| 摘要 |
A linear actuator monitors and distinguishes between the open and closed states of a valve. The states of the actuator are monitored electrically by two switches and visually via a mechanical indicator. The electrical switches are initialized by an adjustable system, according to the random position of the valve stem when it is opened or closed. The visual indicator is also adjusted to an initial position corresponding to the valve stem position. The adjustment of the system allows for flexibility and use on a wide range of valve stems with various stroke lengths. The visual indicator is visible from the top and the sides of the unit. It is visible on the circumference of the unit so that it is visible at an angle as well. The visual indicator matches three possible states of the valve as follows: when the valve is closed, the indicator is not visible, when the valve is either opening or closing, only one indication area is visible, and when the valve is fully open, two indication areas are visible.
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