Distributor / authorized representative that deals with supply & delivery of crushers (mills) to industrial enterprises of Russia
Engineering company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), Russia, has been successfully working with a number of Russian industrial enterprises at the local market for more than 20 years. Since the company’s founding, it has acquired immense engineering experience, market reputation, and has realized more than a hundred large-scale projects at the industrial plants in Russia. Our company is continuously in search of new business partners, who consider Russian market investment-attractive and want to boost their sales in the region, as well as expand their field of activities and enter a new international level.Contents:
We are interested in cooperation with the manufacturers of crushers (mills), who are looking for an official and reliable distributor to deal with supply & delivery of their equipment to the industrial plants in Russia.
The company’s top management and sales team are well acquainted with the Russian market, its mentality and laws; they also understand industrial specifics of the financial and economic activities of the Russian customers. All our sales managers have a large customer database, extensive experience of successful sales and well-established connections with the potential buyers of your crushers (mills). This allows our managers to promptly set out the most promising directions for promotion and to ensure a rapid entry of the products into the promising Russian market. Our employees, who are fluent in English and German, are focused on working at the international market with the supplies of foreign equipment.
Our team of experienced engineers, who can handle the most serious technical problems, constantly keeps in touch with the Russian customers, holds meetings and delivers presentations regarding the latest achievements of our manufacturing partners. They point out the engineering challenges and actively communicate with all the departments at Russian plants. That is why the specifics of doing a business in the Russian Federation are well-known to us, and we also know the equipment of the local industrial plants and their up-to-date modernization needs.
Once we become your authorized representative in Russia, our marketing staff will carry out a market research in order to check the demand for crushers (mills), will submit a market overview for crushers (mills) that you offer and evaluate the needs for this type of equipment at local plants. Our specialists will also estimate the potential and capacity of this market at local industrial plants. Our IT-team will start developing a website for your products in Russian. Our experts will assess the conformity between your crushers (mills) and customer needs as well as analyze the common reaction to the new goods in general. We will look into the categories of potential customers, and pick out the largest and the most promising plants.
Upon becoming your authorized agent on the territory of Russia, ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will obtain certificates, if required, for a batch of the goods, for various types of crushers (mills) in compliance with Russian standards. We can also arrange the inspection in order to obtain TR TS 010 and TR TS 012 Certificates. These certificates provides permission to operate your equipment at all industrial plants of the EAEU countries (Russia, Kazakhstan, Belarus, Armenia, Kyrgyzstan), including the hazardous industrial facilities. Our company is eager to assist in issuing Technical Passports for crushers (mills) as per Russian and other EAEU countries’ requirements.
Our engineering company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), collaborates with several Russian design institutes in various industrial segments, which allows us to conduct preliminary design as well as subsequent design works according to the standards, construction rules and regulations that are applicable in Russia and other CIS countries. It also enables us to include your crushers (mills) into the future projects.
The Company has its own logistics department that can provide packing service, handling as well as the most efficient and cost effective mode of transportation of the goods (incl. over dimensional and overweight goods). The goods can be delivered on DAP or DDP-customer’s warehouse basis in full compliance with all the relevant regulations and requirements that are applicable on the Russian market.
Our company has its own certified specialists who will carry out installation supervision and commissioning of the delivered equipment, as well as further guarantee and post-guarantee maintenance of crushers (mills). They will also provide necessary training and guidance for the customer’s personnel.
Crushers (mills). A brief overwiew
General information and basic definitions. Degree of grinding
The process of mechanical grinding of solid substances may be presented with crushing or milling.
The use of crushed or milled materials contributes for the acceleration of the processes of burning, dissolution, chemical effect, etc., due to the fact that the process material surface increases considerably.
The intensity of the most manufacturing processes directly depends on the size of surface of the process solid materials. By increasing their surface due to decreasing the size of pieces, it is possible to increase the rate of the process itself considerably, to increase the outcome and to improve the quality of the finished products.
The process, at which the pieces of solid materials decrease, is traditionally called crushing or grinding. As a rule, crushing usually means decreasing large pieces. The process, at which fine pieces are ground to smaller particles, is called milling.
Grinding is usually conducted for natural raw material (ores, geological material), fuel (mineral coal), semi-finished and finished products.
