| 摘要 |
PURPOSE:To give necessary energy density irrespective of the resistance value of an electric heating wire and condition establishment in relation to the electric heating wire necessary for that can be performed easily, by a method wherein an established voltage is given in accordance with a kind and bore of a joint. CONSTITUTION:At the time of connection of plastic pipes, a voltage is established in accordance with a kind and bore of joint in a fusing method of an electrofusion joint which is obtained by laying an electric heating wire into a contacting surface with the pipe. That is, when the electric heating wire of the same wire is used for a socket joint and cap joint and designed at the same pitch, the total resistance of the electric heating wire of the cap joint is halved and since the voltage is halved, generation of half of the total energy of that of the socket joint becomes possible. Therefore, the electric heating wire of the same wire is used for a matter whose fusion area is 1.5 times as much as that of the socket joint and designed at the same pitch in the socket joint, the total resistance of the electric heating wire becomes 1.5 times and giving voltage becomes 1.5 times. Since the voltage is changed even if intrinsic resistance of the electric heating wire is not changed, output energy is changed and necessary energy density is obtained. |
