The fan used for tobacco drying typically consists of a motor, a drive shaft, a bearing support base, and a fan blade. The motor’s output shaft is rigidly connected to the upper end of the drive shaft via a coupling. The fan blade is mounted on the lower end of the drive shaft and operates via direct transmission. The motor directly drives the rotation of the drive shaft. As a result, transmission stability is high, and the bearings on the drive shaft are not subject to wear. In addition, diesel engines are provided as an option; these can be used to rotate the fan in the event of a power outage, thereby preventing the inability to dry tobacco leaves normally due to power disruptions.

A tobacco-drying fan typically consists of a motor, a transmission shaft, a bearing support base, and a fan blade. The motor’s output shaft is rigidly connected to the upper end of the transmission shaft via a coupling. The fan blade is mounted on the lower end of the transmission shaft and operates on a direct-drive principle. The motor directly rotates the transmission shaft. As a result, transmission stability is high, and the bearings on the transmission shaft are not subject to wear. In addition, diesel engines are provided as an option; these can be used to drive the fan in the event of a power outage, thereby preventing the inability to properly dry tobacco leaves due to power disruptions.
The circulation fan is typically easy to disassemble and install, convenient for maintenance, highly reliable, and simple to use.
In practical operation, effectively reducing energy consumption in dense drying chambers while simultaneously improving the quality of smoking tobacco and achieving energy savings and cost reduction is closely linked to the proper use of circulating fans for both premium and lower-grade smoking tobacco.
During tobacco drying, when the fan is turned on at high or low speed, it must be flexibly adjusted depending on the temperature, humidity, and changes occurring in the tobacco drying process.
Using the fan's lower gear
1. The yellowing stage of tobacco leaves primarily involves the wilting and yellowing of tobacco leaves before the drying temperature reaches 46 ℃. During this stage, tobacco leaves lose less water and typically turn yellow while retaining a certain level of moisture. To enhance the yellowing process of tobacco leaves, a substantial amount of water is required. The fan mainly circulates air within the drying chamber, reducing the vertical temperature and humidity differences between layers, thereby promoting uniform yellowing of the tobacco leaves and consistent dehydration. At this stage, using a low-speed high-temperature circulation fan helps reduce wind speed, minimize moisture evaporation, and save both electricity and fuel consumption.
2. The color-fixing stage of tobacco leaves, typically occurring between 52°C and 55°C, involves the formation of aromatic compounds and color fixation. As the tobacco leaves dehydrate and dry out, the gap between the leaves gradually widens. Using a low-speed setting during this stage not only reduces energy consumption but also promotes the development of aroma in the dried tobacco leaves and helps minimize the color difference between the front and back sides of the leaves.
3. The drying stage of tobacco leaves typically occurs at temperatures ranging from 56 ℃ up to the drying point temperature of the tobacco veins. Provided that the wet-bulb temperature remains stable below 42 ℃, all the leaves will be completely dried, the flow of hot air in the drying chamber will be easily unobstructed, most of the moisture will be removed from the tobacco leaves, and the leaf pulp will become virtually dry. At this point, the high-speed circulating fan used for tobacco drying can be switched to a lower gear—this will reduce wind speed, minimize the evaporation of aromatic compounds, and help save electricity and fuel. At the same time, it is essential to pay attention to shutting down the equipment once the main moisture content of the tobacco leaves has been eliminated and the temperature has dropped below 60 ℃, in order to prevent overheating of the furnace, which could lead to engine failure.
Using high-speed fan transmission
The high-speed setting is primarily used in the tobacco leaf processing stage, which requires significant moisture loss, leaf drying, and color fixation. First, this mode is designed for tobacco leaves with high moisture content—for example, leaves whose surfaces have excessive water accumulation or those harvested during rainy weather. During drying, briefly activate the high-speed setting to remove some of the moisture from the leaf surfaces, then switch to the low-speed setting once the moisture level has decreased. Second, the high-speed setting should be employed for dryers experiencing large temperature fluctuations, high smoke concentrations, and poor ventilation. Once the temperature difference has narrowed, switch back to the low-speed setting. Third, within the temperature range of 48°C to 55°C during the color-fixing process for dried leaves, the primary function of the fan is to gradually accelerate the leaves' moisture loss and promote their drying. Therefore, at this stage, it is necessary to increase the heating power, set the fan to high speed, enhance moisture removal from the tobacco leaves, and ensure uniform drying.