| Physical plugging is the most common forms of emitter clogging and representedby sediment, without considering the impact of changes in the external environment andanti-clogging performance is mainly influenced by the characteristics of sediment particles,especially in sediment particle size and concentration. So in order to investigate the influenceof sediment particle size and sediment concentration on the clogging processes of labyrinthchannels emitters, periodic intermittent drip irrigation experiments were carried out usingmuddy water containing particles with6different particle ranges (all less than0.1mm) whichwere screened by means of sieving method, each particle size range of sediment areformulated to0.5,1.0,1.5g/L of muddy water to analysis the influence on emitter clogging indifferent particle size and sediment concentration, find the sediment particle size range andcritical sediment concentration levels which are easily cause emitter clogging. When the testfinished then collect the sediment which depositing in the labyrinth channel, at least thelocations of sediment clogging were observed using electron microscopy and take picture tocompare the difference between the status quo sediment and the clogging sediment to provenmechanisms that cause clogging of sediment particle size in different range. Finallycombining with the single particle size test results to select four different sediment gradationfor muddy clogging test. It also analysis the location of alluvial sediment and sizecomposition, sediment concentration and flow changes. In this paper we find the followingconclusions:1) The results show that, the sensitive sediment particle range that cause easyclogging is depending on the sediment concentration. When the sediment concentration is lessthan1.3g/L, the most easily cause clogging particle ranges are between0.075-0.1mm and0.03-0.038mm and after a certain number of irrigation blocking development quickly;particle ranges from0.05-0.075mm and0.02-0.03mm are lesser; while the ranges that mostdifficult to cause clogging are0.038-0.05mm and less than0.02mm. Therefore, in the courseof the actual irrigation filtration reasonable measures should be selected to filter the sediment which range are in0.075-0.1mm and0.03-0.038mm to reducing the chance of emitterclogging.2) When the sediment concentration is less than1.3g/L, particle size is consideredas the main cause of clogging, the effect of sediment particle size on clogging is weaker;When the sediment concentration is greater than the critical value that between1.2-1.3g/L,the effect of sediment particle size on clogging is weaker and sediment concentration becomesthe main factor to cause clogging. So the irrigation water should be standing and precipitationas much as possible to keep the sediment concentration are less1.3g/L.3) In this test the location which the sediment easily to cause clogging are inlet andthe tooth runner and the probability of clogging in other locations is small. The sedimentwhich is caused clogging were observed using electron microscopy and take picture tocompare the difference between the status quo sediment, The results also appeal that when thesediment particle size range is between0.038~0.1mm the reason to cause clogging aresubsidence and accumulation;Sediments can easily condense into aggregates to get drippersclogged when the sediment particle size range is less than0.038mm. So in the actualirrigation we should be added to the appropriate amount of dispersing agent to inhibiting theformation of aggregates of sediment.4) When the sediment concentration is less than1.0g/L, the concentration whichparticle size range of0.03-0.05mm and0.05mm have much proportion are the most easily tocause clogging; When the sediment concentration is greater than1.0g/L,the influence ofsediment proportion to clogging is reduced and sediment concentration becomes the mainfactor to cause clogging.5) Though analysis the location of alluvial sediment and size composition, sedimentconcentration and flow changes Large amount of sediment deposition appeared in theemitting-pip which are clogging, mainly in the place of0.6-1.0m，there have small amount ofsediment in the emitter-pip which are not clogging, and the place of sediment deposition arerelatively later. The sediment particle size between0.05-0.1mm are easily deposited in theemitter-pips, but when the sediment size are less than0.03mm,it can discharged from theemitters. So when the irrigation water have much sediment we should try to filter out largerparticle size of sediment to reduce the probability of emitter clogging. In connection with thesediment which in the drip, the pip should be washed to extend the life of dropper system.Sowhen high sediment concentration in irrigation water, should try to filter out particles largerparticle size, reducing the probability of emitter clogging. The sediment in the drip irrigation,it should be combined with the actual situation, time to drip irrigation to wash, to extend the life dropper system... |
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