Crushing equipment is the general name of crushing machinery and grinding machinery.Both are usually arranged as pergranularityRoughly distinguish the size of: those whose particle size is more than 3 mm account for more than 50% of the total discharge amount are called crushing machines;Grinding machinery refers to those whose content is less than 3mm and accounts for more than 50% of the total discharge.Sometimes grinding machinery is also calledCrushing machineryThis is the narrow meaning of crushing equipment.applicationMechanicsA machine that can crush solid materials into small pieces, fine powder or powder.The characteristics of crushing operation with crushing machinery are large energy consumptionWear-resistant materialandGrinding mediumLarge amount of dust andNoiseBig etc.
Chinese name
Crushing equipment
Foreign name
Crushing equipment
Simple crushing tool
Pestle and mortar
Principle
Lever principle
Properties
General term of crushing machinery and grinding machinery
In China, the simplest crushing tool, pestle and mortar, appeared more than 2000 BC.The pestle and mortar further evolved into the foot pedal in 200-100 BC.These tools use the lever principle, and initially have the rudiments of machinery. However, their crushing action is still intermittent.
Crushing equipment
First to adopt continuous crushing actionCrushing machineryIt is a kind of animal mill invented by the public transportation group in the fourth century BC. Another kind of crushing machine with continuous crushing action is the roller mill, which appeared later than the mill.After 200 AD, Du Yu and others in China developed a series of connected water mills, two connected water mills, and water to water mills based on the pedal mills and animal powered mills, raising production efficiency to a new level.These machines are not only used for grain processing, but also extended to the crushing operation of other materials.
The modern crushing machinery was created one after another after the steam engine, motor and other power machinery were gradually perfected and popularized.In 1806, steam engine drivenRoll crusher；In 1858, American Blake invented theJaw crusher；In 1878, the United States developedGyratory crusherIts production efficiency is higher than that of jaw crusher with intermittent crushing action;In 1895, William of the United States inventedImpact crusher。
At the same time, the grinding machinery has also made corresponding development. In the early 19th centuryBall mill；In 1870, based on the ball mill, a rod mill with uniform discharge particle size was developed;In 1908, an autogenous mill without grinding medium was created.In the 1930s and 1950s, the United States and Germany successively developed vertical shaft mills such as roller bowl mills and roller disk millsMedium speed coal mill。
The appearance of these crushing machines has greatly improved the efficiency of crushing operations.However, due to the different crushing characteristics of various materials and the different grain size requirements of different industries, many kinds of crushing machines, such as wheel mill, vibration millturbo Grinder Air flow mill, fan mill, sand mill, colloid mill, etc.By the early 1970s, large scale products with an output of 5000 tons per hour and a maximum feed diameter of 2000 mm had been producedGyratory crusher, and a colloid mill that can grind materials to a particle size of less than 0.01 μ m.
purpose
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The following main purposes can be achieved by using grinding machinery: ① reduce the particle size of materials to a certain size, such as grinding flour, grinding feed, grinding raw and clinker of pigments, dyes and cement, grinding slurry to prepare suspension, and increasing the fluidity and filling ability of materials and facilitating packaging, storage and transportation; ②After crushing, the materials are sieved into small pieces, fine particles or powders of different particle sizes, such as preparing block stones, crushed stones and artificial sand for concrete and road construction projects, and crushing raw coal into medium pieces, small pieces and pulverized coal according to user needs; ③Increase the surface area of the material to improve the effect of its physical action or the speed of chemical reaction, such as grinding the material to be dried manually to speed up its drying speed, grinding the catalyst and adsorbent to strengthen its catalytic efficiency and adsorption respectively, grinding the coal into pulverized coal to improve its combustion speed and combustion completeness; ④Separate the different components in the material after crushing, so as to further separate them from each other. For example, after crushing the iron ore, obtain refined iron ore powder through magnetic separation or flotation, and after crushing the lead zinc ore, separate lead ore powder and zinc ore powder.
