To interpose a low-priced projecting elastic body for automatically controlling slide of an inner and an outer tubes in a clearance between the inner and the outer tubes of a fire-proof straight double tube.
The fire-proof straight double tube 1 is formed by covering the inner tube 2 made of a synthetic resin such as hard vinyl chloride with the outer tube 3 made of fiber-mixed mortar, and interposing the projecting elastic body 5 in the clearance 4 between the inner tube and the outer tube, while compressing with wall surfaces of the inner and the outer tubes, to control relative slide of the inner and the outer tubes to each other. The projecting elastic body 5 is formed by coating a peripheral surface area of the inner tube to be covered with the outer tube with hot-melt adhesive 6 at a height more than an interval of the clearance.
JPS49817A | 1974-01-07 | |||
JP2003166673A | 2003-06-13 | |||
JP2000291841A | 2000-10-20 |