WO2021090188A1 - Plant for producing dry pasta - Google Patents

Abstract

Plant (1) for producing dry pasta (P) comprises a kneading device (2) to produce a dough from which said pasta (P) is obtainable, a ventilating apparatus (17) and a dryer (3), in which said kneading device feeds a first extruding device (10) configured for producing long dry pasta, and a second extruding device (12) configured for producing short dry pasta, wherein said dryer (3) comprises a first drying section (4) arranged at a first level and intended for drying long pasta, and a second drying section (5) arranged at a second level placed above said first level, intended for drying short pasta, and wherein said ventilating apparatus (17) comprises a first ventilation section (26), intended for receiving long pasta produced by said first extruding device (10) and arranged at said first level, and a second ventilation section (27) intended for receiving short pasta produced by said second extruding device (12) and arranged at said second level.

Description

PLANT FOR PRODUCING DRY PASTA

[0001] The invention relates to a plant for producing dry pasta, in particular a plant for drying pasta produced with durum wheat semolina, or with soft wheat flour, or with a mixture of durum wheat semolina and soft wheat flour.

[0002] Pasta drying plants are known from the prior art whose purpose is to eliminate progressively from the product part of the initial water content, by administering heat, to lower the degree of humidity of the product. Lowering the degree of humidity means reducing enzyme activity, thus minimizing fermentation.

[0003] Drying can be performed in plants provided with suitable sources of heat that heat a mass of air, which is subsequently sent into contact with the pasta to be treated to heat the pasta so as to evaporate progressively the humidity contained therein.

[0004] There are normally three steps of a hot air drying process: a first pre-drying step, a second drying step proper and a third stabilization step.

[0005] In the first pre-drying step, the pasta coming from a kneader and extruded through an extruding device is in a plastic state, thus with the possibility of being deformed. In this first step, the pasta is heated rapidly at high heat supply so as to reach the maximum obtainable value of the Q/t ratio without damaging the pasta, where Q/t is the quantity of humidity removed from the pasta per unit of weight in the unit of time.

[0006] The pre-drying step can be performed in a continuous pre-drying device in which the pasta moves at a constant speed inside the apparatus and is hit by a continuous hot air flow with a low level of humidity coming from a heat exchanger. The hot air flow causes heating of the pasta that causes the humidity contained in the pasta to evaporate and to be transferred to said air flow.

[0007] The heat transfer to the pasta occurs in two modes: by convection from the hot air flow to the surface of the pasta and by conduction from the surface to the inside of the pasta.

[0008] Also the humidity transfer from the pasta to the hot air flow that flows over the pasta occurs in two different modes: by diffusion from the inner layers of the pasta to the surface and by evaporation from the surface of the pasta to the hot air flow.

[0009] At the end of the pre-drying step, the pasta is no longer in a plastic state but in an elastic state. This means that temperature differences inside the pasta can cause internal tensions that, if they reach high values, can cause permanent deformation and also breaks in the pasta.

[0010] In order to prevent the occurrence of excessive tensions in the mass of the pasta, in the drying step the heat transfer from the hot air flow to the pasta occurs more slowly, so that excessively high temperature gradients are not generated inside the pasta. This means that humidity is removed more slowly from the pasta than in the pre-drying step. If with Qi/t the humidity quantity is indicated that is removed from the pasta per unit of weight in the unit of time during the drying step, this quantity is less than the quantity Q/t removed in the pre-drying step, i.e. Qi/t<Q/t.

[0011] Also the drying step can be performed in a continuous drying device that normally extends in height. The pasta is moved inside the device from top to bottom whilst a hot and dry air flow moves from bottom to top.

[0012] In order to avoid drying defects, it is important for the air speed inside the drying device to be as constant as possible.

[0013] The drying step is considered to be concluded when the residual humidity of the pasta does not exceed 12.5%, which is the maximum humidity value for dry pasta established by law.

[0014] At the end of the drying step, the pasta is subjected to a so-called stabilization step so that the humidity percentage is uniform throughout the entire mass of the pasta so as to prevent existence of zones in the mass of the pasta with residual humidity above said value, even if the total overall residual humidity is not greater than 12.5%.

