Intewa PURAIN 150-S User manual

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PURAIN 150-S versions
Hydraulic jump rainwater filter
German engineering
High-efficiency, self-cleaning, patented
Instruction and Installation Guide
www.intewa.de

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Contents
1. Introduction.............................................................................................................2
2. Technology & Scope of Application......................................................................2
3. Accessories.............................................................................................................3
4Technical data.........................................................................................................5
5. General installation instructions ...........................................................................5
6. Maintenance............................................................................................................8
7. Warranty / Contact..................................................................................................9
VERSIONS AVAILABLE
DESCRIPTION
Part No
PR150-S
–for standard in-tank/cistern installation (incl skimmers)
210143
PR150-S oSK
–for out-of tank or in-ground installation (has no skimmers)
210149
PR150-M
–for monsoon/high flow use. For in-tank/cistern installation
(contains no internal baffle & incl skimmers)
210176
PR150-M oSK
- for out-of tank or in-ground installation (has no skimmers)
210178
PR150/200-S
–specially adapted for discharge pipes of size DN200
210147

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1. Introduction
Updated technical data, scope of application and basic dimensioning are available at:
https://za.intewa.net/en/products/purain/technology/
Various filter tests and reports are available for download at:
https://za.intewa.net/en/products/purain/downloads/
2. Technology and Scope of Application
Thank you for your INTEWA product purchase.
Your PURAIN Rainwater filter provides optimum rainwater quality in your tank.
PURAIN rainwater filters (also known as Hydraulic-Jump filters) deliver high performance in the
filtering of rainwater and this hydraulic-jump technology means that the filter cleans itself
automatically.
During the design phase, INTEWA studied world rainfall data. Purain filters have been designed to
collect rainwater especially from “light” rainfall events and use the “heavy” events for self-cleaning.
This efficient design is important, as studies have shown that 97% of all world rainfall comes from
“light events”, leaving only 3% of rainfall coming from “heavy events”.
+/- 97% of world rainfall is termed "light events" - (measured as less than .6mm in 5 minutes)
+/- 3% of world rainfall is termed "heavy events" - (measured as more than .6mm in 5 minutes)
As most other filters cannot adequately collect light events without wastage they end up with
collection efficiencies of between only 60 - 70% –and waste large quantities of valuable rainwater.
By using this little-known knowledge, INTEWA has been able to design the world's first "hydraulic
jump" self-cleaning rainwater filter, offering the highest water collection efficiency of any filter
available. Rain filtering is all about Quality & Quantity!
In the design, the flow of water is substantially altered due to a height drop, from a sub-critical to a
super-critical flow.At the bottom of the collection chamber, the waterflowalters again to a subcritical
flow in a process now commonly known as a hydraulic jump. This resulting increase in water power
is similar to a strong eddy and forces any impurities into the overflow to be washed away to waste.
Independently tested by Germany’s Siegen University, the PR-150-S is rated as one of the most
efficient rainwater filters in the world - at 98% collection efficiency. This means that for every 100

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litres of rain falling on your roof, your filter will collect 98 litres of it.
PURAIN rainwater filters are designed to filter rainwater coming off roofing made from clay brick,
shales, tiles, metal, glass or concrete stone. Different sized PURAIN models can be installed
covering roof areas up to 15,000 m².
PR-150-S models offer the following features:
•High collection efficiency - collecting 98% of all rainfall falling on your roof;
•Efficient filtering of roof areas up to 750m2;
•Designed for connection to DN150 discharge piping;
•Built-in overflow skimmer to constantly clean debris floating on the tank water (PR-150-S only);
•Hydraulic jump design –self-cleaning feature;
•Minimal maintenance required;
•Generally, only one filter needed for each building/project –even if multiple tanks are used;
•0.8mm removable stainless-steel filter strainer;
•European manufacture –sturdy injection-molding that will outlast the life of LDPE tanks;
Above: Integrated skimmers on PR150-S version Above: PR150-S versions feature
clean the surface of the tank water each time a removable 0.8mm stainless-steel
there is an overflow = better water quality trapezoidal filter grid
3. Accessories
Cover for PR-150-S and PR-150-200-S incl. chamber connection
The quick-lock chamber connection fitting allows for the
PF 300-S chamber extension or PF 300-C cap
accessories to be used
The PR-150-C lid is used when in-ground or externally
wall mounting the PR-150-S and PR-150-S o.SK
versions.

