Automated Fluid Flow Control with Closed-Loop Resistance Adjustment
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Solution Overview
Problem
Current intravenous infusion methods lack precision and flexibility in controlling flow rates, are prone to human error, and often require complex and costly equipment, which can lead to safety issues such as 'runaway infusion' and air infusion hazards.
Innovation Solution
A fluid administration system with a closed-loop quasi-static adjustment of in-line pressure-based resistance, using a fluid pathway assembly and flow control device that includes a bi-directional flow measurement device and variable resistance, allowing for precise control of fluid flow rates through a combination of manual and servomechanism regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual flow control by adjusting resistance is used, then the system remains simple and portable, but flow rate precision and control accuracy deteriorate
Solution Approach 1:
The patent implements a closed-loop feedback control system where a flow sensor continuously monitors the actual flow rate and feeds this information back to a controller. The controller compares the measured flow rate with the target flow rate and automatically adjusts the resistance mechanism to maintain precise flow control, thereby resolving the contradiction between system simplicity and flow rate precision.
Solution Approach 2:
The patent replaces manual mechanical flow control with an automated electromechanical system. A motor-driven mechanism adjusts the resistance based on electronic control signals, eliminating the need for manual observation and adjustment while maintaining system portability. This substitution of mechanical manual control with automated electromechanical control achieves both precision and relative simplicity.
2Measurement precision
If positive displacement pumps are used for precise flow control, then flow rate precision improves, but device complexity, size, and cost increase
Solution Approach 1:
The patent employs a dynamic resistance adjustment mechanism controlled by a motor and feedback system, replacing the static, complex positive displacement pump structure. The dynamic control of resistance allows precise flow rate adjustment without the mechanical complexity of piston or peristaltic pumping mechanisms, achieving flow precision while reducing device complexity and size.
Solution Approach 2:
The patent extracts the flow control function from the complex positive displacement pump structure and implements it separately through a simple resistance mechanism controlled by an automated system. This separation allows precise flow control to be achieved without incorporating the bulky and complex pumping mechanisms, thereby reducing overall device complexity while maintaining portability.
3Object-affected harmful factors
If positive displacement pumps with flow stop mechanisms are used, then runaway infusion hazard is reduced, but flow continuity and precision deteriorate
Solution Approach 1:
The closed-loop feedback control system continuously monitors flow rate and automatically adjusts resistance to maintain the target flow rate, preventing runaway infusion through electronic control rather than mechanical flow stop mechanisms. This feedback-based approach maintains flow continuity and precision while eliminating the need for abrupt flow cessation, thereby preserving reliability.
Solution Approach 2:
The system incorporates safety features such as air detection sensors and automated resistance adjustment that prevent hazardous conditions before they occur. The feedback control anticipates potential flow deviations and corrects them proactively, cushioning against runaway infusion risks without requiring abrupt flow stops that would compromise flow continuity.
4Object-affected harmful factors
If air detection systems are incorporated in positive displacement pumps, then air infusion hazard is reduced, but device complexity and cost increase
Solution Approach 1:
The patent integrates air detection functionality into the existing flow sensor and control system, allowing the same sensing infrastructure to serve multiple purposes including flow rate measurement and air bubble detection. This multi-functional approach reduces overall system complexity compared to adding separate dedicated air detection systems to positive displacement pumps, while still providing protection against air infusion hazards.
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 provides precise and flexible control of fluid flow rates, reducing the risk of safety hazards and improving operator efficiency, while maintaining simplicity and portability, suitable for moderate infusion needs without the complexity and cost of traditional positive displacement pumps.
Implementation Method 1
an in-line rotary flow impeller
Implementation Method 2
a set of electromagnetic coils which can be used to sense or drive rotation of the magnetic impeller
Implementation Method 3
closed loop quasi-static adjustment of in-line pressure-based resistance
Data Source
AI summary
A device for control of fluid flow with closed loop quasi static adjustment of in-line pressure-based resistance. The disclosed device and methods of using the device provide for the ability to control a flow rate with a highly portable device; the ability for an operator to safely use the device with minimal training; the ability to automatically switch between a primary and secondary fluid; the ability to maintain a flow rate through a tubing set even when the control device is removed; and the ability to measure fluids introduced with a manual bolus injection.