RU35954U1 - Installation for heat treatment of materials - Google Patents

Description

Installation for heat treatment of material.

The utility model relates to equipment of the food industry, in particular, to designs of bakery and drying ovens with radiation-convective heat supply to the working chamber, and can be used to make bakery products, bake straws, and dry crackers at confectionery factories and public catering establishments.

A known installation for the heat treatment of fibrous materials, comprising a working chamber, a perforated belt conveyor for moving material installed in the chamber, heating elements located above and below the carrier branch of the conveyor, a fan, the discharge pipe of which is connected with the cavity of the chamber between the branches of the conveyor, while working the chamber has an opening above the conveyor for the exit of the spent coolant. In this drying unit, radiation and convective heating of the carrier and idle conveyor branches occurs. Air is directed by the fan to the heaters, passes through the cells of the carrier belt of the conveyor, flows around the material on the belt and leaves through the hole in the upper part of the chamber (ed. Certificate of the USSR N 699302, publ. 25.11.79).

In this installation, the perforated carrier branch of the conveyor, for example, wire mesh, cannot serve as a hearth for baking bakery products, since it is heated only by the flow of heated air due to the lack of special.

Authors: Kychakov A. D. Kychakov A. A. IPC 7 A 23 G 7/02 A 21 V 1/48

a medium independent of the coolant for heating it to the necessary for baking

temperature. An increase in the temperature of the coolant flow for heating by a convective method makes the temperature of the coolant unacceptably high for contact with flour blanks.

Closest to the claimed utility model is a baking oven containing a baking chamber, in which there is a conveyor belt with a heater below it to heat the coolant and the hearth, air ducts with nozzles for supplying the coolant and a circulation fan, the discharge pipe of which is in communication with the heater and nozzles, and suction - with a baking chamber, while the upper wall of the air heater serves as a support for the conveyor hearth. The nozzles above the conveyor are mounted in contact with the heating elements and alternate with the suction channels. During the operation of the furnace, the bottom heating of the injected products is carried out from the conveyor hearth, which is heated when it contacts the upper wall of the air heater, and the products are heated from above by circulating the vapor-air mixture from the nozzles to the baking chamber and from the chamber to the suction channels, as well as due to radiation from the walls nozzles. (Auth. Certificate. USSR No. 1194348, publ. 30.11.85).

This baking oven cannot be used effectively as a dryer, since the upper wall of the air heater is solid, which does not allow creating heat carrier flows through the conveyor belt. Another disadvantage of this oven is the location of the idle branch of the conveyor outside the baking chamber, which leads to cooling of this branch and increased energy consumption.

The proposed utility model solves the problem of introducing into the installation for the heat treatment of the material a means for heating the conveyor hearth regardless of the heat carrier flow for the purpose of using the installation either for baking bakery products or for food products. comprising a working chamber with a belt conveyor located in it, equipped with a device supporting its supporting branch, heating elements located above and below the supporting branch, a circulation fan, the suction pipe of which is in communication with the working chamber above the conveyor, and the discharge is connected with a cavity between the branches of the conveyor using nozzles that create a coolant flow towards the direction of movement of the carrier branch of the conveyor, according to a utility model, the conveyor belt is perforated, devices Supporting bearing branch of the conveyor is in the form strips. attached to the cross members mounted in the side walls of the chamber, and the heating elements are attached to the cross members. In addition, the discharge pipe of the fan is additionally communicated with the cavity between the branches of the conveyor using nozzles that create a coolant flow in the direction of movement of the conveyor belt. Nozzles creating countercurrent coolant flows are located in the end parts of the working chamber. The execution of the conveyor belt perforated, for example, from a metal mesh, makes its carrier branch permeable to coolant flows, while the presence of injection nozzles under the carrier branch and a suction window above it allows blowing it from the bottom up. The implementation of the device supporting the carrier tape of the conveyor, in the form of strips attached to the cross members mounted in the walls of the chamber, allows this device to be purged with the same coolant flow. Attaching the heaters to the crossbars with straps, on which the conveyor mesh of the product rests, allows it to be connected to the heaters through metal and heat the mesh that carries the product to the temperature necessary for it to become the hearth of the baking oven, without resorting to increased heating coolant. Heating the hearth only by blowing the mesh with the coolant without directly heating it 3 through the metal would require an unacceptably high temperature of the coolant,

causing burning of the baked product. Independent of the temperature of the coolant, heating of the carrier grid allows, by lowering the temperature of the heaters of the carrier branch of the conveyor, to reduce its temperature and switch to the drying mode, blowing the product with coolant. In this case, the coolant is heated by heating elements above the conveyor.

The message of the fan discharge pipe with a cavity between the conveyor branches using nozzles located in the end parts of the working chamber and creating two oncoming coolant flows - in the direction of movement of the carrier branch of the conveyor and towards this direction - allows these flows to be simultaneously sucked through a window in the upper part of the working chamber create longitudinal flows washing products from the sides and from above and increase the uniformity of heating of the coolant along the entire length of the chamber.

Figure 1 shows the installation for heat treatment of material, a longitudinal section; in Fig.2 is a section aa of Fig.1; in FIG. 3 - a longitudinal section of the cross member with a strap and a heater.

