Rotatable Volute Tongue in Centrifugal Fans for Bidirectional Airflow
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Solution Overview
Problem
Existing centrifugal fans with volute tongues cannot effectively cut air flows when the impeller rotates in reverse directions, leading to a significant decrease in air volume discharged, which affects the drying efficiency in dryers.
Innovation Solution
A centrifugal fan design with a rotatable volute tongue that can adjust between two limit positions, allowing it to cut air flows effectively in both forward and reverse impeller rotations, utilizing sealing structures and vanes to ensure consistent airflow and prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the volute tongue is fixed in position, then the centrifugal fan can effectively cut air flow when the impeller rotates in the forward direction, but the volute tongue cannot cut air flow when the impeller rotates in the reverse direction, resulting in sharp decrease in air volume discharged
Solution Approach 1:
The volute tongue is made rotatable around the impeller's rotation axis, allowing it to dynamically adjust its position according to the impeller's rotation direction. When the impeller rotates in the forward direction, the volute tongue is positioned to effectively cut air flow; when the impeller rotates in the reverse direction, the volute tongue rotates to a different position to cut the reverse air flow, thereby maintaining high air volume discharge in both rotation directions
Solution Approach 2:
The rotatable volute tongue structure enables the centrifugal fan to universally handle both forward and reverse rotation directions of the impeller. By rotating the volute tongue to appropriate positions, the fan can effectively cut air flow regardless of the impeller's rotation direction, making the fan adaptable to different operating conditions including bidirectional rotation scenarios
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
Ensures a sufficient air volume is maintained when the impeller rotates in either direction, enhancing the drying effect by maintaining airflow stability and efficiency.
Implementation Method 1
a centrifugal fan uses a high-speed rotating impeller to accelerate gas
Implementation Method 2
the volute tongue can cut an air flow driven by the impeller so that the air flow is discharged from the air outlet
Implementation Method 3
then decelerate it, and change a flow direction thereof, thus converting kinetic energy into potential energy
Data Source
AI summary
A centrifugal fan and a dryer, where the centrifugal fan includes a shell, a driving mechanism, an impeller and a volute tongue arranged in the shell, the driving mechanism is connected with the tongue and can drive the tongue to rotate between a first limit position and a second limit position, the tongue includes a first volute tongue part and a second volute tongue part; when the tongue is located at the first limit position and the impeller rotates forwards, the first tongue part abuts against the inner wall of one side of the shell in a sealed mode, the second tongue part can cut the air blown by the impeller, and when the tongue is located at the second limit position and the impeller rotates reversely, the first tongue part can cut air blown by the impeller.