Assuring grain quality in storage

09 July 20215 min reading

“Temperature monitoring and ventilation are central elements in assuring storage grain quality. To manage temperature and moisture, ventilation has become the main tool to improve extended grain storage. It requires a multifaceted approach, balancing readings of humidity and temperature, both inside and outside of the silo.”

Alfonso Garrido CEO Symaga

For the grains and bulk logistics industry, a metallic silo is a proven system to improve grain quality and preservation. Steel silo is the top investor-friendly asset thanks to its many advantages: it can hold large capacities in the space available; it is an economical solution, with easy-assembly and easy-maintenance; the automation for loading and unloading reduces OPEX and labour costs, etc.

Regarding grain quality preservation, steel silos allow for a better post-harvest management, with less losses and major quality improvements, due to humidity and temperature control, ventilation, as well as it is effective against damages from weather events, rodents or insects.

Temperature monitoring and ventilation are central elements in assuring storage grain quality. It requires steady vigilance from the first load of grain – checking the material’s temperature and humidity. Silo managers understand these two variables, and their setting, will determine the options for storage time, and will directly prevent the appearance of pests or molds. Pests are one of the main threats to stored grains, which find hot, moist environments ripe for breeding. Same applies to molds and fungi, that can contaminate and throw to waste an entire stored crop.

To manage temperature and moisture, ventilation has become the main tool to improve extended grain storage. It requires a multifaceted approach, balancing readings of humidity and temperature, both inside and outside of the silo. To put it simply, ventilation moves air form the outside, with the right moisture and temperature conditions, to keep and maintain the grain inside to our target of humidity and temperature for long term and quality storage.

Working at unison with ventilation, a temperature monitoring system allows for the control of the temperature over stored material and storing conditions. It is composed of a set of probes hanging from the roof inside of the silo, providing real-time readings of temperature and, for advanced systems, moisture, across the silo grain column. Normally these are passive systems, with zero maintenance, and in some cases, the probes are designed to be replaced without emptying the silo. Symaga offers a temperature monitoring system and an aeration system that meet our customer’s most demanding requirements, and cover all their grain storage needs.

From top to bottom, a full system is composed of, first, roof vents, that allow free flow of air and allow for air renovation. Symaga’ circular design prevents the accumulation of water or snow, it is easier to assemble, embossed with the roof section, and it comes with anti-bird net. Some are design to be shut for fumigation activities, and ready for the installation of an extractor fan to avoid condensation inside. Down to the silo base, different aeration designs allow for the ingress of the air inside the silo. The most common is the channel-type, made up of concrete-casted channels covered with galvanized, corrugated and multi-perforated boxes, covering between the 25% and the 30% of silo bottom. Channels come in different shapes, commonly known as “Y”, “H”, “C” if silo has a concrete hopper, or “T” if it is a hopper silo. To ease the civil works of the silo foundation, Symaga also supplies galvanized prefabricated gutters. Alternatively, fully-perforated floors, supported on steel structures, cover the entire silo base and allow for a most homogeneous entry of air – which is key for some grains, such as paddy rice.

One development that allows for aeration and easier handling are the Ventilated cone. It is comprised of an elevated cone made of galvanized steel inside the silo. The system avoids contact between the ground and grain, making civil works and operations cheaper, while increasing the area of aeration

Depending on the type of grain, it is important to select the right type of perforation of the aeration plates. Symaga supplies the plates with perforations of 1- or 1.5-mm diameter.

Finally. The major element in aeration is the fans, that are going to bring the air inside of the silo and help us module the temperature and moisture contents inside of the silo – and outside, in the case of the extractors embedded in the roof vents. In Symaga, our fans have IE2 certification, ensuring energy efficiency, and capacities range from 2 hp to 30 hp, depending on the customer’s needs. Other elements that are bringing great solutions for storage are grain chillers. These improve grain preservation markedly, as lower temperatures create a hostile environment for pests and fungi, thus avoiding fumigation, and at the same time help to minimize grain weight loss. While they require a significant investment, chillers come with great advantages for grain management, as their operation is independent from the weather conditions outside of the silo.

Steel silos were developed alongside with the mechanisms to manage temperature, humidity and ventilation, as a valid and proven option effective in improving quality grains, while underpinning protection from pests, improving food security, empowering smallholder farmers, enhancing income opportunities and job creation, and safeguarding the agro-ecosystems.

With projects delivered in over 145 countries, 42 million m³ built, 10,000 projects, 35-plus years of experience, and the integration of our silos in the biggest storage projects, SYMAGA has a consolidated role as a major, reliable manufacturer in the industrial silo sector. Tailored technical support to each project and state–of-the-art facilities make SYMAGA your best partner for storage.

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