Dewar Vessel Coolant Recirculation for Ice-Free Sample Access
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Solution Overview
Problem
Dewar vessels face challenges in providing reliable cooling while allowing easy access to samples, as frequent opening leads to ice contamination of the coolant, and samples are typically stored at the bottom for optimal cooling, complicating handling and throughput.
Innovation Solution
A pseudo-static pump is integrated into the Dewar vessel, using a chamber with a closing element and pressure increasing device to recirculate coolant, such as liquid nitrogen, to an upper part of the vessel, maintaining a constant coolant level and minimizing ice contamination, with a simple design that reduces maintenance and external connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If samples are stored at the bottom of the Dewar vessel for optimal cooling, then cooling reliability is improved, but sample accessibility and handling are worsened
Solution Approach 1:
The system divides the coolant distribution into two zones: a reservoir at the bottom and a distribution chamber at the top. The pump segments the coolant flow path, extracting coolant from the bottom reservoir and redistributing it to the top chamber, thereby decoupling the cooling source location from the sample storage location.
Solution Approach 2:
The pump acts as an intermediary device between the bottom reservoir and top distribution chamber. It mediates the coolant transfer process, enabling coolant to move from the cooling source at the bottom to the distribution point at the top, where samples are stored for easy access.
2Ease of operation
If the Dewar vessel is opened frequently for high throughput sample access, then sample accessibility is improved, but ice contamination of the coolant is worsened
Solution Approach 1:
The pump operates continuously or in repeated cycles to maintain a constant level of coolant in the top distribution chamber. This continuous action ensures that samples remain immersed in coolant even when the Dewar is opened, eliminating the need to close the vessel to prevent contamination.
Solution Approach 2:
The system changes the operational parameter of coolant level from variable to constant. By actively maintaining a constant coolant level in the distribution chamber, the system allows the Dewar to remain open without exposing samples to ice contamination, as the coolant continuously covers the samples.
3Productivity
If a complex pump system with moving mechanical parts is used for coolant circulation, then pumping functionality is improved, but maintenance requirements and device complexity are worsened
Solution Approach 1:
The invention replaces complex mechanical pump systems with a simplified pressure-based circulation mechanism. By using pressure increases from gas injection or thermal expansion to drive coolant circulation, the system eliminates complicated moving parts while maintaining effective coolant pumping capability.
Solution Approach 2:
The simplified pump system requires minimal external control and maintenance. The pressure-based mechanism automatically circulates coolant without requiring complex mechanical assemblies, bearings, or seals that would need regular maintenance, thereby reducing device complexity and maintenance requirements.
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 pump ensures reliable cooling with easy access to samples by maintaining a constant coolant level and minimizing ice contamination, allowing for high throughput and efficient operation with reduced maintenance and external connections.
Implementation Method 1
The closing element is adapted to automatically close the chamber by floating when the chamber is filled by coolant
Implementation Method 2
the pressure increasing device is adapted to increase the pressure within the chamber after the chamber is partly or totally filled with the coolant, and until part of or all of the fluid is released through the outlet
Implementation Method 3
The chamber is adapted to fill automatically by gravity flow through the inlet
Data Source
AI summary
The present invention relates to a pump (15) for pumping a coolant (9) within a Dewar vessel (1) and to a corresponding Dewar vessel (1) for storing samples in a coolant (9). The Dewar vessel (1) comprises a thermally insulated reservoir (3) for the coolant (9) and a sample vessel (11) provided separately and arranged in the thermally insulated reservoir (3). The reservoir (3) is connected to the sample vessel (11) in such a way that the level of coolant (9) is constant in the sample vessel (11). Pump (15) may help in keeping the level of coolant (9) in the sample vessel (11) constant. For this purpose the pump (15) comprises a chamber (17) with an inlet (19) and an outlet (21), a closing element (23) and a pressure increasing device (25). Therein, the inlet (19) is connectable to the reservoir (3) and the outlet (21) is connectable to a sample vessel (11) of the Dewar vessel (1). The chamber (17) is adapted to fill with coolant (9) through the inlet (19) by gravity and the closing element (23) is adapted to automatically close the chamber (17) when it is full of coolant (9). The pressure increasing device (25) is adapted to increase the pressure within the chamber (17), after the chamber (17) is closed, until the coolant (9) is released through the outlet (21).