RU2526396C1 - Method for bakery goods baking in moulds moving rectilinearly on conveyer inside tunnel oven - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: according to the method, the moulds are relocated rectilinearly on the conveyer inside the tunnel oven tunnel covered from above with thermoinsulation. The goods are relocated on the leading branch of the conveyer; the tunnel, goods, branch and moulds are heated with directionally-focused radiation maintaining the preset temperature automatically. The moulds are heated with this radiation from below and from the sides. The goods are heated from above with this radiation reflected from the inner surface of the tunnel that is designed in the form of a trough arched along the circumference arc, curved upwards and made of aluminium alloy. The mould-transporting conveyer element is designed in the form of a meshed transporter with steel mesh of stainless steel containing chromium with mesh cells sized no more than 10×10 mm; the mesh leading branch is placed horizontally along the tunnel at the level of its opened free borders with identical gaps between the mesh and the tunnel borders to the left and to the right. The cross section of the gaps across the width of the tunnel exceeds by 10 mm the diameter of the bulbs of radiators represented by identical infrared reflector lamps IKZ-500 positioned vertically with bulbs upwards along the tunnel under the mesh leading branch in uniform rows with uniform gaps in the row at the same level so that at least two rows of lamps are positioned under the mesh. In the gaps between the mesh and the tunnel borders, at least with one row of lamps, the minimum gap between the mesh and the lamp bulbs is maintained. The tunnel inner surface is mirror-polished. The lamps are divided, along the tunnel length, in three groups with identical electric power.

EFFECT: invention usage will allow to enhance the quality of bakery goods baking.

8 dwg

Description

The present invention relates to food production technology and can be used for continuous and / or periodic heating, or baking, or drying, or roasting, or roasting, or baking food semi-finished products in forms, i.e. for their heat treatment. Including - until the complete preparation of the finished food product from them. The method can be used for preparing steaks, steaks, meatballs, meatballs from semi-finished products, for baking breads, rolls, cookies and gingerbread cookies, for heating first and second courses in containers, for drying crackers, cereals, herbs, berries, mushrooms, etc. .

The method can be used for continuous heat treatment of building, engineering, instrument-making, biological, polymer and chemical semi-finished products and thermoplastic materials in molds.

1. The prior art

A known method of heating piece food semi-finished products on a conveyor, in which the conveyor is placed inside the lined body (inside the hearth) of the tunnel furnace, which creates a loading window for loading piece semi-finished products on the conveyor. Inside the casing (hearth), gaseous fuel is continuously burned, maintaining a predetermined high temperature inside the casing (hearth), while simultaneously removing the products of fuel combustion (through smoke tubes). In the process of heating semi-finished products, overheated steam from the steam generator is periodically fed from the top of the casing (hearth) to moisten semi-finished products that lose moisture [1, 2].

The disadvantages of this method are the complexity of the operations, huge material consumption, high energy consumption of operations, environmental pollution and fuel combustion products and its thermal pollution. Similar disadvantages have similar methods described in the sources [3-12]. Even more complex is the method according to the application RU [13], in which, for heating, the operation of heating with electric heaters (heating elements) is additionally used (for the operation of burning fuel).

Similar methods for heating semi-finished products are known, in which the high temperature inside the body (inside the hearth) of the tunnel kiln is created and supported by electric heaters (TENs) [14-16]. These methods do not pollute the environment with fuel combustion products and exclude thermal pollution of the environment. Their disadvantages are the complexity of the operations, the huge material consumption and high energy consumption of operations due to the small outer surface of the heating elements and the long heating time of the air (due to its low thermal conductivity) inside the body (hearth) of the furnace.

A known method of heating piece technical products in a tunnel kiln moving rectilinearly as part of a conveyor is described in [17, 18], in which the conveyor is made of separate interlocked bogies moving rectilinearly along a lined furnace body (tunnel).

The carts are moved inside the tunnel along the rails, and the air inside it is heated by electric heaters (heating elements) or radiating tubes, which are motionlessly placed in rows both above the heated products and under the carts.

The most significant disadvantages of this method are the complexity of the operations, the huge material consumption and high energy intensity of operations.

The complexity of the method lies in the need to create a lined body of a tunnel (or any other furnace from known methods of heating piece goods) furnaces, create a conveyor moving inside this tunnel at high temperatures, create carts, lay rails for them, create a foundation for rails, provide lubrication of the wheels of carts operating at high temperatures, as well as the need to create and maintain a steam generator and steam line for supplying steam inside the tunnel of the furnace for humidification etc. The same drawback is inherent for cradle conveyors in analogues [1, 2].

The huge material consumption is due to the massiveness of the lined shell-tunnel of the furnace, conveyor elements and steam humidification elements.

The high energy intensity of operations is due to the large consumption of electric energy for heating and the drive, given the massiveness of the moving parts of the conveyor and the large energy losses due to friction in these moving parts (in links).

In fact, it is necessary to heat only semi-finished products, while in the prototype only a small part of the thermal (primary-electric) energy of electric heaters is spent on heating products.

Electric heaters pos.2 (figure 1) in the analogue [18] are placed not over products with a minimum clearance with them, but in the upper part of the internal cavity of the tunnel. These heaters (heating elements or radiating tubes) have the property that they heat the air surrounding them, creating its convection, when the air comes into contact with the heated surface of the heater, and the heated air rises. The placement of electric heaters pos.2 (in this analog) leads to air heating by convection only under the ceiling of the furnace body (hearth). These heaters (heating elements or radiating tubes) have the property that they create thermal (electromagnetic) radiation. But TENs or radiating tubes, due to the low temperature of the outer surface (700–900 ° C), generate radiation with a rather large wavelength ≈3.2 μm and a rather small specific radiation power ≈5 * 10 ⁵ W / cm ² [19, p.29, fig. 2-5]. Whereas the well-known sources of directional infrared radiation (infrared mirror light bulbs, with a mirror reflector inside the bulb that creates the directional radiation) of the type IKZ (infrared mirror) [20], with a nominal spiral temperature of 2350 K create a specific power of directed infrared radiation ≈2 * 10 ⁷ W / cm ² [19, p.29, fig. 2-5], i.e. ≈ 40 times more powerful at the same energy costs. Electric heaters (heating elements or radiating tubes) create uniformly dispersed thermal (partially infrared) radiation from a cylindrical surface. It partially heats the ceiling of the body (hearth) of the furnace, partially surrounding the air and only partially the product (semi-finished product).

