We developed a planetary-type rod mill that can improve the comminution working efficiency, prevent the generation of soil dust, and make it easy to clean the used jars. Clods are broken by this device into fine-grain...We developed a planetary-type rod mill that can improve the comminution working efficiency, prevent the generation of soil dust, and make it easy to clean the used jars. Clods are broken by this device into fine-grained soil particles with sizes of less than 2 mm in diameter within 2 min. One objective of this study is to evaluate the performance of the mill by observing the fragmentation process of the clods. The process is visualized experimentally via a high-speed camera installed on a rotating jar of the device. The breakage of the clods in the rod mill is considered morphologically according to the crushing patterns obtained by previous studies. The rod moves together with the clods in the jar. Therefore, violent collisions are not thought to be a major reason for the breakage of the clods. The surfaces of the clods are first scraped and then appear to become fragile. However, if there are no rods in the jar, the clods never break into small pieces. Therefore, it is likely that collisions with the rod trigger the catastrophic fragmentation of the clods into small pieces. This suggests that the design of the device could be modified to improve its performance in the near future.展开更多
Typically, soil samples must be crushed into particles for laboratory research. Thus, an efficient mechanism to ensure a uniform particle size is essential. We previously developed a rod mill device that performs well...Typically, soil samples must be crushed into particles for laboratory research. Thus, an efficient mechanism to ensure a uniform particle size is essential. We previously developed a rod mill device that performs well, but video analysis indicated that the shear forces applied by the rod were more effective than the compressive forces applied by the mill. The mechanism for this phenomenon is unclear. This study focused on clarifying the relationship between compressive load and abrasion when crushing dried and hardened soil particles. Soil pellets of the same size were prepared, and model experiments were performed, where vertical compression and abrasion were applied to the pellets until they fractured. The results showed that soil pellets were fractured easily when an abrasive load was continuously applied in the circumferential direction. Additionally, the load required to fracture the soil pellets was much lower than the required vertical compressive load. The rod mill device was previously thought to fracture soil aggregates by gradually stripping soil particles away from the surface. However, our experimental results clarified that the fracture process started at the center and subsequently induced the entire pellet’s sudden failure.展开更多
文摘We developed a planetary-type rod mill that can improve the comminution working efficiency, prevent the generation of soil dust, and make it easy to clean the used jars. Clods are broken by this device into fine-grained soil particles with sizes of less than 2 mm in diameter within 2 min. One objective of this study is to evaluate the performance of the mill by observing the fragmentation process of the clods. The process is visualized experimentally via a high-speed camera installed on a rotating jar of the device. The breakage of the clods in the rod mill is considered morphologically according to the crushing patterns obtained by previous studies. The rod moves together with the clods in the jar. Therefore, violent collisions are not thought to be a major reason for the breakage of the clods. The surfaces of the clods are first scraped and then appear to become fragile. However, if there are no rods in the jar, the clods never break into small pieces. Therefore, it is likely that collisions with the rod trigger the catastrophic fragmentation of the clods into small pieces. This suggests that the design of the device could be modified to improve its performance in the near future.
文摘Typically, soil samples must be crushed into particles for laboratory research. Thus, an efficient mechanism to ensure a uniform particle size is essential. We previously developed a rod mill device that performs well, but video analysis indicated that the shear forces applied by the rod were more effective than the compressive forces applied by the mill. The mechanism for this phenomenon is unclear. This study focused on clarifying the relationship between compressive load and abrasion when crushing dried and hardened soil particles. Soil pellets of the same size were prepared, and model experiments were performed, where vertical compression and abrasion were applied to the pellets until they fractured. The results showed that soil pellets were fractured easily when an abrasive load was continuously applied in the circumferential direction. Additionally, the load required to fracture the soil pellets was much lower than the required vertical compressive load. The rod mill device was previously thought to fracture soil aggregates by gradually stripping soil particles away from the surface. However, our experimental results clarified that the fracture process started at the center and subsequently induced the entire pellet’s sudden failure.
