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Portable grain dryers: better direct flame or indirect flame?

 
30/09/2022

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As early as the 1980s, but increasingly in the 1990s, the need to process organic and organic grains with systems capable of preserving all their organoleptic characteristics was confirmed. To meet these new needs of farms, Mecmar designs and manufactures portable direct-flame and indirect-flame grain dryers. It is precisely the latter system-the indirect flame system-that is the most suitable for processing grains intended for organic and human consumption.

But how do the two solutions differ and which portable grain dryer turns out to be the most suitable for your reality? The Mecmar team explains it to you: continue reading to learn all the details or, if you're short on time, watch the video at the end of the article!

Direct vs. indirect flame: which process best meets your drying needs?

Portable grain dryers with direct flame are certainly the most popular and widely used on the market. In this case, the grain processing process involves the use of gas or diesel as a fuel source, so as to ensure even and uniform grain drying.

But what is the process that takes place inside the cylinder of the direct flame dryer? High volumes of air are mixed with the products of combustion: thus, the quality of the air used to dry grain depends on two factors. First, the quality and type of fuel used to generate hot air inside the dryer. Second, the success of the process is related to the correct burner calibration.

In addition to this, in order for the drying phase to return a dry and clean product, it is a good idea to regularly check that the combustion chamber is functioning properly and is free of any residual dust. Specifically, before starting the drying phase following a downtime, be sure to perform effective grain dryer maintenance. Read the dedicated article to learn more.

Introduced relatively recently, the indirect flame drying process makes it possible to meet the ever-increasing demand for certifications that guarantee high quality grain. Normally, portable indirect flame grain dryers are fueled by diesel fuel, but the real heart of this revolutionary grain processing system is the heat exchanger.

The very latter ensures that no combustion products come into contact with the grain being dried. Thus, on the one hand, the nutritional properties of the grains are preserved and, on the other hand, a clean, environmentally friendly and natural product can be obtained, which fits perfectly with the standards required to acquire certifications and labels attesting to its quality.

Equipped with a large number of noble steel tubes, the heat exchanger ensures high drying efficiency and minimal consumption, especially when compared with the performance of the direct-fire system. In fact, the air drying the grain inside the indirect-flame system draws heat from the combustion products, which are then emitted directly into the atmosphere without mixing with the grain.

When to choose a direct flame system and when to choose the indirect flame system?

Usually, portable direct-flame grain dryers are used for general drying purposes. Since the combustion chamber of the system is insulated by a cushion of cold air, the solution guarantees 100% efficiency for all users. All the heat produced by the burner is transferred to the grain, since there are no hot parts of the dryer to retain it.

The heat essential for drying is not dispersed, but transferred to the grain inside the cylinder containing it. Finally, the compactness of the system results in lower purchase costs and easier maintenance.

When, instead, to choose a portable grain dryer with indirect flame? In this case, given that the air being dried is completely clean, the system is mostly used for drying organic grains for human consumption. Technologically more advanced, in a Mecmar indirect flame plant, the exchanger is separate from the cylinder containing the grain, minimizing risks. In fact, the plant is the result of years of testing and trials to ensure the best efficiency and durability for the end user.

Below you will find other interesting insights about Mecmar solutions for drying and roasting grains:

Do you have additional questions about how direct-flame vs. indirect-flame systems work? Would you like to talk to one of our experts to find out which solution is best for you? All you have to do is contact us: the Mecmar team will be happy to answer all your questions.

Watch the video to get a quick overview of the differences between direct and indirect flame:

https://www.mecmargroup.com/en/lp/calcolatore-costi-essiccazione
https://www.mecmargroup.com/en/lp/calcolatore-costi-essiccazione

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