Vietnam’s agriculture has been developing at a high speed, many export items occupy the position in the world market. However, the resources have not been exploited and used effectively, post-harvest losses are still quite large in terms of quantity and quality. This is partly due to the fact that our current agricultural production is still small, odd, difficult for organizations to apply technology, mechanized for post-harvest. The application of post harvest technology is weak, leading to the situation that when surplus agricultural products, agricultural producers can not switch to processing and preserving.
In the past, people used to preserve farm produce after harvest by drying the farm products through the sun, by drying on the yard, on the mulch … but this solution depends on the weather, in the sun, at The agricultural products are badly damaged, causing damage to the farmers. Therefore, many researches on drying technology and preservation of post-harvest agricultural products have been applied and applied effectively.
Drying is one of the important stages in the preservation and processing of agricultural products. There are many solutions to dry agricultural products such as cold drying, sublimation, drying by infrared ray, drying by high electric currents … Each drying technology has different advantages and disadvantages, but they are drying the form of agriculture. raw materials, pharmaceutical raw materials or deep processing.
In particular, drying to preserve agricultural products immediately after harvest to keep product quality, avoid damage, create good materials to breed for the next crop, create good materials before putting into preliminary processing Just install a wind dryer. This is defined as the reversible dryer system by the drying technology due to the hot air flow in the drying chamber to reverse operation to dry product evenly without need.
Usually the dryer has the following main components:
Heaters: Can use charcoal, firewood, chaff or use electric heater.
Fan: usually uses axial fans, centrifugal fans to provide the required flow and pressure for horizontal driers.
Wind coil and drying chamber: drying chamber, drying chamber, usually made of iron or stainless steel, is punched 2-4mm depending on the size of agricultural products distributed evenly on the blister.
The top structure of the machine is the lid of the oven.
Operation of agricultural dryer
After heating the furnace, the hot air is mixed with fresh air to reach the set temperature. Axial fans bring standard hot air into the drying chamber according to the structure diagram with the flow and adjusted speed of the fan.
The first stage of the hot air is fed through the farm layer from the bottom of the drying chamber. The produce will be dried upwards, the hot air brings moisture up and out.
The second stage of hot air is distributed to the level from the top of the drying chamber, the wind blows through the layer of farm products to be dried.
After a reversal, the farm produce is dried to the required temperature with high uniformity at all positions in the oven. The remaining moisture is about 12-13% the cup.