What is a Silobag?
A polyethylene bag, usually of 60 meters long and 2,74 meters in diameter for storing all types of grains. It is suitable for storing commodities (wheat-up to 200 MT, maize, barley, paddy, oats, sunflower, soybean, rapeseed, mustard, and others), forage and fertilizers in the open field.
It is made of laminated sheet formed of 3 layers of coextruded polyethylene. The first 2 layers are white and make the bag water proof and act as a filter for Ultra Violets and the third layer is black and protects the grain from sunlight.
How does a Silobag protect the grains?
The bag is sealed and airtight and it is designed to stretch by 10%, ensuring that the grain is packed tightly and that most air is expelled at filling. Once the grains are loaded in the bag and the bag is sealed, they consume the available oxygen, generating a modified atmosphere rich in carbon dioxide which ensures an optimum conservation.
This steady atmosphere, together with the thermal protection offered by the special material, prevent the increase in grains temperature, preventing the development and proliferation of fungi and insects, common in traditional storage systems.
How is a Silobag filled?
With a specially designed bagging machine which can be filled from a self-unloading hopper, a combine or any high volume auger. Common bagging machines have a capacity up to 200 MT per hour, can be easily transported and need tractor with a minimum power of 33 kW (45 HP), with PTO shaft speed of 540 rpm and hydraulic output.
It can be handled by one operator and can keep up working along 3 combines without stopping and forgetting about having to stop the process due to lack of trucks, a very common problem during harvest season everywhere.
How is a Silobag emptied?
By using a specially designed unloading machine which opens the bag with a cutter and lifts the grain to a self-unloading hopper or a truck. Common unloading machines have a capacity up to 150 MT per hour, can be easily transported and need a tractor with a minimum power of 33 kW (45 HP), with PTO shaft speed of 540 rpm and hydraulic output.
Self-unloading hopper – a crucial partner
This machine is used for the transportation of the grains from the combine to the place where it will be stored. It must have a quick and practical un-loading system so that it would allow them to come back as fast as possible next to the combine and wouldn’t lose efficiency during harvesting process. The hopper allows increasing labor capacity of the combines and, at the same time, it can load trucks or bagging machines.
Where are Silobags stored?
In the open field, on any clean and well drained ground that is free from sharp objects and does not have too steep inclination. This can be even a harvested field as long as the crop stubble is not too sharp. It is also recommended to apply a chemical treatment to control the weeds/grasses around the perimeters of the bag.
When placing the bags in the field, it should take into consideration that the bags would be far from trees and any other possible source of breakups.
How much ground is needed to store gain in Silobags?
There is no limit of grain that can be stored in silo bags, only available land. Depending on the grain, up to 500 square meters are needed for one bag. There are so called silobag „parks” in South Africa which have been holding more than 50.000 tons of grains and in Sudan which have more than 200.000 tons.
Inside the Silobag
All grains should be stored at the „normal” standards. For example, wheat can be stored safely if has below 14% moisture, but can also be stored above 14% moisture for shorter periods. If moisture level is within recommended limit, grains can be stored with no problem in the silobag up to 24 months.
The bag is an airtight environment, anything alive (insects, fungi) and grains consuming the limited oxygen in the bag and expelling carbon dioxide. Usually within 30 days, the oxygen volume in the bag drops from 20% to 3% and the carbon dioxide volume rises from 0% to 17%, the inside of the bag becoming anaerobic.
A damaged Silobag can be repaired?
Minor damages can be repaired with a special duct tape, but major damages require to unload and re-bag all the grains in the section with the problem. Undamaged sections can be resealed.
Constant visual inspection of the bag is required in order to prevent any possible damages to the commodities insides the bag. Modern technologies made possible manufacturing of special equipment for monitoring the levels of carbon dioxide, oxygen, temperature and moisture which offer the possibility to control the grains’ quality from bagging to the final sale.