Fan System Backflow Blocker to Reduce Flow Losses and Noise
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Solution Overview
Problem
Conventional fan systems experience significant flow losses and noise generation due to backflow and narrow duct geometries, which are exacerbated by the use of guide wheels and intermediate walls, leading to increased installation space and construction costs.
Innovation Solution
A compact mechanical backflow blocker is introduced, designed to reduce or suppress backflow by blocking part of the flow cross-section centrally in the flow path, with a flat or box-like shape that matches the duct's cross-section, allowing the fan motor to protrude into a recess and maintaining a minimal axial frame size, thereby reducing flow losses and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If guide wheels are used to remove angular spin from the flow, then flow losses are reduced considerably, but construction costs increase and noise emission is increased
Solution Approach 1:
The invention extracts and eliminates the guide wheel component from the system entirely. Instead of using a guide wheel to remove angular spin, the patent employs a backflow suppressor that directly addresses the root cause of flow losses through a simpler structural means, thereby reducing construction costs while maintaining energy efficiency.
Solution Approach 2:
The backflow suppressor is designed as a simple, inexpensive structural element compared to the complex and costly guide wheel mechanism. This disposable-like simplicity in design allows for cost-effective implementation while achieving the desired flow control function.
2Loss of energy
If guide wheels are used to stabilize air flow, then flow losses are reduced, but noise emission is increased
Solution Approach 1:
The invention removes the guide wheel component that generates noise while maintaining the flow stabilization function through the backflow suppressor. The suppressor achieves flow control through a quieter mechanism that does not involve the rotating elements of guide wheels.
3Stability of the object's composition
If intermediate walls are provided to form narrow annular ducts for uniform flow distribution, then flow distribution is improved, but flow losses increase and axial installation space is increased
Solution Approach 1:
The invention eliminates the intermediate walls and narrow annular ducts structure. Instead, the backflow suppressor directly suppresses backflow in the central area, achieving uniform flow distribution without the energy losses and space requirements associated with the intermediate wall configuration.
Solution Approach 2:
The invention shifts the approach from modifying the radial duct geometry (intermediate walls) to addressing the axial backflow directly. The backflow suppressor operates in the axial dimension to prevent recirculation, thereby achieving flow uniformity without constraining the radial flow paths.
4Object-generated harmful factors
If intermediate walls with sound-insulating material are used, then sound insulation is improved, but flow losses increase
Solution Approach 1:
The invention removes the intermediate walls entirely, eliminating the conflict between sound insulation and flow losses. The backflow suppressor provides flow control without requiring sound-insulating materials that would impede airflow.
5Area of stationary object
If the duct cross section is made small relative to fan diameter, then installation space is reduced, but flow losses increase due to backflow
Solution Approach 1:
The backflow suppressor is positioned upstream in the flow path to prevent backflow before it can develop and cause energy losses. By acting in advance to suppress the recirculation tendency, the system can operate efficiently even with compact duct dimensions.
Data Source
AI summary
A disclosed fan system includes a housing having side walls, an inflow side, and an outflow side; a fan secured in the housing by a mounting; and a backflow blocker mounted to the side walls within the housing on the outflow side of the housing partially blocking a cross-sectional area of the outflow side. The backflow blocker is positioned approximately centrally in a flow path of the housing and is configured to block part of an airflow cross section such that, between side walls of the housing and side walls of the backflow blocker, an annular duct is formed as an air passage. Further, the backflow blocker has a thickness that is greater than 5% of a width of the housing, and is less than 20% of an axial design height of the fan system.