Peritoneal Dialysis Pump Position Detection Through Pressure Feedback
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Solution Overview
Problem
Existing automated peritoneal dialysis systems require complex components that need calibration and maintenance, increasing costs and reducing portability and ease of use.
Innovation Solution
A peritoneal dialysis system with a PD machine that includes a piston pump with integrated pressure sensors and a control unit to determine the pump actuator position using pressure feedback, eliminating the need for dedicated position sensors and simplifying component maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated position sensors are added to the pump actuator, then motor angular position accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses fluid pressure as an intermediary to indirectly measure pump actuator position. Instead of directly sensing motor angle with complex sensors, the system measures pressure changes in the fluid line that correspond to pump piston position, thereby determining motor angular position through a simpler pressure measurement intermediary.
Solution Approach 2:
The patent replaces the mechanical/electrical position sensing system (encoders, resolvers, or other angular sensors) with a fluid-based pressure sensing system. The pressure sensor detects fluid pressure variations that occur at specific points in the pump cycle, substituting complex mechanical position measurement with simpler fluid pressure measurement.
2Measurement precision
If more sensors are added to the system, then measurement accuracy is improved, but ease of manufacture and maintenance worsen
Solution Approach 1:
The patent makes the existing pressure sensor serve multiple functions: it continues to monitor fluid pressure for therapeutic control while simultaneously providing pump actuator position information. This multi-functionality eliminates the need for additional dedicated position sensors, simplifying manufacturing and reducing component count.
Solution Approach 2:
The system uses its existing pressure sensing capability to serve the additional function of position detection. The pressure sensor essentially 'self-services' by providing dual information (pressure control and position feedback) without requiring external additional sensors, thereby simplifying the overall system.
3Ease of operation
If the system uses simpler components without dedicated position sensors, then ease of operation and maintenance are improved, but measurement precision of pump position may worsen
Solution Approach 1:
The patent implements feedback by continuously monitoring fluid pressure and using these readings to determine pump actuator position in real-time. The control system receives pressure feedback and uses it to infer motor angular position, creating a closed-loop system that maintains precision without complex hardware.
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 accurately determines the pump actuator position, reducing the need for additional sensors, improving motor angular position accuracy, and enhancing fluid volume control, thereby simplifying setup and maintenance while maintaining therapeutic efficacy.
Implementation Method 1
a pump actuator position sensor or other pump position indicator can be used to indicate a position of the motor
Data Source
AI summary
A peritoneal dialysis (“PD”) system includes a PD fluid pump including a reciprocating member having a home position; at least one pressure sensor positioned and arranged to sense pressure PD fluid pumped by the PD fluid pump; and a control unit configured to control the PD fluid pump and to take PD fluid pressure readings from the at least one pressure sensor, the control unit further configured to use the PD fluid pressure readings to determine when the reciprocating member is in the home position, and to stop the PD fluid pump when the reciprocating member is in the home position.