Adjustable Damper Plate for Burner Ignition Noise Reduction
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Solution Overview
Problem
Pre-mixed burners in compact, high-efficiency appliances experience 'rough' or 'hard' ignitions due to rapid expansion of the gas-air mixture, leading to audible pressure oscillations and noise, which existing noise reduction methods, such as reducing blower speed or inlet restriction, often exacerbate rather than alleviate.
Innovation Solution
A variable flow control device with a damper plate positioned downstream of the blower, which increases static pressure at the burner outlet during ignition and adjusts fluid flow to reduce noise by controlling the resistance to the air/gas mixture, maintaining a consistent blower speed and higher discharge pressure while lowering gas input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If blower speed is reduced or blower inlet is restricted to match air and gas flow, then gas input rate is reduced and less pressure buildup occurs within the chamber, but blower discharge pressure is reduced which actually makes ignitions worse
Solution Approach 1:
A damper plate is introduced as an intermediary component positioned downstream of the blower outlet. This damper plate selectively restricts airflow only during ignition conditions, while leaving the blower discharge pressure unaffected during normal operation. The damper acts as a mediator that decouples the relationship between blower pressure and ignition flow rate, allowing independent optimization of both parameters.
Solution Approach 2:
The damper plate is positioned and configured in advance to create the desired flow restriction before ignition occurs. By pre-positioning the damper to restrict flow during the ignition event, the system prepares the combustion chamber conditions beforehand, preventing pressure oscillations before they can develop during the critical ignition moment.
2Object-generated harmful factors
If gas flow is reduced at ignition, then pressure buildup within the chamber is reduced, but the rapid expansion of the gas air mixture upon ignition still causes pressure spikes and audible oscillations
Solution Approach 1:
The flow restriction is applied locally at the blower outlet region rather than uniformly throughout the system. The damper plate creates a localized restriction that specifically affects the ignition mixture flow while maintaining overall system performance. This local application of flow control allows pressure oscillations to be reduced without significantly impacting the overall ignition rate or combustion efficiency.
3Temperature
If the combustion chamber is made small and flow restrictive to achieve sufficient heat transfer, then heat transfer efficiency is improved, but the rapidly expanding combustion causes chamber pressure to momentarily spike and push against the blower
Solution Approach 1:
The flow control function is segmented into two independent control zones: the combustion chamber maintains its small, flow-restrictive design for heat transfer efficiency, while the damper plate upstream at the blower outlet provides separate flow restriction control for ignition management. This segmentation allows the chamber geometry to be optimized for heat transfer without being constrained by ignition pressure issues, as the damper handles the ignition flow regulation independently.
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
Effectively reduces burner ignition noise by preventing pressure oscillations through controlled static pressure management and fluid flow adjustment, improving ignition smoothness without the need to reduce blower speed or gas flow.
Implementation Method 1
A damper plate is provided in the opening downstream of the blower for increasing a static pressure at the outlet of the blower during ignition of the burner
Implementation Method 2
An adjustable damper plate positioned downstream of the burner controls the flow of fluid from the blower to the burner
Data Source
AI summary
A flow control device for an appliance including a burner and a blower for delivering a pre-mixed mixture of air and gas to the burner includes a flange defining an opening through which the pre-mixed mixture of air and gas flows from an outlet of the blower to the burner. A damper plate is provided in the opening downstream of the blower for increasing a static pressure at the outlet of the blower during ignition of the burner.