Valve Stem Nut Retention Sleeve for Vibration-Lock Adjustment
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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 with 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 rotation of the stem nut, ensuring secure engagement and adjustable torque.
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 nut loosening under vibration and high-cycle conditions
Solution Approach 1:
The nut retention sleeve is designed to be movable between two positions: a first position where it engages the coupling member to lock the stem nut, and a second position where it disengages to allow adjustment. This dynamic mechanism resolves the contradiction by making the locking system itself adjustable, allowing the user to switch between secure locked state and adjustable state as needed.
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 when engaged with the coupling member, and can be moved to disengage when adjustment is needed. This intermediary mechanism allows the stem nut to be both secure and adjustable without direct conflict between these requirements.
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 engaged and disengaged positions. When locked, the stem nut is securely fixed; when the sleeve is moved to the second position, the stem nut becomes adjustable. This dynamic approach resolves the contradiction by making the security level itself controllable.
Solution Approach 2:
The nut retention sleeve serves as a mediator that can be selectively positioned to either lock or unlock the stem nut. This intermediary component provides a simple mechanism to switch between secure engagement and adjustable state, eliminating the need for complex tools or procedures to adjust the stem nut while maintaining reliability during operation.
3Reliability
If a locking mechanism is added to prevent nut loosening, then reliability is improved, but device complexity increases
Solution Approach 1:
The nut retention sleeve performs multiple functions: it acts as a locking mechanism when engaged with the coupling member, provides structural support, and can be moved to allow adjustment. This multi-functionality reduces the need for separate components, thereby minimizing added complexity while achieving reliable locking.
Solution Approach 2:
The nut retention sleeve is a simple intermediary component that adds minimal complexity to the system. Instead of requiring complex locking mechanisms or additional fasteners, this single movable sleeve provides effective locking by engaging with existing features on the coupling member, thereby achieving reliability with minimal added structural complexity.
Data Source
Figure 1
Figure 2
Figure 3A~3B
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.