Fan Case Clearance Design for Motor Efficiency
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Solution Overview
Problem
Conventional air blowing devices mounted to ceilings face low motor efficiency due to larger impeller sizes required to reduce noise, leading to increased motor load and decreased performance.
Innovation Solution
The air blowing device employs a fan case design where the space between the impeller and the inner wall increases along the rotary direction, allowing for a smaller impeller size, which reduces motor load and increases efficiency, while maintaining sufficient air volume and minimizing noise disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the impeller size is increased to reduce operating noise, then the noise level is lowered, but the motor load increases and motor efficiency decreases
Solution Approach 1:
The patent changes the geometric parameters of the fan case, specifically designing the space between the impeller and fan case wall to increase gradually along the rotary direction. This parameter optimization allows the use of a smaller impeller while maintaining low noise operation, thereby resolving the contradiction between noise reduction and motor efficiency.
2Productivity
If the impeller size is increased to achieve given performance at low rotation speed, then the air blowing performance is maintained, but the motor load increases
Solution Approach 1:
The patent optimizes the fan case geometry by designing the space between the impeller and fan case wall to increase gradually along the rotary direction. This parameter change enables smaller impeller size while maintaining air blowing performance, thus improving motor efficiency without sacrificing productivity.
Solution Approach 2:
The patent divides the fan case into different sections with varying space characteristics along the rotary direction. The space is segmented to increase gradually, creating optimal flow conditions that allow smaller impeller size while maintaining performance.
3Object-affected harmful factors
If the impeller size is increased to compensate for low rotation rate, then the operating sound is reduced, but the device complexity increases
Solution Approach 1:
The patent changes the geometric parameters of the fan case rather than increasing impeller size. By designing the space to increase gradually along the rotary direction, the patent achieves low operating sound with a smaller, less complex impeller configuration.
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 achieves higher motor efficiency with reduced noise and lower power consumption by using a smaller impeller, resulting in a 30% or more electricity savings compared to conventional devices.
Implementation Method 1
The fan case includes a fan inlet communicating with the suction port and a fan outlet communicating with the blow-off port. The space between the impeller and an inner wall of the fan case increases along a rotary direction of the impeller.
Implementation Method 2
a motor for driving the impeller
Data Source
AI summary
An air blowing device includes a housing with a suction port and a blow-off port, and a fan placed in the housing. The fan includes a fan case with a tongue section, an impeller, and a motor. The fan case includes an inlet and an outlet, and is shaped such that a space between the impeller and an inner wall of the fan case increases along a rotary direction of the impeller up to a cross section cut along a line between the tongue section and its opposite section. An opening area of the fan case at the tongue section is kept equal or decreases up to the outlet.