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The Liquid Hydrogen and Liquid Helium Vacuum Cold Box Shells are specialized storage systems designed to maintain -253°C (LH2) and -269°C (LHe) under vacuum insulation. Constructed with double-wall stainless steel (304L/316L), these cold boxes integrate multi-layer insulation (MLI) and copper radiation shields to minimize boil-off rates (BOR) to ≤0.1% per day—critical for preserving high-value cryogenic fluids .
Vacuum Insulation: A 20–50 mm vacuum gap between inner and outer shells (evacuated to ≤1 Pa) reduces conductive and convective heat ingress by 99% compared to ambient insulation .
MLI: 30–50 layers of aluminized polyester film (12 μm thickness) with glass fiber spacers (25 μm) create a thermal barrier, reducing radiant heat transfer by 98% .
Copper Radiation Shield: A 0.5–1 mm thick copper layer, dynamically cooled by return gas or liquid nitrogen (to -196°C), intercepts 70–80% of radiant heat from the outer shell.
Extreme Temperature Resistance
Withstands -269°C to +50°C thermal cycles without structural degradation, thanks to stress-relieved welds and low-temperature-grade stainless steel (316L with 40 J impact energy at -196°C) .
Stainless steel 316L inner shell (6–12 mm thickness) resists hydrogen embrittlement and helium permeation, critical for long-term storage integrity.
Low Maintenance and Longevity
Vacuum integrity is tested to ≤1 Pa every 2 years, with replaceable zirconium-aluminum getter cartridges (activated at 400°C) extending vacuum life to 10+ years .
Modular valve boxes (e.g., Demaco’s DVB series) integrate pressure relief valves, level transmitters, and fill/drain ports, allowing maintenance without breaking the vacuum.
Safety and Compliance
Certified to ASME BPVC Section VIII, Division 2 (for cryogenic vessels) and EN 14620 (cryogenic storage tanks), ensuring design safety for extreme temperatures.
Dual-pressure relief valves (set at 1.2× working pressure) with rupture discs (1.5× working pressure) provide redundant over-pressure protection.
Hydrogen Energy Storage: Bulk storage for LH2 refueling stations (5–20 m³ tanks) supporting fuel cell vehicles, with BOR ≤0.08%/day to minimize hydrogen loss.
Medical Research: LHe storage for MRI magnets (1,000–5,000 liter capacities), maintaining -269°C to keep superconducting coils operational.
Aerospace Propulsion: LH2 storage for rocket launch pads (100 m³ tanks with BOR ≤0.05%/day), ensuring propellant availability for launch windows.
Q: How is vacuum maintained in the cold box?
A: Non-evaporable getter (NEG) pumps (zirconium-based) continuously absorb residual gases (H₂, O₂, N₂) from the vacuum gap, maintaining pressure ≤1 Pa without external power. Getters are reactivated every 5 years via electric heating .
Q: Can cold boxes be buried underground?
A: Yes. Buried models include cathodic protection systems (sacrificial anodes) to prevent soil corrosion and a concrete outer casing for structural support. Installation time is 20% longer than above-ground units due to excavation requirements .
Q: What is the cost difference between LH2 and LHe cold boxes?
A: LHe cold boxes are 30–50% more expensive due to stricter purity requirements (helium leak rates ≤1×10⁻⁹ mbar·L/s) and specialized MLI with higher layer counts (50 vs. 30 layers for LH2) to combat the lower temperature differential .
The Liquid Hydrogen and Liquid Helium Vacuum Cold Box Shells are specialized storage systems designed to maintain -253°C (LH2) and -269°C (LHe) under vacuum insulation. Constructed with double-wall stainless steel (304L/316L), these cold boxes integrate multi-layer insulation (MLI) and copper radiation shields to minimize boil-off rates (BOR) to ≤0.1% per day—critical for preserving high-value cryogenic fluids .
Vacuum Insulation: A 20–50 mm vacuum gap between inner and outer shells (evacuated to ≤1 Pa) reduces conductive and convective heat ingress by 99% compared to ambient insulation .
MLI: 30–50 layers of aluminized polyester film (12 μm thickness) with glass fiber spacers (25 μm) create a thermal barrier, reducing radiant heat transfer by 98% .
Copper Radiation Shield: A 0.5–1 mm thick copper layer, dynamically cooled by return gas or liquid nitrogen (to -196°C), intercepts 70–80% of radiant heat from the outer shell.
Extreme Temperature Resistance
Withstands -269°C to +50°C thermal cycles without structural degradation, thanks to stress-relieved welds and low-temperature-grade stainless steel (316L with 40 J impact energy at -196°C) .
Stainless steel 316L inner shell (6–12 mm thickness) resists hydrogen embrittlement and helium permeation, critical for long-term storage integrity.
Low Maintenance and Longevity
Vacuum integrity is tested to ≤1 Pa every 2 years, with replaceable zirconium-aluminum getter cartridges (activated at 400°C) extending vacuum life to 10+ years .
Modular valve boxes (e.g., Demaco’s DVB series) integrate pressure relief valves, level transmitters, and fill/drain ports, allowing maintenance without breaking the vacuum.
Safety and Compliance
Certified to ASME BPVC Section VIII, Division 2 (for cryogenic vessels) and EN 14620 (cryogenic storage tanks), ensuring design safety for extreme temperatures.
Dual-pressure relief valves (set at 1.2× working pressure) with rupture discs (1.5× working pressure) provide redundant over-pressure protection.
Hydrogen Energy Storage: Bulk storage for LH2 refueling stations (5–20 m³ tanks) supporting fuel cell vehicles, with BOR ≤0.08%/day to minimize hydrogen loss.
Medical Research: LHe storage for MRI magnets (1,000–5,000 liter capacities), maintaining -269°C to keep superconducting coils operational.
Aerospace Propulsion: LH2 storage for rocket launch pads (100 m³ tanks with BOR ≤0.05%/day), ensuring propellant availability for launch windows.
Q: How is vacuum maintained in the cold box?
A: Non-evaporable getter (NEG) pumps (zirconium-based) continuously absorb residual gases (H₂, O₂, N₂) from the vacuum gap, maintaining pressure ≤1 Pa without external power. Getters are reactivated every 5 years via electric heating .
Q: Can cold boxes be buried underground?
A: Yes. Buried models include cathodic protection systems (sacrificial anodes) to prevent soil corrosion and a concrete outer casing for structural support. Installation time is 20% longer than above-ground units due to excavation requirements .
Q: What is the cost difference between LH2 and LHe cold boxes?
A: LHe cold boxes are 30–50% more expensive due to stricter purity requirements (helium leak rates ≤1×10⁻⁹ mbar·L/s) and specialized MLI with higher layer counts (50 vs. 30 layers for LH2) to combat the lower temperature differential .
