Henan Tianchi Instrument & Equipment Co., Ltd.

New users of liquid nitrogen cans may notice a seemingly "loose" neck plug when first using the container, leading to concerns about potential quality issues.

However, this is perfectly normal and by design.

The neck plug is made from high-performance polyurethane, selected to minimize nitrogen evaporation at the container’s opening while maintaining the stability of the internal environment.

Given the extremely low boiling point of liquid nitrogen (-196.56°C), even in a vacuum-insulated container, slight natural evaporation still occurs. Without proper release, this evaporated nitrogen can accumulate and raise internal pressure, potentially leading to a dangerous explosion.

To prevent this, manufacturers design the neck plug to be slightly loose, with a groove to act as a vent. This allows evaporated nitrogen to escape safely, avoiding pressure buildup.

Users should avoid blocking the neck with plastic bags or other materials, as this can dangerously increase internal pressure, compromising safety and potentially damaging samples.

The best practice is to follow manufacturer guidelines for safe and efficient use of the liquid nitrogen jar, ensuring both sample stability and user safety.