RU2277776C1 - Apparatus for thermal treatment of hardtack doughs - Google Patents

Abstract

FIELD: hardtack production, in particular, equipment for producing of rye, rye-wheat and wheat hardtacks.

SUBSTANCE: apparatus has carcass with drying, frying and cooling zones, heat generator, fans for feeding of air to heat generator and to cooling zone and for withdrawal of used heat-carrier from drying zone, hardtack dough charging branch pipe, gate for discharging of ready hardtacks, and conveyors for moving of hardtack doughs above each floor. Drying, frying and cooling zones are divided by means of partitions, valves and gates and are equipped with gas distributing floors and chambers. Heat generator is connected through branch pipes with frying zone chamber. Minimal sectional areas of distributing box under lower floor and of box between drying zone floors are smaller by 6-14 times than sectional area of branch pipe connecting heat generator with frying zone chamber. Chamber positioned between drying zone floors is equipped with partition dividing said chamber into two parts. Box connected to heat generator is located within one of said parts. Conveyors of drying and frying zones are furnished with individual drives for separate regulation of drying and frying process time.

EFFECT: increased efficiency in thermal treatment of hardtack doughs without employment of preliminary slight drying process, and improved quality of hardtacks.

3 cl, 4 dwg

Description

The invention relates to cracker production, and in particular to devices designed to obtain rye, rye-wheat and wheat crackers with dimensions of 10.5 × 10.5 × 10.5 mm or 6.6 × 6.6 × 25-40 mm The technology for the production of bread crumbs includes the following operations. Loaves of bread with a moisture content of 46-49% are initially cut into plates of the required thickness, and then into blanks, which are fed to a heat unit for drying, roasting and cooling bread crumbs. The resulting products are sieved and cleaned of crumbs, small and large fractions, sent to devices for oiling, specialization with various ingredients and packaging.

A known method of drying thermolabile materials implemented in the device (SU, No. 1043444, 05/23/1983) by repeatedly purging a layer of material with a drying agent when it is heated before each passage of the layer by introducing hot gases into it with a temperature not less than 1.5 times higher the temperature of the drying agent in front of the layer.

The disadvantage of the device according to this method is a significant (more than 1.5 times) excess of the temperature of the hot gases over the temperature of the drying agent, as a result of which it is not possible to have a frying zone with a significant cross section of the hot gas supply duct close to the minimum cross section of the hot gas supply ducts in the drying zone. Moreover, in the device according to the known method, two boxes are provided (three boxes in the claimed device), through which hot gases enter the grain dryer, and the grain is dried in succession in two layers. For comparison, when the drying agent is used successively in three layers of the dried material (three boxes of hot gas supply are necessary), due to a significant increase in the heat carrier moisture in front of the last layer, the drying process intensity is noticeably reduced (Methodological recommendations for mathematical modeling of the drying and cooling of grain in dense plants layer. M., VIESH, 1977, p. 26, Fig. 11). During the heat treatment of crackers, the most rational excess of the temperature of hot gases in comparison with the temperature of the drying agent is 10%. The significant excess of the temperature of the hot gases of the frying zone as indicated in the method compared to the coolant of the drying zone will result in either burnt crackers or a low intensity of the drying process. This causes a sharp increase in the dimensions of the unit and a decrease in the efficiency of the process.

A device is known for the heat treatment of bread crumbs, including a frame with drying, frying and cooling zones, a heat generator, fans for supplying air to the heat generator and cooling chamber and for removing waste heat carrier from the drying zone, the drying, frying and cooling zones being separated by partitions, valves and gates, have gas distribution floors and chambers, a pipe for loading workpieces and a device for unloading finished crackers, conveyors for moving workpieces over each table sludge, and the heat generator is connected by a pipe to the frying zone chamber (Patent RU 2233086 A, July 27, 2004, “Device for the heat treatment of crackers blanks”).

