Non-Uniform Drive Key for Misaligned Rotary Ball Valves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotary valve systems in twin bed treatment systems face challenges with hysteresis and irregular seal compression due to center line misalignment and tolerance stack-ups, leading to delayed or non-uniform rotation of ball valves and potential leakage.
Innovation Solution
A rotary valve design incorporating a drive key with non-uniform thickness, thinner at the middle and thicker at the ends, which allows for slight offset alignment of slotted openings to reduce hysteresis and prevent irregular compression, ensuring proper seal registration and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform thickness drive key is used to connect ball valves, then the structure is simple and easy to manufacture, but center line misalignment and tolerance stack-ups cause hysteresis and irregular seal compression
Solution Approach 1:
The drive key incorporates varying thickness along its length, with the middle section being thinner than the end sections. This local variation in geometry compensates for center line misalignment and tolerance stack-ups, ensuring uniform seal compression across all ball valves while maintaining manufacturing simplicity.
2Ease of operation
If separate valve members and actuators are provided for each bed, then each valve can be independently controlled, but the system complexity increases
Solution Approach 1:
Multiple ball valves are connected through a common drive key that passes through all valve stems. This merging approach allows synchronized operation of multiple valves through a single drive mechanism, reducing system complexity while maintaining the ability to control each bed independently through the rotary valve assembly.
3Adaptability or versatility
If the drive key thickness is reduced to accommodate misalignment, then center line offset is tolerated, but hysteresis increases due to excessive clearance
Solution Approach 1:
The drive key features a non-uniform thickness profile where the middle section is thinner to accommodate center line misalignment, while the end sections maintain greater thickness. This localized thinning provides the necessary clearance for misalignment without creating excessive overall clearance that would cause hysteresis and delayed valve response.
Data Source
AI summary
A rotary valve includes a first ball valve including a first stem extending from a first proximal stem end to a first distal stem end outward from the first ball valve. The first stem including a first slotted opening extending from the first distal stem end into the first stem. The rotary valve includes a second ball valve including a second stem extending from a second proximal stem end to a second distal stem end outward from the second ball valve. The second stem including a second slotted opening extending from the second distal stem end into the second stem. The second stem extends towards the first stem. The rotary valve includes a drive key of non-uniform thickness located within the first slotted opening and the second slotted opening. The drive key operably connects the first ball valve to the second ball valve.