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Wherever large quantities of bulk solids are moved, the wish list for process engineers is long: conveying, loading, transporting, filtering, mixing should be as fast as possible, ideally highly efficient with maximum safety for the process and employees and without costly or maintenance-intensive technology.

Loading systems can meet these requirements almost completely, if they are designed correctly. The key technology, which manufacturers call loading bellows of telescopic loading spouts or chutes, is used at an interface that is particularly sensitive for a successful loading process. Only little time is available for loading into silo vehicles, open trucks, transport wagons or big bags, because downtimes cost money. At the same time, loading should not only be fast, but also clean without material losses due to leakages, poor positioning or the escape of dust, because the costs for this should not be underestimated.

It becomes really expensive when the dust causes harm to workers, the environment or equipment. Dust on pavements, ladder rungs or handholds is the lesser cause of accidents. Exposure to dust over a long period of time can cause severe damage to the heart and respiratory tract. If dusts penetrate machines and sensitive technology, there is a risk of defects or even total failure. Conductive dusts such as those produced in welding shops have already been the cause of short circuits and even seemingly harmless flour dusts can be responsible for explosions.

The balancing act between a dust-free, safe working environment and fast, efficient loading succeeds when the loading system, bulk material and application are perfectly matched. The loading all-rounder that can do everything and always fits is a thing of the past. Specialists are needed here:

Product example Premix (plastic)

Premix of plastic granulate is a dry, very dusty and fine powdery material with a bulk density of 650 kg/m³. It does not behave abrasively, does not cake and therefore flows very well.In our application, the product is to be loaded from a silo with an outlet of 300 mm diameter into tankers and partly also into big bags. In this case, WAM GmbH recommended a telescopic loader in the ZG design with double-walled bellows to be able to discharge the dust easily. The material falls through the inner bellows during loading, while the dusts can escape in the outer bellows. A central dust extraction system is provided for dust removal, which is why the telescopic loader is equipped with an aspiration connection. The inner and outer bellows are made of hypalon-coated neoprene, which is not only very flexible but also robust. Since product purity is of particular importance to the customer and painted mild steel is out of the question for this reason, all parts that come into contact with the product are made of stainless steel.
To prevent dust from escaping between the loader and the tanker, the telescopic loader has an attachment cone that completely seals the loader with the dome of the tanker. When the tank is completely filled, the integrated level indicator stops loading]. When the loader is raised by means of an electric winch, on which two lifting ropes pull the bellows together, a closing cone prevents material from trickling in and contaminating the surroundings.
In this configuration, a loading capacity of up to 250m³/h is possible.

Product example: hop pellets

The pellets have a bulk density of 600 kg/m³ with a diameter of 6-8 mm and a length of 30-50 mm. The material is moderately abrasive and slightly dusty. In particularly dry batches, there is a risk of explosive dust clouds forming.
The hop pellets are stored in pneumatically filled silos under which the ZA telescopic loaders are mounted on a 300 mm flange. Tankers and closed as well as open containers are loaded. With the discharge adapter, which can be attached to the hand guide ring of the attachment cone by means of quick-release fasteners, a change from closed to open loading and vice versa is possible in no time. The over 5-metre-long loading bowl contains an inner and an outer bellows as well as steel cups in mild steel for a longer service life. The 0.55kW electric winch is equipped with a spindle limit switch that measures the revolutions of the cable drum and stops the loader at the desired position. For safety, a slack rope contact additionally switches off the motor when the cone is put on.
Dust removal is provided by an integrated filter in the loader head with a 10 sqm cartridge filter that can process an air volume of 2400 m³/h. The integrated solution offers the advantage that the filtered material falls back into the bellows after cleaning the filter elements and remains in the loading process, whereas with a central dedusting system the material is collected elsewhere.
The highly flammable dusts require an ATEX version of the telescopic loader. This includes the explosion-proof design of the motors, an adapted control system and bellows in conductive material.

Product example glass powder

Glass powder, like sand in general, is one of the highly dusting and abrasive bulk materials. With a grain size of 0-1mm and a bulk density of 900-1000 kg/m³, this is a very fine material that has very good flow properties.
The basis for the customised configuration is a telescopic loader type ZG for loading free-flowing bulk materials into tankers and closed containers. Accordingly, the outlet is fitted with an attachment cone with integrated closure cone and level indicator. Due to the pronounced abrasiveness of the glass powder, WAM recommended a configuration with cups made of [Hardox] in the inner bellows. All other parts in contact with the product were also made of Hardox. For the comparatively short trunk with a stroke of 840 mm, the customer opted for a stroke adjustment by means of a manual cable winch and deflection pulley.
The loading capacity is up to 250 m³/h.

Product example: milled asphalt rubble

The material has a grain size of approx. 100 mm with a bulk density of 1300-1800 kg/m³. Asphalt crushed material is abrasive and moderately dusty. In the application, the ZX type telescopic loader is attached to a 500 mm wide flange via a conveyor belt and is intended to transport the free-flowing bulk material into ships, open trucks or containers that are sometimes much deeper. In order to be able to serve these quite different containers, a long bellows with a 5400 mm stroke and a total length of 8200 mm is required. To keep the dusts under control despite open loading, a dust skirt for the outlet was provided as well as an aspiration nozzle for connection to an on-site dust collection system. WAM recommended replacing the inner bellows with steel cups, which have a higher wear resistance to abrasive asphalt breakage. The outer bellows is made of durable hypalon coated neoprene.
In this configuration, WAM guarantees a loading capacity of 850m³/h.

Individual solutions

Individual solutions are also possible for all other bulk materials, where large quantities can be loaded safely. WAM GmbH offers loading solutions with a loading capacity of up to 1800m³/h. It is also possible to have a little more.