Influence of flushing pressure, flushing frequency and flushing time on the service life of a labyrinth-channel emitter

A set of orthogonal experiments using three factors (flushing pressure, flushing frequency, and flushing time) was used to study the anti-clogging performance of a patch-type dentation labyrinth-channel emitter. After irrigation, the change in the emitter discharge was tested, and the discharged particle size distribution was measured using a laser particle size analyser. The results showed that the flushing treatments had a significant effect on the anti-clogging performance of the emitter and extended the emitter's service life by 35.2% on average. Among the three factors, the flushing pressure lengthened the emitter's service life most. With more irrigation events, the discharged particle sizes V10, V50, and V90 (i.e. the particle size with accumulating particle volumes of 10%, 50% and 90%, respectively) decreased under different flushing treatments. However, particle sizes were still larger than those without the flushing. Particles of all sizes could be trapped in the emitter channel. However, coarse particles were trapped more easily, which was the major reason for emitter clogging. Flushing treatments helped the discharge of sediments. The analysis of variance indicated that the flushing pressure had a significant effect on the discharge of coarse particles and flushing time had an obvious impact on fine particles. Elevating the flushing pressure was the major method to extend the life of emitters for water with large particles >18.04 μm diameter and extending the flushing time was the main way for water with particles <1.20 μm diameter.