| 摘要 |
A manually operable pressure relief valve for swimming pool filter systems and the like, including a valve housing, a valve stem movable axially in the housing to open and close the valve, and a top cover that serves as an operating handle. The valve housing and the valve stem have components that cooperate to provide an axial movement from closed to fully open with only a quarter turn of the stem, and to prevent inadvertent removal of the stem from the housing. The stem must be moved deliberately through a sequence of required rotational and axial displacements to remove it. The top cover must also be manipulated in a prescribed manner to effect removal of the stem from the housing. |
