Smoke Detector Calibration Using Reference Signal Copying

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Solution Overview

Problem

Current methods for calibrating smoke detectors are time-consuming and prone to errors due to turbulence and inhomogeneities in aerosol distribution, making them difficult to integrate into mass production and ensuring uniform sensitivity across detectors.

Innovation Solution

An automatic adjustment method using a calibrated smoke detector as a reference detector, where the aerosol flow connects the housings of both detectors to ensure even aerosol exposure, allowing for data-driven calibration and iterative adjustments to match sensor signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If smoke detectors are calibrated in a smoke channel, then calibration can be performed, but the process becomes very time-consuming and difficult to integrate into mass production

Engineering Contradiction:
Improvecalibration accuracyVSAvoidproduction throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent uses a reference smoke detector that has already been calibrated to create a reference signal, which is then copied and used to calibrate multiple test smoke detectors. This eliminates the need for each detector to be individually calibrated in a time-consuming smoke channel, thereby increasing production throughput while maintaining calibration accuracy through the reference copy approach.

Inventive Principle:
Principle #26Copying

2Productivity

If a large number of smoke detectors are mounted on a carrier plate and tested together in the smoke channel, then throughput increases, but turbulence and inhomogeneities in aerosol distribution cause errors

Engineering Contradiction:
Improvecalibration throughputVSAvoidcalibration accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a reference smoke detector as an intermediary that experiences the turbulent and inhomogeneous aerosol conditions in the smoke channel, while test detectors are positioned in a test chamber with more controlled conditions. The reference detector's signal serves as a mediator to compensate for the differences, allowing accurate calibration of multiple detectors simultaneously without suffering from aerosol distribution errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a scattered light sensor is attached to a smoke channel to act as a reference, then aerosol can be conveyed into a sensor chamber, but the manner of calibration is not clearly described and integration into series production remains difficult

Engineering Contradiction:
Improvecalibration method flexibilityVSAvoidintegration into mass production
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements a self-calibration approach where the system automatically compares signals from reference and test smoke detectors and performs iterative adjustments without requiring manual intervention. The control unit autonomously processes the calibration data and adjusts test detectors based on reference detector signals, making the calibration process easily integrable into automated mass production lines.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If smoke detectors use inexpensive components with significant property differences, then cost is reduced, but sensitivity uniformity across detectors becomes problematic

Engineering Contradiction:
Improvecomponent costVSAvoidsensitivity uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs a feedback-based calibration method where each smoke detector's signal is compared against a reference detector's signal, and adjustment values are calculated and applied iteratively. This feedback loop compensates for component variations in inexpensive LEDs and other parts, ensuring uniform sensitivity across all detectors while maintaining low component costs.

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 approach simplifies the calibration process, reduces equipment requirements, and ensures consistent sensitivity across smoke detectors, enhancing production efficiency and accuracy.

Implementation Method 1

The at least one smoke alarm to be adjusted is placed in a channel subjected to a flowing aerosol

Methodology Applied
Scientific EffectAerosol flow: Convection

Implementation Method 2

A common method for calibrating smoke detectors is calibration in a so-called smoke channel

Methodology Applied
Scientific EffectLight scattering detection: Scattering

Data Source

PatentEP3392855B1Method and device for configuring a smoke detector
Publication Date: 2021.10.13 SIEMENS SCHWEIZ AG
  • EP3392855B1 patent drawingFigure 1~2
  • EP3392855B1 patent drawingFigure 3~4
  • EP3392855B1 patent drawingFigure 5

AI summary

The invention is a method and a device (10) operating according to the method for calibrating a smoke detector (12), wherein the calibration is carried out using a smoke detector that has already been calibrated and serves as a reference detector (20).