| 摘要 |
A pipe thawing apparatus has a heat exchanger for heating water. An electric water pump has an outlet coupled to an inlet of the heat exchanger. A flexible feed tube is coupled to an outlet of the heat exchanger. The electric water pump has an electric motor that is coupled to a source of electric power through a cyclical power interrupting device. The cyclical power interrupting device cyclically connects and disconnects the electric motor of the pump to the source of electric power cyclically turning the electric motor on and off. The water pump thus supplies a pulsating stream of water to the heat exchanger which in turn feeds a pulsating stream of heated water into the flexible feed tube. The flexible feed tube is advanced in the pipe to be thawed so that a pulsating stream of heated water is directed into the pipe, preferably against the ice to be melted. A return line is coupled between the pipe and an inlet of the water pump so that the water used by the apparatus is continuously recirculated. The flexible feed tube has a tip having a spider extending radially therefrom to center the flexible feed tube in the pipe and to facilitate the advancing of the flexible feed tube through the pipe. The spider comprises a plurality of resilient fingers, preferably four, which extend radially outwardly and backwardly from the tip.
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