classification method
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There are many ways to classify crushing equipment, either by structure, crushing method, motion speed, force type, or degree of refinement.The classification and main characteristics of crushing machinery are listed in the attached table.The pulverization ratio and the pulverization ratio of the pulverization system refer to the change degree of the particle size of the material before and after pulverization.For a single crushing machine, it is equal to the ratio of the maximum (or average) particle size of feed to the maximum (or average) particle size of discharge;For the crushing system composed of multiple crushing machines, it is equal to the ratio of the initial feeding particle size to the final discharging particle size, or equal to the continuous product of the crushing ratio of each single crushing machine.When crushing machinery is used to crush materials, the crushing ratio is usually called the crushing ratio.When the crushing ratio is very high, the crushing operation is often completed in the crushing system composed of several crushing machines.In this system, the particle size of materials will gradually decrease after passing through various crushing machines, and finally reach the required particle size.In this kind of crushing system, appropriate crushing machinery and crushing ratio should be selected at each stage to maintain the production capacity of mutual cooperation between each stage.At the same time, in order to reduce excessive crushing to improve crushing efficiency and reduce energy consumption, screening or grading must be carried out after each crushing operation.According to the degree of subdivision, the crushing equipment can be divided into rubber and plastic crushing equipment, turbine crushing equipment, airflow crushing equipment, vertical crushing equipment without screen, ultrafine classifier crushing equipment and other special supporting machinery, crushing equipment, etc.
Classification Introduction
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Crushing equipment is generally divided intomachine mill （machinemill）、Airflow mill（pneumaticcracker）、Grinder(grindingmachine) andlow-temperature mill (low temperaturemill) four categories:
machine mill
1. Mechanical crusher is a kind of machine mainly used to crush materials in a mechanical way. It is also divided intotooth mill 、Hammer mill、knife mill 、Turbine mill、Press millandmilling breaker Six categories:
（1）tooth mill (toothmill): a machine that pulverizes materials (including impact, shearing, collision, friction, etc.) by the high-speed relative operation of fixed gear ring and rotating gear disk.
（2）Hammer mill(hammermill): a machine that pulverizes materials (including hammering, collision, friction, etc.) by the relative movement of high-speed rotating movable hammering parts and fixed rings.Hammer crusher is divided into movable hammering parts and sheet partspaddle mill (paddlemill) and block mill with movable hammering parts as blocks.
（3）knife mill (knifermill): a machine that pulverizes materials (including shearing, collision, friction, etc.) by the relative movement of high-speed rotating knife plates (blocks, pieces) and fixed gear rings.Knife crusher is divided into:
a. Multi stage knife mill: a machine with horizontal spindle, parallel blade and spindle, and single or multi-stage crushing function.
b. Multi stage inclined knifermill: a machine with horizontal spindle, inclined knife type and single-stage or multi-stage crushing function.
c. Combined vertical knife mill: horizontal spindle and multi-layer vertical knife combination crusher.
d. Vertical type knife mill: It is a crushing machine with vertical spindle, side knife rotary table movement and grading function.
（4）Turbine mill(turbo mill): a machine that pulverizes materials (including shearing, collision, friction, etc.) by the relative movement of high-speed rotating turbine blades and fixed gear rings.
(5) Press grinder: a machine that grinds materials by relative motion of various grinding wheels and fixed grinding surfaces.
(6) Milling grinder: a machine that grinds materials by milling teeth.
Airflow mill
2、Airflow millIt is a machine that converts compressed air (or other media) into airflow beam through the nozzle in the crushing chamber to speed energy, and causes strong impact and friction between materials to achieve crushing.
Grinder
3. Grinding machine is a machine that grinds materials into superfine mixture through the movement of grinding body, head, ball and other media.It is divided into:
(1) Ball mill: a machine with porcelain ball or stainless steel ball as grinding medium.
（2）Mortar grinder(mortarmill): a machine that grinds materials by the relative movement of the vertical grinding head to the milk bowl.
（3）Colloid mill(colloidmill): a machine that grinds liquid-solid materials by the relative movement of paired grinding bodies (surfaces).
low-temperature mill
4. Low temperature grinder is a machine that is processed at low temperature (minimum temperature - 70 ℃) to crush materials.
Comminution theory
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Theoretical Hypothesis I
The crushed material is subject to its own gravity or external force, enters the crusher from the feed port, and then rotates at high speedCentrifugal discThe centrifugal force is distributed along the radial direction, and then flies toRing gear plateIn this way, materials and ring gear plate, materials and materials constantly collide and friction with each other, and materials are constantly crushed until they reach a certain finenessScreen plateIt is out of the pulverizer and becomes the required product.
