Pressure Sensor Deformable Plane for Extracorporeal Circuits
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Solution Overview
Problem
Existing pressure sensors for extracorporeal circulating circuits face issues such as retention and coagulation of body fluids due to contact with air, variable pressure measurements, and the need for complex configurations with pumps and valves, leading to inaccuracies and increased costs.
Innovation Solution
A pressure sensor design featuring a liquid chamber with a deformable plane that is not deformed by pressure, a separate reference plane, and a baffle plate to enhance fluid exchange, along with an air chamber that maintains a constant volume, allowing for accurate pressure measurement without air contact and simplifying the configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drip chamber with air layer is used to measure pressure without direct contact with body fluid, then the body fluid is protected from air contact, but the large volume required causes fluid retention and coagulation
Solution Approach 1:
The patent introduces a deformable plane as an intermediary between the body fluid and the pressure sensing mechanism. This deformable plane transmits pressure information to the air chamber without requiring direct contact between body fluid and air, eliminating the need for large air layers that cause fluid retention. The deformable plane deforms in response to pressure changes and transmits this deformation to the air chamber, enabling accurate pressure measurement while minimizing fluid contact with air.
2Device complexity
If the liquid flow inlet and outlet are positioned in-line, then the sensor structure is simplified, but flow stagnation occurs causing coagulation
Solution Approach 1:
The patent positions the liquid flow outlet not in-line with the inlet, but at a location separated by more than one-half of the inner circumference in the flow direction. This spatial arrangement in a different dimensional configuration prevents flow stagnation by ensuring continuous fluid movement through the chamber, eliminating dead zones where coagulation could occur while maintaining structural simplicity.
3Measurement precision
If a deformable plane with corrugated shape is used, then pressure sensitivity is improved, but the air chamber volume must be increased causing flow stagnation
Solution Approach 1:
The patent employs a deformable plane made of flexible material that can deform in response to pressure changes. This flexible membrane transmits pressure information to the air chamber without requiring a large corrugated structure, thereby maintaining pressure sensitivity while minimizing the air chamber volume to prevent fluid retention and coagulation.
4Reliability
If the deformable plane closely contacts the wall surface under negative pressure, then the sealing is improved, but the liquid flow inlet or outlet may be blocked
Solution Approach 1:
The patent creates an asymmetric spatial relationship between the deformable plane and the liquid flow inlet/outlet positions. The outlet is strategically located more than one-half of the inner circumference away from the inlet, ensuring that even when the deformable plane contacts the wall surface under negative pressure, the flow path remains open and unblocked, maintaining both sealing integrity and flow continuity.
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 solution effectively prevents fluid retention and coagulation, reduces measurement errors, and simplifies the sensor configuration, enabling safe and accurate pressure measurement in extracorporeal circulation therapies.
Implementation Method 1
a deformable plane 20 which is at least partially deformed by a pressure in the liquid chamber 6
Implementation Method 2
the liquid which is introduced into the liquid chamber 6 flows along an inner circumference of side surfaces of the first connecting plane 11
Data Source
Figure 1(A)~2(B)
Figure 3(A)~4(B)
Figure 5~6
AI summary
A pressure sensor (1) for an extracorporeal circulating circuit comprising a liquid chamber (6), a pressure measuring means (7), and a liquid flow path (8); wherein the liquid chamber (6) comprises a reference surface (10) not deformed by a pressure in the extracorporeal circulating circuit, a deforming surface (20) disposed separated from the reference surface (10) and deformed at least partially by a pressure in the extracorporeal circulating circuit, a first connection surface (11) that joins the deforming surface (20) with the reference surface (10) to form a closed liquid-tight space inside them and is not deformed by a pressure in the extracorporeal circulating circuit, a liquid inflowing port (40) provided in the side surface of the first connection surface (11), and a liquid outflowing port (41) disposed away by 1/2 to less than one round from the inflowing port (40) in the flowing direction of liquid introduced along the inner periphery of the side surface of the first connection surface (11); the pressure measuring means (7) measures the deformation amount of the deforming surface (20), and is disposed outside the liquid chamber (6); and the liquid flow path (8) is liquid-tightly connected with the liquid inflowing port (40) so that liquid to be introduced into the liquid chamber (6) flows in along the inner periphery of the side surface of the first connection surface (11).