Load Bank Airflow Sensor Using Reed Switch Flutter Isolation
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Solution Overview
Problem
Existing load banks with convective heat dissipation suffer from high-frequency fluttering or vibration of wind vane paddles due to turbulent airflow, leading to rapid wear and tear of mechanical switches and unreliable airflow monitoring.
Innovation Solution
Employing a wind vane sensor with a reed switch and a magnetically actuated mechanism, where the reed switch transitions to a stable state at an intermediate position, allowing the paddle to flutter without changing states, reducing mechanical stress and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical push button switch is used with a wind vane paddle, then the switching state can indicate airflow velocity, but the high-frequency fluttering causes rapid wear and tear of the mechanical switch
Solution Approach 1:
The patent replaces the mechanical push button switch with a reed switch that is actuated by a magnetic field from a magnet on the wind vane paddle. This substitution eliminates mechanical contact wear while maintaining the switching function. The reed switch responds to the magnetic field changes as the paddle moves, providing reliable airflow monitoring without the wear problems of mechanical contacts.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the wind vane paddle motion and the switching action. Instead of direct mechanical contact, the magnet on the paddle interacts with the reed switch through the magnetic field, allowing the switching function to be performed without mechanical wear. This intermediary mechanism resolves the contradiction between reliable monitoring and switch durability.
2Measurement precision
If the wind vane paddle is positioned to detect turbulent airflow, then airflow monitoring is achieved, but the paddle experiences high-frequency vibration between positions
Solution Approach 1:
The patent utilizes the periodic nature of the paddle's fluttering motion by positioning the reed switch to respond to the magnetic field at specific points in the oscillation cycle. The reed switch is triggered when the magnet passes within a certain distance during the paddle's vibration, converting the unstable periodic motion into a useful periodic switching signal that indicates airflow presence without requiring stable paddle positioning.
Solution Approach 2:
The patent changes the detection parameter from requiring a stable paddle position to detecting the magnetic field strength variations caused by paddle vibration. By monitoring the magnetic field parameter rather than the paddle's absolute position, the system can accurately detect airflow conditions even when the paddle is constantly vibrating between positions.
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 reduces switch wear and enhances airflow monitoring reliability by preventing high-frequency switching, thereby increasing durability and safety.
Implementation Method 1
a reed switch arranged on the housing (or on the wind vane paddle) and actuated by a magnetic field, and a corresponding magnet arranged on the wind vane paddle (or on the housing) that generates the magnetic field
Implementation Method 2
load banks as high-power resistors in which electrical energy is converted into heat
Implementation Method 3
This heat is then dissipated by forced convection via a fan
Data Source
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AI summary
The present invention relates to a load bank (1) for converting electrical energy into thermal energy, comprising a waste heat chamber (10), a fan (14) arranged in the waste heat chamber (10) which is capable of generating an airflow, at least one heating element (13) arranged in the waste heat chamber (10) which can be exposed to the airflow while emitting thermal energy, and an airflow sensor (16) arranged in the waste heat chamber (10) and exposed to the airflow, configured as a wind vane sensor. The airflow sensor comprises a housing (18), a wind vane paddle (20) movably mounted on the housing (18), a reed switch arranged on the housing (18) which can be actuated by a magnetic field, and a corresponding magnet arranged on the wind vane paddle (20) which generates the magnetic field.The wind vane paddle (20) can be brought into a starting position by a restoring force and, with a sufficiently strong airflow, can be brought via an intermediate position to a final position, wherein the distance between the reed switch and the corresponding magnet in the intermediate position differs from the corresponding distance in the starting position such that the reed switch has a first switching state in the starting position and a second switching state in the intermediate position.