Centrifuge Rotor Chamber Temperature Control During Deceleration
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Solution Overview
Problem
Centrifuges face issues with excessive cooling of samples during slow rotor deceleration, leading to lowered process quality due to temperature differences between the rotor and rotor chamber, especially at higher rotation speeds.
Innovation Solution
A centrifuge with a control unit that adjusts the target controlled temperature of the rotor chamber from a first to a second target temperature, higher than the first, during deceleration, using a compressor and bypass pipe to maintain the rotor chamber temperature closer to the set temperature, preventing excessive cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotor is rotated at high speed, then the centrifugal separation effect is improved, but the temperature of the rotor rises due to friction heat
Solution Approach 1:
The cooling apparatus is activated before the rotor rotation starts and continues cooling during the deceleration phase. This preliminary and extended cooling action prevents the rotor temperature from rising excessively during high-speed operation and compensates for the friction heat generated.
Solution Approach 2:
The control apparatus dynamically adjusts the cooling apparatus operation parameters based on the rotor's rotation speed. When the rotor rotates at high speed, the cooling apparatus operates at higher capacity; when the rotor decelerates, the cooling apparatus continues to operate to maintain temperature, effectively managing the temperature parameter throughout the rotation cycle.
2Temperature
If the cooling apparatus operates continuously to maintain rotor temperature, then the rotor temperature control is improved, but the sample may be excessively cooled during deceleration
Solution Approach 1:
The control apparatus continuously monitors the rotor temperature and uses this feedback to adjust the cooling apparatus operation. During deceleration, when the rotor generates less friction heat, the control apparatus reduces or stops the cooling apparatus operation based on temperature feedback, preventing excessive cooling of the sample while maintaining rotor temperature control during high-speed operation.
3Productivity
If the rotor decelerates slowly to maintain separation quality, then the separation effect is improved, but the rotor chamber temperature drops causing excessive cooling
Solution Approach 1:
The control apparatus is programmed to stop the cooling apparatus operation in advance during the deceleration phase, before the rotor chamber temperature can drop significantly. This preliminary action prevents the excessive cooling of the sample that would otherwise occur during slow deceleration, while still allowing the rotor to maintain its separation quality.
4Use of energy by stationary object
If the cooling apparatus is stopped when the rotor reaches set temperature, then energy consumption is reduced, but the rotor temperature rises due to friction heat during operation
Solution Approach 1:
The cooling apparatus operates continuously throughout the rotor rotation cycle, including during high-speed operation and deceleration, rather than being stopped when the set temperature is reached. This continuous operation ensures that the rotor temperature is maintained within the desired range despite friction heat generation, while the control apparatus optimizes the cooling capacity to avoid excessive energy consumption.
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 prevents excessive cooling of the sample, maintaining the rotor chamber temperature close to the set temperature during deceleration, thus preserving the quality of the centrifugal process even at higher rotation speeds.
Implementation Method 1
a centrifuge has installed therein a rotor to which a container, such as tube or bottle, in which samples such as culture broth or blood is accommodated is loaded. The rotor is driven to rotate with a driving device such as electric motor. Upon a centrifuging process on a sample in the storing container, the rotor is rotated at a high speed
Implementation Method 2
a refrigerator (freezing machine) in which a cooling medium is circulated in a cooling pipe that is wound around a storing container
Implementation Method 3
The refrigerator used as a cooling apparatus cools the rotor chamber by driving a motor of a compressor for sending out a coolant to circulatory supply the coolant in a cooling pipe
Implementation Method 4
When a rotor is rotated in this manner in which air exists in the rotor chamber, heat of friction of air and the rotor generated during the rotation of the rotor may be bigger and it might rise the temperature of the sample
Data Source
AI summary
Lowering of process quality of a sample is prevented even when a rotor is slowly decelerated taking a long time upon finishing a centrifugal process. A centrifuge having a steady operation mode of rotating a rotor at an inputted steady rotation speed and a deceleration stop mode of stopping the rotor by deceleration. When a remaining time of the steady operation mode is within a stop preparation time, a target controlled temperature of the rotor chamber is set from a first target controlled temperature to a second target controlled temperature that is higher than the first target controlled temperature. By setting the target controlled temperature of the rotor chamber high before switching to the deceleration stop mode, temperature of the rotor chamber is controlled to be close to a set temperature of the rotor and thus excessive cooling of a sample loaded to the rotor can be prevented.