| 摘要 |
A relief valve for extracting sub-surface gas from beneath a geomembrane includes a valve body for permitting gas to flow therethrough and includes an inlet, an outlet, a vertical run communicating with the inlet, and a lateral run communicating with the vertical run and the outlet. A ball valve comprising a ball seat is positioned within the vertical run. A lightweight valve ball positioned within the vertical run. The valve ball is movable therewithin between a lowered position against a ball seat and an elevated position distal therefrom. The valve ball is lightweight enough that minimal upward gas flows within the vertical run cause the valve ball to rise and become unseated from the ball seat such that stoppage of such vertical flows or reverse flows cause the valve ball to drop back to its ball seat and seal against reverse flows through the ball valve. |
