Refrigerant Recompression for Cryotherapy

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Solution Overview

Problem

Conventional cryotherapeutic systems face challenges with frequent replacement or recharging of refrigerant supply tanks, limited compatibility with refrigerants due to environmental and regulatory concerns, and inefficient refrigerant usage, leading to logistical and cost issues.

Innovation Solution

A cryotherapeutic system that recycles refrigerant by compressing and reusing it within a closed loop, allowing the use of refrigerants with more advantageous thermodynamic properties than nitrous oxide, such as hydrofluorocarbons, and reducing the need for frequent tank replacements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional cryotherapeutic systems release expanded refrigerant into the atmosphere or collect it for disposal, then the system can operate with simple refrigerant supply tanks, but the refrigerant supply must be frequently replaced or recharged, creating logistical challenges and costs

Engineering Contradiction:

Improverefrigerant supply managementVSAvoidtime for tank replacement or recharging

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent implements a refrigerant recovery system where expanded refrigerant is captured from the exhaust, compressed back to high pressure, condensed back to liquid phase, and returned to the refrigerant supply tank. This closed-loop approach eliminates the need for frequent tank replacements or recharges, directly resolving the contradiction between ease of operation and time loss.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The refrigerant is continuously circulated through the system in a closed loop, with the recovery system operating continuously to compress and return exhaust refrigerant to the supply tank. This continuous circulation eliminates interruptions for tank replacement, maintaining uninterrupted cryotherapy treatment.

Inventive Principle:

Principle #20Continuity of useful action

2Object-affected harmful factors

If conventional systems use nitrous oxide as refrigerant, then the refrigerant can be safely released into the atmosphere, but nitrous oxide has less advantageous thermodynamic properties compared to other refrigerants

Engineering Contradiction:

Improveenvironmental impact of refrigerantVSAvoidthermodynamic efficiency of refrigerant

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent converts the previously harmful disposal of expanded refrigerant into a beneficial recovery process. By capturing and compressing the exhaust refrigerant, the system enables the use of high-performance refrigerants like hydrofluorocarbons that would otherwise be problematic to dispose of, thus converting the harm of potential release into the benefit of efficient refrigerant reuse.

Inventive Principle:

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

Solution Approach 2:

The system changes the operational parameters by implementing a closed-loop refrigerant management system with compression and condensation stages. This allows the use of refrigerants with superior thermodynamic properties (higher latent heats of vaporization) that were previously unavailable due to environmental concerns about their disposal.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If larger refrigerant supply tanks are used to reduce replacement frequency, then the refrigerant supply lasts longer, but the tanks become more obtrusive and cumbersome to handle

Engineering Contradiction:

Improvefrequency of tank replacementVSAvoidhandling of refrigerant supply tank

Core Design Contradiction:

Loss of timeVSEase of operation

Solution Approach 1:

The refrigerant supply system serves itself through the automated recovery mechanism. The exhaust refrigerant is automatically compressed, condensed, and returned to the supply tank without manual intervention. This self-service approach eliminates the need for large, cumbersome tanks while maintaining continuous operation, as the system automatically replenishes its own refrigerant supply.

Inventive Principle:

Principle #25Self-service

4Temperature

If refrigerant is allowed to expand significantly in the cryo-catheter, then cooling is achieved through Joule-Thomson effect and latent heat, but the refrigerant pressure drops and requires frequent recharging

Engineering Contradiction:

Improvecooling effectiveness at cryo-applicatorVSAvoidrefrigerant pressure maintenance

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The patent utilizes phase transitions in the refrigerant cycle. The refrigerant expands and vaporizes at the cryo-applicator to achieve cooling, then the exhaust gas is compressed and condensed back to liquid phase in the recovery system. This phase transition cycle allows the refrigerant to maintain its cooling effectiveness while being continuously reused, preventing pressure drops that would require recharging.

Inventive Principle:

Principle #36Phase transitions

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 system enables long-term, cost-effective operation with reduced logistical challenges by reusing refrigerant, allowing the use of environmentally safer refrigerants with better thermodynamic properties, thus enhancing the performance and sustainability of cryotherapy procedures.

Implementation Method 1

refrigerant, which can be chilled or not chilled, expands significantly within the cryo-catheter and drops in temperature and/or absorbs heat from nearby tissue due to the Joule-Thomson effect alone or in combination with increasing latent heat

Methodology Applied

Scientific EffectJoule-Thomson effect: Joule-Thomson Effect

Implementation Method 2

Methodology Applied

Scientific EffectLatent heat: Latent Heat

Implementation Method 3

a recompression unit configured to increase a pressure of the expanded refrigerant

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentEP2928422B1Refrigerant supply system for cryotherapy including refrigerant recompression and associated devices and systems

Publication Date: 2020.02.05 MEDTRONIC ARDIAN LUXEMBOURG SARL

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AI summary

Cryotherapeutic systems configured for refrigerant recompression and associated devices, systems, and methods are disclosed herein. A cryotherapeutic system configured in accordance with a particular embodiment includes a high-pressure line, a low-pressure line, a recompression unit, and a cryo-catheter. The recompression unit increases the pressure of refrigerant from the low-pressure line to the high-pressure line to a treatment pressure sufficient for cryogenic alteration of tissue. The high-pressure line and the low-pressure line include, respectively, a first connector and a second connector. The cryo-catheter includes a shaft, a supply lumen in the shaft that is coupled to the first connector, an exhaust lumen in the shaft that is coupled to the second connector, and a cryo-applicator attached to the shaft having a cooling chamber configured to receive refrigerant from the supply lumen and to return refrigerant via the exhaust lumen to the low-pressure line.