WO2007020345A2

WO2007020345A2 - Extruder comprising an adjustable gap and extrusion screw that can be exposed

Info

Publication number: WO2007020345A2
Application number: PCT/FR2006/001916
Authority: WO
Inventors: Emad Abdel Maaboud; Jean-Claude Doutrelon
Original assignee: Mdm
Priority date: 2005-08-16
Filing date: 2006-08-07
Publication date: 2007-02-22
Also published as: FR2889818A1; WO2007020345A3

Abstract

The invention relates to an extruder comprising an adjustable gap and extrusion screw that can be exposed. The inventive extruder (1) comprises at least one extrusion screw (2), a barrel (3) and an extrusion die (4), wherein the barrel (3) and the extrusion die (4) form an assembly which can move in relation to the extrusion screw (2) and which is guided in translation along an axis (D) which is essentially parallel to the longitudinal axis of the extrusion screw. The invention also comprises actuation means (6) which can move the barrel (3)/die (4) assembly in translation between a first operating configuration in which the extrusion screw (2) is housed inside the barrel (3) and a second open configuration in which the extrusion screw (2) is removed from the barrel (3). In the first operating configuration, the aforementioned actuation means (6) also enable the millimetric adjustment of the gap, i.e. of the position of the die (4) in relation to the extrusion screw (2) over a pre-defined small distance.

Description

EXTRUDER WITH ADJUSTABLE GUN AND EXTRUSION SCREW

discoverable

Technical area

The present invention relates to an improved new extruder, which can be used especially in the food industry.

Previous Art

In the agri-food industry, it is customary to manufacture by extrusion expanded products intended in particular for human food (for example biscuits, chips, cereal bars, etc.) or for animal feed (for example, animal feed from companies such as dogs, cats, ..., aquaculture food products, livestock feeds, in particular cattle, ovids, pigs, equines).

Generally, the expanded products are obtained by kneading, baking and extrusion in an extruder, of particulate material (s) based in particular on flour or semolina resulting from the grinding of cereals.

(soy, wheat, corn, rice, ...) or animals (eg fish meal, shrimp, ...).

By way of example, the international patent application WO01 / 72150 describes an installation comprising in series a preconditioner, an extruder, and a feed screw interposed between the preconditioner and the extruder. The extruder usually comprises at least one extrusion screw rotatably mounted inside a heating sleeve (for example sheath equipped with heating collars). Dry particulate matter (eg flour from the grinding of cereals or animals) or dry mix of particulate material (eg mixture of one or more flours and additive (s) in particulate form, eg vitamins, vitamin mineral supplements) is introduced into the preconditioner. If appropriate, one or more liquid or semi-liquid products (for example liquid nutritional supplement, fat, oil, dyestuff, materials of plant or animal origin). Water and, if appropriate, water vapor are also introduced into the conditioner.

The mixture in the preconditioner is intensely kneaded and partially cooked. At the outlet of the conditioner, a homogeneous mixture is obtained which is then introduced into the extruder either directly or by means of a feeding device. Preferably, but not necessarily, it implements a twin-screw extruder comprising two co-rotating and co-penetrating parallel rotating screws. Under the action of heat, pressure and shear, the material, as it progresses in the extruder, expands and cooks. When the operation of the extruder is stabilized (after the initial start-up phase), an extruded final product is obtained at the outlet of the extruder in the form of a continuous and shaped strand whose cross-section is given by the exit section of the extruder die. This expanded bead is then cut into products of predefined length anywhere appropriate cutting line.

When using an extruder, it is essential to be able to adjust and control the quality of extruded products, including their density. To allow this adjustment, it is necessary to finely adjust the size of the space between the head of the extrusion screw and the extrusion die. Japanese Patent Application JP03262471, for example proposes a technical solution for adjusting the distance (commonly referred to as "air gap") separating the head of the extrusion screw and the extrusion die. This solution is based on the implementation of short cylinders (referenced (9) in Figures 1 and 2 of JP03262471) and mounted in the rear portion of the sheath of the extruder.

To carry out maintenance operations (especially cleaning or checking), modification, repair or replacement of the extrusion screw or screws, it is also necessary to have access to the extrusion screw (s) housed inside the sheath. For this purpose, with an extruder such as that described for example in the aforementioned publication JP03262471, one is forced to manually remove and remove the sleeve in order to completely disengage the extrusion screw or screws. On the one hand, this requires a heavy manual intervention. On the other hand, one is prejudiced to wait for the cooling of the screw and the sheath before any intervention.