Theoretical Hypothesis II
Crushing methods There are five main methods for mechanical crushing of solid materials, namely extrusion, bending, splitting, grinding and impactstatic forceThe last one uses kinetic energy.In most crushing machinery, materials are often crushed under the combined effect of more than two crushing methods, such as crushing machineryGyratory crusherMedium, mainly used for extrusion, splitting and bending;In ball mill, impact and grinding are mainly applied.The crushing method is selected according to the physical characteristics of the material, the size of the material block and the required degree of refinement.For hard materials, extrusion, bending and splitting shall be adopted;For brittle materials, impact and splitting shall be adopted;When the material block is large, splitting and bending shall be adopted;If the material block is small or the discharge granularity is required to be small, impact and grinding shall be adopted.If the crushing method is not properly selected, it will be difficult to crush or over crush, both of which will increase the energy consumption in the crushing process.
Theoretical Hypothesis III
Energy consumption and a lot of crushing work in crushing theory industry and agricultural production consume a lot of energy, but in crushing work, most of the energy input into the crushing machinery is converted into heat and absorbed by the crushing machinery, circulating air and crushed materials, but the amount directly used for material crushing is very small: in crushing machinery, it generally does not exceed 10%;In grinding machinery, it is often less than 1%.Therefore, in order to reduce energy consumption, it is necessary to select appropriate crushing machinery, adopt correct operation methods, and specify the best crushing ratio and output per unit time.Under normal working conditions, the energy consumption levels of different refining ranges are roughly as follows: ① crushing to 100 mm 3~4 kilowatt hours/ton; ②Crushed into 100~10mm 5~6kWh/ton; ③Crushed into 10~0.125mm 20~30kWh/ton; ④Crush to 0.125mm, 100~1000 kWh/ton.Taking an ordinary cement plant as an example, the power consumption of crushing machinery accounts for about 10% of the total power consumption of the plant, while the power consumption of grinding machinery accounts for about 60%.Therefore, measures to reduce excessive crushing must be taken in the crushing process to achieve the purpose of energy saving.
The comminution theory mainly studies the relationship between the energy consumption and the degree of refinement in the comminution process.Since crushing operation is an extremely complex process involving many factors, there is no universally accepted unified conclusion on crushing theory, but only three important hypotheses.They are: Li in GermanyCameron Tringale Proposed in 1867Area hypothesisWhen solid materials are crushed, the energy consumption is proportional to the newly generated surface area;Kiek of Germany proposed in 1885Volume hypothesisIt is considered that the energy consumption is proportional to the volume or weight of the crushed block when the same kind of materials with similar geometry are broken into products with similar geometry;Bond of the United States and Wang Rendong of China proposed in 1952Fracture hypothesis。
These three hypotheses have their limitations in practice. The area hypothesis is more suitable for grinding operations with discharge granularity of 0.01~1mm, the volume hypothesis is more suitable for coarse crushing and intermediate crushing operations with discharge granularity of more than 10mm, and the crack hypothesis is between the two, which is suitable for a wide range of operations from intermediate crushing to coarse grinding.
Production application
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Crushing equipment
With the progress of history and production, shredders are widely used in production, scientific research, medical and other industries.In pharmaceutical production, pharmaceutical raw materials need to be crushed to a certain degree of fineness before they can be granulated, and then pressed into tablets or granules. Some even need to be ground into micro powder to make ophthalmic drugs. Especially in the production of traditional Chinese medicine, some raw materials are fiber, solid, or cream. Therefore,Various types of shredders are needed to process these APIs;In the chemical industry, in addition to liquid and gas products, other products also need to be crushed;Food factories can't produce chocolate and all kinds of sweets without shredders;In the feed industry, the grinder is the most important production equipment. Whether the grinder is selected properly or not directly affects the feed output and the economic benefits of enterprises. In addition to the above industries, there are also mineral, coating, metallurgy and other industries, and even scientific research institutions are in great need of the grinder.Therefore, how to design an advanced grinder that is more suitable for the production needs of all walks of life is the top priority of the grinder production units.
