Hemodialysis Fluid Replacement Pump Flow Rate Calibration
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Solution Overview
Problem
Existing hemodialysis systems face challenges in accurately calibrating the flow rate of fluid replacement pumps without incurring increased costs or labor, particularly due to the reliance on weighing containers for fluid replacement rate detection.
Innovation Solution
A calibration device that operates the dialysate and fluid replacement pumps in specific sequences to calculate and adjust the flow rate of the fluid replacement pump, using the total and remaining discharge times to ensure accurate calibration without the need for costly weighing containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a weighing container is used to detect fluid replacement rate, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The dialysate pump's flow meter is made to serve dual purposes: monitoring dialysate flow rate during dialysis and measuring fluid replacement rate during fluid replacement. This eliminates the need for separate weighing containers while maintaining measurement accuracy.
Solution Approach 2:
The patent combines the dialysate circulation system and fluid replacement system into a single integrated setup where the dialysate pump and its flow meter are shared between both functions. The flow meter becomes a multi-functional measurement device that tracks both dialysate flow and fluid replacement volume.
2Measurement precision
If a weighing container is used for fluid replacement detection, then measurement precision is improved, but labor in cleaning increases
Solution Approach 1:
The dialysate pump and flow meter are designed to perform both dialysate circulation and fluid replacement measurement functions, eliminating separate weighing containers that would require additional cleaning procedures.
Solution Approach 2:
The system uses existing components (dialysate pump and flow meter) that are already part of the dialysis circuit, making them self-sufficient for dual purposes without requiring separate maintenance or cleaning of additional devices.
3Device complexity
If flow rate calibration is performed using existing dialysate pump, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The system uses the flow meter to continuously monitor actual flow rates during calibration operations, providing feedback to the control unit which then adjusts pump settings to achieve precise calibration without requiring complex external equipment.
Data Source
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AI summary
A controller C executes a first operation of operating a dialysate pump 27 at a predetermined set flow rate, to obtain total discharge time until dialysate supplied to fill a supply chamber 21a of a dialysate chamber 21 runs out. Next, the controller executes a second operation of operating a fluid replacement pump 19 at a predetermined set flow rate only for predetermined time, to discharge a part of the dialysate supplied to fill the supply chamber 21a, and next executes a third operation of operating the dialysate pump 27 at the same set flow rate as in the first operation again, to obtain remaining discharge time until residual dialysate remaining in the supply chamber runs out after the end of the second operation. A substantial flow rate of the fluid replacement pump can be calculated from the total discharge time and the remaining discharge time, and hence in a calibrating operation of the fluid replacement pump, the controller adjusts setting of the fluid replacement pump to eliminate a difference between the set flow rate and the substantial flow rate in the fluid replacement pump. The flow rate of the fluid replacement pump 19 can be calibrated without adding any special configuration.