Term
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Definition
- Provide a means to open or close a valve from a remote station through use of an electric motor
- Allows for local operation, can provide indication of valve position and interlocks to prevent valve overtravel and/or over-torquing
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Term
| Advantages of limitorque valves |
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Definition
| Allow remote and local operation of valves |
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Term
| Purpose of drive sleeve subassembly |
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Definition
| Contains the stem nut which is locked in horizontal plane so that the circular motion of the drive sleeve will cause the valve stem to rise or be lowered - and effectively control the valve disc position |
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Term
| Worm Shaft & Belleville Spring Pack |
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Definition
| Consists of the worm, associated gearing and thrust spring pack assembly |
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Term
| Handwheel & Declutch Shaft Assembly |
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Definition
| Consists of components necessary to shift operation from motor to handwheel |
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Term
| Torque Switch Subassembly |
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Definition
| Works in conjunction to spring pack assembly to trip motor under end-of travel or fault conditions |
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Term
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Definition
| Used for almost any purpose that depends on, or needs to control valve position |
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Term
| Functions of limit switches |
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Definition
- Provide positin indication,
- Interlocks (pump & valve),
- Prevent driving valve against backseat when opening,
- Backup to torque switch when closing
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Term
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Definition
- insures valve is seated with enough force to stop flow,
- protects motor and limitorque assembly should motion become bound or restricted
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Term
| How does torque switch operate? |
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Definition
- When travel is obstructed the valve stem and worm GEAR will stop turning,
- The worm will walk on its shaft and compress the spring pack assembly - converting motion into thrust force,
- When desired thrust force is reached, sleeve will be displaced and torque switch contacts will open - de-energizing motor
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