초록 ▼

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

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.

대표청구항 ▼

1. An apparatus for indicating a state of a valve, the valve having a stem being movable in closing and opening directions between closed and open valve positions, the apparatus comprising: a first cam system being biased in the opening direction, the first cam system capable of adjustably engagin

1. An apparatus for indicating a state of a valve, the valve having a stem being movable in closing and opening directions between closed and open valve positions, the apparatus comprising: a first cam system being biased in the opening direction, the first cam system capable of adjustably engaging the stem when the stem is adjacent to the closed valve position and being movable by the stem in the closing direction once engaged, and a second cam system being integral to or separate from the first cam system and being biased in the closing direction, the second cam system capable of adjustably engaging the stem when the stem is adjacent to the open valve position and being movable by the stem in the opening direction once engaged, and an indicator moveable by the first and the second cam systems and capable of indicating at least open, intermediate, and closed states of the valve. 2. The apparatus of claim 1, wherein each cam system comprises: a holder biased by a spring and capable of moving the indicator, a rod on the holder, and a member being adjustable on the rod. 3. The apparatus of claim 2, wherein the adjustable member is a ring being threaded on the rod and defining a split, the split fitting into a track on the holder.4. The apparatus of claim 2, wherein the stem has an adapter to engage the adjustable member.5. The apparatus of claim 1, wherein the indicator is biased in the closing direction.6. The apparatus of claim 1, wherein the indicator indicates the intermediate state in the absence of engagement of the stem with the first and second cam systems.7. The apparatus of claim 1, wherein the indicator comprises first and second visual portions, the indicator indicating neither portion for the closed valve state, indicating only one portion for the intermediate valve state, and indicating both portions for the open valve state.8. The apparatus of claim 1, wherein the indicator comprises: a first member capable of engaging the first cam system when moved by the first biasing member in the opening direction, and a second member being further disposed in the closing direction than the first member and capable of engaging the second cam system when moved by the stem in the opening direction. 9. The apparatus of claim 1, further comprising a first switch capable of being actuated by the first cam system when the stem is at the closed valve position; and a second switch capable of being actuated by the second cam system when the stem is at the open position. 10. The apparatus of 9, wherein the first and second switches electrically indicate the open, intermediate, and closed states of the valve.11. An apparatus for visually and electronically indicating a state of a valve, the valve having a stem being movable in closing and opening directions between closed and open valve positions, the apparatus comprising: a first cam system comprising: a first adjustable member engaging the stem when the stem is adjacent to the closed valve position, the first cam system being movable by the stem in a closing direction once engaged, anda first biasing member forcing the first cam system in the opening direction; a first switch capable of being actuated by the first cam system when the stem is at the closed valve position; a second cam system being integral to or separate from the first cam system and comprising: a second adjustable member engaging the stem when the stem is adjacent to the open valve position, the second cam system being movable by the stem in the opening direction once engaged, anda second biasing member forcing the second cam system in the closing direction; a second switch capable of being actuated by the second cam system when the stem is at the valve open position; and an indicator moveable by the first and the second cam systems and capable of indicating at least open, intermediate, and closed states of the valve. 12. The apparatus of claim 11, wherein the stem has an adapte r to engage the first and second adjustable members.13. The apparatus of claim 11, wherein each cam system comprises: a holder biased by a spring and capable of moving the indicator, a threaded rod on the holder, and a ring adjustably threaded on the rod. 14. The apparatus of claim 13, wherein the ring defines a split fitting into a track on the holder, the ring being adjustable by rotation of the rod.15. The apparatus of claim 11, wherein the indicator is biased in the closing direction.16. The apparatus of claim 11, wherein the indicator indicates the intermediate state in the absence of engagement of the stem with the first and second cam systems.17. The apparatus of claim 11, wherein the indicator comprises first and second visual portions, the indicator indicating neither portion for the closed valve state, indicating only one portion for the intermediate valve state, and indicating both portions for the open valve state.18. The apparatus of claim 11, wherein the indicator comprises: a first member capable of engaging the first cam system when moved by the first biasing member in the opening direction, and a second member being further disposed in the closing direction than the first member and capable of engaging the second cam system when moved by the stem in the opening direction. 19. A method for indicating states of a valve having a stem, the stem being movable in closing and opening directions between closed and open valve positions, the method comprising the steps of: a) adjusting a first cam system to engage the stem adjacent the closed valve position; b) adjusting a second cam system to engage the stem adjacent the opened valve position; c) indicating a closed-valve state by displacing the first cam system in the closing direction with the stem to the closed valve position; d) indicating an open-valve state by displacing the second cam system in the opening direction with the stem to the opened valve position; and e) indicating an intermediate-valve state in the absence of engagement of the stem with the first and second cam system by biasing the first cam system in the opening direction and biasing the second cam system in the closing direction. 20. The method of claim 19, wherein the step (a) comprises adjusting a member on a rod of the first cam system, the member capable of engaging the stem.21. The method of claim 20, wherein adjusting the member on the rod comprises rotating the rod to move a ring threaded on the rod, the ring defining a split fitting in a track on the first cam system.22. The method of claim 19, wherein the step (c) comprises displacing a visual indicator in the closing direction to a minimum level by biasing the visual indicator in the closing direction and removing counter-forces on the visual indicator.23. The method of claim 19, wherein the step (c) further comprises actuating an open-valve indication switch.24. The method of claim 19, wherein the step (d) comprises displacing a visual indicator in the opening direction to a maximum level by engaging the second cam system with the visual indicator.25. The method of claim 19, wherein the step (d) further comprises actuating a closed-valve indication switch.26. The method of claim 19, wherein the step (e) comprises displacing a visual indicator in the opening direction to an intermediate level by engaging the first cam system with the visual indicator.