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PF300-150 Calmer is an integral component to “best practice”
rainwater collection ensuring that incoming rainwater to the
tank is calmed, ensuring sediment stirring is kept at a minimum
PR-RSDS-150-200 back-flushing nozzle for PR-150-S and
PR-150-S o.SK
For large filters, we recommend the back-flushing nozzles to
minimize the intervals of manual maintenance. The back-
flushing nozzle is installed in PURAIN rainwater filters behind
the sieve. The mounting components required for this are
included. The water required for back-flushing can either be
supplied manually through a tap or automatically via a time-
controlled solenoid valve.
PR-RSDS-150-200 back-flushing nozzle for PR-150-M
PR150-M without baffle means there is no anchoring point to connect the back-flush nozzle.
Therefore, it is recommended to drill a hole in the side of the filter as shown and adapt the sprayer
connection arm angle and fix to this position
**See separate PR RSDS-150-200 back flush Installation Manual available from your country
distributor
Accessories Codes
Description
Part No.
Code
Cover for PR-150-S (all models)
210148
PR-150-C
PLURAFIT chamber extension
300005
PF 300-S
PLURAFIT cap
300010
PF 300-C
Back-flushing nozzle for PR-150-S (all models)
210170
PR-RSDS-150-200

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4. Technical data
As a general rule, the choice of a PURAIN rainwater filter is made based on the diameter of the
rainwater collecting pipe stipulated by the building architect or water engineer e.g. DN150 (160mm)
= PR-150-S.
If the diameter of the planned collecting pipe is not known, then you can refer to the following table.
It gives an overview of the dimensions of these rain water connection pipes, as per DIN 1986, with
measured rainfall yield indicator of r = 300 l/s ha and a slope of 1.5%. The discharge coefficient
indicates by what factor the amount of rain discharged may be reduced, due to the type of roof used
(considering water fall, velocity, evaporation, overflow, etc).
•Discharge coefficient 1 = theoretical value
•Discharge coefficient 0.8 = inclined roof
•Discharge coefficient 0,5 = extensively grassed roof
Flow rate with 1,5 %
slope DIN 1986
Discharge
coefficient = 1,0
Discharge
coefficient = 0,8
[average used]
Discharge
coefficient = 0,5
DN100
5,7 [l/s]
190 m²
238 m²
380 m²
DN150
16,9 [l/s]
564 m²
705 m²
1.128 m²
DN200
36,3 [l/s]
1.210 m²
1.513 m²
2.420 m²
DN300
106,1 [l/s]
3.537 m²
4.422 m²
7.074 m²
DN400
226,8 [l/s]
7.560 m²
9.450 m²
15.120 m²

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5. General installation instructions
IN-TANK INSTALLATION
•The filter is best installed inside the tank, if possible,under the inspection lid for mostefficient
functioning (PR150-S version);
•The filter must be installed with a slope of 2 –5
% from inflow to outflow side;
•When drilling your pipe entry/exit holes in the
tank wall be aware of the 15cm offset between
in-flow and out-flow level;
•160mm pipe clamps should be used (attached to
the roof of the tank) in order to support long
sections of pipe from sagging due to the filter’s
weight;
•In below ground installations, at least 150 cm of
horizontal pipe should be inserted on the inflow
side of the filter to calm the water flow before it
enters the filter, as water gains velocity as it falls
from roof height to the underground tank and this
speed may reduce the filter’s efficiency;
•For proper skimming of the surface water the PR-150-S must be installed without any lateral
tilt (filter sides must be level);
•A separate tank overflow does not need to be installed, even if multiple tanks are utilized -
the filter overflow handles this;
•Accessibility to the filter is important for cleaning and maintenance of the stainless-steel filter
strainer;
•A ‘P’ trap can be installed on the overflow side of the filter to prevent possible smells entering
the tank from the storm water connection;
•Back-flush kit PR-RSDS-150-200 should be installed to reduce maintenance further (see
“accessories”);
•A water intake calmer (PF300-100) is located on the floor of the tank, below the filter,
preventing the sediment layer from being disturbed by incoming water (see “accessories”);
•It is best practice to use a floating suction filter on the pump intake line rather than draw
water from the outlet fitting at the bottom of the tank as this stirs up sediment and will
eventually lead to the fouling of internal flush valves and sprinkler heads (see “accessories”).

