Outdoor Unit Top Panel Overhang to Prevent Fan Icing
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Solution Overview
Problem
Existing outdoor air-conditioning units face issues with water droplets freezing between the bell mouth and propeller fan, leading to abnormal sounds and unit stoppages due to ice formation, and previous solutions complicate manufacturing, increase costs, and impair aerodynamic performance.
Innovation Solution
An outdoor unit design featuring a casing with a top panel that overhangs forward at the edge portion corresponding to the outlet grill, preventing water droplets from freezing by directing them away from the bell mouth and propeller fan, while maintaining a simple structure and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member with width larger than the outlet opening diameter is provided above the outlet opening to prevent water droplet freezing, then water droplet freezing prevention is improved, but device complexity and manufacturing cost increase due to requiring frame-shaped rim and plate-shaped component combination
Solution Approach 1:
The patent integrates the sealing function directly into the outlet grill structure by forming the seal member as an integral part of the grill's peripheral edge, eliminating the need for separate frame-shaped rims and plate-shaped components. This merging of functions reduces structural complexity while maintaining effective sealing to prevent water droplet freezing.
Solution Approach 2:
The outlet grill is designed to serve multiple functions: it acts as both the air outlet structure and the sealing element. The peripheral edge of the grill simultaneously provides structural support and creates the seal against the bell mouth, preventing water ingress without requiring additional dedicated sealing components.
2Reliability
If fixing screws are added to close the gap at the center portion by fixing the seal member at both end portions, then sealing is improved, but appearance and workability are aggravated
Solution Approach 1:
The patent eliminates the need for visible fixing screws by extracting the fastening function from the sealing mechanism. The seal member is designed to be naturally retained by the structural geometry of the outlet grill and bell mouth interface, removing the need for additional fastening hardware that would compromise appearance and increase assembly complexity.
Solution Approach 2:
The seal member utilizes the inherent flexibility of the outlet grill's peripheral edge to achieve sealing through elastic deformation rather than rigid mechanical fastening. The grill's edge can deform to conform to the bell mouth surface, creating an effective seal without requiring screws or other rigid fastening elements.
3Ease of manufacture
If the seal member is fixed only at both end portions to reduce fixation spots, then manufacturing is simplified, but rattling or vibration occurs and sealing is compromised due to the seal member being bent in a curve
Solution Approach 1:
The patent employs a dynamic sealing approach where the seal member is designed with appropriate flexibility to adapt to variations in the outlet grill shape and bell mouth interface. This dynamic design allows the seal to maintain continuous contact and effective sealing even with minimal fixation points, while the flexibility absorbs vibrations and prevents rattling.
4Reliability
If the seal member requires a width substantially as large as its thickness, then sealing is achieved, but the fan diameter is reduced and aerodynamic performance is impaired due to the wall forming at least 10 mm below the upper surface of the outlet grill
Solution Approach 1:
The patent applies sealing only at the critical peripheral interface between the outlet grill and bell mouth, rather than requiring a wide seal member across the entire outlet opening. This localized sealing approach uses the natural geometry of the peripheral edge to create an effective seal with minimal intrusion into the air course, preserving fan diameter and aerodynamic performance.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In the outdoor unit including: a casing (1) having a substantially parallelepiped shape opened on top; a top panel (15) configured to close the opening on the top of the casing (1); a bell mouth (7) provided at an outlet opening of a propeller fan (30) formed on a front panel (3) which constitutes the casing (1); an outlet grill (8) attached on the front side of the outlet opening; and an appentice (16) provided at an end portion of the top panel (3) at a portion corresponding to the outlet grill (8) on the front side of the top panel (3) so as to be overhung to the front from the edge portion.