The installation comprises a casing 1 with insulated walls that limit the working chamber, a belt conveyor, bearing 2 and idle branches of which are located in the casing; the ends of the conveyor exit the casing through the loading and unloading windows. The conveyor has a tension drum 3 and a drive station. The conveyor belt is made of metal mesh, its idle branch is in contact with the bottom of the casing, which has a window 4 on the loading side for the crumb exit.

The installation has a device supporting the supporting branch 2 of the conveyor, including longitudinal strips 5 in contact with the grid and fastened, for example, welded to the cross members 6, mounted in the side walls 7 of the casing 1. To the cross members 6 below are attached heaters 8, for example, tubular

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4 thermoelectric elements. Cross members 6 are made in the form of tubes open from below, in

which heaters are inserted.

The cavity 9 of the working chamber above the supporting branch 2 is equipped with heaters 10. The gaps between the strips 5 and the cross members 6, as well as the cells of the supporting branch 2 communicate between themselves a cavity 9 and a cavity 11 between the branches of the conveyor.

A circulation fan is installed on the casing 1, the discharge pipe 12 of which is connected by air ducts to the nozzles 13.14 located in the end parts of the cavity 11. The outlet openings of the nozzles 13.14 are facing each other to create two coolant flows - towards the movement of the carrier branch 2 and in the direction her movements.

The suction pipe 15 of the fan is connected by an air duct to a socket 16 located at the upper wall of the casing 1 in its middle part and facing the branch 2.

The discharge pipe 12 of the fan is connected to a pipe 17 having a gate for adjustable removal of part of the vapors of the pitch.

A steam humidifier can be mounted at the inlet of the unit when used for baking, and at the outlet, a cooler.

For baking small products, such as cookies, the supporting branch 2 has removable sheets located on the conveyor grid with gaps from each other.

As a baking oven, the installation operates as follows.

Dough pieces laid on the supporting branch 2, which is the hearth, or on the sheet, enter the cavity 9, that is, into the baking chamber, where they are subjected to radiation-convective and contact heating when moved to the right (according to the drawing). The grid of the supporting branch 2 is heated due to contact with the strips 5, heated from the heating elements 8 through the cross-members 6. The air from the nozzles 13,14 flows in opposite streams to the middle of the working chamber and rises upward, being sucked in by the bell 16. In this case, the air heats up, flowing around the heating elements 8, 6, strips 5 and passing through the grid of the carrier 2 and idle

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5

branches of the conveyor, the latter being also heated by heat radiation from heating elements 8. Heated air flows around the counter and rising upward flows of the workpiece, ensuring uniform heat treatment from the sides. From above, the preforms are subjected to radiation heating from heaters 10. The heated steam-air mixture is sucked into the fan bell 16, from where it is again fed through nozzles 13.14 into the cavity 1. A part of the steam-air mixture together with the vapors is discharged into the pipe 17 for discharge into the atmosphere. The amount of discharged mixture is regulated by the gate. Dry cold air from the working room enters the baking chamber through the loading and unloading windows. The crumb through the grid cells of the conveyor is sifted to the floor of the chamber, is shifted by the idle branch to window 4, and is poured into the tray. Heaters 8, 10 are connected with equipment for setting their temperature. The set temperature of the heat treatment zones is maintained automatically from the temperature sensors in the baking chamber.

When using sheets, the dough pieces are laid on them with a spreader, the sheets are installed on the conveyor. The size of the gaps between the sheets necessary for communicating cavities 9 and 11 is found empirically.

When the unit operates as a dryer, the lower heaters 8 turn off or lower their temperature compared to the temperature of the bakery, if during drying of a particular material, contact heating leads to burning, which occurs with a significant loss of moisture when drying is completed. The heat carrier during drying is heated mainly from heaters 10.

The use of the claimed utility model allows, in comparison with the prototype, to expand the technological capabilities of the installation for heat treatment of material. The authors . Kychakov A.D. 6

Sgchakov A.A.

Claims (3)

1. Installation for heat treatment of material containing a working chamber with a conveyor belt placed in it, equipped with a device supporting its supporting branch, heating elements located above the supporting branch of the conveyor and below it, a circulation fan, the suction pipe of which is in communication with the working chamber above the conveyor and the discharge is connected with the cavity between the branches of the conveyor using nozzles that create a coolant flow towards the direction of movement of the bearing branch of the conveyor, characterized in that, with In order to ensure the possibility of creating a coolant flow through the carrier branch of the conveyor and heating it by transferring heat from the heaters through the metal, the conveyor belt is perforated, the device supporting the carrier branch of the conveyor is made in the form of strips attached to the cross members mounted in the side walls of the chamber, and heating elements attached to the cross members. 2. Installation according to claim 1, characterized in that the discharge pipe of the fan is additionally communicated with the cavity between the branches of the conveyor using nozzles that create a flow of coolant in the direction of movement of the carrier branch of the conveyor. 3. The installation according to claim 2, characterized in that the nozzle creating countercurrent coolant flows are located in the end parts of the working chamber.