Bioprocess Valve Control With Variable Closing Force
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Solution Overview
Problem
In bioprocess flow systems, pinch and diaphragm valves often experience issues with internal surfaces sticking together due to material homogenization or material property differences, leading to flow blockages, especially after prolonged closure with high clamping force, which can be problematic in automated systems.
Innovation Solution
Implementing a control system that allows valves to operate in three states: an open state and two closed states with different closing forces, where the higher force is used during fluid flow and a lower force during idle conditions, reducing the risk of surfaces sticking together and preventing flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high closing force is applied to ensure reliable flow stopping, then flow control reliability is improved, but the risk of internal surfaces sticking together increases
Solution Approach 1:
The valve closing force is made dynamic rather than static. The control system adjusts the closing force based on operational conditions: applying higher force during active fluid flow to ensure reliable stopping, and reducing force during idle periods to minimize surface sticking. This dynamic adjustment resolves the contradiction between maintaining reliability and preventing harmful sticking effects.
Solution Approach 2:
The valve implements periodic opening-closing cycles even during idle states. Rather than remaining continuously closed, the valve periodically opens and closes to prevent the internal surfaces from adhering together. This periodic action maintains the valve's ability to open smoothly when needed while still providing flow control when required.
2Reliability
If valve remains closed for extended periods with high clamping force, then flow stopping is maintained, but tube inner surfaces stick together causing flow blockage
Solution Approach 1:
During extended idle periods, the valve performs periodic opening-closing cycles. These periodic actions prevent the tube inner surfaces from sticking together by periodically separating them, ensuring that when flow needs to resume, the valve can open smoothly without blockage while maintaining flow stopping capability when closed.
Solution Approach 2:
The valve applies preliminary opening force before actual flow resumption is needed. By periodically opening the valve during idle periods, the system performs a preliminary action that prevents surface adhesion in advance, ensuring smooth flow restoration when the valve needs to open after extended closure.
3Productivity
If manual intervention is used to resolve sticking issues, then flow blockage can be cleared, but automation is compromised
Solution Approach 1:
The valve system is designed to self-manage the sticking problem through automated periodic opening-closing cycles. The control system automatically detects idle states and initiates preventive opening sequences without manual intervention. This self-service mechanism maintains flow restoration capability while preserving full system automation, eliminating the need for manual tube massaging.
4Reliability
If three-state valve control is implemented, then surface sticking is minimized, but control system complexity increases
Solution Approach 1:
The control system implements a universal state machine that manages all valve operations (open, closed, periodic cycling) through a single integrated controller. This multi-functional approach handles flow control, flow stopping, and preventive opening sequences within one control architecture, minimizing the increase in system complexity while achieving reliable three-state operation.
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 ensures reliable valve operation by minimizing the risk of flow obstruction due to sticking surfaces, allowing for efficient fluid control in bioprocess systems, even after extended periods of inactivity or low fluid pressure, and can be implemented with minimal modifications to existing valve designs.
Implementation Method 1
The opening of the tube is achieved by the elastic properties of the tube and its desire to assume its original shape of an open tube and lumen
Data Source
AI summary
A valve configured to be in a first state, which is an open state when a flow through the tube should be allowed; a second state during some parts of a process run in the system, said second state is a closed state were a first closing force is provided; and a third state during some parts of a process run in the system, said third state is a closed state were a second closing force is provided which is a higher force than the first closing force.