Mooij Agro develops and produces ventilation techniques for growers and storers of mostly potatoes and onions. The company has seen an increase in using force ventilation for open crates in recent years.
This way of ventilation, director Maarten Mooij says, is preferable over room ventilation, for instance because of the drying effect and the application of sprout inhibitors. “And the use of closed crates occurs increasingly less often because of economic considerations. That’s because the rows are limited to a maximum of ten in a row,” he notes. Within forced ventilation with open crates, it’s possible to choose between a sucking or blowing system. The choice between these systems influences the eventual storage results. Both in sucking and blowing ventilation, the air goes through the crates horizontally. “This means that even crates that are 2.4 metres wide can be well-ventilated this way,” Maarten explains. “Particularly the air distribution among the crate rows is very important. A good air distribution results in constant drying, even temperature, less loss of weight, less silver scurf and better distribution of sprout inhibitors, in other words an optimal storage result.”
Comparison sucking and blowing ventilation
While in a sucking ventilation system most of the air passes through the stacks of crates that are closest to the ventilator, causing the crates at the end of the row to be dried and cooled last, the air concentration in a blowing ventilation system is the other way around. “There we measure a lot of air in the final stacks in the row, and very little air at the beginning of the rows,” Maarten explains. “When a blowing ventilation system is used, we advise the use of a so-called inflatable airbag, which is only inflated when the crates have been put in place. This inflatable airbag is located at the top of the stack, wedged between the two top rows of crates, completely closing the opening between the crates at the top. The end of the row is closed by a vertical airbag, which gets its air through a connector in the horizontal airbag. This way, no air can escape, and the air is pressed through the crates horizontally.” Another advantage of the blowing ventilation system is there’s no need to walk on top of the upper row of crates to put the airbag in place, because it’s already hanging there and inflates itself. What’s more, according to Mooij Agro the air that’s blown through the crates is the same for all crates in the rows, causing the differences in humidity, temperature and so on to be very limited, and there’s no chance of condensation.
Every-Air improves air distribution
Field measurements by German research institute VSD have shown that both the sucking and blowing ventilation system don’t provide optimal air distribution. That’s why Mooij Agro developed a special tarp to expand on the blowing ventilation system: the Every-Air. The Every-Air works as a “brake for the air” in the blowing ventilation system, improving air distribution. This tarp is hung from the inflatable Airbags and causes a homogeneous distribution of air among the rows of crates. Tests have shown that the application of the Every-Air causes the spread in air distribution between the lowest and highest quantity of air per crate to be up to 250% smaller. Maarten: “The blowing ventilation system with inflatable Airbags, combined with Every-Air, results in even drying and cooling as well as better distribution of the sprout inhibitor, even in rows of 25 to 30 crates in a row.” For the development of the Every-Air, Mooij Agro was awarded the 2015 silver medal for innovation from AgriTechnica.
More information:
Mooij Agro
Maarten Mooij