초록 ▼

A welding sleeve for connecting pipes formed of thermoplastic material includes an electrical conductor in the form of an electrical resistance wire. The resistance wire extends around the sleeve and has a pair of opposite ends for conveying current through the wire. The opposite ends of the wires c

A welding sleeve for connecting pipes formed of thermoplastic material includes an electrical conductor in the form of an electrical resistance wire. The resistance wire extends around the sleeve and has a pair of opposite ends for conveying current through the wire. The opposite ends of the wires can be connected directly to a source of electrical current, for instance a 220°V＿line. It is not necessary to provide transformers or timing relays. A melting material is incorporated into the conductor between its ends and it melts through when the energy necessary for welding the sleeve has been developed. After the current is supplied through the resistance wire, the welding process is completed when the predetermined melting material melts through. Such sleeves can be manufactured in a mass production operation, and the sleeves are much safer than the conventional devices used to-date.

대표청구항 ▼

A welding sleeve for connecting pipes formed of thermoplastic material comprising an axially extending sleeve member having an inner surface and an outer surface with the inner surface arranged to contact the pipes to be connected, an electrical conductor is located in said sleeve member in the form

A welding sleeve for connecting pipes formed of thermoplastic material comprising an axially extending sleeve member having an inner surface and an outer surface with the inner surface arranged to contact the pipes to be connected, an electrical conductor is located in said sleeve member in the form of a resistance heating wire having a pair of opposite ends, said opposite ends arranged for conveying current through said heating wire, said resistance heating wire is arranged in said sleeve member for heating the inner surface of said sleeve for transmitting the heat to the pipes to be connected, characterized in that said resistance heating wire includes a predetermined melting material located between the opposite ends of said resistance heating wire so that said material melts through approximately when the heat energy required for welding said sleeve to the pipes to be connected has been developed and causes the termination of the flow of current through said electrical conductor and thereby the discontinuance of heating said sleeve by said resistance heating wire.