SU1478020A1 - Method and apparatus for drying ,particularly, ceramic articles - Google Patents

Abstract

The invention relates to the production of building materials, in particular, to the technology of producing ceramic products, specifically to the technique of clay brick drying. The invention allows to increase the productivity, efficiency and quality of products. Drying of ceramic products is carried out in the tunnel chamber 1, equipped with a mechanism for continuous transportation of products along the chamber and having 8 microwave energy inputs, and a gaseous coolant under the action of which the ceramic products are dried, while in the first drying period the microwave energy is accompanied by the supply of wet coolant, in the second period - with the supply of dry coolant. Microwave energy is distributed according to a parabolic law, and its share of the total amount of heat-transfer agent is 80-95%. 2 sec. and 7 hp f-ly, 1 tab., 6 ill.

Description

The invention relates to the production of building materials, in particular, to the technology of producing ceramic products, such as clay bricks, and specifically to the technique of drying bricks.

The purpose of the invention is to increase the productivity, efficiency and quality of products.

Figure 1 shows the device, a general view; figure 2 - section aa in figure 1; on fig.Z - section BB in figure 1; figure 4 is a section bb In figure 1; figure 5 - section GGD fig.Z; figure 6 - section dd in fig. one .

The device contains a tunnel chamber 1 with adjacent waveguides 2 preventing the leakage of microwave energy into the surrounding space, with loading 3 and discharge 4 windows, placed along the length of the tunnel chamber 1 with conveyor belt 5 with roller support 6 of transport tape 7, inputs 8 microwave energy, the source 9 of the gaseous coolant, including, for example, the blower 10 and the heater 11, with the supply of coolant into the tunnel chamber 1 by the path 12, is made branched. In this case, the branch 13 is dispersed attached to the output part 14 of the tunnel chamber 1 by means of a section 15 connected to it with variable cross-section windows 16 with the latter increasing to the discharge window 4 beginning, for example, from the transverse axis of symmetry of the tunnel chamber 1. Opposite section 15 is installed a section 17 for receiving drying products with a nozzle 18 for transporting drying products to the outside and a pipe 19 with an adjustable cross section connected to the outgoing waveguide 2 with a loading window 3 for recycling the waste go coolant.

Another branch 20 of the path 12 is provided with a pipe 21 with an adjustable cross section for supplying steam to the branch 20 and is also connected to the outgoing waveguide 2 with a loading window 3, and on the side of the latter a blower 22 is installed which is tangentially connected to the outbound waveguide 2 at an acute angle to the longitudinal axis of the tunnel chamber 1.

Roller supports 6 of the conveyor belt 7 are provided with a plate 24 diametrically located in their body.

as a hexagon.

The internal cavity 25 of the beyond waveguide 2 with a loading window 3 is provided with ribs 26 along the waveguide forming part.

In the section 15 for bringing coolant into the tunnel chamber 1 in the transverse direction and in section 17 for draining drying products 1 out of the tunnel chamber 1, ribs 27 are made parallel with high absorbing microwave energy material, for example, from ferrite.

In addition, a device 28, such as a heat pipe, is installed in section 17 for discharging the drying products, for utilizing unused heat generated by microwave electromagnetic waves, and also used as a ballast load, connected to section 15 for entering the tunnel chamber 1. Herewith ribs 27 and device 28 are structurally aligned. The same ribs 27 are installed in the pressure pipe 23.

The device works as follows.

In the tunnel chamber 1 with adjacent waveguides 2 on both sides, preventing the leakage of microwave energy into the surrounding space, through the loading window 3 with conveyor 5 with roller support 6

transport tape 7, made of radio transparent material, serves wet clay brick, which continuously moves in the tunnel chamber 1 from the loading window 3 to

unloading window 4. Using

inputs 8 of the microwave energy, the power of which along the length of the tunnel chamber 1 is formed according to a parabolic law, for example, at the beginning and at the end of the chamber

less powerful sources of microwave energy are installed, and on the transverse axis of symmetry of the tunnel chamber 1 - maximum power, the bricks are dried. At the same time, intensive evaporation of moisture occurs from the entire volume of the brick.

To prevent cracking and distorting the geometry of the brick from the beginning of the impact of the microwave floor with

a lower energy potential before exposure to a microwave floor with a maximum energy potential (from the beginning of the tunnel chamber to its transverse axis of symmetry) creates a high relative humidity, which ensures the plasticity of the upper layers of the brick. Moisture in the form of a pair (geyser effect) as well as free moisture due to the piston effect. The plasticity of the upper layers prevents the development of a volume-stress state in a brick. The described mechanism for the transfer of moisture from the inner layers of a brick to its upper layers contributes to the formation of high porosity in the latter.

