Backflow Safety Valve Rib Structure for Hydrogen Ignition Noise
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Solution Overview
Problem
Existing reverse current protection devices for heaters, particularly when using hydrogen as fuel, suffer from high ignition noise and increased risk of flashback due to high pressure rise rates and flame speed, leading to potential damage and operational issues.
Innovation Solution
A backflow protection device with a movable backflow flap and a web structure featuring indentations and arcuate contours that minimize contact surface area during pressure surges, providing stability and reducing ignition noise, and incorporating multiple webs for enhanced stability and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the backflow preventer rests on struts perpendicular to the gas-air mixture flow path, then stability is improved, but pressure drop increases and flow noises increase
Solution Approach 1:
The strut is designed with non-uniform thickness: thicker at the upstream end for stability and thinner at the downstream end to reduce pressure drop. This local variation in geometry allows different sections of the strut to serve different functions - the upstream portion provides structural support while the downstream portion minimizes flow resistance.
Solution Approach 2:
The strut features a curved profile rather than a straight perpendicular extension. The curvature allows the strut to gradually transition from a stable vertical position to a more flow-aligned orientation, reducing abrupt pressure drops while maintaining stability during ignition events.
2Stability of the object's composition
If the backflow preventer rests on struts during ignition, then stability is improved, but ignition noises increase due to pressure wave buildup
Solution Approach 1:
The strut is designed to be dynamically responsive to pressure changes during ignition. The flexible material and optimized geometry allow the strut to bend and move in response to ignition pressure waves, preventing rigid contact that would amplify noise while maintaining stability during normal operation.
Solution Approach 2:
The strut incorporates features that cushion pressure wave buildup before it reaches harmful levels. The tapered geometry and flexible material absorb and dissipate pressure energy during ignition, preventing the buildup that would otherwise cause loud ignition noises.
3Adaptability or versatility
If smaller flow openings are used for hydrogen burning, then hydrogen combustion is enabled, but pressure drop increases
Solution Approach 1:
The strut geometry parameters are optimized to work with smaller flow openings. The non-uniform thickness and curved profile are specifically designed to minimize pressure drop in configurations with reduced flow passage areas, enabling hydrogen combustion while maintaining adequate pressure delivery.
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 effectively minimizes ignition noise and prevents backflow, ensuring component safety and efficient operation, especially when using hydrogen or hydrogen-rich gas mixtures, by absorbing pressure energy and reducing whistling or humming noises.
Implementation Method 1
The backflow damper bends into the recesses against the main flow direction of the gas-air mixture, i.e., in the backflow direction
Implementation Method 2
The ribs have recesses between the contact points into which the backflow damper can be bent and thus brought into contact with the ribs not only at the contact points but also in the area of the recesses
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a backflow protection device for a heating appliance with a backflow flap held on a bracket, wherein the backflow flap is movable relative to the bracket in order to open a flow path for a fuel-air mixture to be supplied to a burner of the heating appliance in one flow direction and to close it in a backflow direction, and with a rib structure formed from a plurality of ribs which, viewed in the backflow direction, form upstream support points for the backflow flap to limit movement of the backflow flap in the backflow direction, wherein the ribs between the support points have recesses into which the backflow flap can be bent and thereby brought into contact with the ribs next to the support points as well as in the area of the recesses.