Liquid air food freezer and method
US5921091A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Oct 3, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25D29/001
- WIPO fieldFood chemistry
- WIPO sectorChemistry
Abstract
A cryogenic freezing method uses a mixture of liquid nitrogen and liquid oxygen in amounts approximating the composition of atmospheric air to freeze food products. The mixture preferably includes 18% to 25% oxygen and the balance nitrogen, with small amounts of residuals which are commonly found in air. The present invention involves replacing a liquid carbon dioxide or liquid nitrogen cooling medium which is used in known cryogenic freezers with a liquid nitrogen and liquid oxygen mixture. The liquid nitrogen and oxygen mixture can be used according the present invention in many of the known freezers using liquid carbon dioxide or liquid nitrogen as a cooling medium, including tunnel freezers, spiral freezers, and immersion freezers. The use of a liquid nitrogen and liquid oxygen mixture improves the efficiency of a freezer because the cold vapors are not exhausted from the freezer. In addition, the leakage of vapors from the freezer into the room air will not create unsafe conditions for workers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.