Nozzle for extruding a protein- and water-rich material and system for the continuous production of an extruded food product with such a nozzle

Description

[0001] The present invention relates to a die for extruding a protein- and water-rich material. It also relates to a continuous preparation system for an extruded food product, comprising such an extrusion die.

[0002] EP 3 524 059 A1, FR 3 125 683 A1 and FR 3 130 517 A1 illustrate the technological background.

[0003] The invention relates to extrusion equipment that forces a material, drawn into an extruder barrel by one or more screws, particularly two screws, rotating on their own axis, to flow through an extrusion die located at the downstream end of the extruder barrel. The screws and the extruder barrel typically belong to an extruder that allows for thermomechanical treatment of the material, in the sense that the material undergoes both a primarily mechanical transformation, through pressure and shearing by the screws, and a primarily thermal transformation, through temperature regulation along the extruder barrel. The extrusion die shapes, textures, and / or fibers the extruded material.

[0004] The invention relates more specifically to the extrusion of protein- and water-rich materials, as well as associated systems that enable the continuous preparation of an extruded food product from a protein- and water-rich raw material. The proteins in the raw material may be of animal, vegetable, and / or other origin. In all cases, the proteins are mixed with a significant proportion of water, and optionally with fats and additives. The resulting mixture is then subjected to the thermomechanical treatment applied by the extruder to be heated and gelled before being shaped in the die. The texturizing, also known as fiberization, of the food product occurs primarily in the die, through which the material exiting the extruder barrel is pushed by the extruder screws.This process of preparing food products based on fibrous proteins is known as "CEMH," which is an acronym for Cooking-Extrusion in a Wet Medium, as well as "HME," which is an acronym for the English expression "High Moisture Extrusion."

[0005] WO 03 / 007729 discloses a CEMH process and associated extrusion equipment, in which a die is provided for the controlled cooling of the material passing through it, by directing the material into a channel that is both long, typically several meters, and rectangular in cross-section. A temperature profile is applied along this channel so as to gradually decrease the temperature of the material between the channel's inlet and outlet. The material in contact with the cooled wall of the channel tends to adhere to this wall, thereby shearing the laminar flow of material in the channel. This shearing helps to develop streamlines within the material paste and tends to align denatured macromolecules in the direction of flow.In practice, the shear rate and flow regime result from the fixed geometry of the channel, so that controlling the fiber formation requires the channel and, therefore, the die processing time to be long.

[0006] Based on the same principle, WO 2019 / 158605 discloses a tubular extrusion die in which the material flows as an annular stream. This stream, following its peripheral direction, is interrupted at its lower end by a die support piece. This die is located at the downstream end of an extruder, at the outlet of which a cylindrical material stream is annularized by the die to form the aforementioned annular stream. For this purpose, the die has, at its inlet, a cone-shaped divergent section whose tip is centered and rotated towards the extruder outlet. The shear applied to the annular material stream in the die is similar to that described in WO 03 / 007729. The corresponding annular channel of the die is therefore also long.

[0007] WO 2022 / 018084 and WO 2023 / 006713 propose an alternative approach, designating a die with a core mounted for rotation within a coaxial tubular casing. Between this rotating core and the fixed casing, an annular channel is defined through which the material flows to pass through the die. These dies allow for highly efficient fiberization because the material flowing through the annular channel of the die is subjected to two combined movements: it is pushed along the axis of the die by the screws of an extruder at the die's outlet, and the material is sheared at its periphery by the rotation of the core. The fiberization rate of the material is adjustable, notably by adjusting the speed at which the rotating core is driven.

[0008] The dies proposed in WO 2022 / 018084 and WO 2023 / 006713 are therefore particularly interesting, but they impose mechanical constraints on some of their components. Indeed, at the die inlet, the cylindrical flow of material pushed by the extruder is enclosed by a cone integrated into the upstream end of the rotating core. The axial hydrostatic thrust forces applied to this cone by the material exiting the extruder are therefore substantial and are transmitted directly to the rest of the rotating core, which must therefore be axially constrained accordingly, typically by ball bearings. These axial forces are absorbed by a support structure for the die, which risks local deformation unless it is dimensioned accordingly, or even fixed to the ground, with the drawback of making this support structure difficult to move and therefore impractical.Furthermore, although the downstream part of the rotating core, located outside the fixed envelope, is supported and guided in rotation, the rotating core tends, due to its own weight and length, to bend at its upstream part, in other words at the level of the aforementioned cone and the annular channel between the envelope and this upstream part of the rotating core, which can induce a lack of coaxiality between the latter and, therefore, a degradation of the adjustment of the fibration of the material passing through the die.

[0009] The aim of the present invention is to propose a rotary core extrusion die that is more practical and more efficient.

[0010] To this end, the invention relates to a die for extruding a material rich in protein and water, comprising: an envelope, which is tubular, centered on an axis, and which is provided with a central inlet through which the material enters the envelope to be pushed through the die, and a core, which is coaxial with the envelope and mounted to rotate around the axis relative to the envelope, in which the core includes an upstream portion, extending at least partially inside the casing such that, between an inner surface of the casing and an outer surface of the core, a channel is defined having an annular cross-section centered on the axis, which channel includes an upstream end and a downstream end, which are opposite each other along the axis and between which the material pushed through the die flows in the channel, progressing from the upstream end to the downstream end of the channel, and in which the core also includes a downstream portion, extending outside the casing and coupled to a drive for the die, adapted to rotate the core around the axis, characterized in that the die further comprises a male divergent part which is: fixedly attached to the casing and received coaxially inside the casing so that, between the male divergent part and the casing,A passage is delimited, through which the central inlet of the casing and the upstream end of the channel are connected, and which is shaped so that the material pushed through the die progresses in the passage, from the central inlet of the casing towards the upstream end of the channel, forming a flow of material that diverges from the axis downstream and is distributed around the axis, and abuts axially to the upstream part of the core, supporting and guiding the core in rotation.

