Actuated Valve Coupling Sleeve for Locking an Adjustable Stem Nut
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Solution Overview
Problem
In rapid or high cycle applications, or in valves exposed to vibration, the actuator stem nut tends to loosen, leading to leakage and increased wear of stem sealing components in flow control devices like rotary valves.
Innovation Solution
An actuated valve assembly incorporating a nut retention sleeve that is slideable between a nut retaining position to rotationally fix the stem nut with a coupling member and a nut adjusting position to permit adjustment of the stem nut, ensuring secure engagement and alignment, and a biasing member to maintain the sleeve in the retaining position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the stem nut is allowed to rotate freely for adjustment, then ease of operation is improved, but reliability deteriorates due to loosening under vibration and rapid cycling
Solution Approach 1:
The nut retention sleeve is designed to be movable between two states: a locked position where it prevents rotation of the stem nut, and an unlocked position where it allows rotation. This dynamic mechanism enables the system to switch between securing the stem nut during operation and allowing adjustment when needed, resolving the contradiction between reliability and ease of operation
Solution Approach 2:
The nut retention sleeve acts as an intermediary component between the stem nut and the coupling member. It provides the locking function without directly constraining the stem nut permanently, allowing for both secure retention during operation and controlled adjustment when the sleeve is moved to the unlocked position
2Reliability
If the stem nut is tightly secured to prevent loosening, then reliability is improved, but ease of operation worsens due to difficulty in adjustment
Solution Approach 1:
The system uses a dynamic locking mechanism where the nut retention sleeve can be moved between locked and unlocked positions. During normal operation, the sleeve is in the locked position providing secure retention. When adjustment is needed, the sleeve is moved to the unlocked position, allowing easy rotation of the stem nut without permanent constraints
3Reliability
If a locking mechanism is added to prevent stem nut loosening, then reliability is improved, but device complexity increases
Solution Approach 1:
The nut retention sleeve serves multiple functions: it acts as a locking mechanism to prevent loosening, provides a means for adjustment by being movable, and maintains alignment between components. By combining these functions into a single component, the design achieves improved reliability without proportionally increasing complexity
Solution Approach 2:
The nut retention sleeve is a simple intermediary component that mediates between the stem nut and coupling member. Rather than using a complex dedicated locking device, this intermediate element provides locking functionality through its ability to engage and disengage from the stem nut, keeping the overall mechanism relatively simple
Data Source
AI summary
An actuated valve assembly includes a valve, an actuator, and a nut retention sleeve. The nut retention sleeve has a first bore portion sized to closely receive and rotate with a portion of a coupling member extending from the actuator and a second bore portion sized to closely receive and rotate with at least a portion of a stem nut assembled with a valve stem of the valve. The nut retention sleeve is slideable between a nut retaining position in which the second bore portion engages the stem nut to rotationally fix the stem nut with the coupling member, and a nut adjusting position in which the second bore portion is disengaged from the stem nut to permit rotation of the stem nut on the valve stem.