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WALL-MOUNT INSTALLATION
Should it not be possible to mount the PR-150-S inside the tank, it can be mounted above the tank
(see below illustration). The version used for wall mounting is PR-150-S oSK.
NOTE: An out-of-tank installation of
this nature requires both PR-150-C
cover and PF-300-C cap to keep
additional dust and debris from
entering the collection chamber.
NOTE: This kind of installation
requires a PR-150-S o.SK version
filter because it comes without
skimmer, unnecessary outside of the
tank.
NOTE: Take into consideration the
overflow pipe levels to ensure the
overflow is installed correctly. Ensure
the mounting brackets are capable of
holding the filter’s weight when filled
with water (in case of blockage).
NO holes may be drilled into the body of the filter when wall mounting. The filter must rest on
correctlydesigned and installed brackets –tech drawings are available from your country distributor.

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SUB-SURFACE INSTALLATION
PR-150-S oSK version can also be in-ground mounted.
NOTE: The unit is ribbed and made from
sturdy HDPE. If the earth is well
compacted around the filter and a man-
hole is used, a carrying capacity of
several tonnes can be realised.
NOTE: PR150-S oSK version can also be
sub surface mounted within a purpose-
built sump.
NOTE: In below ground installations, at
least 150 cm of horizontal pipe should be
inserted on the inflow side of the filter to
calm the water flow before it enters the
filter, as water gains velocity as it falls
from the roof height to the underground
tank and this speed may reduce the filter’s
efficiency;
6. Maintenance
Your filter requires much less maintenance than other rainwater filters due to the hydraulic jump
design and the stainless-steel filter strainer design.
The filter should be checked 2-3 times a year for contaminants that may become caught in the
slotted trapezoidal sieve. Dirt and leaves found in the discharge area need not be removed because
they will be flushed out through the overflow with the next heavy rainfall. If water has accumulated
in the discharge area then the stainless-steel filter strainer may be blocked, but this is effectively
cleaned in a few seconds by using a hose or a high-pressure cleaner simply directed at the strainer.
By doing this the deposits, between the 0.8mm stainless filter strainer, can also be effectively
removed.
Alternatively, the filter strainer can be removed and cleaned manually. In doing so, it is important to
clean the filter collection area with a high-pressure cleaner to flush all dirt out through the emergency
overflow before removing the strainer. In this way, the clean strainer can be re-installed without dirt
and sludge fouling the lateral support guides to ensure a perfect fit.
By installing accessory PR-RSDS-150-200 back-flush kit then visual checks can be lowered to 2
times per year. In this case, external cleaning via the back-flush kit should also be done 2-3 times
per year –either at the change of seasons or before heavier rain periods are expected.

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7. Warranty / Contact
All INTEWA products carry a German backed 24 month warranty against faulty manufacture.
INTEWA or its agents will not be responsible for damage or poor performance of the products due
to faulty or poor installation.
Any changes to design, modification or addition of non-specified parts, willvoid this warranty. Always
retain your purchase invoice during the warrant period.
For any queries, spare parts or orders please contact your local INTEWA dealer, or this office in
South Africa, at pure[email protected] or [email protected]
www.purerain.co.za

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© INTEWA GmbH
Version: 0.3rsa
Subject to technical changes.