In the first period, from the beginning of drying to the maximum value of microwave energy, 70-90% of moisture is removed from the brick due to its removal from the inner layers of the brick. The remaining moisture is removed from the upper layers and its residue from the inner layers during the second drying period — from the maximum value of the microwave energy to the discharge port 4 (the output part 14 of the tunnel chamber 1, where a high temperature and low relative humidity are created coolant (blowers 10 and heater 11), the heat carrier distribution is fed in the transverse movement of the product direction of the branch 13 of the tract 12 in the output part 14 of the tunnel chamber 1 through the section attached to it and 15 through windows 16. Drying products through section 17 and pipe 18 are discharged to the outside, part of them through pipe 19 with an adjustable cross section is recycled - used to form a moist environment in the first drying period.

To form from the loading window 3 to the transverse axis of symmetry of the medium with high relative humidity and to induce the movement of the drying products along the tunnel chamber 1 to its outlet part 14, the device is also equipped with a branch 20 of the path 12 with a pipe 21 with an adjustable cross section for supplying steam to the branch 20 and blower 22 with pressure pipe 23. The air blown by the blower 22 in the pressure pipe

Jq

20 25 30 0 d

P

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five

de 23 is mixed with the coolant supplied by pipelines 19 and 21 respectively. The tangential connection of said pipelines to the pressure pipe 23, as well as tangential and at 90 ° relative to the longitudinal axis of the tunnel chamber 1, connects the pressure pipe 23 to the limiting waveguide 2 with a loading window 3 and the implementation of the inner surface of the limiting waveguide 2 with the ribs 26 along the waveguide forming contributes to the effective mixing of the air drawn in by the blower 22, recirculated, mainly a heat transfer fluid and steam economical pri- gotovleniyu in the first period of drying devices required therein relative humidity and ambient temperature, whereby most fully utilized device resources.

The duration of the drying process is set depending on the speed of transporting the products or the length of the tunnel chamber.

Uniform distribution of energy across the width of the conveyor belt, increasing the concentration of the electromagnetic field in the brick body, stable preservation of the floor structure, and as a result, more efficient heat treatment of the brick is achieved by rotating metal elements (plates 24) structurally combined with roller bearings 6 element combined two functions) and placed from each other at a distance equal to the wavelength equal to the wavelength.

Moreover, this effect is further enhanced in the zone of action, the maximum power of the microwave source (at the transverse axis of symmetry of the tunnel chamber) by placing the rotating plates 24 at a distance from one another equal to half the wavelength.

Utilization of unabsorbed microwave microwave energy during the drying process or in case of violation of the brick supply mode is carried out in parallel with ribs 27 placed from sections absorbing microwave energy and placed in sections 15 and I7 and the discharge pipe 23. - energy between sections 15 and 17

(heat extraction of section 17 and its supply to section 15) is carried out using an apparatus 28, for example a heat pipe, together with fins 27.

For example, a single clay brick is dried by the size of plastic pressing using the proposed device. The design of the device allows increasing the proportion of gaseous coolant or microwave energy, changing the power and distribution pattern of the latter over the length of the tunnel chamber, varying the technological parameters of the drying process (temperature and the relative humidity of the environment in the tunnel chamber, the flow rate and flow direction of the coolant into it, the drying time in the range of 5-20 minutes due to the speed of the conveyor belt and the length of the tunnel chamber). The initial conditions of sugaki are as follows: the brick is subjected to drying with a complex coolant (heated air in the microwave electromagnetic field). In this case, the proportion of microwave energy in the energy supply of the succule process is 90% and its value from the beginning to the end of drying is formed according to a parabolic law, i.e. at the beginning and at the end of the tunnel chamber the microwave energy is less than in its middle part (in the transverse axis of symmetry of the tunnel chamber) -.

From the side of the boot window. along the tunnel chamber to its transverse axis of symmetry serves coolant with a temperature of 25 C and relative humidity of 95%. The flow rate of this heat carrier is constant, and its speed from the loading window to the transverse axis of symmetry of the tunnel chamber is 0.2 m / s. After the transverse axis of symmetry of the tunnel chamber, i.e. After the maximum microwave energy heated to 60 ° C heat carrier (air) is fed in the transverse direction (perpendicular to the longitudinal axis of the tunnel chamber), the relative humidity from the maximum microwave power (from the transverse axis of symmetry of the tunnel chamber) to the end of the tunnel chamber decreases by exponent: 95 ,. 60, 40, 30, 20, 15, 13, 16, 10, 7 and 5%. The power supply of the drying process is provided780206

They supply 90% microwave energy and 10% coolant.

