Peristaltic Pump Temperature Compensation for Stable Solvent Delivery
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Solution Overview
Problem
Peristaltic pumps experience variations in volumetric flow rate due to changes in ambient temperature, leading to inconsistent wash solvent consumption in chromatography systems, which can cause premature depletion or increased wear on seals and plungers.
Innovation Solution
A method and system that regulate the peristaltic pump's motor speed and operation duration based on ambient temperature, using a temperature sensor, processor, and memory module to maintain consistent volumetric delivery by employing a predetermined correspondence of motor speed to temperature, thereby compensating for temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If peristaltic pump operates at constant motor speed, then pump structure is simple, but volumetric flow rate varies with temperature
Solution Approach 1:
The patent applies parameter changes by adjusting the motor speed based on ambient temperature to compensate for tubing expansion/contraction. The controller modifies operational parameters (motor speed) in response to temperature changes, ensuring consistent volumetric flow rate despite temperature variations affecting tubing dimensions.
Solution Approach 2:
The patent implements feedback control by using a temperature sensor to monitor ambient temperature and feeding this information back to the controller. The controller then adjusts the motor speed accordingly, creating a closed-loop system that maintains consistent volumetric flow rate despite temperature fluctuations.
2Reliability
If peristaltic pump delivers more wash solvent, then seal protection is improved, but wash solvent depletion occurs faster
Solution Approach 1:
The patent uses parameter changes to adjust motor speed based on temperature, which directly controls the volumetric flow rate of wash solvent delivery. By optimizing this parameter, the system delivers the precise amount of solvent needed for seal protection without excessive consumption that would lead to premature depletion.
Solution Approach 2:
The patent replaces the mechanical/diaphragm pump system with a peristaltic pump system that offers more precise control over fluid delivery. This substitution enables better regulation of wash solvent flow rate, balancing seal protection needs with solvent conservation.
3Loss of substance
If peristaltic pump delivers less wash solvent, then wash solvent conservation is improved, but seal wear increases
Solution Approach 1:
The patent adjusts motor speed parameters in response to temperature changes to maintain optimal wash solvent delivery. This ensures sufficient solvent reaches the seals for protection and lubrication, preventing increased wear that would result from insufficient delivery, while avoiding wasteful over-delivery.
4Productivity
If peristaltic pump motor speed increases, then volumetric flow rate increases, but temperature compensation complexity increases
Solution Approach 1:
The patent changes motor speed parameters based on temperature to maintain consistent volumetric flow rate. Although this adds control complexity, it enables the system to deliver accurate volumes across varying temperatures, improving overall productivity and reliability.
Solution Approach 2:
The patent implements a feedback control system using temperature sensors and controllers to automatically adjust motor speed. This feedback mechanism manages the complexity by automating the temperature compensation process, allowing the system to maintain high productivity without manual intervention.
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
Ensures accurate and consistent wash solvent delivery, reducing the risk of premature depletion or excessive consumption, and minimizing wear on seals and plungers by maintaining a stable volumetric flow rate regardless of temperature changes.
Implementation Method 1
The volumetric flow rate of a peristaltic pump is dependent on the peristaltic tubing dimensions, motor operating speed, and tubing mechanical properties.
Implementation Method 2
sensing an ambient temperature of a peristaltic pump having a pump motor
Implementation Method 3
One of a motor speed and a motor operation duration is determined for the pump motor based on the sensed ambient temperature, a selected volume of liquid to deliver and a predetermined correspondence of the motor speed to the ambient temperature
Data Source
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Figure 3A
AI summary
A method for regulating a volume of liquid delivered by a peristaltic pump includes: sensing an ambient temperature of the peristaltic pump (220), determining at least one of a motor speed and a motor operation duration based on the sensed ambient temperature (230), and operating the pump motor at a determined motor speed or motor operation duration to deliver a selected volume of liquid from the peristaltic pump (240). A peristaltic pump system with the necessary structural features to perform this method is also disclosed.