Compressible Fluid Pumping System with Segmented Metering
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Solution Overview
Problem
Current high-pressure pumping systems face challenges in accurately metering compressible fluids due to fluid compressibility, leading to flow pulsations and inefficiencies, particularly in applications like high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC), where compressibility variations affect the quality and precision of the process stream.
Innovation Solution
The solution involves separating the thermodynamic work of compression from the metering function using two distinct pumping stages, where a primary booster pump operates in a pressure-controlled mode to pre-compress and thermally condition the fluid, allowing a secondary metering pump to deliver precise, pulse-free flow with minimal thermal and density changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump performs both compression and metering functions, then device complexity is reduced, but metering precision deteriorates due to fluid compressibility and thermal effects
Solution Approach 1:
The pump system is divided into two distinct stages: a first pump dedicated to compression and a second pump dedicated to metering. This segmentation allows each pump to be optimized for its specific function, with the compression pump handling high-pressure generation and the metering pump ensuring precise flow delivery, thereby resolving the contradiction between system simplicity and metering accuracy.
Solution Approach 2:
A thermal conditioning device is introduced as an intermediary component between the compression pump and metering pump. This device removes excess heat generated during compression, preventing thermal expansion and density changes that would compromise metering precision. The intermediary thermal conditioning step enables the metering pump to operate with accurate volumetric displacement without being affected by compression-induced thermal effects.
2Productivity
If compression is performed rapidly to improve productivity, then flow rate increases, but thermal effects and density changes increase reducing metering accuracy
Solution Approach 1:
By separating compression and metering into distinct pumps operating at different rates, the system can perform rapid compression (high productivity) followed by controlled metering (high precision). The compression pump operates independently at high speed to generate pressure, while the metering pump operates at a controlled rate to ensure accurate flow delivery, resolving the contradiction between productivity and precision.
Solution Approach 2:
The compression pump performs preliminary compression of the fluid before it enters the metering pump. This preliminary action prepares the fluid at the required pressure level, allowing the metering pump to focus solely on precise volumetric delivery without needing to perform rapid compression, thereby maintaining both productivity and metering accuracy.
3Loss of energy
If high pressure is applied to compressible fluids, then pumping efficiency improves, but pulsations and flow quality deteriorate
Solution Approach 1:
The two-pump system segments the high-pressure generation from the flow delivery function. The first pump generates high pressure efficiently through compression, while the second pump delivers the fluid with stable, pulse-free flow. This segmentation allows the system to achieve both pumping efficiency and flow quality that would be contradictory in a single-pump system.
Solution Approach 2:
The thermal conditioning device acts as an intermediary that stabilizes the fluid properties between compression and metering. By removing excess heat and preventing density fluctuations, it ensures that the fluid enters the metering pump in a stable state, maintaining flow quality even under high-pressure conditions.
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 enables precise metering of compressible fluids with low pulsation and high accuracy, even for highly compressible fluids like CO2, improving the overall quality and reliability of the process stream, and extends the operational range of existing pumping systems to higher pressures.
Implementation Method 1
a first pump compressing a compressible fluid to a first pressure
Implementation Method 2
a thermal conditioning device removing thermal energy from the compressed fluid to a defined temperature
Implementation Method 3
a second pump metering the thermally conditioned fluid at a controlled rate
Implementation Method 4
wherein the series connection increases a pressure of the compressible fluid to a second pressure higher than the first pressure
Data Source
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AI summary
An invention is claimed that enables the pumping of compressible fluids at high pressures when an accurate flow is desired. Two pressure sources, for example pumps plumbed in series, separate thermodynamic work, such as pressurization, at the first pressure source from a volumetric or matter metering function in the second pressure source. One example is a flowstream delivery for a chemical instrumentation system that is manufactured from relatively unsophisticated pumps yet delivers precise flows with low pulsation (<1%) over pressures greater than 100 bar. An advantage of one embodiment allows the economical conversion of typical HPLC systems to state of-the-art supercritical fluid chromatography (SFC) systems with minimal modification to system components.