The design of Mineral sizer
Introduce
Crushers often operate under heavy loads and in dusty environments. With the continuous deepening of people’s understanding of the crushing process, new crushing methods and mineral sizers are constantly emerging, and the reliability of products is continuously improving. Effective progress has been made in aspects such as wear resistance of products, reduction of overcrushing volume, and strict control of the particle size of crushed products.
Especially, mineral sizer, with its compact structure, easy maintenance, low energy consumption, low cost, high crushing capacity and durability, has become the first choice for crushing equipment, whether in terms of product structure, technical performance or industrial application.
Classification of crushers
Common types of crushers mainly include jaw crushers, gyratory crushers, cone crushers, hammer crushers, impact crushers and toothed roller crushers, etc.
Toothed roller crusher
The toothed roller crusher is a traditional crushing machine. Its main crushing function is to split and crush. Compared with other types of crushers, the characteristics of this crusher are
(1) The energy consumption during the crushing process is low:
(2) The degree of overgrinding (powdering) is small, and the crushed products are mostly cubic.
(3) Simple structure, reliable operation, and convenient maintenance and repair; Low cost.
Based on the above advantages, the toothed roller crusher is widely used in many industrial sectors.
Mineral sizer
Mineral sizer is a new type of crushing equipment, which is composed of a pair of toothed rollers, two pairs of crushing toothed rollers, synchronous gears, a hydraulic coupling, a frame and an electric motor, etc. The frame is a structural component welded from section steel, and the fixed tooth roller shaft is installed on the fixed bearing of the frame.
The movable gear plate is installed on the shaft hub through bolts, and the shaft hub is then fitted onto the gear roller shaft. The motor rotates the fixed gear roller shaft through the hydraulic coupling, reduction box and coupling. The gear roller shaft drives the shaft and the movable gear plate, causing the movable gear plate to rotate in pairs.
The design of Mineral sizer toothed roller
There are usually two types of the structure of the toothed roller: one is to fit a toothed ring made of high manganese steel onto a cast iron core and fasten both ends with bolts; the other is a bow-shaped toothed plate made of high manganese steel, which is assembled on a cast iron shaft hub with a polygonal cross-section. The structure of the toothed roller is reliable, but it is not convenient for maintenance.
When replacing the toothed ring, the roller must be lifted to disassemble each toothed ring separately. The second type of toothed roller is convenient to manufacture and assemble, and is easy to replace after wear. If the hub is made as a whole, the area at the junction of the toothed plate and the polygonal surface is larger, and the connection is more secure. The types of mineral sizer roller teeth include: eagle-beak type, grab type, blade type and rectangular belt type.
Mineral sizer side teeth plate
Comb plates are respectively installed on the two side walls, which have two functions: to make the crushing process completely shearing and stretching crushing, and to prevent the generation of over-crushed materials. It functions as a bar screen and can pass through materials that do not need to be crushed.
For large pieces of materials that need to be crushed, it can strictly control the particle size of the crushed product, ensuring that the three-dimensional dimensions of the crushed materials can all be controlled. The rotation of the two toothed rollers towards their respective side walls can also ensure that the materials that have already reached the required particle size in the feed are not re-crushed.
They can be directly discharged from the discharge ports between the toothed rollers and between the toothed rollers and the comb plate, thereby reducing the energy consumption of the mineral sizer and the over-crushing caused by extrusion crushing. The two crushing rollers are equipped with two sets of independent drive devices, enabling each of them to operate independently.
Structural design features of Mineral sizer
Due to its outstanding advantages such as compact structure, reasonable material crushing mechanism and strong adaptability, Mineral sizer has great development prospects in the coarse crushing application of open-pit mine materials and is a relatively ideal rock crusher for open-pit mines. Its main features are as follows:
- It adopts a long-toothed, small-roller diameter, helical tooth distribution, and multi-disc four-toothed structure. Through the combined action of shearing, bending, and extrusion, it crushes materials. The crushing mechanism is more reasonable than that of traditional crushing equipment. The crushing teeth are evenly stressed, allowing for a large feeding force, and is particularly suitable for coarse crushing.
- The Mineral sizer has a compact structure, flexible layout, and occupies a small space. Especially with a small crushing height, it can effectively reduce the overall layout height and significantly lower the cost of the crushing station.
- The crushing roller has a low rotational speed, low wear, low noise and little dust.
- The basic design of Mineral sizer is simple. Due to its integral structure, the drive reducer is directly connected to the frame of the crusher, which greatly reduces the force transmitted to the foundation, causes less equipment vibration, and is conducive to installation and movement
- It adopts a specially designed reducer with strong overload capacity, which has strong adaptability to materials. Compared with ordinary roller and feeding crushers, the hardness of the crushed materials is greater. Meanwhile, due to the cross-arrangement of long teeth, they achieve mutual combing effect. The side wall has edge tooth plates, which can also crush sticky materials.
The relationship between crushing teeth and product particle size
Broken tooth profile
The external dimensions of the teeth, including the tooth width and tooth height, shall not exceed the required particle size of the product and should be equal to or slightly less than the required particle size.
