Nitrogen generation control systems and methods for controlling oxygen content in containers for perishable goods
US5649995A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1995 |
| Grant date | Jul 22, 1997 |
| Priority date | — |
| Expiry date | Mar 9, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B2210/0046
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A nitrogen generation control system and method are provided for controlling levels of nitrogen and oxygen in a controlled atmosphere within a container for perishable goods. The nitrogen generation control system has a nitrogen generator that controllably generates an amount of nitrogen, while releasing oxygen as an off gas. The nitrogen is injected into the container to create a controlled environment. A sample analyzer subsystem is connected to the container to extract a sample of gases from the controlled environment and analyze the oxygen content. The control system further includes a cascaded, dual control loop controller coupled to the nitrogen generator and sample analyzer subsystem. The controller has a nitrogen generation control loop to control the amount of nitrogen generated by the nitrogen generator in response to variation between the oxygen released during nitrogen generation and a reference amount of oxygen. The controller also has a container atmosphere control loop to control the reference amount of oxygen used as a control input to the nitrogen generation control loop in response to variation between the actual oxygen content in the container and a preselected o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.