In the confectionery industry, along with other processes commonly used heat treatment of raw materials and semi-finished products: heating, boiling, tempering, roasting.
When the thermal treatment of the product is a heat exchange between the product and the environment, donating or receiving heat energiyu- coolant or refrigerant. When frying the convective heat transfer of heat carried by the flue gases or hot air having a temperature 80-180 ° C.
The main heat transfer in thermal heating processes, dissolution and boiling in the confectionery industry is a saturated steam pressure of typically up to 0,7 MPa.
The following product heating methods with steam most common:
a) heating an open steam - steam sparging or a heated liquid inlet it into the machine by means of injectors;
b) heating the deaf steam - supply of heating steam to the steam heat exchanger chamber, where it condenses on the heat exchange surface, giving it the latent heat of vaporization.
open steam heating fluid usually produced by means of spargers or coil-tube with small holes through which the steam goes into the heated liquid; bubbler typically set at the bottom of the tank. The steam leaving the sparger orifices rises as bubbles in the path and is condensed, giving its heat to the heated fluid; wherein the fluid mixing occurs. The steam line diagram is required to include a check valve to prevent ingress of liquid into the vapor line when accidentally dropped a pair of pressure.
Essential disadvantages bubblers are noise generated at the output of the pair of holes, a pair of direct contact with heated product, as well as lower product concentration as a result of condensation of heating steam in it.
When heating the product deaf ferry across the heat transfer surface of the heat exchanger heating steam fills the steam chamber and heat exchanger, giving its heat exchange surface unit, is condensed. The condensate is withdrawn from the bottom of the steam chamber, automatic steam trap (steam trap or the retaining washer). Heat exchange surface may have a different design (steam jackets, coils, tubes and lines m. P.).
Transportation of liquid raw material (molasses, milk, etc.) From storage sites to sites cooking recipe mixtures dosing of raw materials and semifinished products by means of the plunger and gear pumps. To create a vacuum in the piston and wet-rotary vacuum pump units are used for boiling.
Apparatus for heat treatment of cocoa and nut kernels
When heat treated raw zhirsoderzhaschego removes moisture and volatile acids, improved taste, aroma and color. Kernels beans, nuts and seeds are fragile and easily broken up and crushed.
For the heat treatment applied, cylindrical and spherical (spherical) fryers batch and dryers Continuous type VIS-42DK Stroganov system, the EV and EVT Italian company "Carlo Montanari" type STR Swiss company "Buhler", type "Conti-303" (GDR) and others.
Cylindrical fryer. The device (Fig. III.1) is a welded drum 6, 7 rotating axis, which is driven by a pulley through 3 2 bevel gear. Under the drum is thin 11. The flue gases, washing the outer surface of a rotating drum, go into the flue 5. The raw material is loaded into a funnel 9, 10 attached to the door, and enters into the inner cavity of the drum, the surface of which spiral guide 7 reinforced stirring.
Evolved during roasting gases and water vapors are sucked through the pipe fan 8. Part of the flue gas passes through openings in the rear wall of the drum and the drum is sucked through the same ventilator. Drum immurated brickwork 4.
After roasting 10 door opens with a funnel and the product was poured into the paddock truck, which was then filed under the hood for the extraction of gas from the product and cooling.
The process of roasting these devices long. Regulation of temperature by varying the combustion rate, which makes it impossible to quickly adjust it.
The cylindrical devices are capacity 100 and 300 kg.
"Sirocco" Ball-type fryer. Inside the spherical shell 8 17 on a horizontal shaft rotates a hollow welded ball 4 (Fig. SH.2). Spokes 18 ball is attached to the two hollow trunnions 16 and 26, which can rotate freely on the shaft 17. The shaft has at one end 14 sprocket chain drive and the other - with the wheel 28 29 locking pin, which enters the hole 27 sector mounted on a hollow pin 26 4 ball. Thus, through the 29 27 pin and sector rotation of the shaft is transmitted 17 4 ball. bowl walls have holes for the discharge of the product, the closed damper 5.
The dampers are mounted on rods 6, 17 which are fixed to the shaft.
Raw materials (beans or nuts) is loaded into a funnel 3. When you open the damper, it gets into the inner cavity 4 the world. For mixing during rotation of the ball provided 7 blade. The device works on the gas heating.
