WO2020230018A1

WO2020230018A1 - Die, apparatus and method for extruding food products

Info

Publication number: WO2020230018A1
Application number: PCT/IB2020/054475
Authority: WO
Inventors: Daniele FOTO
Original assignee: SPAGNUOLO, Alex
Priority date: 2019-05-14
Filing date: 2020-05-12
Publication date: 2020-11-19
Also published as: EP3968773A1

Abstract

Die (1) for extruding food products comprising a main body (100) having an inlet surface (1A) for the inlet of a starting food product, and an outlet surface (IB) for the exit of an extruded food product (109). The main body (100) provides an extrusion group (110) comprising a predetermined number of tubular extrusion ducts (101) distributed on a plurality of parallel lines (116a,116b). The main body (100) and the plurality of tubular extrusion ducts (101) define at least a thermoregulation chamber (120). The main body (100) provides at least an inlet hole (103a) in communication with the, or each, thermoregulation chamber (120), in such a way that through the, or each, inlet hole (103a) a flow of a thermoregulating fluid can be introduced into the, or each, thermoregulation chamber (120) and is able to hit a tubular extrusion duct (101) arranged on the first line (116a) and at least a tubular extrusion duct (101) arranged on the second line (116b), in order to adjust the temperature of the plurality of tubular extrusion ducts (101).

Description

TITLE

DIE, APPARATUS AND METHOD FOR EXTRUDING FOOD PRODUCTS

DESCRIPTION

Field of the invention The present invention relates to the field of the dies for producing food products such as pasta and snack.

In particular, the invention relates to a die for extruding food products for obtaining extruded food products, such as pasta and snack.

The invention relates, furthermore, to an apparatus and a method for extruding food products that use such die .

Background of the invention

Extrusion processes are known that use presses, which push a dough against a die, and cutting tools for cutting the extruded dough according to a desired size forming food products such as pasta and snack.

The dies having, normally, a circular or rectangular shape, provide filters, which homogenize the dough, and inserts, which provides the desired shape to the product.

The prior art dies have many critical issues, which need frequent maintenance and replacement operations to obtain products of good quality.

Normally, the dies and the relative components are made of materials having a good thermal conductivity. In fact, it is desirable to maintain the temperature of the die constant and to effectively dissipate the heat generated by friction during the extrusion operation, for the transformation of the mechanical energy applied to the press .

In particular, the excessive heat generated by the friction between the dough, the filters and the die, causes the following drawbacks:

an uncontrolled increasing of the temperature, which causes thermal deformations, which can also cause the die and the extruding inserts to break;

the degradation of the protein contents caused by the excessive heat;

an excessive reduction of the viscosity of the doughs used passing through the die, and, therefore, a inhomogeneous quality of the extruded product, also called "grain", due to the difficult to maintain the desired shape, with impacts on the entire production line, above all, in the packaging step, where, notwithstanding the dosing machines can make packages of equal mass, the content of "grains" is less or higher than the desired content.

In order to avoid the aforementioned drawbacks, generally, the dies, which get overheated, are dismounted from the machine and replaced with other dies. The dismounted dies are cleaned and cooled before being used again .

However, after a certain number of cleaning and cooling cycles, the dies, and the relative inserts, are no more able to produce a uniform product. Furthermore, each disassembly and replacement operation implies to stop the production and to have a non-negligible loss of dough. High costs for maintenance and replacement result.

On the other side, a drawback opposite to the previous one, also this found in the prior art dies, is that, if the same dies are used in geographic areas with low temperatures, also less than -15°C, it is felt the need of heating the dies, in particular before mounting the same in the machine, in order to avoid that, due to the low temperatures, the viscosity of the dough remains to a value higher than an upper threshold value that would cause the extrusion operation to be carried out very slowly and difficultly. In particular, if the extrusion machine is installed within a big industrial warehouse and, therefore, difficult to heat above 5°C, even if the dies were preliminary heated by dipping the same into a hot water bath, the extrusion step would be, anyway, difficult to carry out and, therefore, it would be not possible to have a high productivity.

Another drawback of the prior art dies, is that at the more internal extrusion, or drawing, ducts, a greater friction is produced owing to the greater push due to the law of sliding of a viscous fluid in laminar motion. Therefore, at these extrusion ducts a higher heat is generated and, therefore, a change in the viscosity occurs with respect to the other lines. This causes a non- negligible difference in the extrusion speed, which can compromise the product quality.

In the machines that use the prior art dies, in order to try to overcome the aforementioned technical problems, compensation plates are used for reducing the section of the inlet hole. However, this solution is not able to solve the aforementioned technical problem.

Examples of prior art dies with the aforementioned drawbacks are described in US2017/202261 , EP1275483 and

JPS60199373. Summary of the invention

It is an object of the present invention to provide a die for extruding food products, in particular pasta and snack, that is able to solve the aforementioned drawbacks of the prior art dies.

It is also an object of the present invention to provide a die which allows to reduce thermal deformations, in such a way to reduce the wear, and the possibility that fragments of the die, as well as, of the relative extruding inserts can be produced.

It is also an object of the invention to provide a die for food products that allows to reduce the degradation of the protein contents that can be caused by a too high heat .

It is a further object of the invention to provide a die for food products that is able to avoid an excessive reduction of the viscosity of the doughs used in the passageway can occur through the die and, therefore, an inhomogeneous quality of the extruded product.

It is, furthermore, an object of the invention to provide an apparatus for extruding food products which allows to adjust the temperature of the, or each, die of which is equipped in a very accurate way.

It is still another object of the present invention to provide an apparatus for extruding food products that allows to reduce the breaks of the machine to replace the dies and therefore to reduce the loss of productivity.

It is a further object of the present invention to provide an apparatus for extruding food products that allows, if necessary, to reduce the viscosity of the dough in such a way to increase the productivity of the machine. These and other objects are achieved by a die for extruding food products, in particular pasta and snack, comprising a main body having an inlet surface for the inlet of a starting food product, and an outlet surface for the exit of an extruded food product, said main body being provided of an extrusion group comprising a predetermined number of tubular extrusion ducts, each of which having an internal surface and an external surface, said extrusion group comprising at least a first plurality of tubular extrusion ducts arranged along a first line, and at least a second plurality of tubular extrusion ducts arranged along a second line parallel to the first line, whose main characteristic of the aforementioned die is that the main body and the extrusion group are configured in such a way to define at least a thermoregulation chamber, said main body being provided with at least an inlet hole in communication with said, or each, thermoregulation chamber, such that through said, or each, inlet hole, a flow of a thermoregulating fluid can be introduced into said, or each, thermoregulation chamber, to adjust the temperature of said plurality of tubular extrusion ducts, and that the main body and the extrusion group are configured in such a way that the external surface of at least a tubular extrusion duct of said first plurality is in hydraulic communication with the external surface of at least a tubular extrusion duct of said second plurality.

