Intermediate frequency heating pipe plastic liner device

[0009] In the following, the present invention will be further described with embodiments in conjunction with the accompanying drawings.

[0010] A pair of self-locking sealing plugs 13, 18 are made of steel. One end of the plug 13 is in the shape of a flat-top bottle stopper. The outer diameter of the stopper body is slightly smaller than the inner diameter of the lined plastic pipe 12. The diameter of the flat cover of the stopper body is equal to the outer diameter of the steel pipe 11, and an axial through hole 21 is opened in the stopper body. The outer port of the axial through hole 21 is equipped with a self-closing quick connector 8 for inflation, and a pull ring 14 is provided on the inner end of the plug; the other end plug 18 is a straight plunger with a diameter slightly smaller than the inner diameter of the lined plastic pipe, outside the straight plunger The end is provided with a ring groove that matches with the semicircular snap ring 19. A pull ring 20 is provided on the outer end of the straight plunger, and a tension spring connecting rod 17 made of steel is provided in the center of the inner end surface. One end of the tension spring 16 is opposite to the connecting rod 17. The other end is connected with a hook connecting rod 15 with a hook at the front end. The sealing ring 10 is installed in a ring groove opened where the plug bodies of the plugs 13 and 18 and the two exposed sections of the lined plastic pipe 12 are mated. The processed steel pipe 2 is composed of a steel pipe 11 and a plastic lined pipe 12 inserted close to the inner wall of the steel pipe 11. The plastic lined pipe is slightly longer than the steel pipe 11 and is on the pipe section of the lined plastic pipe 12 that extends outside the two ends of the steel pipe 11 Put on the anti-induction copper sleeve 9. As attached figure 2 When starting processing, first insert the plug 18 that connects the connecting rod 17, the tension spring 16, and the hook connecting rod 15 from right to left into the lined plastic pipe of the processed steel pipe 2 until the hook hook at the front end of the hook connecting rod 15 Hold the pull ring 14 on the inner end surface of the plug 13 and use a tool to hook the pull ring 20 on the outer end surface of the plug 18 and pull it outward. Insert a semicircular snap ring 19 inside, so the plugs 13, 18 are connected to the tension spring 16 to block the two ports of the processed steel pipe 2. The sealing ring 10 on the plugs 13, 18 is just in the anti-induction copper sleeve In the two exposed sections of the lined plastic pipe 12 with a lower temperature below 9; at this time, the compressed air is filled into the lined plastic pipe from the air source 1 through the self-closing quick connector 8 for inflation on the plug 13 at the inflation pressure of 0.2~ 0.4MPa; the inflated steel pipe to be processed is placed on a single-track roller table consisting of a number of V-groove rollers 6 and its transmission shaft 5, and transmission chain 4, and passes through the intermediate frequency induction heating coil placed in the middle of the track at an appropriate speed 3. Complete the heating process; then cool by the spray device 7 on the roller table; remove the compressed air in the pipe by squeezing the pressure relief thimble of the self-closing quick connector 8 for inflation; remove the plugs 13, 18 and anti-aircraft pipes at both ends of the processed steel pipe Induction copper sleeve 9; Finally, cut off the plastic pipe section whose inner plastic pipe 12 is longer than the steel pipe part to obtain the plastic-lined composite steel pipe product.