Self Flushing Siphon

The GNA HYDROFLUSH self-flushing or "closing syphon" is designed to clean small 200-400 mm (6-12") diameter sewers. This device's flushing intensity flows from as little as 5 l/s (80 gpm) up to 31 l/s (500 gpm).


  • Works with extremely low inlet flows 
  • Rain, domestic or industrial water can be used to activate the system. 
  • Flushing action activated by a drop of water
  • Will remove deposited material in sewers
  • Can be used for odor control
  • Compact, simple and reliable operation
  • No operating or maintenance expenses
  • Easy to install
  • Stainless steel construction

Principles of Operation

  • Siphon Flushing
  • Maximum level is achieved and syphon is primed
  • Siphon action generates flushing wave
  • Siphoning action terminated
  • Back-washing inlet to remove debris
  • Standby position

Before Installation

After Installation

The HYDROFLUSH system of cleaning small diameter sewers together with the well known GNA Hydroself flushing gate system provides a complete range of automatic flushing system for all sewers, box culverts and basins without any external energy supply.

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