According to another aspect of the invention, an apparatus for extruding food products comprises:

- a die for extruding food products according to the invention; - a cutting device configured to cut said extruded product exiting said outlet surface, said cutting device comprising a support shaft and a cutting element movable with respect to said support shaft; whose main characteristic is that said support shaft provides a longitudinal cavity through which said flow of said thermoregulating fluid is arranged to be fed into said thermoregulation chamber through the, or each, inlet hole .

According to a further aspect of the invention, a method for extruding food products comprises the steps of:

- arranging a die for extruding food products providing a main body, which has an inlet surface for the inlet of a starting food product, and an outlet surface for the exit of an extruded food product, said main body being provided with an extrusion group comprising a predetermined number of tubular extrusion ducts each of which having an internal surface and an external surface, said extrusion group comprising at least a first plurality of tubular extrusion ducts arranged along a first line and at least a second plurality of tubular extrusion ducts arranged along a second line parallel to the first line, and at least an inlet hole, and wherein said main body and said extrusion group are configured in such a way to define at least a thermoregulation chamber in communication with said, or each, inlet hole;

- introducing a starting food product into said die through said inlet surface;

- extruding the aforementioned starting food product through said die thus obtaining an extruded food product exiting said outlet surface;

- generating a flow of a thermoregulating fluid;

- introducing said flow of said thermoregulating fluid into said, or each, thermoregulation chamber through said, or each, inlet hole, said thermoregulating fluid entering into contact with at least an external surface of a tubular extrusion duct of said first plurality and with the external surface of at least a duct of said second plurality in hydraulic communication with the same, in such a way to adjust the temperature of said plurality of tubular extrusion ducts.

Further features of the present invention and related embodiments are set out in the dependent claims.

Brief description of the drawings

The invention will be now illustrated with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

- Fig. 1 diagrammatically shows a perspective view of a first embodiment of a die for extruding food products, according to the invention;

- Fig. 2A diagrammatically shows a plan view of a die for extruding pasta according to the invention;

- Fig. 2B shows a section view according to the arrows K-K of the die of figure 2A;

- Fig. 2C shows an enlargement of figure 2B;

- Fig. 3 shows an embodiment of the die alternative to that of figure 2A;

- Fig. 4A diagrammatically shows a side elevation view of the die of figure 3;

- Fig. 4B shows a cross-section of the die of figure 4A according to the arrows F-F;

- Fig. 4C shows an enlargement of a portion of figure 4B;

- Fig. 5 shows another alternative embodiment according to the invention for the die of figure 2A;

- Fig. 6A shows a plan view of the die of figure 5 in order to highlight some characteristics of the same;

- Fig. 6B shows a section according to the arrows A-A of the die of figure 6A;

- Fig. 7 shows a perspective view of an alternative embodiment of the die shown in figure 1;

- Fig. 8A shows a side elevation view of the die of figure 7;

- Fig. 8B shows a section according to the arrows A-A of the die of figure 8A;

- Fig. 8C shows a section according to the arrows B-B of the die of figure 8A;

- Fig. 9A diagrammatically shows a plan view of an alternative embodiment of the die of figure 8A;

- Fig. 9B shows a section according to the arrows G-G of the die of figure 9A;

- Fig. 10A shows a plan view of another alternative embodiment of the die of figure 7;

- Fig. 10B diagrammatically shows a section according to the arrows H-H of the die of figure 10A;

- Fig. IOC diagrammatically shows an enlargement of a portion of figure 10B;

- Fig. 11A shows a plan view of still another alternative embodiment of the die according to the invention;

- Fig. 11B shows the die of figure 11A according to the arrows M-M;

- Fig. 12A shows a plan view of another alternative embodiment of the die according to the invention;

- Fig. 12B shows the die of figure 12A according to the arrows D-D;

- Fig. 13 shows a perspective view in a disassembled configuration of another alternative embodiment of the die according to the invention;

- Fig. 14 diagrammatically shows an exploded perspective view of another alternative embodiment of the die according to the invention;

- Fig. 15A shows a plan view of another alternative embodiment of the die according to the invention;

- Fig. 15B shows the die of figure 15A in a section according to the arrows E-E;

- Fig. 16A shows a plan view of another alternative embodiment of the die according to the present invention;

- Fig. 16B shows the die of figure 16A according to the arrows F-F;

- Figures 17A and 17B diagrammatically show further alternative embodiments of the die according to the invention;

- Fig. 18 diagrammatically shows a perspective side elevation view of an apparatus for extruding food products according to the invention;

- Fig. 19 diagrammatically shows a perspective side elevation view of a first alternative embodiment of the apparatus of figure 18; - Fig. 20 diagrammatically shows a longitudinal section of another embodiment of the apparatus of figure 18;

- Fig. 21 diagrammatically shows the alternative embodiment of the apparatus of figure 20 in a perspective view with a portion that has been removed to highlight some characteristics;

- Fig. 22 diagrammatically shows still another alternative embodiment of the apparatus of figure 20 according to the invention.

Detailed description of some exemplary embodiments of the invention

The die 1, according to the present invention, provides many embodiments diagrammatically shown in the figures from 1 to 22. In particular, with reference to the figures from 1 to 6B, from 11A to 12B, and from 14 to 22, the die 1, according to the invention, for producing food products, such as pasta and snack, can have a circular cross-section. In some alternative embodiments according to the invention, instead, as diagrammatically shown in the figures from 7 to IOC and 13, the die 1 can have a rectangular cross-section.

In particular, with reference, for example, to figure 1, the die 1 provides a main body 100, for example made of brass, having an inlet surface 1A for the inlet of a starting food product, in particular a dough, and an outlet surface IB for the exit of an extruded food product 109, e.g. pasta, or snack. More in particular, the main body 100 provides an extrusion group 110 comprising a predetermined number of tubular extrusion ducts 101. In particular, each tubular extrusion duct 101 comprises an internal surface 101a, through which, during operative conditions, the food product to be extruded passes through, and an external surface 101b. More precisely, with reference to figure 1, the extrusion group 110 comprises at least a first plurality 115a of tubular extrusion ducts 101 arranged along a first line 116a, and at least a second plurality 115b of tubular extrusion ducts 101 arranged along a second line 116b parallel to the first line 116a.

