Rotary Valve Fluid Delivery with Piston Segmentation
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Solution Overview
Problem
Existing medical fluid delivery systems face challenges in maintaining flow rate accuracy regardless of system positioning and require complex priming processes that result in fluid wastage.
Innovation Solution
A method utilizing a rotary valve with priming and pumping positions, coupled with an external electromechanical pump, which allows for precise fluid transfer between an inlet and outlet tube through reciprocating movement of a piston, ensuring accurate volume delivery and independent of system elevation changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a push valve mechanism is used to occlude flow by pressing on a membrane, then fluid delivery is achieved, but volumetric delivery precision deteriorates and flow rate varies by up to 20% based on system elevation
Solution Approach 1:
The pump chamber is divided into multiple segments or chambers that work in sequence, with each chamber contributing to a controlled portion of the total fluid delivery. This segmentation allows for more precise control of volumetric delivery by isolating the function of each chamber and reducing the impact of elevation changes on the overall system.
Solution Approach 2:
The invention replaces the elastic membrane-based push valve mechanism with a rigid valve system that uses mechanical positioning and sealing surfaces to control flow occlusion. This substitution eliminates the compliance and elasticity effects that cause volumetric imprecision in membrane-based systems, providing more accurate and consistent fluid delivery regardless of elevation changes.
2Ease of operation
If a rotary valve system is used to sequester and deliver fluid, then flow direction control is achieved, but priming requires fluid wastage to expel air from channels
Solution Approach 1:
The system incorporates a priming mode that is activated before normal operation begins. During this preliminary action phase, the valve is positioned to allow air evacuation from the fluid channels without delivering fluid to the patient. Once priming is complete and air is removed, the valve transitions to the pumping position, preventing fluid wastage during the priming process.
Solution Approach 2:
The valve system is designed with dynamic positioning capability that allows it to transition between different operational modes (priming mode and pumping mode). This dynamic behavior enables the system to optimize its function for each phase of operation, allowing air evacuation during priming without fluid delivery, and precise fluid delivery during pumping, thereby eliminating unnecessary fluid wastage.
3Ease of operation
If a push valve system is used, then fluid occlusion is achieved, but the system becomes sensitive to elevation changes of pump, reservoir and patient
Solution Approach 1:
The invention replaces the elastic membrane-based occlusion mechanism with a rigid valve system that uses mechanical sealing surfaces and positive displacement principles. This substitution creates a flow control mechanism that is insensitive to elevation changes, as the rigid components maintain their geometric relationships and sealing effectiveness regardless of gravitational effects on the fluid column.
Solution Approach 2:
The valve system is designed to perform multiple functions: it provides flow occlusion, directs fluid flow between different channels, controls priming operations, and maintains consistent delivery across varying elevations. This multi-functionality is achieved through a unified mechanical design that integrates these capabilities into a single robust system, improving reliability across different operating conditions.
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 solution achieves high flow rate accuracy and efficient priming without fluid wastage, maintaining consistent fluid delivery regardless of system positioning and reducing pulsation, thereby improving the reliability of medical fluid delivery systems.
Implementation Method 1
moving, during the inflow phase, a first piston (38) coupled with the first aspiration cavity (24) to increase the volume of the first aspiration cavity (24)
Implementation Method 2
moving, during the outflow phase, the first piston (38) to decrease the volume of the first aspiration cavity (24)
Data Source
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AI summary
An apparatus for delivery of fluids to a patient includes an inlet tube (102) and an outlet tube (104) connected to each other at an angular joint. A rotary valve (108) and a piston (122) are fitted to the angular joint forming a chamber (120). The rotary valve (108) is provided with a wedge shaped opening (112) and a priming tubule (114). For priming operation with the fluid delivery apparatus, a user sets the rotary valve to a priming position. During pumping operation, the rotary valve rotates in coordination with the piston (122) to transfer a quantum of fluid from the inlet tube (102) to the outlet tube (104) via the chambe (120)r. A second piston (402) is provided on the outlet tube (104) for smoothing out flow rate pulsations.