Portable electric blower with low reaction torque
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Solution Overview
Problem
Portable electric blowers experience significant reaction torque on the user's hand due to the thrust force of the airflow, leading to muscle fatigue and reduced comfort during use, as existing designs cannot dynamically compensate for the varying torque generated by the airflow.
Innovation Solution
A portable blower design featuring an axial fan with a handle positioned at the midpoint of equilibrium and an air intake nozzle with a network of directional channels that homogenize the intake airflow, providing a directional component opposite to the fan axis, which counteracts the torsional torque by modifying the air flow's orientation and velocity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the handle is positioned at the midpoint of equilibrium to balance the blower's mass, then the blower is easier to carry and maneuver, but the reaction torque from the airflow thrust increases muscle fatigue during operation
Solution Approach 1:
The suction nozzle is angled at 45 degrees relative to the fan axis, creating an asymmetric airflow intake configuration. This asymmetric design shifts the reaction force vector from the fan axis, generating a counter-torque that opposes the torque from the blowing nozzle, thereby reducing the net reaction torque on the user's hand while preserving balanced carrying characteristics
2Productivity
If the suction nozzle is aligned with the fan axis to optimize airflow efficiency, then the blowing performance is improved, but the reaction forces from intake and exhaust align to increase torque on the user's hand
Solution Approach 1:
The suction nozzle is deliberately misaligned at 45 degrees to the fan axis, creating asymmetric airflow paths. This asymmetry causes the intake reaction force to act at an angle, generating a counter-torque component that offsets the torque from the axially-aligned blowing nozzle, reducing the net torque transmitted to the user's hand while maintaining adequate blowing performance
3Productivity
If the blower operates at full power to maximize work output, then productivity is improved, but the reaction torque varies dynamically causing increased user fatigue
Solution Approach 1:
The angled suction nozzle configuration creates a counter-torque that acts as a mechanical counterweight to the torque generated by the blowing nozzle. This counter-torque mechanism continuously opposes the reaction torque from the exhaust airflow, reducing the net torque variation experienced by the user's hand during dynamic operation across different power levels
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 blower effectively reduces the torsional torque on the user's hand, enhances comfort, and minimizes noise by optimizing the air flow's directional component and velocity distribution, allowing for more efficient operation with reduced user fatigue.
Implementation Method 1
a network of directional channels for homogenizing an intake airflow, the network of directional channels being provided in the vicinity of the intake mouth - the network of directional channels has a network axis, and the network axis has an intersection point with the second plane, the intersection point being located upstream of the first plane - the network of directional channels is configured to give the intake airflow a directional component opposite to the fan
Data Source
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AI summary
The invention relates to a portable blower (10) comprising: - an axial fan blower (18), - a handle (12) that has a midpoint of equilibrium (E), - a blowing outlet that is connected downstream of the axial fan, - at least one suction nozzle (32) that is connected upstream of the axial fan and has an air intake mouth (34). According to the invention, the air intake nozzle comprises a network (42) of directional channels (44) for homogenizing a flow of intake air, the network of directional channels being formed in the vicinity of the air intake mouth (34). The invention finds applications notably in the field of portable electric blowers for the maintenance of public spaces.