In the case shown in figure 1, the die 1 has a circular cross-section, therefore, the lines 116a and 116b are 2 circumferences. More precisely, in the case of die 1 having a circular cross-section, the lines 116a and 116b are two concentric circumferences of different diameters. Instead, in the case of die 1 having a rectangular cross- section, as for example the die 1 of figure 7, the lines 116a and 116b are rectilinear lines. In both the cases, anyway, the lines 116a and 116b are parallel with each other .

Advantageously, the main body 100 and the extrusion group 110 are configured in such a way to define at least a thermoregulation chamber 120. The main body 100 is, furthermore, provided with at least an inlet hole 103a in communication with the thermoregulation chamber 120. For example, as shown in figure 1, the inlet hole 103 can be positioned at the centre C of die 1. More precisely, through the, or each, inlet hole 103a a flow of a thermoregulating fluid is introduced into the, or each, thermoregulation chamber 120, in such a way to adjust the temperature of the tubular extrusion ducts 101. Advantageously, the main body 100 and the extrusion group 110 are configured in such a way that the external surface 101b of the tubular extrusion ducts 101 that are arranged on the same line are arranged in hydraulic communication with each other.

In particular, according to the present invention, the, or each, thermoregulation chamber 120 of at least a tubular extrusion duct 101 of the first plurality 115a, i.e. arranged on the first line 116a, can be in hydraulic communication with the external surface 101b of at least a tubular extrusion duct 101 of the second plurality 115b, i.e. positioned on the second line 116b. In particular, the external surface 101b of at least a tubular extrusion duct 101 of the first plurality 115a can be in hydraulic communication with the external surface 101b of at least a tubular extrusion duct 101 of the second plurality 115b through the, or each, thermoregulation chamber 120.

As diagrammatically shown in the figures from 2A to 2C, the extrusion group 110 can comprise at least a third plurality 115c of tubular extrusion ducts 101 distributed along a third line 116c parallel to the first and the second lines 116a and 116b. In particular, the external surface 101b of at least a tubular extrusion duct 101 is, advantageously, in hydraulic communication with the external surface 101b of at least a tubular extrusion duct of the second plurality 116b and/or in hydraulic communication with the external surface 101b of at least a duct of the first plurality 116a.

Still with reference to figure 2A, the main body 100 can be provided with a plurality of housing holes 102. Each of these is arranged to house, in use, a respective tubular extrusion duct 101 (figures 2B and 2C) . More precisely, the tubular extrusion ducts 101 can be arranged to be introduced, by an axial sliding, into respective housing holes 102 from a first side 1A of the die. More in particular, the housing holes 102 can have, at least for a determined length, a cross-section si greater than the cross-section of the respective tubular extrusion ducts 101 that, in operative conditions, are housed within them. In this way, between each tubular extrusion duct 101 and the respective housing hole 102 a thermoregulation chamber 120 is defined, in particular having an annular shape, which permits to control the temperature of the duct same. In this case, therefore, the die 1 has a plurality of thermoregulation chambers 120, each of which associated to a respective tubular extrusion duct 101.

Still with reference to the embodiment of figure 2A, furthermore, the aforementioned main body 100 can be, advantageously, provided with at least an inlet hole 103a, in the example of figure 2A a plurality of inlet holes 103a, in communication with the aforementioned plurality of thermoregulation chambers 120. More precisely, as anticipated above, through the inlet holes 103a, a flow of a thermoregulating fluid having a predetermined temperature T* can be introduced into the plurality of thermoregulation chambers 120 and, therefore, it is possible to control the temperatures of the tubular extrusion ducts 101. More in particular, the thermoregulating fluid can be a cooling fluid having a temperature Tb less than the temperature of the tubular extrusion ducts 101, in order to cool the tubular extrusion ducts 101. In particular, the aforementioned temperature Tb can be set between 0 °C and 40 °C. Alternatively, the thermoregulating fluid can be a heating fluid, that means a fluid having a temperature Ta higher than the temperature of the tubular extrusion ducts 101, in such a way to heat the tubular extrusion ducts 101. In particular, the aforementioned temperature Ta can be set between 50 °C and 200 °C, advantageously set between 50 °C and 100 °C, in particular for extruding a precooked dough, in such a way to heat the tubular extrusion ducts 101.

In general, depending on the temperature of the environment where the die 1, according to the invention, is used, it is possible to use for the thermoregulating fluid a cooling fluid, or a heating fluid, in such a way to cool, or heat the tubular extrusion ducts 101 up to reach a predetermined starting temperature. The adjustment of the temperature of the tubular extrusion ducts 101 allows, depending on the purpose, to remove heat from the ducts 101 if these are subject, in particular owing to the frictions generated during the extrusion step, to an overheating, which could compromise the correct functioning, or reduce the viscosity of the dough, to assist the extrusion step of the same and, therefore, to increase the productivity of the machine on which the die 1 is mounted.

However, it is also provided that, in a first working step, i.e. before extruding the dough, a heating fluid, which has a temperature advantageously set between 50 °C and 80 °C, is used, and that, then, during the extrusion step, a cooling fluid, which has a temperature for example set between 25 °C and 40 °C, is used.

In an alternative embodiment according to the invention, the main body 100 can be provided with only an inlet hole 103a (see for example figure 1) through which the flow of thermoregulating fluid circulates through the thermoregulation chambers 120, or through a plurality of holes 103a (figures 2A and 7) . In particular, the flow of the thermoregulating fluid can be generated by a fan 300. Alternatively, a pneumatic, or hydraulic, plant, not shown in the figures for simplicity, can be provided through which the thermoregulating fluid can be generated and introduced into the, or each, thermoregulation chamber 120, through the, or each, inlet hole 103a.

In particular, a pumping device, not shown in the figures for simplicity, can be provided arranged to generate the aforementioned flow of the aforementioned thermoregulating fluid. More in particular, the aforementioned pumping device can be connected with the aforementioned inlet hole 103a, in such a way to feed the thermoregulating fluid into the thermoregulation chambers 120.

The main body 100 can be, advantageously, provided with at least an outlet hole 103b, through which the thermoregulating fluid is discharged, after having cooled, or heated, the tubular extrusion ducts 101 at the, or each, thermoregulation chamber 120.

