Comparative Study On Anti-clogging Performance Of Ceramic And Labyrinth Channel Emitter

Ceramic emitter because of energy saving,environmental protection,intelligence and other advantages over traditional maze drip irrigation irrigation,has been rapidly developed in agricultural water-saving irrigation in recent years.Emitter blockage is a long problem of microirrigation technology,difficult to cure the problem.Due to the different working methods of ceramic emitter and labyrinth channel emitters,the previous conclusions on the blockage mechanism of labyrinth channel emitters cannot be directly used in ceramic emitter.Therefore,exploring the clogging mechanism of ceramic emitter under various irrigation conditions can provide some theoretical basis for the development of ceramic emitter.Meanwhile,exploring the difference of anti-clogging performance between ceramic emitters and labyrinth channel emitters is of great significance for the development of ceramic irrigation.To this end,this study selected saline water（salinity:3g/L）,fertilizer water（water-soluble fertilizer,mass concentration:3%）and saline water with fertilizer（salinity:3g/L and water-soluble fertilizer,mass concentration:3%）three different water quality treatment,and the ceramic emitters and 6 types of labyrinth channel emitters were selected for experiment,monitor the change rule of discharge ratio variation（Dra）under different water quality irrigation conditions.Using X-ray diffractometer（XRD）test the clogging substance,and use the scanning electron microscopy（SEM）observation the clogging substance surface morphology and growth process.The difference of anti-clogging performance and causes of ceramic emitter and labyrinth channel emitters under irrigation are discussed,and the blockage mechanism of three kinds of water irrigation is explored.The main conclusions are as follows:（1）The anti-clogging performance of ceramic emitter under saline water irrigation is obviously better than that of labyrinth channel emitters.The irrigation mainly produces chemical blockage under saline water irrigation.The main substance causing the irrigation blockage is Ca CO₃produced by the chemical reaction of ions in saline water.The clogging part of the ceramic emitter was the inner wall rather than the pores.The clogging part of the labyrinth channel emitters were deposited on the tiny runner.The blockage gradually reunite from loose crystals into larger particles.So,it cannot completely cover the microhole in the inner wall of the ceramic emitter,but it can quickly reduce the cross section area of the labyrinth channel emitters,resulting in a rapid decrease of the labyrinth channel emitters flow rate,and the ceramic emitter shows good anti-blockage performance.（2）Under fertilizer water irrigation,the ceramic emitter drops rapidly when the temperature and humidity are high,and shows poor clogging resistance performance on the whole.The blockage under fertilizer water irrigation is mainly（NH₄）₂SO₄.This is because the proteins secreted by microorganisms separated out in a highly saturated ammonium sulfate solution,and（NH₄）₂SO₄is wrapped in the protein.The blockage type is mainly a physical blockage,which may be accompanied by a biological blockage.The ceramic emitter flows out from the inner wall,and because the microhole is very small,the precipitated protein flocculent can not be discharged,and the deposited inner wall forms a dense layer of membrane on the inner wall,completely clogging the microhole on the inner wall of the ceramic emitter,resulting in serious blockage of the ceramic emitter.The protein suspended in the labyrinth channel emitters is discharged with the water flow,and only a thin layer of membrane is attached to the runner wall,which has less impact on the area of the cross section area.In addition,ptfe tape was found to clogging the water inlet in the labyrinth channel emitters.（3）At the end of the test,the ceramic emitter under saline water with fertilizer irrigation was most seriously blocked and showed poor anti-clogging performance.The blockage is mainly（NH₄）₂SO₄.Similar to the blockage mechanism of fertilizer water irrigation,mainly physical blockage,which may be accompanied by biological blockage.The blockage process was also similar to fertilizer water irrigation.The dense membrane forms on the inner wall of the ceramic emitter,while the blockage of the labyrinth channel emitters are thin attached to the runner wall.The fertilizer added to this test contains a large amount of EDTA chelator,which combines with calcium and magnesium ions to form a chelation state soluble in water,which can effectively reduce the generation of chemical precipitation.