Silo

A silo ( of or from Spanish: silo ) or silo is a large storage for bulk materials. Silos are used to store cement, limestone, plastic pellets, feed, and the like.

Function

Silos are generally filled from the top and removed from the bottom. Nevertheless, they do not work on a first- in-first -out method. Rather forms when pin through the lower lying outlet a funnel in the goods passes from the different filling layers and as a mixture of an earlier time and later filled into the silo quantities exits. The product tapped through the outlet port so it is a mixture of all quantities in the silo.

For this reason, it is in the case of Silofalschbefüllung be avoided as thoughtlessly from below to tap into the mistaken assumption that the mismatched filled product remains on the previously correctly loaded into the silo top and will only emerge in time for him. It is useful in such a case to try to extract false top added overloaded product from above by means of suction or the like out of the silo. In the commercial arena, a surveyor is consulted with professionals experienced in such a situation often.

Depending on the material is sufficient for withdrawing a spool or if gravity is not sufficient to cause the material to flow, a mechanical conveyor such as a screw conveyor.

Physics

The pressure conditions in a silo promote a relatively light construction compared to the same high tank for liquids. While in a tank of the horizontal pressure increases linearly with the height increases from the top to the side walls downward, the increase in the silo takes place much more slowly, that is only proportional to the logarithm of the magnitude. The exact calculation of the pressure in the resting state of the stored material is possible with the Janssen equation. A problem is posed by the forces occurring during emptying, as these are not considered by Janssen and can lead to damage of the silo. Technical bulk experiments, such as shear tests on bulk material to be stored, are therefore essential.

Hazards

In agricultural silos, the risk must be considered by itself -collecting Silogas. Before entering the silo, the Silogas must be removed by ventilation, otherwise there is acute danger of suffocation.

Designs

Common types of silos are round silos, square and Achtecksilos. Vielecksilos have the advantage that they are manufactured in modular construction and subsequently modified assuming a suitable steel construction (magnified) can be. By such a modular design can large volume silos that would no longer be transported with a truck in the final state can be easily and inexpensively transported. In agriculture silos, about 10 to 20 meters tall cylindrical structures made ​​of concrete, stone, steel, wood or plastic, in which grain or silage is stored, disseminated. There are also exceptionally high silos as the Henninger -Turm in Frankfurt or the granary of Schapfenmühle in Ulm, which are over 100 meters high. These structures are called silo tower.

For the preservation of forage resources in agriculture silos were largely replaced in recent decades by the work economically favorable silos. These comprise a base plate and have side walls. If the silage stored only on a base plate or without a fixed base plate, one speaks of a Freigärhaufen. The top cover is usually done by an airtight plastic tarp that is weighted down usually with tires or sand bags. To protect against damage to the plane, a bird screen is usually used yet. Silos are loaded by loading wagon with chopped fresh or angewelkter biomass, which is evenly distributed, compacted and covered airtight. The removal is usually done with special equipment on the tractor ( Siloblockschneider rear-mounted tractor, silage cutter on the front loader ). For silage and storing vegetable fermentation substrates for biogas production also silos are used.

In agriculture, flour mills, bakeries, but also in industry for many years textile silos, also called tissue silos used. The capacity of such silos can be up to 50 t per unit. Due to the " flexible " construction sizes of up to 300 cubic meters are possible. In recent times, such silos are often used for storage in pellet.

In the construction industry ready-mixed mortar is delivered for plastering in mobile silos. These silos are usually coupled directly to the mixing plant.