Growing costs related to ready-cleaned coffee beans and an increasing presence of impurities in green coffee have led companies to evaluate in-house treatment options. Further issues concerning ethical sourcing and the quality offered by single-origin products have fuelled the demand for green coffee cleaning and sorting systems, for medium and large roasting factories. The fewer the impurities there are, the greater the value of the end product. Companies are therefore seeing how vital it is to take control over the in-house treatment options and technologies in order to ensure constant raw product quality.
Plants processing 500 kg of green coffee per hour will be fine receiving 60-70 kg pallet-loaded jute bags of green coffee which will be handled indoors on a hopper and cut open manually. The hopper can be installed underground or on a supporting frame. Then the coffee is transferred to storage silos or directly to the roaster using an aspiration system.
The most convenient solution for plants with a larger capacity entails bag reception from trailers equipped with an integrated tilting unit, however it is just as easy to envisage extracting the bags from the container and placing them on a tilting unit inside the reception area. Combined with a sorting unit which handles the bags downstream, the bags can simply be fed one by one to the cutting unit. Belt conveyors are another flexible solution to bring the bags inside the facility. The conveyor can extend telescopically into the delivery truck allowing operators to position the bags on the swivel head. Implementing robotic technologies, IMA Coffee Petroncini is able to supply appropriate automatic bag opening or palletizing systems. This enables superb flexibility when production requires late bag picking.
Further options include a tilting platform for depalletization combined with a bag cutting unit. This improves efficiency when reception rates are around 750 bags per hour.
Facilities handling big bags without any form of automation will welcome an unloading station on top of the hopper. When higher production rates are necessary, bags can be unloaded onto a special structure including a spiked cutting device to open them without manual intervention.
Larger processing plants will tend to receive green coffee loaded onto a trailer or in a container. Petroncini solutions include outdoor hoppers for bulk loads arriving directly from a tilting unit. Coffee is then pneumatically transferred to storage silos within maximum 45 minutes after unloading.
Thanks to an alternating sliding mechanism combined with the hydraulic tilting of the container, this system is the most advanced, versatile, high-capacity system available today. Featuring sorting units which carry the bags downstream to the cutting unit, this system can accept up to 2 containers per hour. A special belt conveyor fitted beneath the shutter conveyors managing the bags collects any beans falling out of the bags, thereby ensuring virtually zero loss of product throughout the entire intake process. The bulk discharge unit is equipped with a dust aspiration system and safety panels that rise into place as soon as unloading starts.
In facilities handling upwards of 3 tons of raw coffee per hour, an in-house cleaning solution is an astute investment, because eliminating unwanted elements present in poorly cleaned coffee will significantly improve the commercial value of the end product itself. For this reason, IMA Coffee Petroncini has developed a wide selection of cleaning solutions, tailored to the most common situations. Getting the cleaning strategy right will have positive effects on the processing stages downstream. Firstly, the solution is selected according to the type and quality of product the customer receives and the capacity of the plant. Starting with a basic cleaning sieve, which can be fitted with a magnetic surface to eliminate iron-based impurities, customers can separate impurities that are finer and/or coarser than the coffee. These machines are connected to a filter for dust removal and are highly recommended to plants processing up to 500 kg/h, even when receiving ready-cleaned coffee. This doubles the effect of cleaning in order to be sure of removing all foreign bodies and thereby improving coffee quality.
In addition to basic cleaning solutions, IMA Coffee Petroncini can supply a dry destoner to remove foreign bodies with a specific weight greater than coffee, such as stones and pieces of metal. This can be combined with a densimetric/gravity table used to separate other beans or stones having almost the same size as coffee beans, based on the lower density such as wood and aluminum impurities. Separation technologies also include more advanced solutions. Nonetheless the destoner and gravity table, although they occupy more floor space, are both cost-effective.
Today’s most advanced technology is known as optical sorting. The major benefit is its capacity to sort by shape and by colour. Combined with initial basic cleaning equipment, optical sorting is extremely effective in completing the process. Moreover, it is a versatile solution as operators can adjust the separation parameters according to the frequency and importance of the defects to be assessed and eliminated. This means taking close control over the process and consequently optimising the profits.
Once cleaning operations have been completed, a weighing station ascertains the weight of the rejected material. Losses in product volume are compensated for by the incremental value of the sorted product. Specific solutions have been engineered by IMA Coffee Petroncini to sort coffee in multiple passes for the most accurate cleaning and also refill big bags after the whole cleaning process has ended.
Thanks to dust-tight aspiration, keeping the working area free from tiny contaminants, the coffee which may return to the big bags is not only clean, but practically dust-free.
The IMA Coffee Petroncini engineering department devotes much attention to ensuring maximum efficiency connecting one process to another in the processing facility, even though conveying itself does not directly add value to the coffee.
Appropriate conveying solutions are crucial to safeguard product integrity and optimise productivity and it can guarantee the highest preservation of the quality of the product, avoiding any product contamination thanks to the Hygienic Design specifications. Petroncini’ solutions include mechanical and pneumatic conveying equipment in pression or in suction, bucket elevators, chain conveyors. Each solution is designed to suit the plant, maximising its effectiveness.
Space availability, customer budget and the desired level of operations automation are the crucial factors that allow for a preliminary engineering analysis on the storage area. A tailored engineering solution should combine the customer’s logistics needs and production expectations with the available space and budget, taking into account the necessary manual operations involved.
Suitable storage time varies from a minimum of three days up to one month, considering the overall plant production, the number of coffee origins that will be used and the type of storaging the customer has planned, be it in silos or both in silos and in the warehouse. The choice of the type of storaging solution strictly depends on the availability of space and production planning.
IMA Coffee Petroncini supplies highly flexible solutions for both indoor and outdoor storage depending on the facility space available. To adapt best, square-shaped, polygonal or circular solutions are possible, together with rotary distributors and weighing devices specifically designed for green coffee processing.