Installation and commissioning
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1. Preparation before installation of crushing equipment
1-1 Carry out necessary process and civil design according to the applicable occasions, the outline dimension drawing of the machine and the foundation location drawing.The dynamic load factor is recommended to be 3-4.
1-2 Sufficient maintenance and feeding space shall be reserved around and above the crushing equipment (see the general drawing description of equipment of various specifications for details).
1-3 The motor foundation shall be poured simultaneously with the machine foundation.
1-4 Prepare necessary tools and lifting facilities.
1-5 Organize relevant personnel to carefully study the installation specifications.
2. Crushing equipment installation
2-1 The machine rotor has been calibrated for dynamic and static balance before leaving the factory, and the user usually does not need to do balance test again when installing.If the hammer head or rotor parts need to be replaced, the radial symmetry deviation shall be less than 0.5kg
2-2 The foundation shall have sufficient strength before the installation of the host and motor.
2-3 The machine (lower body and rotor) shall be installed horizontally, the horizontal error of the main shaft shall be less than 0.35mm/m, and the axial centers of the driving and driven pulleys shall be in the same plane.
2-4 Adjust the tightness of the V-belt properly.
2-5 Check whether all parts of the crusher are displaced or deformed;Lock all bolts;Check whether the seal is in good condition.
2-6 Check the wiring and fastening of the electric control cabinet;inspectTime delay relayandOverload protector；Select the fuse with proper specification;Connect the circuit before the upper V-belt, and the test motor turns (the machine is forbidden to reverse!)
2-7 Check whether the grate positioning and limit are correct, and whether the iron discharging mechanism is flexible). When the machine is initially installed and used, the grate shaft should be at the lowest limit position for adjustment.)
2-8 Manually turn the rotor to check whether there is friction and collision.
Operation precautions
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Test run transfer:
1. Close the magnetic starter handle to power on;
2. Press the button manually for two or three times;
3. Start and idle for 1~2 weeks;
4. Combined operation of loader and crusher;
5. Check whether there is any abnormality and send the start signal.
6. During operation, the machinery and motor shall be free from vibration, the sound and humidity shall be normal, the temperature of each bearing shall not exceed 75 ℃, and the motor temperature shall not exceed the manufacturer's regulations;
7. The chain tightness of the loader must be consistent. Under full load, the chain tightness is not allowed to exceed the length of two chain links, and there shall be no chain jam or chain jump;
8. Wood or other materials shall not be used to replace the fusible plug or explosive piece of the transfer machine joint when damaged;
9. The safety device of the protective net of the crusher shall be kept in good condition, and it shall be checked frequently during operation. If it is damaged, it shall be stopped immediately for treatment;
10. The tail protection and other safety devices of the loader must be intact;
11. Transfer machine.
(1) Clean the floating coal and gangue at the tail, both sides of the fuselage and under the bridge;
(2) Protect cables, water pipes and oil pipes and hang them neatly;
(3) Check the roadway support and move the loader under the condition of ensuring safety;
(4) , trolley andBelt conveyorThe tail frame shall be in good contact without deviation, and shall be well lapped after removal to prevent large pieces of coal gangue from damaging the belt and ensure smooth coal flow;
(5) After the transfer machine is moved, the head and tail of the machine shall be kept flat, straight and stable, and the jack rod shall be retracted.
Introduction to straw crushing equipment
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According to the difference between crushing methods and crushing means, straw crushing equipment in China mainly includes: chopper cutting crushing, hammer plate crushing, kneading cutting crushing, combined crushing, etc.
Guillotine pulverization
GuillotineStraw grinderIt has the functions of cutting straw, crushing grain and rubbing straw.The main equipment of chopper type pulverization is grass chopper (Figure 1), which can be divided into small, medium and large types according to model size;It can be divided into roller type and disc type according to the cutting mode;According to the operation mode, it can be divided into field direct harvester and fixed grass chopper.Among them, medium and large grass choppers are generally disc type, and small grass choppers are mostly drum type.
Hammer crushing
paddle mill It is the most widely used crusher, which uses high-speed rotating hammers to crush materials.According to the different feeding directions, it can be divided into three types: tangential feeding type, axial feeding type and radial feeding type.
