The closer summer gets, the more the desire to lose weight and get in shape grows. But for those who spent a long winter eating hastily pasta, sausages and sandwiches, it is difficult to adapt to new way. Most fitness trainers agree that drying pasta is not allowed. However, nutritionists have a different opinion.

Arguments for and against drying pasta

Opponents of pasta give the following arguments for abandoning it:

• high glycemic index (rapidly increases blood sugar);
• presence of gluten;
• high calorie content.

Nowadays, only diabetics and nutritionists without deep knowledge pay attention to the glycemic index. According to their beliefs, when a lot of glucose enters the blood, our body, striving for a constant composition, can only utilize its excess into fat. That’s why high GI is bad for them. However, for such a scenario, the glycogen depots of the liver and muscles must be overfilled, which does not happen on a diet.

Gluten-free diets do not contribute to drying in any way (but do not interfere with it); they are only needed for people with celiac disease.

As for calorie content, in 100 grams of boiled pasta, buckwheat and rice it differs by no more than 5–10 calories. It is believed that foods with a higher glycemic index fill you up for a shorter period of time, but the absorption of food and subjective hunger/satiety from it depend not only on the GI. Someone is hungry after a plate of buckwheat, and after the same, but pasta, they are full. There is no problem if you eat pasta with chicken rather than rice with breast meat, but still meet your daily carbohydrate requirements.

What kind of pasta can you cook and how to cook it?

Those who are on a diet face another danger with pasta: this product contains very few biologically active substances. During drying, the amount of food is limited, so it must have high nutritional value, maximally satisfying the needs for vitamins and minerals. In order not to become too dry to the point of vitamin deficiency, you should choose pasta:

• made from whole grain flour (whole grains contain more B vitamins), despite their unappetizing grayish or brown color;
• with additives - tomato, spinach, buckwheat, etc.

To preserve the beneficial components, they need to be undercooked - served al dente.

Losing weight and cutting is not a reason to completely give up your usual foods. Rather, the reason is to reconsider their amount in the diet and methods of preparation.

Raw pasta is a convenient environment for various biochemical and microbiological processes to occur. To prevent the development of these processes, products are subjected to canning by dehydration - drying to a moisture content of no more than 13%.

Drying pasta is the longest stage of the pasta production process. Such indicators of the quality of the finished product as strength, glassiness of the fracture, and acidity depend on the correctness of its implementation. Very intense drying can lead to cracking of products; excessively long, as well as under-drying, leads to their souring, and when drying in a layer, to the formation of ingots and deformation. Drying is completed when the humidity reaches 13.5-14%, so that after cooling their humidity is no more than 13%.

In compacted pasta dough and raw products, a large proportion of moisture is bound osmotically. During drying, adsorption and osmotically bound moisture is removed, with the less strongly bound osmotic moisture being removed first, and then the more strongly bound adsorption moisture. First of all, moisture bound by starch is removed, and then proteins are dehydrated. When drying, the dough releases moisture extremely slowly, so to control the dehydration process, it is necessary to take into account the entire set of properties of pasta dough.

There are two reasons why moisture is removed from products:

1) the temperature difference between the material being dried and environment

2) the difference in humidity between the outer and inner layers of products.

Methods for removing moisture:

1) contact- pasta is placed on a preheated surface, the products are heated and moisture is removed.

2) convective– is based on heat and moisture exchange between the material being dried (raw pasta) and heated drying air, which blows on the product. The drying process involves bringing the moisture inside the product to its surface, converting the moisture into steam, and removing steam from the surface of the product. According to this scheme, osmotically bound moisture is removed. Adsorption-bound moisture turns into steam inside the product and moves to the surface in the form of steam.

3) radiation, i.e. transfer of energy from the emitter, heated to a high temperature, to the product by magnetic vibrations.

4) sublimation– drying a pre-frozen product with removal of ice in a high vacuum.

In most cases, pasta is dried by convection..

When drying pasta using the convective method, heated drying air performs the following functions:

Provides the material with the energy (heat) necessary to convert water into steam

Absorbs steam evaporating from the surface of products

Removes evaporated steam from the surface of products.

Therefore, the higher the air temperature, the more intense the evaporation of moisture from the material; the lower its humidity, the more intensely it will absorb evaporating moisture. Also, the intensity of drying depends on the speed of air movement over the material: the higher the air speed, the faster the evaporated moisture is removed from the material.

Convective drying modes depending on air temperature:

1) traditional low temperature modes– drying air temperature does not exceed 60 0 C

Drying pasta in cabinet heatless dryers of types VVP, 2TSAGI-700, “Diffuser”.

Drying of short-cut products in steam conveyor dryers of types KSK-4G-45 and KSK-4G-90.

Hanging drying of long products in dryers of automated production lines B6-LMV, B6-LMG.

The main disadvantage of traditional low-temperature drying modes is the long duration of the drying process.

2) high temperature conditions- the air temperature at a certain stage of drying reaches 70-90 0 C.

3) ultra-high temperature conditions- drying air temperature exceeds 90 0 C

Drying mode– this is a set of drying air parameters (t, w speed), drying duration, the presence of drying and refrigeration periods, their duration and alternation frequency.

The ideal drying regime is one in which the internal mass transfer of moisture does not lag behind the moisture transfer from the surface of the product. However, it is difficult to implement such a regime, because The drying process slows down very much, which can cause the product to sour. To speed up the drying process and obtain products good quality in the initial period (with dough humidity up to 20%), they are dried under harsh conditions, i.e. with intensive air blowing with high drying ability. Then, to avoid cracking, drying is carried out under softer conditions, when moisture is slowly removed by air with low drying ability. This process must be carried out especially carefully at the last stages of drying, when the humidity of the products is below 16%. In practice, these conditions are met when drying products in production line dryers, where the process is divided into 2 stages - preliminary and final drying.

Drying modes depending on the drying ability of the air:

1) three-stage or pulsating– consists of 3 stages:

a) pre-drying– lasts from 30 minutes to 2 hours. During this time, from 1/3 to 7% of the moisture evaporates, which must be removed from the products. The process is carried out under harsh conditions, because The dough is flexible and there is no danger of cracking. The purpose of this stage is to speed up drying, stabilize the shape of raw products, and prevent them from stretching, molding and souring.

