Multi-Lumen Heat Exchanger with Nested Lumens
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Solution Overview
Problem
Existing heat exchangers for warming physiological solutions are costly due to the use of aluminum and require complex manufacturing processes, with inefficiencies in heating and heat loss due to convective heating from only the inner conduit and exposure to the ambient environment.
Innovation Solution
A heat exchanger with a one-piece tubing configuration featuring a central lumen, a middle lumen, and an outer lumen made of medical-grade plastics, where a heated fluid circulates through both the central and outer lumens to efficiently heat the infusate without direct heat loss to the ambient environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an aluminum inner conduit with spiral configuration is used for convective heating, then heating efficiency is improved, but manufacturing cost increases and manufacturing complexity increases
Solution Approach 1:
The patent replaces expensive aluminum material with disposable medical-grade plastic tubing that can be manufactured through simple extrusion processes. The plastic tubing with integrated spiral channels provides adequate heating functionality at a fraction of the cost of aluminum, accepting that the component is single-use in medical applications.
Solution Approach 2:
The patent changes the material parameter from metal (aluminum) to polymer (medical-grade plastic) and modifies the structural parameter by integrating the spiral heating channels directly into the tubing wall during extrusion, rather than requiring separate spiral configuration steps. This simplifies manufacturing while maintaining heating efficiency.
2Loss of energy
If an aluminum inner conduit with spiral configuration is used for convective heating, then heating efficiency is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the heating channel structure directly into the tubing wall during the extrusion process. The spiral heating channels are formed as integral part of the plastic tubing construction, eliminating the need for separate steps to create spiral configurations and assemble multiple components. This single-step integration dramatically reduces manufacturing process complexity.
3Device complexity
If only the inner conduit is heated by heated water, then heating process is simplified, but heat loss increases due to infusate contacting the outer conduit exposed to atmosphere
Solution Approach 1:
The patent implements a nested concentric lumen structure where the infusate flows through the central lumen, surrounded by a middle lumen carrying heated water, which is in turn surrounded by an outer lumen. This nested arrangement allows heated water to contact both the inner and outer surfaces of the infusate pathway, providing heating from both directions and eliminating heat loss to the atmosphere.
Solution Approach 2:
The patent applies different thermal functions to different regions of the tubing structure. The middle lumen carries heated water that transfers heat radially inward to the infusate in the central lumen and radially outward to prevent heat loss from the outer conduit. This localized thermal management ensures efficient heating while minimizing heat loss to the environment.
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 provides efficient heating of the infusate with reduced heat loss, as the heated fluid recirculates through both lumens, maintaining temperature regulation and minimizing manufacturing costs by using a simpler extrusion method with medical-grade plastics.
Implementation Method 1
the infusate that flows through the middle lumen of the heat exchanger tubing is enveloped by heat from the heating fluid
Implementation Method 2
the infusate is heated by convection from the wall of the inner conduit
Data Source
AI summary
A heat exchanger has a multi-lumen tubing having one end connected to a supply fitting and another end connected to a return fitting. The tubing has a central lumen, a middle lumen that surrounds the central lumen and an outer lumen that surrounds the middle lumen. When infusate traverses along the heat exchanger, it is heated by the heating fluid that flows along the central lumen, and also by the rerouted heating fluid that flows along the outer lumen of the tubing. The heat exchanger is fluidly coupled to a heater by its inlet and outlet so that the temperature of the heating fluid for warming the infusate is maintained at a predetermined temperature.