| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of removing valve cover of gate valve which facilitates removal operation of valve cover provided with a valve body and a valve rod in non-cutoff water state while reducing a construction cost and, further, reliably preventing water leakage from a bolt insertion hole of a valve box.SOLUTION: A method of removing a valve cover 4 of a gate valve includes: a process of attaching an annular attachment frame A which surrounds a part of the valve cover 4 to a first connection part 2D of the valve box 2; a process of pushing and fastening a second connection part 4A of the valve cover 4 to the first connection part 2D of the valve box 2 by means of a pushing means B; a process of removing bolt and nut which fastens and connects both connection parts 2D, 4A; a process of performing cutoff of a bolt insertion hole of the first connection part 2D in the pressing state from the lower surface side by means of a pushing cutoff means C equipped on a reactive force receiving part D of the valve box 2; a process of attaching an operation housing H provided with an operating opening and closing valve V2 and an elevation conveying means E to an annular attachment frame A; a process of releasing pushing fastening of the pushing means B, taking out the valve cover 4 into the operation housing H by means of the elevation conveying means E and performing valve-closing operation of the operating opening and closing valve V2; and a process of removing the valve cover 4 in the operation housing H. |
