Chart Inc.: Liquid nitrogen dosing system

Chart offers liquid nitrogen dosing systems to aid in oxygen reduction. To demonstrate this capability, the company evaluated several popular size and style containers to determine the effectiveness of the technology.

LN₂ is supplied to the doser by a vacuum-insulated hose and flows into the dosing head. A sensor detects the speed of the line (encoder compatible for higher speeds); a second sensor detects the presence of a container. When a container is detected, the dosing head opens and dispenses an exact amount of pure LN₂. The LN₂ gasifies and is either trapped in the container to add rigidity or escapes with oxygen to inert the headspace.

Several popular sizes and styles of vitamin supplements were tested, including softgels, tablets, caplets, and gummies. The containers were either PET or HPDE with foil or plastic inductive seals.

O₂ levels were measured with an Illinois Instruments’ 6500 Headspace Oxygen Analyzer. For this test, O₂ readings were taken to establish a baseline or “pre-dose” condition on each container. The O₂ level in the room was also noted. After these readings were taken, each container was dosed with liquid nitrogen using a Chart 0.090-in. nozzle for 100 ms. Results varied depending on the type of supplement and container, but overall there is a significant difference in O₂ levels post-liquid nitrogen dosing.

The testing demonstrated that the Chart LN₂ dosing system is capable of reliable oxygen reduction, oftentimes upwards of 70%.