| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of removing a valve cover of a gate valve which facilitates removing operation of the valve cover provided with a valve body and a valve rod in non-cutoff water state with high efficiency while reducing construction cost.SOLUTION: A method of removing a valve cover 4 of a gate valve includes: a process of attaching an annular attachment base material to a valve box 2 in a water-tight state while allowing insertion and removal operation of a lock member; a process of maintaining water-tight state between the valve cover 4 and the valve box 2 by pushing the valve cover 4 against the valve box 2 by means of a pushing means provided on the attachment base material; a process of releasing fastening connection between a connection outer fitting part 2A of the valve box 2 and a connection inner fitting part 4A of the valve cover 4; a process of attaching a working housing H provided with a working opening and closing valve V2 and an elevation conveying means D connected to the valve cover 4 to the attachment base material in water-tight state; and a process of releasing the pushing fastening of the pushing means, taking out the valve cover 4 into the working housing H with the elevation conveying means D and performing valve-closing operation of an operating opening and closing valve V2. |
