Lowering groundwater level by digging pit and pumping out water, by sealing pit airtight and creating vacuum inside it using vacuum pump

摘要

The pit (23) is sealed airtight and a vacuum is created inside the pit space using a vacuum pump (27). The pit is at least partly permeable, the permeable portion of the pit being located in the ground. A pump placed inside the pit is used to remove water from it. An independent claim is also included for a system (21) comprising an at least partly permeable pit containing a pump (25) at the bottom, a removable cover (33) for sealing the pit airtight and a vacuum pump (27).