More precisely, the thermoregulation chamber 120, during the extrusion of the dough for producing pasta, is fed with a cooling fluid, in such a way that the same can act as cooling chamber allowing to the heat generated within the tubular extrusion duct 101 to be uniformly dissipated and to have a continuous heat exchange.

As shown in detail in figure 2C, the main body 100 can be, furthermore, provided with one, or more, passageways 104, or groove, arranged to connect the, or each, inlet hole 103a and the, or each, housing hole 102. More precisely, the aforementioned passageways 104 can be made at the aforementioned main body 100 at each housing hole 102, or at least a part of the same. Therefore, the, or each, passageway 104 connects at least a part of the thermoregulation chambers 120 of the die 1. In this way, in operative conditions, it is possible to have a substantially homogeneous temperature of the different tubular extrusion ducts 101. This, besides of assuring that an extruded food product of high quality is obtained, allows also to avoid drawbacks such as deformation, or cracks, in the main body 100 of the die 1, caused by the thermal stresses that would be generated by great differences of temperature among the ducts.

According to an embodiment, the main body 100 and the tubular extrusion ducts 101 can be configured to define a plurality of thermoregulation chambers 120. More in particular, at least a part of the aforementioned plurality of thermoregulation chambers 120 can be in communication with each other. In a particular embodiment, all the thermoregulation chambers 120 of the main body 100 are in communication with each other.

In particular, in the main body 100 further ducts, not shown in the figures for simplicity, can be present.

With reference to the figures 2B and 2C, each housing hole 102 can be provided with a stop abutment surface 105 to stop the sliding of the tubular extrusion duct 101 introduced from the side 1A of figure 1. In particular, the stop abutment surface 105 can be obtained by a particular geometry of the housing hole 102 that provides a first portion 102a arranged to house the tubular extrusion duct 101, and a second portion 102b having a cross-section smaller than the cross-section of the first portion 102a, in such a way to define a stop abutment surface 105 for the tubular extrusion duct 101 arranged to be introduced by sliding into the respective housing hole 102.

Furthermore, each housing hole 102 can be also provided with a second stop abutment surface 106 to stop the sliding of any extruding insert 107 arranged to be inserted into the housing hole 102 of the tubular extrusion ducts 101 (see figures 2C, 6B, 8B) . This solution allows, in particular, to remove the extruding inserts 107, to clean, or replace, the same, without disassembling the die 1.

In particular, the second stop abutment surface 106 is positioned downstream of the stop abutment surface 105 with respect to the introduction direction of extruding insert 107. In particular, the second stop abutment surface 106 can be obtained by a third portion 102c of the housing hole 102 arranged to house an extruding insert 107 having a cross-section smaller than the cross-section of the second portion 102b.

In figure 3 a perspective view from side IB, opposite to side 1A, of a die 1 having a circular cross-section, is diagrammatically shown. In this case, some housing holes 102 of the main body 100 are shown provided with the aforementioned extruding inserts 107, which produce the extrusion of the extruded food product 109, in particular "grains" of food products. Furthermore, in the embodiment of figure 3, a plurality of inlet holes 103a is shown, each of which positioned between two following housing holes 102.

Still as shown in figure 3, the aforementioned flow of thermoregulating fluid can be generated by an external fan 300, for example of the type that is commonly used in the pressing plants in order to obtain a pre-drying of the extruded products arranged to direct a flow of hot air, or cool air, on the die 1.

As shown in detail in the figures from 4A to 4C, each inlet hole 103a can be made in the main body 100 from the outside to the inside, and in such a way to be in communication with the passageways 104 connecting each thermoregulation chamber 120 with the inlet holes 103a, allowing the flow of thermoregulating fluid to cool, or heat, the tubular extrusion ducts 101, depending on that the same is a cooling fluid, or a heating fluid. Therefore, in this case, the flow of thermoregulating fluid that is introduced through the inlet holes 103a, passes through the passageways 104 and reaches the thermoregulation chambers 120 where the exchange of heat between the tubular extrusion duct 101 and the cooler, or hotter, flow of air, is such to maintain substantially constant the temperature on the tubular extrusion duct 101.

Figure 5 diagrammatically shows another alternative embodiment of the die 1 having a circular cross-section, according to the invention. More precisely in the alternative embodiment of figure 5, the die 1 can be advantageously, cooled, or heated, by a flow of compressed air generated by a compressor, not shown in the figures for simplicity.

As shown in detail in the figures 6A and 6B, the die 1 can be associated to a closing element, or lid 200, arranged to engage, for example in a removably way, to the main body 100. The closing element 200 can be provided with an inlet hole 103a for the inlet of the flow of thermoregulating fluid, for example a flow of compressed air, into the main body 100 (see figure 6B) . As described above, the flow of the thermoregulating fluid can exit the main body 100, through one, or more, outlet holes 103b, after having cooled, or heated, the tubular extrusion ducts 101 at the thermoregulation chambers 120.

With reference, in particular, to figure 6B which is a half-section according to the arrows A-A of the die of figure 6A, the flow of compressed air enters through the main hole 103a made on lid 200, then, goes towards the thermoregulation holes 108b through connecting channels 108a made in the main body 100. From the thermoregulation holes 108b, the thermoregulating fluid reaches the thermoregulation chambers 120 through the passageways 104. The outlet holes 103b has the function to discharge the hot air from the die IB. Analogously to the embodiment shown in figures 2B and 2C stop abutment surfaces 106 are provided for introducing the extruding inserts 107 if any, and a stop abutment surface 105 for introducing the tubular extrusion duct 101.

The figures from 7 to IOC diagrammatically show some alternative embodiments of the die 1, according to the invention, that is substantially prismatic shaped and with a rectangular cross-section. Analogously to the embodiments of the die 1 shown having a circular cross- section, described above with reference to the figures from 1 to 6B, also in this case, the main body 100 provides an extrusion group 110 comprising a predetermined number of tubular extrusion ducts 101 arranged along at least a first line 116a and a second line 116B parallel to the first line.

In general, the number of tubular extrusion ducts 101 of the extrusion group 110 depends mainly on the diameter of the die. In particular, the extrusion group 110 comprises, preferably, a number Nd of tubular extrusion ducts 101 greater than, or equal to 20, i.e. Nd³20. More in particular, the extrusion group 110 can provide a number Nd of tubular extrusion ducts 101 set between 20 and 300, advantageously between 20 and 80, preferably between 40 and 80, for example between 50 and 70.

In particular, each of the first and the at least a second plurality 115a, and 115b, of tubular extrusion ducts 101 comprises at least 10 tubular extrusion ducts 101.

