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History of Raymond Roller Mill

Source: Grinding Mill   Posted: 2020-09-27   

Who invented Raymond mill?


In 1906, CVGrueber founded the Curt Von Grueber machinery factory in the southern suburbs of Berlin. Using his patents in the United States, he produced the first Maxecon mill and used it as a coal-fired equipment for the MOABIT power station in BEWAG in Berlin. The grinding capacity can reach 5 T/H, sold nearly 600 units in a few years, respectively, used in the field of grinding in different industries. After E.C. Loesche became a shareholder and headed the Curt Von Grueber machinery factory, he decided to purchase the US patented raymond centrifugal ring roller mill to produce the first Raymond mill system.



However, since the grinding power (centrifugal force) of the Raymond grinding wheel was limited by the diameter and speed of the grinding roller, the grinding mill/Raymond roller mill was only applicable to soft, low ash and easy-grinding coal materials at that time. The German coal is harder, the ash is higher, and the higher the grinding power is required. The Raymond roller mill of this structure is difficult to meet the grinding requirements, so the Raymond mill is not popular in Germany. At that time, Raymond mill was suitable for the grinding requirements of American coal, so Raymond roller mill was widely promoted and applied in the United States.



Who improved Raymond mill?


In 1925, ECLoesche summarized the use characteristics and structural drawbacks of the first generation Raymond mill, decided to further improve the grinding structure of the Raymond mill, and developed a grinding machine with the opposite principle of grinding, called improved type Raymond mill. The ventilation of this improved Raymond mill system has two modes: positive pressure and negative pressure. This type of Raymond mill patent was soon purchased by Combustion Engineering. Since the modified Raymond mill still has the problem of ring roller grinding, although the roller diameter is slightly increased, the grinding strength is not increased much.


Later, the Raymond branch of the American Combustion Engineering Company developed a new generation of Raymond mills based on this, called VR grinding. This Raymond mill is similar in many respects to the structure of the current Loesche mill. It is worth noting that it differs from the Loesche mill conical roller and the plat grinding disc, but uses a cylindrical grinding roller and a grinding disc with a 15 degree angled inclined grinding surface. The grinding rolls have a roll-out device similar to the Loesche mill during inspection and repair, and are also equipped with protective devices to prevent metal contact between the grinding rolls and the grinding disc. In addition, the grinding roller can be lifted in advance before the mill is started, which can reduce the starting torque of the motor. Raymond mill is commonly used in industrial applications in the United States to prepare pulverized coal. The fineness of the product varies between 250 and 325 mesh, and the product fineness and yield can be adjusted during operation.


Since May 31, 1995, Raymond mill as the first product ,who applied its patent under its own product name. It has been nearly fifteen years old. With years of development and improvement, the types and models of Raymond mill are becoming more and more, due to the stable performance, strong adaptability and high cost performance of Raymond mill, China's introduction has been well received by users for many years, occupying a very important position in the crushing equipment.