Grinding is called coarse if lateral dimension of the process pieces amounts to from 200 to 1,000 millimeters, medium and intermediate, if their size varies from 50 to 250 millimeters, fine – from 20 to 50 millimeters and finish (grinding) - from 3 to 25 millimeters. Grinding may be dry or wet (is performed with addition of the certain amount of water to starting material).
At crushing or milling of pieces of solid materials, large amount of mechanical energy is wasted, so the grinding method should be selected maximally thoroughly.
Degree of grinding
The degree of grinding (i) is the ratio of mean diameter (dн) of the largest pieces before grinding to mean diameter (dк) of the largest pieces obtained after grinding:
i = dн/dк
General degree of grinding is calculated by summing up all the grinding results, which were performed in several stages. In one processing stage, the degree of grinding of large pieces is 2 – 6, medium – 5 – 10, fine – 10 – 50 and the finest – 50 and more.
The particles of both start and processed material are of irregular shape, so for determining diameter parameters, shall be used aperture of screens through which bulk solids are sieved.
Crushing and milling are performed by machines of the most various configurations and size. Grinding of materials may be performed in one or several stages. If the high degree of grinding is required, the process is divided into several stages because one stage doesn’t allow obtaining particles of the required final coarseness.
Grinding is performed by smashing, impact, abrasion and splitting.
In the most cases, combined grinding is used, i.e., for example, smashing is used together with abrasion, and impact is used together with smashing and abrasion. Sometimes, main grinding efforts are supplemented by additional efforts, such as rupture and bending.
At the selection of the grinding method, physical properties of material with the special regard of its solidity and fracture pattern are taken into account.
For especially solid materials, as a rule, impact and smashing are used, for viscous – abrasion, and for fragile materials, the best grinding method is splitting.
The grinding process is characterized by many factors. One of the most considerable factors is the energy consumption. The more solid ground material is, the more consumption of energy is as well.
In crushing processes, the value of effective work may be defined by two existing hypotheses.
According to the first, earlier hypothesis, effective work required for crushing is proportional to the crushed material surface newly formed as the result of crushing.
Physical basics of grinding. Crushing schemes
The principle of deformation of a solid body is the fact that as the result of external forces influence, fractures appear in the weakest body areas. If the fractures close down, the body is exposed only to elastic deformation. If the fractures increase to such an extent that they cross the solid body through the entire section, the body is destroyed. When the strain in the body being deformed exceeds the extreme value, elastic deformation is followed by destruction.
In the process of grinding, the large amount of energy is spent. The theory of the grinding process defines the dependence between the energy spent for grinding, and the result of grinding (i.e. the size of particles of the ground product).
The large energy consumption takes place in the crushing process, so the basic principle of energy saving in the process of material grinding is “grind nothing extra.” This principle supposes the preliminary separation of particles of material equal in coarseness or smaller than the crushing final product. As a result of such filtration, equipment overload is avoided and the product with even coarseness is obtained.
The grinding process may be conducted in the open cycle (the process material comes through the crusher one time) or the closed cycle (the process material is returned many times for repeat grinding). In the open cycle, coarse and medium grinding are performed.
Grinding in the open cycle
The closed cycle is used for finish grinding. The scheme of grinding in two steps (material after processing in the jaw crusher undergoes the test screen sizing procedure and is further fed to the roll crusher) is given below.
Grinding in the closed cycle
Processing (crushing) of materials
Any substance, before being sent for processing or carrying out a chemical reaction, should be duly prepared. That is its form and properties have to be modified to the extent that the manufacturing process flow at all manufacturing steps would be carried out in the best possible way, and the chemical reaction would be successful and provide the maximum product output.
In the chemical industry, for all the processes (physical and chemical) which take place, a very important parameter is the surface area of the materials participating in the process. The result of a chemical reaction performed largely depends on this parameter. Therefore, it is very important to perform the required dimensioning of the particles to provide the optimal flow of this reaction by developing the sufficient contact surface. Many methods, which showed themselves very well in practice, were developed for this purpose.
Grinding of the material
One of such methods is separation of this or that material into smaller parts in order to increase its surface area.
Solid materials, in order to increase their surface area, are exposed to grinding which is performed in special machines, crushers. In case of liquid materials, this may be achieved due to the use of such efficient means as dispersion or irrigation.
The increase of surface area of solid or liquid substances allows to:
- considerably increase the chemical reaction velocity;
- facilitate handling;
- achieve the most perfect form of the product released.
