METHOD AND DEVICE FOR BENDING MATERIAL TUBE

摘要

A material tube (30) is bent at plural positions in its intermediate portion with both ends of the tube (30) tightly sealed with sealers (31, 32) and liquid filled in the tube (30). Pressure in the material tube (30) can be increased and reduced through the sealers. The pressure in the tube (30) is adjusted bending by bending for the plural bending processes. After one bending process is finished, the pressure in the tube (30), which pressure is adjusted to a pressure suitable for the one bending process, is adjusted from the pressure to a pressure suitable for the next bending. This reduces man-hour to increase work efficiency.