[0011] Thanks to the invention, a cylindrical material flow entering the die is annularized by the male divergent end by applying hydrostatic thrust forces to the latter. These forces are not absorbed by the rotating core, but by the die's outer casing. The dimensioning of the fixed connection between the male divergent end and the casing is straightforward, requiring only a simple static mechanics calculation, and all mechanical stresses resulting from the hydrostatic thrust remain localized within a well-defined region of the die. Any deformations induced by these mechanical stresses also remain localized, notably without significant impact on the die's support structure. This support structure can thus be easily adapted for mobility on the ground, for example, by means of casters.In particular, no hydrostatic thrust is transmitted to the support structure via the rotating core, thus avoiding the need to stiffen the portion of the support structure that axially restrains the rotating core, typically at its downstream end. Simultaneously, the male divergent element incorporates a support and rotational guidance function for the rotating core, cooperating for this purpose with the upstream portion of the rotating core, independently of the material flow through the die. This results in excellent control of the coaxiality between the rotating core and the casing, and consequently, excellent control of the material's fiber formation as it passes through the die according to the invention. The performance and practicality of the die according to the invention are therefore remarkable.

[0012] Depending on additional advantageous characteristics of the die according to the invention, taken individually or in all technically possible combinations: The male divergent part defines an internal housing, which is separated from the passage and into which the upstream portion of the core is received, supported, and guided in rotation. The die also includes a bearing, centered on the axis and radially interposed between the upstream portion of the core and a wall of the male divergent part, thus defining the internal housing. The passage is defined by an external surface of the male divergent part, which is conical, centered on the axis, and diverges downstream. The casing includes a die sleeve, which defines the inner surface of the casing, and within which the casing also includes a female divergent part (i) which is fixedly attached to the die sleeve, (ii) which has the central inlet of the casing, and (iii) within which the male divergent part is arranged coaxially to define the passage between the female and male divergent parts.The male divergent end is fixedly attached to the casing by respective portions of the male divergent end and the casing, one or both of which are perforated to allow passage for the material flow. The male divergent end includes a peripheral flange (i) by which the male divergent end is fixedly attached to the casing, (ii) which extends transversely to the axis across the material flow, and (iii) which is traversed by passages in the peripheral flange, distributed around the axis, through which the material flow passes. The peripheral flange is axially clamped between the die sleeve and the female divergent end of the casing. The die also includes a sealing element designed to seal a rotating mechanical decoupling interface between the male divergent end and the core.The sealing element is (i) received in a peripheral groove of the upstream part of the core, and (ii) applied radially against a ring of the male divergent, this ring having an outer surface that is flush with said outer surface of the upstream part of the core.

[0013] The invention also relates to a system for the continuous preparation of an extruded food product, comprising: a raw material which is rich in protein and water, an extruder comprising at least one screw and an extruder sleeve inside which said at least one screw is driveable in rotation so as to apply a thermomechanical treatment to the raw material, and a die, which is as defined above and whose casing is fixedly attached to the extruder sleeve so that, at the exit of the extruder sleeve, the material is pushed by said at least one screw through the die via the central inlet of the casing.

[0014] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the drawings in which: [ Fig. 1 ] there figure 1 is a perspective and partially schematic view of a system according to the invention; [ Fig. 2 ] there figure 2 is a cross-section, partially schematic, of part of the system of the figure 1 according to plan II of the figure 1 ; Fig. 3 ] there figure 3 is a larger-scale view of a framed area III on the figure 2 ; Fig. 4 ] ] Fig. 5 ] THE figures 4 And 5 are perspective views, from different respective angles of observation, of a male divergent belonging to the system of the figure 1 ; And [ Fig. 6 ] there figure 6 is a larger-scale view of an area framed VI on the figure 3 .

[0015] On the figures 1 And 2A system for the continuous preparation, by extrusion, of a food product 1 intended for human and / or animal consumption is schematically represented. This system mainly comprises a raw material 3 and an extrusion machine 10, which will be described in more detail below.

[0016] Raw material 3 is rich in protein and water. More precisely, raw material 3, that is to say the set of ingredients which are processed by the extrusion machine 10 to form the food product 1, contains mainly, in other words more than 50% by weight, water and protein, as well as, to a lesser extent or even marginally, dietary fiber and / or starch, and possibly fats and additives.

[0017] The food product 1, as obtained from the extrusion machine 10, is textured, in other words, fibrous. The food product 1 comprises between 25 and 90% by weight, preferably between 50 and 85% by weight, of water and also comprises, by weight on a total dry matter basis, between 20 and 90% protein.

[0018] The proteins in raw material 3, and therefore in food product 1, are of plant origin and / or animal origin and / or at least one other origin. Plant-based proteins come, for example, from legumes, cereals, and / or protein crops (soybeans, wheat, peas, corn, chickpeas, lentils, etc.). Animal-based proteins come, for example, from fish, meat, milk, and / or eggs. The other protein sources include, for example, fungi, algae, insects, cultured meat, etc.

[0019] Food product 1 also comprises, by weight in the total dry matter, between 0 and 50% dietary fiber and between 0 and 50% starch, the sum of dietary fiber and / or starch preferably being greater than 0.01%. Dietary fiber is, for example, fiber of plant origin and starch is, for example, of plant origin, in its native, pregelatinized or modified state.

[0020] Food product 1 may also include, by weight on the total dry matter, between 0 and 20% fat, in particular of vegetable and / or animal origin, and / or functional ingredients, such as lecithins, caseinates or other ingredients.

