Once the Grain silo installation is complete and you are ready to fill the silo with grain for the first time, you always wonder how to go about it? What checks needs to be performed and what precautions needs to be taken as grain silo is your most expensive strategic long-term investment and you never want to go wrong at any step.
You are afraid of grain spoilage inside silo. You are majorly concerned about sanitation, checks and prophylactic treatment that must be conducted to ensure that grain quality is maintained without any deterioration.
Besides, Silos might have design errors, construction errors and also utilization errors that may lead to a Silo Collapse. Silo collapse are extremely dangerous and can result in human fatalities, severe injuries, loss of plant and machinery besides operational downtime.
Let us discuss everything step by step and understand all necessary precautions and checks that one must take to ensure that nothing will go wrong and quality of grain inside the silo remains intact without any further deterioration
1. Sanitation of Silo Complex Area
Sanitation essentially means cleaning, disinfecting and sealing activities performed at silo facility to make it insect or bug free. The goal of sanitation is to eliminate insect eggs, pupae, and adult’s population.
The first thing that we must do is to remove all vegetation and weeds around silo and make the area completely weed free. Clear all grain spillages and dust accumulations from silo complex. Use shovels, brooms, and industrial vacuums to clear dust, webbing, and fines from around any cracks and crevices, doors, seams, vents, etc.
Besides, clean and disinfect all grain receiving equipment like weigh bridge, truck tippler, dumping pits, conveyors, elevators, cleaners, bulk weighers, dust extraction system an, structures etc. wherever bugs are expected to grow as bugs from these areas may get conveyed to main storage silos.
Disinfect everything with allowable pesticides / disinfectant.
2. Sanitize Grain Silos from inside and outside before refilling
Seal all gaps / cracks / crevices like silo bottom, manhole, unloading hoppers, side door, eves, horizontal & vertical sidewall sheet seams and damaged sealing washers etc. to prevent moisture / bug entry inside silo.
Clean all equipment like Sweep Auger, Unloading Hoppers, and Manholes, vents, fans, perforated sheets, aeration ducts and walls of Silos before loading the grain into the Silo. Incase any portion of Silo wall is found rusted it must be painted with food grade white paint before filling silo with grains.
Finally, pretreat clean silos also from inside and outside with an allowable grain protectant / pesticide.
3. Silo Inspection
Newly installed Silo must undergo a thorough inspection to make it ready for loading.
Conduct the free run of Sweep Auger to ensure that sweep auger is in good working condition and then Park the sweep auger at designated place so that it is visible from the sidewall inspection manhole. Check that all the perforated sheets are flush levelled with the silo floor and not obstructing smooth movement of Sweep Auger. Silo floor too should not be uneven or sudden level changes or else it may not allow sweep auger to move freely.
Tie all the temperature cables of the temperature monitoring system with fishing twine which can withstand a load of around 15 Kgs without breaking. Also check if all sensors of temperature cables are transmitting temperature signals to remote console.
De-seal all manual and motorized vents in case they are sealed for fumigation and check if motorized vents are operating properly and are fixed with bird mesh. Close all sidewall and roof manholes / inspection doors properly. Close all discharge gates after checking their operation. Finally check if High Level prove is working properly.
Once all above activities are completed Silo is ready to be loaded.
4. Grain Cleaning and Drying
Once everything as said above is ready and silos are ready to be loaded with grains the next important step is to dry and clean the grain. All grains must be dried to bring them to safe moisture content before loading them into the silo for long term storage. Most of the grains can be stored safely at moisture levels between 12% to 13%. However, fast drying of grain must be avoided as it makes the grains brittle and eventually breaks them.
Grain must be cleaned of all impurities before loading it into Silos. Pass all the grain through Aspirators, Magnetic Separators, Rotary Drum Sieve and Grain Cleaner to make it clean. Operate conveyors and elevators at lowest possible speed so as to avoid the breakage of grain. Besides, one must never put newly harvested grain into a silo containing old/bad quality grains. It is essential to empty the silo and cleaning it thoroughly before refilling it with new grain.
Grain quality checks must be performed on all the grains before transporting them to Silo for long term storage. Screen for Mycotoxins too. It always gives you more confidence about storability of grain when you know the weighted average quality grains inside a silo. Moreover, It is also advisable to weigh the grain after cleaning with online dump scales so that you know much quantity you have transported to grain silo.
5. First Fill of Grain Silo
When the silo is ready to be loaded after taking all the precautions as stated above one final inspection of Silo structure must be conducted for any visible structural damage / deformation / discrepancy.
A new silo must be loaded in 4 stages. In the first stage load silo with 60%, of the total storage capacity. After loading conduct inspection of silo structure for any visible structural damage / deformation / discrepancy.
Thereafter go for 75%, loading, 90% loading and then finally 100%. Loading. After achieving each stage, it is advisable to unload at least 2% grains from the silo and fill it back into the silo so as to check that silo can withstand the additional pressures that grains generate during its unloading from silos. However please note that grains should be discharged only from the central unloading gate. Besides if possible, keep a gap of one or two days in between each stage for soil settlement.
A thorough inspection of silo structure after each stage must be carried out for any visible structural damage / deformation / discrepancy. In case any visible structural damage / deformation / discrepancy is found at any stage the further loading must be immediately stopped as any further loading may result in silo collapse.
While loading multiple silos having common tunnels, it is always advisable to complete 1st Stage loading for all the silos before initiating for 2nd stage loading and so on. This loading pattern is followed to avoid unequal settlement of the two silos which may lead to tilting of one silo.
6. Silo Loading, De-Coring and Levelling of Silos
While loading Silos always avoid overfilling of silos as overfilling reduces head space and results in more condensation / crusting which eventually result in grain spoilage. It also makes it difficult to monitor the grain condition. Grain loading into silo must stop immediately once level of grain at the eves reaches 4” below the top eve height.
Once the Silo is fully loaded, we must De-Core the silo to remove fines accumulated at the center of grain mass inside silos. This activity is very important to ensure the efficiency of aeration process. De-Coring process is carried out by discharging 2% grain from the central discharge gate of the silo and reloading it into the same silo from top.
The final activity after de-coring is Levelling. Levelling means flattening the heap on silo top to level the stored grains inside silo. Levelling is carried out by unloading extra grain that is forming heap inside Silo. We must level the grain inside silo as early as possible after the harvest to facilitate trouble-free long-term storage of grain.