Also the prismatic shaped die 1 is, furthermore, provided with at least a thermoregulation chamber 120 and at least an inlet hole 103a (figure 10B) , or a plurality of inlet holes 103a (figure 7) .

The main body 100, also in this case, can be provided with one, or more, outlet holes 103b through which the flow of thermoregulating fluid is discharged from the die 1 after having cooled, or heated, the tubular extrusion ducts 101. In particular, also in the case of die 1 having a rectangular cross-section, can be, advantageously, provided a stop abutment surface 105 for the tubular extrusion ducts 101 (see figures 8B and 8C) . Preferably, the die 1 can, also in this case, provide a stop abutment surface 106 for the extruding inserts 107 having the same function of those described above with reference to figure 3.

Furthermore, the main body 100, also in this case, can be provided with passageways 104 to connect the inlet holes 103a to the, or each, thermoregulation chamber 120 (see figure 9B) . Also in this case, therefore, a pumping device, not shown in the figures for simplicity, can be connected with the die 1 at one, or more, inlet holes 103a, in such a way that a flow of thermoregulating fluid can flow through the passageways 104 into the thermoregulation chambers 120 to cool, or heat, the tubular extrusion ducts 101 up to reach the, or each, outlet hole 103b through which the flow of thermoregulating fluid is discharged from the main body 100.

In the embodiments diagrammatically shown, respectively, in the figures 9B and 12B, for a die 1 having a rectangular cross-section, and for a die having a circular cross-section, the passageways 104 can be configured in such a way that each thermoregulation chamber 120 associated to a tubular extrusion duct 101 is in hydraulic communication with the thermoregulation chamber 120 of the tubular extrusion duct 101 adjacent to it, and positioned both along the same line 116a, or 116b, or 116c, and along a line 116b, or 116c parallel to the same .

In the figures 13 and 14 an exploded view is diagrammatically shown of another alternative embodiment according to the invention, respectively, of a die 1 having a rectangular cross-section, and of a die 1 having a circular cross-section. In particular, in this case, the main body 100 comprises a first portion 100a, and at least a second portion 100b, positioned at the opposite sides with respect to the plurality of tubular extrusion ducts 101. More in particular, each portion 100a and 100b of the main body 100 has a respective plurality of housing holes 102a and 102b. More in detail, each tubular extrusion duct 101 is interposed, in use, between a housing hole 102a of the first portion 100a arranged to house a portion 101' of the tubular extrusion duct 101, and a respective housing hole 102b of the second portion 100b arranged to house a portion 101" of the same tubular extrusion duct 101.

At least one of the two portions, for example the portion 100b, provides at least an inlet hole 103a through which the flow of a thermoregulating fluid is arranged to be introduced into the thermoregulation chamber 120.

In the embodiment of figures 15A and 15B, the same portion 100b provides both an inlet hole 103a and at least an outlet hole 103b, in the case shown in the figures a plurality of outlet holes 103b, through which the flow of the thermoregulating fluid is arranged to be discharged from the main body 100 after having passed through the thermoregulation chamber 120.

More precisely, according to the embodiment shown in the figures from 13 to 16B, the main body 100, provides furthermore, a third portion 100c, in particular having an annular shape, if the die has a circular geometry, or a rectangular shape, if the die has a rectangular geometry, interposed between the first and the second portions 100a and 100b in such a way to increase the stiffness of the die 1. In the figures 15A and 15B another embodiment is shown similar to that of figures 13 and 14. In this case the tubular extrusion ducts 101 of the extrusion group 110 are distributed on a first line 116a, a second line 116b, and a third line 116c parallel to each other, as they are 3 concentric circumferences having different diameters. With reference, in particular, to figure 14B, the housing holes 102a, or 102b, of one of the two portions 100a, or 100b, of the main body 100, for example the housing holes 102b of the second portion 100b, can be, advantageously, provided with a first stop abutment surface 105 to stop the sliding of a tubular extrusion duct 101 arranged within the same, and, if present, a second stop abutment surface 106 to stop the sliding of an extruding insert 107 arranged to be housed within the same housing hole 102. In figure 14B the extruding insert 107 and the tubular extrusion duct 101 are not depicted in order to show in detail the housing holes 102.

The further alternative embodiment shown in the figures 16A and 16B is very similar to the embodiment described above with reference to the figures 15A and 15B, but the extrusion group 110 provides, in this case, a greater number of tubular extrusion ducts 101. More precisely, in this case, the tubular extrusion ducts 101 comprise a first, a second, a third, and a fourth plurality of tubular extrusion ducts 115a-115d, respectively, distributed on a first, a second, a third and a fourth line 116a-116d parallel to each other. More precisely, in the figures 16A and 16B the tubular extrusion ducts 101 positioned along the second line 116b are associated to respective extruding inserts 107. As shown in detail in figure 16B, also in this case, stop abutment surfaces 106 for the extruding inserts 107 and/or stop abutment surfaces 105 for the tubular extrusion ducts 101 can be provided.

As diagrammatically shown in figure 15A, the angular distance oil, a2 , ..., ai , ...an, between the tubular extrusion ducts 101 of the same line 116a, 116b, ..., 116i, ...116n, where

116i is i-th line and 116n is the n-th and last line of the extrusion group 110 of the die 1, can be substantially constant. For example, the angular distance oil between two tubular extrusion ducts 101, which follow one another along the first line 116a, can be comprised between 9° and 13°, the angular distance a2 between two tubular extrusion ducts 101, which follow one another along the second line 116b can be set between 10° and 18°. In particular, the angular distance a3, between two tubular extrusion ducts 101, which follow one another on the third line 116c can be set between 18° and 22°. In this way, the product extruded at the most external tubular extrusion ducts 101, therefore, with the greater axial radius, has a length that is equal to the length of the product produced at the most internal tubular extrusion ducts 101, i.e. with the smaller axial radius. More in particular, the angular distance ai between the tubular extrusion ducts 101 of the i-th line 116i, of the extrusion group 110 is constant. Advantageously, the difference between the angular distances ai and ai+ 1 of two following lines 116i and 116i+l of tubular extrusion ducts 101 of the extrusion group 110, in general the i-th and the i+ l-th lines, is constant within a predetermined tolerance limit, for example 6°. In particular, the distance ki between two following tubular extrusion ducts 101 of the i-th line can be set between 5 mm and 20 mm, advantageously between 5 mm and 15 mm, preferably between 6 mm and 10 mm, for example between 6 mm and 8 mm. It should be clarified that with "distance", in this case, it is to be intended the distance between the two lines tangent to the external surfaces of two following tubular extrusion ducts at the closest points of the same.