[0021] As clearly visible on the figures 1 And 2 The extrusion machine 10 mainly comprises an extruder 100 and a die 200 which will be detailed later.

[0022] As schematically represented on the figure 1 The extruder 100 comprises an elongated barrel 110, extending along a geometric axis XX and centered on this axis. Inside the barrel 110, two screws 120 extend parallel to the axis XX, being received in a central longitudinal bore of the barrel, centered on the axis XX. In practice, in a manner known per se, each screw 120 includes, for example, a central screw shaft on which a set of screw elements is mounted. In all cases, the two screws 120 extend on either side of the axis XX, while being interpenetrating, the bore of the barrel 110 thus having a bilobed transverse profile.

[0023] The screws 120 are designed to be driven in rotation about their central axis by a drive unit, not shown in the figures, engaged with the upstream end of the screws 120, namely the one on the right on the figure 1 emerging outside of sheath 110.

[0024] The screws 120 are designed, by virtue of their threaded profile, to drive the raw material 3 inside the barrel 110 along the axis XX, from an upstream part of the barrel 110, into which the ingredients of the raw material 3 are introduced inside the central longitudinal bore of the barrel 110, to the downstream end of the barrel 110, the terms "upstream" and "downstream" being oriented in the direction of progression of the material in the extrusion machine 10 under the action of the screws 120, this direction of progression being from right to left on the figures 1 à 3 And 6 .

[0025] In practice, the sheath 110 here comprises several modular elements 111 which, as schematically shown on the figure 1 , follow one another along the axis XX. Each of the modular elements 111 internally delimits a corresponding part of the central longitudinal bore of the sleeve 110, these bore parts being in line with each other along the axis XX in the assembled state of the modular elements 111, as on the figure 1 On the figure 1 , the modular element which is furthest downstream among the modular elements 111 is only partially represented, which allows observation of the corresponding bore part, it being noted that, for reasons of visibility, the screws 120 are also not represented in this bore part.

[0026] In the embodiment shown in the figures, the upstream modular element of the sleeve 110, the furthest of the modular elements 111, allows the ingredients of the raw material 3 to be introduced into its bore. For this purpose, in a manner known per se and not detailed here, this furthest modular element is provided with an orifice 112 which, transverse to the axis XX, opens the bore of this furthest modular element to the outside, here upwards. More generally, it is understood that, among the various modular elements 111 of the sleeve 110, one or more of them allow the solid and / or liquid ingredients of the raw material 3 to be introduced into the central longitudinal bore of the sleeve 110 for processing by the extrusion machine 10.

[0027] As mentioned in the introductory section of this document, the screws 120 are designed not only to drive the material to be extruded, but also to shear and pressurize the raw material 3, thereby transforming it primarily through mechanical processes. This aspect of the extruder 100 is well-known in the field and will not be described further here. Similarly, also as mentioned in the introductory section, the barrel 110 is advantageously designed to regulate the temperature of the material to be extruded along the barrel 110, thus transforming this material primarily through thermal processes. Indeed, all or part of the modular elements 111 of the barrel 110 are thermoregulated and / or allow steam to be injected into the barrel 110 and / or allow the material being extruded to be degassed in the barrel 110. Again, this aspect of the extruder 100 being well known in the field, it will not be described further here.More generally, the sleeve 110 and the screws 120 are designed to apply a thermomechanical treatment to the raw material 3 as this material progresses from the upstream end of the sleeve 110 to the downstream end of the sleeve 110. The material resulting from this thermomechanical treatment and exiting the sleeve 110 is referenced 5 on the. figures 2 And 3 .

[0028] At its downstream end, the sleeve 110 advantageously includes an end element 113, commonly called a "front plate" in the field. The end element 113 is fixedly attached to the rest of the sleeve 110, here at the downstream end of the most downstream modular element, among the modular elements 111, of the sleeve 110. As clearly visible on the figures 2 And 3The end element 113 internally delimits a through bore 114, which is centered on the axis XX and forms a downstream end portion of the central longitudinal bore of the sleeve 110, receiving, where applicable, the downstream end of the screws 120. Here, the bore 114 of the end element 113 extends in the axial continuation of the bore portion of the most downstream modular element among the modular elements 111. This bore 114 is adapted to channel the material 5 pushed downstream by the screws 120, so as to ensure appropriate pressure and filling rate for the central longitudinal bore of the sleeve 110. For this purpose, the bore 114 is, for example, at least partially constricted downstream, here in a plane perpendicular to the plane of the figures 2 And 3 and / or equipped with a transverse grid, not shown in the figures. This aspect of the extruder 100 is not limiting to the invention and will not be described further here.

[0029] Focusing more specifically on the die 200, this die 200 is designed to be passed through by the material 5 for the purpose of extruding the latter. In the assembled state of the extrusion machine 10, the die 200 is arranged at the downstream end of the barrel 110 of the extruder 100 so that the material 5 exiting the barrel 110 is forced, by the action of the screws 120 of the extruder 100, to flow through the die 200.

[0030] As clearly visible on the figures 1 à 3 The die 200 comprises a tubular casing 210, centered on a geometric axis which, in the assembled state of the extrusion machine 10, coincides with axis XX and will therefore be considered axis XX hereafter. The casing 210 thus has two opposite ends along axis XX, namely an upstream end 210A and a downstream end 210B. The casing 210 delimits an internal volume which, due to its tubular shape, is essentially closed around axis XX by the casing 210, while opening axially to the outside of the casing 210 at its upstream ends 210A and downstream ends 210B.

[0031] In the assembled state of the extrusion machine 10, the barrel 110 of the extruder 100 and the casing 210 of Figure 200 are fixedly joined to each other. In practice, the casing 210, in particular its upstream end 210A, is fixedly joined for this purpose, directly or indirectly, to a downstream part of the barrel 110, in particular, as here, to the terminal element 113 of this barrel.

