Rotary Valve Position Sensing from an Indeterminate Start State
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Solution Overview
Problem
Valves with indeterminant starting states pose challenges in determining their rotational position and fluid flow regulation, especially in partially open states, due to the lack of clear mechanical stops and reference positions.
Innovation Solution
A valve control system incorporating a rotatable valve coupled with a motor, a valve position indicator, and at least two sensing devices (home and end-of-travel position sensing devices) that use Hall effect technology to detect magnets, allowing a controller to determine the valve's state through logic that monitors and interprets sensor status before and after rotation stops, preventing over-travel and accurately positioning the valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a valve is initialized without mechanical stops or reference positions, then the valve structure is simpler and more adaptable, but the starting state becomes indeterminant and difficult to detect
Solution Approach 1:
The patent replaces mechanical stops and reference positions with a magnetic field-based sensing system. Hall effect sensors detect the position of a magnetic indicator attached to the valve closure element, eliminating the need for mechanical reference features while maintaining precise position detection capability.
Solution Approach 2:
The patent introduces a magnetic indicator as an intermediary between the valve closure element and the Hall effect sensors. This magnetic indicator carries position information that can be detected without mechanical contact, allowing the sensors to determine valve state indirectly through magnetic field interaction.
2Device complexity
If a single sensing device is used to detect valve position, then the device complexity is reduced, but the reliability of valve state determination decreases
Solution Approach 1:
The patent places multiple Hall effect sensors at different angular positions around the valve housing. Each sensor monitors a specific sector of the valve's rotational range, allowing the system to determine valve state by evaluating which sensor detects the magnetic indicator, thereby improving reliability through distributed detection.
3Speed
If the valve closure element rotates without reference positions, then the valve operation is smoother and faster, but the precision of position measurement deteriorates
Solution Approach 1:
The patent replaces mechanical reference positions with a magnetic field-based detection system that can precisely determine angular position without physical contact. The Hall effect sensors detect the magnetic indicator's position continuously, enabling precise measurement while maintaining smooth, high-speed rotation without mechanical interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively determines and maintains the valve's state, reducing the risk of indeterminant states during operation and initialization, ensuring precise control and preventing mechanical errors like springing after stops.
Implementation Method 1
at least two sensing devices (home and end-of-travel position sensing devices) that use Hall effect technology to detect magnets
Data Source
AI summary
A valve control system includes a rotatable valve operably coupled to a motor, a valve position indicator configured to rotate with the rotatable valve, at least two sensing devices configured to detect the valve position indicator, and a controller. The at least two sensing devices include a home position sensing device and an end-of-travel position sensing device. The controller includes valve state determination logic having circuitry configured to monitor a status of a home indicator and an end-of-travel indicator of the rotatable valve, determine a commanded direction of movement of the rotatable valve, monitor the status of the home indicator and the end-of-travel indicator before a valve rotation stop is commanded and after the valve rotation stop is commanded, and determine a current state of the rotatable valve based on the commanded direction of movement and at least one of the status of the home indicator and the end-of-travel indicator.