| 摘要 |
PURPOSE:To provide a gate valve comprising O-rings disposed on the periphery of a pair of opening portions of circulation tubes to a valve box, a pair of valve plates pressed to the O-rings, and a taper member capable of advancing and retreating to be inserted between the paired valve plates, which can reliably block up the tube. CONSTITUTION:A pair of circulation tubes 1, 1' are opened to a valve boc 4, and O-rings 8, 8' are mounted on peripheral grooves 7, 7' disposed on each periphery of the openings. Blocking plates 17, 17' are always urged and retained in such a manner as to approach each other by a reduced original-restoring mechanism 19, and a frame hole 16 mounted on a taper member 13 is fitted to a pin 15 extended between the upper portions of the plates. The bottom of the valve box is provided with a taper projecting 9. As shown in the drawing, an operating rod 12 is pushed in to cause the taper member 13 to outstretch the blocking plates 17, 17', so that the plates are pushed against the O-rings 8, 8' to block up a flow path. When the operating rod 12 is pulled up, the blocking plates 17, 17' are separated from the O-rings 8, 8' to open the flow path by the reduced original-restoring mechanism 19. |
