A boring device for a lining material in a branched portion of a lined pipe such as a gas-conduit or a city water pipe line to which the lining material has been applied, which device includes a tension coil spring 1, a compression coil spring 2 being connected to the tip of the tension coil spring and having a spring constant smaller than that of the tension coil spring, a head element 5 in the form of a circular truncated cone being connected to the tip of the compression coil spring 2 and having an electric heat-generating device 3 coated with a thermoplastic resin and a single or plural transmission wires 9 being connected to the heat-generating device 3 and being passed in a loosened state through the tension coil spring 1 and the compression coil spring 2, the transmission wires 9 being fixed within the tension coil spring 1 at plural points, and a device N provided in rear of the tension coil spring for rotatably extending the device.

A electric heating apparatus for de-icing pipes includes a flexible hose with a closed bottom end and a top end. The hose has a pair of insulated wires situated within an interior of the hose and a plug coupled to the top end of the hose. The plug has a pair of contacts connected to the wires and adapted to be inserted within a conventional electrical receptacle for providing electrical power to the wires. By this structure, the hose is adapted to be passed within a pipe connected to a source of water. Next provided is a thermostat having an input connected to the insulated wires and is adapted to allow the transfer of power to an output thereof upon the detection of a temperature below a predetermined degree. The thermostat is situated within the interior of the hose adjacent the bottom end thereof. Also included is a heating coil formed within the hose, wherein the coil is connected to the output of the thermostat for radiating heat upon the receipt of power. Finally, a lead weight is coupled to the hose at the bottom end thereof for facilitating the passing of the hose through the pipe.

A process to clear pipelines carrying fluids viscous and/or rich in organic residues includes the introduction of a heating element inside a pipeline carrying the fluids through a coupling spool which is intercalated in the fluid-carrying pipeline. Simultaneously an electric current is applied to the heating element so that the heat generated by the heating element is transmitted to the viscous fluid or to the compacted residual mass inside the fluid-carrying pipeline, causing the detachment of those residues from the internal wall of the pipeline and re-establishing the conditions for fluid flow.

A longitudinally flexible electrical heating element for a dryer is provided which permits the heating element to be inserted into and removed from a vertical air inlet conduit located behind the dryer drum from the front of the dryer. A front panel of the dryer is removed and the heating element is inserted or removed through an inlet aperture in the air inlet conduit which opens into the interior of the cabinet.

A device for boring tunnels to accommodate electrical cables or conduits in the thickness of an insulative material of a composite wall panel exhibiting a layer of this material covered on one or both sides with a rigid facing sheet made up of a mobile system and a positioning and guiding device for the mobile system. The mobile system incorporates a boring member mounted at the end of a flexible member, and the positioning and guiding device incorporates a removable support featuring means for attaching it to the or one facing sheet, in line with an opening formed in the latter, and a bent guide conduit adapted to be inserted into this opening. This conduit enables the boring and flexible members to penetrate into the insulative material parallel to the facing sheet, in the required direction and to the required distance.