| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pressure release lid for a drainage line, capable of surely releasing a pressure even when the rise of a pressure inside the drainage line is relatively small, restoring an original state even when sand or soil or the like intrudes when releasing the pressure, and preventing infiltration of rainwater. <P>SOLUTION: The pressure release lid for a drainage line includes: a lid body 4 fitted inside a lid frame and provided with a through-hole 5 passing through in the vertical direction; a movable opening/closing lid 6 movable in the vertical direction between a lower limit position at which it closes the through-hole 5 and an upper limit position at which it floats from the lid body 4 and opens the through-hole 5; a guide part 7 for regulating the moving direction in the vertical direction; and annular packing 8 mounted on an outer peripheral surface of the movable opening/closing lid 6 to block infiltration of rainwater to the through-hole 5. Particularly, an inner peripheral surface of the through-hole 5 has a tapered inclined inner peripheral surface 17 for reducing an opening area more on the lower side, the movable opening/closing lid 6 is provided with an inclined outer peripheral surface 19 matched with the inclined inner peripheral surface 17, and the packing 8 is disposed at a position to be in press contact with the inclined inner peripheral surface 17 of the through-hole 5. <P>COPYRIGHT: (C)2012,JPO&INPIT |
