| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology related to a cylindrical protective member for covering outside of a polyethylene pipe for gas, in particular the cylindrical protective member of which installation work is easily carried out by folding back a sheet at its center in a width direction and keeping its both ends in the width direction in double-folded state, arranging fixed parts and non-fixed parts alternatively at both ends to form a cylinder shape there.SOLUTION: A cylindrical protective member covers an outside part of a polyethylene pipe of prescribed length for gas that is buried in the ground. The cylindrical protective member 1 is manufactured by a process in which a sheet 2 having substantially the same length as that of polyethylene material for gas and having a width larger than an outer peripheral length of the polyethylene pipe for gas is folded back at its center 2c in width direction, keeps both ends 21 in its width direction under double-folded state, and fixed parts 22 and non-fixed parts 23 are alternatively arranged at both end parts 21 to form a cylindrical shape. The sheet 2 is a product in which at least two woven sheets of synthetic resin flat yarn are laminated, a length of the fixed parts 22 is 400 mm to 800 mm, a length of the non-fixed parts 23 is 70 mm to 200 mm and a tear strength of the fixed parts 22 is 20 N to 40 N.SELECTED DRAWING: Figure 1 |
