidised in many communities.
- For rainwater retention
- For rainwater harvesting in the house and garden
- For frost-proof installation in the ground
- The entire tank volume can be used for rainwater retention
- "USA Patent 7854338"
Advantages
Thought-out in every detail
The GRAF Carat underground tank is manufactured using a globally unique injection compression moulding process. The result is a top-class product: resilient, precise-fitting and user-friendly!
Tank installation made easy! The significantly lower weight of GRAF products compared to steel or concrete cisterns makes transport and installation easier.
A combined retention/rainwater utilisation saves up to 50 % drinking water. The water can be used for garden irrigation, cleaning work and in the house also for flushing toilets and washing machines.
With GARANTIA tank systems, the connection seals are already pre-drilled and lip seals are pre-assembled. This saves time and therefore costs during installation.
The GRAF Carat underground tank is manufactured using a globally unique injection compression moulding process. The result is a top-class product: resilient, precise-fitting and user-friendly!
Tank installation made easy! The significantly lower weight of GRAF products compared to steel or concrete cisterns makes transport and installation easier.
A combined retention/rainwater utilisation saves up to 50 % drinking water. The water can be used for garden irrigation, cleaning work and in the house also for flushing toilets and washing machines.
With GARANTIA tank systems, the connection seals are already pre-drilled and lip seals are pre-assembled. This saves time and therefore costs during installation.
Sizing
| Volume [l] | Length [mm] | Width [mm] | Height [mm] | Weight [kg] | order no. | add to enquiry |
|---|---|---|---|---|---|---|
| 3750 | 2280 | 1755 | 2200 | 155 | 370519 | |
| 4800 | 2280 | 1985 | 2430 | 190 | 370520 | |
| 6500 | 2390 | 2190 | 2710 | 225 | 370521 |
calculated size Request for information
