China rolling mill oil film bearing skills (3)

China Rolling Mill Oil Film Bearing Technology (3) Home > Bearing Knowledge > China Rolling Mill Oil Film Bearing Skills (3) This article discusses the operation mechanism of oil film bearings in rolling mills, focusing on the establishment of a mathematical model based on classical smooth theory, numerical calculation methods, and quasi-analytical approaches. These efforts have deepened theoretical research. According to classical theory, the peak pressure of the oil film can reach 100 MPa or more. At that time, researchers primarily focused on elastic flow, especially the high-elastic flow in reverse contact, and considered sliding bearings as atypical problems. Some even believed that heavy-duty oil film bearings were not within the scope of elastic flow theory. However, further studies revealed a unique "necking" phenomenon in the circumferential distribution of the oil film thickness, which is characteristic of the elastic flow theory. The axial distribution of the film also differs from classical theory, with the pressure peak shifting backward. Eccentricity calculations showed Îµ > 1, proving that the smoothness theory of rolling mill oil film bearings belongs to the elastohydrodynamic problem. As modern continuous rolling mills moved toward higher speeds and heavier loads, thermal elasometry theory was introduced. With the deepening of static and dynamic pressure lubrication theories, China developed its first static-dynamic oil film bearing. In terms of product development, China's oil film bearings originated from Soviet-made bearings in the early 1950s. Initially, they were only suitable for low-speed rolling, and their layout, assembly, and disassembly were inconvenient. Starting in the mid-1960s, China began producing thick plate, extra-thick plate mills, and 1700mm hot and cold tandem mills. Due to the difficulty of manufacturing large-scale rolling bearings, oil film bearings were widely used. The first generation of domestic oil film bearings, such as the Ï†1300mm bearing for the 4200mm thick plate mill, was designed for low speed and heavy load. The second generation, like the Ï†1100mm bearing for the 1700mm hot and cold mill, improved speed and layout. The third generation, including the Ï†500mm static and dynamic oil film bearing for the 650mm plate mill, significantly enhanced performance, with double the load capacity and close to Moguil bearings. It was the third independent static-dynamic oil film bearing globally after the U.S. and the former Soviet Union. Chinaâ€™s independent development capability ranks second only to the U.S. and the former Soviet Union. However, in terms of static pressure film research and method selection, China has surpassed them. For example, while the U.S. uses a central oil chamber and the former Soviet Union uses four chambers, China opted for an axially symmetric dual-chamber design. By 1994, oil film bearings had evolved from single to dual chambers, exemplified by the Ï†1350mm TZ oil film bearing for Jiuquan Iron and Steel Company, featuring symmetrical dual-chamber static-dynamic pressure, hydraulic locking, new reverse sealing, bidirectional thrust, and rapid assembly/disassembly. There are three types of oil film bearings in China: pure static, pure dynamic, and static-dynamic. Pure static bearings are not widely used in rolling mills, while pure dynamic bearings are common in reversing and hot strip mills. Static-dynamic bearings are mainly used in cold tandem mills and intensified rolling reversible mills. Key aspects include: (1) Bearing body design and fabrication, involving oil cavity shape, size, orientation, and primary parameters. (2) Ultra-high-pressure oil supply systems tailored to different rolling conditions. (3) Hydraulic locking and rapid assembly/disassembly technology, developed since the late 1970s. (4) Reverse sealing techniques, refined through mold design, rubber compounding, vulcanization, and testing. From these six areas, it is clear that China can produce dynamic, static-dynamic oil film bearings and their corresponding systems, meeting the needs of modern rolling mills. This demonstrates that China's oil film bearing technology has become a comprehensive system, developed through collaboration and integration of foreign technologies.

Dispenser Mass Flow Meter

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Here are the pictures of Sealand Mass Flow Meter in Dispenser for your reference.

Mass Flow Meter 1