The dough leaving the pre-drying chamber must have a moisture content of at least 20%. The crust formed on the surface can cause cracking of the product during further drying, therefore, to soften it, the products are sent for chilling.

b) rejuvenation– blowing with hot air with a relative humidity of 90-100%. In this case, practically no evaporation of moisture from the surface occurs, and the supplied heat is spent on warming up the products and equalizing the humidity in the inner and outer layers of the pasta tube.

c) final drying– run under soft conditions, because products acquire elastic properties, and the rate of moisture evaporation from their surface must be commensurate with the rate of its supply from the inner layers to the outer ones. At this stage, the processes of drying and defrosting are sequentially alternated, and the ratio of drying duration to refrigeration time is approximately 1:2.5.

A similar method is used for drying long products in a suspended state in automatic production lines LMB, B6-LMG and in the lines of foreign companies “Pavan”, “Braybanti”. All these lines consist of a press, self-weighing, dryers for preliminary and final drying, a stabilization chamber and an installation for removing products from bastuns.

Drying air parameters in the pre-dryer – t=35-450С, w= 65-75%. The final dryer is a tunnel divided along its length into drying zones and dampening zones. Air heaters and fans are installed in the drying areas. Air temperature in the final drying zone is 35-45 0 C, w = 70-85%. The height of the final drying tunnel is divided into several tiers, along which bastuns with products pass sequentially, alternately crossing the drying and cooling zones.

2) air drying with constant drying capacity

In this mode, the air parameters remain approximately constant from the beginning to the end of drying (t = 35-45 0 C, w = 65-75%). The major disadvantage of this mode is that drying has to be carried out at a high drying capacity of the air. This mode can be used for products that are most resistant to deformation: soup fillings and short-cut products. Drying occurs in a shorter time, their sizes are smaller, and they are better amenable to comprehensive blowing when pouring.

This method is used in factories for drying pasta in cassettes in heat-free dryers such as GDP, Diffusor, 2TsAGI-700. Drying duration is 20-24 hours.

3) air drying with variable drying capacity

It is used in continuous belt conveyor steam dryers used for drying short-cut products, such as PKS-20, PKS-40, KSA-80, SPK-45, SPK-90. Dryers are a chamber, inside of which there are 5-5 conveyors with products moving in opposite directions, one above the other. In this case, the product is sequentially poured from the upper belts to the lower ones and blown with air heated in the heater. Drying duration is 30-90 minutes depending on the size of the products. Fresh air is heated by a lower heater to 50-60 0 C and has a humidity of 15-20%. Passing through the layer of products on the bottom belt, the air gives off some of the heat and is moistened. Rising upward, it is heated by a second heater to the same temperature, passes a layer of products on the second belt, etc. As a result, at the exit from the dryer its temperature reaches 40-50 0 C, and the relative humidity is 50-60%, i.e. drying is carried out with air with varying drying ability.

To soften the drying regime and improve the quality of products, 2 dryers are installed in series, the first serves as a preliminary dryer, the other as a final dryer. The total drying time is 1-3 hours, including 0.5 hours in the preliminary chamber. A similar mode is used in automatic production lines for drying short products.

4) drying with preliminary heat treatment of raw products

Such drying consists of blowing tubular products with a porous-air mixture at a temperature of 95-98 0 C and a relative humidity of 95% for 2 minutes and short-cut products with dry steam at a temperature of 120-180 0 C for 30 seconds, followed by drying at a constant drying capacity of the air .

This treatment of products before drying significantly reduces the dehydration process, because allows the use of harsh drying modes without fear of cracking. In this case, two interrelated processes occur: thermal denaturation and gelatinization of starch.

Drying molded sliced ​​pasta is the final stage of pasta production, on which the quality of the product depends. It is carried out in special drying devices that use a convective method of heat supply.

A pasta drying plant consists of a chamber where the product is dehydrated; heater where the drying air is heated; supply and exhaust system for supplying heated air and removing exhaust air.

The heater can be located both inside the drying chamber and outside it. Depending on the method of heating the coolant, air heaters with water or steam heating are used.

Depending on the design, drying units are divided into drum, conveyor and cabinet, and according to the principle of operation - into continuous, cyclic and periodic.

Pasta drying plants differ in the ways of placing the dried material inside the chamber (frames, cassettes, bastuns, cells) or devices for moving it.

The classification of pasta dryers is shown in Fig. 22

Rice. 22. Classification of dryers for pasta

Equipment for drying short pasta

Pre-dryer unit

The installation is intended for primary drying of pasta, carried out in order to prevent them from sticking together during further drying. Automated lines for the production of short pasta are equipped with such installations.

The Braibanti pre-drying installation consists of two identical sections (left and right), operating simultaneously and independently of one another. The sections are rigidly connected using ties and have a common skin, which gives the installation the appearance of a single, complete structure. The installation is located under the press platform, between its supports.

The main components of the installation (Fig. 23) are a sieve block with a drive mechanism and a heating and ventilation system. Each section has a welded frame 1 made of rolled steel. Inside each section, five metal vibrating sieves 8 are located one above the other. Each sieve is a stainless steel mesh stretched over a rectangular wooden frame and fixed in a metal frame. At the ends of each of the four upper sieves (as the product flows) there are rectangular windows through which raw products are poured from top to bottom from sieve to sieve. The lower sieve is connected to tray 6, which protrudes beyond the chamber on the side opposite to the loading.

A screen drive consisting of an electric motor, a V-belt drive with two-stage pulleys, an eccentric shaft and two pairs of connecting rods is fixed to the wall of the frame on the product unloading side.

The first pair of connecting rods is connected to a set of the first, third and fifth sieves, the second - to a set of the second and fourth sieves. During operation of the installation, sets of sieves perform reciprocating movements in opposite directions relative to each other, which ensures the movement of raw products along the first, third and fifth sieves forward, and through the second and fourth in the opposite direction.

Thus, moving through the sieves from top to bottom, the raw product successively passes about 10 m, during which time up to 2% of moisture is removed from the products.

Fig.23. Installation "Braybanti" for pre-drying

On the end sides of the chamber frame of each section, two heaters 3 and two axial eight-bladed fans 4 are installed under the sieves. Hot water (90 °C) is supplied to the heaters in an amount of 2.5 m 3 /h. Fans continuously supply hot air, forcing it through the screen block. Air is taken from the workshop premises through control dampers 2 and 5 in the chamber casing. The centrifugal fan 7 installed on the end wall of the chamber section is designed to remove excess moist exhaust air from the section.

The chamber casing consists of a wooden frame, lined on the inside with 3 mm thick wood fiber boards, and on the other side with laminated paper. Between them is laid a thermal insulating material - polystyrene foam.

To facilitate access to fans, electric drives and heaters, the chamber walls are removable.

Conveyor dryers Dryer SPK-4G-45

(Fig. 24). It consists of the following main parts: five belt conveyors 4, two drive columns 12, steam heaters 2, a ventilation system 9 and a dryer control panel.