[0015] In the stabilization step, the pasta is maintained at a temperature above ambient temperature for a set time, at the end of which possible humidity gradients inside the mass of the pasta are zeroed.

[0016] Lastly, the pasta is cooled to ambient temperature to be subsequently packaged. [0017] It should be noted that, when the pasta is still in plastic state, i.e. in the initial step of the drying process that was previously defined as the pre-drying step, the transfer of humidity from the pasta to the hot air flow depends essentially on the conditions inside the drying device, i.e. on the speed, temperature and humidity of the air flow that hits the pasta. On the other hand, when the pasta changes from the plastic state to an elastic state, at the end of the pre-drying step, the transfer of humidity from the pasta to the hot air flow depends essentially on the diffusion of the humidity inside the mass of the pasta. [0018] The diffusion of humidity inside the pasta decreases as drying progresses, which inevitably lengthens drying time.

[0019] Currently, for industrial production of dry pasta with drying of the pasta by hot air, separate production plants are required to be able to produce all the pasta formats present on the market. In particular, three different types of production plant are required, one for the long pasta formats, one for the short pasta formats and one for the special formats. This entails high manufacturing costs for dry pasta production plants and high running costs in addition to requiring large spaces available for arranging the three production plants necessary for producing all the types of pasta requested by the market. [0020] One object of the present invention is to provide a plant for producing dry pasta, obtained from durum wheat semolina, from soft wheat flour, or from mixtures of durum wheat semolina and soft wheat flour, that is able to produce and simultaneously dry long pasta, short pasta and special formats of pasta, eliminating the need to have at one’s disposal a different type of apparatus for each type of pasta, short, long or special pasta. [0021] The object of the invention is reached with a plant for producing dry pasta according to claim 1.

[0022] Owing to the invention, it is possible to produce and dry with hot air long pasta, short pasta, and pasta with special formats, with significant reduction of manufacturing and depreciation costs of the apparatus and a significant reduction of the space necessary for implementing the plant compared with plants for producing long and short dry pasta according to the prior art.

[0023] Further features and advantages of the invention will be clear from the following description of an embodiment of the invention, purely by way of non-limiting example, with reference to the attached drawings, in which:

[0024] Figure 1 is a plan view of an apparatus for producing dry pasta according to the invention;

[0025] Figures 2 is an elevation view of the apparatus of Figure 1, in which, for the sake of clarity, the extruding section of the short or special pasta has been omitted;

[0026] Figures 3 is an elevation view of the apparatus of Figure 1 in which the extruding section of the long pasta has been omitted;

[0027] Figure 4 is an enlarged detail of Figure 2;

[0028] Figure 5 is an enlarged detail of Figure 3; [0029] Figure 6 is a cross section of the apparatus of Figure 1, according to the section line A-A in Figure 1 ;

[0030] Figure 7 is a cross section of the apparatus of Figure 1, according to the section line B-B in Figure 1;

[0031] Figure 8 is an enlarged detail of the plant of Figure 1.

[0032] The food pasta can be indicated below more briefly as pasta.

[0033] In Figures 1 to 8, an apparatus according to the invention is illustrated for producing long pasta, such as for example spaghetti, bucatini, mafalde, candele or any other type of both long pasta, and short pasta, such as for example maccheroni, penne, fusilli, conchiglie and any other type of short pasta.

[0034] With reference to the figures, an apparatus 1 according to the invention comprises a kneading and extruding device 2, that is able to produce both long pasta and short pasta, and a hot air dryer 3, divided into two sections arranged on two levels: a first drying section 4, arranged on a first level, intended for drying long pasta and a second drying section 5, arranged on a second level placed above said first level, intended for drying short pasta.

