PURPOSE: To manufacture a bimetallic curved tube in which an external tube is attached tightly to the external surface of an internal tube by giving internal pressure to the bimetallic curved tube to deform it in a radial and external direction and heating and cooling the circumference of the external tube continuously and annularly in its lengthwise direction.
CONSTITUTION: An unattached bimetallic curved tube 1 composed of the external tube 11 and the internal tube 12 is set to a rotary frame 2 to fix a connector 7 and a blind patch 8 to both its ends. A hydraulic device 6 is connected with the connector 7 to fill the internal part of the curved tube 1 with pressure water, plastically deforming pressure is added to the internal tube 12 and the tube is stably and plastically deformed in the radial and outward direction to be pressed against the internal surface of the external tube 11. Simultaneously, one end of a zone to receive diameter- reducing treatment is begun to be heated by a thermally equalizing coil 4, is heated up to a desired temperature, and as so as spray cooling is started, a rotary frame 2 is revolved in an A-direction, the curved tube 1 is moved to the thermally equalizing coil 4 to make a continuous annular heating and cooling. In this way, the external tube 11 is thermally shrunk and attached tightly to the external surface of the internal tube.
Sousai, Shiyouji
Tanaka, Takashi
Murakami, Yasuo
Suzuki, Masayoshi
Suzuki, Masao
DAI ICHI HIGH FREQUENCY CO LTD