The frame 1 of the dryer is prefabricated metal, the outside is lined with metal panels, and has doors. To monitor the process of product drying, sampling, cleaning screens and repairs, removable panels with windows 7 are installed on the sides of the dryer, and doors are installed on the end sides.

Figure 24. Dryer SPK-4G-45:

1 - frame; 2 - heater; 3 - mesh belt, 4 - belt conveyor, 5 - gates;

6, 11-collector; 7 - window; 8-angle thermometer; 9 - ventilation system; 10 - gates;

12-drive column

Inside the dryer, one below the other, there are five pairs of drums, each with a diameter of 340 mm, on which a metal mesh belt 3, 2000 mm wide, made of stainless steel is stretched, with a total drying surface of the belts of 45 m 2. Each pair of drums is offset in length relative to the other, which allows the product to flow from belt to belt.

To clean the surface of the drums from adhering product, scrapers are installed on all five tension drums. In places where the product is poured from the upper belt to the lower one, rotary gate guides 5 are installed.

The dryer is heated by steam fin heaters located between the driving and driven branches of the mesh belts of all five conveyors. Heater 2 of each conveyor consists of two series-connected batteries. Each battery consists of two longitudinal pipes with a diameter of 44.5/39.5 mm with holes into which 16 transverse pipes with a diameter of 38/33 mm are inserted.

Control of the steam pressure entering the dryer is carried out by OBM-160 pressure gauges installed on the inlet and outlet 11 manifolds.

The dryer is equipped with a ventilation system, which consists of two exhaust chambers made of 1.5 mm thick sheet steel and installed above the upper belt of the dryer.

Each chamber contains one axial fan. Rotary dampers 10 are installed inside the exhaust chambers in front of the axial fans, with the help of which you can change the amount of exhaust air passing through.

The movement of the dryer belt conveyors is carried out from two drive columns 12. From the first, the first, third and fifth belt conveyors are driven. The rotation of the drive drums is carried out from an electric motor through a V-belt drive, a chain variator, a chain drive, a worm gearbox and a chain drive system. From the electric motor of the first column, through a V-belt drive, a worm gearbox and a chain drive, one shaft with brushes installed at the end of the second conveyor belt rotates.

The second drive column has a similar design; it drives the second and fourth driving drums of the conveyor belts, as well as rotates two shafts with brushes installed at the end of the first and third belts.

Above the three upper belts there are turners, which are a shaft with rods attached to it. It is located across the belt, and when the rods rotate, they mix the dried products, preventing the formation of ingots.

Using a spreader, raw products are transferred to the upper belt of the dryer, where they quickly move over the heaters of the upper tier. In this case, more than a third of the moisture to be removed evaporates.

Next, the product enters the second belt, which moves somewhat more slowly over the heaters of the second tier. Drying here also continues quite intensively, removing approximately another third of the moisture.

Then the products are transferred to the third belt, which moves even more slowly over the heaters of the third tier; about 4% of the moisture is removed on this belt.

The fourth and fifth belts have even lower speeds, and during the time spent on them the product finally dries to standard humidity.

In the process of pouring products onto the belts, fine flour crumbs are formed, which pass through the cells of the belts and are collected in the lower part of the dryer on pallets. Drying air passes through the dryer from the bottom up, is heated in heaters and cooled, passing through conveyor belts with the product. Moisture removed from products is released into the atmosphere through exhaust fans.

Dryer SPK-4G-90. The dryer of this brand differs from SPK-4G-45 in that it has large working areas of conveyor belts and productivity. The SPK-4G-90 dryer has the same belt width (2000 mm), but due to its greater length, it has a total working surface of 90 m 2.

The main disadvantage of steam conveyor dryers is that they use a mode with increasing air drying capacity. Since the product flow and the drying air flow are directed towards each other, drier products located on the lower conveyor belts are dried with drier air than raw products on the upper conveyor belts, and the effect of sagging of the conveyor belts is also observed.

Drum dryers

Drum dryer "Romet" installed in an automated line from the Italian company Braibanti. The Romet drum dryer (Fig. 25) consists of two mesh cylinders with a diameter of 1600 and 2400 mm, inserted into one another.

Fig.25. Romet drum dryer:

a- diagram; b - cells; 1 - partition; 2 - profile; 3 – window

The cylinders are fastened to each other using rims and 24 transverse ties. To give the structure the necessary rigidity, six hoops with special clamping devices are installed along the outer perimeter of the drum.

The internal space between the cylinders is divided by metal partitions (Fig. 25, b) 1, and each section along its entire length is divided by special curved profiles 2 into separate cells with windows 3 (50 cells). This design ensures that when the drum rotates, the product is poured into the cells and its gradual movement along the section. In one revolution of the drum, products are poured from one cell to another; in 50 revolutions of the drum, products pass through all the cells of one section in sequence.

To ensure the necessary technological conditions of the drying process, all four sequentially installed drums are covered with heat-insulating panels. Between the upper ceiling and the drying drums there are axial fans and radiator batteries. Each dryer has six axial fans with a power of 1.1 kW each and one centrifugal suction fan. The entire line system is supplied with hot water by a 1.1 kW pump.

Adjustment of the amount of fresh air taken into the dryer and exhaust air discharge are carried out automatically in predetermined ratios. To do this, in the upper ceiling above each dryer there are three openings for fresh air intake, each of which is closed with dampers using a system of rods and a gearbox. A damper is also installed on the suction pipe of the centrifugal fan.

The product enters the first drying drum from the vibrating dryer through two vibrating trays. For this purpose, two loading windows measuring 300x400 are provided in the lining of the end part of the drying tunnel. The ends of the vibrating trays are mounted on flexible vertical supports on the floor of the room. The transfer of product from one dryer to another is carried out using a transfer device, which has prefabricated vertical and inclined trays.

Equipment for drying long pasta

Depending on the method of placing products inside the dryer, equipment for drying long pasta can be divided into three main groups:

The first unites a group of dryers where the method of drying pasta in tray cassettes is used. These are cabinet dryers of periodic action VVP, 2TSAGI-700 and “diffuser”. This group includes mechanized tunnel dryers of the Ufa and Volgograd pasta factories and LS-2A designed by Rospishchepromavtomatika;

The second group of cyclic conveyor dryers is represented in the automated lines B6-LMG, B6-LMV of the Rostov-on-Don Machine-Building Plant and lines of the Italian company "Braybanti". These dryers use a hanging method for drying pasta on metal racks;

The third group of continuous conveyor dryers is represented in the automated lines of the French company Bassano. Here, a combined method of drying pasta is used in a preliminary dryer - on frames, and in a final dryer - in cylindrical cassettes.

