Green technologies for modern settlements with sustainable water and energy management in South Africa.

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The PURAIN rainwater filter

Clean rainwater – lowest maintenance effort

The PURAIN rainwater filter, also known as the hydraulic jump filter, is an innovation for roof areas ranging from 60 m² to over 15.000 m².

The hydraulic jump technology cleans itself automatically. The design model for PURAIN rainwater filters is provided by nature: in almost every stream, you can see how the hydraulic jump functions. The water flows over the stones, smooth and rounded by the action of the water. At the bottom of the drop, the flow changes suddenly and creates turbulance, which is known as a hydraulic jump. This resulting increase in water power transports any impurities over obstacles and away downstream.

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  • Minimal height offset
  • Minimal maintenance intervals 
  • Debris is loosened by immersing the sieve 
  • Self-cleaning due to the hydraulic jump effect
  • Integrated skimmer 
  • Integrated non-return valve 
  • Minimal blocking due to the trapezoidal gap sieve design
  • Optimal cleaning back-wash nozzle, which sprays from under and through the sieve
  • Minimal blocking due to distribution over the total sieve surface 
  • Immediate filtering = no start-up losses 
  • Minimal tilt influence

The following types of PURAIN rainwater filters are available based on your particular need:



PURAIN rainwater filter incl. non-return valve, small animal protection, and skimmer overflow for a single-family house.



PURAIN rainwater filter incl. skimmer overflow and without non-return valve for a single-family house

PURAIN 150-S and PURAIN 150-200-S

PURAIN rainwater filter incl. skimmer overflow for wall and in-tank mounting as well as underground installation.

PURAIN PR-200 to PR-400

PURAIN PR-150 to PR-400:

PURAIN Rainwater filters for large public, commercial, and industrial buildings. This product line is developed for in-tank or separate chamber installation or wall mounting.

PURAIN PR-HD-200 to PR-HD-400

The PURAIN-HD (Heavy Duty) product line is designed for underground installation for trafficable surfaces up to SLW60 (Heavy vehicles, up to 60 Tons). PR-HD rainwater water filters are accessible with conventional manhole lids and rings.

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E-Mail: info@​intewa.​de

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