SILOS

SILOS

It is obtained from a Greek word – silos which means ‘’pit for holding grain’’. Silo is used to store materials in huge amount such as grains, cement, coal, carbon black,etc. Since different industries use silos for different purposes hence many different conditions need to be undertaken while deploying them and get the most out of them. Mostly stored items are either solid or in powder forms.

CONSTRUCTION

Generally, one can easily find cylindrical shaped silos with a metal support although there exists rectangular and square ones also. They can be built with a metal, stainless steel, reinforced concrete, wood, reinforced plastic, etc. The interior of silos is generally smooth and has a special coating inside. Also. During construction of a silo, the amount of product to be stored in it, location, weather conditions as environmental factors such as temperature, humidity are also taken into account.

CLASSIFICATION

Depending on the raw material to be stored

1. Tower silos

• Most common structure.

• Approx. 4 to 48 meters in diameter and 3 to 40 meters in height.

• Constructed using wood, cement, steel or concrete.

• Heavy transportation such as trucks, rail cars are used to unload the silos. 

2.Bunker

silos

• Usually made of concrete walls

• It is made airtight via a plastic top covering

• Usually unloaded with a tractor.

• Bunker silos are preferred when one needs to store material in very huge quantity such as in agriculture industries. 

• Nowadays, even military is using bunker silos in order to store and handle the missiles.

3. Bag silos

• They have bag or tube-like structure. 

• Used to store grains and fodder in the field

• Length generally depends on the material amount to be stored but average diameter is 2 to 21 meters.

• These are most economical. 

• These are very heavy and is sealed from both the ends in order to protect the material from slipping out of the silos. 

Advantages

 Even tons of materials can be stored easily in silos in comparatively very lesser space than the ground.

 Optimal conditions are maintained in silos so that the stored material is safe.

 The cost of storage in silos is much lesser than any other storage systems.

Disadvantages

 A lot of risks are involved in using silos for storage like-

o The risk of fire and explosion

o Risk of poisoning

o Risk of intoxication due to excessive use of chemicals like pesticides

o Risk of suffocation due to accumulation of excessive carbon dioxide.

Safety

To protect the silos from all the above-mentioned risks, all the mandatory safety measures needs to be undertaken while loading and unloading silos.

Robots and machines are used to perform this job of loading and unloading silos in order to prevent the humans from unwanted accidents and avoiding the need to climb the silos for storing the materials.

Grain Silos

For the sake of storing tons of grains and protecting them from unfavorable weather conditions, grains silos are used. 

Every country keeps some amount of grain as storage in silos in order to use it in case of extreme unpredictable conditions such as famine, flood, earthquake, etc.

Classification

For grain storage three type storage styles preferred –

• Brick warehouses – used by small scale industries

• Spiral sheet silos – mostly preferred

• Reinforced concrete silos

Steel silos were originally originated in 20^th century and were used by Europe and America. They proved their success by removing the granaries and become the sole method for storage in developed countries such as US, and Canada in the very early years of its introduction to the world.

It is highly preferred till today because of its low construction cost, small floor space and small construction period.

Advantages

• Thin walled so that there is very less temperature difference between outside and inside environment. Various kinds of ventilation technologies are used such a radial, horizontal pipe, etc. in order to maintain favorable conditions inside the storage units. 
• Outside air and the internal air keeps on circulating to maintain the freshness in the material
• The temperature of the silo is controlled electronically.
• Since steel sheet has the capacity to absorb heat so it gets intensely hot inside due to the high temperature outside. So, to protect the materials from such extreme temperature conditions cooling technologies are used inside the steel silos to protect the products from ruining.

Safety

• As a matter of safety and security of food stored in silos, regular inspection must be done and factors such as temperature, ventilation, storage, etc. must be undertaken. 
• On an average, grain silos can store grains for approximately 3 years. 

Cement silos

These are used to store cements in cement processing units, production industries, etc. 

Construction .

Generally, it is cylindrical in shape with four legs. A dust collector is fixed at the top of silos to prevent pollution and loss of, material with the dust.

Safety & Maintenance

• Since everything require maintenance, similarly cement silos also need maintenance for the good health of cement stored in them.The material is discharged through discharge point, so it necessary to ensure the smoothness of the output port. 
• Air leakage should be checked prior to the storage of cement.
• Only dry cement should b stored in the silos or else the bigger stronger lumps formed would clog the discharging pipes.

Difference between cement and grain silos