Cabinet dryers

Cabinet dryers are a cabinet closed on three sides, which has a channel for air passage and a slot for installing drying cassettes with products. The open part of the cabinet is used for loading and unloading products, as well as for air intake and exhaust.

Dryer GDP(Fig. 26). It is a drying chamber 1, open on one side for loading cassettes 2. In its upper part there is a casing in which a reversible fan 4 with an electric motor 3 and a collector 5 are installed to direct air into the vertical channel 6. A TsAGI axial reversible fan No. is installed inside the casing. 7.

The frame of the drying chamber is made of wooden blocks, covered with plywood and bolted for strength. The chamber contains 156 double or 312 single cassettes. The width of the chamber accommodates three rows of cassettes, and the height – 26; The length of double cassettes accommodates two rows, single cassettes – four rows. The working volume of the drying chamber is 2 m 3. The fan impeller is installed in a streamlined manifold that directs the air flow into a vertical channel. The use of a collector provides better conditions for fan operation and helps to increase its efficiency.

Rice. 26 Dryer GDP:

1- drying chamber; 2 - cassette; 3 - electric motor; 4 - fan; 5 – collector, 6 – channel

Drying of pasta is carried out at a temperature of 30-35 o C and a relative air humidity of 60-70%. Cassettes with pasta are fed from the installation for cutting and laying out pasta or from the cutting table on a conveyor or in trolleys to the drying room and are stacked in the drying chamber. The reversible fan rotates in one direction, takes air from the workshop, directing it through the layer of products. This is followed by a short stop of the fan and then turning it on again with rotation at reverse side, while the direction of the air flow is opposite to the original one. Then the cycle repeats.

Organizing the process of reversing the air flow in the drying chamber allows you to dry the product more evenly across the depth and cross-section of the cabinet. The total duration of the drying process is 14-16 hours. The cassettes with dried pasta are removed and transported to the packaging department, and the cabinets are refilled with raw products.

Dryer 2 TsAGI – 700(Fig. 27). It is a drying chamber 3, open on two opposite sides, divided in height into two sections by a shelf 1, in which one TsAGI axial reversible fan No. 7 5 with an electric motor is installed.

Fig. 27 Dryer 2- TsAGI-700:

1- shelf; 2- socket; 3 – drying chamber; 4 - mesh; 5- fan; 6- trolley with products

On each open side of the cabinet there are 2 slots for loading cassettes.

Electric motors and fans are fenced on both sides with metal meshes 4, which serve as limiters for the cassettes when installing them in the dryer slots.

The frame of the dryer is made of wooden blocks and covered with plywood. Stands for installing electric motors are welded from metal corners.

Dryers can be used as non-stationary ones; in this case, 1-2 rolling trolleys 6 with products are placed on each side of the fan head. Each trolley contains 156 single or 78 double cassettes.

The 2TsAGI-700 dryer differs from the GDP in its increased air speed at the inlet to the products (4-5 m/s) and 1.5-1.8 m/s at the exit from them, due to the presence of two fans with an almost identical cross-section of the nest. Increased air speed and a smaller area of ​​blowing products by each fan ensure more uniform drying of products in the layer, reduce drying time and, accordingly, increase product removal from 1 m 2 of area occupied by the dryer.

Dryer productivity 1.0-1.2 t/day. with a process duration of 12-14 hours.

When operating the dryer, make sure that both fans rotate simultaneously in the same direction.

To ensure uniform drying of the product on both sides of the cabinet, these dryers also use fan reversal.

Dryer "double-sided diffuser"(Fig. 28) consists of a ventilation chamber 2 with a one-sided or double-sided (as shown in the figure) “diffuser” and, accordingly, one or two drying chambers. Instead of cabinets, one or two trolleys 5 can be rolled up to the ventilation unit and secured with ties.

Each trolley contains 156 single or 78 double cassettes.

Reversible fan 4 is installed in manifold 3. The fan electric motor is mounted on a metal welded support 1.

Rice. 28 Dryer "double-sided diffuser":

1 - support; 2 - ventilation chamber: 3 - collector; 4 – fan;

5- trolley with products; 6 – mesh

The ends of the collector are covered with safety metal mesh 6.

In a “double-sided diffuser,” drying air is drawn from the room on one or the other side of the dryer and passes through pasta tubes located in cassettes. Just like in previous dryers, the rotation of the fans is periodically reversed.

The design of a relatively elongated diffuser helps to equalize the air flow speed, which has a positive effect on the uniformity of drying across the cross-section of the cabinet.

The operating mode of the dryer is similar to the previous ones.

Rice. 29. Tray drying cassettes:

A- wooden double, b- metal single

Dryers use tray wooden or metal cassettes (Fig. 29). Dimensions of wooden cassettes (in mm): single - 225x365x70, double - 454x365x70; The capacity for dry products, depending on the assortment, is 2 -2.5 and 4-5 kg, respectively. Metal cassettes are made from aluminum sheets measuring 225x364x68 mm, the capacity of the cassette for dry products is 2-2.5 kg.

The disadvantage of cabinet dryers is that, for purely technical reasons, it is impossible to regulate the parameters of the drying air in the dryers themselves. Therefore, drying in them is carried out according to the workshop regime without taking into account changes in the structural and mechanical properties of pasta during the drying process. The operation of such dryers requires significant manual labor. Many operations - transporting cassettes with products to the drying room and back, loading and unloading drying cabinets - are performed manually.

Therefore, at pasta enterprises, where possible, cabinet dryers are replaced with other, more modern equipment.

To facilitate access to fans, electric drives and heaters, the chamber walls are removable.

The peculiarity of such dryers is that cassettes with semi-finished products are installed in stacks on chain conveyors, which, when moving, pass along ventilation units. To ensure the required temperature conditions, product conveyors and ventilation units are isolated from the drying room using a prefabricated metal frame lined with thermal insulation boards. Cassettes are loaded with semi-finished products from one side of the tunnel, and unloaded from the opposite side.

Dryer LS2-A(Fig. 30). It consists of the following main parts: a drying tunnel 7 with a set of axial fans 5, two chain conveyors 18 for moving the product, a conveyor 6 for returning empty cassettes, a ventilation system for supplying air to the drying tunnel and exhausting exhaust air from it.