Combined comminution
Combined comminution technology is a new type of comminution technology that combines the functions of cutting, collision, comminution, grinding and rubbing.Bao Zhenbo of Tianjin Agricultural University and others conducted optimization design research on the parameters such as the clearance between moving blade and fixed blade, the clearance between hammer blade and toothed plate, the clearance between hammer blade and screen mesh, the number and arrangement of moving blades, the shape and arrangement of hammer blade, and the shape and arrangement of serrated blade in the combined straw biomass grinder.fromNanjing Institute of Agricultural Mechanization, Ministry of AgricultureThe JF-720 multi-function straw grinder researched and designed by Xiao Hongru et al. has two processing rooms, namely, kneading and crushing, which integrates the functions of kneading and crushing, with good crushing effect and stable technical performance;The multifunctional straw grinder developed by Ren Shihu, et al. of Heilongjiang Academy of Agricultural Reclamation Sciences, is manufactured with new technology and new process, with simple structure, convenient operation, high efficiency and moderate price.[1]
Superfine jet mill
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Impact jet mill
This kind of airflow crushing equipment is also often called counter jet typeAirflow mill。In fact, two high-speed air streams are used to wrap the particles to be crushed and collide with each other to achieve the crushing effect, which has a high energy utilization rate, can effectively prevent the high-speed impact of the airflow grinder from causing damage to components, and can facilitate the solution of the problem of particle pollution.Its principle in the working process is that the two streams of pressure and speed are completely consistent, and the two streams of pressure and speed are completely consistent, and the two ends directly enter the crushing area in a straight line, and the materials will be sent to the crushing area through the screw feeder. After complete mixing, the particles will collide with each other and thus achieve the crushing effect,After crushing, the particles will gradually move to the low-pressure area with the flow of gas, the fine powder will be discharged from the upper part, and the coarse powder will return to the crushing area to continue crushing.
Flat jet mill
The working principle of this type of airflow crushing equipment is: compress the air, use the high-speed jet negative pressure difference of the feeding ejector to promote the materials to be sucked into the mixing chamber, use a specific angle with the radius direction of the crushing chamber, and at the same time enable them to be distributed on the same level of nozzles, and spray the high-speed jet into the crushing chamber,The jet stream carries the materials together at a very high speed, which creates a gradient with hydrodynamic characteristics above the radius of the crushing chamber. The material particles collide violently, and will also interact with the pile foundation of the crushing chamber wall. The crushed particles will move at a high speed along with the rotating flow and generate huge centrifugal force,At the same time, it will also be affected by the centripetal force from the air flow to the center of the grinding chamber. These two forces interact, and the particles will also be classified.
Compared with other airflow crushing equipment, the advantages of this equipment include simple structure, simple operation, and automatic classification function.Disadvantages: If the hardness of the crushed material is large, the material will rub violently with the inner wall of the grinding chamber due to the high-speed air flow, which will cause damage to the grinding chamber, and will also cause a certain degree of pollution to the product.
Fluidized bed jet mill
The working principle of this kind of crushing equipment is: adding materials to the crushing equipment, using two-dimensional setting of multiple nozzles to spray the impact energy, and the suspension, tumbling, collision and friction generated after the expansion of the air flow to achieve the crushing effect, and grading by the grading device set at the top under the influence of negative pressure air flow at the upper air flow near the intersection point,The fine powder will be discharged, and the coarse powder will return to the crushing area under the influence of gravity for further crushing.Compared with the impact airflow crushing equipment, it has more excellent dispersion performance. At the same time, the strength of the product can be adjusted by the classification equipment. The wear of the equipment components is relatively small, and the energy consumption is low. It can be applied to large-scale industrial production.
Impact ring airflow mill
Replacing fixed impact parts with rotatable impact rings can avoid the previous two typesAirflow millThe local wear caused by the medium and high speed airflow or gas-solid flow under the impact of a fixed position for a long time makes each position of the overall torus act as the impacted surface in turn, and the overall torus will be subject to relatively close impact wear, which can also promote the life of the impact ring to be extended as far as possible.
The main advantage of this equipment is that the direction of motion of the impact cyclotron is opposite to the jet air flow, so the relative speed can be increased, which helps to enhance the crushing effect.[2]
