How Does a Raymond Mill Work？

What's a Raymond Mill?

Raymond mill has very long history and is widely used in powder making industry, first appeared in 1906 in Berlin Curt Von Grueber machinery manufacturing factory, development so far and has a history of more than one hundred years. This grinding mill can be used to grind various materials such as limestone, gypsum,  calcite, dolomite, barite, marble, talc, coal powder, etc.

Recent years, with the development of non-metallic minerals in ultrafine powder industry, the requirement about non-metallic products also gets higher and higher, especially for the fineness of products. In order to meet the requirements of different application areas, the development of "energy saving, high reliability, precision, automation" is an inevitable trend. Now, Raymond mill market for energy saving and environmental protection equipment, with processing capacity, high separation efficiency, low energy consumption, will be more popular, and the market demand will be more urgent.

Raymond Mill Working Principle

The Raymond Mill is mainly composed of a host, an analytical machine, a fan, a finished-product cyclone collector, a fine-powder cyclone collector and air ducts. Of them, the host is made up of a frame, an inlet volute, a shovel blade, grinding rollers, a grinding ring and a shell.

When the Raymond Mill is working, materials to be broken are fed into the machine from the feed hopper on the side of machine shell. Relying on the grinding roller device which hangs under the host’s star rack, materials revolve around the vertical axis on the one hand and rotate on the other hand. Because of the eccentric force brought by revolve and rotation, the grinding roller device swings outwards to press against the grinding ring, so that the shovel blade can send materials into the space between grinding rollers and the grinding ring. Next, during grinding rollers roll and squeeze, materials are broken and ground.

Affected by the eccentric force, grinding rollers would tightly press the grinding ring. So, although grinding rollers and the grinding ring are somewhat abrasive, the yielding and fineness of finished products are kept. Besides, the replacement cycle for grinding rollers and the grinding ring is long, free from the shortage that centrifugal mills needs to replace vulnerable parts frequently. As for airflow separation, the airflow flows and circulates along the route: the fan—the mill shell — the cyclone separator —the fan. Thus, compared to high-speed centrifugal mills, the Raymond Mill is of little dust, clean and pollution-free.

After materials are ground, the fan works and wind enters the host to blow powders. Next, these powders are separated by the analytical machine placed on the top of grinding chamber. For coarse powders, they would fall into the grinding chamber to have another grinding while qualified fine powders enter cyclone collector with airflow and are finally discharged out as finished products. And, after that, the airflow would go into the fan along with the air return duct at the top of cyclone collector. The whole wind path is circulatory and flowing under negative pressure. Redundant airflow in the circulatory wind path is discharged from the exhaust pipe between the fan and the host and then collected by the small cyclone collector to be purified.

Working Characteristics of Raymond Mill

1.Small Occupational Area Saving Costs on Foundation Building

Different from ball mills and other grinding mills, the Raymond Mill adopts a compact vertical structure. And in its grinding system, the host, the powder concentrator and other auxiliary devices are connected closely. So, costs of building the foundation can be saved a lot. From raw materials to finished powders, the milling system is a complete powder preparation system. The investment costs are totally acceptable.

2.High Grinding Efficiency, Excellent Precision of Final Products

The new generation of Raymond Mill has made a lot of improvements in the grinding pressure, making full use of the high pressure of springs and the centrifugal force, so that materials can be fully squeezed and ground. Meanwhile, the improvement of the powder concentrator guarantees the selection accuracy and efficiency of Raymond Mill.

3.Lower Energy Consumption, Higher Economic Profits

Under ideal working conditions, Raymond Mill consumes less energy than other ordinary grinding mills. For example, the MTM Medium-speed Grinding Mill only consumes 1.02kW/h when yielding a ton of materials and 1.48kW/h when feeding a ton of materials. Its electricity consumption is lower than that of ball mill at the same level by over 60%.

4.More Eco-friendly Closed-circuit Circulation System

The Raymond Mill forms a complete closed-circuit circulation system with other auxiliary devices together. The system runs under negative pressure. When there are redundant gas which is formed because of the evaporation of water in materials, they can be discharged after purification, better meeting current environmental needs.

Raymond Mill Development Trend

With the development of powder industry, the market has higher requirement about the application of Raymond mill. As one of the key grinding equipment, in order to meet different requirements of various industries, high reliable performance, energy saving and automatic is the inexorable development trend of Raymond mill.

Energy Saving And Environmental Protection

Recent years, people pay more and more attention to environment protection. The development and research of Raymond mill should also pay more attention to high efficiency and energy saving. Manufacturers should optimize the key sections such as non-pollution, high efficiency, low power consumption and service life etc.

Improve The Automatic Control System

In the future powder industry, Raymond mill should be high reliable, accurate, automatic working condition monitoring and automatic control. Automatic control system can effectively improve the grinding efficiency, accuracy and safety of Raymond mill. Besides, it can greatly save manual power.

Improve The Grinding Fineness

With the increasing of requirement about fineness of powder products, grinding equipment will be scaled and refined, so does Raymond mill. For a long time, even manufacturers kept on optimizing Raymond mill in order to improve its grinding fineness, but they seldom have breakthrough. To improve the grinding fineness of Raymond mill, we need to strengthen the accuracy of analyzer, which is always the technical difficulty to optimize grinding mill. so in the future development trend of Raymond mill, manufacturers should pay more attention to this factor.