[0035] The kneading and extruding device 2 comprises a decantation cyclone 6 into which durum wheat semolina or soft wheat flour are delivered. The decantation cyclone 6 feeds a volumetric dosing device 7 that sends the semolina or flour to a vacuum kneader 8 in which the semolina or flour is mixed with water to obtain dough from which the pasta will be obtained. The dough is made by mixing the semolina or flour, which normally has relative humidity comprised between 9% and 14 %, with hot water between 30 and 45°C in sufficient quantity to take the relative humidity of the product to a value comprised between about 28% and about 35%.

[0036] Inside the kneader 8, the water is absorbed completely by the semolina, or by the flour, to obtain the dough from which the pasta will be obtained. Kneading occurs at pressure from 0.2 to 0.5 bar and lasts for a period of about 20 minutes, at the end of which the dough obtained can be sent to a first transferring device 9, for example a first feed screw, which feeds a first extruding device 10, and/or a second transferring device 11, for example a second feed screw, which feeds a second extruding device 12. The first transferring feed screw 9 and the second transferring feed screw 11 can be supplied simultaneously or alternatively. The first extruding device 10 is intended for producing long pasta, whereas the second extruding device 12 is intended for producing short pasta. [0037] The possibility of supplying both the extruding devices or only one of them makes it possible to keep the plant running even if maintenance or repair tasks have to be performed on one of the two long or short pasta production lines.

[0038] In order to produce long pasta, the dough coming from the kneader 8 is sent to the first extruding device 10 by the first transferring feed screw 9. In the first extruding device 10, the dough is pushed at a pressure comprised between about 80 bar and about 110 bar through a first extruder 13 by means of which a curtain of pasta units P (Fig. 2) is formed that are sent to a so-called spreading device 14, in which the pasta units P are trimmed and positioned on support and conveying elements 15, for example in the form of rods or canes, on each of which a plurality of pasta units P is loaded.

[0039] The extruder 13 is interchangeable, depending on the type of long pasta that has to be produced.

[0040] The support and conveying elements 15 are loaded onto a first conveyor device 16 by means of which the support and conveying elements 15 with the pasta units P are conveyed to a ventilating apparatus 17 which is also divided into two sections arranged on two levels: a first ventilation section 26 arranged at a first level, intended for receiving the units of long pasta P, and a second ventilation section 27 arranged at a second level, placed above the first level, intended for receiving units of short pasta. In the first section 26 of the ventilating apparatus 17, the support and conveying elements 15, with the respective pasta units P are loaded on a second conveyor device 18 that conveys the support and conveying elements 15 with the pasta units P through the first section 26 of the ventilating apparatus 17.

[0041] In the ventilating apparatus 17, the pasta units P are subjected to ventilation with air between 35 and 45 °C, by a plurality of first ventilating devices 19, that, by drying slightly the outer part of the pasta, prevent the pasta becoming excessively elongated through the effect of its own weight.

[0042] The first ventilating devices 19 circulate the air both in the first section 26, and in the second section 27 of the ventilating apparatus 17, as can be seen in Figure 6 in which the arrows indicate the path of the air inside the ventilating apparatus 17.

[0043] At the outlet of the ventilating apparatus 17 the support and conveying elements 15 with the respective pasta unit P are transferred on a third conveyor device 20 that introduces the support and conveying elements 15 into the first section 4 of the dryer 3 and conveys the support and conveying elements 15 through said first section 4 in which the pasta units P undergo a dehydration process that reduces the humidity of the pasta to a value comprised between 5% and 12.5%. In this step, the pasta is hit by hot air at a temperature that is variable between 55 °C and 75 °C for a period of time comprised between 3 and 5.5 hours.

[0044] The hot air is sent onto the pasta units P by a plurality of second ventilating devices 21 distributed inside the dryer 3.

[0045] The second ventilating devices 21 circulate the air both in the first section 4 and in the second section 5 of the dryer 3, as can be seen in Figure 7 in which the arrows indicate the path of the air inside the dryer 3.

