Twin shaft mixer. The essence and purpose of the mixing process

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INTRODUCTION

For mixing clay during semi-dry and plastic molding ceramic products Single-shaft and twin-shaft paddle mixers of continuous and cyclic action are widely used.

Mixers of this group are used both for preparing a charge from several components, and for preparing a homogeneous mass in dry form or with moisture. Humidification can be done with water or steam low pressure. In the latter case, a higher quality of products is achieved, since the steam heats the mass and then, condensing, moisturizes it. The main parameter of paddle mixers is their performance.

In paddle mixers continuous action the blades are fixed to the shaft along a helical line, which ensures simultaneous mixing and movement of the product along the shaft.

To provide required quality When mixing bulk products in a continuous paddle mixer, the optimal mixing time is experimentally established, which should correspond to the time of movement of bulk products in the mixer from the loading point to the unloading point. This time can be changed by changing the number of revolutions of the shaft with the blades, as well as the angle of rotation of the blades relative to the shaft. paddle mixer ceramics mixing

The SMK-18 mixer is used in factories producing bricks, tiles and other building ceramics products with the initial characteristics of clay raw materials:

Humidity 5-20%;

Temperature - not less than + 3 0 C.

1. TECHNICAL CHARACTERISTICS

Productivity (at a mixture density of 1700 kg/m3)

Working shaft speed

Diameter described by the blades

750 mm

Installed power

30 kW

dimensions

5400 mm

1800 mm

1620 mm

Mixer weight

3500 kg

2. ESSENCE AND PURPOSE OF THE MIXING PROCESS

The twin-shaft paddle mixer is designed to create a homogeneous and evenly moistened mass. Two blade shafts rotating in a trough. The blades are located along a helical line. In a direct-flow mixer, both shafts, when rotating, move the material in one direction and mix. Steam is supplied to the mass from below through a scaly bottom so that the holes do not become clogged with clay. In this case, part of the clay turns into slip, which is collected in containers (mud collectors) located under the scaly bottom.

Trajectory of the mixed mass: loading hole, trough, shaft blades, humidification with steam and/or water. Used in the production of clay bricks using the plastic method.

Advantages:

Continuous equipment;

Availability of steam humidification;

Warming up, increasing the plasticity of the mass.

The disadvantage is the complex design.

The mixer consists of a trough-shaped welded body, driven and driven shafts with blades and a drive. The rotation of the shafts is transmitted from the electric motor through a friction clutch, gearbox, coupling and spur gear located in a closed box. Steam is supplied through the bottom of the housing and condensate is discharged. The lower part of the case is protected by thermal insulation and a casing to retain heat. In the upper part of the body there is a perforated pipe for irrigation of the mass with water. The clay mass is fed through the loading hole in the upper part of the body, and then mixed by blades rotating towards each other, which move the mass to the discharge hole located at the bottom of the body. When stirring, the mass can be moistened with water or steam. The speed of movement of the mass to the unloading hatch, and therefore the productivity of the mixer, depends on the angle of rotation of the blades of the mixing shafts. As the rotation angle increases, the mixer's performance also increases. At the same time, the quality of mixing the mass depends on the angle of rotation of the blades. As the angle of rotation of the blades decreases, the quality of mixing the mass improves.

The mixer is used in factories producing bricks, tiles and other building ceramics products.

3. TECHNOLOGICAL PROCESS FOR PRODUCTION OF PRODUCTS FROM GRUFIGHT OF CERAMICS

Production of ceramic wall materials Based mainly on the use of plastic molding and semi-dry pressing technology. Last years The technology of plastic molding from ceramic masses of low humidity using coal preparation waste is becoming widespread.

The traditional technology of plastic molding from a clay mass with a moisture content of 18-24% assumes the presence of the following main stages in brick production: preparation and processing of the clay mass with additives (lean and burnable), molding, cutting timber and laying the raw material on vehicles for drying, firing and packaging finished products (Fig. 1.1).

When extracting and processing clay mass, a multi-bucket excavator, a clay ripper, a box feeder, runners, rollers, and mixers are used.

The installation sequence of the listed machines depends on the type of products, rheological and structural properties raw materials. Stable operation of the entire line is ensured by the use of mechanized charge storage facilities, which make the operation of the equipment complex independent of the supply of raw materials from the quarry and improve the quality of products. Screw belt presses are used for molding products, and single-string and multi-string cutting machines are used for cutting timber. Thin-walled, high-quality clay products that require vacuum processing are formed using vacuum presses, which are usually combined with a mixer. Without vacuum presses Usually used for molding solid bricks.

The equipment that ensures the laying of raw materials on vehicles for drying and firing largely depends on the type of dryers and kilns. The most common are chamber, tunnel and conveyor dryers. When using low-capacity dryers, the raw material is placed on slats and frames (wooden and aluminum) or on pallets. Depending on the type of dryer used Various types trolleys on which products are dried. To transfer drying trolleys from dryers to kilns and return empty trolleys to their original position, electric transfer trolleys of various types are used designs. The design of the machines that ensure unloading of drying trolleys and loading of dried products onto kiln trolleys, as well as the shape and number of stacks on it, depend on the size and type of kilns. To move loaded and empty drying and kiln trolleys both outside the dryers and kilns and inside them, pushers and carts are used. Finished products are unloaded from 15 kiln cars and packaged using automatic unloaders and packers, which ensure that the transport package is tied with tapes for transportation to the construction site.

A type of plastic molding of wall materials is molding from a clay mass of low humidity. It is provided by screw presses with a drive power that significantly exceeds the drive power of presses that form products from clay mass of normal molding humidity. If the mechanical strength of the raw material allows, then the raw material is placed on a kiln trolley to combine drying and firing.

