Blood Purification Device Priming Circuit and Pump Control
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Solution Overview
Problem
Current blood purification devices face challenges in priming due to the limitations of water removing pumps with low flow rates and high accuracy, and dialysate supply pumps with high flow rates and low accuracy, which can lead to prolonged priming times and potential membrane damage.
Innovation Solution
A blood purification device with a fluid replacement/priming circuit that includes a bypass circuit and a connection circuit, allowing for selective connection to the dialysate supply and discharge circuits, and equipped with flow rate adjusting units and a reversible fluid replacement pump, enabling controlled dialysate flow through the blood purification membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If water removing pump is used for supplying dialysate to blood circuit in priming, then flow rate accuracy is improved, but priming time is prolonged
Solution Approach 1:
The water removing pump is designed to perform multiple functions: both water removal during blood purification and dialysate supply during priming. By making the pump multi-functional, the system avoids using a separate pump for priming, thereby reducing device complexity while maintaining flow rate accuracy. The pump's capability to operate in reverse direction enables it to supply dialysate to the blood circuit effectively.
Solution Approach 2:
The system dynamically changes the operating mode of the water removing pump based on the treatment phase. During priming, the pump operates in reverse to supply dialysate; during blood purification, it operates in forward mode to remove water. This dynamic operation allows the same pump to meet different flow rate requirements at different times, resolving the contradiction between accuracy and time.
2Loss of time
If dialysate supply pump is used for supplying dialysate to blood circuit in priming, then priming time is reduced, but blood purification membrane may be damaged
Solution Approach 1:
The system changes the flow rate parameter dynamically based on the operational phase. During priming, the water removing pump operates at higher flow rates to complete priming quickly; during blood purification, the flow rate is reduced to safe levels that protect the membrane. This parameter adjustment resolves the contradiction between speed and safety.
Solution Approach 2:
The pump operates in reverse direction during priming to supply dialysate at high flow rates, then switches to forward direction during blood purification to maintain safe flow rates. This dynamic directional change allows the system to achieve both fast priming and membrane protection without requiring separate pumps.
3Loss of time
If water removing pump operates at maximum flow rate during priming, then priming time is reduced, but pump load increases causing degradation
Solution Approach 1:
Instead of operating the water removing pump in its normal forward direction at maximum speed (which would cause degradation), the system reverses the pump's rotation direction during priming. This reverse operation allows the pump to handle high flow rates without the mechanical stress and degradation associated with high-speed forward operation, thereby reducing priming time while preserving pump longevity.
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 configuration allows for efficient and accurate priming by adjusting flow rates to suit the process, reducing the risk of membrane damage and optimizing the priming time, while also enabling fluid replacement and urgent fluid supply.
Implementation Method 1
blood passes through a primary side of the blood purification membrane and the dialysate passes through a secondary side of the blood purification membrane so that unwanted components in the blood are taken into the dialysate through the blood purification membrane
Implementation Method 2
fresh dialysate in the dialysate circuit is supplied to a blood circuit to perform fluid replacement on the patient
Data Source
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AI summary
Priming and fluid replacement of a blood purification device is suitably performed by using a pump having a flow rate and a flow rate accuracy suitable for priming. The blood purification device includes: a blood purification unit (20) having a blood purification membrane (30); a blood circuit (10) that feeds blood in a blood collection part (21) to a primary side of the blood purification membrane (30) and returns the blood from the primary side to a blood return part (23) by using a blood pump (40); a dialysate supply circuit (91) that supplies the dialysate to a secondary side of the blood purification membrane (30); a dialysate discharge circuit (92) that discharges the dialysate from the secondary side; and a fluid replacement/priming circuit. While the blood collection part (21) and the blood return part (23) are connected to each other to form a loop shape of the blood circuit (10), the dialysate in the dialysate supply circuit (91) is supplied to the primary side through the blood purification membrane (30) by using a fluid replacement pump (170), and the dialysate in the blood circuit (10) including the primary side is discharged to the dialysate discharge circuit (92) without passing through the blood purification membrane (30) by using a fluid replacement pump (170).