Closed Loop Cryosurgical Pressure Regulation
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Solution Overview
Problem
Existing cryosurgical systems fail to provide smooth and consistent pressure regulation, which is crucial for effective cryogen flow management during cryosurgical procedures.
Innovation Solution
A dual phase cryogen system with two sources (liquid and gaseous) and a closed loop configuration that includes delivery and return paths, pressure sensors, and a pump for regulating pressure, allowing for selective heating and cooling of a cryosurgical instrument tip, ensuring consistent pressure through flow regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure regulation methods are used in cryosurgical systems, then pressure control is attempted, but the pressure regulation is not smooth and consistent
Solution Approach 1:
The system employs a closed-loop feedback mechanism where pressure sensors continuously monitor pressure in both liquid and gaseous cryogen sources, and the controller adjusts the proportion of cryogen flow from each source based on real-time pressure readings. This feedback loop ensures smooth and consistent pressure regulation by dynamically balancing the contribution from liquid and gaseous sources.
Solution Approach 2:
The system changes the physical state parameter of the cryogen by utilizing both liquid and gaseous phases simultaneously. By controlling the proportion of liquid versus gaseous cryogen mixed in the common line, the system can smoothly regulate pressure without the abrupt changes that occur with conventional single-phase regulation methods.
2Ease of operation
If a dual phase cryogen system is implemented, then pressure regulation smoothness is improved, but system complexity increases
Solution Approach 1:
The system merges liquid and gaseous cryogen sources into a common delivery line, where they mix and flow together to the surgical instrument. This combination allows the benefits of both phases (liquid provides cooling capacity, gaseous provides flow flexibility) to work together, achieving smooth pressure regulation while consolidating the complexity into a unified flow path.
Solution Approach 2:
The common line serves multiple functions: it transports both liquid and gaseous cryogen, allows mixing of different phases, provides a controlled environment for phase transition, and delivers regulated cryogen to the surgical instrument. This multi-functionality reduces the need for separate dedicated pathways for each phase.
3Reliability
If cryogen flow is regulated to control pressure, then pressure consistency is improved, but energy loss may increase
Solution Approach 1:
The system recovers and recycles the spent cryogen gas from the surgical site back to the cryogen sources. The pump returns the exhausted gas to the liquid cryogen source, where it can be condensed back to liquid phase and reused. This recovery process minimizes energy loss by preventing the need to continuously produce new cryogen.
Solution Approach 2:
The system maintains continuous flow and pressure regulation of cryogen through the surgical instrument, ensuring consistent cooling without interruptions. The continuous operation of the pump and flow regulators keeps the cryogen delivery system in an optimal state, minimizing energy losses that would occur during start-stop operations or pressure fluctuations.
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 achieves smooth, constant pressure regulation, effectively controlling heat flux and maintaining desired pressures in the cryosurgical system, enhancing the precision and efficiency of cryosurgical procedures.
Implementation Method 1
a first source heater therein that selectively heats the liquid phase cryogen so as to convert at least some of the liquid phase cryogen stored therein into gaseous phase cryogen
Implementation Method 2
a pump that selectively increases a local pressure in the cryogen return path
Implementation Method 3
a pressure regulator that regulates the pressure of the first source based on information from the pressure sensors
Data Source
AI summary
A system for selectively cooling and warming a cryosurgical instrument using a dual phase cryogen, including: two sources of the cryogen, a first source storing liquid phase cryogen and having a first source heater therein that selectively converts at least some of the liquid phase cryogen into gaseous phase cryogen and a second source storing the gaseous phase cryogen; a cryogen delivery control section selectively delivering cryogen to the tip; a cryogen return path from the tip to the first and second sources; a cryogen return control section that includes a pump that pumps the returning cryogen to the second source; and a pressure control section including a first pressure sensor that senses a pressure in the first source, a second pressure sensor that senses a pressure in the second source, and a pressure regulator that regulates the pressure of the first source based on information from the pressure sensors.