Balancing Device for Dialysis Pressure Compensation

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Solution Overview

Problem

Existing dialysis devices face challenges in achieving precise liquid balancing due to material volume inconsistencies and pressure changes, leading to incorrect balancing during dialysis treatments.

Innovation Solution

A balancing device with an exchange vessel and pressure sensor, controlled by a unit that adjusts liquid flow and pressure to maintain equalization between work cycles, ensuring accurate balancing by managing pressure differences and using a single pump for both fresh and used liquid conveyance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If balancing chambers are manufactured with small manufacturing tolerance from materials with good volume constancy, then balancing accuracy is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvebalancing accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the physical state of the balancing medium from liquid to gas, exploiting the compressibility of gas to compensate for volume variations. The gas-filled balancing chamber can expand or contract to maintain volume equilibrium without requiring precision manufacturing tolerances or special materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable balancing chamber that can be discarded after use, eliminating the need for high-precision manufacturing and durable materials. This single-use approach reduces manufacturing complexity and cost while maintaining adequate balancing accuracy for the treatment duration.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If exchange vessels are used for volumetric balancing, then device complexity is reduced, but balancing accuracy deteriorates due to material volume inconsistencies under pressure changes

Engineering Contradiction:
Improvedevice complexityVSAvoidbalancing accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameter of the balancing medium from incompressible liquid to compressible gas. This allows the exchange vessel to maintain balancing accuracy despite pressure changes during dialysis, as the gas can be compressed or expanded to compensate for volume variations without requiring complex pressure compensation mechanisms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dynamic element (gas compression/expansion) into the previously static liquid-filled exchange vessel. The gas allows the system to adapt dynamically to pressure changes during different phases of the dialysis cycle, maintaining volume equilibrium automatically without complex active control systems.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If gas bubbles are present in the dialysis liquid, then device simplicity is maintained, but balancing accuracy deteriorates due to compression of gas bubbles under pressure

Engineering Contradiction:
Improvedevice simplicityVSAvoidbalancing accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Instead of trying to eliminate gas bubbles from the dialysis liquid (the conventional approach), the patent inverts the approach by intentionally filling the balancing chamber with gas. This transforms the previously problematic gas bubbles into a useful feature that enables volume compensation under pressure changes.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of gas bubble compression into a beneficial volume compensation mechanism. The compressibility of gas, which causes balancing errors in liquid-filled systems, becomes the key mechanism for maintaining volume equilibrium in the gas-filled balancing chamber under varying pressure conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances balancing accuracy by maintaining consistent pressure and volume in the exchange vessel across work cycles, preventing incorrect balancing and ensuring precise fluid management during dialysis.

Implementation Method 1

The balancing device has a pressure sensor, which is connected to the control unit, for recording the pressure in the exchange vessel during the first, the second work cycle and during a third work cycle

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

The control unit is also designed to use the means for conveying liquid into and/or out of the exchange vessel and/or the means for interrupting the inflow of liquid into the exchange vessel and/or the outflow of liquid from the exchange vessel with a view to pressure equalization between to control the first and the second work cycle

Methodology Applied
Scientific EffectPressure equalization:

Implementation Method 3

means for delivering liquid into and/or out of the exchange vessel

Methodology Applied
Scientific EffectLiquid conveyance: Pump

Implementation Method 4

means for interrupting the inflow of liquid into the exchange vessel and/or the outflow of liquid from the exchange vessel

Methodology Applied
Scientific EffectFlow interruption: Valve

Data Source

PatentEP3116561B1Device for balancing between an inflow into and an outflow from a medical treatment device
Publication Date: 2022.01.12 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3116561B1 patent drawingFigure 1
  • EP3116561B1 patent drawingFigure 2~3
  • EP3116561B1 patent drawingFigure 4

AI summary

The invention discloses a balancing method and a balancing device (41, 410, 81, 91) for balancing between an inflow (43) into a blood treatment unit (1) of a medical treatment device and an outflow (44) from the blood treatment unit (1): The balancing device has the following: a balancing unit which has at least one exchange vessel (32), means for conveying liquid (21, 22, 72) in and/or out of the exchange vessel (32) and means for interrupting the inflow of liquid into the exchange vessel and/or the outflow of liquid from the exchange vessel (16, 12, 30, 17), and a control unit (14) for controlling the means for conveying liquid (21, 22, 72) and the means for interrupting the inflow and/or outflow of liquid (16, 12, 30, 17). The control unit is designed in such a way that the means for interrupting the inflow of liquid into the exchange vessel and/or the outflow of liquid from the exchange vessel (16, 12, 30, 17) are controlled in respect of a pressure compensation between a first and a second work cycle.