Resource-saving molding technology using coal enrichment waste is becoming widespread (the degree of waste utilization is up to 100%). In this case, the production line includes, along with the traditional set of equipment, special machines for processing coal preparation waste and special-design screw vacuum presses with a high-power drive.

A distinction is made between plastic molding with clay powder obtained using semi-dry pressing technology. The powder is mixed in a mixer with additives, moistened and fed into a screw press.

An analysis of the operation of domestic and foreign equipment complexes shows that the technical level and the main design and technological features of the equipment are determined by the method of laying raw material on drying and kiln vehicles. Various technological plastic molding lines, equipped with various equipment, can be divided into four groups according to the installation method: with rack (frame), pallet, shelf, stack drying.

Rice. 1.1. Technological scheme for the production of ceramic bricks by plastic molding:

1 -- multi-bucket excavator; 2 -- tilting trolley; 3 -- electric locomotive or dump truck; 4 -- crusher; 5 - roar; 6 -- feeder; 7 -- clay mixer; 8 -- mixer; 9 -- belt screw press; 10 -- automatic cutting and laying of raw materials on drying trolleys; 11 -- drying trolley; 12, 17 -- electric transfer trolley; 13, 18 -- pushers; 14 - dried; 15 -- stove trolley; 16 -- automatic reloading of dried bricks onto a kiln trolley; 19 -- tunnel oven; 20 -- automatic kiln trolley unloading and packaging; 21 -- wet-ground runners; 22 -- stone separation rollers; 23 -- box feeder; 24 - clay ripper.

Comparison of complexes based on in various ways drying and firing, indicates that the transition from low-capacity drying trolleys (slats and frames) to more capacious ones (pallets) creates favorable conditions for the operation of transport systems, ensures the achievement of a higher technical level of equipment and better technical and economic performance indicators of the complex as a whole.

In Fig. Figure 1.2 shows a diagram of the production of bricks using the semi-dry pressing method. The technological line ensures the sequential execution of the following operations: clay extraction, drying, grinding, preparation of additives, mixing and moistening the mass. The powder is compressed in a mold of a mechanical or hydraulic press, and the raw material is stacked on a kiln trolley for firing and, if necessary, drying. The fired products are unloaded, packaged and sent to the construction site.

A variation of the semi-dry pressing method is a resource-saving pressing method using coal preparation waste, in which waste preparation machines are included in the production line.

In addition, semi-dry pressing is used using the slip method for preparing press powder. In this case, a spray dryer is introduced into the production line, which ensures the production of clay powder with a moisture content of 8.5-9.5%. The powder is prepared by dissolving quarry clay, cleaning the resulting slip from foreign inclusions and spraying the slip with drying.

Rice. 1.2 Technological diagram for the production of ceramic bricks using the semi-dry pressing method:

1 -- trolley or dump truck; 2 -- box feeder; 3 -- stone separation rollers; 4,6,9 -- conveyors; 5 -- drying drum; 7 -- plate feeder; 8 -- clay reserve; 10 -- dry grinding runners (disintegrator or mill); 11 -- elevator; 12 -- vibrating sieve; 13 -- bunker; 14 -- feeder; 15 -- mixer (humidifier); 16 -- a press with a stacker of raw material onto a kiln trolley; 17 -- stove trolley; 18 - dried; 19 -- power transmission trolley; 20 -- pusher; 21 -- tunnel oven; 22 - automatic unloader and packager.

4. DESCRIPTION OF THE DESIGN OF A DOUBLE-SHAFT BLADE MIXER

Clay and additives in a given proportion are continuously loaded into mixers and mixed by rotating blades mounted on shafts, which simultaneously advance the mixture to the discharge hole. The mixing speed and mass processing are adjusted by changing the angle of the blades.

If the productivity of the mixer exceeds the productivity of subsequent clay processing and molding machines, then the number of shaft revolutions is reduced to eliminate frequent stops.

Better mixing and processing of plastic masses is obtained when the mass filling the mixer body covers the shafts, but not higher than 1/3 of the height of the blades in the upper position. The distance between the end of the blade and the wall of the mixer trough should not be more than 2-3 cm. When operating the mixer, it is necessary to ensure that the mixture components are supplied evenly. The mixer must not be overloaded.

The mixer body must be covered with a metal grill. It is prohibited to stand on it or push the mass through the grate with any object. You can take a clay sample from the mixer while it is running only with a special scoop. During operation, it is not allowed to open the lid and remove the grill.

Before stopping work, first turn off the machines feeding the material into the mixer, and after the entire mass has been exhausted, turn off the electric motor and the device transporting the processed material.

At the end of the shift, the shaft with knives and the mixer body must be cleaned of adhering mixture from the internal and outer sides. When the mixer blades wear out, they must be replaced or overlaid with wear-resistant alloys OI-15 and OI-7. The use of these alloys increases the service life of the blades by more than 5 times.

5. COMPARATIVE CHARACTERISTICS OF MACHINES AND EQUIPMENT FOR MIXING CLAY MASSES

Equipment characteristics

NAME EQUIPMENT

Twin-shaft paddle mixer SMK 125A

Twin-shaft paddle mixer SMK 126A

Twin-shaft paddle mixer SMK 125B

High-speed paddle mixer SMS 95A-1 (with rubber body)

High-speed paddle mixer SMS 95A-1 (with metal body)

Twin-shaft mixer SM 727A

Twin-shaft paddle mixer SMK 125B

Productivity, t/h

Diameter of the circle described by the blades, mm

Distance between the axes of the blade shafts, mm

Filler size, mm, no more

Shaft (drum) rotation frequency, s-1

Power, kW, no more than the drive (rotor) of the skip hoist

Rotation speed, rpm, no more

Overall dimensions, mm

length

width

5250

1670

5900

1700

3642

1600

6830

1700

6830

1700

3165

975

3470

1460

Overall dimensions without drive, mm

length

width

3670

1252

4260

1392

5000

1612

5000

1612

2770

740

Weight, kg

general

without drive

3200

4400

3000

7750

7400

1000

2650

6. DESCRIPTION OF THE INSTALLATION OPERATION

A continuous twin-shaft paddle mixer consists of a trough-shaped body 2, covered with a lid 1, in which horizontal shafts 3 are placed, with blades 5 installed on them. The shafts are driven towards each other by an engine 10, through a friction clutch 9, a gearbox 8 and a gear pair 7.