[0032] At its upstream end 210A, the enclosure 210 is provided with a central inlet 211, which is centered on the axis XX and through which the axis XX passes. This central inlet 211 connects the internal volume of the casing 210 with the outside of the casing 210. In the assembled state of the extrusion machine 10, the material 5 pushed by the screws 120 of the extruder 100 enters the internal volume of the casing 210 through the central inlet 211 to be pushed through the die 200: in the embodiment considered here, the central inlet 211 is butted to the bore 114 of the terminal element 113 of the sleeve 110, more precisely to the downstream end of this bore 114, in order to allow the flow of the material 5 between the bore 114 and the central inlet 211.In practice, the cross-section of the central inlet 211, that is, its cross-section in a plane perpendicular to the axis XX, is advantageously matched to that of the downstream end of the central longitudinal bore of the sleeve 110, here to that of the downstream end of the bore 114, particularly to limit pressure losses and disturbances in the flow of material. Preferably, the cross-section of the central inlet 211 has a circular contour, centered on the axis XX.

[0033] In the embodiment shown in the figures, the casing 210 comprises a female divergent 212 and a sleeve 213, which follow one another along the axis XX, the sleeve 213 being positioned downstream of the female divergent 212, as clearly visible in the figures 1 à 3 The female divergent 212 and the sheath 213 each have a tubular shape, in the sense that they delimit respective internal volumes corresponding respectively to sub-volumes of the internal volume of the envelope 210. The female divergent 212 and the sheath 213 are fixedly joined to each other, here by a fixing collar 214.

[0034] The female divergent 212 presents the upstream end 210A of the casing 210, being provided with the central inlet 211. Here, in the assembled state of the extrusion machine 10, the terminal element 113 of the sleeve 110 of the extruder 100 is secured to the casing 210 of the die 200 by means of the female divergent 212, the terminal element 113 being for example bolted onto the female divergent 212.

[0035] In all cases, the female divergent 212 delimits an internal surface 212A, which closes the internal volume of the female divergent 212 all around the axis XX and through which the central inlet 211 is connected along the axis XX to the internal volume of the sleeve 213: as clearly visible on the figures 2 And 3 This internal surface 212A of the female divergent 212 is centered on the axis XX while widening downstream. According to a practical embodiment shown in the figures, this internal surface 212A is frustoconical, being centered on the axis XX and diverging downstream. Here, this internal surface 212A is entirely smooth.

[0036] The sleeve 213 of the casing 210 defines an internal surface 213A, which closes the internal volume of the sleeve 213 all around the axis XX and through which the internal volume of the female divergent 212 is connected along the axis XX to the exterior of the casing 210: in the embodiment shown in the figures, this internal surface 213A of the sleeve 213 is cylindrical with a circular base, centered on the axis XX. Here, the internal surface 213A extends over the entire axial extent of the sleeve 213 and opens onto the downstream end 210B of the casing 210, this downstream end 210B being thus presented by the sleeve 213.

[0037] In the form of implementation considered here, and as clearly visible on the figures 1 And 2The sleeve 213 comprises modular elements 215 arranged along the axis XX. In the illustrated example, there are three of these modular elements 215. Each modular element 215 internally delimits a corresponding portion of the internal volume of the sleeve 213 and thus delimits a corresponding portion of the internal surface 213A. In practice, these modular elements 215 are assembled in pairs, for example, by fastening collars 216.

[0038] Furthermore, it should be noted that the specific features of the outer face of the 210 envelope are not limiting.

[0039] In addition to envelope 210, stream 200 includes a core 220. As clearly visible on the figures 1 And 2, the core 220 has an elongated shape, centered on a geometric axis which, in the assembled state of the extrusion machine 10, coincides with the XX axis and which will therefore be considered as the XX axis thereafter. Within the 200 channel, the core 220 is coaxial with the envelope 210, being partially arranged inside the latter, in other words within the internal volume of the envelope 210. The core 220 thus includes two parts following the axis XX, namely an upstream part 220.1, which extends at least partially inside the envelope 210, in other words within its internal volume, and a downstream part 220.2, which extends entirely outside the envelope 210. In the embodiment considered in the figures, the upstream part 220.1 of the core 220 extends essentially inside the envelope 210, while emerging, downstream, from the downstream end 210B of the envelope 210.

[0040] In all cases, the upstream part 220.1 of the core 220 is provided with an external surface 220A, that is to say a surface turned radially in the opposite direction to the axis XX, which extends over the entire axial extent of the upstream part 220.1 of the core 220 and which is arranged both opposite, radially to the axis XX, and coaxially with the internal surface 213A of the sleeve 213 of the envelope 210: here, this external surface 220A of the core 220 is cylindrical with a circular base, centered on the axis XX.

[0041] In all cases, the inner surface 213A of the envelope 210 and the outer surface 220A of the core 220 radially delimit between them a channel 230 having a cross-section, that is to say a section in cross-section perpendicular to the axis XX, which is annular and centered on the axis XX. This channel 230 extends along the axis XX from an upstream end 230A to a downstream end 230B, with the upstream end 230A facing axially towards the extruder 100 in the assembled state of the extrusion machine 10. The inner surface 213A of the casing 210 defines the channel 230, forming its outer periphery, from the upstream end 230A to the downstream end 230B. The outer surface 220A of the core 220 defines the channel 230, forming its inner periphery, from the upstream end 230A to the downstream end 230B. The channel 230 extends continuously around the axis XX, that is, over 360°.In operation, the material 5 exiting the casing 110 flows into the channel 230 to pass through the die 200, progressing in the channel 230 from the upstream end 230A to the downstream end 230B of the channel 230. The material flow in the channel 230, which is referenced 7 on the . figures 2 And 3 , thus presents an annular shape, centered on the XX axis.

