Portable Cryosurgical Device With Zero-Dead-Volume Cryogen Delivery
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Solution Overview
Problem
Existing cryosurgical devices are complex, costly, and inefficient in delivering high-pressure, low-boiling point cryogens, often requiring specialized equipment, posing safety hazards and limiting treatment duration due to limited reservoirs and awkward patient positioning.
Innovation Solution
A portable, ergonomic cryosurgical device with a solenoid valve system and omni-directional wand that delivers metered doses of cryogenic fluids like carbon dioxide and nitrous oxide, featuring a quick-change cylinder system and real-time cryogen level indication, ensuring consistent treatment times and ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cryosurgical devices use liquid nitrogen or complicated valving mechanisms to deliver liquefied gases, then colder temperatures can be achieved, but the device structure becomes complex and manufacturing cost increases
Solution Approach 1:
The patent extracts the complex valving mechanism from the system by using a simple push-button actuator that directly opens a valve in the cryogen container, eliminating the need for complicated external valving mechanisms while maintaining the ability to deliver cold cryogenic temperatures
Solution Approach 2:
The system uses the pressure of the stored cryogenic gas itself to drive the dispensing process, with the gas pressure automatically controlling the flow through the needle valve without requiring external mechanical valving mechanisms
2Ease of operation
If handheld pressurized containers use compressed gases like butane or propane for cryosurgery, then portability is improved, but the evaporation rate becomes too slow and treatment duration is limited
Solution Approach 1:
The patent changes the physical parameters of the system by switching from low-pressure compressed gases to high-pressure liquid cryogens stored at their boiling points, which dramatically increases the evaporation rate and extends treatment duration while maintaining portability
Solution Approach 2:
The system utilizes the phase transition of cryogenic liquids (liquid to gas) at controlled rates by adjusting the valve opening, allowing sustained treatment duration through regulated evaporation of the liquid cryogen
3Temperature
If cryosurgical devices use high-pressure liquefied gases with low boiling points, then colder temperatures are achieved, but safety hazards increase due to handling difficulties
Solution Approach 1:
The patent introduces an intermediary needle valve mechanism that allows precise control of the cryogen flow, mediating between the high-pressure storage container and the application point to safety manage the release of cold cryogenic temperatures
Solution Approach 2:
The system uses a small opening in the needle valve to control the cryogen flow rate, applying only the necessary amount of cold cryogen needed for treatment rather than allowing uncontrolled release, thereby reducing safety hazards
4Volume of moving object
If limited reservoirs are used in portable cryosurgical devices, then device size is reduced, but the effective temperature is reached for only a short period
Solution Approach 1:
The patent ensures continuous useful action by maintaining the cryogen reservoir at its boiling point through pressure equilibrium, allowing the liquid to continuously evaporate and maintain effective cryogenic temperatures throughout the treatment duration without interruption
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 device provides economical, reliable, and versatile cryosurgical treatments with customizable freeze-thaw cycles, minimizing damage to healthy tissue and reducing per-use costs by allowing multiple uses without disposable components.
Implementation Method 1
The solenoid valve includes a valve body with a valve seat, an inlet port on an inlet side of the valve seat that introduces the cryogen from the cryogen source into the valve body, an outlet port on an outlet side of the valve seat that receives the cryogen from the valve body, and a piston movable to cause the valve seat to move from a closed position preventing passage of the cryogen from the inlet side of the valve seat to the outlet side of the valve seat to an open position permitting the passage of the cryogen from the inlet side of the valve seat to the outlet side of the valve seat
Implementation Method 2
Such cryosurgical devices generally rely upon a liquefied (compressed) gas, such as butane, propane, or dimethyl ether (DME), and others to rapidly cool an applicator tip or 'bud' based on the principles of 'heat of vaporization.' As the compressed gas flows to and contacts a surface of an applicator, such as a porous applicator bud, rapid evaporation of the gas causes the applicator surface to cool to temperatures that are lower than the boiling point of the liquefied gas alone
Implementation Method 3
Direct spray methods for such localized freezing are governed by the 'Joules Thomson' effect due to expansion of the cooling liquid
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
The portable cryosurgical device is economical, easy to use and operate, and delivers cryogenic material such as nitrous oxide and carbon dioxide gas in any direction or orientation. The delivered materials destroy target tissue using extremely cold temperatures and the abrasives formed when the cryogenic material becomes a solid. The device includes a portable countertop enclosure housing a cryogen source, a cryogen flow tube in fluid communication with the cryogen source, and a flow path assembly. The flow path assembly includes a valve between the cryogen source and the cryogen flow tube having substantially zero dead volume. The flow path assembly can include a quick-connect cryogen tank adapter and an in-line cryogen filter. The flow path assembly delivers liquefied compressed gas from the cryogen source to a terminal end of the cryogen flow tube without a phase change occurring in the flow path.