• Categories:News Center
• Time of issue:2022-05-06 10:17

(Summary description)In the process of pneumatic conveying, some materials will adhere to the inside of the pipeline, which will reduce the flow area of ​​the pipeline and may even block the pipeline. The reasons for the adhesion of materials in the tube can be roughly divided into the following six categories: (1) Materials with low melting point or low softening point, such as paraffin, thermoplastic resin, sulfur, etc., will melt, soften and bond after being heated and pressed during transportation. (2) Oil-containing plant seeds or other oil-containing materials, during the transportation process, the oil secretions produced after being heated and pressurized will cause adhesion to the pipeline. (3) Superfine materials, especially fine powders with particles less than 1um, such as lead, carbon black, titanium oxide, etc., are easy to adhere to the pipe wall. (4) Materials with hygroscopic or water-soluble properties, such as salts, adhere to the pipe wall by surface moisture. (5) Charged materials, such as synthetic resin powder, grain flour, etc., have a very large adhesion force due to electrostatic action, and are prone to stick to the wall of the pipeline. (6) Materials that adhere to the pipe wall due to mechanical mutual restraint, such as fibers, etc., their adhesion is related to the surface shape of the particles themselves and the shape of the pipe wall.   According to the reason why the material sticks in the pipe, we can take some measures to prevent the pipe from sticking to the wall: (1) Choose a reasonable air flow rate. Different materials will have different adhesion under different airflow speeds. Therefore, according to the specific material characteristics, choosing a reasonable air flow rate will help reduce the occurrence of material adhesion. (2) Use the inner wall to process smooth delivery pipes. The smooth inner wall of the pipe can effectively reduce the containment and friction between the material and the pipe wall, so that the material is not easy to adhere, or it will be taken away by the airflow soon after it adheres. (3) According to the pneumatic conveying requirements of different materials, specific requirements are put forward for the temperature, humidity, pressure value, static electricity content, etc. of pipeline conveying, so as to reduce the possibility of material sticking to the wall. (4) Different requirements should be put forward for the particle size and particle size distribution, physical and chemical properties of the material. For example, the superfine materials mentioned above may not be suitable for pneumatic conveying. (5) Pneumatic conveying after drying the material. For materials with high moisture content, drying is very important. (6) Use large pipe diameter and short distance transportation. When the pneumatic conveying of materials that are easy to stick to pipes is unavoidable, it is recommended to consider large-diameter conveying pipes, and to choose short-distance conveying as much as possible to reduce the number of bends to reduce the degree of material sticking to the wall.