[0046] At the end of drying, the pasta units P leave the first section 4 of the dryer 3 and are conveyed by a fourth conveyor device 22 in an extracting and cutting device 23 in which the pasta units P are extracted from the support and conveying elements 15 and cut to a preset standard length for packaging, equal to about 260 mm. From the extracting and cutting device 23, the pasta P is then sent to a packaging apparatus (which is not shown). [0047] In order to produce short pasta, the dough coming from the kneader 8 is sent to the second extruding device 12 by the second transferring feed screw 11. In the second extruding device 12, the dough is pushed, at pressure comprised between about 100 bar and about 105 bar, through a second extruder 24, exiting which the dough is cut into a plurality of units of short pasta by a cutting device, which is not shown. The extruder 24 is interchangeable, depending on the type of short pasta that has to be produced.

[0048] The short pasta that is thus produced is sent to a ventilated screen device 25, known as a “multiple sieve”, in which the units of short pasta are hit by a hot air flow at a temperature that is variable between 60° C and 90° C, for a time that is variable between 3 and 5 minutes, in which the units of short pasta are separated from one another and sent to a lifting device 28, for example a bucket lifting device, by means of which the units of short pasta are conveyed to an inlet of the second section 27 of the ventilating device 17 and made to descend by gravity, along a slide 29, on a first conveying element 30, for example a belt conveyor, that conveys the units of short pasta in an advancement direction F, until dropped by gravity onto at least one second conveying element 31, for example a belt conveyor, tilted upwards in said advancement direction F, that conveys the elements of short pasta as far as the entry of the second section 5 of the dryer 3, where the units of short pasta fall onto a first further conveying element 32’ of a plurality of further conveying elements 32, for example belt conveyors, by means of which the units of short pasta are conveyed through the second section 5 of the dryer 3.

[0049] The at least one second conveying element 31 can comprise a plurality of second conveying elements 31 each of which is tilted upwards in the advancement direction F. [0050] Each of the further conveying elements 32 is tilted upwards in said advancement direction F.

[0051] The units of short pasta move from the at least one second conveying element 31 to the first further conveying element 32’ and from each further conveying element 32 to the next by falling by gravity from one conveying element to the next and overturning during the fall.

[0052] This overturning, repeated at each transit from one conveying element to the next, enables the units of short pasta to be dried evenly, preventing lack of drying uniformity between opposite sides of the units of short pasta.

[0053] The units of short pasta, after reaching the outlet end of the second section 5 of the dryer 3, conveyed by a last further conveying element 32” of said plurality of further conveying elements 32, fall on a vibrating frame 33, arranged transversely to the advancement direction F, which conveys the units of short pasta to a chute 34, which transfers the units to a ventilated evacuating conveyor 35, on which the units of short pasta are cooled before being sent to a packaging apparatus (which is not shown).

[0054] Owing to the invention, it is possible to integrate in a single plant two independent production lines that may be used simultaneously or alternatively depending on the production needs and market demand, using a single dryer, a single kneader and a single press with two independent compression units, with related saving in the investment with respect to the purchase of two traditional separate plants and in addition energy saving thanks to the electric supply of a single plant.

[0055] The plant according to the invention has much greater operating efficiency than plants known from the prior art because it requires the use of a smaller number of human resources with consequent optimization of the work and company costs.

[0056] The plant according to the invention, which combines two production lines for producing different types of pasta in a single plant, has overall plan dimensions that are substantially the same as those of a single production line according to the state of the art. This gives the possibility of creating a plant that has the same productive capacity as two separate lines in half space, by reducing accordingly the dimensions of the necessary premises with a simultaneous reduction of the cost of hiring and purchasing the premises. The result is optimization of the spaces and corresponding costs.

[0057] Optimization of the spaces accordingly impacts the use of the available premises so as to be able to double productive capacity because the plant according to the invention has twice the productive capacity for the same overall dimensions compared with known prior art plants.

[0058] It is possible to perform maintenance or repair of one of the two production lines of long pasta or short pasta without having to interrupt operation of the other line, it being possible to exclude one of the two extruding devices 10, 12, keeping the other extruding device operating.

[0059] One of the two extruding devices can also be excluded if there is a need to interrupt production of one of the two, long or short pasta, because of reduced request by the market for this type of pasta.

