| 摘要 |
PURPOSE: By respectively forming the extension spray lance penetration prevention projection and extension spray lance entry preventing operation projection on the outside main tube part and outside extension pipe part the outside outlet box easily transfers the outside extension pipe part according to the direction growing distant from the inside outlet box. CONSTITUTION: The outside main tube part(10) is at least arranged of the lower surface of the outside main pipe body portion(11) in a pair of region symmetrical according to the longitudinal direction of the outside main pipe body portion as in-line. The outside main tube part comprises the extension spray lance penetration prevention projection(15) having the extension spray lance penetration prevention side and extension spray lance withdrawal guide plate. |