Inside the tunnel, along its entire length, twelve cabinets are installed close to each other, in each of which two axial fans of the TsAGI type No. 7 are mounted. The axial fans in the cabinets are installed so that the direction of air movement of adjacent cabinets is opposite. This achieves a change in the direction of air blowing of the pasta as it moves. On both sides of the cabinets, through the entire tunnel, there are two chain conveyors to move the product. On the loading side of the dryer, the conveyors extend 1300 mm out of it; on the unloading side, roller conveyors 9 with a length of 7000 mm are installed to the chain conveyors. Roller conveyors serve as storage areas for finished products.

The drive of the chain conveyor is carried out from an electric motor 13 through a V-belt speed variator 12 and three sequentially installed gearboxes 11. Warm air is supplied to the drying chamber through an air duct 17 by a centrifugal fan 16 through a heater 15. The exhaust air is sucked out from the upper zone of the dryer at the end of the tunnel by a centrifugal fan 14. A necessary condition for the operation of the dryer is some excess air pressure inside the drying tunnel, while the flow of air into the dryer through the door leaves and other gaps is not allowed.

The drying tunnel is divided into two drying zones: the first, from the entrance to the tunnel, is the pre-drying zone of products, it contains two cabinets; the second is the final drying zone, which includes ten cabinets. The drying zones are separated from each other by a partition, and there are doors for the passage of cassettes through them. In both zones of the drying tunnel, the required temperature (35-41 °C) and relative humidity of the drying air (55-75%) are automatically maintained by adjusting the operation of the heater and electromagnetic valve.

The dryer operates in the following order. On two conveyors, stacks of 2 cassettes with raw pasta are stacked close to each other, 22 cassettes high and two wide for each conveyor. A total of 2816 product cassettes are installed in the dryer. As the conveyor moves, the cassettes with their mass open the doors of the drying tunnel and are blown by an air flow from axial fans. After drying, cassettes 10 with dried pasta are transferred from chain conveyors to roller conveyors, from which the products are sent for packaging. The return of empty cassettes is carried out by a belt conveyor, which has the opposite direction to the chain conveyors.

Cassettes 8 are placed one at a time on the horizontal part of the belt conveyor located between the roller conveyors. The cassettes are moved over the drying tunnel to tray 1 to be lowered to the loading point. Rolling down the tray, cassettes can accumulate on its horizontal part, therefore, when the tray is filled with cassettes, under the influence of their mass, the moving part of the horizontal guide of the tray is lowered and the limit switch is activated, which stops the cassette return conveyor.

Fig.30. LS2-A dryer diagram:

1-tray; 2,8,10-cassettes; 3.11 gearboxes; 4.13 - electric motor; 5 - fan; 6-belt conveyor;

7-drying tunnel;9-roller conveyor;12-speed variator;14,16-fans; 15-heater; 17-duct; 18-chain conveyor

Automated conveyor dryers

Long pasta products are dried by hanging using low-temperature drying modes, mainly in dryers of automated production lines B6-LMV and B6-LMG and other foreign companies (Braybanti, Pavan, etc.).

Removing moisture from raw products hung on bastuns is carried out in two stages: in preliminary and final dryers. Pre-drying takes place under relatively harsh conditions in the first drying chamber and final drying under intermittent conditions (alternating drying and defrosting) in the second drying chamber.

Pre-dryer B6-LMV(Fig. 31). Designed for pre-drying of long products on the B6-LMV and B6-LMG lines. The same dryer is installed on the Braibanti line with a capacity of 24 tons per day. The B6-LMV pre-dryer is a heat-insulated and sealed tunnel 5, in which three comb conveyors 7 are located.

The tunnel is divided by a ceiling into two floors, which form two drying zones. In the first (lower) zone there is one comb conveyor, in the second (upper) - two. At the bottom of the dryer there is a conveyor 7 for returning empty drums.

The dryer frame is assembled from separate welded sections, which are connected with bolts. Dryer assembly elements are installed inside and outside the frame.

The dryer drive transmits movement to the mechanism for moving the bastuns 9 in the horizontal direction to the chain conveyor 6, which transfers the bastuns from tier to tier (from one comb conveyor to another) or from the preliminary dryer to the final dryer.

Fig.31. Pre-dryer B6-LMV

The dryer drive transmits movement to the mechanism for moving the bastuns 9 in the horizontal direction and to the chain conveyor 6, which transfers the bastuns from tier to tier (from one comb conveyor to another) or from the preliminary dryer to the final dryer.

Bastuns are moved horizontally using comb conveyors. Each conveyor consists of a pair of parallel guides and combs.

The guides are attached to the inner surfaces of the dryer walls, on which the trunnions of the bastuns with products rest. The combs move along a closed quadrilateral:

Lifting - the trunnions of the bastuns lie in the depressions of the combs and rise above the guides;

Forward movement - bastuns with products move along the drying tunnel one step equal to 31 mm;

Descent - the trunnions of the bastuns lie on the guides, and the combs go down;

- backward movement - the bastards remain in place, and the combs idle in the opposite direction.

Thus, the baskets with products gradually move along the dryer tunnel, and on the first and third conveyors - in one direction, and on the second - in the opposite direction. The drying air is heated using red heaters 3 made of finned pipes. Each drying zone

has its own air heating system.

Water at a temperature of 80...90 o C is supplied to the heating system of the first zone directly from the central heat supply system of the factory. To enable condensation of water vapor in the lower zone of the bear, pipes are laid in the floor through which hot water circulates.

The ventilation system of the first and second drying zones operates with partial recirculation of drying air: moist air from both drying zones is partially discharged into the room, and partially mixed with drier air entering the dryer from the room.

Ventilation of the second zone is carried out by eight centrifugal fans 8 located in pairs on the sides of the dryer. Three pairs of fans recirculate drying air by partially sucking air from the room, and one pair sucks out moist air from the first and second zones and throws it into the room.

To ensure uniform blowing of heated air over the products, the dryer is equipped with grates 2. The products are blown from top to bottom.

The specified drying air parameters (temperature and relative humidity) are maintained by an automatic control system.

The tunnel frame lining consists of two layers of separate panels with sealed joints between them.

Each internal shield has a wooden frame, covered on both sides with cardboard.

The frames of the external panels are lined with cardboard on the inside, and on the outside with fire-resistant paper laminated plastic. Between the panels there is a layer of casting foam.

The purpose of the pre-dryer is to quickly remove moisture from raw pasta at the stage when they have plastic properties. The main purpose of this stage is to reduce the overall drying time of the pasta.

In addition, a rapid decrease in humidity prevents the development of microbiological processes - souring and molding of products.

The drying air parameters in the pre-dryer, depending on the range of products being dried, are: temperature 35... 45 °C, relative humidity 65... 75 %.

