Patent ID: 7799214

Claim:
A device for removing a precipitate present in a surface treatment liquid comprising: a surface treatment tank in which the surface of an article is treated by the surface treatment liquid; a pool tank connected to a pressure reduction mechanism and communicated with the surface treatment tank through a communication control valve, wherein after the pressure reduction mechanism reduces the pressure within the pool tank to a predetermined level of the reduced pressure while the communication control valve is closed to obstruct communication with the surface treatment tank, the communication control valve is opened to allow the pool tank to use a negative pressure to recover and contain the contaminated surface treatment liquid that has treated the surface of the article in the surface treatment tank; and a precipitation tank in communication with a lower end of the pool tank through a communication pipe arranged with a switch valve, wherein the precipitate in the pool tank, after said precipitate in said pool tank subsides, is introduced into the precipitation tank, wherein the pool tank and the surface treatment tank are connected by a return tube for conveying the surface treatment liquid from the pool tank to the surface treatment tank and by a conveying tube for conveying the surface treatment liquid from the surface treatment tank to the pool tank, the tubes arranged in parallel between the communication pipe and the surface treatment tank.