[0042] In the embodiment shown in the figures, the inner surface 213A of the casing 210 and the outer surface 220A of the core 220 are each cylindrical with a circular base. It is understood that the annular cross-section of the channel 230 is constant from its upstream end 230A to its downstream end 230B.

[0043] In practice, as shown on the figure 1 The die 200 comprises a support structure 240, on which the casing 210 rests fixedly and which is supported by the ground. This support structure 240 is advantageously equipped with casters 241 by which the support structure 240 rests on the ground. These casters 241 allow the die 200 to be moved relative to the ground when it is not in use, for example, for cleaning, maintenance, or successive use with several extruders. Of course, the shape of the support structure 240 is not limited.

[0044] Regardless of its embodiment, the core 220, unlike the casing 210, is not fixed relative to the support structure 240 and the barrel 110 of the extruder 100 in the assembled state of the extrusion machine 10, but is designed to rotate about the axis XX. Thus, within the die 200, the core 220 is mounted to rotate about the axis XX relative to the casing 210. The outer surface 220A of the core 220 is therefore also rotated about the axis XX.

[0045] For the purpose of driving the core 220 in rotation around the axis XX, the die 200 includes a motor 250 which is coupled to the downstream portion 220.2 of the core 220. In practice, the technical specifications of the motor 250 are not limiting. For example, this motor 250 is electric and its drive output is, outside the casing 210, directly or indirectly connected to the downstream portion 220.2 of the core 220. According to a practical arrangement, which is not shown in the figures, the motor 250 advantageously rests on the supporting structure 240, the fixed components of this motor being permanently attached to this supporting structure 240.

[0046] As an example of a possible realization of the core 220, which is implemented in the figures, the core 220 comprises a central shaft 221 and a gearing element 222, fixedly joined to each other. The central shaft 221 is centered on the axis XX, and an upstream portion of this central shaft 221, which belongs to the upstream portion 220.1 of the core 220, is arranged inside the casing 210, while a downstream portion of the central shaft 221, belonging to the downstream portion 220.2 of the core 220, is located outside the casing 210 where this downstream portion of the central shaft is coupled with the motor 250. The stepping element 222 belongs to the upstream portion 220.1 of the core 220 and is arranged essentially inside the casing 210, being fixedly attached to the upstream portion of the central shaft 221. The stepping element 222 delimits the external surface 220A.

[0047] As clearly visible on the figures 2 And 3, the 200 series also includes a male divergent 260 which is represented alone on the figures 4 And 5 Within the 200 channel, this male divergent 260 is arranged coaxially inside the envelope 210, more precisely essentially in the internal volume of this envelope 210, and is located both immediately upstream of the core 220 and downstream of the central inlet 211.

[0048] As clearly visible on the figures 4 And 5 The male divergent 260 is shaped like a Chinese hat, centered on the XX axis. Thus, as clearly visible on the figure 4 On its upstream side, that is, its axial side facing the central inlet 211, the male divergent 260 gradually flares downstream from a pointed upstream end of the male divergent 260, centered on the axis XX: in the embodiment considered here, the male divergent 260 delimits, on its upstream side, an external surface 260A which is conical, being centered on the axis XX and diverging downstream. In the example shown in the figures, this external surface 260A is entirely smooth, as clearly visible in the figure 4 As clearly visible on the figure 5 On its downstream side, that is, its axial side facing away from the central inlet 211, the male divergent 260 is hollow and defines an internal housing 261, which is centered on the axis XX and opens axially onto the downstream side of the male divergent 260. The internal housing 261 does not open onto the external surface 260A, which is completely separated from the internal housing 261 by a solid wall 262 of the male divergent 260, which is generally conical and which defines the internal housing 261. In the embodiment considered here, the internal housing 261 is advantageously stepped with respect to the axis XX.

[0049] Following an advantageous feature whose significance will become apparent later, the male divergent 260 is provided with a peripheral flange 263, which is centered on the axis XX and runs all around this axis XX. As clearly visible on the figures 4 And 5The peripheral flange 263 extends from the solid wall 262, projecting radially from the outer surface 260A. Here, the peripheral flange 263 is axially located at the downstream end of the male divergent 260, that is, at the axial level where the solid wall 262 has its largest outer diameter. In all cases, as clearly visible on the figures 4 And 5The peripheral flange 263 is provided with openings 264, each of which passes axially through the peripheral flange 263, more precisely through an inner portion 263.1 thereof, that is, a portion facing the axis XX. The openings 264 are distributed around the axis XX, advantageously in a regular manner. Here, each of the openings 264 has an arched profile, centered on the axis XX. Between the two openings 264 of each pair of openings adjacent to each other around the axis XX, the peripheral flange 263 includes a tab 265 which, around the axis XX, separates the two openings of the pair of openings in question from each other and which, radially to the axis XX, connects to the wall 262 an outer portion 263.2 of the peripheral flange 263, externally surrounding the openings 264.

[0050] According to another advantageous feature, the significance of which will become apparent later, the male divergent 260 has, at its downstream end, a ring 266, or cylindrical protrusion, which is centered on the axis XX and extends axially downstream from the solid wall 262, more precisely from the downstream axial edge of this solid wall. As clearly visible on the figures 5 And 6 , the ring 266 is inscribed inside the inner contour of the peripheral flange 263 and is provided with an outer surface 266A which is here both cylindrical with a circular base, centered on the axis XX, and flush with the respective edges of the slots 264, radially turned towards the axis XX.