It is also known that the energy of directed electromagnetic radiation in the infrared spectrum is partially absorbed by the surface (heats the surface), partially reflected from the surface (scattered) and partially penetrates through the wall with the surface. It is known at the same time that chromium and iron absorb the energy of the IR spectrum best of metals, and the power of penetrating radiation decreases with increasing thickness of the irradiated wall [21].

Electric heaters pos. 3 (Fig. 1) in an analogue [18] are placed under massive trolleys and, like electric heaters 2) heat the surrounding air partially with convection and partially with radiation. Part of the radiation energy is spent on heating the air. Other parts of this energy are spent on heating the carts 4 from below and on heating a massive foundation (base) along with rails (with guides 6). Thus, only a tiny fraction of the electric power (thermal energy of electric heaters - heating elements or radiating tubes) is spent on heating the semi-finished products (products) themselves.

On the other hand, the large masses of the lined body, conveyor parts, cradles or trolleys, foundations (bases) create a greater inertia of the heating process. Heating of semi-finished products (products) can begin only after the air and carts have warmed up. To heat up everything that is not a semi-finished product, much more energy is consumed in time than is necessary to maintain the necessary temperatures of the semi-finished products.

Low reliability, durability and maintainability are also due to the fact that heating devices, moving friction elements of the conveyor (movable joints) and elements of the conveyor drive are located inside the tunnel furnace, i.e. in conditions of high temperatures and humidity. This causes accelerated wear, corrosion and the inability to replace the heaters when they fail without stopping the entire process of the tunnel furnace.

A known method of heating (including baking) of food piece semi-finished products moving rectilinearly on the conveyor [22].

In this heating method, the semi-finished products move rectilinearly on the conveyor and they are heated, moving together with the conveyor. At the same time, the semi-finished products are heated by infrared radiation directed at them from above perpendicular to the trajectory of their movement, placing the emitters of this radiation over the semi-finished products uniformly relative to them in length and width with a minimum gap between the radiators and with an adjustable gap between the radiators and semi-finished products. The conveyor is made in the form of an endless thin conveyor flat belt moving rectilinearly, a portion of which, together with the semi-finished products, is heated with the infrared radiation directed to the belt from below, perpendicular to the trajectory of its movement, placing emitters of this radiation under the belt uniformly along its length and width, with a minimum the gap between the emitters and with an adjustable gap between the emitters and the tape. In addition, the semi-finished products are additionally heated by the same radiation penetrating through the tape, and the power of the directed infrared radiation and its density near the semi-finished products are regulated.

This method allows to significantly reduce energy consumption for heating semi-finished products, to simplify the design of the device for its implementation, installation, commissioning, configuration and maintenance.

Its most significant drawback is the inability to use for baking bakery, confectionery, bagels (dryers) and gingerbread cookies. This method is implemented with the achievement of the ultimate goal (baking the finished product) only for thin-layer semi-finished products such as pancakes, pancakes or pancakes. This method has too limited functionality.

In fact ([22], FIGS. 1 and 2), considering the method (technology) of heating the semi-finished products 14 (FIG. 2) in the cross section of the conveyor belt 1A or 1B, it is seen that the radiation heating of the semi-finished products 14 is carried out mainly from above and , partially, from below. Below, in part, because the flux of directionally focused (reflector of ICZ lamps) radiation from the lower rows of 10 H lamps is almost completely absorbed and reflected by the material of a continuous conveyor belt 1A or 1B. Only 10% of the radiation energy penetrates through the material of the tape 1A (1B), heating the semi-finished products directly by radiation. Therefore, from below, the semi-finished products are heated mainly (90%) by the thermal conductivity of the surface of the tape heated by radiation, while from above, these semi-finished products are heated exclusively by radiation.

The difference between heat transfer by heat conduction and radiation is that in convection and heat conduction, the energy transfer is approximately proportional to the temperature difference in the first degree. In heat transfer by radiation, energy transfer is also proportional to the temperature difference, but absolute, and each of them is raised to the 4th or 5th degree [23]. From the above information, it is clear that for the same temperature effect (uniform heating) on the semi-finished products on the side of the heaters (emitters), it is necessary that the power of the lower emitters be at least 5 times that of the upper ones. However, the nominal power of emitters of the type of ICZ lamps known in world practice is: minimum - 175 W (IKZ-175), maximum - 500 W (IKZ-500) [20]. That is, if the upper emitters are IKZ-175 lamps, and the lower - IKZ-500 lamps, then the ratio of the power of the lower emitters to the upper ones will be only (500 / 175≈2.86). From this it follows that if IKZ-175 lamps are placed with the top emitters, then for each IKZ-175 lamp from above - from the bottom two IKZ-500 lamps are needed. However, lamps with different power have different bulb diameters (dimensions). For example, the diameter of the IKZ-175 flask is 113 mm, and the IKZ-500 is 137 mm [20]. Therefore, if, for example, there are 4 IKZ-175 lamps on top, their total size (length across the conveyor belt) will be 452 mm, and 8 IKZ-500 lamps on the bottom will be 1,096 mm, i.e. 2 times more. When the semi-finished products are arranged on a length of 450 mm (across the tape, on the length of the bulbs of 4 IKZ-175 lamps) above, only the middle 4 IKZ-500 lamps from below will emit onto the semi-finished products (heat them). When the semi-finished products are located on a length of 1000 mm (across the tape, on the length of the bulbs of 8 IKZ-500 lamps), from above, the semi-finished products will be heated only in the middle by 4 IKZ-175 lamps.

