| 摘要 |
<p>PURPOSE:To increase the adhesion of sheathing concrete and reduce cost by simple constitution by casting and forming a plurality of stepped sections to the outer circumferential surface of a faucet so that each stepped surface is shaped along the tubular radial direction and covering the stepped sections with sheathing concrete. CONSTITUTION:A groove section 15 is formed to the inner circumferential surface of the faucet 14 of a cast iron tube 12 and the inner circumferential surface is formed in a stepped shape, and a plurality of stepped sections 17 corresponding to the form of the inner circumferential surface are shaped to an outer circumferential surface through casting. The stepped surfaces 18 of each stepped section 17 are formed along the tubular radial direction while a rubber ring 16 is disposed to the groove section 15. The outer circumference of the drum section of the cast iron tube 12 is covered with sheathing concrete 13 into which vinylon fibers 21 are mixed, thus constituting a propulsive tube 11(19). Adhesion to the cast iron tube 12 of sheathing concrete 13 is increased by the stepped surfaces 18, the damage of sheathing concrete 13 is prevented, the labor hours of the formation of the stepped sections 17 are omitted, and cost is reduced by the stepped sections 17.</p> |
