The present invention relates to a flushing precipitator for separating, by using water injection, foreign substances from gas including foreign substances such as smoke discharged from a coffee bean roasting device, more specifically, to a flushing precipitator wherein an upper nozzle and a lateral nozzle for injecting water inside the body of a precipitator face each other and inject water in the upper and lower directions to efficiently collect dust in the corner of the body and prevent blockage of an upper water supply line and a lateral water supply line, an inflow part for introducing the gas inside the body of the precipitator is connected to the body to be downwardly slanted, an additional auxiliary water supply line is connected to the inflow part so as to enable water to flow along the inside of the downwardly slanted inflow part thereby preventing a back flow of water through the inflow part or preventing the attachment of the foreign substances on the inside of the inflow part, an additional exhaust nozzle is formed inside an exhaust part and reinjects the water into the gas discharged finally through the exhaust part inside the exhaust part so as to increase the dust collection efficiency and prevent the attachment of the foreign substances on the inside of the exhaust part, and the foreign substances are removed from the water including the collected foreign substances discharged from the precipitator through a water reprocessing unit so that the foreign substances-removed water is reused as the water to be used by an injection unit.La présente invention porte sur un dépoussiéreur à aspersion qui permet de séparer, par injection deau, des substances étrangères dun gaz contenant des substances étrangères telles que la fumée dégagée par un dispositif de torréfaction de café et, plus précisément, sur un dépoussiéreur à aspersion, une buse supérieure et une buse latérale, servant à injecter de leau à lintérieur du corps dun dépoussiéreur, se faisant face e