On the other hand, bakery and confectionery products having a length, width and height are baked in molds having a wall thickness, weight, length, width and height. For baking these products, it is necessary to heat the molds not only from below and above, but also from the sides. The above method does not allow the heating of the forms (or the semi-finished products themselves) from the sides (in the direction of radiation perpendicular to the direction of movement of the grid in its plane). Therefore, it is possible that thin and flat semi-finished products (for pancakes, pancakes and pancakes) will be baked (baked) until cooked. Thus, the baking of bakery products in molds by this method by known technical means is not feasible.

Also known is a method of heating food piece semi-finished products on a conveyor inside a tunnel oven [24], in which the tunnel of the furnace is made in the form of a thin-walled rectangular, sectional pipe. The length of this pipe is greater than the dimensions of the diameter. It is placed horizontally and motionlessly, and the conveyor is made in the form of an endless, thin and heat-resistant, flat conveyor belt with a drive. A rectilinearly moving section of the tape, together with the semi-finished products, is directed inside the pipe parallel to it with a small gap relative to its inner bottom surface and with uniform gaps relative to the inner side surfaces. At the same time, the semi-finished products are heated by the air surrounding them inside the pipe, heated by a conveyor belt inside the pipe and directed infrared radiation penetrating through the pipe wall at the same time. The surface of the pipe is heated from the outside, from the bottom and from the sides, along its length directed perpendicularly to infrared radiation, while simultaneously measuring the temperature inside the pipe and automatically maintaining it within specified limits, while the outer surface of the pipe is covered with a layer of heat-resistant thermal insulation from above.

This technical solution allows you to accumulate thermal energy and equalize the temperature inside the tunnel.

2. The closest technical solution (prototype) is a method for heating piece products in a tunnel kiln moving rectilinearly in a conveyor, described in [22, 24] (combined prototype).

In this baking method, bakery products in molds are moved rectilinearly on a conveyor inside a tunnel covered with heat insulation from the tunnel oven, and the products are moved on the leading branch of a moving conveyor to heat the tunnel, products, heating this branch and molds using directionally focused radiation in the near infrared region ( through NIKI).

The main objectives of the invention (in comparison with the prototype) is to obtain the following technical results:

1) reducing the cost of electric energy for heating;

2) a decrease in the material consumption of the structural elements of the method;

3) simplification of the implementation of the method of baking bakery products in molds moving rectilinearly on the conveyor;

4) a significant increase in reliability, durability and maintainability.

3. Reasons that hinder the receipt of technical results.

The most significant disadvantages of this method (prototype) are the high energy intensity of the operation of heating products in forms, excessive material consumption and the complexity of the operations.

3.1. The high energy intensity of operations is due to the high consumption of electric energy for heating the mass of the tunnel.

In the prototype, infrared radiation from IKZ type lamps mainly heats the tunnel body (bottom and sides) of the product, for example, in the molds and the leading branch of a flat ribbon are heated only by thermal radiation of the tunnel’s inner surface from the bottom and sides, the temperature of which is relatively lower (up to 723 K ) than the temperature of the lamp spirals (2350 ± 100 K). According to the Stefan-Boltzmann law [21], the radiation energy density (W / m ² ) is proportional to the absolute temperature (T) of the body to the 4th degree (T / 100) ⁴ . Therefore, the radiation density (723/100) ^{4 of the} inner surface of the tunnel will be equal to 7.23 ⁴ ≈2732 W / m ² (and for a lamp spiral 23.5 ⁴ ≈304 980 W / m ² ) is 111 times less than a lamp. Heating with tunnel lamps by a factor of 111 reduces the radiation density from the lamps, increasing the consumption of electrical energy for heating baked goods (to maintain a given temperature inside the tunnel).

In addition, a continuous conveyor belt in cross section is also an obstacle to radiation from the heated lower edge of the tunnel.

The increased energy consumption for heating is also due to the open ends of the tunnel. When the tunnel is heated, the air inside it heats up, its pressure increases and it continuously flows out of the tunnel, and instead, cold air continuously enters the tunnel from the space surrounding the tunnel. Such forced ventilation of the tunnel lowers the temperature inside it and requires an increase in the power (increase in supply voltage) of the emitters to maintain a given temperature inside the tunnel.

3.2. The excess material consumption is due to the massiveness of the tunnel, the wall of which in the cross section is solid, as well as the solid body of the conveyor belt.

3.3. The complexity of the implementation of the method lies in the complexity of placing the conveyor inside the tunnel, its installation, dismantling and repair. Installation of side heaters with shelves tilting left and right to replace damaged radiators is also difficult. Complex is the fact that the tunnel is made continuous in length. In this case, when the conveyor is forced to stop, it is not possible to get the baked goods from the inner cavity of the tunnel, given that the length of the tunnel is at least 2 meters.

An additional complexity of the implementation of the baking process is provided by a device for moistening baked products. In the prototype, a humidification device (and operation) are necessary for the following reasons. With the open ends of the tunnel (as shown above in Section 3.1) inside the tunnel, along it, during heating, a continuous flow of air occurs due to convection. This continuous flow takes away the vapor of moisture evaporating from the surface of the dough, and after the products exit the tunnel (after baking) they become overdried if they are not moistened additionally during the baking process.

Additionally, the following is known.

