Asymmetric Centrifugal Fan Layout for Flush Ceiling Air Conditioners
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Solution Overview
Problem
Conventional air conditioners with centrifugal fans installed in a ceiling-mounted configuration face issues with increased draft resistance, noise, and protrusion from the ceiling, leading to size constraints and environmental concerns during transportation due to interference between blowoff flows from the side and main plates, which complicates installation and handling.
Innovation Solution
The air conditioner design features a centrifugal fan with a convex-shaped boss and blades that guide airflow from the suction port to a blowoff port positioned higher than the ceiling, reducing interference and draft resistance, allowing for a flush installation and reduced noise, while the airflow guide plate separates suction and blowoff paths to prevent flow separation and noise increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a centrifugal fan with equal outer diameters for main plate and side plate is used, then the fan structure is simplified, but blowoff flows from side plate and main plate interfere with each other, increasing draft resistance and noise
Solution Approach 1:
The patent applies asymmetry by making the outer diameter of the side plate larger than that of the main plate. This asymmetric configuration prevents interference between blowoff flows from the side plate and main plate, thereby reducing draft resistance and noise while maintaining structural simplicity.
2Object-generated harmful factors
If the centrifugal fan is installed to protrude downward from the air conditioner body to avoid flow interference, then noise and draft resistance are reduced, but the ceiling panel must protrude from the ceiling surface, making size reduction difficult
Solution Approach 1:
The asymmetric design with side plate outer diameter greater than main plate outer diameter allows the fan to be installed flush with the ceiling surface without protruding downward. This configuration maintains the noise and draft resistance benefits while eliminating the need for ceiling panel protrusion.
3Object-generated harmful factors
If the suction distance between body top plate and centrifugal fan suction port is increased to reduce draft resistance, then noise is reduced, but the body height becomes undesirably large
Solution Approach 1:
Instead of increasing suction distance in the vertical dimension (which increases body height), the patent resolves the draft resistance issue by adjusting the horizontal dimension through asymmetric plate diameters. This dimensional shift allows noise and draft resistance reduction without increasing body height.
4Ease of operation
If the centrifugal fan protrudes from the body during transportation, then installation flexibility is improved, but the fan suffers damage and requires large amounts of packing materials
Solution Approach 1:
The asymmetric configuration allows the fan to be installed flush with the ceiling surface, eliminating the need for protruding installation. This provides adequate protection during transportation without requiring excessive packing materials, while still allowing installation flexibility.
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 enhances product reliability and transportability, reduces noise, and minimizes the need for packing materials, providing a compact and comfortable air conditioning solution with improved maintenance and installation efficiency.
Implementation Method 1
a centrifugal fan for sucking the air sucked via the heat exchanger, and blowing off the air to the room
Data Source
AI summary
A centrifugal fan mounted in an air conditioner has the following relationship:outer diameter of a side plate of the centrifugal fan > outer diameter of the blade rear-edge part on side-plate side > diameter of the blade rear-edge part on main plate side ≧ outer diameter of the main plate. In the centrifugal fan, the blade rear-edge part is positioned inside from a straight line connecting the connection point between the blade rear-edge part and the main plate, to the connection point between the blade rear-edge part and the side plate, as viewed from the rotation axis. The blade rear-edge part has a shape such that the distance from the rotation axis becomes larger from the main plate toward the side plate.