Static Back Pressure Regulator for SFC Systems
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Solution Overview
Problem
Supercritical fluid chromatography systems face challenges in maintaining constant back pressure and surviving the corrosive and erosive environment of CO2/co-solvent mixtures, particularly during phase changes and rapid decompression.
Innovation Solution
A static back pressure regulator is designed with a poppet and spring mechanism that includes a calibration element to adjust force, a damping member to absorb energy, and features like helical grooves and chemically resistant materials to inhibit vibration and corrosion, ensuring consistent pressure regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a static back pressure regulator is used to maintain constant back pressure, then pressure stability is improved, but the device must survive corrosive CO2/co-solvent mixtures and rapid decompression which worsens material durability
Solution Approach 1:
The poppet is constructed as a composite structure with a ceramic tip (for chemical resistance) and a metal stem (for mechanical strength). This composite design allows the device to withstand both the corrosive CO2/co-solvent environment and the mechanical stresses of rapid decompression while maintaining stable back pressure regulation
Solution Approach 2:
The spring calibration element allows adjustment of the spring force parameter, enabling optimization of the balance between spring force and fluid pressure. This parameter adjustment capability ensures stable back pressure regulation while accommodating variations in operating conditions and material properties
2Reliability
If the poppet is made of chemically resistant ceramic, then corrosion resistance is improved, but the poppet may tip or vibrate which worsens flow control precision
Solution Approach 1:
The poppet is segmented into two functional parts: a ceramic tip for chemical resistance and sealing, and a metal stem for mechanical guidance and structural support. This segmentation allows each material to perform its optimal function while working together as an integrated component
Solution Approach 2:
The metal stem acts as an intermediary between the ceramic tip and the spring mechanism. It provides mechanical guidance, prevents tipping, and transmits forces while allowing the ceramic tip to maintain its corrosion-resistant properties
3Stress or pressure
If the spring force is increased to restrict fluid flow, then back pressure is improved, but the spring may buckle which worsens device reliability
Solution Approach 1:
The metal stem acts as an intermediary between the spring and the ceramic tip, providing mechanical guidance and support. This intermediary structure prevents spring buckling by ensuring proper alignment and force transmission, allowing the spring to generate high back pressure without structural failure
4Speed
If the poppet is made lighter for rapid response, then response speed is improved, but the poppet may vibrate more which worsens system stability
Solution Approach 1:
The segmented poppet design with ceramic tip and metal stem creates a structure that is both lightweight for rapid response and sufficiently rigid to minimize vibration. The metal stem provides structural integrity while the ceramic tip reduces overall weight compared to a fully metal construction
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 effectively maintains constant back pressure over the operating range of SFC systems, preventing damage from CO2 phase changes and rapid decompression, while reducing vibration and noise, thus enhancing system stability and performance.
Implementation Method 1
a spring arranged to bias the poppet toward the seat to restrict fluid flow through the fluid pathway
Implementation Method 2
a damping member disposed between the housing and the poppet and arranged to absorb energy and inhibit vibration of the poppet
Implementation Method 3
The poppet has a flow channel arranged on a side of the poppet so as to cause a biasing of the poppet, as fluid flows through the fluid pathway, such that vibration of the poppet is inhibited
Implementation Method 4
The housing has helical grooves along the cavity to cause a vortex around the poppet, as fluid flows through the fluid pathway, such that vibration of the poppet is inhibited
Data Source
AI summary
The invention generally provides a static back pressure regulator. In exemplary embodiments, the static back pressure regulator includes a seat that defines part of a fluid pathway, a poppet, a spring arranged to bias the poppet toward the seat to restrict fluid flow through the fluid pathway, and a calibration element configured to adjust a force applied to the poppet by the spring. The calibration element can include a through hole that forms part of the fluid pathway. The poppet can include a first guiding portion that extends into the through hole of the calibration element and inhibits tipping of the poppet relative to the seat.