Clogging cause – soil ingestion

This can occur after the irrigation water is stopped and the residual water in the drip laterals drains. When this occurs, a vacuum is created around the emitters at higher elevations. However, as the irrigation system has been functioning, there is no air around the dripper (when buried) to meet this suction. As a result, soil particles can be sucked back into the emitter itself.

Several approaches are available to reduce the risk of clogging from soil ingestion:

  • Install vacuum relief valves to let air flow into the drip lines as drainage occurs.

  • Consider using an emitter with a slit outlet that closes when the pressure is off to keep out any
    external contaminants.

  • If a slit outlet is not available, the use of anti-siphon (AS) or no-drain (ND) drippers helps prevent suck-back.




AS System

Use anti-siphon (AS) drippers in conditions where risk of soil ingestion at shut-off is high. When there is negative pressure in the hose (i.e. a vacuum caused at system shut-off), the AS membrane lowers against the inlet filters, which in turn slows the reverse of water.

Application: SDI, or on surface with sandy soil.

Water from the pipe slowly drains reducing the suction effect of soil particles into the dripper at system shut down.



ND System

Use no-drain (ND) where you have pulse irrigation – short and frequent irrigation cycles where the water needs to stay in the tube during shut-off. When the pressure drops below specified pressure, the ND dripper seals, keeping the water in the tube, ready for the next irrigation cycle.

Application: Pulse Irrigation.

Pipe remains filled with water at system shut down. 


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