D1. Infrared mirror incandescent lamps of the type IKZ emit not just infrared radiation, but directionally focused radiation in the near infrared region (λ = 0.6-1.9 μm). The range λ = 0.6-0.75 μm refers to the range of visible light (Appendix 1) [20]. The directivity and focusing of radiation is carried out by a mirror reflector inside the lamp. The maximum rated electrical and radiation power from existing IKZ-175, IKZ-250 and IKZ-500 lamps is available for IKZ-500 (500 W) lamps. The bulb of this lamp and the reflector in the bulb have the appearance of a hemisphere, and the spiral is placed in the focus of the reflector (Appendix 2). Further in the text, this directionally focused radiation in the near infrared will be abbreviated as NIKI.

D 2. It is known that aluminum and aluminum alloys possess the maximum reflective properties in the NIKI spectrum. Chromium possesses high absorbing properties among metals, including in the composition of steels [25].

Known silicone heat-resistant (up to 650 ° C) paint "CERTA" black, manufactured by NPP "Spectrum" TU 2312-001-49248846-2000 rev. 1, 2, containing silicon and carbon [26]. Silicon and carbon absorb the NIKI energy to the maximum [21], while the metal surfaces coated with this paint heat up 25% more intensively without increasing the NIKI power [24, 27, 28].

4. Signs of the prototype, coinciding with the claimed invention.

A baking method in which bakery products in molds are moved rectilinearly on a conveyor inside a tunnel covered with heat insulation from a tunnel oven. Products are moved on the leading branch of a moving conveyor, heating the tunnel, products, branch and shapes by means of directionally focused radiation in the near infrared region, maintaining a predetermined temperature inside the tunnel automatically.

5. The objectives of the invention are the following technical results:

1) reducing the cost of electric energy for heating;

2) a decrease in the material consumption of the structural elements of the method;

3) simplification of the implementation of the method of baking bakery products in molds moving rectilinearly on the conveyor;

4) a significant increase in reliability, durability and maintainability.

6. These technical results in the inventive method of baking bakery products in molds that move rectilinearly on a conveyor inside a tunnel covered with heat insulation from the tunnel kiln, in which products are moved on the leading branch of a moving conveyor, heating the tunnel, products, branch and molds using directionally focused radiation in the near infrared region, maintaining a predetermined temperature inside the tunnel automatically, are achieved by the fact that the forms are heated by this radiation from below and from the sides, and the products are heated on top of this radiation, reflected from the inner surface of the tunnel, which is made in the form of a trough curved in an arc of a circle, curved upward, from an aluminum alloy, while the conveyor-transporting element is made in the form of a mesh conveyor with a stainless steel mesh containing chromium and dimensions cells of at least 10 × 10 mm, positioning the leading branch of the grid horizontally along the tunnel at the level of its open free edges with the same gaps between the grid and these edges of the tunnel left and right, and these gaps The width of the tunnel in the cross section is 10 mm greater than the diameter of the bulb of emitters, which use the same infrared reflector lamps IKZ-500, placing them vertically with the bulbs up along the tunnel under the leading branch of the grid in uniform rows with uniform gaps in a row at the same level, that at least two rows of lamps are placed under the grid, and in the gaps between the grid and the edges of the tunnel, at least one row of lamps, maintaining a minimum clearance between the grid and the lamp bulbs and, in addition, the inner surface the tunnels are polished to a mirror shine, and the lamps are divided along the length of the tunnel into three groups with the same electric power, connecting each group electrically to the controlled output of the three-phase voltage-temperature autoregulator, the control input of which is electrically connected to the temperature meter inside the tunnel and, in addition , the forms on the outside are covered with a layer of organosilicon heat-resistant black paint, and the ends of the tunnel are closed with elastically deformable curtains.

7. The essence of the invention is illustrated by drawings, where figure 1 shows a General view of a tunnel automated furnace (TAP) that implements the inventive method; figure 2 is a diagram of a transverse (in the middle of the tunnel) section of the tunnel along with the NIKI heater and conveyor; figure 3 shows a top view of the heater NIKI; figure 4 is a design diagram of the electrical connection of the emitters NIKI to the phase and neutral plate; figure 5 - diagram of a longitudinal section of the TAP; Fig.6 shows the connection of the tunnel with thermal insulation and with elastically deformable curtains, and Fig.8 is an electrical circuit for automatically controlling the power of NIKI emitters.

On the diagrams and in the text the following letter designations are accepted:

ARNT (figure 1, 8) - auto-regulator "voltage - temperature". Thyristor, three-phase, with current limitation in phases. Includes temperature setter and temperature indicator (not shown in the diagrams);

BUEP (figure 1) - control unit of the electric drive. Thyristor, single-phase inverter. Includes power frequency frequency adjuster and speed indicator (not shown in diagrams);

13L, 13P (figures 1, 6, 7) - respectively, the left and right curtains on the left and right ends of the tunnel 11;

TP (figures 1, 2, 5, 8) - a thermocouple;

VK (figure 1) is a common switch-on switch;

TI (figure 2) - thermal radiation of the heated tunnel body;

NIKI (figure 2) - directionally focused radiation in the near infrared from the emitters, i.e. from IKZ-500 lamps;

ONIKI (figure 2) - reflected (in the direction of focus F) from the inner surface of the housing of the tunnel NIKI;

HF (figure 2, 5) - bread forms (L7 - for large loaves of 700 g, L11 - for small loaves of 350 g);

AB (figure 2) is a part of the inner surface of the tunnel body 11 (in its cross section is an arc of a circle of radius R), which receives NIKI from the side row of NIKI emitters (IKZ-500 lamps) and reflects NIKI in the direction of focus F on the left;

VG (figure 2) is part of the inner surface of the tunnel body 11 (in its cross section is an arc of a circle of radius R), which receives NIKI from the side row of NIKI emitters (IKZ-500 lamps) and reflects NIKI in the direction of focus F on the right;

BG (figure 2) is a part of the inner surface of the tunnel body 11 (in its cross section is an arc of a circle of radius R), heated by thermal conductivity from sections AB, VG and heated air, which rises up. Thermal radiation TI of this heated part of the housing 11 is directed to the focus F;

