Cryogenic Vessel Pressure Sensing for Real-Time Fluid Estimation
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Solution Overview
Problem
Existing cryogenic fluid delivery systems face challenges in accurately estimating the amount of cryogenic fluid remaining in a supply vessel during and after a procedure, especially when manual control of freeze/thaw cycles is required, leading to potential incomplete tissue treatment if fluid is consumed prematurely.
Innovation Solution
A method involving the release of pressure from the cryogenic fluid supply vessel at a predetermined frequency via a control valve, detection of disturbances in a pressure feedback sensor signal, and estimation of fluid volume based on the magnitude of these disturbances, allowing real-time monitoring of fluid levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load cell is used to detect the volume of cryogenic fluid in the fluid supply vessel, then the volume can be confirmed prior to starting the procedure, but the load cell may lose its ability to accurately estimate the volume during the procedure due to seal formation force saturating or corrupting the load signal
Solution Approach 1:
The patent introduces a pressure sensor as an intermediary measurement device. Instead of directly measuring fluid volume with a load cell, the system measures pressure changes in the gas space above the cryogenic fluid. This intermediary approach allows continuous volume estimation without the seal formation forces that corrupt load cell signals, resolving the contradiction between initial measurement accuracy and continuous monitoring reliability.
Solution Approach 2:
The patent replaces the mechanical load cell measurement system with a pressure-based measurement system. By substituting mechanical force measurement with pressure sensing, the system avoids the saturation and corruption issues that occur with load cells during seal formation, enabling reliable continuous volume estimation throughout the procedure.
2Extent of automation
If the cryogenic delivery system operates in automatic mode with a preestablished amount of cryogenic fluid, then the procedure can run for a preset amount of time, but the user cannot manually control freeze/thaw times and assess fluid consumption in real-time
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors cryogenic fluid volume via pressure sensors and provides real-time information to the user. This feedback system enables operators to manually control freeze/thaw cycles while being informed of current fluid levels, combining the benefits of automation with manual control flexibility. The feedback allows real-time assessment of fluid consumption without restricting operational freedom.
3Measurement precision
If pressure is released from the cryogenic fluid supply vessel at a predetermined frequency to enable real-time volume estimation, then accurate fluid level assessment is possible during the procedure, but additional control components and monitoring complexity are introduced
Solution Approach 1:
The patent employs periodic pressure release cycles at predetermined frequencies to enable real-time volume estimation. By using periodic action rather than continuous pressure modulation, the system achieves measurable pressure variations for volume calculation while minimizing the complexity of continuous control mechanisms. The periodic nature of the pressure release simplifies the control system compared to continuous modulation approaches.
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
Enables accurate, real-time assessment of cryogenic fluid levels throughout a procedure, ensuring sufficient fluid is available to complete treatment cycles and preventing incomplete tissue freezing.
Implementation Method 1
detecting a disturbance in an output signal of a pressure feedback sensor
Implementation Method 2
releasing pressure from the cryogenic fluid supply vessel at a predetermined frequency via a control valve
Data Source
AI summary
A method for estimating an amount of cryogenic fluid in a cryogenic fluid supply vessel comprises releasing pressure from the cryogenic fluid supply vessel at a predetermined frequency via a control valve. The method also comprises detecting a disturbance in an output signal of a pressure feedback sensor. The disturbance occurs at the predetermined frequency. The method additionally comprises determining a magnitude of the disturbance in the output signal of the pressure feedback sensor and estimating the amount of the cryogenic fluid in the cryogenic fluid supply vessel based on the magnitude of the disturbance in the output signal of the pressure feedback sensor.