[0051] As clearly visible on the figures 2 , 3 And 6The male divergent 260 is fixedly attached to the casing 210 within the die 200, being received within the internal volume of the casing 210. Thus, a passage 270 is defined between the male divergent 260 and the casing 210, through which the central inlet 211 of the casing 210 and the upstream end 230A of the channel 230 are connected. In the embodiment considered here, the male divergent 260 is essentially housed inside the female divergent 212 of the casing 210, and the passage 270 is essentially defined between the inner surface 212A of the female divergent 212 and the outer surface 260A of the male divergent 260. The material pushed through the die 200 progresses through this passage. 270, from the central inlet 211 towards the upstream end 230A of the channel 230, forming a flow of matter 6 of generally frustoconical shape, centered on the axis XX and diverging downstream.More generally, the passage 270, delimited between the male divergent 260 and the casing 210, is shaped so that the material flow 6, formed by the material progressing through this passage 270 from the central inlet 211 of the casing 210 to the upstream end 230A of the channel 230, diverges from the axis XX downstream and is distributed around the axis XX. The passage 270 thus makes it possible to cancel the cylindrical flow of material 5 entering the die 200.

[0052] In the embodiment considered here, the fixed connection between the male divergent 260 and the casing 210 is advantageously achieved by the peripheral flange 263 of the male divergent 260. The attachment of the peripheral flange 263 to the casing 210 is preferably achieved by axially pinching the peripheral flange 263, in particular its outer portion 263.2, between the female divergent 212 and the sleeve 213 of the casing 210, advantageously with axial interposition of a sealing gasket 280, as clearly visible in the figure 6 . To this end, one or both of the female divergent 212 and the sheath 213 are provided with a peripheral groove in which the peripheral flange 263 is assembled by mortise and tenon joint, as clearly visible on the figure 6 The fixing between the peripheral flange 263 and the casing 210 is advantageously reinforced by one or more pins 281, which are attached axially through the peripheral flange 263, in particular its outer part 263.2, and which allow to improve both the positioning transverse to the axis XX and the locking against rotation around this axis XX between the peripheral flange 263 and the casing 210.

[0053] It is understood that, in the embodiment shown in the figures, the peripheral flange 263, in particular its inner part 263.1, is located on the passage 270, extending transversely to the axis XX, across the flow of material 6 flowing in the passage 270. That being said, the openings 264 allow the peripheral flange 263 to be traversed by the passage 270, in the sense that the peripheral flange 263 is passable by the flow of material 6 via these openings 264, as indicated by the dashed lines on the figure 6 It is therefore understood that the flow section of the 264 lights is preferably as large as possible.

[0054] More generally, in line with the considerations immediately above, it is understood that the passage 270 is designed to pass through one and / or the other of the parts, which belong respectively to the male divergent 260 and to the envelope 210 and by which the male divergent 260 is fixedly attached to the envelope 210. For this purpose, one and / or the other of the two aforementioned parts belonging respectively to the male divergent 260 and to the envelope 210 are perforated through and through by one or more lights functionally analogous to the lights 264 which, in the example illustrated in the figures, each pass axially through and through the peripheral flange 263: this or these lights allow the flow of material 6 flowing in the passage 270 to pass through the two aforementioned parts belonging respectively to the male divergent 260 and to the envelope 210.

[0055] In all cases, since the male divergent element 260 is fixedly attached to the casing 210, the core 220 rotates around the axis XX relative to the male divergent element 260. As clearly visible on the figures 2 And 3With respect to the core 220, the male divergent part 260 is axially butted to the upstream portion 220.1 of the core 220, supporting and guiding the core 220 in rotation, outside the passage 270. To this end, in the embodiment considered here, the upstream portion 220.1 of the core 220, in particular an upstream end of the central shaft 221, is partially received in the internal housing 261 of the male divergent part 260, being supported and guided in rotation by the solid wall 262 which separates the internal housing 261 from the passage 270. Since the internal housing 261 is stepped, a bearing 290, in particular a plain bearing, is advantageously interposed radially between the upstream portion 220.1 of the core 220, in particular the aforementioned upstream end of the central shaft 221, and the solid wall 262 of the male divergent 260.

[0056] In practice, as clearly visible on the figure 6 , a sliding washer 292 is advantageously interposed axially between the male divergent 260 and the upstream part 220.1 of the core 220: this washer 292 allows the male divergent 260 and the core 220 to be decoupled in rotation from each other. Here, this sliding washer 292 is interposed axially between an upstream end shoulder 222A of the staging member 222 of the core 220, extending radially in retreat from the outer surface 220A of the upstream part 220.1 of the core 220, and the ring 266 of the male divergent 260, while providing that the outer surface 266A of the ring 266 and an outer surface 292A of the sliding washer 292 are flush with the outer surface 220A of the upstream part 220.1 of the core 220: in this way, the rotational decoupling between the male divergent 260 and the core 220 is effective, without inducing pressure losses, nor disturbances in the flow of material in the upstream end 230A of the channel 230.

[0057] Furthermore, to seal the rotary decoupling between the male divergent 260 and the core 220 and thus prevent any substantial leakage of material passing through the die 200, the latter advantageously includes a sealing element 294 which is particularly visible at the figure 6 In practice, the embodiment of this sealing element is not limited; the sealing element 294 may thus comprise a single O-ring, as illustrated in the figures, or several O-rings and / or a four-lobe seal and / or a mechanical seal and / or etc. In all cases, as clearly visible on the figure 6 This sealing element 294 is received in a peripheral groove 223 of the upstream portion 220.1 of the core 220, this peripheral groove 223 being delimited here at an upstream end of the stepping element 222. Furthermore, the sealing element 294 is applied radially against the ring 266 of the male divergent element 260, more precisely against an inner surface 266B of this ring 266. To facilitate cleaning of the peripheral groove 223 and / or maintenance of the sealing element 294, the groove 223 is axially delimited by a dedicated element 296 which is advantageously attached in a removable manner to the upstream portion 220.1 of the core 220: here, as clearly visible on the figure 6 , this dedicated element 296 includes a stop ring 297, retained axially on the staging element 222 of the core 220, and a sliding washer 298, axially interposed between the stop ring 297 and the sealing element 294.

