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Tunnel Freezing and Flash Freezing Food with Nitrogen: Oxygen Monitors and Why They May be Required

  • By : PureAire Monitoring Systems
  • Posted on : November 17, 2016
flash freezer oxygen monitor nitrogen

New developments in cryogenic freezing are transforming the frozen food industry by making it easier to freeze all sorts of items quickly while retaining the highest nutritional value. Cryogenic and tunnel freezers are easy to use, yet they pose a hidden health risk. Learn why you may need an O2 monitor if your frozen food manufacturing facility relies on cryogenic freezers.

How Cryogenic Freezers Work

Cryogenic freezers allow for continuous freezing of food, increasing output without requiring a large amount of space. Compared to mechanical freezers, which take longer to freeze products, they increase both the production and the quality with a low investment of capital.

In particular, cryogenic freezers are useful for freezing par-baked goods, which are partially baked before being frozen for storage. Par-baked items allow fast-food restaurants, supermarkets, sandwich shops, cafes, and other institutions to offer fresh, healthy baked goods without needing to bake from-scratch every day. For a commercial baking facility, investing in a cryogenic freezer is the best way to increase their output, grow their business, and become more profitable.

Cryogenic freezers work by using liquid nitrogen to quickly chill items to safe temperatures for frozen storage. As in any environment where liquid nitrogen is present, there is a danger of oxygen depletion and asphyxiation. Thus, it is always a good idea to have an O2 deficiency monitor present onsite to protect the health of employees.

One subset of cryogenic freezers, the tunnel freezer, uses a continuous freezing model of a conveyor belt, an injection system, and an exhaust system to vent gases. When the texture of the finished product is paramount, as in baked goods or seafoods, or when it’s necessary to flash freeze hot foods quickly, a tunnel freezer is the best way to maintain quality in the end product.

Why an Oxygen Monitor is Necessary for Cryogenic Tunnels 

Oxygen Monitor for Nitrogen Tunnel       Freezing

As mentioned above, cryogenic tunnel freezers rely on an inert gas, nitrogen, to flash freeze food items. Nitrogen is perfectly safe when used in the closed-loop freezer system and properly vented from the facility. However, if the exhaust system were to develop a leak, nitrogen gas could enter the manufacturing facility and start to displace oxygen from the air. Since nitrogen is colorless and odorless, staff would not notice the leak. In a matter of minutes, ambient levels of oxygen could drop so severely that staff could become disoriented, lose consciousness, or die.

Simply by installing O2 monitors wherever nitrogen gas is used or stored, you can monitor levels of oxygen in the air and ensure there is no risk of oxygen displacement from a nitrogen leak. In the event that nitrogen leaks into the environment, the O2 deficiency monitor will sound an alarm and flash lights to let staff know that oxygen levels have fallen below the acceptable threshold set by OSHA. Staff can then evacuate before their health is compromised.

There are many styles of O2 monitors, but the one we recommend for flash freezing environments is the Sample Draw oxygen monitor. The style of O2 monitor can be placed outside the freezer and monitor levels of oxygen inside the freezer using a polyurethane tube. This ensures the sterility of the flash freezing environment while safeguarding workers. With a state-of-the-art zirconium oxide sensor, this style of oxygen detector can last without any maintenance for up to 10 years.