Air Sensor Calibration Using Purified Zero Air

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Solution Overview

Problem

Air sensors in air treatment devices often drift over time, leading to inconsistent measurements and inaccurate air quality indications, making it difficult for users to determine if indoor air quality has improved, and requiring inconvenient external zero air calibration.

Innovation Solution

An air treatment device generates clean air locally to calibrate its air sensor, using a processor to control the air flow and determine if the purified air meets predefined criteria, allowing for accurate calibration without external zero air generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external zero air is used to calibrate the air sensor, then the air sensor can be calibrated, but the user has to make efforts to find zero air which is inconvenient

Engineering Contradiction:
Improveair sensor calibration accuracyVSAvoidcalibration convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The air treatment device generates its own zero air through the air purifying unit for calibration purposes, eliminating the need for external zero air sources. The processor controls the air flow path to direct the generated zero air to the air sensor, enabling the device to calibrate itself autonomously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration function is merged with the air purification function. The air purifying unit that normally purifies ambient air is also used to generate zero air for calibration, and the air flow path is shared between normal operation and calibration modes through the switch mechanism.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If the air sensor is not calibrated regularly, then the device operation is simple, but the measurement output drifts over time leading to wrong air quality indications

Engineering Contradiction:
Improveoperation simplicityVSAvoidair quality measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration action by generating zero air and calibrating the air sensor at scheduled intervals or under specific conditions. The processor automatically manages the calibration process, including controlling the switch to direct zero air to the sensor and adjusting the sensor output accordingly, so users don't need to manually intervene.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms where the processor monitors the air sensor output and automatically initiates calibration when drift is detected or according to a schedule. The calibration process itself provides feedback by adjusting the sensor baseline based on the known zero air condition, ensuring continued measurement accuracy.

Inventive Principle:
Principle #23Feedback

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 method provides convenient and accurate calibration of air sensors, ensuring reliable air quality indications by using the device's own purified air to calibrate the sensor, improving user confidence and reducing calibration efforts.

Implementation Method 1

an air purifying unit configured to purify air

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2635902B1A method of calibrating an air sensor
Publication Date: 2018.12.12 PHILIPS INTPROP & STANDARDS GMBH
  • EP2635902B1 patent drawingFigure 1~3

AI summary

One embodiment of the invention provides an air treatment device. The air treatment device comprises: an air purifying unit, configured to purify air; an air sensor, configured to measure a first air quantity and provide a measurement output, wherein the first air quantity comprises the purified air purified by the air purifying unit; and a processor, configured to generate a first value based on the measurement output of the air sensor so as to calibrate the air sensor. With the air treatment device of one embodiment of the invention, clean air, i.e. zero air, is generated locally by the air treatment device so as to calibrate the air sensor, without the need for externally generating the zero air, which brings convenience for the user or other operators performing calibration of the air sensor of the air treatment device. Another embodiment of the invention also provides a method of calibrating an air sensor of an air treatment device. The method comprises the steps of: purifying air by using the air treatment device; and measuring a first air quantity by using the air sensor to get a first value so as to calibrate the air sensor, wherein the first air quantity comprises the purified air.