[0058] Of course, the embodiment of the sealing element 294, detailed above, is specific to the example illustrated in the figures. It is understood that, more generally, the die 200 advantageously includes a sealing element, such as the sealing element 294, designed to seal the mechanical rotary decoupling interface between the male divergent end 260 and the core 220.

[0059] We will now describe the operation of extrusion machine 10.

[0060] The ingredients of the raw material 3 are introduced into the sleeve 110 and then conveyed downstream by the screws 120, while being transformed by the thermomechanical treatment applied by the sleeve and the screws. The material 5 exiting the sleeve 110 is pushed, by the screws 120, through the die 200, entering it through the central inlet 211 and flowing through the die 200 successively through the passage 270 and the channel 230.

[0061] In passage 270, the material forming the material flow 6 is distributed all around the axis XX, while moving away from the axis XX downstream, to reach the upstream end 230A of the channel 230. The hydrostatic thrust of the material flow 6 generates axial stresses on the male divergent 260, which are fully transmitted to the envelope 210 and, through it, to the supporting structure 240, without passing through the core 220.

[0062] In channel 230, the material forms the material stream 7 and flows from the upstream end 230A to the downstream end 230B of channel 230, where the material exits the casing 210 to form the food product 1. As it flows through channel 230, the material in the material stream 7 is sheared due to the rotational drive around the axis XX of the core 220 by the drive 250, the material stream 7 thus spiraling around the axis XX downstream. The technical considerations relating to this shearing are explained in detail in WO 2022 / 018084 and WO 2023 / 006713, to which the reader may usefully refer. In all cases, the fibration of the material of the material flow 7, resulting from this shearing, is controlled due, in particular, to the positioning and rotational guidance of the core 220 relative to the envelope 210 thanks to the male divergent 260.

[0063] It should be noted that, at the openings 264 through which the material flow 6 passes the peripheral flange 263 during its flow in the passage 270, the material flow 6 is locally interrupted, around the axis XX, by the tabs 265. In other words, the tabs 265 form point obstacles for the material flow 6, which are located here immediately upstream of the end 230A of the channel 230. It is understood that the material flow 6, which is subdivided by cutting as it passes through the peripheral flange 263 to bypass the tabs 265, tends to rejoin all around the axis XX downstream of the tabs 265. Therefore, the die 200 allows, to a certain extent, for taking advantage of this situation.Indeed, since the material flow 7 can be controlled to spiral around the axis XX downstream by controlling the motor 250, the rejoining of the material flow downstream of the tabs 265 is easily managed within the material flow 7 by adjusting the rotational speed of the core 220. Thus, within the rheological limits of the material actually extruded and depending on the operating parameters of the die 200, particularly the rotational speed of the core 220, and the dimensions of the tabs 265, it is possible to obtain at the outlet of the channel 230 either a completely homogeneous material flow around the axis, i.e., without any perceptible trace of passing through the peripheral flange 263, or a material flow incorporating more or less pronounced cutting lines resulting from the presence of the tabs. 265.

[0064] As a direct continuation of the above, it should be noted that the shape of the legs 265 is not limited to that of the example illustrated in the figures. On the contrary, it is understood that multiple geometries are possible for the legs 265. Such geometries allow, in particular, for the aforementioned cut lines to be more or less pronounced. Such geometries also allow, where applicable, considerations of hygiene, depending on their influence on the ease of cleaning the legs 265 and / or on the accumulation / removal of material at the level of the legs 265. By way of non-limiting examples, rather than, as in the example illustrated in the figures, each of the legs 265 having, on its upstream side, a flat facet inscribed in a geometric plane perpendicular to the axis XX, each of the legs 265 can be shaped to be pointed or convex upstream, gradually flaring out downstream, notably in the manner of a boat's prow.The invention encompasses these various geometries for the legs 265.

[0065] Finally, various modifications and variations to the extrusion machine 10 described so far are also possible. As examples, several corresponding aspects are listed below, which can be considered individually with the above, or in combination with each other: Rather than being entirely smooth as in the example illustrated in the figures, the outer surface 260A of the male divergent 260 and / or the inner surface 212A of the female divergent 212 may have a non-smooth surface finish, particularly to influence the flow of the material stream 6 as it progresses through the passage 270, diverging downstream from the axis XX and spreading out around the axis XX. Thus, the outer surface 260A and / or the inner surface 212A may, in particular, be provided with projecting ribs, each extending lengthwise parallel to the axis XX, or inclined relative to the axis XX, or wrapped around the axis XX. Such ribs can, where appropriate, join the 265 tabs and thus participate in a pre-orientation of the material with respect to the aforementioned cutting lines.As mentioned above, rather than by the peripheral flange 263, the fixed connection between the male divergent 260 and the casing 210 is achieved by various arrangements, such as bolting the male divergent 260 onto the female divergent 212. Unlike what is schematically illustrated in the . figures 1 And 2 The inner surface 220A of the core 220 may slightly emerge, downstream, from the downstream end 210B of the casing 210 and / or extend downstream by an outlet deflector so as to exert a counter-pressure against the flow of material exiting the channel 230. In this regard, the reader may usefully refer to WO 2022 / 018084 and WO 2023 / 006713. The core 220 can be equipped with a material-breaking tool exiting the casing 210. This breaking tool utilizes the rotational drive of the core 220 to act on the food product 1 as it exits the channel 230. The core 220 can include several successive modules along the axis XX, as described in WO 2022 / 018084 and WO 2023 / 006173, to which the reader may refer in this regard. Rather than being cylindrical with a circular base, one or both of the inner surface 213A of the casing 210 and the outer surface 220A of the core 220 can be frustoconical, centered on the axis XX and diverging downstream, as explained in detail in WO 2023 / 006173, to which the reader may refer for further details. Regardless of the form of realization of the envelope 210 and the core 220, one and / or the other of the envelope 210 and the upstream part 220.The core 120 can be thermoregulated, meaning each is designed to control its temperature in such a way as to maintain it, at least locally, at a predetermined and advantageously adjustable value, despite heat exchange with its immediate environment. In this way, the casing 210 and / or the upstream portion 220.1 of the core 220 are able to influence the temperature in the channel 230, more precisely the temperature of the material flow 7, by means of heat exchange with the material through, respectively, the inner surface 213A and the outer surface 220A. Practical details relating to such thermoregulation are given in WO 2022 / 018084 and WO 2023 / 006713, to which the reader may usefully refer. Naturally, the thermoregulation of the casing 210 encompasses the potential thermoregulation of the female divergent 212.As for the male divergent 260, its thermoregulation is optionally conceivable, either from the envelope 210 via dedicated arrangements at the interface between the upstream part 220.1 of the core 220 and the male divergent 260, such as rotating joints.