The duration of pre-drying on the B6-LMV and B6-LMG lines is about 3 hours, the humidity of the products leaving the pre-dryer is no more than 20%.

Final line dryerB6-LMV(Fig. 32) . It is a tunnel, the lining of which is the same as that of the pre-dryer. The tunnel contains five comb conveyors 6, which move bastuns 12 with products along the dryer.

From one comb conveyor to another, underlying one, bastuns with products are transferred using chain transferrs 7.

The operation of comb conveyors is similar to their operation in a pre-dryer. Along its length, the dryer tunnel is divided into three drying zones, between which dehumidification chambers are located. The drying air in the drying chambers moves through channels 11 located on the side and top of the chambers.

Each chamber is equipped with two centrifugal fans 2 (on one side and the other) and two sections of water heaters 5 from finned tubes: in the first zone - between the second and third, fourth and fifth tiers, in the second and third zones - between the first and second, third and fourth tiers.

The fans suck in the air that has passed through the products, which are placed on the fifth (lower) comb conveyor, and supply it upward through the side channels. From here it is sent to the drying chamber, blowing sequentially from top to bottom the products on all tiers and being heated in air heaters. Fresh air is sucked into the dryer through holes 1 in the walls of the dehumidifying chambers.

Exhaust air is discharged into the room through openings 8. The dampers of openings 1 and 8 open and close automatically.

The air temperature in the drying zones, as well as in the pre-dryer, is 35...45 o C, and the relative air humidity is 70-85%.

Fig. 32. Diagram of the final dryer B6-LMV for long products

In the cooling zones, the relative air humidity is close to saturation - 100%, so moisture does not evaporate from the surface of the products. In these zones, the moisture content of the product is equalized across all internal layers: a slow migration of moisture inside the products to the surface from which moisture was removed while the products were in the previous drying zone. At the same time, the humidity gradient inside the products decreases and internal shear stresses resolve.

Thus, the removal of moisture from the semi-finished product is carried out in the final dryer in stages: drying periods constantly alternate with periods of refrigeration. This mode is called a pulsating drying mode, which results in the formation of strong products with a glassy fracture.

At the end of the final dryer, two axial fans 9 are installed, which suck in air from the room, blow through heaters 10 and create an air curtain that prevents air from entering the dryer at the point where the bastuns with dried products exit.

At the bottom of the drying tunnel there is a chain conveyor 4 for returning empty drums to the self-weighing line. To prevent vapor condensation, pipes 13 are laid under the dryer, through which hot water circulates.

The duration of final drying of products depends on the assortment and on average is 11...12 hours on the B6-LMV line, 14...15 hours on the B6-LMG line. Next, products with a moisture content of about 13.5% are sent for stabilization and cooling to a tunnel-type storage stabilizer.

Final line dryerB6-LMG. Designed for final drying of long products on the B6-LMG line. The same dryer is installed on the Braibanti line with a capacity of 24 tons per day.

This dryer differs from the final B6-LMV dryer in that it has one more drying zone and one more dehumidifying chamber.

The batteries of water heaters are installed in the first and third drying zones under the second and fourth conveyors, and in the second and fourth zones - under the first and third conveyors.

PRODUCTS DRYING MODES USED IN INDUSTRY

The most optimal drying mode for a certain type of pasta is considered to be one that produces products of normal quality (primarily in terms of strength and acidity) with the shortest drying time and energy consumption.

However, in practice it is not always possible to create and strictly maintain optimal drying conditions. Often it is necessary to work under conditions that can only be carried out on a given drying equipment and under given conditions, that is, it is necessary to create so-called rational drying regimes with their closest possible approximation to the optimal ones.

Drying pasta in cabinet dryers. Despite a number of significant disadvantages, drying pasta in tray cassettes in cabinet heatless dryers is most common in pasta enterprises. This is explained by the fact that this type of drying does not require complex, expensive equipment and large production areas.

Drying of the product is carried out in cabinet heatless dryers such as GDP, Diffuser and 2TSAGI-700.

Cassettes filled with raw pasta are placed either on carts, which are taken to the drying department, where the cassettes are installed on the shelves of drying machines, or in vagonet cabinets, which are placed close to the drying cabinets.

Cassettes on the shelves of drying machines or in trolleys are stacked in several rows in width and height. No more than four rows of single or two rows of double cassettes are installed in depth.

Cabinet dryers are equipped with ventilation units, which consist of one or two axial fans mounted on electric motor shafts. Drying of pasta is carried out by blowing air through pasta tubes lying in cassettes. Air from the workshop is used to dry the pasta. For the most uniform drying, periodically (every 1 hour) change the direction of air movement to the opposite, switching the electric motor to work in the opposite direction.

In the drying shop, air parameters are maintained at a constant level using supply and exhaust ventilation, i.e. the air has a constant drying ability, namely: a temperature of about 30°C and a relative humidity of 65-70%. The air in the workshop is heated either by a battery of heating radiators or by a heater, through which fresh air is pumped into the workshop instead of the humidified exhaust air sucked from the workshop. The drying time at the specified air parameters should be from 20 (for large-diameter pasta) to 24 hours (for small-diameter pasta). The desire to reduce drying time by using drier air or increasing the speed of movement leads to large quantity cracked pasta.

When drying in tray cassettes, pasta is subjected to air blowing from the inner and outer surfaces of the tubes. However, due to the uneven contact of the pasta with each other, uneven removal of moisture from their surface occurs, and, consequently, uneven shrinkage of the products.

This leads to severe curvature of the products during drying, which significantly reduces their quality and increases the consumption of packaging containers.

In addition, the close contact of the tubes in the cassette and the inability to quickly remove moisture in the initial stage of drying often lead to sticking of products and the formation of ingots.

However, the use of mechanized production lines does not eliminate the remaining disadvantages of the cassette drying method, so the pasta industry is focusing on the gradual introduction of more modern automated production lines.

Hanging drying of long items. Drying long pasta (vermicelli and noodles) different types, pasta straws and special ones) by hanging method is carried out in our country in tunnel dryers of automated production lines B6-LMG, B6-LMV, LMB and in the lines of the Italian company Braibanti. Products hung on racks move slowly in the dryer tunnels, blown with air from top to bottom.

The listed lines differ from each other in power or design of individual elements, but the drying principle in them is identical. All lines include, in addition to a press and automatic self-weighing of raw products onto bastuns, preliminary and final dryers, as well as a stabilization chamber and an installation for removing dry products from bastuns (see Fig. 11).

The purpose of the pre-dryer is to quickly remove moisture from raw pasta at the stage while they have plastic properties. The main purpose of this stage is to reduce the overall drying time of the pasta. In addition, a rapid decrease in the humidity of products prevents the development of various microbiological and biochemical processes, primarily souring and darkening.

