| 摘要 |
PURPOSE:To prevent exfoliation between a lining material and backing elastic material, by providing annular grooves externally of the good moisture-permeability backing elastic material, while providing water relief holes in a main unit and discharging water, in high temperature corrosive gas of high concentration, to the outside of the main unit. CONSTITUTION:A lining material 3 and good moisture-permeability backing elastic material 4 are provided from fluorine resin and the like in the internal surface of a main unit A. An annular groove 4b is provided in an external surface of the elastic material 4 and around an opening fitted to a valve shaft 6 in an external surface of the main unit A, further annular parallel grooves 4a, communicated to this groove 4b, are provided, while water relief holes 1a, 2a, radially extended through, are provided to be communicated to the before said grooves in the main unit A. In this way, accumulated water, between the elastic material 4 and the main unit A, permeably through the lining material 3 and the elastic material 4 from the inside of a valve, can be discharged, and deformation of the elastic material 4 is prevented, thus a life of the valve can be extended. |