Claims

1. Plant (1) for producing dry pasta (P) comprising a kneading device (2) to produce a dough from which said pasta (P) is obtainable, a ventilating apparatus (17) and a dryer (3), characterized in that said kneading device feeds a first extruding device (10) configured for producing long pasta, and a second extruding device (12) configured for producing short pasta, in that said dryer (3) comprises a first drying section (4) arranged at a first level and intended for drying long pasta, and a second drying section (5) arranged at a second level placed above said first level, intended for drying short pasta, and in that said ventilating apparatus (17) comprises a first ventilation section (26), intended for receiving long pasta produced by said first extruding device (10) and arranged at said first level, and a second ventilation section (27) intended for receiving short pasta produced by said second extruding device (12) and arranged at said second level.

2. Plant (1) according to claim 1, wherein said kneading device (2) comprises a kneader (8) in which said dough is made, said dough being able to be sent to a first transferring device (9), which feeds said first extruding device (10), and to a second transferring device (11), which feeds said second extruding device (12).

3. Plant according to claim 1, or 2, characterized in that it is configured for feeding both the extruding devices (10, 12), or only the first extruding device (10) or only the second extruding device (12).

4. Plant (1) according to one of the preceding claims, characterized in that it further comprises a plurality of support and conveying elements (15) on each of which a plurality of long pasta units (P) can be arranged.

5. Plant (1) according to claim 4, characterized in that it further comprises a spreading device (14), in which the pasta units (P) produced by the first extruding device (10) are trimmed and positioned on said support and conveying elements (15).

6. Plant (1) according to one of the preceding claims, characterized in that it further comprises a screen device (25) in which the short pasta units produced by the second extruding device (12) are separated from one another.

7. Plant (1) according to claim 5, or 6, characterized in that it further comprises a first conveyor device (16) by means of which said support and conveying elements (15) with the pasta units (P) are conveyed from said spreading device to said first section (26) of said ventilating apparatus (17).

8. Plant (1) according to claim 7, wherein said first section (26) of said ventilating apparatus (17) is provided with a second conveyor device (18), which receives said support and conveying elements (15) with the pasta units (P) from said first conveyor device (16) and conveys said support and conveying elements (15) from said first section (26) as far as the first section (4) of the dryer (3).

9. Plant (1) according to claim 8, wherein said first section (4) of the dryer (3) is provided with a third conveyor device (20) which receives said support and conveying elements (15) with the pasta units (P) from said second conveyor device (18) and conveys the support and conveying elements (15) through said first section (4) of the dryer (3).

10. Plant (1) according to one of claims 5 to 9, characterized in that it further comprises a fourth conveyor device (22) that conveys the support elements (15) with the pasta units (P) from the first section (4) of the dryer (3) to an extracting and cutting device (23) in which the pasta units (P) are extracted from the support and conveying elements (15) and cut to a preset length.

11. Plant (1) according to one of the preceding claims, characterized in that it further comprises a screen device (25) which receives short pasta units produced by said second extruding device (12) and separates the short pasta units from one another.

12. Plant (1) according to claim 11, characterized in that it further comprises a lifting device that transfers said short pasta units from said screening device (25) to said second section (27) of the ventilating apparatus (17).

13. Plant according to one of the preceding claims, wherein said second section (27) is provided with a first conveying element (30) that conveys the short pasta units in an advancement direction (F) until the short pasta units drop by gravity onto at least one second conveying element (31), tilted upwards in said advancement direction

(F).

14. Plant (1) according to claim 13, wherein said second section (5) of the dryer (3) is provided with a plurality of further conveying elements (32), each of which is tilted upwards in the advancement direction (F), wherein a first further conveying element (32’) of said plurality of further conveying elements receives the short pasta units from said at least one second conveying element (31).

15. Plant (1) according to one of the preceding claims, wherein said second section (5) of the dryer (3) comprises a vibrating frame (33) which receives the short pasta units from a last further conveying element (32”) of said plurality of further conveying elements (32) and conveys the short pasta units to a chute (34) that transfers the short pasta units to an evacuating conveyor (35), said vibrating frame being arranged transversely to said advancement direction (F).