The results of testing the characteristics of the proposed method are given in the table (the values of the average values).

The proposed method provides a significant increase in productivity at comparable costs. At the same time, the structural and mechanical properties of the dried brick are increased by increasing the strength properties, the number of scrap is significantly reduced by reducing the fracture and distortion of the brick geometry, and the production area occupied by the device is reduced.

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Claims (9)

1. Method of drying mainly ceramic products, including removal of moisture by the gaseous coolant and processing them with a microwave-electromagnetic field, characterized in that, in order to increase productivity, efficiency and product quality, the proportion of microwave energy is 80-95% of the total amount of coolant, while its intensity from the onset of sugaki change according to a parabolic law, and the gaseous coolant from the beginning of drying until the maximum value of microwave electromagnetic iqjia is supplied with relative humidity 75-И5Ь% and a temperature of 1545 ° С without an increase in the coolant flow rate, after which the coolant is fed in the direction transverse to the movement of products and creates a positive temperature gradient, while the relative humidity decreases ayut exponentially. 2. A device for drying mainly ceramic products, containing a tunnel chamber with adjacent waveguides adjoining it on both sides, loading and unloading windows, a conveyor belt along the length of the chamber with roller carriers of the conveyor belt, a microwave energy source made along the length of the tunnel chamber Communication windows and a blower, characterized in that the output part of the tunnel chamber is provided with one side of the gas distribution section with a source of gaseous coolant, opposite to which there is a recirculation section of the drying products with a pipeline, while the gas distribution section on the side of the tunnel chamber is made with variable section windows with the latter increasing in the direction of movement of the product, and the source of gaseous coolant and recirculating pipeline are connected to the pressure pipe of the blower, which is connected to the transverse waveguide tangentially. 3. The device according to claim 2, characterized in that the roller supports of the conveyor belt are provided with a diagonally arranged in their body plate in the form of a hexagon. 4. The device according to claim 2, characterized in that the internal cavity of the outlying waveguide at the entrance of the tunnel chamber is provided with ribs along the generatrix. 5. The device according to claim 2, of which is that the gas distribution section and the section for discharging the drying products are provided with ribs installed perpendicular to the longitudinal axis of the tunnel chamber, and the section for discharging the drying products is additionally equipped with heat recovery a device, such as a heat pipe connected to the gas distribution section. 6. The device according to claim 2, о.т l and that the pressure channel of the blower, conjugated with the outgoing waveguide from the side of the loading window, is made cone-shaped with the base in the form of an ellipse, and the larger diameter of the ellipse is combined with the forming of the beyond waveguide . 7. The device according to claim 2, about tl and 5 such that the pipelines for supplying the main coolant and recirculation are tangentially connected to the pressure path of the blower installed from the side 0 loading windows, and are located mutually opposite with an offset along the diameter of the section of the tract. 8. The device according to claim 2, about tl and - 5 that the pressure the path of the blower installed on the side of the loading window is provided with a nozzle located at the base of the cone-shaped pressure path of the air blower in the form of parallel ribs. 9. The device according to claim 2, which means that the edges are made of ferrite.  The share of microwave energy for energy supply of the process of combined drying of clay bricks (microwave energy and coolant gas at a relative humidity of 75- 95%, temperature 15-45 ° С in the 1st half of the tunnel chamber and 60-150 ° С in the 11th half of it),% 75 80 85 90 95 100 18 21 20 22 20 17 50 63 60 60 61 48 1300 1290 1294 1290 1290 1300 f The relative humidity of the media in the 1st half of the device from the side of the loading window is 80–95% microwave frequency fraction, the medium temperature is 15–45 ° C and 60 in the 11th half of devices a, J5 70 75 85 90 95 100 Medium temperature in the 1st half of the device, ° С, with a share of microwave energy of 80-95%, a relative humidity of this medium of 75-95% and a medium temperature in the half of the installation 60-1500 ° С 5 Compiled by L. Matsuk Editor I. Derbak Tehred M. Khodanych Order 2351/39 Circulation 533 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Table continuation : g gtgpe: 17 23 20 22 21 18 48 63 60 59 61 51 1300 1287 1291 1290 1290 1300 &BUT. & Phag.b Proofreader I. Muska Subscription