Halogenated gas sensor
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Solution Overview
Problem
Existing halogenated gas sensors, such as Tin oxide based MOS sensors and NDIR sensors, suffer from cross-sensitivity to hydrocarbons and humidity, and solid state bead type sensors lack reproducible performance due to undefined phase ratios and low operating temperatures, making them ineffective for detecting HFOs and HFCs with high sensitivity.
Innovation Solution
A bead-type sensor using NaAlSiO4 and KAlSiO4 as sensing materials, embedded in a platinum coil and center electrode, operating at high temperatures (400°C-1000°C) with a current or voltage applied to heat the coil, and a method of manufacturing these materials through ion exchange and heat treatment to achieve high sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Tin oxide based MOS sensors are used for halogenated gas detection, then the sensor can detect halogenated gases, but the sensor shows cross sensitivity to many hydrocarbons and humidity
Solution Approach 1:
The patent applies local quality by using a specific ceramic composition (potassium silicate and aluminum oxide in defined ratios) that creates a sensing material with tailored properties for selective halogenated gas detection. The defined phase ratios and controlled particle sizes (0.25-4.0 parts potassium silicate to 1 part aluminum oxide) create localized chemical environments that respond specifically to halogenated gases while ignoring hydrocarbons and humidity.
2Measurement precision
If NDIR optical sensors are used for halogenated gas detection, then the sensor can detect halogenated gases, but the sensor is expensive to produce and shows limited sensitivity
Solution Approach 1:
The patent employs a cost-effective ceramic-based sensing material (potassium silicate and aluminum oxide mixture) that can be manufactured through simple mixing and heating processes. This solid-state bead sensor replaces expensive NDIR optical systems with a disposable or replaceable ceramic bead that achieves comparable or superior sensitivity for HFO and HFC detection, significantly reducing production costs.
3Ease of manufacture
If solid state bead type sensors with low operating temperature (500-600°C) are used, then the sensor is cheaper to produce, but the sensor cannot detect HFOs and HFCs with decent sensitivity
Solution Approach 1:
The patent changes the operating temperature parameter from the conventional 500-600°C range to a higher range of 800-1000°C. This parameter change is enabled by using a ceramic material with high thermal stability (potassium silicate and aluminum oxide) that can withstand elevated temperatures. The higher operating temperature enhances the sensor's sensitivity to HFOs and HFCs while maintaining cost-effectiveness through simple manufacturing processes.
4Ease of manufacture
If a broad ratio mixture of potassium silicate and aluminum oxide is used, then the sensor can be manufactured easily, but reproducible sensor performance is not easy to achieve
Solution Approach 1:
The patent segments the sensing material into distinct phases with defined ratios of potassium silicate and aluminum oxide (0.25-4.0 parts to 1 part). This segmentation approach allows for controlled mixing and heating processes that produce reproducible ceramic beads. The defined phase ratios create consistent sensing properties across different manufacturing batches, achieving both manufacturing flexibility and performance reproducibility.
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 sensor achieves selective and sensitive detection of HFOs and HFCs, with high melting points allowing operation up to 1000°C, and can detect refrigerant leaks with high sensitivity and specificity, particularly for R134a and R1234yf, while ignoring other gases like isobutene, hydrogen, and methane.
Implementation Method 1
The coil is heated by current passing through it
Implementation Method 2
The conductance between center electrode and heated coil changes with concentration of halogenated gas
Data Source
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AI summary
Halogenated gas sensor for detecting halogenated gas, comprising at least a first metal electrode and a second metal electrode, which are connected with a sensing material, which comprises at least one of NaAlSiO4, KAlSiO4, RbAlSiO4, CsAlSiO4.