L (figure 2) is the longitudinal clearance between the leading branch 5.1 of the conveyor grid 5

(Fig. 1) and the lower shelves of the longitudinal corners of the frame 7. The clearance L is 10 mm larger than the diameter of the bulb of IKZ-500 9.5 lamps, i.e. L = 134 mm + 10 mm = 144 mm on each side of the branch 5.1 of the grid 5;

f (figure 2) is the focal length, f = 1 / 2R;

F (figure 2) is the focus of the arc of the tunnel body 11;

R (figure 2) is the radius of the arc of curvature of the tunnel body 11 (trough);

R _a , R _b , R _c (Fig. 8) - equivalent (total in parallel connection) electrical resistances (phase load) in each of the three sections of the NIKI heater, R _a = R _b = R _s ;

a ₀ , b ₀ , c ₀ and n (Figs. 5, 8) - three-phase (380 V) electric power supply of the power input of the ARNT;

a, b, c and n (Figs. 1, 2, 3, 8) - designations of phases, phase wires and neutral wire from the controlled output of the ARNT;

9A, 9B, 9C (Fig. 3) - three identical in power sections of the NIKI 9 heater (Fig. 1) connected respectively to phases a, n; b, n; c, n controlled output of ART;

U ~ (figure 5) alternating voltage (industrial network 220 V, 50 Hz) of the supply of a controlled electric drive BUEP + 15 + 16 (indicated conditionally).

7.1. TAP that implements the inventive method includes the following structural elements.

To the fixed legs 1 of the steel corner (vertical) to the right and left are motionlessly attached (welded) horizontally to the frame-shelf 2 from the corner. On the frame-shelves 2, in the bearing supports (not shown in the figures), respectively, the leading cylinder 3 is mounted on the right, the driven cylinder 4 is on the left, covered by a conveyor net 5 with a tensioner 6 (Figs. 1, 2, 5). Conveyor mesh 5, respectively, has a leading branch 5.1 and a driven branch 5.2 (Fig.2, 5). The grid 5 is made of steel 12X18H10T wire with a diameter of, for example, 1 mm, with a rhombic or rectangular mesh size of 11 × 11 mm. Elements 3, 4, 5 and 6 are a mesh conveyor with a tensioning device.

To the upper ends of the legs 1, a supporting frame 7 is horizontally welded (fixedly attached), made of a steel corner and elongated along the tunnel automated furnace. To the lower shelves of the longitudinal corners (not shown in FIGS. 1, 3) of the frame 7, L-shaped plates 8 are welded vertically downward perpendicularly to the longitudinal corners of the frame 7, bent short ends towards each other. In pairs, these L-shaped plates 8 divide the space under the frame 7 into three identical parts. On the lower bent ends of the plates 8, NIKI 9 heaters are freely and motionlessly placed horizontally, each of which is connected to the controlled output of a three-phase (a, n; b, n; c, n) ARNT by electrical connection 10 (wiring) (Figs. 1, 2, 3, 4).

On the lower shelves of the corners (not shown in Figs. 1, 2, 3), the tunnel body 11 (Figs. 1, 2, 5) is freely laid, which is made in the form of a thin-walled trough made of a sheet of aluminum or an aluminum alloy bent along an arc of radius R 1.5-3.0 mm. The inner surface of the housing 11 is polished to a mirror finish. Opposite the edges of the tunnel body 11 is supported in the inner ribs of the longitudinal corners of the frame 7 motionless, free, but tight (figure 2). The bending radius R is set so that the focus of the arc F is located below the leading branch 5.1 of the grid 5 (figure 2). Outside, the tunnel body 11 is covered by thermal insulation 12, for example, of basalt felt 50 mm thick. In the middle of the length of the housing 11, inside it, through the thermal insulation 12, a TM thermocouple is mounted, which is electrically connected (during installation) to the control input of the ARNT (Figs. 1, 2, 5). Thus, the tunnel of the TAP furnace is limited by the space between the housing 11, the leading branch 5.1 of the grid 5 and the lower shelves of the longitudinal corners of the frame 7. The distance between the lower shelves of the longitudinal and parallel corners of the frame 7 is set so that at least two are placed under the leading branch 5.1 IKZ-500 lamps across the branch 5.1 with a gap of 40 mm between the lamps. So that between the branch 5.1 and the edges of the corners of the corners there should be a gap greater than the diameter (⌀ = 134 mm) of the bulb of IKZ-500 lamps by 10 mm on each side relative to the grid 5. The width of the grid 5 is set so that it (width) exceeds the total width at least two IKZ-500 lamps with a gap of 40 mm, for example, 40 mm or 20 mm on each side. In this case, the distance between the opposite edges of the IKZ-500 lamps under the branch 5.1 will be equal to the sum of the two diameters of the bulbs (268 mm) and the gap (40 mm) between them, i.e. 308 mm, and the grid width 308 mm + 40 mm = 348 ≈350 mm. At this mesh width 5, a cassette of three HF type L7 is freely placed, each of which (HF) has a width of 110 mm.

The heater NIKI 9 (figures 1, 2, 3, 4 and 5) includes the following, interconnected elements. On a dielectric plate 9.1, for example, from PCB, an electrically conductive bus (for example, a plate commensurate with plate 9.1) 9.2, for example, from duralumin D16, is fixed with screws with screws. Parallel to the bus 9.2, by means of the same dielectric partitions 9.4, a similar bus (plate) 9.3 is fixed, for example with screws (not indicated in the drawings), with screws. In the bus 9.3, identical through holes are made with a uniform gap from each other with a thread under the threaded lamp base

IKZ-500 (thread on the base E40). The bases (side contacts) of the IKZ-500 lamps are screwed into these holes until the lower contact of the lamps stops on the surface of the plate 9.2, for example, 16 pieces. The dielectric plate 9.1 is laid freely and horizontally on horizontally bent shelves of L-shaped plates with 8 lamps 9.5 up. Thus, three sets of NIKI heaters are assembled and stacked on horizontally bent shelves of L-shaped plates 8 along the leading branch 5.1 of grid 5. Each set, in accordance with the phases, by wiring 10, is connected to the controlled output of the ART. In this case, the lower tires (plates) 9.2 are connected to a neutral wire, and the upper tires (plates) are connected to the phase wires (Figs. 1-5, 8), respectively, to a, b, c.

