Closed Fluid Delivery System with Dynamic Pump Speed Control
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Solution Overview
Problem
Conventional fluid delivery systems for cell culture face challenges in preventing contamination and stirring of waste fluids, particularly when the aspiration port of the delivery pump approaches the cultured cells, leading to splashing and potential contamination of the workspace.
Innovation Solution
A closed fluid delivery system with a delivery pump that adjusts its feed speed based on the remaining fluid amount in the container, incorporating a filter for absorbing fungi, bacteria, and foreign matter, and using a footswitch for speed control to minimize radical changes in aspiration speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the aspiration port of the delivery pump is positioned to aspirate waste fluid efficiently, then the aspiration speed can be increased to improve productivity, but the aspiration port may come close to the cultured cells causing contamination and workspace contamination
Solution Approach 1:
The delivery pump's feed speed is made dynamically adjustable based on the remaining waste fluid amount. When waste fluid level is high, the pump operates at higher speed for efficient aspiration. When waste fluid level decreases and the aspiration port approaches cultured cells, the pump automatically reduces speed to prevent contamination, thus resolving the contradiction between productivity and contamination risk
Solution Approach 2:
The system incorporates feedback control where the controller monitors the remaining waste fluid amount and adjusts the delivery pump's feed speed accordingly. This closed-loop control ensures that aspiration speed is optimized for productivity when safe, and reduced when contamination risk increases, dynamically balancing both requirements
2Device complexity
If linear control values are outputted from the controller to the delivery pump, then the control system remains simple, but radical changes in aspiration speed occur when waste fluid remaining amount is reduced, causing waste fluid ruffling and cell aspiration
Solution Approach 1:
The system changes the control parameter relationship from direct linear correspondence to a non-linear relationship where small changes in control values produce even smaller changes in feed speed when waste fluid is low. This parameter transformation allows the simple linear controller to produce stable, gradual speed adjustments that prevent aspiration turbulence and cell aspiration
Solution Approach 2:
The delivery pump is designed to give a margin to the control values, creating a buffer that prevents radical speed changes. This cushioning effect ensures that even when the controller outputs linear control values, the actual feed speed changes gradually, maintaining stability and preventing waste fluid ruffling and cell aspiration
3Productivity
If the delivery pump operates at high feed speed to complete fluid transfer quickly, then productivity is improved, but contamination risk increases when waste fluid remaining amount is small
Solution Approach 1:
The feed speed is dynamically adjusted based on real-time monitoring of waste fluid remaining amount. During most of the transfer process when waste fluid level is high, the pump operates at high speed for productivity. When waste fluid level drops below a threshold and contamination risk increases, the pump automatically transitions to low-speed operation, thus achieving both high productivity and reliable contamination prevention
Solution Approach 2:
The controller continuously monitors waste fluid remaining amount and provides feedback control to the delivery pump. This feedback mechanism enables the system to automatically switch between high-speed and low-speed operation modes, optimizing productivity during safe conditions and ensuring reliability when contamination risk arises
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 system effectively prevents contamination and stirring of waste fluids, ensuring a controlled and contamination-free transfer of fluids, even when the remaining amount is small, by providing a margin to the control values and using a closed-system configuration with an air vent filter to manage pressure.
Implementation Method 1
a delivery pump (5) which feeds the fluid into the inside of the delivery channel (3) through compressively deforming the inner diameter in the middle of the delivery channel (3)
Implementation Method 2
incorporating a filter for absorbing fungi, bacteria, and foreign matter
Data Source
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AI summary
To avoid contamination of workspaces by splashing and the like of a waste fluid. A fluid delivery system for delivering a fluid from one container to another container includes: a delivery channel connecting between the one container to the other container; and a delivery pump which feeds the fluid into the delivery channel by compressively deforming inner diameter in the middle of the delivery channel, wherein the delivery channel is a partially elastic configuration that can be compressively deformed by the delivery pump, and also is a closed-system configuration with which the fluid flowing inside thereof is isolated from outside. As described, the delivery pump and the delivery tube or the waste-fluid container are not directly connected but are simply in contact. Therefore, it is possible to prevent splashing and the like of the waste fluid onto a workspace when handling the waste fluid.