Common uses for Liquid Nitrogen

Liquid Nitrogen is the ideal coolant and it has many cooling and cryogenic applications within the medical, pharmaceutical, industrial and food sectors.
From the cryopreservation of biological samples and cryotherapy for skin abnormalities, to the freezing of foodstuffs, Liquid Nitrogen’s usage is widespread.

Here are some typical Liquid Nitrogen applications:

Cryogenics

Cryogenics encompasses the arms of physics and engineering that include the study of extremely low temperatures – how to create them and how matter or materials behave under such temperatures.

Liquid Nitrogen is one of the most common liquefied gases (or cryogens) used in cryogenics. It is often the preferred element for freezing applications, such as the manufacture of statin drugs that require sub zero temperatures as low as -100ºC.

Cryopreservation

This process involves the preservation of tissues or cells by cooling to sub zero temperatures. The boiling point of Liquid Nitrogen is – 196ºC, at which any biological activity ceases, including the biochemical processes that would cause cell death. Cyroprotectant solutions must be utilised to prevent cell damage incurred in freezing or when warming up again.

Cryogenics is believed to offer indefinite longevity to cells and many biological materials may be successfully cryopreserved, including blood, semen, stem cells, tissue samples, eggs, embryos and plant shoots.

Analytical (LC-MS, GC, SEM)

When complex and high accuracy analysis is required, Liquid Nitrogen is the ideal liquid gas. Its analytical usage ranges from research and academic applications, to everyday quality control purposes.

For Liquid Chromatography-Mass Spectrometry (LC-MS); Gas Chromatography (GC) and Scanning Electron Microscopy (SEM), Liquid Nitrogen is utilised within the geochemical, petrochemical, forensic, medical, pharmaceutical, occupational health, agricultural sectors… and so the list goes on.

Liquid Nitrogen Dewar

Designed for the safe storage and dispensation of Liquid Nitrogen, dewars are the preferred container solution. They typically feature a snap on cap and necktube core to ensure tight closure and ease of access without exposure to the Liquid Nitrogen or cryogen.

Dewars must be robust, reliable and offer effective thermal efficiency. They are made from high performance materials and typically are encased in aluminium. Liquid Nitrogen is a hazardous material and it can cause serious injury if not handled carefully. Click here for more details on Liquid Nitrogen dewars.

Pipefreezing

Liquid Nitrogen is used to freeze stationary liquids in a section of pipe or tube. By creating an in-line ice plug that isolates the section, repairs or modifications may be made without draining or shutting off an entire system. Pipe freezing with Liquid Nitrogen is time efficient and cost effective.

Environmental Chambers

For the preservation of samples, Liquid Nitrogen may be used in environmental chambers – a more cost effective alternative to refrigerated chambers.

Blanketing

Liquid Nitrogen’s inert properties make it an effective blanketing solution – protecting flammable or explosive materials (solids and liquids) from exposure to air. Under a nitrogen atmosphere or ‘blanket’, certain chemicals, foodstuffs and surfaces of solids may be protected.

Food Freezing

Liquid Nitrogen’s intense cold enables rapid freezing of foodstuffs with minimal cell damage, whilst maintaining texture, appearance and flavour. Cryogenic tunnel freezers use the cold nitrogen gas flowing through to catalyse refrigeration from liquid vaporisation.

Modified Atmosphere Packing (MAP)

MAP uses Liquid Nitrogen to prolong the shelf life of fresh foods or those that are minimally processed. The fresh state of the foodstuff is prolonged by a technique that changes the make up of the air surrounding the package. Mould, oxidisation, moisture migration and insect infestation can be prevented.

Lead Free Soldering

Liquid Nitrogen is commonly used for lead free soldering within electronics assembly applications. Whilst minimising the amount of soldering dross produced, lead free soldering with Liquid Nitrogen controls the level of oxygen in the atmosphere, thus improving solder joint appearance and the level of board residues.

Rubber Deflashing

When cooled to very low temperatures with Liquid Nitrogen, materials such as rubber become hard and brittle. This enables the removal of flash or fins on cast rubber or plastics. Any imperfections may be broken off mechanically.

Shrink Fitting

Instead of traditional expansion fitting, Liquid Nitrogen is used in shrink fitting – cooling the inner part so that the metal shrinks and may be inserted into the outer part. Once it returns to normal temperature, the inner metal returns to normal size to provide a tight fit.

Foundries

Nitrogen is often used to treat the melt in the production of metals such as steel. It may also be used as a shield gas in heat treatments of iron, steel and other metals. Additionally, flash or fins on cast metal can be removed by cooling with Liquid Nitrogen to make the metal brittle so that they can be simply broken off.

Laser Cutting

Pure nitrogen performs as a cutting gas, preventing the fusion of the metal being cut which would allow air molecules to alloy the metal. In laser cutting applications, Liquid Nitrogen is heated to gaseous form to ensure the efficiency of the laser-cutting beam.