| 摘要 |
<p>A shutoff valve includes a positive position indicator for indicating the position of a piston in the valve. The valve position indicator is operably connected to a piston within the valve so that movement of the piston causes a corresponding movement of the valve position indicator. The shutoff valve may also include one or more springs acting on the piston to close the valve. Each spring is independently capable of closing the valve.</p> |