The width of the tooth root is approximately 4/5 to 1 times the height of the tooth. The thickness of the teeth (i.e., the size of the teeth along the circumferential direction) is determined by the strength of the crushed material and is generally greater than or slightly greater than the height of the teeth.
Under the premise of ensuring the strength of the teeth, the size should be reduced as much as possible. If the tooth profile is too large, it will cause the product particle size to exceed the limit, losing the classification function. At the same time, it will also affect the passing capacity of small-sized materials entering the mineral sizer.
Moreover, if the tooth profile is too small, not only will the strength of the teeth be reduced, but also the over-crushing phenomenon will be intensified, and it is not conducive to the material being gnaw in.
Material characteristics
The hardness and toughness of the crushed materials also directly affect the particle size of the product. For materials with high toughness, the size of the crushing teeth and the size of the crushing space should be reduced accordingly.
When crushing coke, due to its high toughness, the crushing space of mineral sizer should be basically equal to or slightly larger than the required particle size for crushing. For coal, because of its low toughness and high brittleness, the crushing space should be slightly larger. At the same time, the toughness and brittleness of different coals also vary greatly, so it should be determined according to different situations.
For materials with higher hardness, in addition to reducing the corresponding crushing space, the width of the tooth root should be relatively increased to enhance the strength of the crushing teeth.
The arrangement of the crushing teeth
The crushing teeth of mineral sizer are arranged in a spiral manner along the axis direction, and the adjacent gear discs are staggered at a certain Angle along the circumferential direction. This arrangement is first conducive to the continuous feeding of materials.
The entire crushing process is a linear one, making it less likely for materials to get stuck. Especially when the crushing teeth are large, if a spiral arrangement is not adopted and materials are not evenly fed in, it is very likely to cause jamming.
Secondly, the mineral sizer has a uniform load and is subject to less shock, which is conducive to reducing the power consumption of crushing, saving energy and extending the service life of the mineral sizer.
Thirdly, when large pieces of material are gnawed in, if the roller teeth cannot gnaw them in at one time, they will forcibly slide over their surface. The helical arrangement of the roller teeth will force the material to flip over, waiting for the next pair of teeth to act on it again.
Selection of the drive unit
Electric motor
Mineral sizer uses two independent motors to drive two crushing toothed rollers respectively, forming an independent drive system. The motor is connected to the reducer through a hydraulic coupling, and then the reducer is connected to the crushing gear roller assembly through a self-aligning drum gear coupling to ensure the stable transmission of power to the gear rollers and achieve the crushing operation.
Hydraulic coupling
The hydraulic coupling is a transmission component in the Mineral sizer drive system. It transmits power by utilizing the kinetic and potential energy of the liquid. Its specific functions are as follows:
Stepless speed regulation
Under the condition of constant motor speed, the speed of the Mineral sizer working machine can be adjusted steplessly. Compared with the traditional throttling regulation method, it can significantly save electricity and meet the crushing requirements of different materials.
Optimize startup performance
It supports the light-load or no-load starting of the motor and can gradually start large-inertia loads. Mineral sizer’s toothed rollers and materials to be crushed significantly enhance the starting capacity of asynchronous motors and reduce mechanical shock during starting.
Overload protection
There is no mechanical rigid connection between the pump wheel and the turbine of the coupling. They are flexibly driven by liquid and there is a certain slip. When the resistance moment of the material processed by Mineral sizer suddenly increases, such as when it is blocked by hard rock, the slip can increase or even be temporarily braked, but the motor can still keep running without stopping, effectively protecting the mineral sizer from damage.
Reducer
Mineral sizer’s reducers are equipped with industrial heavy-duty gearboxes from SEW or Flender manufacturers. These gearboxes are highly versatile, reliable in quality, capable of withstanding large load impacts during the crushing process, and have extremely low maintenance costs, ensuring the long-term stable operation of the mineral sizer.
Coupling
Mineral sizer uses self-aligning drum gear couplings. The self-aligning drum gear coupling has a self-aligning function and can effectively compensate for the insufficient concentricity and errors caused by the installation or operation of the gear roller. The tooth profile adopts a flanged design, and the surface is treated with high-frequency quenching, which has an extremely strong torque transmission and impact resistance capacity, and is suitable for the high-intensity requirements of crushing operations. The outer gear sleeve of the double-sided half coupling is designed with a shear pin group. When the Mineral sizer gets stuck due to material blockage or other situations, the shear pin will break first, cutting off the power transmission and thus protecting the drive unit (motor, reducer, etc.) from overload damage.
Summary
As an ideal open-pit rock crusher, Mineral sizer is suitable for coarse and medium crushing operations of materials such as coal and ores, especially in scenarios where it is necessary to control product particle size, reduce overcrushing and adapt to complex material properties. Its design comprehensively takes into account crushing efficiency, energy consumption, maintenance convenience and material adaptability. It is an upgraded and optimized version of the traditional toothed roller crusher and has broad application prospects in the field of industrial crushing.