In general, if n is the total number of the lines 116 of the extrusion group 110, still with reference to figure 15A, the angular distance i with i comprised between 1 and n, between two tubular extrusion ducts 101 of the same line 116i can be, advantageously, computed by the following expression: i=360 · (0i+ki ) /2nri , where 0i is the diameter of the tubular extrusion duct 101, ki is the distance, in particular the minimum distance, between two tubular extrusion ducts 101 of the same line, and ri is the radius of the circumference of the i-th line 116i. The condition to be verified is, anyway, that ni=(360/ i) is an integer number, where ni is the number of tubular extrusion ducts 101 of the i-th line 116i.

According to another aspect of the invention diagrammatically shown in figure 17, a die 1 can be associated to at least a temperature sensor 80 arranged to detect the temperature within the thermoregulation chamber 120. For example, the, or each, temperature sensor 80 can be housed within a respective seat 81 made in the lateral wall of the main body 100. Advantageously, the, or each, temperature sensor 80 can be operatively connected to a control unit 300 to which is arranged to transmit the detected temperature data. The control unit 300 can be configured to compare the aforementioned temperature data received by, or each, temperature sensor 80 and to adjust the flow of thermoregulating fluid fed to the thermoregulation chamber 120, acting on a unit for adjusting the flow 350. In particular, the unit for adjusting the flow 350 can comprise a pushing device 354, for example a pump, or a fan. More in particular, the control unit 300 can be configured to increase, or decrease, the electric power supplied to the motor of the pushing device 354 in such a way to increase, or decrease, the flow of thermoregulating fluid depending on that the detected temperature is less, or greater, than a predetermined threshold value. The unit for adjusting the flow 350 can, furthermore, comprise at least a valve, in particular an electro-valve, and the control unit 300 can be configured to open more, or less, the valve, not shown in the figure for simplicity, depending on that the detected temperature is less, or greater, than the aforementioned predetermined threshold value.

As diagrammatically shown in figure 17B, the control unit 300 can be, furthermore, configured to adjust the thermal power Pt supplied to the flow of thermoregulating fluid at a heat exchanger 355, positioned upstream of the die 1, for example between the pushing device 354 and the die 1. In a possible embodiment, the heat exchanger 355 can be provided with at least an electric resistance 356. In this case, therefore, the control unit can be arranged to increase, or decrease, the electric current supplied to the, or each, electric resistance 356, of the heat exchanger 355 to provide more, or less, thermal power Pt to the flow of thermoregulating fluid, which passes through the heat exchanger 355 same.

With reference to the figures from 18 to 21, an apparatus 50 for extruding food products, according to the invention, comprises a die 1, according to one of the embodiments described with reference from figure 1 to figure 16B, and a cutting device 150 configured to move with respect to said die 1 in such a way to cut the extruded product 109 exiting the outlet surface IB. More precisely, the cutting device 150 is positioned on the side of the outlet surface IB and comprises a support shaft 155 and a cutting element 156, in particular a knife, movable with respect to the support shaft 155. In particular, the cutting element 156 can be integral to a sleeve 159 mounted on the support shaft 155 in such a way to rotate about a rotation axis 160 (see figures 18-21) . However, according to an alternative embodiment, not shown in the figures for simplicity, it is also provided that the cutting element 156 can be arranged to slide with respect to the support shaft 155, for example, operated by an actuator. More in detail, the support shaft 155 provides a longitudinal cavity 157 through which the flow of the thermoregulating fluid is arranged to be fed into the thermoregulation chamber 120 through the, or each inlet hole 103a. As shown, for example, in figure 19, the aforementioned longitudinal cavity 157 is configured to house at least a tubular element 170a in communication with the thermoregulation chamber 120. For example, through the, or each tubular element 170a it is possible to feed the flow of the thermoregulating fluid into the thermoregulation chamber 120 through which the flow of the thermoregulating fluid is arranged to be fed into the thermoregulation chamber 120 through the, or each inlet hole 103a. As shown, for example in figure 19, the aforementioned longitudinal cavity 157 is configured to house at least a tubular element 170a in communication with the thermoregulation chamber 120.

As diagrammatically shown in the alternative embodiment of figure 20, the aforementioned longitudinal cavity 157 can be arranged to house a first and a second tubular elements 170a and 170b. Still with reference to figure 20, the, or each, tubular element 170a and/or 170b, can provide an end portion 171a and/or 171b arranged to engage the main body 100, preferably in a removably way. More in detail, the end portion 171a and/or 171b and the main body 100 can be provided with respective engagement elements 173a, and/or 173b, and 113a, and/or 113b configured to removably engage, for example to provide a plug-in connection. The possibility is also foreseen that the, or each, inlet hole 103a is configured to directly provide a quick connection with the engagement element 173a of the end 171a of the duct 170a, that means without a respective engagement element 113a.

According to an embodiment of the invention, at least a temperature sensor 80 can be provided configured to detect the temperature within the aforementioned thermoregulation chamber 120. In a possible embodiment, at least a temperature sensor 80 can be positioned at a peripheral zone of the thermoregulation chamber 120, for example close to the tubular extrusion duct 101 arranged near the lateral wall of the main body 100, because closer to the lateral wall of the die 1 less is the temperature owing to the heat exchange between the lateral wall of the die 1 and the external environment.

In particular, the, or each, temperature sensor 80 is configured to detect the aforementioned temperature and generate at least a corresponding temperature datum. In a possible embodiment diagrammatically shown in figures 20 and 21, the, or each, temperature sensor 80 can be arranged to send the, or each, temperature datum generated by a control unit 300. This can be, advantageously, configured to increase, or decrease, the flow of the thermoregulating fluid fed to the thermoregulation chamber 120 depending on that the aforementioned, or each, temperature datum is greater, or less, than a predetermined value of temperature (T*) . In particular, the control unit 300, as described above with reference to the figures 17A and 17B, can be configured to adjust the thermal power Pt supplied to the flow of thermoregulating fluid acting on a unit for adjusting the flow 350. This can provide one of the embodiments described above with reference to the figures 17A and 17B.

The, or each, temperature sensor 80 can be operatively connected to the control unit 300 through a connection cable 85. In this case, the connection cable 85 is preferably housed within the longitudinal cavity 157 of the support shaft 155. In the embodiment diagrammatically shown in figure 20, the connection cable 85 is housed within a respective additional tubular element 170b positioned within the aforementioned longitudinal cavity 157.

