Water heater
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Solution Overview
Problem
The existing water heater designs with all primary air combustion type burners face issues with increased flow resistance and complexity due to the use of multiple sealing members, which complicates assembly and maintenance, especially when dealing with acid vapor backflow prevention.
Innovation Solution
A water heater design featuring a single annular packing for airtight sealing between the fan casing and the vessel, combined with a check valve having a flange portion and specific step portions for easy fitting, reduces the number of components and flow resistance by eliminating the need for an O-ring on the check valve, thus preventing acid vapor backflow and maintaining airtightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sealing members (sealing packing and O-ring) are used to prevent acid vapor leakage, then airtightness is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent combines multiple sealing functions into a single sealing ring that integrates both the sealing packing and O-ring functions. This single sealing component is installed in a groove at the connection between the upstream connecting pipe and downstream connecting pipe, eliminating the need for separate sealing members while maintaining comprehensive airtightness against acid vapor leakage.
Solution Approach 2:
The single sealing ring performs multiple sealing functions simultaneously: it seals the connection between connecting pipes and prevents acid vapor leakage at the check valve interface. This multi-functional design reduces the total number of components while maintaining reliable protection against acid vapor infiltration.
2Reliability
If check valve is disposed in upstream connecting pipe for acid vapor prevention, then protection of fan casing is improved, but flow resistance increases
Solution Approach 1:
The check valve is positioned specifically at the upstream end of the upstream connecting pipe, where acid vapor backflow is most likely to occur. This localized placement provides effective protection at the critical point while minimizing interference with the overall gas flow path, thereby reducing flow resistance compared to more extensive sealing arrangements.
3Ease of manufacture
If check valve with flange portion and step portions is used, then ease of assembly is improved, but device complexity increases
Solution Approach 1:
The check valve is pre-equipped with a flange portion and step portions during manufacturing. The flange portion extends outward to align with the groove position, and the step portions are pre-formed to guide the sealing ring into place. These preliminary structural features simplify the assembly process by providing built-in alignment and positioning mechanisms.
Solution Approach 2:
The sealing ring is nested within the groove formed by the flange portion and step portions of the check valve. This nested arrangement allows the sealing ring to be securely positioned within the check valve structure, creating a compact integrated assembly that is easier to install as a single unit.
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 design simplifies assembly, reduces flow resistance, and effectively prevents acid vapor from reaching the fan and mixing device, enhancing the reliability and efficiency of the water heater while maintaining airtightness without increasing the number of components.
Implementation Method 1
an annular packing connecting a first connection end surface at a downstream end of a first passage forming a downstream-side passage of the fan casing with a second connection end surface at an upstream end of a second passage forming a upstream-side passage of the vessel in airtight state
Implementation Method 2
a check valve disposed near the upstream end in the second passage... when the fan stops, the acid vapor generated in and ascending from the vessel (40) is blocked by the check valve (4), whereby the flow of the acid vapor into the upstream fan casing (41) and mixing device (42) can be prevented
Implementation Method 3
a fan for supplying a mixture gas of primary combustion air and fuel gas to the burner... When the fan rotates, the mixture gas obtained by mixing the air and the fuel gas in the mixing device (42) is fed to the vessel (40) provided with the burner (3a)
Implementation Method 4
all the air taken in through an air supply passage (43) by rotating a fan (not shown) in a fan casing (41) is fed as primary combustion air to a mixing device (42) and the air is mixed with fuel gas supplied through a gas supply passage (44)... a mixture gas obtained by mixing is fed to a reverse-combustion type burner (3a)
Implementation Method 5
the primary heat exchanger (311) recovers sensible heat when the combustion exhaust gas is fed to the primary heat exchanger (311), and the secondary heat exchanger (321) recovers latent heat when the combustion exhaust gas is fed to the secondary heat exchanger (321)
Implementation Method 6
part of the combustion exhaust gas recovered the latent heat by the secondary heat exchanger (321) condenses into acid drain to remain in the secondary heat exchanger (321)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A water heater includes a vessel (20) provided with a burner (3) having a downward combustion surface, a fan casing (10) accommodating a fan (10a) for supplying a mixture gas of primary combustion air and fuel gas to the burner, an annular packing connecting a first connection end surface at a downstream end of a first passage forming a downstream-side passage of the fan casing with a second connection end surface at an upstream end of a second passage forming an upstream-side passage of the vessel in airtight state, and a check valve (5) disposed near the upstream end in the second passage (2).