• Bulk containers: lining and filling


    The same inspection procedure must be carried out as for bagged coffee (see topic 05.02.04): a container is either suitable or it is not.

    The liner itself 

    This is best described as an oblong sack or envelope whose size is equivalent to the inner space of a 20 foot container (TEU). It is attached to hooks in the upper corners after which loose coffee is blown in, gradually filling the entire container with coffee. Container liners are used in the containerized bulk shipment of dry free-flowing cargo such as coffee. They are quick and simple to install and enable bulk cargo to be shipped door to door with a minimum of handling, thereby minimizing cargo spillage and waste.

    Liners are usually made from virgin polyethylene (film or woven polyolefins), allowing coffee to be transported safely in an enclosed chamber, thus avoiding contamination from pollutants and salt sea air. The liner therefore protects the coffee from external influences such as moisture and, in case of condensation occurring on the container's inside walls, it ensures that this does not affect the coffee.

    Once full the liner is sealed and not opened again until discharge at destination, either into the reception system of a roasting plant, or into a silo storage system, for example in a port. Bulk shipping means no export bags are required anymore whereas more coffee fits into the container (variable but generally about three tonnes more), thus saving on transport costs. Bulk coffee is discharged mechanically at the receiving end, thus avoiding the use of expensive manual labour. In Western Europe the disposal of empty coffee bags costs money as well. Because the United States mostly works on the ex dock sale system it seems relatively little coffee goes there in bulk. But today's large European roasters receive as much as 90% in bulk. Being able to supply coffee in bulk is a definite advantage therefore, with cost savings for both shipper and receiver.

    Fixing the liner 

    The inner polypropylene liner must fit snugly against the walls, roof and floor when full - improper placing of the inlet could cause tearing - and the load must be as evenly leveled as possible. The liner's roof must not sag but must be tight so at no time will the inlet or roof rest on the coffee after loading. Ideally, built-in reinforced straps in the liner's front panel (bulkhead) will prevent bulging when the container is full, thus allowing for easy closing of the doors. (Strapping ropes can also be used.) There should not be any pressure on the doors when closed after loading. The liner must be properly fastened to the container's interior, also at the far end: at the point of discharge the container is tilted to enable the coffee to slide out of the liner, rather than the filled liner sliding out of the container.

    Filling the container 

    Containers can be filled in two ways. One method is to take the coffee from the silo with the aid of a blower, or to empty individual bags into the blower's reception hopper. Blowing air into the liner makes it align itself with the walls, roof and floor of the container. Once the liner fits correctly inside the container, the blower then spews the coffee into the now fully lined container. During this process the displaced air must be able to escape.

    Do not blow a heap into the centre, leaving space at the rear and the doors, but fill the liner evenly. To ensure the coffee stays away from the hot container roof, avoid as much as possible contact between the stow and the liner's roof panel, preferably by a margin of about 70 cm. Some receivers stipulate that there must be space between the liner's roof panel and the top of the coffee load.

    Another way is to fill the container using a telescopic conveyor belt that extends into the lined box. This eliminates the need for air pressure and therefore the risk of damage to the beans.

    See topic 05.02.09 to view a lined bulk container.

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