Heat Pipe Infusion Warmer with Helical Flow Path

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Solution Overview

Problem

Existing medical infusion fluid warming systems face challenges in providing stable and efficient heat transfer over a range of flow rates while minimizing heat loss to the surroundings, maintaining low infection risk, and ensuring cost-effective manufacturing, particularly in compact and portable designs.

Innovation Solution

The use of an elongate heat pipe with a working fluid undergoing phase transition, combined with a positive temperature coefficient heater and a helical infusion fluid flow path, ensures efficient heat transfer to the fluid, maintaining a stable temperature of 37°C, and allowing for easy replacement of disposable components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a heat exchanger connected with a circulating supply of warmed water is used, then heat transfer efficiency is improved, but device complexity and risk of infection increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts the circulating water system from the device, replacing it with a disposable heat-exchange element that is pre-filled with warmed fluid. This eliminates the need for complex circulating pumps, reservoirs, and plumbing while maintaining effective heat transfer to the infusion fluid.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs a disposable heat-exchange element that is discarded after a single use. This eliminates the need for complex reusable components requiring sterilization and maintenance, reducing both device complexity and infection risk while maintaining thermal efficiency.

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

2Volume of moving object

If a compact design is implemented, then portability is improved, but heat transfer efficiency may worsen

Engineering Contradiction:
Improvedevice volumeVSAvoidheat transfer efficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The heat-exchange element is designed to fit within or around the infusion fluid container, nesting the heating function within the existing structure. This maximizes heat transfer surface area within a compact volume, maintaining thermal efficiency while minimizing device size for portability.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Power

If electrical resistance heaters are used, then heating capability is improved, but risk of infection and electrical isolation requirements increase

Engineering Contradiction:
Improveheating capabilityVSAvoidinfection risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The heating element is implemented as a disposable component that is discarded after use, eliminating the need for complex electrical isolation and sterilization protocols associated with reusable electrical heaters. The disposable nature prevents infection risk while maintaining effective heating capability.

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

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 achieves stable and efficient heat transfer to infusion fluids, reducing temperature fluctuations and ambient cooling, making it suitable for portable use and low-cost manufacturing, while ensuring patient safety and effective temperature control.

Implementation Method 1

an elongate heat pipe of the kind containing a working fluid that operates using phase transition between a vapour and a liquid

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

the apparatus includes an elongate heat pipe of the kind containing a working fluid that operates using phase transition between a vapour and a liquid

Methodology Applied
Scientific EffectHeat pipe: Heat Pipe

Implementation Method 3

the heat pipe transfers heat to the fluid flowing along the flow path

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 4

The heat source may include a positive temperature coefficient heater

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 5

a positive temperature coefficient heater

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP2950847B1Medical infusion fluid heat exchange apparatus and warming systems
Publication Date: 2020.05.06 ICU MEDICAL INTERNATIONAL LTD
  • EP2950847B1 patent drawingFigure 1~2
  • EP2950847B1 patent drawingFigure 3~4

AI summary

Apparatus for warming medical infusion fluids includes a heat pipe (12) warmed by an electrical heater (17) at one end. A replaceable fluid flow path (20) of helical configuration extends along the heat pipe (12) and is formed between an inner, thermally-conductive sleeve (21) with a helical profile and an outer insulative sleeve (26). An inlet (3) to the flow path (20) is located adjacent the heater (17), the outlet (4) being at the opposite end of the heat pipe (12). The inlet (3) is connected to a suspended saline bag (1) and the outlet (4) connects via tubing (5) to a catheter (6) inserted in a blood vessel. A temperature sensor (18) in the outlet tubing (5) provides a feedback output to a control unit (11) that controls operation of the heater (17) to maintain a stable temperature.