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MTW Series European Technology Trapezium Mill

Introduction

The manufacture of European technology trapezium mill uses pure European techniques. It adopts a number of up-to-date technologies, such as the bevel gear integral transmission, internal thin oil lubrication system, arc air duct, etc, and has reached the international advanced level, owning many independent patent rights. So, this type of grinding mill is the latest one creatively designed by the experts of Liming Heavy Industry Science & Technology Co., Ltd, basing on their long-term development experience and dedicated research through adopting 9518 grinding mill users’ suggestions.

The MTW series European technology trapezium mill is mainly applicable to grinding process of mineral materials in metallurgy, building material, chemical and mine industries, etc. It can process the non-flammable and non-explosive mineral materials of hardness less than 9 on Moh’s scale, and the humidity less than 6%, including quartz, feldspar, calcite, talcum, barites, fluorite, tombarthite, marble, ceramic, bauxite, manganese ore, iron ore, copper ore, phosphate ore, iron oxide red, zircon sand, mineral waste residue, water granulated slag, cement clinker, active carbon, dolomite, granite, granat, iron oxide yellow, chemical fertilizer, compound fertilizer, flyash, soft coal, coking coal, lignitous coal, magnesite, chromium oxide green, gold ore, red mud, clay, kaolin, coke, coal gangue, porcelain clay, kyanite, fluorspar, bentonite, medical stone, rhyolite, diabase, pyrophyllite, shale, red sandstone, stromatolite, basalt, gypsum, graphite, carborundum, thermal insulation material, etc.

Structure Features:

The European technology trapezium mill mainly consists of the host machine, powder classifier, fan, jaw crusher, bucket elevator, magnetic vibrating feeder, storage bin, bag-type dust remover, pipes, cyclone powder collector, electrical cabinet and motor, etc. The complete mill is in vertical structure, occupying a small area and belonging to a complete set of plant. A closed gearbox is used as the transmission device of the host machine, which ensures the stable transmission. The key parts of the mill are all made of high-quality steel. Therefore, the complete machine is wear resistant and reliable. The electricity of the mill adopts a centralized control, the type selection is advanced and reasonable, and has high degree of automation. The vibrating feeder is small in volume and light in weight, easy to operate and maintain. In addition, it is very power-saving.

New Performance Features:

1. Bevel gear integral transmission: The traditional mill needs an additional speed reducer and the main shaft is driven through a coupling. In addition, the alignment is hard to handle during installation, and noise will be generated and the efficiency is low. The MTV series European technology trapezium mill adopts the integral bevel gear integral driving, which makes the structure more compact, installation and adjustment more convenient and quicker , and the efficiency increased greatly.

MTW-European-Trapezium-Mill MTW-European-Trapezium-Mill

2. Internal thin oil lubrication system: The traditional mill is generally lubricated with grease. In that case, the lubrication resistance is large, and the temperature rises high and the service life is short. The MTV series European technology trapezium mill adopts the internal oil pump, it is not necessary to add an additional oil pump or lubrication station to lubricate the bearing of the main shaft and the bevel gear shaft.

3. Arc air duct: The air duct of a traditional mill is of straight panel type. In such structure, resistance force may be generated when the air impacts the air duct panel. And the energy loss is large due to the crashing between airflow molecules, thus the air duct may be subject to jamming because of vortexes. The MTV series European technology trapezium mill adopts the curve-surface air duct, and the inlet for tangential airflow is smooth, so the resistance is very small. The internal outlet direction is good for scattering the material and blocking is avoided.

4. The curve-surface spading tool whose blade can be replaced. The blade of the traditional mill is easily worn. Its spading tool is integral, so the whole tool needs to be replaced when the blade is worn. In that case, the material is wasted and`the shut down time for replacement is long, while the blade of MTV series European technology trapezium mill is made of alloy material with high wear resistance, it has a long service life. You only need to replace the blade part when replacement is required. In addition, if you use the traditional straight surface spading tool, the material will be piled on one layer after it is spaded, this may result in bad wear of the middle part of the mill roller and grinding ring, while the curve-surface spading tool can make the material move to the vertical surface, in this case, the upper, middle and lower parts of the mill roller and grinding ring all can be used for grinding, so the wear is uniform. At the same time, the effective working area is enlarged, thus the output is improved as well.

