Industrial & commercial CA stores — atmosphere held for months, at plant scale.

Industrial & Commercial CA Stores

Controlled Atmosphere storage slows respiration and metabolism in fresh produce by regulating oxygen, carbon dioxide, nitrogen, humidity and temperature together. At commercial scale the engineering problem is no longer the recipe for one room — it is holding twenty rooms on twenty different recipes, proving each cell is gas-tight, and doing it with a plant that a technician in Multan can actually service. The equipment below is Fruit Control Italiana, integrated by our own engineers.

GAC 5000 computerised analysis group

The GAC 5000 consists of CO₂ and O₂ analysis groups with management software running on PLC logic and a supervising PC. It connects over the network to the CA machines and to the sensors inside each storage cell, giving surveillance, data storage and print-off of every storage parameter — CO₂, O₂, ethylene, temperature, humidity and pressure — as well as control of the appliances themselves. Every measured value is stored and can be plotted and printed as a graph.

Because hardware and software are designed by one manufacturer, the system can be shaped to the operator rather than the other way round. Connected to an internet line it allows long-distance support, remote management of the entire installation, and remote modification of set parameters — which is how a store in Punjab gets specialist attention without a specialist on site. One station can manage additional warehouses. Dedicated software runs cell tightness tests and memorises the results, and the apparatus can be coupled to a gas chromatograph where ethylene concentrations must be measured precisely.

Swingtherm-BS — catalytic ethylene removal

The Swingtherm-BS is a catalytic converter that removes ethylene and volatile odorous products of decomposition from both normal and controlled-atmosphere cells. Maintained economically, it holds:

• Refrigerated and C.A. cells, apples — < 1 to 5 ppm
• Citrus, pear and vegetable cells — 0.05 to 0.1 ppm
• Kiwi cells — < 0.02 ppm

The result is prevention of undesired ripening and of the physio-pathologic effects of ethylene, a very low level of spore and bacteria owing to thermal shock inside the reactor, and no disturbance to the thermal balance of the cell — the work cycle is designed to limit heating of the processed air.

Intelligem IG — CO₂ adsorption for DCA

The Intelligem IG adsorbers handle CO₂ adsorption in DCA (Dynamic Controlled Atmosphere) stores — the Fruit Control patented "Swinglos" protocol. Two tanks filled with active carbon give continuous adsorption on the room, engineered for storage at low CO₂ concentrations. A patented regeneration and adsorption cycle saves energy, and the units carry the best performance-to-installed-power ratio available — which is a running-cost argument before it is an environmental one. Critically, no nitrogen generator is required to maintain dynamic atmospheres at low levels, and undesired oxygen emission is reduced to a minimum.

Nitrogen production — Fighter, Bravo and Swan

The Fighter, Bravo and Swan generators produce nitrogen at 95% to 99% purity by molecular-dimension separation of atmospheric air compressed by a screw compressor. They are used for rapid pull-down in controlled-atmosphere cells — avoiding the contemporary formation of CO₂ — and for re-establishing storage conditions, including ULO, in cells that have been opened for partial sale of stored goods.

The nitrogen is "ecological" — free from combustion residuals such as CO₂, CO, NOx, SO₂ and C₂H₄ — which is why these units are specified where product contact matters. They are available as fixed or mobile units, including aboard ships and containers or for pull-down across several plants. They can also produce oxygen-enriched air up to 40% for ripening cells. The Fruit Control membrane generators operate on a totally clean principle — the only waste product is a mixture of air and oxygen — and reach significantly higher flow rates.

Reference — HAC Agri, 3,000-ton CA store

Our largest controlled-atmosphere project is a 3,000-ton CA store on an ammonia-glycol refrigeration design: twenty CA rooms in two banks off a central corridor, with a sorting area, receiving area, blast chillers, a dedicated control room and plant room, and civil provision for a further expansion phase. It is the reference that shows the difference between a CA room and a CA plant. See the HAC Agri project page.

Where it fits

Apples (Royal Gala, Gala Must, Red Delicious), dates (Aseel, Dhakki, Begum Jangi), kinnow and citrus, stone fruit, tomatoes and peppers, leafy greens and cut flowers — each crop has its own atmosphere recipe, and at this scale each room can hold a different one. For a single room or a smaller installation, see controlled atmosphere stores; for the refrigeration plant that sits behind either, see industrial & commercial refrigeration.