Combustion Box Electrode Sealing Using Water Tube Restraint
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Solution Overview
Problem
Conventional heat source apparatuses experience poor sealing properties due to the expansion of packing materials during compression, which reduces the compression stress and allows combustion gas to leak.
Innovation Solution
The integration of water tubes on the side plate of the combustion box, which contact the packing to prevent expansion, enhancing compression stress and achieving better sealing by positioning water tubes either on the inside or outside surfaces and using inclined swelled-out portions to manage compression forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamp is fastened to compress the packing between the flange portion and the side plate, then the electrode component is securely mounted, but the packing expands in the peripheral direction reducing compression stress and sealing properties
Solution Approach 1:
The water tubes are positioned at specific locations (upper and lower sides) of the electrode component mounting position to provide localized restraint. This creates different functional zones: the water tubes provide restraint where needed to prevent packing expansion, while other areas maintain their original functions. The side plate is thus divided into functional zones with different properties.
Solution Approach 2:
The water tubes act as intermediary elements that mediate between the clamp compression force and the packing material. Instead of the clamp directly compressing the packing (which causes expansion), the water tubes serve as intermediate structures that the packing contacts, providing restraint while distributing the compression force more effectively.
2Object-generated harmful factors
If the packing is compressed to improve sealing, then combustion gas leakage is reduced, but the packing expands peripherally reducing the compression stress inside
Solution Approach 1:
The water tubes create localized restraint zones at the upper and lower edges of the packing. This allows the packing to be compressed effectively in the radial direction (improving sealing) while the water tubes prevent peripheral expansion that would reduce compression stress. The local restraint maintains compression stress where it is most needed for sealing.
Solution Approach 2:
The water tubes serve as intermediary structures between the packing and the external environment. They provide a physical barrier that prevents the packing from expanding outward while allowing the compression force to be maintained. This intermediary restraint system solves the contradiction between compression and expansion.
3Reliability
If water tubes are disposed on the side plate to prevent packing expansion, then sealing properties are improved, but the device complexity increases
Solution Approach 1:
The water tubes serve multiple functions: they are part of the water jacket system for cooling the combustion box, and they simultaneously act as restraint structures to prevent packing expansion. This multi-functionality means that adding the water tubes does not purely increase complexity, as they fulfill both cooling and sealing reinforcement roles.
Solution Approach 2:
The invention merges the water jacket cooling system with the packing restraint system. The water tubes that would normally only serve cooling purposes are positioned and configured to also provide mechanical restraint to the packing. This combines two functional systems into a unified structure, reducing overall device complexity compared to having separate cooling and restraint systems.
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 effectively prevents packing expansion during compression, ensuring high internal compression stress and maintaining good sealing properties, thereby enhancing the overall sealing efficiency of the heat source apparatus.
Implementation Method 1
a water jacket disposed in that portion of the combustion box which lies between the burner and the heat exchanger, the water jacket being connected to the heat exchanger in order to cool the combustion box
Implementation Method 2
the compression stress inside the packing cannot be enhanced sufficiently, resulting in poor sealing properties
Data Source
AI summary
In a heat source apparatus in which an electric component having an electrode and an insulator is mounted on a side plate of a combustion box, in a state in which a packing is interposed between a flange portion of the insulator and the side plate, by fastening to the side plate a clamp which overlaps with an outer surface of the flange portion, the packing is prevented from getting spread when compressed, thereby securing good sealing properties.Upper and lower water tubes constituting a part of a water jacket are disposed on a side plate on upper and lower sides of the mounting position of the electrode component. In case the upper and lower water tubes are disposed on an inside surface of the side plate, upper and lower side edge portions of the packing are in contact with those upper and lower swelled-out portions formed in the one-side side plate which are swollen outward for respectively receiving into recesses the upper and lower water tubes; and that, in case the upper and lower water tubes are disposed on an outside surface of the side plate, upper and lower side edge portions of the packing are in contact with the upper and lower water tubes.