SELF-HEATING TYPE HEAT-CONTRACTIVE TUBE

摘要

PROBLEM TO BE SOLVED: To prevent corrosion of a body to be protected and to cover it by providing a heater in the inside of a heat-contractive tube and making the heater in a mesh or a bamboo blind shape. SOLUTION: A heat-contractive tube 1 is constituted by making thermoplastic resin of a polyethylene tube or a crosslinked polyethylene tube in a pipe shape. Thermoplastic resin and its crosslinked resin are used for the heat-contractive tube 1. A heater 3 is to be a heating wire consisting of aluminium rod. The heater 3 is made of metal having an electric potential which is base rather than steel of a body to be protected, in a mesh type and both end parts are end part electrodes 3a. A heating value required for the heat-contractive tube 1 is supplied in accordance with thermal condition of the thermocontractive tube. A pressure sensitive adhesive layer 2 is formed on an inner surface of the heat-contractive tube 1. A plant covered part (b) of a covered steel tube (p) in the neighbourhood of a tube coupling part is peeled, and after welding an end part, a steel tube exposed surface and a welded bead part (a) between the plant covered part (b) are covered by the heat-contractive tube 1. The thermocontractive tube is contracted and closely applied on the body to be protected by carrying a current from the end part electrode 3a.