5. Isolated cyclone power collector: An isolated structure is used between the internal cylinder and the mixed air and powder, so the powder classification efficiency and precision will be greatly improved.

6. Air-inlet volute shell with no resistance (no vortex available at the small observation door): The internal door panel of the observation door of the air-inlet volute shell for the tradition mill is protuberant outward, and it is not on the same plane with the air-inlet volute shell, in this case, eddy-current effect may occur and the energy consumption of the system will be increased. As for the MTV series European technology trapezium mill, the internal door panel and the inner surface of the air-inlet shell is on the same curve surface. Therefore, eddy-current effect can be avoided.

7. Exquisite appearance: The European technology trapezium mill adopts many advanced structures. Besides, its appearance is designed in beautiful arc shape, which makes the whole machine look pretty and smart.

Working Principle

The complete machine of the European technology trapezium mill is vertical in structure, occupying a small area and belonging to a complete set of plant. In addition, the transmission device of the host machine is a closed gearbox which ensures stable transmission. The key parts of the mill are all made of high-quality steel, so the

complete machine is durable and reliable. The electricity of the mill adopts a centralized control, the type selection is advanced and reasonable, and has high degree of automation. The vibrating feeder is small in volume and light in weight, easy to adjust and power-saving. The working process of the complete machine of the European technology trapezium mill is as follows:

Bulk materials will be conveyed into the storage hopper by the elevator after being crushed into granules with the required size by a jaw crusher. Then the granules will be conveyed into the grinding chamber of the main machine uniformly, quantitatively and continuously by the vibrating feeder for grinding. Next, the grinded powder will go up with the airflow of the fan and be classified by the powder selecting machine. The powder with the qualified fineness will enter the large cyclone collector for separate collection after going through the pipeline with the airflow, and at last, it will be discharged from the powder valve as the finished powder. The airflow will be sucked into the centrifugal induced draft fan from the return air pipe on the upper part of the large cyclone collector. The whole airflow system of this machine is a closed circulating one, and circulates under the positive and negative pressure condition.

The working process of the host machine of the MV series European technology trapezium mill is to drive the central shaft rotate through the bevel gear integral transmission system. A mill roller hanging rack is bound on the upper part of the shaft. The roller device is mounted on the rack and forms the supporting point for swinging.

The mill roller device not only rotates around the central shaft, but also revolves around the grinding ring. The mill roller revolves on its own axis due to friction. There is a spading tool under the hanging rack, the location of which is the bottom end of the mill roller. The material is up-thrown and fed into the space between the mill roller and grinding ring in the process of synchronous rotation of the spading tool and the mill roller, and forms a cushion material layer. The material on this layer is grinded and crushed due to the outward centrifugal force (namely extrusion force) generated by the rotation of the mill roller. Thus, the powder-making process is completed.

The powder-classification function of the powder classifier on the MV series European technology trapezium mill is achieved through the adjustable speed motor driving the blade on the rotation plate. The speed of the blade can be adjusted according to the particle size of the finished powder. If to obtain fine powder, it is necessary to improve the rotation speed of the blade so as to increase the frequency that the blade contacts with the powder and to make the unqualified powder thrown towards the external wall by the blade and separated from the air follow. The coarse powder will fall into the grinding chamber for re-grinding due to its own gravity. The qualified finished powder will be sucked into the large cyclone collector together with the airflow through the blade. And the powder will be collected after it is separated from the airflow.

The large cyclone collector plays an important role in the performance of the mill. The airflow with powder is under the high-speed rotation condition when it enters the collector. After the airflow and the powder are separated, the airflow body wall will shrink and move towards the center. When reaching the cone bottom (from the free length of the airflow), it forms a rotating upward airflow cylinder, and the powder will fall off and be collected at this time.

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