The opposite ends of the tunnel casing 11 on the left L and right P are closed by elastically deformable curtains, 13L and 13P, respectively (Figs. 1, 6, 7). Each curtain 13 is made, for example, of aluminum foil with a thickness of 0.1-0.2 mm and its curved edge 13.1 curved in an arc is fixed to the end of the housing 11, for example, glued with heat-resistant adhesive or mastic, under thermal insulation 12. The flat surface of the curtains is similar to the contour of the end housing 11, i.e. represents a segment of a circle of radius R and a height equal to the cross-sectional height of the tunnel body 11, and is divided into strips 30 mm wide.

The leading cylinder 3 of the mesh conveyor by a chain drive (not shown in FIGS. 1 and 5), covered by a protective casing 14, is kinematically connected to the power shaft (not shown) of the geared motor (with rotary drive) 15. The geared motor 15 with a controlled motor (figure 1 is not indicated) is electrically connected by wiring 16 to the control unit of the electric drive BUEP.

7.2. The above tunnel automated furnace (TAP), implements the inventive method as follows.

When the power voltage is connected a ₀ , b ₀ , c ₀ and n (to the ARNT) and U ~ (to the BUEP), the inclusion of a common switch-switch VK (Fig. 1) provides the supply of power electric voltage (and current) to the ARNT and the BUEP - at the same time.

At the same time, both the NIKI emitters pos.9.5 and the drive pos.3, 14, 15 + BUEP are fully connected and are included in the work. At the moment of switching on (at an unspecified temperature and speed of the mesh conveyor), the NIKI 9.5 emitters in the NIKI 9 heater (9A, 9B, 9C) operate in the nominal mode (maximum NIKI power), and the grid speed 5 of the conveyor belt can have any permissible values.

Next, after turning on the VC, set the ARNT temperature setter (Figs. 1, 2, 5 and 8) to the set temperature, for example, 250 ° C inside the tunnel and the BUEP speed setpoint, the linear speed of the conveyor grid, for example, 10 cm / min.

Previously, the tunnel body 11 is made with a length of, for example, 2000 mm or 200 cm (the working length of the baking chamber of the tunnel), the mesh 5 is 350 mm wide, and the gaps L are 145 mm on each side of the mesh (FIG. 2). The NIKI 9.5 emitters (IKZ-500 lamps) are mounted according to Figs. 1, 2, 3, 4. Elastically deformable curtains 13L and 13P are installed at opposite ends of the tunnel body 11, which (the body 11) is covered externally with thermal insulation 12 (Fig. 5, 6 , 7). Under the leading branch 5.1 of the grid 5, on the L-shaped curved plates 8, three sections 9A, 9B and 9C (Figs. 1-3) of the NIKI 9 heater are placed with the same power. The gap between the leading branch 5.1 of the grid 5 and the lamp bulbs IKZ-500 (emitters NIKI 9.5) set to a value of 5 mm. In each section of the NIKI 9 heater, for example, 16 IKZ-500 9.5 lamps are installed. Nominal electric power of each section 9A, 9B and 9C is 8 kW. The total rated electric power of the NIKI 9 heater (in the electric load of the controlled power output of the ARNT) is 24 kW. At a rated electrical voltage of 220 V from the controlled output of the ARNT, such an electrical load provides heating of the air inside the tunnel body 11 to 450 ° C in 16 minutes.

When setting the temperature inside the enclosure 11 to 250 ° C, it is reached in 7 minutes. This temperature is sufficient for baking bread products (loaves) from rye and / or wheat dough in the forms of HF (L7 and / or L11). Upon reaching a predetermined temperature of 250 ° C, the HF forms filled with the test are installed on the moving driving branch 5.1 of the mesh 5 conveyor in the area of the driven cylinder 4, in front of the tunnel body 11. HF forms are installed along the branch 5.1, in a row (across the branch 5.1) three forms without gaps between them (Fig. 2 shows two HF with a gap between them). Along the length of the branch 5.1 of the grid 5, the rows of HF forms (for example, three pieces each) of the HF form are set either without gaps between the rows or with small gaps (Fig. 5).

On the leading branch, 5.1 HFs are held by friction of the bottom on the net (by the weight of the HF itself and the weight of the dough in it).

A number of HF forms (for example, of three pieces), moving inside the tunnel body 11, bends the elastic deformed curtain 13L (Fig. 5) into the body 11, while the left end of the body 11 (Fig. 5) remains closed from the air surrounding the tunnel. In the same way, the operation of exiting the baked bread (product) from the tunnel body 11 to the right (Fig. 5) is carried out in the region of the leading (drive) cylinder 3.

Products in forms (for example, in HF), moving together with the leading branch 5.1 of mesh 5 (Figs. 1, 2, 5) from the left curtain 13L to the right 13P, are heated together with the forms of HF. In the process of continuous movement of HF forms inside the tunnel body 11, a baking process, for example, of bakery products, takes place.

Heating (baking) occurs due to the constant temperature of the heated air (for example, 250 ° C), due to the heating of the HF forms from below and from the sides by means of NIKI from IKZ-500 9.5 lamps under the leading branch 5.1 of the grid 5, due to the heating of the HF forms from above and from the sides reflected from the side rows of lamps 9.5 (ONIKI) from the inner surface of the tunnel body 11 (Fig. 2), and products in the HF molds are heated from below and from the sides of the heated housings of the HF molds and part of the NIKI that penetrates the mesh and forms, and from above, in addition to air , and thermal radiation TI heated case 1 1 tunnel.

