Device for feeding a medical instrument with a refrigerant
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Solution Overview
Problem
Existing methods for supplying refrigerants to medical instruments fail to ensure proper operation when the pressure in the storage vessel falls below the required level, particularly with gases in saturated vapor form, leading to malfunctions in instruments and pressure-regulating components.
Innovation Solution
A device comprising a storage vessel, a buffer vessel with higher pressure, and a temperature control system that allows for mechanical and thermal compression to maintain the refrigerant in the desired phase and pressure, ensuring reliable operation by heating or cooling to prevent condensation or vaporization issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant pressure in the storage vessel is increased to ensure proper operation of the medical instrument, then the operational reliability is improved, but the risk of liquid droplet condensation increases which can impair function in lines, valves or the instrument
Solution Approach 1:
A buffer vessel is introduced as an intermediary between the storage vessel and the medical instrument. The buffer vessel receives refrigerant from the storage vessel and allows temperature control to prevent condensation, while still providing the instrument with sufficient pressure. This mediator decouples the direct pressure relationship between storage and instrument.
Solution Approach 2:
The temperature of the refrigerant in the buffer vessel is controlled to prevent condensation of liquid droplets. By adjusting the temperature parameter, the system maintains the refrigerant in a suitable phase state while ensuring proper pressure for instrument operation.
2Stress or pressure
If a piston pump is used to compress gas from the storage bottle to maintain pressure, then the pressure requirement for instrument operation is met, but the gas content of the bottle is only partially used leading to waste
Solution Approach 1:
The buffer vessel is pre-filled or pre-charged with refrigerant before the storage vessel pressure drops. This preliminary action ensures that when the storage pressure becomes insufficient, the buffer already contains adequate refrigerant to continue operation without needing to compress remaining gas, thus utilizing nearly 100% of the stored refrigerant.
3Reliability
If the pressure in the storage vessel is maintained at high levels to ensure instrument operation, then the instrument can operate reliably, but the refrigerant may be in liquid phase causing vapor bubbles in lines and valves
Solution Approach 1:
The temperature of the refrigerant in the buffer vessel is controlled to prevent formation of vapor bubbles. By adjusting the temperature parameter, the system maintains the refrigerant in a suitable phase state (liquid or supercritical) that eliminates vapor bubble formation while ensuring proper pressure for instrument operation.
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 solution ensures the refrigerant is supplied at the necessary pressure and phase, enhancing the operational reliability of medical instruments, especially under adverse conditions, and maintaining safety independent of the storage vessel's temperature.
Implementation Method 1
the temperature control device can be designed as a heating device... temperature control of the refrigerant, for example by heating it in a targeted manner, prevents liquid droplets from condensing out of the refrigerant
Implementation Method 2
the temperature control device can be designed, for example, as a cooling device... regulate the temperature of the refrigerant so that the liquid refrigerant does not form vapor bubbles
Implementation Method 3
the refrigerant may be subjected to mechanical compression by being compressed by a mechanical pump... a pump can be provided in addition to the temperature control device, which is connected to the storage vessel on the suction side and to the buffer vessel on the pressure side. The pump then compresses refrigerant drawn from the storage tank and feeds it to the buffer tank at increased pressure
Implementation Method 4
The refrigerant can be subjected to a thermal compression by being heated by means of the temperature control device in the buffer vessel with volume closure
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A device (10) for supplying cryosurgical instruments with a refrigerant, in particular CO2, preferably supplied in cylinders, comprises a pump (17) to supply the CO2 drawn from the cylinder to a buffer vessel (19) at a desired operating pressure, wherein the pressure in the gas cylinder may be lower than the desired operating pressure. The device (10) includes a temperature control unit (27) configured to bring the refrigerant to a desired temperature, in particular a temperature higher than the temperature in the gas cylinder or other storage vessel (15). This ensures a reliable supply of refrigerant to a cryosurgical instrument at the desired pressure and a sufficient temperature. In particular, it prevents unwanted droplet formation in the instrument or supply lines.