Variable Angle Peristaltic Pump Rollers for Dialysis
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Solution Overview
Problem
Dialysis machines often experience undesirable pulsations and blood cell destruction (hemolysis) due to pressure fluctuations during the fluid pumping process, as the peristaltic pump's pinch elements position at a fixed angle, causing pressure differences that lead to fluid backflow and cell damage.
Innovation Solution
The peristaltic pump design features angularly positionable pinch elements relative to each other, allowing for pre-compression of the fluid volume, minimizing pressure fluctuations by adjusting the angle between pinch elements to match the pressure difference, and using a control device to manage this positioning based on pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peristaltic pump uses fixed-angle squeezing elements, then the pump structure is simple and reliable, but pressure fluctuations occur causing pulsation and hemolysis
Solution Approach 1:
The patent applies the dynamics principle by making the angular positioning of the squeezing elements variable rather than fixed. The control device adjusts the angular positions dynamically based on operating conditions, allowing the pump to adapt to different flow rates and pressure requirements, thereby eliminating pulsation and hemolysis while maintaining operational stability
Solution Approach 2:
The patent changes the angular position parameter of the squeezing elements to optimize pump performance. By varying the angular positions according to the relationship between rotational speed and angle, the system achieves smooth pressure transfer and eliminates the harmful pulsation effects without sacrificing reliability
2Device complexity
If the squeezing elements are positioned at a fixed 180° angle, then the device complexity is low, but pressure equalization causes fluid backflow and blood cell destruction
Solution Approach 1:
The patent transforms the static 180° fixed positioning into a dynamic variable-angle system. The angular positions of the squeezing elements are adjusted based on rotational speed and pressure conditions, preventing pressure equalization that would cause backflow and hemolysis, while the control device manages this complexity automatically
Solution Approach 2:
The control device implements feedback control by monitoring the rotational speed and angular positions of the squeezing elements, and automatically adjusting the positioning to maintain optimal pressure differential, thereby preventing fluid backflow and blood cell destruction
3Power
If the peristaltic pump operates with rigid pressure transfer, then the pumping action is strong and efficient, but pulsation occurs on the high-pressure side
Solution Approach 1:
The patent changes the pressure transfer parameter from rigid to variable by adjusting the angular positions of the squeezing elements. This allows the pump to maintain strong pumping action while smoothing out pressure fluctuations, achieving both high power efficiency and pressure stability
Solution Approach 2:
The control device performs preliminary adjustment of the squeezing element angles before pressure fluctuations can occur. By proactively optimizing the angular positions based on rotational speed, the system prevents pulsation while maintaining efficient pumping
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 design reduces or eliminates pulsations and hemolysis by ensuring consistent pressure transfer, minimizing fluid backflow, and maintaining optimal pressure conditions, thereby enhancing the efficiency and safety of blood treatment in dialysis machines.
Implementation Method 1
an elastically deformable fluid line arranged between the low-pressure side and the high-pressure side is deformed between a support surface and a rotor rotating relative to it with at least two squeezing elements
Implementation Method 2
The peristaltic pump of such a system has the task of pumping a defined volume of a medium, such as blood or dialysis fluid, by deforming and clamping the elastically deformable fluid line
Implementation Method 3
the squeezing elements are angularly positioned relative to each other during the rotation of the rotor to effect pre-compression
Data Source
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AI summary
The invention relates to a method for conveying fluid in a device for extracorporeal blood treatment, wherein fluid is conveyed from a low-pressure side to a high-pressure side by means of a peristaltic pump 2, wherein an elastically deformable fluid line 31 arranged between the low-pressure side and the high-pressure side is deformed between a support surface 33 and a rotor 23 rotating relative to it with at least two squeezing elements 27, 28, wherein the squeezing elements 27, 28 are angularly positioned relative to each other during the rotation of the rotor 23 to effect a pre-compression.It further relates to a dialysis machine with a peristaltic pump 2 conveying fluid from a low-pressure side to a high-pressure side, wherein the peristaltic pump 2 is configured to accommodate an elastically deformable fluid line 31 between the low-pressure side and the high-pressure side, and has a support surface 33 supporting the fluid line 31 and a rotor 23, wherein the rotor 23 has at least two squeezing elements 27, 28 each deforming the fluid line 31 between itself and the support surface 33, wherein the squeezing elements 27, 28 are designed to be angularly positionable relative to each other in the direction of rotation.