Fan 1 sucked through the cavity sphere mixture of air and flue gases produced by burning coke in the furnace 15. At the same time the fan unit removes moisture vapor and gaseous products, isolated from beans or nuts. Air is sucked through the pipe 13. The amount of hot air and gas mixture entering the apparatus is regulated by the damper and 11 12. The temperature of the gases leaving the apparatus is controlled by a thermometer 2. gas suction fan enter the cyclone 25, where the separation of the shell of the particles occurs.
At the end of the roasting machine is stopped, the pin is pulled 29, 28 turn the steering wheel so that the valve 5 opened holes in the wall of the ball 4, 29 pin and release, which will be included in a corresponding hole 27 sector. After that include drive and the product during the rotation of the ball is poured into a conical portion 19 casing through the damper from 20 21 receiver enters the cooling apparatus.
Here, the product is mixed rotating blades 22. 24 fan sucked air through a layer of beans or nuts, located on the bottom of the mesh receiver 23 21.
When unloading the unit 11 and 12 dampers are closed and the gate opens 10 and hot gases from the furnace pass through 9 pipeline bypassing fryer.
The device is equipped with a device for automatic control of the roasting process. One of 17 shaft bearings based on the weight device that takes a lot of inner sphere and it is in the product. As remove
moisture of the mass of beans or nuts is reduced. When it decreases to a predetermined value, the weight of the device gives a signal to end the roasting process.
In recent years, to apparatuses mounted instruments to control and regulate temperature, gas flow and to reduce the weight of the product when it is roasted.
Technical characteristics of the fryer
|of, kg / h||обжарки, ° С|
|временно загру||of roasting,|
|zhaemыh bean, kg||min|
|Rotation frequency||20||33||OverallDimensions, mm||С обмуRovkov||With the cyclone and oven|
|cylinder and sphere,|
|rev / min|
Ball machines are available with a capacity of 160, 250, 400 and 750 kg.
Dryer VIS-42DK Stroganov system (rice ІІІ.Z). The chamber of this dryer is divided into 20 horizontal tiers with a height of 120 mm. The surface of each tier consists of a set of transverse plates (1000 × 110 mm). When you turn the plates on 90 ° cocoa beans poured on the lower tier. Mechanism
turning plates runs so that the beans are poured sequentially from the line on the floor. Initially, the first pivot plate, lower, tier, then the second and so successively until the top, after which the cycle is repeated. As the coolant is applied, hot air, heated in steam and electric heaters to a temperature 170-180 ° C.
To supply cocoa beans to the dryer is a tape dispenser to evenly distribute them in the top tier of plates - loading carriage. The heated air circulates along the shelves, moving successively to the lower tiers. The lower tiers of six blown air sucked out of the shop. Because of this there is a cooling of cocoa beans.
Raw material from the hopper 3 2 tape dispenser equal portions loaded into the drying chamber /. After a few minutes of the plate and turn the cacao beans are poured onto the underlying layer. When he reached the last, 20-th, a series of plates, dried and cooled to a temperature of 28-35 ° C cocoa beans enter the unloading auger and funnel 5 4 transferred to subsequent operations.
Exhaust air is sucked by means of exhauster 9, 5 cleaned in cyclones, partly emitted into the atmosphere and mixes with the fresh air fan 6 7 back on the air duct in paroelektrokalorifery 11. Heated to 180 ° C air through a nozzle 10 enters the drying chamber 1.
Dryer threading creates and allows the drying process to mechanize the loading and unloading. A major shortcoming of the dryer is uneven drying of cocoa beans and kernels, resulting in good average final moisture content of the product (2-3%) selected beans and kernels out nedosushennymi.
The disadvantages of the dryer should also include a partial breakthrough of hot air into the shop through the top plate and the complexity of the kinematic scheme.
Depending on the sort of cocoa beans dryer operates in two modes.
|And the regime||II режим|
|hot air temperature, ° C||175-182||163—170|
The temperature of the cocoa beans after roasting ° С
The duration of the heat treatment
The duration of cooling, min
|Technical characteristics of the dryer||VIS-42DK|
|Productivity, kg / h||600|
|The number of tiers of the dryer||20|
|The number of plates on the line||16|
|The total surface area of the tiers, m2||42|
|Number of steam heaters||2|
|The surface area of the radiator heating m2||39|
|Heating steam pressure, MPa||0,6—0,7|
|Power electric heaters, kW||36|
Number of fans
power supply with an electric motor
exhaust with motor power
|10 kW Airflow, m3 / h in the hot zone||Until 5200|
|Cooling zone||Until 4000|
|Overall dryer dimensions||6150X1990X3355|
Dryers type STR (Switzerland) and "Conti-303» (GDR).
