Irrigation System Flow Control via Indirect Pumping
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Solution Overview
Problem
Existing irrigation systems for medical use, particularly those used for rectal, transanal, and stomal irrigation, face challenges such as complexity, high cost, difficulty in controlling flow rate with precision, and safety concerns, especially for users with reduced dexterity.
Innovation Solution
An irrigation system that includes a reservoir, a pressure sensor, a catheter, tubing, an electrically operated pump for indirect pumping, an electrically operable valve for precise control of flow, and a controller that estimates the actual flow rate based on pump power consumption and speed, allowing for continuous regulation of the valve to achieve a desired flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indirect pumping is used to simplify operation and reduce cost, then ease of operation and manufacturing cost are improved, but flow rate control precision deteriorates
Solution Approach 1:
The system employs a feedback control mechanism where a flow sensor continuously measures the actual flow rate of irrigation liquid, and the controller adjusts the valve's degree of openness based on this feedback to maintain the desired flow rate. This closed-loop control resolves the contradiction by enabling precise flow rate control in the indirect pumping system without compromising ease of operation.
2Measurement precision
If flow meters with adequate accuracy are used to improve flow rate measurement precision, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system uses a simplified flow sensing approach that captures the essential flow information without requiring complex flow meter infrastructure. The flow sensor provides sufficient measurement precision for control purposes while maintaining system simplicity and portability, effectively creating a functional copy of full flow meter capability with reduced complexity.
3Ease of operation
If the system is made portable with limited size for user convenience, then ease of operation and user independence are improved, but the ability to achieve precise flow control deteriorates
Solution Approach 1:
The system merges multiple functions into a compact portable unit: the pump, valve, flow sensor, and controller are integrated into a single handheld device. This consolidation enables precise flow control capabilities to be maintained while achieving the portability and user independence required for self-administration at home or during travel.
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 accurate control of the output flow rate over a broad range, is cost-effective, easy to use, and safe, particularly for users with reduced dexterity, while eliminating the need for costly flow meters.
Implementation Method 1
an electrically operated pump for pumping air into the reservoir, thereby to indirectly pump irrigation liquid from the reservoir to the catheter through said tubing
Implementation Method 2
a pressure sensor for measuring the pressure in the reservoir
Implementation Method 3
an electrically operable valve operable to continuously control the degree of openness of said fluid communication path between a fully closed state and a fully opened state
Data Source
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AI summary
An irrigation system comprises a reservoir for an irrigating liquid and a pressure sensor for measuring the pressure in the reservoir. A catheter is connected to the reservoir by tubing, providing a fluid communication path between the reservoir and the catheter. An electrically operated pump pumps air into the reservoir to indirectly pump irrigation liquid from the reservoir to the catheter, and an electrically operable valve is operable to continuously control the degree of openness of the fluid communication path between a fully closed state and a fully opened state. Further, a sensor estimates power consumption or speed of the electrically operated pump. A controller estimates an actual flow rate from the reservoir based on the estimation of power consumption and/or speed and continuously regulates the electrically operable valve based on the estimated actual flow rate, thereby adjusting the actual flow rate to the desired flow rate, obtained from a user interface,.