Radial Fan Geometry for Quiet Cooker Hood Extraction
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Solution Overview
Problem
Existing radial fans for cooker hoods require a large axial installation space and generate significant noise due to flow separation and rotational tones.
Innovation Solution
A radial fan design with a spiral fan housing, axial intake, and radial outlet, featuring specific geometric ratios for intake and outlet areas, backward-curved impeller blades, and a pressure chamber that minimizes flow deceleration and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drum rotor fans or backward-curved radial fans are used in cooker hoods, then extraction performance is achieved, but axial installation space becomes large
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric ratio between intake cross-sectional area and outlet circumferential surface area to a specific range (0.75 ≤ A/M ≤ 1.0). This parameter optimization enables the radial fan to achieve effective extraction performance while maintaining a compact axial installation space, resolving the contradiction between productivity and compactness.
2Productivity
If conventional radial fans are used, then extraction function is provided, but noise generation increases due to flow separation and rotational tones
Solution Approach 1:
The patent optimizes flow technology parameters including the intake-to-outlet area ratio (0.75 ≤ A/M ≤ 1.0) and impeller blade geometry to minimize flow deceleration and prevent flow separation. These parameter changes significantly reduce noise-generating turbulence and rotational tones while maintaining effective extraction function.
Solution Approach 2:
The patent employs backward-curved impeller blades with specific curvature profiles that optimize flow paths. The curved blade design reduces flow separation and minimizes rotational noise generation, while the spiral fan housing geometry further optimizes flow interaction to reduce noise.
3Productivity
If backward-curved impeller blades are used, then flow efficiency is improved, but rotational noise generation increases
Solution Approach 1:
The patent carefully balances the backward-curve angle and blade geometry parameters to achieve optimal flow efficiency while controlling rotational noise. By optimizing the intake-to-outlet area ratio and blade curvature parameters within specific ranges, the patent maintains high flow efficiency and uniform velocity profiles while minimizing noise-generating flow separation.
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
The design achieves reduced noise and improved acoustic behavior by preventing flow separation and rotational tones, enhancing the interaction between the impeller and fan housing, thus optimizing airflow efficiency.
Implementation Method 1
a radial impeller (5) arranged in the fan housing (2) with impeller blades (6) arranged in a blade ring
Implementation Method 2
noise-generating flow separation in the blade channel between the individual impeller blades is prevented
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a radial blower (1) for a cooker hood with a spiral blower housing (2) having an axial intake opening (3) and an exhaust opening (4), a radial impeller (5) arranged in the blower housing (2) with impeller blades (6) arranged in a blade ring, wherein the radial impeller (5) has an axial intake (7) associated with the axial intake opening (3) and a radial exhaust (8) at the radial end of the impeller blades (6), wherein the intake (7) defines an intake cross-sectional area A in its axial plane and the exhaust (8) defines a circumferential surface area M and a ratio of the intake cross-sectional area A to the surface area M is specified such that: 0.75≤A/M≤1.0.