Moisture Sensor Element Using Vibrating Quartz and Porous Coatings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing moisture sensors for determining dew point in gases face challenges with high energy consumption, calibration difficulties, and susceptibility to drift, making them unsuitable for decentralized, mobile, or disposable applications.
Innovation Solution
A moisture sensor element with a vibrating element coated with defined-porous materials exhibiting non-linear mass changes in response to moisture, combined with a gas-permeable but water-impermeable membrane and optional heating or light irradiation, allows for reliable dew point determination with low energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal dew-level hygrometer or dew point hygrometer is used to measure moisture content, then measurement capability is achieved, but energy consumption is high due to temperature control requirements
Solution Approach 1:
The patent uses a vibrating element (quartz crystal or similar) coated with moisture-sensitive material to detect moisture content. The vibration frequency changes in response to mass changes from moisture absorption, enabling measurement without thermal control. This mechanical vibration-based approach eliminates the need for heating or cooling systems, dramatically reducing energy consumption while maintaining measurement precision.
Solution Approach 2:
The invention replaces the thermal field-based measurement system (heating/cooling to reach dew point) with a mechanical vibration-based system. The vibrating element detects moisture through mass-induced frequency shifts, substituting thermal energy requirements with mechanical oscillation, thereby achieving low-energy operation.
2Measurement precision
If coated quartz oscillators are used for dew point measurement, then measurement capability is achieved, but calibration difficulty and drift susceptibility increase
Solution Approach 1:
The patent employs porous coating materials on the vibrating element that exhibit defined, reproducible moisture absorption characteristics. The porous structure provides consistent capillary condensation behavior, leading to stable and repeatable frequency responses. This improves calibration stability and reduces drift compared to conventional coated oscillators, as the porous material's physical structure ensures consistent performance over time.
Solution Approach 2:
The invention utilizes controlled changes in the physical state of moisture within the porous material (adsorption, capillary condensation) to produce distinct, measurable frequency shifts. By operating in specific humidity ranges where these phase transitions occur, the sensor achieves stable, reproducible calibration points that minimize drift and improve reliability.
3Measurement precision
If standard QCM quartz platelets in pressure chamber are used, then dew point measurement is achieved, but device complexity increases due to temperature-controlled chamber requirement
Solution Approach 1:
The patent extracts and eliminates the temperature-controlled pressure chamber from the measurement system. By using a vibrating element that operates at ambient temperature and detects moisture through vibration frequency changes, the invention removes the complex thermal control infrastructure entirely, simplifying the device while maintaining measurement precision.
Solution Approach 2:
The vibrating element with porous coating can be designed as a simple, potentially disposable component that requires no complex infrastructure. This replaces the expensive, complex, and maintenance-intensive temperature-controlled chamber with a simple sensor that can be easily replaced if needed, significantly reducing device complexity.
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
Enables reliable dew point measurement with reduced energy usage and improved calibration stability, suitable for demanding environments and decentralized applications.
Implementation Method 1
at least one material, in particular a defined-porous material, on the vibrating element, wherein a mass of the at least one material changes rapidly in response to moisture changing over a moisture value range
Implementation Method 2
defined-porous materials exhibiting non-linear mass changes in response to moisture
Implementation Method 3
The piezoelectric crystal sensors comprise acoustic wave sensors such as thickness shear vibration (TSM) devices, acoustic surface wave (SAW) devices, acoustic plate mode (APM) devices and bent plate wave (FPW) devices and other arrangements of vibrating elements based on piezo crystals known to the expert
Implementation Method 4
an element for increasing the temperature of the vibrating element and the materials loaded thereon
Data Source
AI summary
In order to permit a robust, energy-efficient and precise moisture sensor, the invention relates to a moisture sensor element (10) for a moisture sensor (12) for measuring a moisture content in a gas, comprising at least one vibrating element (14) and at least one material (16, 18) on the vibrating element (14), wherein the at least one material (16, 18) is designed in such a way that the mass thereof changes rapidly with moisture changing over a moisture value. The invention also relates to a moisture-measuring method for measuring a moisture in a gas, comprising: using a moisture sensor element (10), wherein the course of the measurement signal thereof has at least one non-linearity according to the moisture; and determining a reference value based on the at least one non-linearity.