The Problem
No Off-the-Shelf Vessel Met the Requirements
Supercritical CO₂ research requires pressures above 1,000 psi combined with precise internal geometry and optical transparency for observation. No commercial vessel met the combined requirements of pressure rating, non-cylindrical internal cavity, and optical access.
The challenge was to engineer a vessel from first principles that could safely contain supercritical CO₂ while enabling visual and sensor access to the experiment inside.
The Approach
Designed Ground-Up, Validated by Analysis
The vessel was designed with a square internal cavity — a non-standard geometry requiring careful stress concentration analysis at corners to ensure adequate safety margins at operating pressure.
- Stress and fatigue analysis on 304 SS body and B7 bolting under cyclic high-pressure loading
- Sapphire windows sized to accommodate dual 2 cm prisms for optical access
- Multi-tiered BOM integrating CO₂, vacuum, and sensor interfaces
- Modular assembly standardization for repeatable configuration
CAD Views
Assembly & Cross-Section
Key Engineering Decisions
Trade-offs That Defined the Design
304 SS selection: Chosen for corrosion resistance in CO₂ environments and machinability, with stress analysis confirming adequate safety factors at 90+ ATM.
Square internal cavity: Required stress concentration factor analysis at corners. Provided specified experimental control versus cylindrical alternatives.
Sapphire over borosilicate: Superior pressure rating and scratch resistance — enabling visual access without compromising vessel integrity.
