Cryotherapy Probe Supercritical Nitrogen Cooling
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Solution Overview
Problem
Current cryotherapy systems face challenges with inefficient self-contained designs, high costs, and limitations in probe size and cooling capacity due to vapor lock issues with liquid nitrogen and complex gas-based systems, which hinder the adoption and effectiveness of cryotherapy in medical treatments.
Innovation Solution
The development of cryotherapy probes that utilize a near-critical nitrogen cooling method, where liquid nitrogen is compressed to its critical point to avoid vapor lock and increase cooling efficiency, allowing for smaller probe diameters and more efficient cryogenic systems, along with integrated features like multifunctional electrical wiring for temperature monitoring and stimulation, and injection ports for enhanced treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If liquid nitrogen is used for cooling in cryotherapy probes, then high cooling capacity is achieved, but vapor lock issues occur and probe size increases
Solution Approach 1:
The patent changes the physical parameters of nitrogen by compressing it to supercritical conditions (above critical pressure of 33.5 atm and critical temperature of -147°C), transforming it from a liquid that suffers vapor lock to a supercritical fluid that maintains continuous flow and provides efficient cooling without phase change issues
Solution Approach 2:
The patent utilizes the phase transition properties of nitrogen by operating it in the supercritical region where distinct liquid and gas phases disappear, allowing continuous flow without vapor lock while maintaining high density and cooling capacity, thus enabling smaller probe design
2Reliability
If gas-based cryotherapy systems are used, then vapor lock is avoided, but system complexity and device size increase
Solution Approach 1:
The patent transforms nitrogen into a supercritical fluid by controlling pressure and temperature parameters, which eliminates vapor lock issues inherent in gas-based systems while maintaining flow continuity and cooling efficiency, thereby reducing system complexity
Solution Approach 2:
The patent replaces complex mechanical vapor lock prevention mechanisms with a thermodynamic solution using supercritical nitrogen, where the fluid's properties naturally prevent vapor lock, simplifying the overall system design
3Reliability
If conventional cryotherapy probes are used, then treatment is effective, but manufacturing costs and probe price are high
Solution Approach 1:
The patent uses supercritical nitrogen instead of expensive liquid nitrogen storage and handling systems, reducing manufacturing complexity and costs while maintaining effective cooling performance for cryotherapy treatment
Solution Approach 2:
The patent enables the use of disposable probes with integrated supercritical nitrogen delivery, eliminating the need for expensive reusable components and complex storage infrastructure, thereby reducing overall system cost
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 approach enables high cooling capacity with reduced probe size, simplifies system design, lowers manufacturing costs, and improves the reliability and efficiency of cryotherapy treatments by minimizing vapor lock issues and optimizing gas flow, making cryotherapy more viable for precise and effective medical applications.
Implementation Method 1
A heat exchanger is disposed within the shaft in thermal communication with the supply conduit and return conduit to exchange heat from gas in the supply conduit to gas in the return conduit
Implementation Method 2
A vacuum jacket is adapted to provide thermal isolation of the heat exchanger from the shaft
Implementation Method 3
These devices take advantage of the fact that non-ideal gases, when rapidly expanded, become extremely cold. In these devices, a high pressure gas such as argon or nitrogen is expanded through a nozzle inside a small cylindrical sheath made of steel, and the JT expansion cools the steel sheath to sub-freezing cryogenic temperature very rapidly
Data Source
AI summary
A gas-based cryotherapy probe is provided with a shaft having a closed distal end adapted for insertion into a body. A supply conduit is disposed longitudinally within the shaft for flowing gas towards the distal end, and a return conduit is disposed longitudinally within the shaft for flowing gas from the distal end. The gas is maintained at a lower pressure within the return conduit than in the supply conduit. A heat exchanger is disposed within the shaft in thermal communication with the supply conduit and return conduit to exchange heat from gas in the supply conduit to gas in the return conduit. A vacuum jacket is adapted to provide thermal isolation of the heat exchanger from the shaft.