Liquid Nitrogen Supply Tank

1. Vacuum Insulation (Core Insulation System)

Multi-layer Reflective Screen: 30-50 layers of alternating aluminum foil, with a reflectivity of a Y95%, significantly reducing radiative heat transfer.

High Vacuum Chamber: Vacuum depth a 2A 10a A Pa, with a free path of gas molecules reaching several meters.

Adsorbent Filler: Activated carbon or molecular sieve, continuously adsorbs residual gas.

Technical Value: This structure reduces the daily evaporation rate of liquid nitrogen containers to 0.1%.

2. Inner Tank and Outer Shell

Components, Material Selection, and Features
Inner Tank: 304 Stainless Steel/Aluminum Alloy, -196A C cryogenic resistance, intergranular corrosion resistance.
Outer Shell: 304 Stainless Steel/Aluminum Alloy. Protects against mechanical shock and maintains the integrity of the vacuum layer.
3. Neck Tube and Sealing System

Neck Tube Design: Slender structure (length-to-diameter ratio a Y 5:1) reduces heat conduction. Available in diameters from 35 to 500mm, it adapts to various scenarios.

Seal:

Polyurethane neck plug (resistant to -200A C) blocks cold air from escaping the tank opening.

II. Type Differences

1. Structural Features of Storage-Type Liquid Nitrogen Tanks

Optimized Static Insulation: Thicker insulation layer, daily evaporation rate a 0.08%

No Shockproof Design: For use in fixed locations only, suitable for long-term storage of laboratory samples.

2. Transport-Type Features

Road Transport: Enhanced liner support reduces vibration and sway.

Air Transport: Includes Adsorbent material absorbs liquid nitrogen and releases nitrogen gas, eliminating liquid nitrogen from the tank and ensuring smooth security inspection.

3. Features of Self-pressurized Liquid Nitrogen Containers

Vaporization and Boosting Module: Boosting pipe + Boosting valve (<0.1 MPa)

Dual Safety Valve Design: Dual pressure relief provided by a mechanical valve and a bursting disc

Note: Self-pressurized models are often referred to as liquid nitrogen cylinders or Dewar flasks and are used for liquid nitrogen replenishment in various locations.

III. Structural Innovations in the Safety System

1. Pressure Protection Mechanism

Pressure Balancing Valve: Automatically adjusts the internal and external pressure differential (threshold A 0.01 MPa)

Overpressure Protection: Dual safety valves activate to relieve pressure at a Y0.09 MPa

2. Intelligent Monitoring Integration

Sensor Type Monitoring Parameters Accuracy Standards
Electronic Liquid Level Gauge: Liquid Nitrogen Residual A 3%
Temperature Probe: Gas/Liquid Phase Temperature A 1A C
IV. Industry Evolution of Liquid Nitrogen Tank Structures

1. Material Upgrade Path

Traditional: Stainless Steel Housing (Heavy and Costly) a Lightweight: Aviation Aluminum Housing (30% Weight Reduction)
Adsorbent Iteration: Silica Gel a Molecular Sieve-Activated Carbon Composite (Adsorption Efficiency Doubled) 2. Intelligent Integration Trends

Predictive Maintenance: AI analyzes evaporation rate curves to provide early warning of vacuum decay.

V. Selection and Maintenance Recommendations

1. Structural Selection Strategy

Biological Sample Bank: Choose a vapor phase tank (large diameter + internal partitions, storage density a Y 2000 tubes/m2).

Industrial Site: Choose a pressurized liquid nitrogen supply tank (compatible with production line connection).

2. Maintenance Key Points for Extending Lifespan

Annual Inspection: Vacuum level (a 5 A 10a A Pa), seal elasticity (compression set a 15%).

Cleaning Standards: Wipe the neck with anhydrous ethanol; do not use metal tools to remove frost.

The intricacies of liquid nitrogen tank structural design lie in balancing insulation efficiency, safety, and practicality. Understanding its technical characteristics will facilitate informed selection and standardized operation.