Dryers of this type are single-channel dual-zone vertical dryer with a continuous closed loop motion teplonositlya.
The scheme of the STR dryer is shown in Fig. III.4. In the upper hot zone of 6, the products are airborne, heated in steam heaters, and in the lower zone - they are cooled by air supplied by the twin fan 10, and are removed through the branch pipe 1. Nuts, kernels or cocoa beans are continuously fed from the 4 bunker installed above the dryer and fill the channel-shaped vertical channel, the walls of which are made of a special mesh. In parallel, the channel is equipped with finned steam batteries-heaters 3} and on the opposite side - 8 screen filters for air purification. Due to the presence of filters, dryers of this type do not need cyclones to purify air from dust particles.
Continuous recirculation of air in the hot zone directly through the layer moving down from the top of the product is provided by two fans 5. They create an air stream is heated by steam heaters, and passing horizontally through the vertical channel of the dryer, the product gives off heat. After removal of fine particles in the filter, coolant 7 repeats its cycle of movement.
In operation, it enters the dryer in fresh air, and part of the air saturated with water vapor, is removed through pipe 2. The rating of the air dryer is regulated damper.
Beans or nuts, heat-treated, cold zone enter the channel 12 which can be separated
from the hot zone manually operated valve 11. The position of the last regulated by a special lever. This separation is required to work at the beginning of installation. It eliminates the lower zone filled product did not undergo heat treatment. The fan sucks 10 this zone through the closed window mesh 9 outside air that passes through the product bed and cools it. Is hot while the air passes through the filter and is directed partially into the vertical channel for update and partially removed from the dryer through a nozzle.
In the vertical channel of the dryer product moves by gravity. The speed of its movement is regulated 13 rotary valve, having a separate drive and speed variator, which control the wheel displayed on the working side of the dryer housing. On the same side of the control panel are located to the devices, the sampler and the choke lever separating heat treatment zone of the cooling zone.
Thermal treatment temperature is regulated within 80-150 ° C and maintained at the desired level automatically. Variable speed is also governed by the duration of product being in the zones. Dryers of this type provide uniform roasting of the product. Quality Roasting is controlled by the sampler.
Net channels, filters and heaters are easy to clean (clean filters daily, weekly grid and heaters). Good thermal insulation of the surface of the dryer allows you to install it with machines for primary processing of cocoa beans, nuts, seeds zhirsoderzhaschih.
Vertical shaft dryer type MU and EUT firm "Carlo Montanari" (Italy). In these dryers cocoa beans moved by gravity in a vertical shaft with fixed inclined shelves. Beans, pouring off the shelf pas shelf, go through the three hot spots, and then enter the cooling zone. The heated air heaters steam is blown by fans into the gaps between the flanges shafts, thereby passing across the flow of cocoa beans.
Technical characteristics of dryers
|Productivity, kg / h||250||500||200—250||500||630—1250|
|hot air temperature, ° C||80—150||80—150||80—150||80—150||180 when p = = 1,9 MPa; 135 when p = = 0,85 MPa|
Heating steam pressure, MPa
Overall dimensions, mm
Тeploobmennye apparatus for heating, boiling and tempering
For the heat treatment of raw materials and semi-finished products - the heating, evaporation (boiling) solution and for dissolving the raw material - are used in the confectionery industry different apparatuses batch and continuous.
For batch devices include:
open digesters, including dissutory - single-digesters to dissolve the sugar with a bubbler and heating coil;
spherical vacuum filling machines for boiling;
universal suction devices.
For devices of continuous action are:
Solvents for preparing the syrup, including sectional, screw-type, etc .;
coiled devices operating under vacuum - a vacuum chamber (mainly for boiling karamel- 11011 weight) or without vacuum - with a steam trap (for boiling fruit and berry fillings, various candy, dreamed, pasta, jelly and other confectionery mass);
coiled pomadovarochnye column for boiling fondant syrup, operating without vacuum, with steam traps;
heat exchangers film type.
Tempering various confectionery mass applied tempering machines, including:
cylindrical tempering machines, collections batch with steam-jacket and a stirrer for thermoregulation fillings, cocoa liquor, candy, chocolate and other masses;
automatic screw machines for continuous tempering of chocolate mass.
To create and maintain the vacuum suction devices mounted mixing condensers with wet-piston or rotary liquid ring vacuum pumps. To apply to devices for thermal treatment of mixtures and ready for removal of the masses used plunger, gear (revolving) or rotary gear pumps.