Agglomeration or caking of substances
Turning substances into agglomerates through caking is required, for example, in cases where it is necessary to increase gas impermeability of a heap of bulk solids or to facilitate handling with powder substances. In this case, such agglomeration methods as direct pressing, granulation (shaping substances as grains) and clumping (shaping substances as spheres) may be used.
In case of liquids, the applying joining method is required in the most cases, with the only purpose to unite the discrete liquid drops into the solid phase.
Beside the surface area of materials, the chemical reaction course is considerably influenced by the size of area of adjoining reagents, i.e., the reaction components. Increase of the contact area stimulates more intensive metabolism and, thus, acceleration of the chemical reaction itself.
Grinding of solid substances
Here, grinding means turning large pieces of solid materials into smaller pieces due to the application of mechanical forces.
In the grinding process, the size of particles of substances decreases, and, at the same time, the increase of the specific surface per one volume unit takes place.
Grinding of solid materials is required to achieve various goals, namely:
- To increase the speed of conducting a chemical reaction between the contacting substances. The larger is the surface of substances entering into the reaction, the more intense will be the chemical reaction flow as such.
- For isolation of some specific component from the mixture of solid substances. For example, let us consider ore. As a rule, it is fine-grain mixture consisting of target ore and low-value (gangue minerals etc.) rocks. Grinding of this mixture to a size smaller than the ore particles allows, with the use of magnetic method or flotation, isolating pure ore from it.
- For forming (conditioning) of a product (end or intermediate) for optimal handling or for achieving better fulfillment of this product task.
Existing load types at the grinding of substances
Grinding of substances depending on their physical properties (density, solidity, viscosity, fragility, etc.) is fulfilled with the use of many different load types. As a rule, for solid substances (as well as solid fragile substances), smashing, abrasion, beating, compression or impact-reflective load, for viscous – cutting, for fiber substances – chopping are used. Quite often at processing material in grinding machines, several load types are used at the same time, for example, smashing and abrasion, impact and abrasion, etc.
Destroying and rupture of materials
In the process of destruction of solid and fragile materials by crushing, impact or abrasion, their grains split into many particles of different sizes. At the same time, the formation of one or of two cone zones in which the substance is divided into very fine fragments (fine fraction cones) occurs. The remaining grain falls into fragments of larger size.
As the result of using such grinding method, a very distinct distribution of grains by their coarseness, which is traditionally called the “particle size distribution”, is observed in bulk solids formed.
At grinding with chopping, cutting or sawing of elastic and soft materials, no such distribution is observed.
The basic principles of grinding
At reducing the size of any material, it is required to follow the basic rule: grind nothing extra! On this basis, the following provisions are formed:
- Any material shall be ground only to the degree, which is required for its further use or processing. All the material particles crushed to the desired size should be immediately removed from the machine. Prior to grinding of the material, it should necessarily pass the screen sizing process, i.e., to be sifted on vibrating sieve (screens)
- The grinding process conducted should be “free” as possible - the presence of side processes which complicate it is undesirable because effective work spent on grinding is deemed only overcoming of engaging forces between the particles of material being ground.
- At a large degree of material grinding, the process should be conducted not in one but in several stages.
All the existing grinding machines, regardless of properties of starting materials, the degree of grinding and nature of the efforts applied for grinding, should meet the following basic requirements:
- size of the crushed material pieces should be even;
- crushed pieces of material shall be immediately removed from the operation space;
- dust formation at operation should be minimal;
- discharge should be performed continuously and in automatic mode;
- the possibility to adjust the degree of grinding the materials shall be provided;
- maintainability with the possibility of rapid replacement of worn details with new ones;
- small energy consumption per one production unit.
Classification of machines
All the existing grinding machines are classified by:
- degree of grinding of materials;
- nature of grinding efforts.
The most wide-spread and simple is considered the classification of these machines by the degree of grinding. According to this classification, all grinding machines are united into the following three groups:
- machines performing coarse (preliminary) crushing;
- machines performing medium and fine crushing;
- machines intended for finish grinding (milling).
Coarse (preliminary) crushing
Machines, which perform coarse crushing, also called crushers, are traditionally divided into the following types:
The coarse crushing is used mainly to various coarse materials. The main goal of the preliminary crushing is obtaining the product in the form suitable for its further grinding. The maximal size of pieces of material fed for the coarse crushing depends on the size of the crusher opening (feeding hole). Concerning the degree of grinding, it may vary a little depending on the size of the device opening (outlet). Feed of coarse material to the machine is mainly mechanically.