The drying air parameters in the pre-dryers of the listed lines are approximately the same and, depending on the range of products being dried, are: temperature 35-45°C, relative air humidity 65-75%. However, depending on the design of the pre-dryers, the length of time the products remain in them and the amount of moisture removed are different. Thus, the product spends an average of about 60 minutes in the pre-dryer of the LMB line, while its humidity is reduced to 25-26%. This dryer does not fulfill its purpose, since the humidity of the semi-finished product at the pre-drying stage can be reduced to 20%. It is to this value that the humidity of raw products is reduced in the pre-dryers of the B6-LMV, B6-LMG and Braibanti lines. The pre-drying time on these lines is about 3 hours.

The final dryers of automated production lines with hanging drying of products are a tunnel divided along the length into drying and cooling zones.

In the drying areas, fans and heaters are installed, with the help of which the drying air is heated and blows over the products hanging on the racks.

The air temperature in the final drying zones is, as in the preliminary dryer, 35-45 ° C, and the relative air humidity is slightly higher - 70-85%.

In the cooling zones, the relative air humidity is close to saturation (100%), so there is no evaporation of moisture from the surface of the products. In these zones, the moisture content of the product is equalized across all internal layers: a slow migration of moisture inside the products to the surface from which moisture was removed while the products were in the previous drying zone.

In this case, the internal shear stresses resulting from this removal are resolved.

Along the height of the final dryer tunnel there are several conveyors along which bastuns with products pass in succession, alternately crossing the drying zones and the cooling zones. Thus, moisture is removed from the product in stages, drying periods alternate with periods of refrigeration. As a result of the so-called pulsating drying mode, durable products with a glassy fracture are obtained.

The duration of final drying of products depends on the assortment and on average is 16-18 hours in the LMB line, 11-12 hours in the B6-LMV line, 14-15 hours in the B6-LMG and Braibanti lines. Emerging from the final chamber dryers, products with a humidity of 13.5-14% are sent to a stabilization chamber for cooling.

The drying process here is also divided into two stages - preliminary and final. During pre-drying, moisture is relatively quickly removed from the semi-finished product, laid out in one layer on mesh frames: in 2 hours the humidity of the product is reduced to 21%. Here, the products, which are still plastic material, are placed inside cylindrical cassettes (drums). Each cassette is made of perforated stainless steel sheet and is divided inside by partitions into several sections, the length of which corresponds to the length of the pasta. In these cassettes, pasta undergoes a final drying stage, during which, in order to avoid cracking of the products, the zones of intensive air blowing of the cassettes (drying zones) also alternate with refrigeration zones. The total duration of final drying, depending on the type of product, is 10-12 hours.

	Brand	Lines
Options	LMB	B6-LMV. B6-LMG
		And the Braibanti company
Pre-dryer
Air temperature, °C
lower tier	37-42
vermicelli production		33-38
	40-45	35-40
upper tiers		38-43
vermicelli production
production of noodles and pasta		40-45
Relative humidity, %
lower tier
vermicelli production	65-75	65-75
production of noodles and pasta	65-75	65-75
upper tiers		70-80
vermicelli production
production of noodles and pasta		65-75
Drying duration, min, not less
The moisture content of the semi-finished product at the end of the tier, “and
first	26-25	26-24
second		24-22
third		22-20
Final dryer
Air temperature in drying zones, °C
in the first (lower) zone	35-40	37-47
vermicelli production
production of noodles and pasta	38-45	40-50
in the second (upper) zone	33-38	35-45
vermicelli production
production of noodles and pasta	35-42	38-48
Relative air humidity in the drying zone, %
in the first		75-85
vermicelli production	70-80
production of noodles and pasta	70-80	75-85
in the second	75-85	80-85
vermicelli production
production of noodles and pasta	75-85	80-85
Drying duration, h, not less
Humidity of the semi-finished product at the end of the tier, %
first	22-21	19-18
second	19-18	17,5-16,5
third	16,5-15	16-15
fourth	14-13,8	15-14
fifth		13,8-13,5
Humidity of products after stabilizer, %

In the final drying tunnel, the drums perform rocking or rotating movements, causing the products to roll along their inner surface. This drying method results in completely straight products,
which ensures uninterrupted operation of filling machines and saves packaging materials. In addition, compared to the hanging method, drying in rotating cassettes makes it possible to produce pasta of large diameters.

Approximate drying modes on Bassano lines, which may vary depending on different types of products, are given in table. 12.

Drying short-cut products in steam conveyor dryers. The overwhelming majority of short-cut products are dried in our country in steam conveyor dryers. Raw products are distributed by a spreader onto the top conveyor of the dryer, slowly moved in the opposite direction, poured onto the belt of the next conveyor, and so on - to the bottom conveyor, which is fed for unloading.

Layers of products lying on conveyor belts are penetrated by drying air, which is sucked into the bottom and discharged at the top of the dryer. Fresh air is heated by a lower air heater to a temperature of 50-60 °C and a relative humidity of 15-20%. Then the heated drying air passes through the layer of products lying on the lower conveyor, gives off some of the heat and is moistened. Having passed through the second heater, the air is again heated to approximately the same temperature, a layer of products lying on the mite of the second conveyor passes through, and so on, up to the upper conveyor. The parameters of the exhaust drying air at the outlet of the dryer are approximately the following: temperature 40-

50 C, relative humidity 50-60%. This drying mode is called a mode with increasing air drying ability: as the product dries, it is blown with drier air.

Table 12. Approximate mode of drying long products on the line

"Bassano"

Technological parameters	Preliminary Telnaya Dryer STRANSLAX"	The final dryer "Miiii-Rol i- ioks"	Finalist Naya Dryer "Rolyiox*
Drying air temperature, °C
Relative humidity of dryer
air, %
Drying duration, h
Humidity of products at the end of the chamber, %			12,5

The duration of drying of products (to a humidity of 13.5-14%) is, depending on the assortment, from 30 (for noodles and soup fillings) to 90 minutes (for large figured products). The thickness of the layer of products on dryer conveyor belts should be no more than 5 cm.

The use of such harsh drying conditions often leads to the formation of cracks on the surface of the dried products, especially tubular (feathers, horns) and figured (shells, etc.). But, despite this, drying short-cut products in steam conveyor dryers remains the most common at our enterprises. This is explained primarily by the high productivity of these dryers despite their small overall dimensions, as well as the relative ease of their maintenance and operational reliability.

