UV Flame Detector Window Layout to Reduce Ambient Light False Alarms

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Solution Overview

Problem

Current flame detection systems using UV sensors often produce false alarms due to ambient light and are costly to manufacture.

Innovation Solution

A compact UV flame detector design featuring UV transparent windows and UV sensing elements with partially transmissive materials, allowing for two-sided flame detection and reduced manufacturing costs through a vacuum process chamber with dual heating zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If UV sensors are used to detect flame, then flame detection capability is improved, but false alarms due to ambient light increase

Engineering Contradiction:
Improveflame detection capabilityVSAvoidfalse alarm rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by making only specific portions of the electrodes transmissive to UV radiation. The anode has a transmissive portion and the cathode has a transmissive portion positioned to face each other, while other areas remain opaque. This localized transmissivity allows UV photons to pass through to the photosensitive cathode only when aligned properly, enabling flame detection while blocking ambient light from other directions, thus resolving the contradiction between detection capability and false alarm rate.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If conventional manufacturing methods are used for flame detectors, then manufacturing precision is maintained, but manufacturing cost increases

Engineering Contradiction:
Improveassembly precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple manufacturing operations into a single vacuum process chamber. The spacer, anode, cathode, and UV-transparent window are all assembled and sealed together in one vacuum environment, eliminating the need for multiple separate manufacturing steps. This consolidation maintains manufacturing precision while significantly reducing manufacturing cost and complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a vacuum environment (inert atmosphere) for the entire assembly process. By performing all sealing and assembly operations in vacuum, the patent prevents contamination and ensures proper outgassing of the fill gas, maintaining high manufacturing precision while simplifying the overall manufacturing process through a single integrated vacuum chamber approach.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 effectively minimizes false alarms by enhancing discrimination against ambient light and reduces manufacturing costs by simplifying the assembly process and using cost-effective materials.

Implementation Method 1

The UV flame detector includes UV sensing elements comprising an anode and a cathode spaced apart from each other and arranged to define a gas space therebetween

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

The gas space within the spacer is filled with a gas composition arranged to enable a gas electron multiplier effect

Methodology Applied
Scientific EffectGas electron multiplier effect: Electron Avalanche

Data Source

PatentEP3887781B1Ultraviolet flame detector
Publication Date: 2025.02.19 CARRIER CORP
  • EP3887781B1 patent drawingFigure 1~2B
  • EP3887781B1 patent drawingFigure 3
  • EP3887781B1 patent drawingFigure 4A~4B

AI summary

A flame detector that includes a spacer, a UV transparent window, and a UV sensing elements. The spacer has a spacer wall that extends along a first axis between a first spacer end and a second spacer end. The UV transparent window is disposed at the first spacer end. The spacer wall and the UV transparent window define a gas space. The UV sensing elements is disposed within the gas space.