Loading of Refined Sugar

Refined sugar (EG quality standard I) is a crystalline type of sugar obtained in high purity by means of a second crystallisation process after dissolution. This type of sugar is particularly suitable for the production of lemonades, fruit-juice drinks and nectars, confectionery and crude sugar, ice-cream, milk blend-products and many others more.

Fine sugar is provided to bulk consumers like manufacturers of confectionery or beverages (e.g. Coca Cola or Storck) and is returned to the households through additives to soft drinks, pastries etc. Also the medicinal industry requires large quantities of fine sugar.

For transport, refined sugar is mainly loaded to silo trucks and tank wagons, more seldom to open wagons.

As there are particular requirements concerning purity in both, the food as well as the medicinal sector, the loading operation has to meet high demands with respect to hygienic and quality standards. In any case, contaminations by insects must be avoided. During loading there is also the risk of dust explosions caused by emission of finest sugar powder contaminating the whole plant and finally getting lost as precious raw material. And, not least, the speed of the operation is an important factor, too, for economic reasons.

The Muhr Bulk Loading System of type MBG for closed loading meets the demands arising herefrom concerning not only economic and hygienic, but also aspects of safety-technology. If equipped with sheet metal components, rubber sealing, pneumatic blowing, double-chamber system and level indicator, the loading system offers absolutely dust-free, clean and efficient loading.

For loading an average of 25 tons of sugar per truck, the loading performance is an important factor. The Muhr Bulk Loading System of type MBG provides a maximum loading capacity of 340 t/h this is equivalent to an actual loading time of 5 minutes only, whereas loading by conveyor has a loading performance of 150 t/h.

In the initial stage of loading technology, about 10 years ago, loading of trucks and wagons was done outside as a static operation by means of belt conveyors. Lots of bees were attracted. By air nozzles or heat irradiation they tried to fend the bees off. The sugar dust led to hard cakings. For washing these off and the subsequent long drying times the complete plant had to be set out of operation on the weekends.

Today the total loading operation is done under atmospheric overpressure, so that no insects may get inside the halls when the doors are opened upon shunting. The loading sets usually freely suspended have been provided with a housing by Muhr and by that there is additional protection against insects.

In most of the loading facilities the trucks and wagons have to be adjusted before the loading operation, so that their apertures are positioned concentrically under the loading nozzle. Precious time is lost! For faster coordination during centring of the loading nozzle with the aperture, the aperture can be driven at directly by the flexible loading bellows of the Muhr Bulk Loading System. Another option is that the loading facilities are additionally mounted on a mobile unit, like in Uelzen near Ochsenfurt.

In this Muhr Bulk Loading System, the loading nozzle is shaped as a cone which is additionally rubber-coated for better sealing of the tank aperture. As soon as the loading nozzle is attached to the tank aperture, a special rubber coating with a labiate rubber seals the gap between aperture and loading nozzle and thus emission of sugar dust is prevented. This rubber coating is 20 mms thick and consists of one layer of hard rubber for wear protection, and one layer of soft rubber for optimal adjustment to the flanges of the tank aperture. When the loading nozzle is lifted, the labiate rubber docks to the sealing cone and no more residual dust particles may escape.

The sealing cone shuts off the loading nozzle´s outlet on completion of the loading and thus prevents escape of residual bulk material from inside the bellows when the loading nozzle is lifted.

Being equipped with a level indicator by an assembly system specially developed by Muhr, it is possible to increase the filling level in the tank and thus also its capacity exploitation substantially. For reducing the distance between the peak of the dumping cone and the tank aperture as far as possible, the measuring probe of the level indicator is not positioned below the sealing cone as usual, but above the sealing head and aligned upwards. By that, the signal for full-load is considerably raised. Thus, the filling level is increased by at least 400 mms. In addition, the level indicator is installed in a closed system to protect it from damages.

The slower the loading operation and the lower the pressure, the steeper the dumping angle gets and thus the ullages in the trucks and wagons to be loaded increase. The loading operation has to be stopped and the vehicles must be jerked for filling the ullages and for recharging. Recharging results in a loss of time and money for both, carriers and producers. It is not always possible to increase speed and pressure of loading. The Muhr Bulk Loading System of type MBG provides the option of pneumatic blowing: the product is mechanically distributed and the dumping angle becomes planer.

For meeting the legal regulations of safety and hygiene, a proportion of 10 mgs of dust in pure air is permitted. To obtain this, loading facilities are attached to central exhaust equipments. This is not always possible or economical. In those cases, Muhr Bulk Loading Systems with integrated filter unit and pneumatic filter cleaning in compact design offer the ideal solution.

In case of central exhaust, up to 70 kgs of material of a 25-t truck get lost between pre-weighing and final scales, as the product is returned by a conduit into the loading facilities and thus weighed again.

In the Muhr Loading System with integrated filter unit the product removing from the filter is falling back into the loading flow, it remains in the loading procedure, as the filter position is inside the bellows.

Dust removal from the filter is done efficiently and regularly by pulsing of the cleaning and exhaust procedures. By frequent cleaning in short intervals the dust remaining in the filter gets less. The homogenous composition of the sugar is kept, the ratios of dust and sugar remain in balance.

In order that less product gets into the exhaust air flow, the flow of the dumping product is separated from the exhaust section by the double-chamber system.

The exhaust range is positioned between the outer bellows and the sheet metal components serving for product guidance.

For ensuring absolute hygiene and safety, any rope guides and electric lines are outside the product flow.

In the past, Muhr Bulk Loading Systems of type MBG have proved best in loading of sugar. They are robust and fault-resistant and are distinguished by excellent cost-performance ratio and high durability.

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