When we use the dryer, sometimes we will encounter the problem of uneven drying, so what factors will lead to the poor drying effect? Next, I will list some common causes of uneven drying.
- Equipment type is inappropriate: First of all, we need to consider whether the type of equipment is not suitable. When choosing a dryer, we need to choose according to our actual needs. Taking pepper drying as an example, the mesh belt dryer is more suitable for manufacturers with large products and continuous feeding and discharging. The drying room is more suitable for some small workshops, and the materials are dried in batches in a static state, which can better ensure the quality of drying. When the equipment is not properly selected, the production capacity will not keep up, and it will also lead to uneven drying.
- Dehumidification system failure: Dehumidification is a very important stage in the drying process. In each stage of drying, the humidity is different. If the humidity is not well controlled, or the humidity is not discharged in time, the color of the material will be darkened, which will affect the quality of drying.
- Failure of the hot air circulation: The process of hot air circulation is the process of expelling moisture, so when there is a problem with the hot air circulation system, some corners may not be dried, resulting in uneven drying.
- Unreasonable location of tuyere: Material drying usually adopts the form of convection, and the position of the air outlet should be determined according to the nature of the material. Generally, there are two upper and lower air outlets, the air inlet and the air outlet. If the material itself has high humidity and the drying time is longer, you can The actual situation increases the auxiliary tuyere. At the same time, the air volume and speed should be determined according to the size of the drying room and material properties, and the basis for determination is reasonable testing and practical experience.
- Unreasonable design of circulating air duct: The air duct design also plays a very important role in the drying effect of the material. If the design of the circulating air duct is unreasonable, turbulence will occur, and the material itself has a certain degree of difference, which will easily lead to uneven drying. The wind speed of the entire air duct should be as even as possible to avoid dead ends of air supply. There must be a temperature difference before and after the air flows through the material. This is unavoidable. Therefore, it is necessary to reduce the temperature difference as much as possible. One is to increase the air volume, and the other is to reduce the distance of the air supply direction. The air supply of the fan can be made into a forward and reverse mode. , Forward and reverse cycle switching.
In addition, there are some situations that can cause uneven drying, such as the door seal is not up to standard, which will result in poor drying of materials near the door. If the equipment is running for a long time or the frequency of use is too high, the air duct will be blocked, which will cause the air volume and wind speed to fail to reach the predetermined target, and affect the uniformity of the overall drying of the material. For some materials with high sugar content, the method of segmented drying should be adopted, such as blueberries, grapes, tomatoes, etc. For some materials with high water content, it is necessary to prevent the drying time from being too short, which causes only the surface to be dried, and the phenomenon of moisture resurgence occurs after the drying is completed.