A device includes a container for storing slurry, a main pipeline with one end connected to the container and the other end extending to an inner space of the container and forming a first circulation path, a nozzle attached to the other end of the main pipeline, a pump provided in the first circulation path between one end and the other end of the main pipeline for sucking and pressurizing slurry, a sub-pipeline which branches from the pump or branches from the main pipeline between the pump and the nozzle and extends to the inner space of the container and forms a second circulation path, a valve for switching distribution of slurry to one or both of the first and second circulation paths, and a discharge port provided at a tip opposite to a branch end of the sub-pipeline and located below the nozzle in a vertical direction.