Thus, all the NIKI energy from the NIKI 9 heater (9A, 9B, 9C), Figs. 1, 3, is spent only on heating the HF forms, the test products in them and on maintaining the set air temperature during baking.

With the above parameters (mesh speed 5-10 cm / min; length of the shell 11 of the tunnel - 200 cm; temperature inside the shell 11 - 250 ° C; loaves of bread are baked) - every 2 min from the right curtain 13P of the shell of the tunnel 11 (Fig. 5 ) comes a series (of three pieces) of HF forms with baked bread. This corresponds (with no gap installation of the HF rows along the length of the leading branch 5.1 of the grid 5) of the TAP performance that implements the inventive method, 90 loaves per hour or 720 per shift. At the same time, the total consumption of electric energy to maintain a baking temperature of 250 ° C does not exceed 7 kWh. And the idle time (uselessly spent) is determined only by the heating time inside the tunnel body 11. For a maximum baking temperature of 250 ° C - in just 7 minutes. Further, baking occurs continuously for all three shifts.

7.3. The claimed technical results of the invention are achieved as follows.

7.3.1. The reduction in the cost of electrical energy for heating is due to the fact that radiation energy is not spent on heating the walls of the tunnel body 11 or any other body parts. Energy NIKI from emitters 9.5 (figure 2) is not absorbed by the material of the housing 11 of the tunnel (figure 2). Therefore, inside the tunnel space under the casing 11 and over the leading branch 5.1 of the grid 5, only NIKI, ONIKI and TI act. Moreover, the power of these emissions is not 10% (as in the prototype) of the rated radiation power of IKZ-500 lamps, but 95%, given the weak absorption of radiation by the housing 11, i.e. 9.5 times more than in the prototype, with the same rated power of IKZ-500 lamps.

All the energy radiated by the NIKI IKZ-500 lamps is spent only on heating the molds (bottom and sides) and products in the molds (top) due to the ONIKI reflected from the tunnel body 11 (FIG. 2) and the heat radiation of the heated body 11.

Mesh 5 (FIG. 1) with mesh sizes greater than 10 × 10 mm and a wire thickness of 1 mm does not prevent the penetration of NIKI through mesh cells on the bottoms and on the side surfaces of the HF forms (FIGS. 2, 5). Moreover, the mass of the grid 5 (due to the cells) is significantly less than the mass of the conveyor metal belts, therefore, the energy consumption of the electric motor for transporting (moving) the grid 5 is reduced.

So, for the implementation of the proposed method, a tunneling automatic furnace (Fig. 1) TAP with a shell length of 11 tunnels of 2 meters (capacity - 120 loaves per hour) for a grid 5 drive, an electric motor with a power of 250 W (0.25 kW) or 100 times less than the rated power of the NIKI heater 9 (Fig. 1), consisting of three identical sections 9A, 9B, 9C (Fig. 3) of 8 kW per section. Furthermore (grid speed - 10 cm / min), in order to maintain a maximum baking temperature of 250 ° C, an energy consumption of only 7 kWh is required. With a nominal electric power of the heater 9 of 24 kW, this is 3.4 times less than the rated power. Such high profitability is unattainable by other methods of baking (heating). An excess of 3.4 times the power of the heater 9 is necessary for quick heating of the baking zone - under the tunnel body 11 in 7 minutes to 250 ° C. This speed (speed) of heating is not achievable in all known methods of baking (heating). Upon reaching a predetermined 250 ° C temperature, which is measured by a thermocouple TP (Fig. 1, 2 and 8) connected to the ARNT (Fig. 1, 8), the ARNT reduces the supply voltage of the NIKI 9.5 emitters (IKZ-500 lamps) by 3.4 times, providing an energy consumption for heating of 7 kWh and maintaining a predetermined temperature of 250 ° C during baking.

The elastic deformable curtains 13L and 13P (Figs. 1, 5 and 6) at the opposite ends of the tunnel body 11 prevent the outflow of heated air from the baking area, prevent the entry of cooled (outside) air into it, so there is no need to increase the energy for heating inside the tunnel body 11.

7.3.2. The decrease in the material consumption of the structural elements of the method is due to the execution of the tunnel body from a plate curved in an arc around the circle, in the form of a trough. The open transverse profile of the housing 11 also simplifies the set of operations for its manufacture.

7.3.3. Simplification of the implementation of the method of baking bakery products in molds moving rectilinearly on the conveyor is achieved, as shown above, in that the body of the tunnel 11 (Fig. 2) is removable and easily replaceable, which easily changes to a reflector body 11 with a different radius of curvature, for example , for baking small confectionery (the volume of the baking zone decreases). At the same time, the functionality of the proposed method is significantly expanded in terms of the range (in size) of baked products.

A significant simplification of the implementation of the method is the absence of moisturizing (steam humidifiers) devices in the baking process, since they are not needed. In fact, the presence of elastically deformable curtains 13L and 13P at opposite ends of the tunnel body 11 prevents the formation of convection air flows within the baking region. Moisture evaporating from the dough forms a layer of saturated steam near the surface of the dough. This layer of saturated steam (in the absence of ambient air flows) is present inside the HF forms above the dough during the baking process until the HF forms with the product exit the tunnel body 11. Due to the low mesh velocity of 10 cm / min, there are no air streams that blow off steam. When leaving the housing 11, colder air condenses this vapor, turning it into moisture, which is absorbed by the heated and dried product

7.3.4. A significant increase in reliability, durability and maintainability due to the following.

Firstly, the tunnel body 11 is easily removable (together with thermal insulation 12), since it is not firmly fixed to the corners of the frame 7 (FIGS. 2, 6). In the event of an unexpected stop of the mesh conveyor 5 (Fig. 1), for example, when the mesh 5 is broken, the housing 11 is removed and unfinished products in the HF forms are removed from the baking area. After repair, the molds return to the leading branch 5.1 of the mesh 5, the housing 11 is replaced, the desired temperature and speed of the mesh 5 are set, and the baking process easily continues.

