Fan assembly and water heater
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Solution Overview
Problem
Existing fan assemblies in water heaters with exhaust suction and combustion systems face a challenge in reducing size without compromising blowing capability, particularly when the fan and exhaust tube are positioned close to each other, leading to backflow and decreased performance.
Innovation Solution
The fan assembly design includes a tongue portion that extends from one end of the boundary between the fan case and emission connection portion to a position reaching the virtual straight line connecting the emission port's center and the rotation shaft's center, optimizing the emission port's location to minimize backflow and maintain blowing capability, while allowing for a reduction in size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the fan and exhaust tube are positioned close to each other to reduce water heater size, then the device size is reduced, but the fan's blowing capability deteriorates due to backflow
Solution Approach 1:
The fan case internal space is segmented into a first internal space and a second internal space by the tongue portion. This segmentation creates distinct flow zones that prevent backflow from the emission connection portion from entering the impeller region, thereby maintaining fan blowing capability while allowing compact positioning of the exhaust tube.
Solution Approach 2:
The tongue portion acts as an intermediary structure between the fan case and emission connection portion. It extends to reach the virtual straight line connecting the emission port center and rotation shaft center, creating a flow barrier that mediates the interaction between the two components and prevents harmful backflow while enabling compact design.
2Adaptability or versatility
If the exhaust tube diameter is decreased to fit in the existing exhaust pipe, then the installation flexibility is improved, but the combustion stability deteriorates
Solution Approach 1:
The tongue portion serves as an intermediary flow control structure that compensates for the reduced exhaust tube diameter. By preventing backflow and optimizing the gas flow path from the fan to the exhaust tube, it ensures stable combustion performance even with the smaller exhaust tube diameter required for installation in existing exhaust pipes.
3Ease of manufacture
If the tongue portion does not extend to the virtual straight line position, then the manufacturing complexity is reduced, but backflow occurs and blowing capability deteriorates
Solution Approach 1:
The tongue portion is designed to extend preliminarily to the virtual straight line position to prevent backflow before it can occur. This preliminary anti-action approach ensures that the flow barrier is in place to counteract the backflow tendency caused by the compact arrangement, maintaining blowing capability without requiring complex additional components.
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 effectively suppresses backflow and maintains the fan's blowing capability, enabling the fan assembly and water heater to be reduced in size without performance loss, while also reducing noise and stabilizing combustion operations.
Implementation Method 1
as the impeller rotates, gas such as air is suctioned through the suction port and suctioned gas is emitted through the emission port
Implementation Method 2
the tongue portion is provided to extend to a position at least reaching a virtual straight line connecting a center point of the emission port and a center of rotation of the rotation shaft to each other... the backflow around the tongue portion can be suppressed
Data Source
AI summary
A fan assembly includes a fan and an emission connection portion. The fan includes a fan case having a first internal space, an impeller, and a rotation shaft. The emission connection portion includes a connection portion case having a second internal space and provided with an emission port for emitting gas sent from the fan to the outside of the fan assembly through the second internal space. In a plan view from a direction of axis of the rotation shaft, a tongue portion extending from one end toward the other end is located at a boundary between the first internal space and the second internal space, and the tongue portion is provided to extend to a position at least reaching a straight line connecting a center point of the emission port and a center of rotation of the rotation shaft to each other, from one end toward the other end.