Steam Coils for A Tunnel Dryer

Steam Coils for A Tunnel Dryer

Steam coils consist of a series of pipes or tubes through which steam is passed. The steam, which is at a high temperature and pressure, releases heat as it condenses inside the coils. This heat is then transferred to the surrounding air or the material being dried through the walls of the coils by conduction and convection. As the material moves through the tunnel dryer, it is exposed to the heat from the steam coils, causing the moisture in the material to evaporate and facilitating the drying process.

Types of Steam Coils

Straight - tube coils: These are simple, straight - tube arrangements that are easy to install and maintain. They are suitable for applications where a relatively uniform heat distribution is required. The steam enters at one end of the tubes and exits at the other end after releasing its heat.

Helical - coil steam heaters: Helical - coil steam heaters are made by winding a tube into a helical shape. This design provides a larger surface area for heat transfer compared to straight - tube coils, allowing for more efficient heat exchange. The helical shape also helps to promote better mixing of the air around the coil, resulting in a more uniform temperature distribution.

Finned - tube steam coils: Finned - tube steam coils have fins attached to the outer surface of the tubes. The fins increase the surface area in contact with the air, enhancing the heat transfer rate. This type of coil is commonly used in tunnel dryers where a high heat transfer efficiency is required, as the fins can significantly improve the ability of the coil to transfer heat to the surrounding air.

Advantages of Steam Coils in Tunnel Dryers

Efficient heat transfer: Steam coils can transfer heat efficiently from the steam to the material being dried, ensuring a high drying rate. The high heat - transfer coefficient of steam allows for rapid evaporation of moisture from the material.

Precise temperature control: By regulating the flow of steam through the coils, it is possible to achieve precise control over the temperature inside the tunnel dryer. This is crucial for drying different types of materials, as different materials may require specific drying temperatures to avoid damage or ensure optimal drying quality.

Reliability: Steam coils are relatively simple in design and have few moving parts, which makes them reliable and durable. They can operate continuously for long periods without significant maintenance, reducing downtime and increasing the overall productivity of the tunnel dryer.

Clean and safe: Steam is a clean - energy source, and steam coils do not produce any harmful emissions or contaminants during the drying process. This makes them suitable for drying food, pharmaceuticals, and other sensitive materials where cleanliness and safety are of utmost importance.