Dialysis Machine Pump Energy Control for Flow Continuity
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Solution Overview
Problem
Existing dialysis machines face challenges in maintaining a continuous dialysate volume flow due to the use of discontinuous pumps, leading to inaccuracies in pressure monitoring and increased energy consumption, particularly during occlusions or when the patient is 'emptied', which can result in exceeding the maximum allowable patient pressure limit.
Innovation Solution
The dialysis machine sets a constant energy for each pump stroke based on the pumping time volume and delivered volume, allowing for precise control of the dialysate flow, which adapts to system changes and prevents pressure exceedance by stopping the pumps when limits are reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If discontinuous pumps are used to pump dialysate, then the dialysis machine can operate with simple pump structure, but the dialysate volume flow becomes discontinuous and pressure monitoring becomes inaccurate
Solution Approach 1:
The patent implements a feedback mechanism where the actual dialysate volume delivered by the discontinuous pump is continuously measured and used to calculate and adjust the driving pressure in real-time. This compensation ensures accurate pressure monitoring despite the discontinuous nature of the pump operation, resolving the contradiction between simple pump structure and reliable pressure monitoring.
2Device complexity
If discontinuous pumps operate with acceleration and deceleration phases, then the pump structure remains simple, but the dialysate volume flow varies during ramping phases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the relationship between pump position, velocity, and dialysate volume in lookup tables before operation. During runtime, the controller uses these pre-computed data to determine the exact volume delivered during acceleration and deceleration phases, enabling continuous and accurate volume flow control without complex real-time calculations.
3Device complexity
If the pump delivers variable volume flow during acceleration and deceleration, then the pump operation remains simple, but the energy consumption increases when occlusions occur or patient is emptied
Solution Approach 1:
The patent implements dynamic energy management by continuously adapting the pump driving pressure based on real-time feedback from volume measurements and system resistance detection. When occlusions or empty patient conditions are detected, the controller dynamically reduces the driving pressure to avoid excessive energy consumption, while maintaining simple pump hardware through intelligent control algorithms.
4Device complexity
If constant energy is set for each pump stroke based on pumping time volume and delivered volume, then the control system requirements are simplified, but the system must adapt to system changes
Solution Approach 1:
The patent uses parameter changes by storing multiple sets of pump operation parameters (pressure, volume, time relationships) in lookup tables that can be selected and adjusted based on detected system conditions. This allows the simple constant-energy control approach to adapt to changing system characteristics such as different patient conditions, occlusions, or varying dialysate viscosities, maintaining both simplicity and adaptability.
Data Source
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AI summary
The invention relates to a method for setting a continuous dialysate volume flow rate in a dialysis machine having at least two discontinuous pumps and a control system for producing a desired volume flow rate of the dialysate. According to the invention, in order to produce the most continuous possible dialysate volume flow rate having high constancy, the power for driving the pumps is set to be constant with a value corresponding to the pump-time volume of the respective pump and the required volume. The invention also relates to a dialysis machine for carrying out the aforementioned method.