The internal canister, often referred to as the “lifting canister” or “sample canister,” is one of the most essential components inside a liquid nitrogen tank. Although it appears simple, its structure, materials, and layout directly determine the safety, accessibility, and preservation quality of stored biological samples. A well-designed internal canister ensures not only efficient storage but also stable low-temperature conditions essential for long-term sample protection.

One of the primary design considerations is the material selection. Canisters are commonly made from high-strength aluminum alloys or stainless steel. Aluminum offers excellent thermal conductivity, allowing samples to quickly reach cryogenic temperatures, while stainless steel provides superior durability and corrosion resistance. The choice depends on application needs and the required balance between weight and strength.

Another important design aspect is the perforation layout. Holes on the canister walls promote rapid temperature equalization and nitrogen circulation, which helps samples achieve a uniform −196°C environment. However, perforation size must be optimized: too many holes may compromise structural integrity, while too few can slow cooling efficiency.

The bottom design—leak-bottom versus non-leak-bottom—also plays a crucial role. Leak-bottom canisters allow nitrogen to flow through more freely, improving cooling speed, while closed-bottom designs offer better protection for delicate sample vials by minimizing direct contact with frozen debris.

Proper handle design ensures safe and smooth lifting. Handles must remain easy to grip even when frost forms, and they should provide enough length to prevent operator exposure to extremely cold vapor.

Overall, the internal canister is more than just a storage accessory—it is a critical engineering component that ensures sample integrity and operational convenience. Thoughtful design directly enhances both safety and performance in cryogenic applications.