There are five grinding types in accordance with the original and the final size of material particles:
|Degree of grinding||dn, mm||dc, mm|
|Crushing||Coarse||1500 – 150||250 – 40|
|Medium||250 – 40||40 – 6|
|Fine||25 – 3||6 – 1|
|Milling||Finish||10 – 1||1 – 0.075|
|Superfine||12 – 0.1||0.075 – 0.0001|
Coarse and medium type of crushing is performed by dry method. Fine, finish and superfine processing type may be performed both in dry and in wet way. The advantage of the wet grinding type is reduced dust formation and more identical size of particles obtained.
In accordance with the strength level in the smashing process, materials are divided into the following groups:
|Group of material||Examples of materials||σ, kgf/cm²||σ, Mn/m²|
|Solid||granite diabase||over 500||over 50|
|Medium-hard||lime anthracite||100 – 500||10 – 50|
|less than 100||less than 10|
In the process of material grinding, different efforts are combined. Smashing and impact are combined at coarse and medium crushing, abrasion and impact - for finish grinding. The grinding methods shall be selected according to physical and mechanical properties of process materials:
splitting + abrasion
abrasion + impact
Grinding may be conducted in an open or in a closed cycle. In the first case, the process material passes through the crusher one time. In the second case, material passes through the crusher many times because particles are too large for repeat crushing. The closed cycle is performed by grinding complexes combining mills or crushers with screening devices.
Grinding machines are divided into crushers (for coarse grinding) and mills (for fine grinding).
|Grinding type||Machine type|
|Impact-centrifugal crushers and mills|
|Superfine||Vibrating mills and crushers|
|Vibrating jet mills|
The process material is fed into jaw crushers from the above. After being fed into the device, the material is crushed between the static and the movable jaw. The final crushing product is poured through the outlet between jaws.
The most widely-spread type of jaw crushers is the device with the movable jaw upper suspension axis.
A static jaw in the form of a corrugated plate is placed inside a cast-iron or steel frame. This jaw is made of wear-resistant material. An identical plate is mounted on a movable swinging jaw. The crushing machine operation area is guarded by smooth plates from the sides.
The movable jaw swings due to a con-rod installed on the main shaft. The con-rod and the movable jaw are connected through hinges by spacer plates. As a result, the crank is formed, due to which the greatest force appears in the upper part of the jaws. Smashing of the largest pieces of material occurs there as well. Tension in the moving system and back motion of the jaw are performed by traction and a spring. The outlet size is adjustable. The main shaft ends are equipped with flywheels.
To provide the crushing machine functioning parts from failure, one of the spacer plates is made of two parts. The plate parts are connected with bolts, which are cut, if the load exceeds the permissible pressure level.
The advantages of jaw crushing devices are traditionally considered the structure simplicity and reliability, simplicity of maintenance, wide application, and their small size.
Cone crusher is equipped with a crushing head in the form of a truncated cone, which performs eccentric rotational movements. This head continuously smashes and breaks the pieces of the process material.
At a moment when a crushing head approaches the body, the crushed material falls freely through the part of the ring outlet located between the body and the head.
Cone crushers are divided into two main types:
- designed for coarse and medium crushing (devices equipped with a head in a form of a steep cone)
- designed for medium and fine crushing (devices equipped with a head in a form of a gently sloping cone or “palm crushers”).
In the first type crushing devices, the crushing head has a form of a steep cone and is fixed on the main shaft, which, in its turn, is suspended above on the crosspiece and fixed on the ball bushing. The outlet width is adjustable. An eccentric sleeve is rotated by means of a conical gear. The shaft lower end enters the sleeve freely.
At no load, the shaft with the crushing head performs rotational movements around the eccentric axis, circumscribing the cone surface. The point angle parameters are from 8 to 120. As the result of friction forces in the process of crushing, the shaft and the head are rotated in the direction opposite to the eccentric rotation. Material filling the space between the head and the armor plates, which cover the body surface, is rolled continuously. In this type of crushing devices, the degree of grinding of i = 5-6 is obtained.
These devices are equipped with two parallel cylindrical rolls rotating in opposite directions. Material is ground with rolls by smashing.
