Method and system for controlling a flow curve of an electromechanical gas valve
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Solution Overview
Problem
Variable gas valves for cooking appliances exhibit non-linear flow curves, leading to imprecise control over heating output, which can result in poor cooking performance due to uneven changes in heating as the control knob is rotated across its range of positions, especially when used with burners of different sizes.
Innovation Solution
A cooking appliance system that includes electromechanical valves, flow meters, and a controller to regulate gas flow, providing linear flow curves by mapping the position of manually-actuated control knobs to valve settings, allowing precise control of gas burners regardless of size or type, and optionally detecting gas leaks or tracking consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a variable gas valve is used to control gas flow to cooking elements, then the heating output can be varied between maximum and minimum positions, but the flow curve is non-linear resulting in uneven changes in heating output relative to control knob movement
Solution Approach 1:
The patent replaces the purely mechanical valve system with an electromechanical system that includes a motor, controller, and feedback sensors. The controller receives input from the control knob position and adjusts the valve actuator accordingly, substituting mechanical direct connection with an electronic control system that can compensate for non-linearities through software algorithms.
Solution Approach 2:
The patent implements feedback mechanisms including position sensors that detect the actual valve position and flow meters that measure actual gas flow rate. This feedback is fed back to the controller which adjusts the valve actuator to achieve the desired linear flow curve, compensating for deviations caused by the non-linear mechanical characteristics of the valve plug and flow path.
2Adaptability or versatility
If a valve is designed to support a larger, higher output cooktop burner, then maximum flow rate is sufficient, but the valve has little effect on flow rate through a substantial portion of its range when used with smaller, lower output burners
Solution Approach 1:
The patent makes the valve system dynamic by implementing electronic control that can adapt to different burner configurations. The controller can receive input about burner size or type and adjust the flow curve characteristics accordingly, or use feedback from flow meters to dynamically adjust the valve position to maintain effective control across the full range of operation regardless of burner size.
Solution Approach 2:
The patent changes the operational parameters of the valve through electronic control, allowing the same physical valve to operate with different effective flow characteristics. The controller can modify the relationship between control knob position and valve opening degree, effectively changing the flow curve parameters to match the requirements of different burner sizes, thereby maintaining control effectiveness across various applications.
3Ease of manufacture
If the flow curve is fixed by machining the valve plug, then manufacturing is simplified, but the flow curve cannot be adjusted for different burner sizes or applications
Solution Approach 1:
The patent replaces the fixed mechanical flow curve determination (based on valve plug machining) with an electronic control system. Instead of relying solely on physical geometry to define the flow characteristics, the system uses a motorized actuator and controller that can electronically adjust the valve opening degree, effectively creating an adjustable flow curve without requiring different physical valve components for different applications.
Data Source
AI summary
A cooking appliance includes, a gas cooking element; an electromechanical valve fluidly coupled with the gas cooking element to regulate a flow of gas to the cooking element; a manually-actuated user control movable over a range of positions; and a controller coupled to the user control and the electromechanical valve, the controller configured to determine a position of the manually-actuated user control within the range of positions and to control the electromechanical valve based at least in part upon the determined position to provide a controlled flow curve for the gas cooking element over the range of positions of the user control.