The blades are installed at angles at which the optimal ratio of circumferential and axial velocities of particle movement is achieved, which ensures the required time for the components to pass from window 6 to unloading hatch 15 and, consequently, the quality of mixing.

To moisten the mixture, steam enters through the gaps in the scaly bottom 14, which is supplied through pipe 13 through distributors 12. To reduce heat loss, the lower part of the body is closed with a casing 11 filled with mineral wool. The mass can also be moistened with water supplied through collector 4.

The mixing process in continuous mixers is carried out by mechanical action on the components of the mixture of rotating blades while simultaneously moving the mixed mass from the loading point to the unloading point.

The working body of mixers is one or two horizontal shafts rotating towards each other with blades attached to them along a helical line. Mixing is carried out inside a metal stationary body of a grooved shape.

7. CALCULATIONS OF BASIC PARAMETERS

The productivity of continuous mixers with horizontal blade shafts is determined by the speed of movement of materials along the axis of the housing and its cross-sectional area and in general can be written as follows:

Where Q v- speed of movement of the material along the mixer body, m/s; A- cross-sectional area of ​​the material flow, m2.

With some assumption, the working body of such a mixer can be considered as an auger with an intermittent screw. In this case, the axial speed of movement of the material can be determined from the expression

Where k vz - mixture return coefficient for the blade, equal to 0.6...0.75; d- number of blades within one helix pitch; S- blade helix pitch, m; b - angle between the plane of the blade and the plane normal to the axis of the mixer shaft, b = 10...45 0; n- shaft rotation, s -1; R n- outer radius of the blade, m.

Square A, m2, cross-section of the material flow with a sufficient degree of accuracy:

Where ts- filling factor of the mixer body equal to 0.5... 0.8.

Substituting the values A And v into the formula, we get the following expression to determine performance Q, m 3 / h:

In continuous mixers with horizontal shaft blades, power is expended to overcome the following resistances: 1) friction resistance of the mixture against the walls of the housing; 2) transportation of the mixture to the unloading site; 3) cutting the mass of the mixture when mixing it; 4) friction resistance in drive parts and assemblies.

Power , to overcome the frictional resistance of the mixture against the walls of the housing during mixing and transportation can be determined with sufficient reliability using the formula, kW,

Where Q- mixer productivity, m 3 /h; R- volumetric mass of the mixture, kg/m3; g- free fall acceleration, m/s 2 ; w - coefficient of resistance to movement of the mixture, recommended within 4...5.5; / - working length of the mixer body, m.

Power R 2 , kW required to cut the mass of the mixture with the blades as they rotate is determined by the expression:

Where To R - resistivity cutting mixtures, for cement concrete mixtures k = (3.0 ... 6.0) -100 2 Pa; b- average blade width, m; i is the number of blades simultaneously immersed in the mass of the mixture on one shaft; z - number of blade shafts; R„, R b - outer and inner radius of the blade; m; - angular velocity of the blade shaft, rad/s, =2pp.

The power consumption for determining the friction resistance in the drive units and parts is taken into account when calculating the efficiency, which is either calculated or accepted within the range of 0.65 ... 0.85.

Then the required engine power P dv for this mixer:

Performance and power indicators are almost the same. The tabular value for SMK-18 productivity is 50 m 3 / h, and according to our calculations it turned out to be 46 m 3 / h. The table value for SMK-18 power is 30 kW, but according to our calculations it turned out to be 26 kW. This is explained by the fact that we cannot take into account all factors and take accurate data for calculations.

Let us determine the annual productivity of the mixer with two shifts of eight hours and 247 working days a year.

8. OCCUPATIONAL SAFETY AND ENVIRONMENTAL PROTECTION MEASURES

Pollutants coming from enterprises producing ceramic products, depending on specific technological processes, can be released into the air or through waste water. water bodies and accumulate on the surface of the earth in the form of waste. Impact on environment also cause noise and unpleasant odors. The nature and level of air pollution, the amount of solid waste and wastewater depend on various factors, in particular, on the type of raw materials, auxiliary substances, fuel used, as well as on the production method:

* air emissions: during the production of ceramics, dust/particulate matter, soot, gaseous substances (carbon oxides, nitrogen oxides, sulfur oxides, inorganic fluorine and chlorine compounds, organic compounds, heavy metals) may be released.

* wastewater discharges: mostly contain mineral (suspended particles) and other inorganic components, a small amount of various organic matter, as well as heavy metals

* technological losses/production waste: waste from the production of ceramic products mainly consists of various sediments, broken products, spent gypsum molds and sorbing agents, dry residue (dust, ash) and packaging waste

* energy consumption/CO2 emissions: all ceramics industries consume significant amounts of energy as the main process steps involve drying and subsequent firing at temperatures ranging from 800 to 2000 °C. Currently, in EU member states, mainly natural and liquefied gas (propane and butane), EL grade fuel oil are used for roasting; in addition, heavy fuel oil, liquefied natural gas, biogas / biomass, electricity and different kinds solid fuel(coal, petroleum coke).

It follows that during the production of ceramics, all types of pollution occur. There are many ways to clean them.

