Chemically-Stable Sensor With Fluoropolymer Membrane
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Solution Overview
Problem
Conventional optical sensors lack sufficient protection for their indicators against destructive influences in chemically aggressive environments, leading to limited service life and incompatibility with sterilization processes, particularly in applications like wastewater analysis and medical settings where heat-sterilization is required.
Innovation Solution
A sensory unit with a housing made of materials like stainless steel alloys, incorporating a protector element between the sensor element and the medium to prevent direct contact, and using a fluoropolymer membrane as the protector element to maintain chemical stability and prevent oxidative inactivation, while ensuring gas permeability for analytes like oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor element is directly exposed to the medium for analyte detection, then the measurement sensitivity is improved, but the service life is reduced due to chemical attack by reactive compounds
Solution Approach 1:
A protector element is introduced as an intermediary component between the sensor element and the medium. This protector element selectively permits analyte molecules to pass through while blocking reactive compounds that would damage the sensor. The protector element acts as a mediator that enables continuous operation by preventing direct contact between harmful substances and the sensor indicators.
2Ease of manufacture
If the sensor element uses a polymeric matrix for indicator immobilization, then the ease of manufacture is improved, but the chemical stability deteriorates when exposed to strong oxidizing agents
Solution Approach 1:
The sensor element utilizes a polymeric matrix in the form of a thin film or membrane for indicator immobilization. This flexible polymeric structure provides ease of manufacture while the added protector element compensates for the chemical instability, allowing the polymeric matrix to be used without sacrificing chemical resistance.
3Productivity
If the sensor is subjected to heat sterilization for reuse in sterile environments, then the productivity is improved through reusability, but the reliability deteriorates due to damage to sensor components
Solution Approach 1:
The protector element serves as a sacrificial protective layer that shields the sensor element during heat sterilization processes. By placing this protective barrier beforehand, the sensor can withstand repeated sterilization cycles without damage to its indicators or polymeric matrix, enabling reliable reuse in sterile environments.
4Duration of action of stationary object
If a protector element is added to protect the sensor element, then the service life is extended, but the device complexity increases
Solution Approach 1:
The protector element is implemented as a thin film or membrane structure that can be integrated into the existing sensor design. This film-based approach minimizes the increase in device complexity while providing effective protection, as the thin film adds minimal structural complexity compared to bulk protective components.
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 sensory unit provides extended service life and maintains accurate analyte detection even in aggressive chemical environments, with enhanced protection against reactive compounds and heat-sterilization, ensuring the integrity of sensor properties such as selectivity and response time.
Implementation Method 1
a protector element (4) which is arranged between the at least one sensor element (3) and the medium (M) to be analyzed, in particular between the indicator-bearing area or section and the medium (M), such that the sensor element (3) and in particular its indicator-bearing area or section cannot directly contact the medium (M)
Implementation Method 2
using a fluoropolymer membrane as the protector element to maintain chemical stability and prevent oxidative inactivation, while ensuring gas permeability for analytes like oxygen
Data Source
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AI summary
The invention relates to a sensing unit (1) comprising a housing (2) that has a first housing opening which can be oriented towards a medium (M) to be analyzed, and a second housing opening on which at least one means for detachably rigidly connecting to a sensor shaft or sensor housing are arranged, or may be arranged, on the inner and/or outer side; at least one sensor element (3) that is arranged in the housing (2) and comprises indicators and, optionally, indicator protectors, said sensor element (3) having a first side facing the first housing opening and a second side lying opposite the first housing opening; and at least one protector element (4) which is arranged in the region of the first housing opening between the at least one sensor element (3) and the medium (M) which surrounds the sensing unit (1), particularly in the region of said housing opening, such that the sensor element (3) does not come into direct contact with the medium (M).