The roll crusher device includes not only smooth rolls but also a frame. One roll is movable (mounted in movable bearings), and the second roll is static. The movable roller is held in the certain position with springs. If too solid material is fed to the crusher, the springs compress, thus drawing the rolls apart, and this piece of material passes without damaging the machine. Often, the rolls have an individual drive from a band pulley.
Smooth rolls are used only for medium and fine crushing. The roller main characteristics are its diameter and width.
1- frame, 2- movable roll, 3- static roll, 4- spring, 2e - gap between rolls
Toothed-roll crushers are used for crushing fragile materials of medium-hard (coal, salt etc.). Such rolls grind the material by splitting and smashing because they are able to capture pieces with cross section of ¼ - ½ roll diameter.
The toothed-roll crusher is equipped with low-speed toothed rolls rotating at equal speed (1-1.5 m/s). The guide roll is driven with a band pulley due to gearing. Then, the movement is transmitted to the driven roll.
High-speed rolls are driven by a belt drive. The disadvantage of high-speed rolls is the excessive material grinding.
Impact-centrifugal crushers and mills
The impact-centrifugal crushers include the hammer crushing device into which the process material is fed from the above and is exposed to crushing with hammers on the fly. Hammers are fixed to the rotor on hinges, and the rotor performs quick rotational movements. Hammers discharge material, and it breaks against the body plates. Moreover, material is crushed and abraded on the grate bar. The grinding intensity is adjustable by changing the hammers circumferential speed or the grate opening size. Such crushers are used for coarse and medium crushing.
For fine crushing, sharp light hammers, rotating at high speed (55 m/s), are applied.
The main design elements (hammers, plates, grates) are of high carbon steel, built-up with stalinite.
By number of rotors, hammer crushers may be one-rotor (degree of grinding i= 10-15, the size of crushing product is 10-15 mm) or two-rotor (degree of grinding i= 30-40, the size of crushing product is 20-30 mm). By the principle of location of hammers in one or two rotational surfaces, these devices are single-range or multi-range.
Hammer crushing devices without grating or hammer mills, which are connected to the air separator, are used for fine grinding of low solidity materials (phosphates, lime, ocher etc.). The function of separator is to separate defect product and to return it to the mill.
Disintegrators and dismembrators
Disintegrator is an impact-crushing device equipped with two rotating rotors, between which process material is ground. The rotor is manufactured in the form of a circular disc and has a connection with steel ring fingers. Rows of fingers on one rotor freely enter the rows of fingers on the second rotor. Fingers on the rotors are arranged in the form of the concentric circle. Both rotors have the individual drive and make rotational movements towards each other at high speed.
Material is fed to the device body through a funnel placed at the top. Material is finely ground by impacts of fingers and discs. Processed material is discharged through the grate, which filters pieces of a certain size.
Due to the fact that the disintegrator operates at high speeds, great attention is paid to the issues of foreign materials getting into the device, and installation and balancing of the crusher rotors.
The performance index of such a device is directly related to the material feeding uniformity.
The dismembrator has one rotor and static disc. The mill cover, on the inner side of which the rows of fingers are fixed concentrically, performs the function of fixed disc. The fingers have the form of knives, which allows grinding the material by cutting or rupturing fibers.
The main element of the drum mill is a drum filled with crushing bodies (rods, spheres, rounded pebbles). The drum makes rotational movements and its internal bodies are taken by the friction force on the walls to the certain height. Then they fall and thus grind the material. In this case, the grinding is performed by abrasion and impacts.
There are drum mills of short, tubular and cylindrical-cone type. In short drum mills, L:D = 1.5 – 2, in tube L:D = 3 – 6 (where L – the drum length, D – the drum diameter).
The most widespread variant of drum mills is represented by devices with central discharge through the hollow journal or with end discharge through the membrane. The devices with peripheral discharge through the drum holes are less popular.
Short type drum devices often have a closed operation cycle and are equipped with a classifier, which filters the pieces of material requiring additional grinding. The closed operation cycle allows increasing the performance index and reducing energy costs.
Drum mills can perform both dry and wet grinding. Grinding of material corresponds to i = 50 -100.
In mills of this type, material is ground by rollers or balls (grinding bodies) which roll along the ring inner surface and are pressed against it by centrifugal force.
The balances with rollers are freely suspended on the shaft top at the crosspiece. Their number may vary from 2 to 6. By rotating, rollers are pressed against the stationary liner. The material fed is transported between the rollers and the ring liner. At the bottom of the mill machine chamber, fraction settles which remains large and non-ground. Wherefrom, it is thrown upward by a scraper in front of oncoming rollers.
