Dialysis Pressure Sensor With Diaphragm Interface for Fluid Isolation
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Solution Overview
Problem
Existing pressure measurement technologies in disposable sets for dialysis systems face challenges such as contamination risk, inaccuracy, complexity, and high cost due to direct contact with fluids, sensitivity to membrane variations, and inability to measure both positive and negative pressures accurately.
Innovation Solution
A pressure sensor system using a diaphragm and indenter with a convex surface to indirectly measure fluid pressure, allowing for accurate and reusable measurements without direct contact, capable of measuring both positive and negative pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct contact pressure sensors are used in disposable sets, then pressure measurement is simple, but contamination risk increases and measurement accuracy decreases due to fluid exposure
Solution Approach 1:
The patent introduces a diaphragm as an intermediary element that transmits pressure from the fluid to the sensor without direct contact. The diaphragm is positioned at the distal end of the fluid line, allowing pressure measurements while maintaining fluid isolation and preventing contamination of the sensor.
Solution Approach 2:
The sensor is extracted from direct contact with the fluid environment and positioned at a remote location. The pressure measurement function is separated from the fluid path, allowing the sensor to remain outside the disposable set while still measuring fluid pressure through the diaphragm interface.
2Measurement precision
If disposable sets include integrated pressure sensors, then measurement is direct, but device complexity and cost increase
Solution Approach 1:
The pressure sensor is extracted from the disposable set and positioned in the reusable pump system. Only the simple diaphragm interface remains in the disposable set, while the complex sensor electronics are located externally, reducing disposable set complexity and cost.
Solution Approach 2:
The pump system serves multiple functions: it provides fluid pumping capability and houses the pressure sensor for monitoring. This multi-functionality eliminates the need for separate integrated sensors in each disposable set, reducing overall system complexity.
3Object-affected harmful factors
If membrane-based pressure sensors are used, then fluid isolation is achieved, but sensitivity to membrane variations reduces measurement accuracy
Solution Approach 1:
The diaphragm serves as a standardized intermediary with controlled physical properties. By carefully selecting and characterizing the diaphragm material and geometry, the system achieves fluid isolation while minimizing the impact of membrane variations on measurement accuracy through calibration procedures.
Solution Approach 2:
The system compensates for membrane variations by introducing calibration parameters and adjustment mechanisms. The sensor can be calibrated against known pressure references, allowing the system to account for diaphragm thickness and material property variations, thereby maintaining measurement precision despite membrane variability.
4Loss of substance
If reusable pump systems are used with disposable sets, then cost is reduced, but pressure measurement capability is lost
Solution Approach 1:
The diaphragm acts as a universal interface that connects the disposable set to the reusable pump system's pressure sensor. This intermediary allows the reusable pump to maintain pressure measurement capability while working with disposable sets, enabling waste reduction without sacrificing measurement functionality.
Solution Approach 2:
The reusable pump system is designed with universal pressure measurement capability that works with all disposable sets through the standardized diaphragm interface. This multi-functionality allows a single reusable pump to serve multiple patients and treatments while maintaining accurate pressure monitoring, reducing waste without losing measurement capability.
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 system provides accurate, reusable, and cost-effective pressure measurements within safe operating ranges, reducing contamination risk and waste while ensuring patient safety by isolating fluids and minimizing discomfort.
Implementation Method 1
the load cell is configured to measure a force applied to the indenter by the diaphragm and/or by the fluid within the cavity
Implementation Method 2
the indenter is movable along an axis such that, when the diaphragm is aligned with the axis, the convex contacting surface of the indenter can be brought into contact with the outer surface of the diaphragm and deform the diaphragm inward toward the cavity
Data Source
AI summary
Pressure sensors, including pressure sensors for automated peritoneal dialysis (APD) systems, and associated systems, devices, and methods are disclosed herein. In one embodiment, an APD system includes a diaphragm positioned over an opening in a disposable set that includes one or more fluid lines. The diaphragm is affixed to the disposable set about a periphery of the opening. The APD system further includes a pressure sensor configured to measure a pressure of fluid flowing through the disposable set. The pressure sensor includes a load cell and an indenter. The indenter can be moveable along an axis such that, when the diaphragm is aligned with the axis, a convexly curved surface of the indenter can be positioned against the diaphragm. When the indenter is contacting the diaphragm, the load cell can measure a force applied to the load cell by the diaphragm and/or by the fluid flowing through the disposable set.