The main conditions for improving the environment in the country are: rational use, protection and waste of natural reserves, ensuring environmental safety and anti-radiation measures, increasing and developing environmental thinking among the population, as well as control over the environment in industry. Environmental protection at the enterprise has identified a number of measures to reduce the level of pollution generated by enterprises:

Identification, assessment, continuous monitoring and control of release harmful elements into the atmosphere, as well as the creation of technologies and equipment that protect and conserve nature and its resources. Development of legal laws aimed at environmental protection measures and material incentives for fulfilling requirements and preventing a set of environmental measures. Prevention of the environmental situation by identifying specially designated areas (zones). In addition to the environmental safety of the facility (environmental protection at the enterprise), life safety (LS) at the enterprise is no less important. This concept includes a complex organizational enterprises And technical means to prevent the negative impact of production factors on humans. To begin with, all employees of the enterprise attend a safety course that instructs immediate superior or occupational safety worker. In addition to simple safety precautions, workers must also comply with a number of rules according to the technical requirements and standards of the enterprise, as well as maintain sanitary and hygienic standards and the microclimate in the workplace. All norms and rules of environmental and work safety must be defined and recorded in a specific document. The environmental passport of an enterprise is a comprehensive statistics of data reflecting the degree of use of natural resources by a given enterprise and its level of pollution of adjacent territories. The environmental passport of an enterprise is developed at the company’s expense after agreement with the relevant authorized body and is subject to constant adjustment in connection with repurposing, changes in technology, equipment, materials, etc. For correct drafting company passports and content control to avoid fraud harmful substances The nature surrounding the enterprise is monitored by a special environmental control service. Service employees are involved in filling out and processing all fields of the environmental passport, taking into account the total impact of harmful emissions into the environment. In this case, the permissible concentration levels of harmful substances in the areas adjacent to the enterprise, air, surface layers of soil and water bodies are taken into account.

CONCLUSION

The invention relates to equipment for the production of building ceramics (bricks, tiles), namely to devices for preparing ceramic mass for molding by mixing, processing and, if necessary, cleaning it from foreign inclusions.

To prepare the ceramic mass for molding, two devices are usually used sequentially installed one after another: a mixer for mixing the components at the macro level (evenly distributing them throughout the volume), a screw blower with a filter grid for processing the ceramic mass and cleaning it from foreign inclusions. Moreover, mixing is carried out in a two-shaft paddle mixer, which is significantly more efficient than a single-shaft mixer.

This division of the process makes it possible to provide rational technological and design parameters for each device, but the presence of two devices with drives, control systems, frames, etc. reduces the technical and economic indicators of this stage of the technological process, increasing the dimensions of the equipment, metal consumption, labor intensity of maintenance and repair.

LIST OF REFERENCES USED

1. Construction machines T.2. Equipment for the production of building materials and products. M.N. Gorbovets, 1991. - 496 p.

2. Technology of building ceramics. I.I. Moroz, 1972. - 416 p.

3. Mechanical equipment of enterprises of building materials, products and structures. M.Ya. Sapozhnikov, 1976. - 384 p.

4. Machinery and equipment for ceramics and refractory plants. A.P. Ilyevich, 1968. - 355 p.

5. Construction machines. Directory. In 2 volumes. F.A. Lapeer, 1977.-491 p.

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Owners of patent RU 2622131:

The invention relates to equipment for mixing bulk products and can be used in the feed industry, agricultural enterprises and other industries.

A well-known high-speed single-shaft paddle mixer DFML "SPEEDMIX" from Buhler, Switzerland (magazine "Feed internation". - No. 8. - 1996. - P. 25-26) for mixing bulk products, including a mixing chamber, a shaft with four blades that provide countercurrent movement of products with a mixing time of 90 s. The quality and time of mixing the mixture components are directly proportional to the number of blades and their rotation speed.

The disadvantage of this mixer is high frequency rotation of the blade shaft, due to the small number of blades, which leads to significant energy costs.

A known twin-shaft intermittent paddle mixer from Forberg, Norway (Norwegian Patent No. 143519, B01P 7/04 dated September 15, 1976), including a mixing bath, two horizontal paddle shafts that rotate in opposite directions. The working body of the mixer has 24 blades, 12 on each shaft with different angles rotation relative to the shaft axis. At the end walls there are four blades with a rotation angle of 0 degrees and four blades with a rotation angle of 55°, the remaining 16 blades have a rotation angle of 45°. The rotation trajectories of the blades of one shaft intersect with the rotation trajectories of the blades of the other shaft.

When the mixer operates, the paddle shafts move the product in four different directions to form homogeneous mixture within 40 s.

The disadvantage of the design of this mixer is: the complexity of the design of the working body, due to the presence of a large number of blades, which significantly increase the energy consumption spent on overcoming the large forces that arise in each blade when they enter and exit the product during the mixing process; mandatory synchronization of the rotation of the blade shafts, in which each row of blades of one shaft fits between two adjacent rows of blades of the other shaft. Failure to synchronize the rotation of the blade shafts causes jamming of the mixer working body, which causes breakage of the blades, shaft and drive.

The closest in technical essence and achieved effect is the mixer (Utility model patent No. 61588, B01F 7/04. Mixer. Afanasyev V.A., Shcheblykin V.V., Kortunov L.A. Applicant OJSC All-Russian Scientific Research Institute feed industry"), including a mixing bath, two shafts with blades, a drive, characterized in that in order to simplify the design, reduce metal consumption and increase operational reliability, 12 blades with rotation angles of 45° relative to the shaft axis are installed on the blade shafts, while on the first on the shaft there are six blades arranged in a helical spiral at 120° intervals, three blades with the right direction of the spiral, and three others with the left direction; on the second shaft there are also six blades arranged in similar helical spirals with left and right directions. The blade shafts are installed at a distance equal to twice the height of the blade with the stand, at which the rotation trajectories of the blades of each shaft do not intersect.

