Physical clogging caused by solid particles are considered as the most common
plugging form of emitter, and also the direct reason that leads to emitter clogging. Under
special emitter channel structure, sediment characteristics and water temperature is a major
factor affecting the anti-clogging performance of emitters. The objective of this study was
to investigate the influence of small sediment particles containing in muddy water on
anti-clogging performance of oblique dental labyrinth channel drip emitters. A total of 8
types of muddy water with different particle size distribution (all less than 0.1 mm) were
tested by short-term clogging tests, and determine the sensitive ranges of particle diameters
and sediment concentrations that cause different clogging levels. According to the relative
discharge of emitters and the deposition sites of sediment particles in the labyrinth channel,
these 8 kinds of particle sizes were classified into 3 clogging levels: difficultly clogged
(DC), easily clogged (EC), and very easily clogged. Afterward, the intermittent drip
irrigation method were adopted to investigate the effects of sediment concentration,
sediment particle size and water temperature on the genesis and processes of labyrinth-path
emitter clogging, and conducted to further prove the results obtained from the short-term
clogging tests Finally. the clogging level of drip irrigation systems was evaluated on the
basis of relative average flow volume (qr) and irrigation uniformity coefficient (Cu) of
emitter flow. The results aim to help in improving drip irrigation methods using water with
high sediment concentration. By the above mentioned analysis and studies, this paper gets
the main results as follows:
First, fine particles caused labyrinth emitter clogging at similar locations as large
particles, which generally occurs at the inlet and corners of the vortex and low velocity of the flow channel. The sediment particles in labyrinth emitter had random characteristics for
the deposition cell and regularity for the sedimentation position.
Second, the inlet pressure is a main factor affecting the clogging level, and the impact
of the inlet pressure on clogging is neither monotonically increased nor decreased.
Sediment concentration and particle sizes are also primary factors affecting emitter
clogging. When the sediment particle sizes are less than 0.1 mm, the less the sediment
particle size, the easier the emitter will be clogged. In addition, the degree of emitter
clogging rises sharply with the increase of sediment concentrations. There is a coupling
relationship between the sediment characteristics and water temperature of muddy water. If
particle diameters ranges between 0.03 mm and 0.1 mm and the sediment concentration
less than 1.25 g/L do not significantly affect the clogging of emitters. When the sediment
particle sizes less than 0.031 mm, the possibility of clogging rapidly increases at sediment
concentrations of 1.25-1.5 g/L.
Third, The degree of emitter clogging was also impacted by water temperature.
Emitters were less likely clogged by muddy water with higher temperature. The
anti-clogging property of emitters improves with increasing water temperature. The reason
is that the possibility of collision, adhesion, cohesion and separation interaction among the
sediment particles will be higher. The finer the sediment particle sizes, the more prominent
are the influences of the water temperature on anti-clogging performance of emitters. It
was found that in the summer when water temperature was relatively high labyrinth-path
emitters were prone to clogging by sediment with particle sizes less than 0.031 mm.
Four and last, it is very difficult to evaluate the clogging level of the drip irrigation
system by only using the relative emitter discharge. The article proposes a emitters
clogging comprehensive evolution method and generalized model on the basis of relative
average flow volume (qr) and irrigation uniformity coefficient (Cu) of emitter flow.
However, owing to the errors of the parametric hypothesis, the generalized model formula
exist big errors, the comprehensive evolution method of emitters clogging needs further
Key Words：Emitter , Clogging , Sediment particle size , Sediment concentration , Water