External Pressure Sensor Mounting for Dialysis Accuracy
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Solution Overview
Problem
Existing pressure measurement systems in extracorporeal blood treatment machines, such as dialysis machines, face inaccuracies and complexities due to unstable sensor positions, susceptibility to damage, and incorrect connections, leading to potential patient and staff safety risks, as well as increased costs and assembly challenges.
Innovation Solution
A pressure measurement arrangement featuring a machine-external, adjustable holder with a rigid fluid line connecting the pressure sensor to the line system, eliminating the need for additional hoses and allowing for precise, stable positioning of the sensor, reducing the risk of incorrect connections and environmental damage, while maintaining measurement accuracy and response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin tube is used to connect the pressure sensor to the pressure sensor port, then the sensor can be positioned inside the housing, but the thin tube is susceptible to damage such as kinking and creates a large dead volume that limits measurement accuracy and response time
Solution Approach 1:
The pressure sensor is extracted from the housing interior and mounted externally on the housing surface. This eliminates the need for internal thin tubing connections, removing the source of kinking damage and reducing dead volume to minimal, thereby improving both connection reliability and measurement precision simultaneously
Solution Approach 2:
A rigid but plastically bendable rod serves as an intermediary mounting structure between the external pressure sensor and the housing. This rod provides a stable, damage-resistant connection path that eliminates the problematic thin tube while maintaining sensor positioning capability
2Adaptability or versatility
If additional internal tubing is used to connect the housing pressure sensor port to the pressure sensor, then the sensor can be positioned inside the housing, but numerous transitions or connection points are necessary which increases the risk of leaks and leads to complex and expensive installation
Solution Approach 1:
The pressure sensor is extracted from the housing interior and mounted externally, eliminating the need for complex internal tubing systems with multiple transitions and connection points. This single external mounting point dramatically reduces system complexity and leak risk while maintaining positioning flexibility through the bendable rod
Solution Approach 2:
The mounting rod integrates multiple functions: it serves as the structural support, the positioning mechanism, and the protective enclosure for the electrical conductor all in one component. This merging eliminates the need for separate tubing, mounting brackets, and cable management systems
3Ease of operation
If the pressure sensor hangs in the tubing of the piping system, then the sensor can be positioned in the flow path, but the sensor floats in undefined, unstable positions causing measurement inaccuracies
Solution Approach 1:
The pressure sensor is extracted from the floating position within the tubing and relocated to a fixed external mounting position on the housing. The bendable rod provides stable positional definition while maintaining ease of installation through simple external attachment
Solution Approach 2:
The mounting rod is designed to be rigid for stable sensor positioning but plastically bendable during installation to accommodate different sensor positions and orientations. This dynamic property allows easy adjustment during setup while maintaining stability during operation
4Ease of operation
If standardized interfaces such as Luer-lock connectors are used for connecting the hose to the pressure sensor port, then the connection can be made easily, but it is easy for a user to accidentally connect the hose to the wrong port leading to interruptions or delays in therapy
Solution Approach 1:
The pressure sensor connection is extracted from the standardized Luer-lock interface and replaced with a custom integrated coupling. This custom interface eliminates compatibility with wrong ports while maintaining ease of connection through dedicated matching geometries
Solution Approach 2:
The coupling section has specialized local geometry with specific male/female matching features designed exclusively for this pressure sensor port. This localized customization ensures that only the correct sensor can be connected to this specific port, preventing mismatched connections while keeping the connection process simple
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
This solution ensures accurate and reliable pressure measurement, reduces the risk of errors and leaks, simplifies assembly, and protects the electrical connection from environmental influences, enhancing the safety and efficiency of dialysis therapy.
Implementation Method 1
a pressure sensor (7) that can be connected to a pressure sensor (9) connected or connectable to the line system (11) via a rigid, flexurally stiff fluid line (10) and that converts a fluid pressure signal from the rigid, flexurally stiff fluid line (10) into an electrical signal
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a pressure-measuring assembly for measuring the internal line pressure of a line system of an extracorporeal blood treatment machine, comprising: - a pressure sensor (7), which can be connected, by means of a rigid, flexurally stiff fluid line (10), to a pressure receiver (9) connected or connectable to the line system and which converts a fluid pressure signal from the rigid, flexurally stiff fluid line (10) into an electrical signal; - an electrical line, which is used to connect the pressure sensor (7) to electronics in order to process the electrical signal; and - a retainer (5) for directly or indirectly retaining the pressure sensor (7), the retainer (5) forming, at least in parts, an inner channel, in which the electrical line is led in a manner protected from the environment, or the retainer (5) being in the form of a substantially plastically curvable bar which has, at one axial end portion, a fastening device for mounting on a stationary base and, at the other axial end portion, an articulation point for the pressure sensor (7) or the pressure receiver (9).