According to a particular aspect of the invention, furthermore, the aforementioned plurality of the housing holes 102 can comprise a plurality of extrusion groups. More precisely, the housing holes 102 of each extrusion group are arranged at the same distance from a lateral edge of the main body 100 of the die 1. According to an embodiment of the invention, at least a housing hole 102 of an extrusion group is in communication with at least a housing hole 102 of another extrusion group. Therefore, the external wall of at least a tubular extrusion duct 101 housed within a housing hole 102 of an extrusion group is in communication with the external wall of the, or each, tubular extrusion duct 101 which is housed within the other housing hole 102 in communication with the same.

In the embodiments described above with reference to the figures from 18 to 21 an actuation unit, not shown, is provided configured to cause the aforementioned movement, for example the aforementioned rotation of the support shaft 150 about the rotation axis 160. In particular, the actuation unit can comprise gears, or a motor, for example a brushless electric motor, which is operatively connected to the support shaft 150 to cause the aforementioned movement. According to the embodiment diagrammatically shown in figure 22, the actuation unit provides a hollow actuation device 250. More in detail, the actuation device 250 provides a cavity 255 arranged to house, in use, the, or each, tubular duct 170a, 170b. For example, the actuation device 250 can be a hollow electric motor, advantageously a brushless hollow electric motor.

In a further alternative embodiment of the invention, a detection device can be provided for detecting the torque of the motor. More in particular, a command unit can be, furthermore, provided, not shown in the figures for simplicity, configured to command the actuation device 250 depending on the torque of the electric motor that has been detected by the aforementioned detection device.

The different embodiments of the die 1 diagrammatically shown from figure 1 to figure 22, allows to obtain an extrusion speed that is constant over time by thermoregulating the tubular extrusion ducts 101, maintaining constant over time the temperature on the different extrusion lines 116a-116d. Therefore, the present invention allows to solve the technical problem of the prior art dies.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

1. Die (1) for extruding food products comprising a main body (100) having an inlet surface (1A) for the inlet of a starting food product, and an outlet surface (IB) for the exit of an extruded food product (109), said main body (100) being provided of an extrusion group (110) comprising a predetermined number of tubular extrusion ducts (101), each of which having an internal surface (101a) and an external surface (101b), said extrusion group (110) comprising at least a first plurality (115a) of tubular extrusion ducts (101) arranged along a first line (116a) and at least a second plurality (115b) of tubular extrusion ducts (101) arranged along a second line (116b) parallel to the first line (116a), said die being characterized in that said main body (100) and said extrusion group (110) are configured to define at least a thermoregulation chamber (120) in that said main body (100) provides at least an inlet hole (103a) in communication with said, or each, thermoregulation chamber (120) , such that through said, or each, inlet hole (103a) a flow of a thermoregulating fluid can be introduced in said, or each, thermoregulation chamber (120), to adjust the temperature of said plurality of tubular extrusion ducts (101) and in that said main body

(100) and said extrusion group (110) are configured in such a way that the external surface (101b) of at least a tubular extrusion duct (101) of said first plurality (115a) is in hydraulic communication with the external surface (101b) of at least a tubular extrusion duct

(101) of said second plurality (115b) .

2. Die (1) for extruding food products, according to claim 1, wherein said extrusion group (110), furthermore, comprises at least a third plurality (115c) of tubular extrusion ducts (101) arranged on a third line (116c) parallel to said first and second lines (116a, 116b) .

3. Die (1) for extruding food products, according to claim 2, wherein said external surface (101b) of said tubular extrusion duct (101) of said third plurality (116c) is in hydraulic communication with said external surface (101b) of said, or each, tubular extrusion duct of said second plurality (116b) and/or in hydraulic communication with the external surface (101b) of at least a duct of said first plurality (116a) .

4. Die (1) for extruding food products, according to any one of the previous claims, wherein the external surfaces (101b) of said tubular extrusion ducts (101) positioned on the same line ( 116a, 116b, 116c) are in hydraulic communication with each other.

5. Die (1) for extruding food products, according to any one of the previous claims, wherein each of said first line and at least said second line ( 116a, 116b, 116c) is a circumference.

6. Die (1) for extruding food products, according to any one of the previous claims, wherein said external surface (101b) of at least a tubular extrusion duct (101) of said first plurality (115a) is in hydraulic communication with the external surface (101b) of at least a tubular extrusion duct (101) of said second plurality (115b) through said, or each, thermoregulation chamber (120) .

7 . Die (1) for extruding food products, according to any one of the previous claims, wherein said main body

(100) provides a plurality of housing holes (102), each of which configured to house, in use, at least a portion of a respective said tubular extrusion duct

(101) .

8. Die (1) for extruding food products, according to claim 7, wherein each housing hole (102) has a cross- section (SI) greater than the cross-section ( S2 ) of the respective tubular extrusion duct (101) that is housed within the same, in such a way to define a respective thermoregulation chamber (120) .

9 . Die (1) for extruding food products, according to claim 7, or 8, wherein said, or each, housing hole

(102) provides a first portion (102a) arranged to house said tubular extrusion duct (101), and a second portion (102b) having a cross-section smaller than said the cross-section of the first portion (102a), in such a way to define a stop abutment surface (105) for said tubular extrusion duct (101) when is introduced by sliding into the respective housing hole (102) .

10 . Die (1) for extruding food products, according to claim 9, wherein said, or each, housing hole (102) has, furthermore, a third portion (102c) arranged to house an extruding insert (107), said third portion (102c) having a cross-section smaller than said second portion (102b) in such a way to define a second stop abutment surface (106) for said extruding insert (107) .

11. Die (1) for extruding food products, according to any one of the previous claims, wherein said main body (100), furthermore, provides at least an outlet hole (103b) in pneumatic communication with said, or each, thermoregulation chamber (120), said flow of said thermoregulating fluid being arranged to be introduced into said main body (100) through said, or each, inlet hole (103a), and to exit said main body through said, or each, outlet hole (103b), after having passed through said, or each, thermoregulation chamber (120) .

12. Die (1) for extruding food products, according to any one of the previous claims, wherein said, or each, inlet hole (103a) is made at a closing member, or lid, (200), said closing member, or lid, (200) and said main body (100) being configured to mutually engage with each other.

