Vacuuming technology is one of the most critical processes in manufacturing liquid nitrogen tanks. Although the vacuum layer is invisible from the outside, it plays a decisive role in determining the tank’s insulation performance, nitrogen evaporation rate, and overall service life. A high-quality vacuum layer ensures that a tank can maintain liquid nitrogen at −196°C for long periods with minimal loss.

The vacuum layer is created between the tank’s inner liner and outer shell, forming a double-walled structure. During production, specialized vacuum pumps remove air, moisture, and impurities from this space. The goal is to achieve an ultra-low pressure environment that prevents heat transfer through convection and significantly reduces conduction.

A key part of the vacuuming process is bake-out treatment, where the tank is heated while being pumped. This step forces trapped gas molecules and residual moisture out of the metal walls, ensuring a cleaner and more stable vacuum. Without proper bake-out, the vacuum level may degrade quickly after the tank enters service.

Many high-performance liquid nitrogen tanks also incorporate adsorption materials, such as activated charcoal or molecular sieves. These materials capture remaining gas molecules over time and help maintain a long-term high vacuum, even under environmental temperature changes.

Vacuum quality is measured through leak detection, which uses helium mass spectrometry to ensure that the tank has no micro-leaks. Even a tiny leak can cause vacuum decay, increasing evaporation rates and shortening the static holding time.

In summary, vacuuming technology is the foundation of a liquid nitrogen tank’s insulation. From ultra-high vacuum pumping to bake-out and leak detection, every step must be precisely controlled. A stable vacuum layer ensures superior nitrogen retention and reliable protection of stored samples.