This device is the closest to the claimed. Its disadvantages include the reduced efficiency of the heat treatment process and the quality of the products. To obtain the optimum temperature of the drying agent (at a level of 10% below the temperature of hot gases), it is necessary to significantly reduce the amount of air cooling crackers, or the temperature of the drying agent will decrease by 20-25% compared with hot gases. The first leads to an insufficiently cooled cracker (with a temperature of up to 80 ° C), the second leads to a decrease in efficiency and an increase in the dimensions of the installation.

In the drying zone in the chamber between the decks, at the transition of the material from the upper to the lower floor, the coolant has high humidity and low temperature. As a result, conglomerates from crackers are formed on the tail of the upper flooring, which later go to waste. To eliminate this drawback, it is necessary to reduce the humidity of the coolant and increase its temperature. This can be achieved by adding hot gases into the chamber between the decks of the drying zone to the coolant partially worked out in the lower layer of the drying zone. The above not only improves the quality of products, but also increases the productivity of the installation.

The present invention is aimed at improving the quality of produced crackers, to increase the productivity of the installation and its effectiveness.

The claimed result is achieved by the fact that the chambers under the lower deck and between the decks of the drying zone are communicated with the heat generator through distribution boxes, and the minimum cross-sectional areas of the box under the lower floor and the box between the decks of the drying zone are 6-14 times smaller than the cross-sectional area of the pipe connecting the heat generator to the camera frying zones. In addition, in the chamber between the floors of the drying zone there is a partition that divides the chamber into two parts, and in one of them, under the section at the end of the upper deck, there is a box connected to the heat generator.

The indicated restrictions on the ratio of the cross-sectional areas of the ducts are determined based on the difference in overpressure (aerodynamic conditions) in the respective chambers of the device. In the operating thermal unit, the pressure in the hot gas supply chamber is at the level of 1700 Pa, in the chamber under the lower floor of the drying zone - 1200 Pa, in the chamber between the floorings of the drying zone - 600 Pa. Thus, the pressure difference in the hot gas chambers and under the lower floor of the drying zone is 500 Pa, and in the hot gas chambers and between the decks - 1100 Pa. At the indicated pressure drops and the cross-sectional areas in the boxes under the lower deck and between the floors of the drying zone, comparable with the cross-sectional area in the pipe from the heat generator to the frying zone chamber (with the ratio of the cross-sectional areas less than 6), hot gases will be significantly less than the required quantity. As a result of this, the roasting process will not be effective enough, and the dimensions of the device will increase. With small areas in the cross sections of the above distribution boxes of the drying zone (ratios of the cross-sectional areas above 14), the amount of hot gases in the drying zone will be so insignificant that the claimed device in its efficiency and quality of products will be close to the device offered as an analogue.

Figure 1 schematically shows a device for heat treatment of biscuits crackers. The device is a frame 1, divided into zones of drying 2, roasting 3 and cooling 4, each of which has respective chambers 5-8. In the zones of drying 2, roasting 3 and cooling 4, there are three gas distribution louvres 12 and three partitions 19 that separate the zones from each other. Moreover, in the partition that separates the drying zone from the other two zones, there is a hole 20, and the partition located between the decks of the drying zone does not reach the lower branch of the conveyor 15. The space between the decks in the drying zone from the ends is limited by valves 21. One above the chambers of the corresponding zones above the other there are two chain-slat conveyors 15 for moving the processed workpieces of crackers. The heat generator 16 is connected to the frying and drying zones by boxes 9, 10 and 11. A pipe 13 is provided in the frame for loading cracker blanks and a rotary shutter 14 for unloading finished crackers. The device includes two fans 17 for supplying atmospheric air to the heat generator and a cooling zone for crackers and a fan 18 for removing the spent heat carrier from the drying zone.

A device for heat treatment of biscuits crackers works as follows.

Through the pipe 13, the biscuits of crackers are loaded onto the upper gas distribution floor 12 of the drying zone 2 and conveyor 15 move them along the upper and lower floorings 12, while the necessary removal of moisture from the material occurs. The dried billets fall on the flooring 12 of the roasting zone and, using the second conveyor 15, move through the roasting zone 3 and cooling 4 to the discharge gate 14.

