Fan Arrangement with Adjustable Pitch for Power-Limited Airflow
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Solution Overview
Problem
Fan arrangements are often understressed and operate below their maximum permissible power level, limiting air output, especially under varying operating conditions, and can lead to overheating due to high power consumption at maximum rotation speed.
Innovation Solution
A controller compares electrical power consumption with a predetermined maximum motor power and adjusts pulse-width modulation signals to limit power consumption, ensuring the fan operates at its permissible power limit, allowing for increased air output without requiring a larger fan arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan is operated at maximum rotation speed to increase air output, then the volumetric flow rate is improved, but the power consumption exceeds the maximum permissible motor power and causes overheating
Solution Approach 1:
The patent applies dynamics by making the fan blade pitch angle adjustable during operation. The pitch angle is dynamically changed based on operating conditions to optimize the balance between air output and power consumption, allowing the fan to operate at or near maximum permissible power without exceeding thermal limits.
Solution Approach 2:
The patent changes the operational parameters of the fan by adjusting the pitch angle of the fan blades. This parameter change allows the fan to operate at its maximum permissible power level under varying conditions, optimizing air output while preventing overheating by maintaining power within safe limits.
2Productivity
If the fan is designed for free outlet operation to maximize air output, then the volumetric flow rate is improved, but the fan cannot operate efficiently at higher static pressures
Solution Approach 1:
The adjustable pitch angle mechanism allows the fan to adapt dynamically to different operating conditions. By changing the pitch angle, the fan can efficiently operate across a wide range of static pressures, from free outlet conditions to high pressure applications, thereby expanding its operating range while maintaining high air output.
Solution Approach 2:
The patent makes the fan arrangement universal by enabling it to perform multiple functions across different operating conditions. The adjustable pitch angle allows the same fan to efficiently handle both free outlet operations and high static pressure applications, eliminating the need for different fan designs for different applications.
3Reliability
If the fan is operated below maximum permissible power to prevent overheating, then reliability is improved, but the air output is limited
Solution Approach 1:
The patent employs feedback control by continuously monitoring operating conditions and adjusting the pitch angle accordingly. This feedback mechanism ensures the fan operates at or near maximum permissible power under varying conditions, maximizing air output while maintaining reliable operation within thermal limits.
Solution Approach 2:
The dynamic adjustment of pitch angle allows the fan to operate at maximum permissible power levels adaptively. This dynamic control prevents overheating by maintaining power within safe limits while simultaneously maximizing air output, resolving the contradiction between reliability and productivity.
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
This approach enables the fan to operate at its maximum permissible power, achieving greater volumetric flow rates at the same counterpressure, reducing the risk of overheating, and allowing for modification of air output through rotation speed control while maintaining efficient power usage.
Implementation Method 1
a limiting arrangement for adjusting pulse-width modulation signals if the power being consumed exceeds the maximum permissible motor power
Data Source
AI summary
A fan arrangement (20) has a fan (24) driven by an electric motor (22). It further has an apparatus for continuously detecting an actual electrical value associated with the electric motor (22) during operation, an input apparatus for inputting a desired electrical value for the operation of said electric motor,a comparison apparatus (26) for comparing said electrical value with the actual electrical value, and a controller which regulates said electrical value by pulse width modulation (36).