麻豆社

Summary: Silos are storage facilities in mechanized bulk material handling systems, mainly functioning for intermediate storage, system buffering and operation balancing...

What are silos?

Silos are storage equipment in mechanized bulk material handling systems, mainly serving for intermediate storage, system buffering and operation balancing. The silo devices consist of feed inlets, silo top, silo body, cone bottom, reinforcing ribs, lifting lugs, manholes and discharge ports, as well as control, metering, distribution, mixing and dust removal systems.

Function of silo in aggregate production plant

In aggregate production plant, silo is a very important part, which plays the role of transfer, buffer and adjustment. In the production process, to ensure the continuous, uniform, and smooth feeding of raw materials, and to ensure the maximum volume, to prevent the accumulation of raw materials at dead corners, the design of silo must be reasonable.

Classification of silo

In a stone crushing plant, silos can be classified into raw material silos, adjustment silos and product silos.

Raw material silo is generally square cone-shaped, enclosed on all sides, and welded by steel plates. It is generally used before the vibrating feeder. The size of the raw material silos are designed according to the processing capacity of the primary crusher and the viscosity and humidity of raw materials. Generally, raw material silos are located on the ground.

Adjustment silo

Adjustment silos are generally made of steel frame structure or reinforced concrete pouring. It is located after the primary crusher and before the secondary or fine crusher. The main function of adjustment silos is to transfer and regulate crushed raw materials from the primary crusher. They can realize uniform and stable feeding, improve the efficiency of the crushing production line, and extend its service life.

Product silo

The style of product silos is more like a rectangular workshop; partition walls are used to separate different products to achieve product grading.

How to design the silo? What kind of silo is reasonable?

Design of raw material silo

For feeding module, we should select the platform feeding or the silo feeding according to the site conditions and the ratio of raw materials. Platform feeding relies on height difference to provide gravitational potential energy for raw materials, allowing large stones to pass through naturally and enabling preliminary separation of natural sand. However, it requires favorable terrain to build a high platform for raw material feeding. By contrast, silo feeding requires pit excavation and construction. Raw materials poured into the pit are transported to the production workshop by the conveyor belt. Compared with the platform feeding, this form needs less investment cost and is convenient for construction. However, it cannot handle too large stones. If there are too large scaled stones or too sharp stones, it may cause damage to the raw material transportation belt and affect the production schedule of the entire production plant.

Design of adjustment silo

For production lines with large changes in raw material composition, such as river pebbles, it is very necessary to set up adjustment silos before the medium crushing stage. The size of the silos should generally be sufficient to store aggregates enough for the crushing equipment to operate for 2 to 3 hours. Due to the large variation in the composition ratio of river pebbles, transfer buffer silos are arranged in the process to buffer sudden load increases or idling of crushing equipment caused by excessively high sand or pebble content in certain batches of raw materials, so as to ensure stable equipment operation.

Design of product silo

Product silos are mostly rectangular in structure, with partition walls used to store different finished products separately. High concrete retaining wall is recommended for partition. The crushed products are conveyed to the corresponding area by belt conveyors and can be piled directly against the wall, greatly increasing the storage capacity of finished products in the silos and making full use of space while saving investment costs. At the same time, the loading space of product silos should be enlarged as much as possible to facilitate loading operations and reserve sufficient buffer areas for material stacking.

Common problems and solutions in silo design

Feeding silo for coarse crushing

The common problem of feeding silos for coarse crushing is that their side discharge ports are designed in a rectangular form, resulting in dead corners between the silos and the discharge ports. The raw materials cannot be fed smoothly, and large-sized rocks tend to accumulate here, disrupting normal feeding.

There is a simple solution to solve this problem: place an excavator next to the feeding port to clean up the accumulated material at any time.

Buffer silo for medium-fine crushing and sand making

The common problem of buffer silos for medium and fine crushing and sand making is that they adopt a flat-bottomed steel silos structure at the bottom. Due to the high overall material pressure on the bottom of the silos, severe deformation and settlement of the steel silos bottoms may occur during production line operation, posing potential safety hazards.

To solve this problem, we can reinforce the bottom structures of the silos. While designing the silo, try to avoid the use of flat-bottomed steel silo structures. When it is unavoidable to choose a flat-bottomed silo structure, try to choose a concrete structure at the bottom of the silo.

Product storage silo

Product silos generally adopt concrete silos, which feature large storage capacity, safety and stability. However, some companies choose steel silos to store sand and gravel aggregates. These companies should regularly inspect the wear of steel silos and perform anti-wear treatment.

Stone powder storage silo

A common problem of stone powder storage silos is that stone powder absorbs moisture on rainy days, adheres to the silo walls, and becomes difficult to discharge. To solve this problem, operators can install several air cannons under the silos and use compressed air to loosen stone powder inside the storage silos. The design department should avoid excessive stone powder storage volume, and install flow-aiding plates, inflation boxes or air cannons on the silo cone section during design.

In production, on the premise of ensuring continuous crushing operation, silo design should make full use of layout space. New design methods such as dual control of the inclination angle of the slope and the edge angle relative to the horizontal plane can be adopted to eliminate material accumulation in dead zones.