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Controlled Atmosphere Chamber


Vegetables and fruit respire; they take in oxygen (O2) and give off carbon dioxide (CO2). The storage of fruit and vegetables in a gas-tight environment allows the oxygen level in the air to be lowered and the level of CO2 to increase. Long-term storage of vegetables and fruit actually involves inhibiting the ripening and ageing processes, thus retaining flavour and quality. Ripening is, in fact, postponed. This occurs as a result of modifying the gas conditions in the cool cell so that the respiration of fruit and vegetables is reduced.

Controlled Atmosphere (CA) is a storage technique whereby the level of oxygen is reduced and CO2 is increased. Quality and the freshness of fruit and vegetables are retained under Controlled Atmosphere conditions without the use of any chemicals. Under CA conditions, many products can be stored for 2 to 4 times longer than usual.

What do you need for CA storage?

  • CO2-scrubbers :
  • CO2-scrubbers are used to manage the CO2 levels in the cool cell. Air from the storage area is removed by the scrubber, and the CO2 purified air is then fed back in.
  • O2 scrubbers :
  • With a CA scrubber (also known as a nitrogen generator or separator), the fruit can be quickly brought under CA conditions once the space has been filled or after a connecting door, for example, has been opened
  • Ethylene converters :
  • Fruit varieties that are sensitive to ethylene (under CA conditions), require an ethylene converter. The ethylene converter from BLUE ICE removes ethylene from the cool cells using catalytic combustion; ethylene can thus be maintained at any required level.
  • Control system :
  • A control system measures and registers O2 and CO2 and operates the CO2 and O2 scrubbers. In addition, the same control system can regulate cooling (switching on/off, defrosting, machine room regulation), carry out ethylene measurements and operate the ethylene converter.
  • Humidification :
  • Fruit that is stored in a CA/ULO cell always loses moisture. This moisture loss reduces if the RH levels (relative humidity) are kept above 90%. Cooling takes water out of the atmosphere, thus limiting the storage period and quality. A humidification system means that relative humidity can be kept up to scratch.
  • Gas-tight cool cells :
  • CO2-scrubbers are used to manage the CO2 levels in the cool cell. Air from the storage area is removed by the scrubber, and the CO2 purified air is then fed back in.
  • Accessories :
  • Finally, the CA cool cell is also fitted with a couple of accessories that are vital for VA storage;
    - a flexible buffer (also called a ‘lung’) absorbs pressure differences in the cool cell without oxygen streaming into the cell.
    - under and over pressure valves ensure that larger pressure differences (which cannot be accommodated by the air buffer) are evened out so that the cool cell is not damaged.