Bi-stable Flow Restrictor for Gas Burner Mixing
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Solution Overview
Problem
Existing gas/air mixing devices for gas burners suffer from unwanted variations and oscillations in the gas/air mixture due to inconsistent flow control, leading to inefficiencies and unstable burner performance.
Innovation Solution
A bi-stable flow restrictor mechanism, comprising a pivotable flap with a spring element and a bending rod, is integrated into the gas/air mixing device, allowing for precise control of air and gas flow through venturi nozzles, ensuring a consistent mixture by switching automatically between fully opened and closed positions based on air pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flow restrictor is used to control air flow through the venturi air nozzle, then the gas/air mixture can be regulated, but unwanted variations and oscillations in the mixture occur due to inconsistent flow control
Solution Approach 1:
The flow restrictor is designed as a bi-stable mechanism with a flap that can dynamically switch between two stable positions (fully open and fully closed) rather than maintaining intermediate positions. This dynamic design with defined stable states eliminates unwanted oscillations and variations in the gas/air mixture, providing reliable flow control.
Solution Approach 2:
The system changes the flow control parameter from continuous adjustment to discrete bi-stable positions. The flap mechanism transitions between two distinct states (open/closed) controlled by the interaction between the spring element and bending rod, which stabilizes the flow control and prevents mixture variations.
2Ease of operation
If a spring element is used to provide restoring force to the flap, then the flow restrictor can return to closed position, but the system may oscillate between open and closed positions
Solution Approach 1:
The bending rod is positioned to contact the spring element before the flap reaches the fully closed position. This beforehand cushioning creates a progressive resistance that dampens the system's motion, preventing the flap from oscillating between open and closed positions by absorbing excess energy before the limit is reached.
Solution Approach 2:
The bending rod acts as an intermediary element between the spring element and the flap. It mediates the interaction by providing a progressive contact point that modifies the spring's restoring force, creating a smooth transition that stabilizes the system and prevents oscillations while still enabling the flap to return to the closed position.
3Device complexity
If the flow restrictor is designed with simple flap and spring element, then the device complexity is reduced, but reliable bi-stable operation may be difficult to achieve
Solution Approach 1:
The solution adds a spatial dimension to the spring-flap interaction by introducing the bending rod at a specific position and angle. This dimensional arrangement creates the bi-stable operation through the geometric relationship between components rather than requiring complex mechanical mechanisms, maintaining simplicity while achieving reliable bistability.
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
This solution stabilizes the gas/air mixture, preventing unwanted variations and oscillations, thereby maintaining a consistent gas/air ratio across a wide range of burner loads, from 100% to 20%, ensuring efficient and reliable burner operation.
Implementation Method 1
a spring element (29) attached with a first end (30) to the flap (27) and with a second end (31) to the housing (11)
Implementation Method 2
at least two venturi air nozzles (18, 19), wherein each venturi air nozzle (18, 19) comprises an air nozzle inlet (20, 21) and an air nozzle outlet (22, 23)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Gas/Air mixing device (10) for a gas burner, comprising a housing (11) with at least one inlet (12) for the gas, at least one inlet (13) for the air and at least one outlet (14) for the gas/air mixture; at least two venturi air nozzles (18, 19), wherein each venturi air nozzle (18, 19) comprises an air nozzle inlet (20, 21) and an air nozzle outlet (22, 23), and wherein to each air nozzle outlet (22, 23) there is assigned a gas nozzle (24, 25) so that air and gas can be mixed in the region of the air nozzle outlet (22, 23) of the respective venturi air nozzle (18, 19); at least one flow restrictor (26) assigned to at least one venturi air nozzle (18, 19) capable of shutting the flow of air through the respective venturi air nozzle (18, 19); wherein the at least one flow restrictor (26) is capable of shutting the flow of air through the respective venturi air nozzle (18, 19) and simultaneously the flow of gas through the gas nozzle (24, 25) assigned to the respective venturi air nozzle (18, 19).