What is a convection dryer? Operating principle, structure and advantages of the machine

Convection dryer is an indispensable equipment in the food, agricultural and pharmaceutical processing industry. With the ability to dry effectively and preserve product quality, convection dryer is increasingly popular and widely used.

So what is a convection dryer? How does it work? What components does the machine consist of and why is it considered the optimal solution in the drying process? This article will provide a comprehensive view of the convection dryer, from the operating principle, structure to outstanding advantages, helping you better understand this important equipment in the food processing industry.

What is a convection dryer – Modern drying technology

SUNSAY convection dryer is a specialized equipment that uses the principle of hot air convection to dry foods, agricultural products, and medicinal herbs. The machine operates by creating a continuous flow of hot air circulating in the drying chamber, helping to remove moisture in the product quickly and effectively.

Thanks to this technology, SUNSAY convection dryer not only preserves the color, flavor, and nutritional value of the product but also reduces drying time and costs.

Convection dryers  are designed with different capacities, from small ones for families or small businesses to industrial models capable of drying tons of raw materials per batch. With drying trays made from high-grade 304 stainless steel, easy to disassemble and clean, along with an intelligent automatic control system, the machine ensures safe, efficient, and energy-saving operation.

What is a convection dryer – is an ideal choice for businesses and households that want to improve the quality of dried products, while optimizing production processes and minimizing costs.

What is the working principle of convection dryer?

• Convection dryers use a heating element (usually an electric resistance bar or gas heater) to heat the air. The temperature can be adjusted depending on the type of product to be dried and the specific final moisture requirement.
• The convection fan blows hot air into the drying chamber and distributes it evenly through the product trays. The hot air moving through the product helps evaporate water from the surface of the material to be dried.
• As the air moves through the product, it absorbs moisture from the product, which is then either exhausted or recirculated through the heating system to increase efficiency.
• When the hot air comes into contact with the product surface, heat energy is transferred from the hot air to the product, causing water vapor to evaporate. This water vapor is carried out of the drying chamber by the air flow through the ventilation system.
• This process continues until the product reaches the desired moisture content.
• Convection dryers are often equipped with temperature and time control systems, helping users easily set appropriate drying parameters for each type of product.

Advantages of convection dryer

With lower equipment and operating costs compared to other drying methods such as freeze-drying or freeze-drying, convection dryers are an economical choice for many businesses.

The machine is designed to be minimalist, easy to use and maintain, helping users quickly get acquainted and operate, while minimizing maintenance time and costs.

The machine is capable of drying a variety of products, from fruits, vegetables to medicinal herbs, meeting many different production needs in the food and agricultural processing industry.

What are the factors affecting the convection drying process?

• Drying temperature: The higher the temperature, the faster the water evaporation rate, but care must be taken not to exceed the maximum heat-resistant temperature of the product to avoid loss of nutrients, discoloration, and flavor changes.
• Airflow: The airflow should be strong enough to carry away moisture but not so strong as to damage the product.
• Product layer thickness: The thicker the product layer, the longer the drying time. Therefore, it is necessary to adjust the thickness appropriately to ensure the drying process is effective.
• Air humidity: The lower the air humidity, the better the moisture absorption capacity, so the drying process takes place faster.

What is the structure of SUNSAY food dryer?

Machine housing:  Also known as the body, is usually made of stainless steel or powder-coated stainless steel, with high durability and good oxidation resistance. This material is also easy to clean and does not attract dirt, ensuring hygiene and safety during the drying process of raw materials.

Drying tray:  Usually made of stainless steel or powder-coated stainless steel, capable of withstanding high temperatures during the food drying process. Normally, the drying tray is designed in a mesh form to effectively remove moisture from food during the drying process. The number of drying trays depends on the size and operating capacity of the machine.

Drying chamber:  Located inside the machine housing and contains the drying tray system and other components. The drying chamber is designed with good insulation thanks to the use of glass wool around the machine wall, helping to retain heat and prevent heat from escaping to the outside environment. This ensures that the temperature inside the machine is always stable to dry food and save electricity.

Insulation and heat-resistant part:  An important component of the food dryer. Usually a layer of glass wool is attached around the machine, which has the effect of insulating and maintaining the temperature inside the drying chamber. At the same time, it also prevents heat from escaping to the outside to save electricity.

Control Panel:  Home food dehydrators usually have simple control systems. However, food dehydrators are upgraded with control panels that allow the user to set and control the machine, including operating modes and time. The control panel can be electronic or mechanical, depending on the design from the manufacturer.

Cooling system:  Includes fans to reduce heat from the food drying process. The dryer always maintains a stable temperature, avoiding overheating that causes damage and reduces the life of the machine.

Heating system:  Works in reverse of the radiator system. This part is located near the radiator system. In case the dryer loses temperature or does not reach the set temperature, the heating system will work in coordination with the radiator system to increase the temperature in the machine. This ensures maximum drying efficiency.

Applications of convection dryers in agricultural production

• Drying fruits and vegetables: Convection dryers are widely used to dry fruits such as mangoes, bananas, apples, and pineapples, as well as vegetables such as carrots, potatoes, and mushrooms. The drying process helps to extend the shelf life, retain the natural flavor, color, and nutritional value of the product.
• Drying of seeds and grains: Convection dryers are also used to dry seeds such as beans, peanuts, cashews, and grains such as wheat, rice, and corn. Drying helps prevent mold, prolongs storage life, and maintains the quality and nutritional value of the seeds.
• Drying medicinal herbs and spices: For medicinal herbs and spices such as ginseng, ginger, turmeric, tea leaves, and dried flowers, the convection dryer helps preserve the valuable active ingredients and essential oils in the product, while ensuring the quality and natural aroma.
• Drying processed foods: Convection dryers are also used in drying processed foods such as vermicelli, noodles, and tofu products. The drying process helps the product retain its crispness, toughness, and characteristic flavor.

• Seafood drying: In the seafood processing industry, convection dryers are used to dry fish, squid, shrimp, and other seafood, helping to prolong shelf life, retain freshness and nutritional value.
• Drying flowers and flower buds: Use a convection dryer to dry flowers and flower buds such as roses, chrysanthemums, jasmine, for making tea or for use in the cosmetic industry. The drying process helps preserve the natural fragrance and bright colors of the flowers.
• Drying organic agricultural products: In organic farms and production facilities, convection dryers help dry products such as green tea leaves, coffee, cocoa, to process into high quality final products, meeting export standards.

Convection dryers provide an efficient, economical and versatile solution for a wide range of products in the agricultural industry, helping to improve the quality and increase the value of post-harvest products.