Premixing device and combustion device including the same
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Solution Overview
Problem
Conventional premixing devices face issues with maintaining the desired gas mixture ratio due to potential fuel gas leakage from the first fuel gas outlet and reverse air flow, leading to increased manufacturing costs and susceptibility to foreign objects, which complicates the operation of the flapper mechanism.
Innovation Solution
A premixing device with a flapper that simultaneously opens and closes both the first flow path and fuel gas outlet, using a single flapper to manage air flow rates, reducing exposure to foreign objects, and optimizing the flapper's position to stabilize negative pressure for efficient fuel gas discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single flapper is used to open and close the first flow path, then the device complexity is reduced, but fuel gas may continue to flow from the first fuel gas outlet or air may flow reversely into it, compromising the gas mixture ratio
Solution Approach 1:
The patent merges the functions of controlling the first flow path and the first fuel gas outlet into a single flapper mechanism. The flapper is positioned to simultaneously block both the flow path and the fuel gas outlet when closed, eliminating the need for separate control components while ensuring complete shutdown of fuel flow and preventing reverse air flow.
Solution Approach 2:
The flapper is designed to close the first fuel gas outlet before the first flow path when transitioning to the closed state. This preliminary action ensures that fuel gas flow is stopped first, preventing any potential leakage or reverse flow into the outlet, thereby maintaining precise gas mixture ratios.
2Manufacturing precision
If an additional flapper is provided to open and close the first fuel gas outlet, then the gas mixture ratio is maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of controlling the first flow path and the first fuel gas outlet into a single flapper mechanism. The flapper is positioned to simultaneously block both the flow path and the fuel gas outlet when closed, eliminating the need for separate control components while ensuring complete shutdown of fuel flow and preventing reverse air flow.
Solution Approach 2:
The single flapper is designed to perform multiple functions: controlling the first flow path, blocking the first fuel gas outlet, and preventing reverse air flow. This multi-functional design eliminates the need for additional components while maintaining precise control over the gas mixture ratio.
3Ease of operation
If the flapper is positioned to expose it to air flow, then it can effectively control the flow path, but it becomes susceptible to foreign objects causing malfunction or jamming
Solution Approach 1:
The patent introduces a protective cover as an intermediary element between the air flow/foreign objects and the flapper. The cover allows air to pass through to the flapper while blocking foreign objects, enabling the flapper to respond to air flow for control purposes while being protected from contamination that could cause malfunction or jamming.
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 solution enhances the turndown ratio and maintains a consistent gas mixture ratio by preventing unnecessary fuel gas leakage and reducing the risk of foreign object interference, thus simplifying the device configuration and lowering manufacturing costs.
Implementation Method 1
a negative pressure acts on the first and second fuel gas outlets, causing fuel gas to flow out from the first and second fuel gas outlets into the premixing flow path
Data Source
AI summary
A premixing device A includes: a premixing flow path 3 including first and second flow paths 3a, 3b a extending in an upper-lower height direction in parallel arrangement in a horizontal direction; and first and second fuel gas outlets 80a, 80b; and a flapper 5. The flapper 5 is provided to be able to swing in the upper-lower height direction on an upper side of a predetermined plate part 41a and a specific flow path region 3a′, swings by using self-eight as a downward force and an air flow from below the specific flow path region 3a upward as an upward force, and is able to simultaneously open and close both the first fuel gas outlet 80a and the specific flow path region 3a in accordance with a flow rate of the premixing flow path 3.