Secondly, sections 9A, 9B and 9C of the heater 9 can easily be moved to the right or left (Fig. 1, 2) from the length of the furnace along the bent shelves of L-shaped plates 8 (Fig. 1) without dismantling the phase connections (only the power is turned off by the VK switch ) This operation is necessary to replace burned out (damaged) IKZ-500 lamps in heater 9.

Thirdly, small electric voltages of power supply of electric lamps (3.4 times smaller than the nominal ones) during the baking process can increase the lamp life by (3.4) ¹³ or more than 8000000 times [29], since the working life (L _P ) of the lamps is calculated [29, p. 605]:

, $$L_{\text{Ð}}=L_H{\left(\frac{U_i}{U_{\text{Ð}}}\right)}^{13}$$

,

where L _H is the service life at rated voltage;

U _H - the value of the nominal voltage - 220 V;

U _P - the magnitude of the operating voltage - 65 V.

An important circumstance is the fact that the device for implementing the method - a tunnel automated furnace TAP, having low energy consumption, convenience and simplicity, also has a minimum dead weight compared to other known devices for implementing baking methods.

Information sources

1. Ostrikov A.N. and others. Workshop on the course "Technological equipment". - Voronezh: Voronezh State Technological Academy, 1999. - 309 p.

2. Khromeenkov V.M. Technological equipment of bakeries and pasta factories. - St. Petersburg: GIORD, 2003 .-- 496 p.

3. Patent RU No. 2441187, IPC F27B 9/00, publ. 01/27/2012.

4. GB patent No. 1281504 A, 07/12/1972.

5. Application for invention RU No. 20091688 C1, 09/27/1997.

6. Patent SU No. 832284 A1, 05.23.1981.

7. Patent SU No. 992976 A1, 01/30/1983.

8. Patent SU No. 679779 A1, 08/18/1979.

9. Patent SU No. 1725949 A1, 04/07/1992.

10. US patent No. 4568279 A, 04/02/1986.

11. US patent No. 4573909 A, 03/04/1986.

12. Patent RU No. 2313746 C1, IPC F27B 9/00, publ. 12/27/2007.

13. Application for invention RU No. 2008121359 A, IPC C03B 19/08, publ. 12/27/2009.

14. Patent RU No. 2146033 C1, 02.27.2000.

15. Patent SU No. 906828 A, 02.28.1982.

16. Patent SU No. 309881 A, 12/26/1971.

17. Patent RU No. 2417960, IPC C03B 25/08, publ. 05/10/2011.

18. Patent RU No. 2310616 C2, IPC C03B 19/08, publ. 11/20/2007

19. Jamison R.X. Physics and technology of infrared radiation. - M.: Publishing. Soviet Radio, 1965 .-- 535 p.

20. www.lisma-guprm.ru.

21. Nashchekin V.V. Technical thermodynamics and heat transfer. - M.: Higher School, 1980 .-- 469 p.

22. Patent RU No. 2430630 C1, Bull. No. 28, 10/10/2011.

23. Siegel R., Howell N. Radiation heat transfer. - M.: Publishing. Mir, 1975 .-- 934 p.

24. Patent RU 2457680 C2, A21B 1/48, F27B 9/00, publ. 08/10/2012.

25. Koshkin N.I., Shirkevich M.G. Handbook of elementary physics. The seventh edition is stereotyped. - M .: Nauka, 1976 .-- 256 p.

26. http://spectr.chb.ru/

27. Patent RU No. 2431793 C1, IPC F26B 3/34, Bull. No. 29 dated 10/20/2011.

28. Patent RU No. 2465526 C2, IPC F26B 3/04, Bull. No. 30 dated 10/27/2012.

29. Ulmishek L.G. Production of electric incandescent lamps. - L.: Energy, 1966. - 640 p.

Claims (1)

A method of baking bakery products in molds that move rectilinearly on a conveyor inside a tunnel covered with heat insulation from a tunnel oven, in which products are moved on the leading branch of a moving conveyor, heating the tunnel, products, branch and molds using directionally focused radiation in the near infrared region, supporting a predetermined temperature inside the tunnel automatically, characterized in that the molds are heated by this radiation from below and from the sides, and the products are heated from above by this radiation, reflected from the inside the lower surface of the tunnel, which is made in the form of a trough curved in an arc, curved upward, from an aluminum alloy, while the conveyor-conveying element is made in the form of a mesh conveyor with a stainless steel mesh containing chromium with a mesh size of at least 10 × 10 mm, positioning the leading branch of the grid horizontally along the tunnel at the level of its open free edges with the same gaps between the grid and these edges of the tunnel on the left and on the right, and these gaps along the width of the tunnel in the cross section and 10 mm larger than the diameter of the bulb of emitters, which use the same infrared reflector lamps IKZ-500, placing them vertically with the bulbs up along the tunnel under the leading branch of the grid in uniform rows with uniform gaps in a row at the same level so that at least under the grid are placed two rows of lamps, and in the gaps between the grid and the edges of the tunnel, at least one row of lamps, maintaining a minimum gap between the grid and the lamp bulbs, and, in addition, the inner surface of the tunnel is polished to a mirror shine and the lamps are divided along the length of the tunnel into three groups with the same electric power, connecting each group electrically to the controlled output of the three-phase voltage-temperature autoregulator, the control input of which is electrically connected to a temperature meter inside the tunnel, and, in addition, the forms are covered with a layer on the outside organosilicon heat-resistant paint of black color, and the ends of the tunnel are closed with elastically deformable curtains.

Images