Peristaltic Pump Occlusion Detection via Dynamic Pressure Thresholds
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Solution Overview
Problem
Existing peristaltic pumps face challenges in reliably detecting fault conditions like occlusions due to inaccurate calibration and system dispersion over time, caused by mechanical wear, temperature changes, and setup modifications, leading to false alarms or missed alerts.
Innovation Solution
A method that computes threshold values directly from measured pressure signals, eliminating the need for initial calibration by deriving first and second signal values indicative of downstream and upstream pressures, which are compared to detect occlusions, with the threshold values updated continuously or at intervals to account for system changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If initial calibration with predetermined threshold values is used to detect occlusions, then the detection method is simple to implement, but the detection accuracy deteriorates over time due to mechanical wear, temperature changes, and system dispersion
Solution Approach 1:
The patent transforms the static threshold value into a dynamic reference pressure signal that automatically adapts to changing system conditions. The reference pressure signal is continuously updated based on the actual operating conditions of the peristaltic pump, including variations in tube characteristics, mechanical wear, and temperature changes. This dynamic adaptation eliminates the need for manual recalibration while maintaining high detection accuracy throughout the system's operational life.
Solution Approach 2:
The patent changes the parameter used for occlusion detection from fixed predetermined threshold values to variable reference pressure signals derived from actual system operation. By using the minimum and maximum pressure signals observed during normal operation as dynamic thresholds, the system automatically adjusts to changing parameters such as tube elasticity, pump wear, and environmental conditions, thereby maintaining reliable detection accuracy.
2Ease of operation
If predetermined threshold values are used for occlusion detection, then the system setup is simple, but false alarms and missed alerts occur due to system dispersion and calibration drift
Solution Approach 1:
The patent implements a self-calibrating system that automatically generates its own reference pressure signals during normal operation. The system uses the minimum and maximum pressure signals observed during operation to dynamically establish detection thresholds, eliminating the need for manual calibration by operators. This self-service approach ensures consistent detection precision without requiring expert setup or periodic recalibration.
Solution Approach 2:
The patent incorporates feedback mechanisms where the actual pressure signals during operation are continuously monitored and used to update the reference pressure signals. The system feeds back information about actual system performance to automatically adjust the occlusion detection thresholds, ensuring that the detection precision remains high even as system conditions change over time.
3Productivity
If fixed threshold values are applied to detect occlusions, then the detection algorithm is computationally simple, but the system cannot adapt to changes in tube characteristics and pump conditions over time
Solution Approach 1:
The patent replaces static threshold comparisons with dynamic reference pressure signal comparisons. The reference pressure signals are continuously updated based on actual operating conditions, allowing the system to adapt to changes in tube characteristics, pump wear, and environmental factors. This dynamic approach maintains computational efficiency while significantly improving system adaptability throughout its operational life.
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 approach allows for accurate and reliable detection of occlusions without requiring calibration, reducing the impact of system dispersion and ensuring consistent performance over the pump's lifetime.
Implementation Method 1
a pressure sensor being arranged between the upstream valve mechanism and the downstream valve mechanism for measuring a pressure signal indicative of a pressure inside the flexible tube
Implementation Method 2
the flexible tube is compressed in a section between the upstream valve mechanism and the downstream valve mechanism such that, by sequential actuation of the compression mechanism, the upstream valve mechanism and the downstream valve mechanism a liquid may be transported along the downstream direction within the flexible tube
Data Source
AI summary
A peristaltic pump comprises a flexible tube, a compression mechanism being actuatable for compressing the flexible tube, an upstream valve mechanism being actuatable to selectively open or close the tube upstream of the compression mechanism and a downstream valve mechanism being actuatable to selectively open or close the tube downstream of the compression mechanism. A drive mechanism actuates the compression mechanism, the upstream and downstream valve mechanisms. A pressure sensor measures a pressure signal indicative of a pressure in the tube between the upstream and downstream valve mechanisms. First and second signal values indicative of a pressure value downstream the downstream valve mechanism and upstream the upstream valve mechanism, respectively, are computed from the measured pressure signal. A threshold value is computed from the first and second signal values, and the measured pressure signal or a derived signal parameter is compared with the threshold value to detect a fault condition.