The disadvantages of the known mixer are the significant energy consumption spent on overcoming the large forces when the blades enter the product; long mixing time due to low turbulent flow of mixed components.

The technical objective of the invention is to increase mixing efficiency and reduce specific energy costs while achieving the best mixing uniformity through the implementation of a progressive mixing method based on mechanical fluidization in combination with cross-counterflow, as well as reducing the duration of the mixing process.

This goal is achieved by the fact that in a twin-shaft mixer, including a mixing bath, two shafts with blades, a drive, while the blades mounted on the shafts are rotated 45° relative to their axis, and on the first shaft the even blades are arranged in a helical spiral through 120° with the right the direction of the spiral, and the odd blades - with the left, on the second shaft there are also even and odd blades along similar helical spirals with left and right directions, inside each hollow blade shaft a fixed axis is coaxially installed, on which with a pitch equal to the pitch of the blades on the blade shaft, cams installed, with outer surface which interact with rollers installed at the ends of the blade struts, and on the struts located between internal diameter blade shaft and rollers, springs are put on, top part the mixing bath body is made along a complex line corresponding to the movement path of the blades, determined by the outer surface of the cams, the upper edge of the blade in contact with inner surface mixing bath, made of elastic material; nozzles for supplying liquid and viscous components are installed in the end walls of the upper part of the mixing bath body.

In fig. 1 shows a frontal view of a twin-shaft mixer; in fig. 2 - top view of a twin-shaft mixer; in fig. 3 - side view (left) of a twin-shaft mixer; in fig. 4 - section A-A front view of a twin-shaft mixer; in fig. 5 - section of the blade shaft and view A of the blade shaft; in fig. 6 - photo of a twin-shaft mixer; in fig. 7 - computer version general view twin-shaft mixer; in fig. 8 - three-dimensional image of the left and right shafts of a twin-shaft mixer; in fig. 9 - diagram of the rotation of the left and right shafts of a twin-shaft mixer.

The twin-shaft mixer (Fig. 1-3) contains a mixing bath 1 with end walls 2 and 3, a loading pipe 16, a discharge pipe 17, horizontal hollow blade shafts 4 and 5 rotating in the opposite direction, a drive 6 for rotating the blade shafts 4 and 5 and drive 7 for unloading the finished mixture from the mixing bath. The proposed design of the drive 6 of shafts 4 and 5 from one electric motor using a belt drive and two parallel-operating gearboxes ensures synchronized rotation of the blade shafts 4 and 5. In this case, shaft 4 rotates clockwise, and shaft 5 counterclockwise (Fig. 9).

Blades 10 with stands 12 are installed on shafts 4 and 5, at the ends of which there are rollers 13 (Fig. 5). On the racks 12, located between the inner diameter of the hollow blade shaft and the rollers 13, springs 11 are put on. For ease of installation and maintenance of the springs 11 and rollers 13, holes are drilled in the shafts 4 and 5 into which bushings 14 are screwed along the thread (Fig. 5).

Inside each hollow blade shaft 4 and 5, fixed axes 8 are installed coaxially, on which cams 9 are installed with a pitch equal to the pitch of the blades 10 on the blade shaft.

Rollers 13 installed at the ends of the struts 12 of the blades 10 interact with the outer surface of the cams 9.

The upper part of the body of the mixing bath 1 is made along a complex line corresponding to the trajectory of movement of the blades 10, determined by the outer surface of the cams 9 (Fig. 4).

The upper edge of the blade 10, in contact with the inner surface of the mixing bath 1, is made of elastic material.

Blades 10 are installed on shafts 4 and 5 with a rotation angle of 45° relative to the axis of the shafts (Fig. 5). Moreover, on shaft 4, even blades are located in a helical spiral through 120° with the right direction of the spiral, and odd blades are located in the left direction; on the second shaft, even and odd blades are also located in similar helical spirals with left and right directions (Fig. 8 and Fig. 9). Installation of blades 10 on the shaft 4, rotating along a trajectory that does not intersect with the rotation path of the blades 10 of the shaft 5, increases operational reliability and additionally turbulizes the flow of mixed components of the mixture (Fig. 8 and 9).

In the end walls 2 and 3 of the upper part of the mixing bath 1, nozzles 15 are installed for supplying liquid and viscous components.

The proposed mixer works as follows.

The initial bulk components are loaded into the mixer through the loading pipe 16. The drive 6 is turned on, and the shafts 4 and 5 are rotated towards each other.

Due to the arrangement of even blades on shafts 4 and 5 along a helical spiral through 120° with the right direction of the spiral, and odd blades with the left, the movement of the mixture components in bath 1 of the mixer has the form of a cross countercurrent, because they ensure the direction of movement of the mixture flows towards each other in the direction from the end walls to the center of the mixer.

10 blades on base experimental research It is recommended to install at an angle of 45° to the horizontal axis of shafts 4 and 5, since the mixing intensity is created by the formation of powerful countercurrent flows of the mass of the mixed mixture. When the angle of rotation of the blades decreases to zero, the linear movement of the mass of the mixture decreases and stops at 0°, the resistance of the medium and the circumferential rotational movement of the particles increases, and when the angle of rotation of the blades increases to 90°, the resistance of the medium decreases, but the intensity of movement of the particles also decreases. It was also taken into account that at a blade rotation angle of 45°, the most optimal consumption of electrical energy was ensured.

The defining parameter of the mixer is the swing radius of the blades. The circumferential speed of the blades 10 on shafts 4 and 5 depended on the size of the radius, and as our studies showed, it is better to make it variable, which directly influenced the nature of mixing of the mixture components.

