Plunger Pump Thermal Pulsation Compensation
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Solution Overview
Problem
Despite efforts to improve flow rate stability in liquid chromatography, thermal effect pulsation remains a challenge due to heat generation during pre-compression, leading to fluctuations in flow rate and pressure.
Innovation Solution
A liquid feeding apparatus with plunger pumps connected in series or parallel, featuring a control unit that calculates and applies a compensation flow rate to counteract flow rate losses caused by cooling and contraction, based on pressure rise and temperature measurements, ensuring continuous fluid discharge and stable flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-compression process is implemented to achieve continuous fluid discharge, then flow rate stability is improved, but thermal effect pulsation occurs due to heat generation and cooling contraction
Solution Approach 1:
The control unit calculates and applies a compensation flow rate in advance during the discharge process to counteract the flow rate loss that will occur due to cooling and contraction after pre-compression. This preliminary compensation action prevents the thermal effect pulsation from manifesting as actual flow rate instability.
Solution Approach 2:
The system uses pressure rise measurements during pre-compression and temperature measurements to calculate the compensation flow rate. This feedback mechanism continuously monitors the thermal effects and adjusts the compensation accordingly, creating a closed-loop control system that eliminates thermal effect pulsation.
2Device complexity
If plunger pumps operate in intermittent mode, then device complexity is reduced, but flow rate stability deteriorates due to pulsation
Solution Approach 1:
The system implements continuous fluid discharge by coordinating multiple plunger pumps so that while one pump is in suction mode, another is in discharge mode. The control unit calculates compensation flow rates to ensure seamless transition between pumps, eliminating flow rate pulsation and maintaining continuous useful action without increasing device complexity.
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 solution achieves stable flow rates by compensating for thermal effects, reducing pulsation and maintaining flow rate stability even during heat generation in the pre-compression process.
Implementation Method 1
the fluid is compressed and heated in a pre-compression process
Implementation Method 2
cooling and contraction in the discharge process after the fluid in the plunger pump is compressed and heated
Data Source
AI summary
A liquid feeding apparatus includes: a plurality of plunger pumps fluidly connected in series or in parallel between a suction flow path and a discharge flow path; and a control unit configured to control an operation of the plunger pump. The control unit includes a compensation flow rate calculation unit configured to calculate a positive compensation flow rate which changes with time in synchronization with the period with respect to a set flow rate. The compensation flow rate is a flow rate which compensates for a loss of the flow rate caused by cooling and contraction in a discharge stroke after the fluid in the plunger pump is compressed and heated in a pre-compression stroke. The compensation flow rate calculation unit is configured to calculate the compensation flow rate.