Cryogenic tanks, or cryotanks, are storage systems used to store frozen biological materials and offer a number of unique benefits. The main function of cryotanks is the storage of cryogenic liquids and super-cold fuels.
These can include liquefied gases, such as liquid argon, oxygen, or nitrogen. These liquified gasses are stored at -150 ºC or less. Cryogenic storage tanks are also used for gasses such as liquefied natural gas, carbon dioxide or nitrous oxide, that need to be kept at slightly higher temperatures.
Many industries require cryogenically stored gases used for a wide range of industrial applications. In the life sciences, cryogenic tanks are often used for the storage of biological samples, like embryos and oocytes for fertility clinics. Cryogenic vials are specialized storage containers that are used to store biological samples in cryotanks, such as cell cultures, blood, serum, eggs and embryos, or sperm. Often, long term storage is needed for these types of samples, and cryotanks are the perfect solution.
Cryosurgery uses cryogenically stored gases for surgical interventions, from relatively minor procedures, such as the removal of warts, to the surgical removal of cancerous tissue. Cryoelectronics, is another application that involves the study of superconductors and their properties under cryogenic conditions. This technology is useful for investigating electronics in cryogenic environments and plays an important role in the development of satellite and spacecraft technology.
The basic structure of a cryotank consists of two shells. The first shell is called the inner shell, and is the product container. It is usually made of stainless steel. The second, outer shell, is also called the vacuum jacket. This outer shell tends to be made from carbon steel. Air is removed from the space between the two shells to create a vacuum, which helps provide better thermal insulation.
Hazards of Cryotanks
There are a number of hazards to consider when it comes to the use of cryotanks. Severe frostbite or cryogenic burns are possible if cryogenic liquids come into contact with the skin. Cryogenic liquids can cause major damage if they come into contact with other equipment or the infrastructure of a laboratory, such as pipes, laboratory benches and laboratory floors.
Asphyxiation is a potential risk if liquid nitrogen is used or released in a poorly ventilated area. This is not due to the toxicity of liquid nitrogen, but because liquid nitrogen can rapidly evolve into nitrogen gas. The nitrogen gas can then accumulate, displacing the air oxygen in the room, leading to the risk of asphyxiation.
Cryogenic storage tanks also pose an explosion risk due to rapid pressure changes that can occur within cryogenically stored liquefied gas. It is essential that cryogenic liquids are only kept in specifically designed storage vessels. These vessels should always be maintained to the highest standard, under strict safety guidelines.
Cryogenic tanks are usually fitted with pressure release valves, so if pressure does begin to build up inside them, it can be released gradually and safely in a controlled manner. However, a widely circulated accident report following an explosion involving one of these tanks highlighted a number of serious errors. The tank in question was old – these tanks have a shelf life, and once they reach a certain age they need to be replaced. The pressure release valves on the tank in question had failed in the past, and instead of being replaced with new valves, the tank was simply sealed with metal plates. Early morning, at 3 am, the pressure in the tank increased rapidly and with no pressure release valves, the tank exploded and shot upwards like a rocket. It passed through the first and second floor ceilings above finally coming to rest on the third floor of the building. The explosion stripped tiles off the laboratory floor. Shooting upwards, the tank smashed into two water mains and the electrical cables above them, pushing them into the concrete ceiling and cracking it. If this incident had taken place during the day, more than just pipes and ceilings would have been damaged.
Laboratory managers can take a number of measures to proactively protect against these types of risks. Training all personnel who use and come in contact with cryogenic tanks and liquids, perform processes that involve the use of cryogenic tanks, and interact with any samples stored in them, is absolutely paramount. Safety precautions should be taken at all times, and appropriate protective gear should be worn, such as goggles, helmets, gloves and overalls.
All equipment, such as the tanks themselves, their safety valves and connectors, and any pipework or instruments used for cryogenic processes must be maintained to the highest standard, and replaced regularly according to a planned maintenance schedule. If any signs of damage or wear and tear are noticed, then the damaged component must be replaced immediately.
Egg and embryo storage facilities, and any other facility storing liquid gases in cryotanks, can implement systems and processes to protect against liquid nitrogen levels dropping too low in the cryotanks, endangering eggs and embryos, or any other sample stored. These systems and processes include daily tank inspections, alarm systems that send alerts when levels are low, or electronic fillers that automatically replenish the cryotanks to appropriate levels.
State-of-the-art systems will include real time monitoring of for cryotanks and stored cryogenic liquids to closely manage temperature levels. This is because material temperature fluctuations can result in damages to the chromosomes of an egg, tissue samples may be damaged, or cell cultures may develop damaging ice crystals.
An equally significant concern from a safety perspective is if a rapid increase in temperature leads to a rapid expansion of stored liquefied gas, resulting in increased pressure inside a cryotank, which could lead to an explosion, as detailed above.
The XiltriX Solution
A state-of-the-art laboratory monitoring system such as XiltriX, can play a key role in mitigating these risks. XiltriX provides real-time monitoring of temperatures and pressures inside cryotanks and other storage tanks. If the temperature in a cryotank begins to increase, XiltriX can immediately alert the appropriate staff, providing peace of mind 24 hours a day, seven days a week.
XiltriX automatically logs and records data from temperature outputs and other parameters relating to cryogenic storage systems. This data can then be leveraged to produce automated reports that help your laboratory adhere to regulatory requirements and improve quality control and assurance. It also simplifies the audit process, with a unified platform to access all cryogenic storage data records.
Cryotanks offer a number of unique and specialized features for life science organizations and utilizing them in conjunction with a laboratory monitoring system like XiltriX, can ensure their safe and efficient use in any laboratory.
Want to discover how XiltriX can help you sleep at night and protect your laboratory? Contact us now to find out!