Apparatus for dewatering boreholes

Claim 1

Apparatus for ejecting water from flooding blasting boreholes and the like, which includes an inflatable bore-hole plugging packer body having an upper head, a lower head, and an elastic expansible peripheral wall secured in gas tight relationship to both heads, and having through said upper head an inflating and water-ejecting gas supply line of predetermined gas flow-rate capacity and a rigid water discharge pipe passing through both heads, said apparatus comprising in combination the following improvements: a. means fixed securing both heads to said rigid discharge pipe so as to prevent relative movement between said heads when said packer body is inflated, b. a predetermined and selectively sized open orifice for restricting gas flow in said lower head, designed to permit continuous gas flow at a rate so controlled that a build-up of pressure will occur in said body as inflating and water-ejecting gas is supplied thereto through said gas supply line sufficient to insure holding of the body by frictional contact with a borehole wall against developing pressure below while permitting a gradual build-up of said developing pressure below to force the water in the borehole into said discharge pipe, said orifice also permitting said gas to flow through said lower head after the borehole water has been forced into the discharge pipe so as to blow water in said pipe completely out of said pipe, and c. a substantially water-impervious borehole liner or membrane secured to said discharge pipe and lining the borehole walls below the packer body so as to substantially inhibit water in the borehole from flowing back into the formation of said borehole walls because of water-ejecting pressure in the borehole.