Peristaltic Pump Rotor Occlusion Testing via Pressure Differential
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Solution Overview
Problem
Rotary peristaltic pumps used in dialysis machines face issues with insufficient occlusion of flexible tubing due to deformities, spring fatigue, or environmental factors, leading to inadequate downstream pressure and potential malfunction of the dialysis machine.
Innovation Solution
A method for testing rotor engagement and occlusion in rotary peristaltic pumps using a system comprising a peristaltic pump rotor, pressure sensor, valve, and processor to measure fluid pressure and pressure drops, generating alerts if thresholds are not met, ensuring correct occlusion and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the rollers on the protrusions are designed to occlude the flexible tubing, then downstream pressure is improved, but the system becomes sensitive to deformities, spring fatigue, and environmental factors that reduce occlusion effectiveness
Solution Approach 1:
The patent applies preliminary action by implementing a test method that is performed before the pump is deployed or during maintenance intervals. The method proactively identifies potential occlusion problems by measuring pressure differentials and calculating occlusion effectiveness, allowing corrective action to be taken before actual pump failure occurs. This prevents the contradiction from manifesting during critical operation.
Solution Approach 2:
The patent implements feedback by continuously monitoring the pressure differential across the tubing and calculating an occlusion effectiveness metric. This feedback is compared against threshold values to determine whether the occlusion is sufficient. The system provides real-time information about the state of occlusion, enabling operators to adjust or replace components before reliability deteriorates.
2Reliability
If the flexible tubing becomes less compliant due to low temperatures or fatigue, then the roller cannot correctly occlude the tubing, but increasing the biasing spring force may cause excessive compression
Solution Approach 1:
The patent applies parameter changes by using the pressure differential measurements to calculate an occlusion effectiveness parameter that reflects the actual performance under current conditions. The system adjusts its assessment based on the measured pressure relationship rather than relying on fixed design parameters. This allows the system to account for variations in tubing compliance due to temperature or fatigue without requiring physical adjustment of the spring force.
Solution Approach 2:
The patent replaces the mechanical assessment of occlusion (which would require direct measurement of roller force or tubing compression) with a pressure-based measurement system. By measuring pressure differentials upstream and downstream of the occlusion point, the system indirectly assesses occlusion effectiveness without requiring mechanical modification or direct force measurement, thus avoiding the need to increase spring force.
3Reliability
If a deformity in the outer race prevents complete occlusion, then fluid backflow occurs, but replacing the outer race requires disassembly and maintenance downtime
Solution Approach 1:
The patent applies preliminary action by detecting occlusion defects through pressure differential measurements before they lead to fluid backflow and pump failure. The system identifies deformities in the outer race or other occlusion problems during normal operation or preventive maintenance, allowing scheduled replacement of components rather than emergency repairs after failure occurs.
Solution Approach 2:
The patent introduces pressure sensors as intermediary measurement devices that indirectly detect the state of occlusion and the condition of the outer race. Rather than requiring direct inspection or disassembly to detect deformities, the pressure measurements serve as an intermediary indicator of occlusion completeness, enabling non-invasive monitoring and early warning of problems.
4Stress or pressure
If the flexible tubing splits or leaks, then pressure downstream drops, but replacing the tubing requires system shutdown and reassembly
Solution Approach 1:
The patent applies preliminary action by detecting tubing leaks or splits through pressure differential measurements before they cause significant pressure drops or complete pump failure. The system identifies tubing degradation early, allowing scheduled replacement during planned maintenance windows rather than unplanned shutdowns caused by sudden failures.
Solution Approach 2:
The patent implements feedback by continuously monitoring pressure differentials that indicate the integrity of the tubing. When the pressure relationship deviates from expected values, the system generates an alert indicating potential tubing failure. This feedback enables operators to replace tubing proactively before it causes system shutdown, maintaining higher overall availability.
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 method ensures accurate testing of occlusion and operation of rotary peristaltic pumps, preventing malfunctions and maintaining proper pressure in dialysis machines by identifying and addressing occlusion issues.
Implementation Method 1
a pressure sensor arranged to sense the fluid pressure in the tube at a position downstream of the peristaltic pump rotor and upstream of the valve
Implementation Method 2
Rotary peristaltic pumps are a common type of positive displacement pump used for pumping a variety of fluids. The fluid is pumped by subjecting a flexible tube arranged in a race to a series of successive compressions which act to drive the fluid along the tube.
Implementation Method 3
the protrusions of the rotor compress a portion of tubing and move along the tubing squeezing the contained fluid along
Implementation Method 4
the protrusion is moveable relative to the rotor and is biased away from the drive axis of rotation of the rotor by a spring
Data Source
AI summary
A method of testing the rotor engagement of a peristaltic pump rotor. The method comprising steps of providing a pump system comprising a peristaltic pump rotor; a tube; a valve; a pressure sensor; a comparator; and a processor. The pressure sensor is configured to monitor the pressure in a fluid in the tube downstream of the peristaltic pump rotor and upstream of the valve. The comparator is configured to continuously monitor the pressure sensor and compare the measured fluid pressure data with a predetermined parameter. The processor is configured to receive a signal from the comparator and generate an alert signal when the measured pressure data falls outside the predetermined parameters.