Experimental studies of a twin-shaft mixer (Fig. 6), carried out at peripheral speeds from 1 to 2.1 m/s, show that minimum consumption electricity corresponds to the peripheral speed V p =1.31...1.45 m/s. When using the equality of peripheral speeds, at which the peripheral speed of the extreme points of the blades 10 for the prototype mixer (Figs. 6 and 7) with kinematic similarity is assumed to be equal to 1.4 m/s, the rotational speed of the blade shafts 4 and 5 of the prototype mixers with a capacity of 2, 5, 10 and 20 t/h are 50, 37, 29 and 23 rpm.

The blades 10, rotating with a variable swing radius, impart a variable peripheral speed of movement of the mixture components. The variable swing radius (the minimum swing radius of the blades is at the bottom point and the maximum after 90° in the direction of rotation) is created due to the movement of rollers 13 along the surface of the cams 9 when the blades 10 rotate. At the same time, they form a dust-like mixture based on mechanical fluidization, which combination with a cross countercurrent created by the arrangement of even blades on the shafts 4 and 5 in a helical spiral through 120° with the right direction of the spiral, and odd blades with the left, creates the effect of mechanical fluidization of the mixture into which it is convenient to introduce finely dispersed liquid components (Fig. 8 and 9). If necessary, liquid and viscous components are supplied from spray nozzles 15 located in the end walls 2 and 3 of the upper part of the mixing bath 1.

Thus, a cause-and-effect relationship was identified between the variable radius of the blades and the rotation speed of the blade shafts 4 and 5 of the mixer, ensuring minimal electrical energy consumption and obtaining a homogeneous mixture in a short period of time.

Then the drive 7 is turned on, which opens the doors of the discharge pipe 17, and the finished mixture is unloaded from the mixing bath 1.

The test results of an experimental sample of a twin-shaft mixer showed that it ensures homogeneity of the mixture at a mixing time of 30 s (Fig. 6).

Thus, the use of the invention will allow:

Optimize the process of mixing feedstocks that differ in their granulometric composition and physical and mechanical properties by maintaining a variable swing radius of the blades 10 and imparting a variable peripheral speed of movement of the mixture components;

Expand the scope of application due to the formation of a dust-like mixture, due to the cross countercurrent created due to the arrangement of even blades on the shafts of 4 and 5 in a helical spiral through 120° with the right direction of the spiral, and odd blades with the left;

Obtain homogeneous multicomponent mixtures of high quality thanks to the effect of mechanical fluidization and uniform introduction of liquid and viscous components into the mixture bulk materials.

A two-shaft mixer, including a mixing bath, two shafts with blades, a drive, characterized in that in order to increase the efficiency of mixing and reduce the duration of the mixing process, the blades mounted on the shafts are rotated 45º relative to their axis, and on the first shaft the even blades are arranged in a helical spiral through 120º with the right direction of the spiral, and odd blades - with the left, on the second shaft even and odd blades are also located in similar helical spirals with left and right directions, inside each hollow blade shaft a fixed axis is coaxially installed, on which with a pitch equal to the pitch of the location blades on the blade shaft, cams are installed, with the outer surface of which rollers interact, installed at the ends of the blade struts, and springs are put on the struts located between the inner diameter of the blade shaft and the rollers, the upper part of the mixing bath body is made along a complex line corresponding to the trajectory of movement blades, determined by the outer surface of the cams, the upper edge of the blade, in contact with the inner surface of the mixing bath, is made of elastic material, nozzles for supplying liquid and viscous components are installed in the end walls of the upper part of the mixing bath body.

Similar patents:

The kneading device (2) has at least two shafts (12, 14) on which the tools (18, 22) located in the kneading chamber (6) are fixed. At least one of the tools (18, 22) is designed to transport the dough from the loading area (10) in the feeding direction (20) to the unloading hole (8).

The invention relates to agriculture, in particular to devices for preparing feed on livestock farms and complexes. The device for mixing dry food and dry additives consists of a hopper for dry food, in which an unloading auger is installed, made in the form of a spiral of circular cross-section; in the unloading area, the unloading auger is made in the form of U-shaped blades of circular cross-section, made of a rod with a diameter of 4...10 mm and rotated relative to the axis of rotation at an angle α=5...15° along the spiral turns in the hopper, while under the U-shaped blades of circular cross-section there is a mesh made in the form of a plate with rectangular punch holes with a width across the auger shaft of 15...30 mm and 30...70 mm long with 2...4 mm jumpers, parallel to the dry food hopper there is a multi-component dry additive dosing hopper, which has 6...20 paddle drums with flat radial blades in two to seven sections on a common shaft.

The invention relates to devices for mixing materials that have poor flowability and differ in density, for example, for mixing recipe components of animal and plant origin, as well as products of microbial synthesis, and can be used for preparing feed in agriculture.

The present invention relates to a collection device that collects powdered addition agent ejected from a pressure plasticizer closed type for plasticizing a high-viscosity material to be plasticized, such as rubber, plastic and ceramic, and a method for collecting powdered addition agent using a trapping device.

The invention relates to the chemical industry and can be used for processing organic raw materials. The installation includes a feedstock supply system (1), an anaerobic bioreactor (2), a biomass heater, a biogas removal system (3), a biomass removal system (7), and a process control system (6).

The invention relates to a mixer for preparing dental material and can be used in medicine. The mixer (10) for preparing dental material contains a mixing barrel (17) and a mixing rotor (16), inlet pipes (13, 14) of the mixer and an outlet pipe (15).

The invention relates to the field of producing spherical powders (SPP) for small arms. The method for producing spherical powder includes mixing the components in a reactor, preparing powder varnish in ethyl acetate, dispersing in the presence of glue and distilling off the solvent, while dispersing the powder varnish is carried out in a reactor with a volume of 6.5 m3 using paddle mixers with a variable inclination angle installed in the lower cantilever part of the shaft in 3-4 rows at an angle of 90° relative to the previous blade.