Claims

1. A die (200) for extruding a material high in proteins and in water, comprising: - a casing (210), which is tubular, centered on an axis (X-X), and which is provided with a central inlet (211) through which the material enters the interior of the casing to be pushed through the die, and - a core (220), which is coaxial with the casing and mounted rotatably about the axis relative to the casing, wherein the core (220) includes an upstream part (220.1) extending at least partially within the casing (210) such that a channel (230) is delimited between an inner surface (213A) of the casing and an outer surface (220A) of the core, said channel (230) having a cross-section which is annular and centered on the axis (X-X), wherein said channel includes an upstream end (230A) and a downstream end (230B) which are axially opposed to each other and between which material pushed through the die flows into the channel from the upstream end to the downstream end of the channel, and wherein the core (220) also includes a downstream part (220.2), extending outside the casing (210) and coupled to a motor-drive (250) of the die, suitable for driving the core in rotation about the axis (X-X), characterized in that the die (200) further includes a male divergent part (260) which is: - fixedly secured to the casing (210) and coaxially received inside the casing in such a way that, between the male divergent part and the casing, a passage (270) is delimited, through which the central inlet (211) of the casing and the upstream end (230A) of the channel (230) are connected and which is shaped in such a way that the material pushed through the die flows into the passage, from the central inlet of the casing toward the upstream end of the channel, forming a flow of material (6) which diverges from the axis (X-X) toward the downstream and is distributed around the axis, and - abutted axially to the upstream part (220.1) of the core (220), supporting and guiding the core in rotation.

2. The die according to claim 1 wherein the male divergent part (260) delimits an internal housing (261), which is separated from the passage (270) and wherein the upstream part (220.1) of the core (220) is received while being supported and guided in rotation.

3. The die according to claim 2, wherein the die (200) further includes a bearing (290), which is centered on the axis (X-X) and which is radially interposed between the upstream part (220.1) of the core (220) and a wall (262) of the male divergent part (260), delimiting the internal housing (261).

4. The die according to any of the preceding claims, wherein the passage (270) is delimited by an outer surface (260A) of the male divergent part (260) which is conical being centered on the axis (X-X) and diverging toward the downstream.

5. The die according to any of the preceding claims, wherein the casing (210) comprises a die sleeve (213) which delimits said inner surface (213A) of the casing, and wherein the casing (210) also includes a female divergent part (212): - which is fixedly secured to the die sleeve (213), - which is provided with the central inlet (211) of the casing, and - inside which the male divergent part (260) is fitted coaxially so as to delimit the passage (270) between the female divergent part and the male divergent part.

6. The die according to any of the preceding claims, wherein the male divergent part (260) is fixedly secured to the casing (210) by respective parts of the male divergent part and of the casing, one and / or the other of which are perforated in order to be crossed by said flow of material (6).

7. The die according to any of the preceding claims, wherein the male divergent part (260) includes a peripheral flange (263): - by means of which the male divergent is fixedly secured to the casing (210), - which extends, transversely to the axis (X-X), across said flow of material (6), and - which is traversed by the passage (270) via apertures (264) in the peripheral flange (263), which are distributed around the axis (X-X) and through which said flow of material (6) crosses the peripheral flange.

8. The die according to claims 6 and 7 taken together, wherein the peripheral flange (263) is axially caught between the die sleeve (213) and the female divergent part (212) of the casing (210).

9. The die according to any of the preceding claims, wherein the die (200) also includes a sealing member (294) designed to seal a mechanical rotating uncoupling interface between the male divergent part (260) and the core (220).

10. The die according to claim 9, wherein the sealing member (294) is: - received in a peripheral groove (223) of the upstream part (220.1) of the core (220), and - applied radially against a ring (266) of the male diverging part (260), the ring having an outer surface (266A) which is flush with said outer surface (220A) of the upstream part (220.1) of the core (220).

11. A system for the continuous preparation of an extruded food product (1), comprising: - a raw material (3) that is rich in proteins and in water, - an extruder (100) including at least one screw (120) and an extruder sleeve (110) inside which the at least one screw can be rotated so as to apply a thermomechanical processing to the raw material, and - a die (200), which is according to any of the preceding claims and the outer casing (210) of which is fixedly secured to the extruder sleeve (110) in such a way that, at the outlet of the extruder sleeve, the material is pushed by said at least one screw through the die via the central inlet (211) of the casing.