Vertical roller mill grinding roller Introduction

A grinding roller is a key component of the vertical roller mill, it is connected to the lower rocker arm along with the hydraulic system. When the vertical roller mill operates, it exerts a force on the grinding table and material is crushed in between. The grinding roller device is mainly composed of the grinding roller shaft, grinding roller body and grinding roller tyre. Tongli, as a professional vertical roller mill spare parts supplier, provides various types of grinding rollers with different specifications and structures. We offer two types of grinding roller, conical type grinding roller and round type grinding roller which is determined on the raw material being ground. Tongli metal casting optimizes the casting process of the grinding roller to improve the metal solidification. Tongli steel casting foundry has a mature casting process and strong machining strength. Tongli steel casting is made of high-quality mild carbon steel and 304 stainless steel that is fresh out from our own fabrication workshop in which the quality of the raw material is strictly controlled.

Strucuture of vertical roller mill

A vertical roller mill (VRM) is a type of industrial equipment used to crush or grind materials into small particles. It's widely used in the cement and mineral processing industries. The structure of a typical VRM includes the following components:

Grinding Disc: This is the main component that rotates and contains the grinding elements. The material to be ground is fed onto the grinding disc, and the grinding elements exert pressure and force to crush and grind the material.

Grinding Rollers: The grinding elements are typically rollers that are mounted on the grinding disc. These rollers can vary in size and shape, but they generally exert pressure on the material as the grinding disc rotates.

Table Liner: The grinding disc is usually lined with a replaceable table liner that helps protect the disc and maintain efficient grinding. The table liner is in direct contact with the material being ground and is subjected to wear.

Grinding Rollers shaft: A forged shaft could refer to various components such as the main shaft that supports the grinding rollers or other critical shafts within the mill's structure. These components need to withstand significant mechanical loads and stresses, and using forged shafts can ensure the necessary strength and durability.

Grinding Rollers wheel hub: The grinding roller wheel hub is a metal casting part that is mounted on the outside of the grinding roller shaft. The wheel hub refers to the central part of the grinding roller that connects it to the driving mechanism of the mill. 

Separator/classifier: A separator is used to separate the ground material from the airflow that carries it through the mill. The finer particles are lifted by the air and transported to the classifier for separation, while the coarser particles drop back onto the grinding disc for further grinding.

Middle shell: The middle casing of the vertical roller mill is a welded structural part, which supports the weight of the entire separator. There are 4 inspection doors on the middle casing for roll overhaul. The door is designed with a sealing sheath that is in close contact with the grinding rollerto Prevent air leakage. The inner wall of the middle shell is laid with a wear-resistant lining to protect the inner shell.

Drive System: A VRM is powered by a motor and a drive system that rotates the grinding disc and the rollers. The drive system can vary based on the size and design of the mill but typically involves gears or belts to transmit the rotational motion.

Base Frame: The support base of the vertical roller mill is generally four peripheral support pedestal and a central support base, and the support base and the installation foundation are connected and fixed by anchor bolts. All the vertical roller mills of Tongli will be pre-assembled and leveling calibrated before leaving the factory to ensure that the equipment can be installed smoothly on site.

Feed and Discharge System: The material to be ground is fed onto the grinding disc through a feed mechanism. Once the material is ground to the desired size, it is discharged from the mill through an outlet.

Pressure System: In Tongli VRMs, a hydraulic or pneumatic system is used to apply pressure to the grinding rollers. This pressure helps control the grinding process and ensures consistent grinding efficiency.

Design principles of vertical roller mill grinding roller

Auto-Molding: Tongli adopts automatic sand release system and sand recovery system, the ratio of resin and sand is fully automated, the molding effect is good, and the strength of the sand mold is high.

Advanced design: Unique design for the sand molding of steel castings. All millstone molds are used on the same day of manufacture to ensure that the sand molds are not damp. After the box is closed, a dehumidifier is used to ensure that the interior of the sand molds is dry.

Process control: Optimized the casting process of steel castings. The riser of the casting is 1.5 times larger than the traditional riser, and the riser is added at the position where the defect of the wire is relatively easy to exit.

Simulation software: Tongli used the simulation software to repeatedly verify the runners of the steel castings, combined with actual casting experience, and finally obtained the optimal casting process.

Composition analysis: Tongli strictly controls the composition of molten steel during the casting process, and uses an imported spectrometer to proof the composition of the casting to ensure that the composition of the casting meets the standard.

Quality assurance: Tongli has strict control over the temperature of molten steel during the pouring process. The desulfurization and deoxidation operations of molten steel promote the floating and removal of non-metallic impurities in molten steel, improve the uniformity of molten steel temperature and composition, and prevent castings from defects such as pores and sand inclusions appear.

Heat-treatingg equipment: Tongli has multiple CNC heat treatment furnaces for normalizing, annealing, quenching, tempering, etc., which fully meet the needs of customers for heat treatment processes.

Surface treating: Tongli is equipped with a shot blasting machine system, and all castings after sand cleaning are shot blasted to ensure the smoothness of the surface of the steel castings.

Machining capability: Tongli has more than 650 sets of machining equipment and rich machining experience, which can meet all the requirements of customers for the machining of steel castings.

Specifications of vertical roller mill grinding roller

Note: *The diameter is middle diameter of the grinding table

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Zhejiang Tongli Heavy Machinery Manufacturing Co., Ltd (Formerly known as Tongxiang Coal&Mining Machinery Factory) established in year 1958 is a member of the Chinese National Building Material Machinery Association. Tongli is on the vendor list of designated production enterprise of the Ministry of Coal Industry. ISO9001、ISO14001、ISO45001 certified, accredited as High-tech & new technology enterprise of Zhejiang Province. With 65+ years of experience, Tongli has earned first class R&D and manufacturing capabilities, dedicated to provide satisfactory manufacturing equipments for global customers.   

Industry Knowledge extension

What is the difference between ball mill and vertical roller mill?

Both ball mills and vertical roller mills plays a vital role in the cement grinding plant. Ball mills are versatile and cost-effective, suitable for various materials and simple to maintain. On the other hand, vertical roller mills offer superior energy efficiency and particle size control, making them ideal for cement and ore grinding applications. The choice between the two depends on specific requirements, budget constraints, and technical expertise.

What is the relationship between vertical roller mill and rotary kiln?

The relationship between a vertical roller mill (VRM) and a rotary kiln lies in their roles within the cement manufacturing process. Both of these equipment are essential components of the cement production line and are used to facilitate the production of clinker, which is the intermediate product in the production of cement.

Vertical Roller Mill (VRM): A VRM is a type of industrial equipment used to crush or grind materials into small particles. It consists of a rotating table onto which materials (such as raw materials for cement production) are fed. The material is then ground between the grinding rollers and the grinding table, creating fine powder. In the context of cement manufacturing, the VRM is used to grind the raw materials (such as limestone, clay, shale, etc.) into a fine powder called raw meal. This raw meal is then fed into the rotary kiln for further processing.

Rotary Kiln: A rotary kiln is a large, cylindrical furnace that is inclined slightly from the horizontal and rotates on its axis. It is used to process raw materials at high temperatures to produce clinker, which is a fused, small, spherical nodules of intermediate product in cement production. The raw meal from the VRM, along with other additives like gypsum, is fed into the rotary kiln. Inside the kiln, the materials undergo a series of complex chemical and physical reactions, resulting in the formation of clinker. The clinker is then cooled and ground to produce cement.