Atmospheric air is pumped by fans 17 into the chamber 8 of the cooling zone and into the heat generator 16. The hot gases heated in the heat generator 16 to a predetermined temperature enter the frying chamber through channel 9, and into the chambers 6 and 7 of the drying zone through channels 10 and 11. The hot gases worked out in the frying zone 3 and the air preheated after the cooling zone 4 are hung from the hot gases from the duct 10 and through the opening 20 in the partition 19 enter the chamber 6 under the lower floor of the drying zone. The heat carrier passing the material on the lower floor of the drying zone is divided into two parts. Most of it from the material loading side goes directly to the material to be dried on the top floor of the drying zone, and the smaller part is mixed with hot gases leaving the box 11. With reduced humidity and increased temperature, the mixture passes (at the end of the transition from one floor to another ) through the preparation of crackers, ensuring their quality without the formation of conglomerates. The result is an optimal temperature and humidity conditions for the implementation of the drying process.

Figure 2 presents the drying unit USS-1 with a capacity of 1 t / h for finished products, figure 3 is a fragment of the upper louvre sheet and chain-belt conveyor of the drying zone, and figure 4 is a conveyor unloading from the unit USS-0, 5 breadcrumbs.

Thus, the claimed device provides an effective and high-quality mode of drying, frying and cooling rye, rye-wheat and wheat crackers, allowing to obtain their properties that correspond to optimal organoleptic characteristics. In the production of other varieties of crackers, the temperature and humidity regimes of their heat treatment can be adjusted.

Positions and symbols in figure 1.

1 - frame;

2 - drying zone;

3 - roasting zone;

4 - cooling zone;

5 - chamber of the frying zone;

6 - a chamber under the lower floor of the drying zone;

7 - a chamber between the decks of the drying zone;

8 - camera cooling zone;

9 - box in the frying chamber;

10 - box into the chamber under the lower floor of the drying zone;

11 - box in the chamber between the decks of the drying zone;

12 - gas distribution louvres;

13 - pipe for loading crackers;

14 - rotary lock;

15 - conveyor for moving workpieces;

16 - heat generator;

17 - air supply fan;

18 - exhaust fan exhaust agent;

19 - partitions separating the drying, frying and cooling zones;

20 - holes in the partition for the flow of coolant into the drying zone;

21 - valve;

t _o - air temperature;

t _y is the temperature of the exhaust products of combustion;

t _g - temperature of hot gases in the frying zone;

t _g ¹ - the temperature of the coolant at the outlet of the frying zone;

t _c ^{1 is the} temperature of the coolant at the entrance to the drying chamber;

t _with ² - the temperature of the coolant after the layer of blanks on the lower floor of the drying zone;

t _s ³ - heat carrier temperature after mixing with hot gases in the chamber between the decks of the drying zone;

t _in - air temperature at the outlet of the cooling zone.

Claims (3)

1. A device for the heat treatment of bread crackers, including a frame with drying, frying and cooling zones, a heat generator, fans for supplying air to the heat generator and cooling zone and for removing the spent heat carrier from the drying zone, a pipe for loading workpieces and a shutter for unloading finished crackers, conveyors for moving workpieces over each deck, and the drying, frying and cooling zones are separated by partitions and valves, have gas distribution floors and chambers located underneath and the heat generator is connected by a pipe to the frying zone chamber, characterized in that the drying zone chamber between the decks is communicated with the heat generator through a distribution box, the minimum cross-sectional area thereof being 6-14 times smaller than the section of the branch pipe connecting the heat generator to the frying zone chamber. 2. The device according to claim 1, characterized in that the chamber between the floors of the drying zone is provided with a partition that divides the chamber into two parts and in one of them, under the section at the end of the upper deck, is a box connected to a heat generator. 3. The device according to claim 1, characterized in that the drying zone chamber under the lower floor is connected to the heat generator by means of a distribution box, and the minimum cross-sectional area is 6-14 times smaller than the section of the pipe connecting the heat generator to the frying zone chamber.

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