Device for removing gravels and the like from discharged mud in

Abstract

A device for removing relatively larger size gravels, stones, crushed rocks and the like contained in a discharged mixture of fed slurry or muddy water and excavated ground formation components in hydraulic tunnel boring systems. The device comprises a lattice-shaped classifying means connected at one end to a discharging pipe for conducting the mixture from the tunnel face, a primary chamber connected to the other end of the classifying means for receiving and storing classified gravels and the like, and a secondary chamber communicating with the primary chamber through a valve for receiving and retaining the gravels and the like filled in the primary chamber. A housing surrounds and rotatably supports the classifying means and includes a discharging pipe for conducting muddy water passed through the clarifying means. A motor rotates the classifying means for performing classifying work. The secondary chamber has a valve on its discharging side and the valve between the primary and secondary chambers and the valve of the secondary chamber are alternately closed and opened so that removal of the classified gravels and the like may be made without interrupting the hydraulic tunnel boring. The device is preferably provided at the discharging position of the secondary chamber for weighing classified and discharged gravels and the like for determining actually excavated amount of the ground formation components in cooperation with means for determining dry mud amount provided in feeding and discharging pipes of the slurry or water and the mixture.