Air Filter Pollution Monitoring Using Corrected Resistance
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Solution Overview
Problem
Existing air filter monitoring systems in vacuum cleaners fail to accurately detect filter pollution due to flow variations and power setting changes, leading to incorrect signaling of filter cleanliness.
Innovation Solution
A method using a combination of pressure difference over the fan and motor current to predict air flow and calculate filter resistance, which is then used to determine filter pollution levels, employing a microprocessor to generate feedback on filter status and control functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure difference over the filter is used to detect filter pollution, then filter pollution can be detected, but the detection accuracy deteriorates due to flow variations and power setting changes
Solution Approach 1:
The patent introduces an intermediary calculation step that combines pressure difference measurements with flow rate information to derive a corrected filter resistance value. This intermediary parameter compensates for the effects of flow variations and power setting changes, allowing accurate filter pollution detection regardless of operating conditions.
Solution Approach 2:
The patent changes the parameter being measured from raw pressure difference to corrected filter resistance, which is derived by combining pressure difference with flow rate data. This parameter transformation eliminates the dependency on operating conditions, making the detection accurate across varying flows and power settings.
2Ease of operation
If pressure switch is used to measure pressure difference over filter, then filter pollution can be indicated, but false signals occur when flow changes due to speed regulator settings or surface type
Solution Approach 1:
The patent implements a feedback mechanism where flow rate information is continuously obtained and used to adjust the interpretation of pressure difference measurements. This feedback loop ensures that the filter pollution indication remains accurate even when flow conditions change due to speed regulator adjustments or different cleaning surfaces.
3Productivity
If flow rate is increased to improve cleaning performance, then cleaning efficiency improves, but filter pollution detection becomes inaccurate due to higher pressure differences
Solution Approach 1:
The patent transforms the measurement parameter from raw pressure difference to corrected filter resistance by incorporating flow rate data. This allows the system to maintain accurate filter pollution detection across the full range of flow rates, enabling users to operate at high cleaning efficiency without compromising detection accuracy.
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 provides a reliable and accurate assessment of filter pollution, independent of power settings, ensuring correct identification of filter cleanliness and optimal operation of the vacuum cleaner.
Implementation Method 1
measuring a pressure difference over the fan, and the motor current has shown to deliver a reliable flow prediction
Implementation Method 2
a combination of measuring a pressure difference over the fan, and the motor current has shown to deliver a reliable flow prediction
Data Source
Figure 1~2
AI summary
In a method of monitoring pollution of an air filter (Filt1) in a device in which an air flow (A) generated by a fan (F) engaged by a motor (M) passes the air filter (Filt1), the pollution is determined using data representative of a pressure difference (D2) over the fan (F), a pressure difference (D1) over the air filter, and a motor current (I) to the motor (M).The method comprises the steps of: estimating a flow through the air filter from data representative of the pressure difference (D2) over the fan (F), and the motor current (I) to the motor (M), estimating a filter resistance of the air filter from data representative of the flow through the air filter, and the pressure difference (D1) over the air filter, and estimating the pollution of the air filter from data representative of the filter resistance of the air filter.