The invention relates to the processing of man-made materials and can be used in various industries: chemical, energy, fuel, as well as in the building materials industry for the preparation of composite mixtures with finely ground fibrous materials. The technological module for mixing technogenic fibrous materials consists of 1 vertical and 7 horizontal mixers with blades installed in series. The blades of the vertical mixer 4 are made of double-thrust screws, in the form of helical surfaces with unidirectional entry in the direction of material unloading. The blades 11, 13 of the horizontal mixer in the loading and unloading parts are made of single-thread screws unidirectional in the direction of unloading the material. Oppositely directed double-threaded helical blades 12 are installed between them. The horizontal mixer 7 contains a block for mechanical preliminary compaction of the mixture, represented by outer and inner cones, made of two-cones. The method of mixing technogenic fibrous materials includes mixing with an organic binder, steam humidification and mechanical compaction of the mixture. Mixing is carried out in two stages. At the first stage, turbulent-gyrational mixing occurs. At the second stage, recirculation mixing with steam humidification occurs. The invention provides mixing of technogenic fibrous materials with various physical and mechanical characteristics and improving the quality of the mixture by stage-by-stage high-speed mixing of the mixture with the organization of internal recycle at each stage of their mixing and a consistent increase in its density through mechanical preliminary compaction. 2 n.p. f-ly, 4 ill.

The invention relates to the field of mechanical engineering, where the starting components are mixed into a homogeneous mass, and can be used in agriculture and other industries. In a twin-shaft mixer, the blades are included in sets of assemblies that are mounted on each of four sides along horizontal square shafts along the length of the mixer and have round ends mounted in cylindrical housings with sealed ball bearings. At the same time, at the upper end of each vertical end, a blade is fixed in the slots, which is made in the form of radial plates with a thickness of at least 10 mm, a width of no more than 80 mm, and the lower end of each shank is made in the form of a worm with milled involute teeth, which provide the ability to rotate blades in vertical plane at 30°, 45° and 60°, according to the results of the bulk density of bulk materials, respectively 0.30, 0.55 and 0.75 t/m3, and the rotation of the horizontal round drive shafts for turning the blades and the square pipe shafts of the mixer is carried out from electric motors. Mixing homogeneity of at least 98% is achieved. The invention improves the reliability of sets of assembly units and reduces the metal and energy intensity of the entire process by more than 25% and 35%, respectively. 2 ill.

The invention relates to equipment for mixing bulk products and can be used in the feed industry, agricultural enterprises and other industries. A two-shaft mixer contains a mixing bath, two shafts with blades, a drive, while the blades installed on the shafts are rotated 45º relative to their axis, and on the first shaft the even blades are arranged in a helical spiral through 120º with the right direction of the spiral, and the odd blades - with the left one, on the second shaft, even and odd blades are also located in similar helical spirals with left and right directions; inside each hollow blade shaft, a fixed axis is coaxially installed, on which cams are installed with a pitch equal to the pitch of the blades on the blade shaft, with the outer surface of which they interact rollers installed at the ends of the blade struts, and springs are put on the struts located between the inner diameter of the blade shaft and the rollers, the upper part of the mixing bath body is made along a complex line corresponding to the path of movement of the blades, determined by the outer surface of the cams, the upper edge of the blade in contact with The inner surface of the mixing bath is made of elastic material; nozzles for supplying liquid and viscous components are installed in the end walls of the upper part of the mixing bath body. The technical result of the invention is to increase mixing efficiency and reduce specific energy costs while achieving the best mixing uniformity through the implementation of a progressive mixing method based on mechanical fluidization in combination with cross-counterflow, as well as reducing the duration of the mixing process. 9 ill.

Details Created 03/05/2012 22:28 Updated 08/07/2012 16:52 Author: Admin

For mixing clay during semi-dry and plastic molding of ceramic products, as well as for preparing the charge in glass, silicate and other industries, single-shaft and twin-shaft paddle mixers of continuous and cyclic action are widely used.

Mixers of this group are used both for preparing a charge from several components, and for preparing a homogeneous mass in dry form or with moisture. Humidification can be done with water or low pressure steam.

In the latter case, a higher quality of products is achieved, since the steam heats the mass and then, condensing, moisturizes it. The main parameter of paddle mixers is their performance. The industry produces mixers with a capacity (for clay): 3, 5, 7, 18 and 35 m 3 /h with blade diameters of 350, 600 and 750 mm, respectively.

The picture shows twin shaft paddle mixer continuous action. It consists of a trough-shaped body 2, closed by a lid 1, in which horizontal shafts 3 are placed, with blades 5 installed on them. The shafts are driven towards each other by an engine 10, through a friction clutch 9, a gearbox 8 and a gear pair 7.

The blades are installed at angles at which the optimal ratio of circumferential and axial velocities of particle movement is achieved, which ensures the required time for the components to pass from window 6 to unloading hatch 15 and, consequently, the quality of mixing.

To moisten the mixture, steam enters through the gaps in the scaly bottom 14, which is supplied through pipe 13 through distributors 12. To reduce heat loss, the lower part of the body is closed with a casing 11 filled with mineral wool. The mass can also be moistened with water supplied through collector 4.

To ensure high-quality mixing, use twin shaft counter flow mixers. Structurally, they are identical to the mixer shown above, but the angles of installation of the blades on the shafts are opposite in sign. This arrangement of blades creates certain counter flows of particles, when general direction movement of the mixture towards the unloading window, since the angular velocity of shaft 1 is greater than the angular velocity of shaft 2.

The installation angles of the blades and the ratio of the angular velocities of the shafts for specific conditions are determined experimentally. For preliminary mixing of dry mixtures, single-shaft paddle mixers are used. Most often, they perform two functions: mix and move materials, for example, from bins to other units. Structurally, such mixers are similar to those discussed above, but have one blade shaft.

