Fan Impeller with Resilient Leading Edge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ventilation fans face noise and efficiency issues due to turbulence caused by grills or plates used for safety, which obstruct airflow and increase noise levels.
Innovation Solution
An impeller design featuring a hub and blades with a resilient material along the leading edge, connected via a resilient hub portion, allowing for bi-injection moulding and eliminating the need for additional protective grills, ensuring safety and smooth airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grill or plate is provided between the impeller and the room for safety, then user safety is improved, but noise levels increase and airflow efficiency deteriorates
Solution Approach 1:
The impeller blades have different material properties at different locations: the leading edge is made of soft resilient material for safety, while the rest of the blade maintains rigid material for efficient air movement. This local differentiation allows the fan to operate safely without requiring an external grill, thus avoiding noise and airflow obstruction.
Solution Approach 2:
The soft resilient material on the leading edge, which might seem to increase resistance, actually reduces turbulence and noise by smoothly interacting with air flow and preventing violent collisions. The safety feature itself becomes beneficial by reducing harmful turbulence effects.
2Reliability
If a grill or plate is provided for safety, then user safety is improved, but airflow efficiency deteriorates due to turbulence and drag
Solution Approach 1:
The impeller blades have different material properties at different locations: the leading edge is made of soft resilient material for safety, while the rest of the blade maintains rigid material for efficient air movement. This local differentiation allows the fan to operate safely without requiring an external grill, thus avoiding noise and airflow obstruction.
Solution Approach 2:
The soft resilient material on the leading edge, which might seem to increase resistance, actually reduces turbulence and noise by smoothly interacting with air flow and preventing violent collisions. The safety feature itself becomes beneficial by reducing harmful turbulence effects.
3Productivity
If the impeller is exposed without additional protection, then airflow efficiency is improved, but user safety deteriorates
Solution Approach 1:
The impeller blades have different material properties at different locations: the leading edge is made of soft resilient material for safety, while the rest of the blade maintains rigid material for efficient air movement. This local differentiation allows the fan to operate safely without requiring an external grill, thus avoiding noise and airflow obstruction.
Solution Approach 2:
The impeller itself provides the safety function through its soft resilient leading edge, eliminating the need for separate protective devices. The safety feature is integrated into the impeller design, allowing it to protect users while maintaining airflow efficiency.
4Reliability
If separate safety components are added to the impeller, then user safety is improved, but device complexity increases
Solution Approach 1:
The safety function is merged with the impeller blade structure itself. The soft resilient material is integrated into the leading edge of the blades, combining the air-moving function and the safety function into a single component, thus avoiding additional protective devices and reducing overall system complexity.
Solution Approach 2:
The impeller blade serves multiple functions: it moves air efficiently (rigid material portion) and provides safety protection (soft resilient leading edge). This multi-functionality eliminates the need for separate safety components, reducing device complexity while maintaining both performance and safety.
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 solution provides a quieter and more efficient operation by dissipating impact energy and maintaining impeller balance, reducing noise and enhancing airflow efficiency without additional protective barriers.
Implementation Method 1
The resilient material formed on the leading edge of the blades is softer than the rigid material which forms the main body of the impeller (hub and blades). Consequently, in an impact between the leading edge of the blades and another object, the energy is dissipated in the resilient material, reducing the force on the object
Implementation Method 2
The impeller can be moulded by bi-injection moulding. Bi-injection moulding provides a particularly good bond between the two materials. The injection point can be placed centrally, over the axis of rotation of the impeller in the centre of the hub. The pressure of inserting the molten resilient material is then symmetrically distributed around the impeller which results in even formation of the resilient material and maintains the balance of the impeller
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An impeller for a fan, comprising a hub and a plurality of blades extending from the hub, wherein each blade has a leading edge and a trailing edge and wherein each blade has a first portion made from a rigid material and a second portion formed on the leading edge of the first portion and formed from a resilient material. The impeller increases the safety of the impeller by reducing the potential damage or injury caused by collision with the impeller. Consequently, a fan with such an impeller does not require a protective grill in order to meet safety regulations. The absence of a grill increases the efficiency of the fan and reduces the noise caused by turbulence as air passes through the grill. A method of making the impeller is also provided.