Apparatus for grouting

Claim 1

Apparatus for injecting grouting fluid under pressure comprising: means for pumping grouting fluid from an inlet at low pressure to an outlet at high pressure, nozzle means, conduit means for conducting grouting fluid from said outlet to said nozzle means; said nozzle means including a tapered shank portion having a passage extending from the base end to the distal end, said conduit means communicating with said passage, said shank portion having an external screw thread thereon, said screw having a thread profile defined by the thread crest and an outer thread face and an inner thread face on opposite sides of said crest, said outer thread face being on the distal end side of said crest and having a greater proportion of surface area of said thread profile than said inner face, said outer thread face having a substantially constant taper in the direction of said distal end and having a greater slope than the taper of said shank portion; and a resiliently compressible tube having a central bore smaller than said shank portion at said base end and larger than said shank portion at said distal end, whereby said outer thread face expands said tube to engage the surface of a bore hole in a wall without cutting said tube and thereby resists blowing out due to the pressure of said grouting fluid in said bore hole.