For particularly thorough mixing (difficult to homogenize mixtures), cyclic mixers are used, for example, twin-shaft mixers with Z-shaped blades. Depending on the required homogeneity, the mixing time in such mixers can be 20-30 minutes.

Continuous twin-shaft paddle mixers can also operate in cyclic mode if they are equipped with a shutter and the blade installation pattern is changed.

A small twin-shaft paddle mixer visually (video):

Basis for calculating the performance of cyclic mixers:

where V is the volume of the mixer
z - number of cycles per hour.

General performance of continuous mixers:

P = 3600·F·v os,

where F is the cross-sectional area of ​​the material flow in the mixer, m2;
v oc - axial speed of material movement, m/s.

With some assumption, the working parts of a paddle mixer can be considered as an auger with an intermittent screw. The axial speed of material movement (m/s) depends on the peripheral speed of the blades, their shape and installation pattern.

WTS twin-shaft batch mixers produce high-quality mixtures in the shortest possible time with the lowest possible energy consumption. The product is processed in the most delicate way without any damage to the product during the mixing process.

Description

WTS Twin Shaft Batch Mixers are mixers with two parallel drums and two shafts that rotate in opposite directions and are equipped with blades that ensure homogeneity of the mixture regardless of the particle size and bulk density of the products being mixed. High quality of the mixture is achieved due to the efficiency of multidirectional rotation of the blades overlapping each other.

This design ensures gentle mixing in a short time, as well as low energy consumption.

During the intensive mixing process, even fragile product particles are not destroyed.

The mixer can be started under load.

Function

Thanks to special design and the arrangement of mixing blades on both shafts, the WTS batch mixer allows the creation of a fluidized bed.

This is made possible by two different mixing technologies: turbulent motion and displacement. In combination with the low load, the product mass moves freely. In a fluidized bed, the optimal distribution of powders and granular materials occurs in a very short time. Therefore, the WTS twin-shaft paddle mixer provides high level homogeneity and high mixing speed.

The mixing process on the WTS twin-shaft batch mixer is particularly efficient due to the multi-directional rotation of the overlapping blades. This ensures homogeneity of the mixture regardless of the particle size and bulk density of the mixed products. This design ensures gentle mixing in a short time, as well as low energy consumption. WTS twin-shaft mixers are used for mixing dry bulk materials (powders, granules, short-fiber products), dry bulk materials with liquids (humidification, granulation), as well as low-viscosity pastes.

Peculiarities

  • Productivity: from 48 to 5000 liters per batch
  • Coefficient of variation: less than 3%
  • Mixing ratio: 1/100,000
  • End bearings with different types air/gas purged shaft seals
  • Large double bomb bay
  • Mixing chamber made of carbon steel or 304L stainless steel

Advantages

  • Excellent mix reproducibility
  • Minimum possible losses (0–0.5% volume)
  • Minimum unloading time thanks to double bomb bay
  • Durable equipment
  • Easy cleaning and access to all internal parts of the faucet
  • Combination of production experience and testing equipment

Options

  • Mixer chamber and shaft made of 316L stainless steel
  • Painting for use in the food industry
  • Rotating rod for spraying liquid
  • Liquid supply equipment
  • Mixing chamber with heating/cooling jacket
  • Removable paddles

Twin-shaft paddle batch mixers WTS allow you to obtain high-quality mixtures in the shortest possible time with the lowest possible energy consumption. The product is processed in the most delicate way without any damage to the product during the mixing process.

WTS Twin Shaft Paddle Mixers are batch mixers with two parallel drums and two shafts that rotate in opposite directions and are equipped with paddles that ensure homogeneity of the mixture regardless of the particle size and bulk density of the products being mixed. High quality of the mixture is achieved due to the efficiency of multidirectional rotation of the blades overlapping each other.

This design of the WTS mixer ensures gentle mixing in a short time, as well as low energy consumption.

During the intensive mixing process, even fragile product particles are not destroyed.

The WTS twin-shaft mixer can be started under load.

Function of WTS twin shaft paddle mixer

Thanks to the special design and arrangement of mixing paddles on both shafts, the WTS batch paddle mixer allows the creation of a fluidized bed.

This is made possible by two different mixing technologies: turbulent motion and displacement. In combination with the low load, the product mass moves freely. In a fluidized bed, the optimal distribution of powders and granular materials occurs in a very short time. Therefore, the WTS twin-shaft paddle mixer ensures a high level of homogeneity and high mixing speed.

The mixing process on the WTS twin-shaft batch batch mixer is particularly efficient due to the multi-directional rotation of the overlapping blades. This ensures homogeneity of the mixture regardless of the particle size and bulk density of the mixed products. This design ensures gentle mixing in a short time, as well as low energy consumption. WTS twin-shaft mixers are used for mixing dry bulk materials (powders, granules, short-fiber products), dry bulk materials with liquids (humidification, granulation), as well as low-viscosity pastes.

Features of WTS twin-shaft mixers

  • Productivity: from 48 to 5000 liters per batch;
  • Coefficient of variation: less than 3%;
  • Mixing ratio: 1/100,000;
  • End bearings with different types of air/gas purged shaft seals;
  • Large double bomb bay;
  • Mixing chamber made of carbon steel or 304L stainless steel.

Advantages of WTS paddle mixers

  • Excellent reproducibility of mixtures;
  • Minimum possible losses (0–0.5% of volume);
  • Minimum unloading time thanks to double bomb bay;
  • Durable equipment;
  • Easy cleaning and access to all internal parts of the mixer;
  • Combination of production experience and testing equipment.

Options for WTS mixers

  • Mixer chamber and shaft made of 316L stainless steel;
  • Painting for use in the food industry;
  • Rotating rod for spraying liquid;
  • Liquid supply equipment;
  • Mixing chamber with heating/cooling casing;
  • Removable blades.

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