To soften the drying regime and obtain more durable products, two steam conveyor dryers have recently been installed in series. In this case, the first dryer serves as a preliminary dryer, and the second as a final dryer. The parameters of drying air at the inlet recommended by the VNIIHP pasta production laboratory, i.e. immediately before contact with the products lying on the bottom belt of the dryer conveyor, are as follows: in the pre-dryer - temperature 55-65 ° C, relative humidity about 50%; in the final dryer - temperature 50-60 ° C, relative humidity about 60%. The total drying time, depending on the type of product and the type of dryer, is 1-3 hours, of which in the pre-dryer - about 0.5 hours. The thickness of the product layer on the conveyor belts should not exceed 5 cm.

Drying short products in dryers of automated production lines.

Drying of short products (short-cut and stamped) in dryers of automated production lines of foreign companies is carried out in three stages. The already familiar stages of preliminary and final drying, which are carried out on these lines in dryers that differ from the steam conveyor dryers just discussed only in the number of conveyors and the system for heating and blowing products with drying air, are preceded by an additional stage of primary drying. This stage is carried out in installations for primary drying (trabatto, shaker), inside of which several mesh rectangular frames are located one above the other.

The frames perform reciprocating movements, which causes the sequential movement of raw products from the top frame to the bottom.

	Options The products seem to “jump”, being blown with hot air. Within 2-3 minutes of keeping raw products in the installation, a dried crust forms on their surface, preventing the products from sticking together during subsequent drying on conveyor dryer belts. To obtain a high-quality durable product in dryers of automated foreign production lines		companies use softer drying modes than in domestic steam conveyor dryers. Recommended drying parameters are given in table. 13. Drying Air Sch - 3	X S o S K rfr- (U	And O 1>S J3 I
Semi-	The end Tanov-	Drying unit	Temperature,	°C [ Humidity, Thickness of the upper body: tapes no more Yoo * = H - O X	Tt £ oh I WITH *
S about	35 - 45	60-70		2-3 min	27-2S
Noah drying Pre-dryer
Pressed products	37-47	60-70		40 min	20-22
Stamped products	33-43	60-70		30 min	20-22
Final dryer
Pressed products	40--50	70-80		8 hours	13,3-13,5
Stamped products	35-45	70-80		7 hours	13,3-13,5
Stabilizer-storage	25-30	60-65			Raw pasta is a convenient environment for various biochemical and microbiological processes to occur. To prevent the development of these processes, products are subjected to canning by dehydration - drying to a moisture content of no more than 13%. Drying pasta is the longest stage of the pasta production process. Such quality indicators largely depend on the correctness of its implementation. finished products, such as strength, fracture glassiness, acidity. Very intensive removal of moisture can lead to cracking of products, excessively long drying at the first stage of moisture removal can lead to souring of products, and when drying in a layer, it can lead to the formation of ingots and deformation of the product. Drying of pasta is carried out by convective method, which is based on heat and moisture exchange between the material being dried (raw products) and heated drying air, which blows on the products. The drying process involves bringing the moisture inside the product to its surface, converting the moisture into steam, and removing steam from the surface of the product. According to this scheme, osmotically bound moisture is removed. Adsorption-bound moisture turns into steam inside the material and moves to the surface in the form of steam. In the pasta drying scheme on Pavan lines, the raw product, as already mentioned, enters the trabatto, which is intended for primary processing (drying) of the product. Trabatto is a carbon steel frame on which a vibration plane drive unit, a heating and ventilation unit and a moist air removal device are installed. The product, leaving the pre-vibration dryer (trabatto), is directed to the pre-dryer (TR 51) using a cup elevator and is evenly distributed there over the surface of the upper level belt. Then the product passes further and gradually fills the belts at all levels, and the direction of movement of the belt changes to the opposite as the product passes through the dryer. The speed variator allows you to set the optimal speed for each pasta format. As the product passes through the dryer, it falls from one level of belt to another; This achieves constant mixing, which prevents gluing and promotes better blowing of the products with air, which is forced into the dryer. At all drying levels, the product is subjected to intensive ventilation. The air is supplied from powerful fans and heated by passing through special heating elements (batteries). The air temperature in the dryer is maintained at 75...80? C, relative humidity - 80...90%. Abundant supply of heat and ventilation allows you to dramatically reduce the moisture content in pasta in 25 - 40 minutes. The product, dried to a moisture content of 18...19%, is loaded into the final dryer (TR 56) using a cup elevator and distributed evenly across the entire width of the conveyor belt. The height of the loading layer varies depending on the format, and the recommended standard height is about 50...60 mm on the first plane (top) and no more than 160...170 mm on the last (bottom). The residence time of the product in the final dryer can reach 5 hours. The structure of the dryer is modular. Each module has a heating battery, a fan unit, electric valves for shutting off hot water and air exhaust devices. The dryer draws in air from the exit of the last plane (lowest) and pushes it out at the pasta inlet onto the first plane (topmost). In this way, it is possible to obtain a product that is not too hot (35...40? C) and almost completely stabilized at the exit from the dryer. The humidity of the product on the upper tier of the dryer is 18...19% and 13...14% on the fifth plane, so it decreases by one percent on each subsequent plane of the dryer. The Tecalit production line uses a “TDU 1800” dryer, which consists of three elements: the upper drying part, the lower drying part and the last level - stabilization, where the temperature reaches 40 - 45? C. The dryer receives the product directly from the trabatto, which is sent to the first level of the upper drying section through a ring elevator and a vibrating screen. The vibrating sieve is the connection between the ring elevator discharge and the dryer loading. The vibrating sieve consists of a vibrating level, which, with the help of two vibrators, allows the distribution and passage of the product. It also includes a manual adjustment that shuts off the pasta feed to the dryer when necessary to prevent excessive moisture from being released from the dryer. In the area where the pasta enters the dryer there is a compressor that collects all the air at the outlet of the loading pipe and transfers it to the fans in the upper part. The product undergoes pre-drying and drying for 5 - 7 hours. During this time, the product is ventilated and heated to evaporate the water. All this happens automatically and the resulting product reaches a humidity of 12.5 - 12%. If on the Pavan lines each tier of the dryer has its own temperature, then on the Tecalit line there is one temperature at all levels. At the moment when the fans are turned on, the pasta is dried, and when it is turned off, it is cooled. Fans operate in hard and soft modes. Hard mode is when the fans accelerate air against the flow of pasta, and soft mode - when in the direction of movement of pasta. Thus, drying ends when the humidity reaches 13.5...14%, so that after cooling before packaging, their humidity is no more than 13%. RELATED ARTICLES Feedback Site Map About the site