Sample Processing Fluidics With Feedback-Controlled Sheath Flow
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Solution Overview
Problem
The stability of fluid delivery in sample processing instruments, such as flow cytometers, is crucial for accuracy, but factors like container height changes, peristaltic pumps, and pressure fluctuations can cause unstable fluid rates, leading to reduced accuracy.
Innovation Solution
A fluidic system with a sheath supply pipeline, flow sensor, and control device to maintain a stable flow rate, incorporating a damping device, inflation pipeline, and degassing device to stabilize sheath delivery, and a method to control the sheath pump using feedback from the flow sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If peristaltic pumps are used to deliver fluids, then fluid delivery capability is achieved, but large fluctuations in fluid flow rate occur
Solution Approach 1:
The patent implements a feedback control system where a flow sensor continuously monitors the actual flow rate of the sheath fluid and feeds this information back to the control device. The control device compares the measured flow rate with the target flow rate and adjusts the peristaltic pump's rotation speed accordingly, creating a closed-loop control system that automatically stabilizes fluid delivery despite pump-induced fluctuations
Solution Approach 2:
The patent makes the peristaltic pump's rotation speed variable rather than fixed. The control device dynamically adjusts the pump's rotation speed based on real-time flow rate measurements, allowing the system to adapt to changing conditions and maintain stable fluid delivery. This dynamic adjustment transforms the pump from a static component into a controllable variable element
2Adaptability or versatility
If container height changes occur, then fluid storage flexibility is improved, but gravitational potential energy changes cause unstable fluid delivery
Solution Approach 1:
The flow sensor continuously monitors the actual flow rate and provides feedback to the control device. When container height changes cause gravitational potential energy variations that affect flow stability, the feedback system detects these changes and automatically adjusts the pump's rotation speed to compensate, maintaining stable fluid delivery despite container position variations
Solution Approach 2:
The system changes the operational parameters of the peristaltic pump dynamically. By adjusting the pump's rotation speed based on real-time flow rate measurements, the system compensates for gravitational effects caused by container height changes, maintaining consistent fluid delivery across different container positions
3Speed
If pressure changes occur in the fluid, then fluid delivery speed can be adjusted, but velocity changes reduce measurement accuracy
Solution Approach 1:
The flow sensor provides continuous feedback on the actual flow rate to the control device. When pressure changes cause velocity fluctuations that affect measurement accuracy, the feedback system detects these deviations and adjusts the pump's rotation speed to maintain consistent flow rates, ensuring accurate measurements despite pressure variations
Solution Approach 2:
The system dynamically adjusts the peristaltic pump's rotation speed based on real-time flow rate measurements. This dynamic control allows the system to maintain stable fluid delivery and accurate measurements even when pressure changes occur, transforming a static system into one that can adapt to pressure variations
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
Ensures consistent fluid delivery to the flow cell, enhancing the accuracy and stability of sample processing instruments by reducing fluctuations and maintaining predetermined flow rates.
Implementation Method 1
a flow sensor for sensing a flow rate of the sheath supplied to the flow cell
Implementation Method 2
a damping device provided on the sheath supply pipeline, and configured to reduce or eliminate fluctuation of the sheath in the sheath supply pipeline
Implementation Method 3
a degassing device provided on the sheath supply pipeline, and configured to eliminate or discharge air bubbles in the sheath
Data Source
AI summary
The present application relates to a fluidic system of a sample processing instrument, a sample processing instrument, and a method of delivering fluids in a sample processing instrument. The sample processing instrument includes a flow cell for passage and processing of a sample. The fluidic system includes: a sheath supply pipeline connecting a sheath container to the flow cell, wherein the sheath supply pipeline is provided with a sheath pump for pumping sheath and a flow sensor for sensing a flow rate of the sheath supplied to the flow cell; a sample supply pipeline connecting a sample container to the flow cell; and a control device configured to control or adjust the flow rate of the sheath to a predetermined value based on the measurement of the flow sensor.