ES358519A1 - Improvements in or relating to a Grout Injection Lance - Google Patents

Abstract

An appliance for injecting hot grout into a duct comprises an inner tube and an outer tube arranged around and spaced from the inner tube, at least a section of the inner tube extending from the outer thereof being electrically conductive, at least a section of the outer tube adjacent the conductive section of the inner tube being electrically conductive, end portions of said sections being electrically interconnected, and the other end portions of said sections being provided with means enabling said other end portions to be electrically connected to a source of electric current. An inner tube 1 is made from lengths of mild steel pipe, inch O.D. and 1/20th inch thick, brazed into interconnecting sleeves 10, and an outer tube 2 is made from lengths of mild steel tube, 1 inch O.D. and 1/20th inch thick, interconnected as at 11 by swaging and welding. The tubes, which may extend up to and beyond 80 feet, are separated by insulation in the form of a helically-wound asbestos cord 4. At the inlet end the tubes are separated by an insulating collar 6, and at the outlet end are separated by an electrically conducting collar 7. Electric current may be passed through the tubes by respective conductors 8 and 9 secured to the tubes adjacent the inlet end. In use, the appliance is inserted into a duct, electricity is passed through the tubes until the latter reach the required temperature, and hot grout such as bitumen is passed down the inner tube where it is heated by contact therewith, and then rises in the duct around the outer tube where it is also heated by contact therewith. The outer tube may be used as a support for reinforcing elements.