DEVICE FOR THE REPEATED INJECTION OF GROUT MATERIAL IN LIQUID STATE INTO A VOLUME TO BE TREATED

摘要

A device for the repeated injection of liquids into a volume to be treated comprises piping in which is provided a valving construction that opens to the volume to be treated only when the pressure of the liquid in the piping exceeds a given value. In one embodiment the valving construction comprises a perforated tubular body surrounded by a sleeve of resiliently flexible material.