13. Die (1) for extruding food products, according to any one of the previous claims, wherein said, or each, inlet hole (103a) and/or said, or each, outlet hole (103b) is made at a respective position of said inlet surface ( 1A) .

14. Die (1) for extruding food products, according to any one of the previous claims, wherein said, or each, inlet hole (103a) and/or said, or each, outlet hole (103b) is made at a respective position of said outlet surface ( IB) .

15. Die (1) for extruding food products, according to any one of the previous claims, wherein said main body

(100), furthermore, provides a lateral surface (1C), and wherein said, or each, inlet hole (103a) and/or said, or each, outlet hole (103b) is made at a respective position of said lateral surface (1C) .

16. Die (1) for extruding food products, according to any one of the previous claims, wherein said thermoregulating fluid is a heating fluid having a temperature Ta higher than the temperature of said tubular extrusion ducts (101) .

17. Die (1) for extruding food products, according to claim 16, wherein said temperature Ta is set between 50 °C and 200°C.

18. Die (1) for extruding food products, according to any claim from 1 to 17, wherein said thermoregulating fluid is a cooling fluid having a temperature Tb less than the temperature of said tubular extrusion ducts (101) .

19. Die (1) for extruding food products, according to claim 18, wherein said temperature Tb is set between 0 °C and 40 °C.

20. Die (1) for extruding food products, according to any one of the previous claims wherein said main body (100) comprises a first portion (100a) and at least a second portion (100b) respectively provided with a first and a second plurality of housing holes (102', 102"), each tubular extrusion duct (101) of said plurality having a first portion (101') housed within a housing hole (102') of said first plurality of housing holes and a second portion (101") housed within a housing hole (102") of said second plurality of housing holes.

21. Die (1) for extruding food products, according to claim 20, wherein said first and said at least a second portion (100a, 100b) of said main body (100) are configured to move from an assembled configuration to a disassembled configuration.

22. Die (1) for extruding food products, according to any one of the previous claims wherein said main body (100) and said group of tubular extrusion ducts (101) are configured to define a plurality of thermoregulation chambers (120) .

23. Die (1) for extruding food products, according to claim 22, wherein at least a part of said plurality of thermoregulation chambers (120) is in communication with each other.

24. Die (1) for extruding food products, according to any claim from 7 to 23, wherein said, or each, inlet hole (103a) is in communication with at least a part of said housing holes (102) through at least a passageway (104) made in said main body (100) .

25. Die (1) for extruding food products, according to any one of the previous claims wherein the angular distance between two following tubular extrusion ducts (101) of a same line (116a-116d) is substantially constant.

26. Die (1) for extruding food products, according to any one of the previous claims, the distance between two following tubular extrusion ducts (101) of a same line (116a-116d) is set between 5 mm and 20 mm.

27. Apparatus (50) for extruding food products comprising:

- a die according to any claim from 1 to 26;

- a cutting device (150) configured to cut said extruded food product (109) exiting said outlet surface (IB), said cutting device (150) comprising a support shaft (155) and a cutting element (156) arranged to move with respect to said support shaft (155) ;

said apparatus (50) being characterized in that said support shaft (155) provides a longitudinal cavity (157) through which said flow of said thermoregulating fluid is arranged to be fed into said thermoregulation chamber (120) through said, or each inlet hole (103a) .

28. Apparatus (50) according to claim 27, wherein said longitudinal cavity (157) of said hollow support shaft (155) is configured to house at least a tubular element (170a, 170b) in communication with said thermoregulation chamber (120) .

29. Apparatus (50) according to claim 28, wherein at least one of said, or each, tubular element (170a, 170b) has an end portion (171a, 171b) arranged to engage said main body (100), and wherein at least one of said, or each, end portion (171a, 171b) and said main body (100) provide respective engagement elements (173a, 173b; 113a, 113b) configured to removably engage with each other .

30. Apparatus (50) according to any claim from 25 to 29, wherein at least a temperature sensor (80) is, furthermore, provided configured to detect the temperature within said thermoregulation chamber (120) .

31. Apparatus (50) according to claim 30 wherein said, or each, temperature sensor (80) is configured to detect said temperature and to generate at least a corresponding temperature datum, said, or each, temperature sensor (80) being arranged to send said, or each, generated temperature datum to a control unit (300) configured to increase, or decrease, said flow of said thermoregulating fluid fed into said thermoregulation chamber (120) depending on that said, or each, temperature datum is higher, or less, than a predetermined value of temperature (T*) .

32. Apparatus (50) according to claim 31 wherein said control unit (300) is, furthermore, configured to control the thermal power (Pt) arranged to be transmitted to said flow of thermoregulating fluid at a heat exchanger (355) .

33. Apparatus (50) according to any claim from 30 a 32, wherein said, or each, temperature sensor (80) is operatively connected to said control unit (300) by a connection cable (85) arranged to be housed within said longitudinal cavity (157) of said support shaft (155).

34. Apparatus (50) according to claim 33, wherein said support shaft (155) is arranged to house an additional tubular element (170b) configured to house said, or each, connection cable (85) of said, or each, temperature sensor (80) .

35. Method for extruding food products comprising the steps of:

- arranging a die (1) for extruding food products having a main body (100) having an inlet surface (1A) for the inlet of a starting food product, and an outlet surface (IB) for the exit of an extruded food product (109), said main body (100) being provided of an extrusion group (110) comprising a predetermined number of tubular extrusion ducts (101) each of which having an internal surface (101a) and an external surface (101b), said extrusion group (110) comprising at least a first plurality (115a) of tubular extrusion ducts (101a) arranged along a first line (116a) and at least a second plurality (115b) of tubular extrusion ducts (101b) arranged along a second line (116b) parallel to the first line (116a), wherein said main body (100) is provided with at least an inlet hole (103a), and wherein said main body (100) and said extrusion group (110) are configured in such a way to define at least a thermoregulation chamber (120) in communication with said, or each, inlet hole (103a);

- introducing a starting food product into said die (1) through said inlet surface (1A);

- extruding said starting food product through said die (1) thus obtaining an extruded food product exiting said outlet surface (IB);

- generating a flow of a thermoregulating fluid;

- introducing said flow of said thermoregulating fluid into said, or each, thermoregulation chamber (120) through said, or each, inlet hole (103a), said thermoregulating fluid coming into contact with at least an external surface (101b) of a tubular extrusion duct (101) of said first plurality and with the external surface (101b) of at least a duct of said second plurality in hydraulic communication with the same, in such a way to adjust the temperature of said plurality of tubular extrusion ducts (101) .