Air is supplied to the lower chamber compartment. This air hoes the ground material and feeds it to the separator. From there, ground product comes to the cyclone. Large fraction repeatedly comes to the mill for additional milling. Blade mills have the performance of 20 metric tons per hour.
Such type of devices is used for finish grinding of pigments and fillers (talc, chalk, etc.).
Ring mills are characterized by compactness and wide range of degrees of grinding.
Crushers and mills for superfine grinding
The more frequently external forces affect the process material, the less fractures manage to “heal themselves.” The most economy-type fine grinding method is vibrating impact on the material. With the use of this method, material fatigue breakdown occurs due to frequent but relatively weak impacts on material particles.
In the process of operation of such devices, please pay attention to the fact that the crushing device itself is also exposed to elastic deformation and destruction.
A vibrating mill of inertial type has a cylindrical body filled with the process material, and grinding bodies by 80-90%. The body rotates on the shaft, and the shaft is equipped with an unbalance. An unbalance is located eccentrically relative to the mill rotation axis, due to which, during rotation of the unbalanced mass of the shaft with the unbalance, centrifugal inertial forces appear which cause the crusher vibrating. In the process of rotation, the body with all its contents inside oscillates in a plane perpendicular to the oscillator axis, at a practically circular trajectory.
The body oscillation frequency corresponds to the number of shaft revolutions, which is in the range of 1,000 – 3,000 rpm. The oscillation amplitude varies from 2 to 4 mm. In these devices, the intensive material grinding occurs.
In order to reduce vibrating in the workshop, the mill body leans on springs and wooden linings. Moreover, the electric engine is connected to the sleeve with a flexible shaft.
In order to control the temperature within the mill, oscillators are regularly cooled with water circulating through the jacket.
This type of devices performs dry and wet grinding and is able to operate continuously or periodically. Mills operating continuously function in the closed cycle with the air separator.
Such devices are reasonable to be used for ground materials with the diameter of particles dn not exceeding 1-2 mm until the final diameter dk less than 60 µm.
Vibrating (reflecting) crushers are equipped with a filtering mesh through which the process material comes. The mesh sifts out fine elements, after which the material is fed to the rapidly revolving (12-70 m/s) roll. The roll is equipped with vanes, which capture the material and throw it on the shield. The material elements impact each other, shield, body and vanes. As the result, final grinding of material takes place. The degree of grinding reaches i = 20 – 30.
The advantages of devices of this type traditionally include high performance, low specific energy consumption, simplicity of construction and lightweight, and easiness of installation.
For superfine grinding, beside oscillation installations, colloid mills are widely used. By the principle of action, they are similar to ring-roll or impact-centrifugal mills. In such devices, material is ground by passing through the gap between a rapidly rotating rotor (V-roller) and a stator (ring expanding upwards). The gap may also be situated between the rotor disc fingers, which are arranged in concentric circles and the mill body. Such devices operate at a very high rotor speed level (up to 125 m/s) and are used mostly for wet grinding.
To achieve high grinding fineness and obtain particles with the size of less than 1 micron, grinding is carried out in mills of colloid type. Material is ground in these mills by dry or wet milling friction or impact methods.
A mill of this type includes a body with a groove in its middle. The cone groove is of shape, and it includes a rotating rotor. Between the groove and the rotor, a narrow gap is provided (min. 0.05 mm). Through the opening in the groove, the material is fed to the gap between the groove and the rotor, which is adjustable with a micrometer screw; solid particles are abraded, coming out through the outlet with the liquid. The rotor is driven by an electric engine through the pulley.
There exists another type of colloid mills. Such mills operate according to impacts of fingers on suspension principle. They consist of a cylindrical body inside of which a disc rotates at high speed. On both sides of the disc, the fingers are situated. The suspension is fed to the mill through the spout, where it is exposed to impacts by the fingers, and comes out through the spout.
The pump delivers suspension from the collecting to the mill through pipeline. Material shall be fed to the mill at low speed. This speed should differ considerably from the circumferential speed of the impact fingers. As a rule, the speed at material loading into the mill is equal to 0.7 meters per second, and the disc peripheral speed is 190 meters per second.
