Capacitive Pressure Sensor Segmentation for Disposable Medical Use
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Solution Overview
Problem
Current pressure and flow sensors are expensive and not suitable for disposable use, especially in medical and pharmaceutical applications, due to their high cost and the need for cleaning and re-use, and they are not effective for non-contact measurements at low flow rates and pressures.
Innovation Solution
A pressure sensor with a deformable measurement chamber made of elastic material, where the shape of the chamber varies with fluid pressure, influencing the electrical field and capacitance between fixed measurement electrodes, allowing for a capacitive measurement that detects changes in fluid pressure without contaminating the reusable electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If state of the art pressure sensors are used, then measurement precision is achieved, but cost and complexity increase making disposable use prohibitive
Solution Approach 1:
The sensor is divided into two separate parts: a disposable measurement chamber that contacts the fluid and a reusable sensor body containing the electrodes and electronics. This segmentation allows the complex sensor components to be separated from the disposable part, reducing the complexity of the disposable component while maintaining measurement precision through the reusable sensor body.
Solution Approach 2:
The measurement chamber acts as an intermediary element between the fluid and the sensor electrodes. It transmits pressure information to the electrodes without requiring direct contact between the fluid and the sensitive electronic components, enabling simple disposable construction while preserving measurement capability.
2Object-affected harmful factors
If sensors are made disposable for medical applications, then contamination is prevented, but cost increases
Solution Approach 1:
By segmenting the sensor into disposable and reusable parts, only the measurement chamber needs to be discarded after single use, preventing contamination of the fluid path. The expensive sensor body with electrodes can be sterilized and reused multiple times, significantly reducing the cost per disposable sensor compared to making the entire sensor disposable.
Solution Approach 2:
The measurement chamber is designed as a cheap, disposable component that can be easily manufactured and discarded after single use. This allows the system to achieve the benefits of disposable sensors (contamination prevention) without the prohibitive cost of making entire complex sensors disposable.
3Ease of operation
If piezoresistive or thermal transduction principles are used, then sensor functionality is achieved, but non-contact measurement capability is lost
Solution Approach 1:
The patent replaces direct mechanical contact measurement (piezoresistive) or thermal contact measurement with capacitive coupling through the measurement chamber wall. The electrodes measure pressure changes non-contactly by detecting capacitance variations caused by pressure-induced deformations of the measurement chamber, enabling non-contact measurement while maintaining reliability through the well-established capacitive sensing principle.
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 low-cost, disposable pressure sensing with high sensitivity and precision, preventing contamination of reusable parts and allowing for accurate measurement of fluid pressure and flow rates, suitable for various industrial and medical applications.
Implementation Method 1
the at least two measurement electrodes form a capacitor, wherein an influence of a variation of the shape of the measurement chamber on the electrical field can be detected as a change in the capacity of the capacitor
Implementation Method 2
the measurement chamber is arranged relative to the measurement electrodes to be arranged within a region of an electrical field originating from the measurement electrodes upon application of a potential to the measurement electrodes
Implementation Method 3
A pressure sensor with a deformable measurement chamber made of elastic material, where the shape of the chamber varies with fluid pressure
Data Source
AI summary
A pressure sensor (110) for measuring a fluid pressure of a fluid (112) within a measurement chamber (114) comprises the measurement chamber (114) having a mechanical deformable wall (116), a shape of the measurement chamber (114) varying depending on a pressure within the measurement chamber (114). The pressure sensor further comprises a measurement electrode (118), wherein the measurement chamber (114) is arranged relative to the measurement electrode (118) to be arranged within a region of an electrical field (120) originating from the measurement electrode (118) upon application of a potential to the measurement electrode (118), wherein an influence of a variation of the shape of the measurement chamber (114) on the electrical field (120) can be detected.