Centrifuge Cooling and Depressurization Sequence
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Solution Overview
Problem
Centrifuges with high-speed rotors require long depressurization times and extended cooling periods due to the dominance of radiation-based heat exchange in a vacuum environment, leading to a trade-off between friction heat reduction and cooling efficiency, especially when handling samples that need to be cooled to low temperatures.
Innovation Solution
A centrifuge design that initiates cooling without depressurization, using a cooling unit to pre-cool the rotor chamber, and then deploys a depressurization unit after a predetermined time has elapsed, allowing for parallel cooling and depressurization, thereby reducing overall cooling time and suppressing long depressurization periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rotor chamber is depressurized to reduce friction heat, then friction heat reduction is achieved, but cooling time of the rotor and sample increases due to dominant radiation-based heat exchange
Solution Approach 1:
The patent applies preliminary action by cooling the rotor and sample in the atmospheric pressure environment before depressurization. The cooling unit operates initially while the rotor chamber is still at atmospheric pressure, allowing convective cooling to reduce the temperature of the rotor and sample. Only after this preliminary cooling phase does the depressurization unit activate, thereby avoiding the slow radiation-based cooling that occurs in vacuum conditions.
2Productivity
If cooling is performed in atmospheric pressure environment, then cooling efficiency improves due to convection, but depressurization time increases due to evaporation of dew water and ice
Solution Approach 1:
The patent applies preliminary action by completing the cooling process before depressurization. The cooling unit operates first to reduce the temperature of the rotor chamber and its contents to below the dew point, preventing dew water and ice formation during subsequent depressurization. This preliminary cooling action eliminates the need for extended depressurization time that would otherwise be required to evaporate condensed moisture.
3Loss of time
If cooling and depressurization are performed concurrently, then time is saved, but cooling efficiency is reduced due to dominant radiation-based heat exchange
Solution Approach 1:
The patent applies segmentation by dividing the cooling and depressurization processes into distinct temporal phases. The cooling phase occurs first in atmospheric pressure conditions, utilizing efficient convective heat transfer. After cooling is sufficient, the depressurization phase begins, and the cooling unit continues operating to maintain temperature control during the transition to vacuum conditions. This segmentation allows each process to operate under optimal conditions.
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
This approach significantly shortens the cooling time of the rotor and sample, allowing for faster temperature attainment and sample separation while minimizing the duration of the depressurization process, thus overcoming the limitations of traditional methods.
Implementation Method 1
heat exchange based on convection
Implementation Method 2
heat exchange based on radiation
Implementation Method 3
depressurizes a rotor chamber
Implementation Method 4
friction heat between air in the rotor chamber and the rotor
Data Source
AI summary
A centrifuge capable of suppressing a long-time depressurization as compared with the case of starting depressurizing after cooling has been completed as well as shortening a cooling time of a rotor and a sample in the rotor is achieved as compared with the case of starting cooling is at the same time with depressurization. Operation of a Peltier element is started at the same time with operation start of the centrifuge. A bowl is cooled by heat absorption of the Peltier element, and the rotor is cooled by the bowl with using ambient air as a thermal medium. At this time, a vacuum pump depressurizing a rotor chamber is in an OFF state (ambient conditions). After a predetermined time is elapsed, the vacuum pump is turned on to start depressurization of the inside of the rotor chamber.