Flame Detection Signal Modulation for Intrinsically Safe Self-Testing
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Solution Overview
Problem
Existing flame detection devices face challenges in easily testing for false positive detections without requiring additional transmitting elements and ensuring intrinsic safety, particularly when using photodiodes that generate photocurrents without external operating voltages.
Innovation Solution
A flame detection device utilizing an optoelectronic sensor unit and a modulator unit to modulate the flame detection signal onto a carrier signal, combined with an active bandpass filter to verify the functionality of the amplifier and evaluation circuit, ensuring false positive detections are recognized and discarded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intrinsically safe photodiode sensor unit is used to generate photocurrent without external voltage, then intrinsic safety against false negatives is improved, but the ability to test for false positive detections deteriorates
Solution Approach 1:
A test signal generator is introduced as an intermediary component that generates test signals to simulate flame detection signals. This allows the evaluation circuit to be tested for false positive detections without requiring external optical or electromagnetic control signals, thus maintaining intrinsic safety while enabling comprehensive testing capability.
Solution Approach 2:
The flame detection device performs self-testing through the test signal generator and evaluation circuit combination. The device can autonomously verify its own functionality by generating test signals and evaluating them through the same detection path used for actual flame detection, eliminating the need for separate testing equipment or additional transmitting elements.
2Ease of operation
If additional transmitting elements are added to enable testing of the amplifier and evaluation circuit, then testing capability is improved, but device complexity and intrinsic safety deteriorate
Solution Approach 1:
The test signal generator is integrated into the existing flame detection device architecture, merging the testing function with the detection system. This consolidation allows testing capability to be added without requiring separate external transmitting elements, thus avoiding increased device complexity while maintaining intrinsic safety.
3Ease of operation
If additional transmitting elements are added to enable testing, then testing capability is improved, but intrinsic safety deteriorates
Solution Approach 1:
The test signal generator serves as an internal intermediary that creates test signals without requiring external transmitting elements. This approach maintains intrinsic safety by eliminating the need for additional optical or electromagnetic transmitting components while still enabling comprehensive testing of the amplifier and evaluation circuit through simulated flame detection signals.
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 provides an intrinsically safe flame detection device that prevents false positive detections by verifying the functionality of the amplifier and evaluation circuit, enhancing reliability and safety.
Implementation Method 1
The sensor unit is designed as an intrinsically safe sensor unit, preferably as a photodiode, which generates a photocurrent from the incident electromagnetic radiation energy without an external operating voltage
Implementation Method 2
a modulator unit having a first and a second input, wherein the sensor unit is connected to the first input of the modulator unit, and a carrier signal unit is connected to the second input of the modulator unit, and an output signal of the modulator unit is a modulation product of a flame detection signal of the sensor unit and a carrier signal of the carrier signal unit
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a flame detection device and a method for operating a flame detection device, comprising an optoelectronic sensor unit (1) suitable for flame detection and a modulator unit (2) having a first and a second input (2.1, 2.2), wherein the sensor unit (1) is connected to the first input (2.1) of the modulator unit (2) and a carrier signal unit (3) is connected to the second input (2.2) of the modulator unit (2) and an output signal of the modulator unit (2) is a modulation product of a flame detection signal of the sensor unit (1) and a carrier signal of the carrier signal unit (3).