The wet grinding method is the most widespread and available in the preparation of colloidal solutions. The dry grinding method doesn’t provide the appropriate degree of fineness in order to obtain particles of colloidal size. The centrifugal-ball mills of colloidal type are used for finish dry grinding. They apply a large number of balls with the diameter of 8 - 15 mm. Balls are scattered at high speed, break the material, which passes the same route as these balls. The finished ground product comes out after passing through the air separator.
Abrasion mills, for example, roller mills, are equipped with a revolving bowl with two or more cradles of cylindrical form continuously moving within it.
Cylindrical cradles, firmly pressed by the elastic springs to the runner track, grind the pieces of the material fed to the center by their b compression and abrasion. At this, the product moves under the rollers to the bowl edges, after which it is fed to them again by scrapers and guide vanes and is ground repeatedly.
The ground product is blown upwards with a b air stream flowing along the edge of the bowl, and enters into the air separator, then into the centrifugal separator located outside the mills, and is deposited there. The large particles are retained in the machine air separator and then return to the runner track where they are exposed to the repeat grinding. All abrasion mills are able to perform coarse and fine grinding of very different materials, from solid to very soft.
The construction of spiral and jet mills is such that compressed air supplied from their nozzles at high velocity (up to 600 m/s) catches the loaded material and carries it to flat cylindrical chamber. Inside it, a b rapidly revolving flow is formed. It goes from the perimeter by spiral to the outlet situated by the center. Starting material, coming into the chamber at high relative velocity, collapses with a b spiral flow or with a wall, thus breaking into very small particles.
Shearing and cutting mills
Shearing and cutting mills are able to grind different substances: soft, elastic and viscous. They are equally good in grinding scrap paper, pieces of plastic, rubber (old tires) and textile, wood waste used for producing particleboards. There are several design variants of these machines.
Rotary cutting mills are equipped with the rotor with a knife ring, which rotates in the machine body relative to stationary knives fixed on its inner surface. Starting material fed from the above comes into the operational space of the machine and is ruptured into pieces by rotary knives. Then, it is ground in space between the stationary and movable knives by cutting. Fine product comes out of the aggregate through the fine mesh, and large pieces of material will remain in the mill and be cut by its knives until they achieve the degree of grinding sufficient for coming through the mesh holes.
Comparison and choice of crushing and milling machines
The choice of crushers depends on two main aspects: grinding type and physical and mechanical properties of the process material.
For coarse crushing, jaw crushers are the most convenient. Cone crushers are also applied for coarse crushing, but due to their complex structure and large weight, it is reasonable to apply such devices in large-scale industries, because one cone crusher is able to replace two and more jaw machines.
Palm crushers considerably outproduce roll crushers, but the last are compact, simple and reliable, due to which they are applied more frequently. For works with fragile materials, toothed roll crushers are the best choice.
Disintegrators are the optimal decision for grinding damp materials of low solidity.
Ball mills are used for finish grinding. Ring-roll mills are used for work with materials of low solidity.
Vibrating mills perform the superfine crushed product, upon the condition of preliminary grinding of the material in the crushers of other types to 2 mm.
Vibrating jet mills are not widely spread but they are the most optimal for work with such materials as mineral coal, dry coloring agents, titanium dioxide, etc.
- Agitators, mixers
- Ball tube mills
- Cone crushers
- Edge runner mills
- Equipment for cleaning oil and gas pipelines
- Feeders (dosing equipment)
- Gas / liquid density measurement instruments and equipment
- Hammer mills (crushers)
- Industrial electrical and gas generators
- Jaw crusher
- Mixing equipment (plants)
- Roll crushers
- Vibrating mills and crushers
Upon becoming the official distributer of crushers (mills), our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), carries out the following: finds the buyers of your products on the market, conducts technical and commercial negotiations with the customers regarding the supplies of your equipment, concludes contracts. Should a bidding take place, we will collect and prepare all the documents required for the participation, conclude all the necessary contracts for the supply of your equipment, as well as register the goods (crushers (mills)) and conduct customs clearance procedures. We will also register a certificate of transaction (Passport of Deal) required for all foreign trade contracts in the foreign currency control department of the authorized Russian bank so that currency transaction could be effected. If required, our company will implement an equipment spacing project in order to integrate your equipment into the existing or newly built production plant.
We are convinced that our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will become your reliable, qualified and efficient partner & distributor in Russia.
We are always open for cooperation, so let’s move forward together!