Earth discharging device for upward-facing shield machine

摘要

An earth discharging device, for a shield machine for constructing a tunnel in the vertical direction, has a pipe for discharging downwardly earth and sand that have been excavated by the machine as it advances upwardly. An elastic film-type valve is provided in the earth discharging pipe, which valve expands and contracts diametrically by means of fluid pressure to open and close the interior of the earth discharging pipe. A gate mechanism follows the elastic valve and adjusts the sectional area of the space through which earth and sand pass inside of the earth discharging pipe. The gate mechanism narrows the sectional area of the earth discharging pipe at the outlet side of the elastic valve so as to create a substantially uniform earth pressure upon the entire elastic valve to inhibit blockages and eruptions that might otherwise occur.