Tunnelling unit with air-pressurised digger and discharge spaces - has connecting conveyor sealed from accessible atmosphere operator space

摘要

The unit for digging a 1-3 m diameter tunnel comprises a tube containing a space with a digger at its forward end. The space is air-pressurised to prevent entry of sub-soil water. - This space is hermetically sealed from a space for the operator by a bulkhead which space is, in turn, similarly sealed from a space where the dug material is discharged by a conveyor belt extending through the operator space inside a hermetic duct. The operator space connects to an entry/exit space at the rear of the unit via a sealed passage.