Solenoid Valve Current Profiling for Quiet Dialysis Activation Checks
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Solution Overview
Problem
Solenoid valves used in medical fluid systems, such as automated peritoneal dialysis, suffer from noise issues during operation and uncertainty about valve activation status, which can disrupt patient care and treatment efficacy.
Innovation Solution
The implementation of a control unit with NPN transistors, MOSFETs, and pulse width modulation (PWM) to slow down the movement of solenoid valve plungers, reduce noise, and assess valve activation status through current profile analysis and polynomial modeling, ensuring proper valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If solenoid valves are used to control medical fluid flow, then valve activation speed is improved, but noise levels increase and activation status becomes uncertain
Solution Approach 1:
The patent introduces an intermediary assessment mechanism that measures current draw characteristics of the solenoid valve coil to determine activation status. This intermediary measurement approach allows verification of valve activation without directly observing the mechanical plunger movement, thereby maintaining fast activation speed while providing reliable status confirmation and reducing noise-related uncertainties
Solution Approach 2:
The patent replaces direct mechanical observation of plunger movement with an electrical measurement system that monitors current draw characteristics. By substituting mechanical status detection with electrical parameter analysis, the system maintains rapid valve response while eliminating the need for noisy mechanical indicators or slow mechanical feedback mechanisms
2Speed
If solenoid valves are used to control medical fluid flow, then valve activation speed is improved, but reliability of activation status decreases
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors the current draw characteristics of the solenoid valve coil during activation. By measuring and analyzing the electrical parameters (current magnitude, duration, and temporal profile), the system provides reliable feedback confirmation of valve activation status, ensuring that the fast-acting solenoid valve operates reliably without status uncertainty
3Productivity
If fast-acting solenoid valves are used, then treatment efficiency is improved, but noise disruption to patient care increases
Solution Approach 1:
The patent introduces an intermediary electrical measurement system that assesses valve activation through current draw characteristics rather than direct mechanical monitoring. This intermediary approach maintains the fast-acting performance of solenoid valves for treatment efficiency while eliminating the need for noisy mechanical feedback devices that would disrupt patient care
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 solution effectively reduces noise levels in medical fluid systems, ensures accurate valve activation, and enhances the reliability of solenoid valve operation, improving patient comfort and treatment outcomes.
Implementation Method 1
a coil, and a plunger, wherein the valve is configured to activate a flow of fluid through a tube by applying, via an associated transistor, voltage to the coil to move the plunger within the housing
Data Source
AI summary
Systems and methods are disclosed for assessing the functionality of solenoid valve activation in peritoneal dialysis systems. In at least one embodiment, measurements of current values may be received from a solenoid valve at a predetermined sampling rate over a predetermine duration of time to generate a current profile for the solenoid valve. A fifth degree polynomial model may be fit to the current profile and optimized. The optimized polynomial model may be applied to a trained support vector machine to determine whether the current profile indicates that the corresponding solenoid valve has actually opened or closed.