Hot water apparatus
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Solution Overview
Problem
Existing hot water apparatus configurations that attach the flame rod to the side wall of the heat exchanger instead of the burner suffer from abnormal combustion detection errors due to flame lift, leading to incorrect determination of normal combustion.
Innovation Solution
The flame rod is attached to the side wall of the heat exchanger with the insulator part positioned downstream and the core wire part extending towards the burner port plate, with the tip-side part opposed to the burner ports and the extending part not opposed to any ports, ensuring accurate flame detection and preventing erroneous normal combustion determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the flame rod is attached to the side wall of the heat exchanger with the insulator part positioned downstream, then the apparatus structure is simplified and size is reduced, but abnormal combustion may cause flame to contact the extending part of the core wire part leading to erroneous detection
Solution Approach 1:
The core wire part is segmented into two distinct portions: the extending part that extends from the insulator part, and the tip-side part that is positioned closer to the tip. This segmentation allows the extending part to be positioned away from burner ports to avoid false detection during abnormal combustion, while the tip-side part remains positioned to detect normal combustion flames accurately.
Solution Approach 2:
Different portions of the core wire part are given different spatial positions and functions: the extending part is positioned to avoid contact with flames during abnormal combustion (non-detection zone), while the tip-side part is positioned to contact flames during normal combustion (detection zone). This local differentiation of quality and position enables the flame rod to distinguish between normal and abnormal combustion states.
2Measurement precision
If the tip-side part of the core wire part is positioned close to the burner port plate for accurate flame detection, then combustion detection precision is improved, but during abnormal combustion the flame may contact the extending part causing erroneous determination
Solution Approach 1:
The core wire part is divided into the extending part and the tip-side part, each serving different detection purposes. The tip-side part is positioned close to the burner port plate to detect normal combustion flames with high precision, while the extending part is positioned away from burner ports to serve as a reference that should remain non-contact during abnormal combustion.
Solution Approach 2:
The extending part of the core wire part acts as an intermediary reference element. By positioning it away from burner ports, it serves as a control point that should not be contacted by flames under normal or abnormal conditions, helping to distinguish true flame presence from abnormal flame lift phenomena.
3Reliability
If the flame rod is attached to the burner housing instead of the heat exchanger case, then flame detection reliability is improved, but the apparatus size increases and manufacturing complexity increases
Solution Approach 1:
The flame rod structure with its segmented core wire part is designed to be universally applicable regardless of attachment location. Whether attached to the burner housing or the heat exchanger case, the segmented core wire configuration ensures reliable distinction between normal and abnormal combustion, making the attachment location flexible without compromising detection reliability.
Solution Approach 2:
The flame rod structure itself provides the detection differentiation function through its own geometry and positioning. The extending part and tip-side part configuration enables the system to self-distinguish between normal and abnormal combustion states without requiring additional sensors or complex control mechanisms, simplifying the overall system while maintaining reliability.
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 configuration allows for precise detection of normal combustion and prevents mistaking abnormal combustion as normal, optimizing burner control while minimizing the apparatus size and reducing manufacturing complexity.
Implementation Method 1
The flame rod serves to detect flame of the burner using electrical conductivity of the flame, and includes a core wire part having electrical conductivity
Implementation Method 2
the heat exchanger for heating hot water, and the burner is attached with a flame rod. The burner is of a total primary air combustion type and includes a burner port plate provided with a plurality of burner ports, and a mixed gas of fuel gas and air is supplied to a back side of the burner port plate. The mixed gas passes through the plurality of burner ports to burn in a region on a surface side of the burner port plate. With the heat exchanger recovering heat from this combustion gas, hot water heating (generation of hot water) is performed.
Data Source
AI summary
A flame rod of a hot water apparatus is attached to a side wall part of a case that surrounds a combustion region such that an insulator part is positioned on a downstream side of a burner port plate of a burner in a combustion gas flow direction. A core wire part includes an extending part extending from the insulator part toward the burner port plate, and a tip-side part positioned closer to a tip of the core wire part than the extending part. In the combustion gas flow direction, the tip-side part of the core wire part is opposed to at least one of burner ports, and the extending part is not opposed to any of the burner ports.