European Patent Application EP 0 385 853 discloses an extrusion screw equipped with actuating means (slide 8 and cylinder 11), which are used only to disengage the screw from its sheath or to cover the extrusion screw with the scabbard. These actuating means do not allow fine adjustment of the position of the sleeve relative to the extrusion screw, and in particular a millimeter adjustment of the gap of the extruder. More particularly, it is explained in this publication (passage of column 2, line 58) that the extruder comprises "means of longitudinal and successive displacement of the sheath 6 and the slide S", which means that these means allow to move successively the sheath then the slide (or vice versa). This is confirmed by the explanation of the operation of these displacement means in the passages of column 3, lines 20 to 58 and column 4, lines 1 to 3.

Objective of the invention

The main object of the present invention is to propose a new extruder, in particular that can be used in the food industry, which allows both a quality adjustment of the extruded products and an easy and quick access to the extrusion screw (s), in particular during maintenance operations or modification or replacement of said extrusion screw (s).

SUMMARY OF THE INVENTION The subject of the invention is thus an extruder which, in known manner, comprises at least one extrusion screw, a sleeve and an extrusion die. The sheath and the extrusion die form an assembly that is movable relative to the extrusion screw and is guided in translation along an axis (D) substantially parallel to the longitudinal axis (A) of the extrusion screw . According to a first aspect of the invention, the extruder comprises actuating means which make it possible to move the sheath / die assembly in translation between a first configuration, known as a work configuration, in which the extrusion screw is housed in the housing. inside the sheath, and a second configuration, called open, in which the extrusion screw is disengaged from the sheath, and the actuating means further allow in the first working configuration an adjustment at least millimeter of the position of the die relative to the extruder screw over a short distance (d) predefined.

More particularly, according to this first aspect, in a particular variant embodiment, the actuating means comprise a first bidirectional linear actuator for translating the sheath / die assembly in translation between the first working configuration and the second open configuration, and a second bidirectional linear actuator for at least millimetric adjustment of the position of the die.

According to a second aspect of the invention, the extruder comprises actuating means which comprise at least a first bidirectional linear actuator for translating the sheath / die assembly in translation between a first configuration, called a work configuration, in which the screw extrusion is housed inside the sleeve, and a second configuration, called open, in which the extrusion screw is disengaged from the sleeve, and at least a second bidirectional linear actuator for fine adjustment of the position of the die relative to the extruder screw over a short distance (d) predefined. More particularly, according to this second aspect, in a particular variant embodiment, the second linear actuator Bidirectional allows at least a millimetric adjustment of the position of the die with respect to the extrusion screw.

More particularly, the extruder of the invention has the following additional and optional features, taken separately or, if appropriate, in combination:

the first actuator is a two-position cylinder;

the first actuator is a hydraulic, pneumatic or electrical cylinder; the second actuator is a millimeter cylinder. the second actuator is a hydraulic or electric cylinder;

- The first and second actuators are constituted by two linear cylinders mounted in opposition;

- In an alternative embodiment, the actuating means comprise a plate which is movable relative to the extrusion screw and guided in translation, and on which is mounted the sheath / die assembly;

- Preferably, the extruder comprises a cutting device which is mounted at the die outlet, and which is movable in translation with the sleeve / die assembly. Description of figures

Other features and / or advantages of the invention will appear more clearly on reading the detailed description below of a preferred embodiment of an extruder of the invention.

This detailed description is given by way of nonlimiting and non-exhaustive example of the invention, and with reference to the appended drawings in which:

FIG. 1 is a side view of an extruder of the invention, the sheath / die assembly being in the so-called working configuration,

FIG. 2 is a side view of the extruder of the invention, the sheath / die assembly being in the so-called open configuration,

FIG. 3 is a view from above of the extruder of FIG. 1, FIG. 4 is a view from above of the extruder of FIG. 2,

FIG. 5 is a detailed view of the space separating the head of the screws and the extrusion die, in the working configuration of the extruder, said space being adjusted with a minimum air gap; FIG. a detailed view of the space separating the head of the screws and the extrusion die, in the working configuration of the extruder, said space being adjusted with a maximum gap,

- Figure 7 is a diagram of the actuating means for moving the sleeve assembly / extrusion die. detailed description

FIGS represented in the figures an extruder 1 that can be used in the food industry for the continuous manufacture of food products based in particular and for example flour from the grinding of cereals or animals. Said extruder 1 may for example (but not exclusively) be used in an installation of the type described in publication WO 01/72150, and comprising, upstream of the extruder, means for feeding and preparing the material to be extruded. (In particular preconditioner and possibly feed screw). With reference to FIGS. 1 and 3, the extruder 1 comprises in a usual manner per se:

two co-rotating and co-penetrating extrusion screws 2, whose longitudinal axes (A) are substantially parallel, a heating sleeve 3 comprising mainly a substantially cylindrical tubular element 30 intended to receive the extrusion screws 2, and equipped with on its outer periphery of heating collars 31 or any other equivalent heating means,

an extrusion die 4 which is fixed to the front end of the tubular element 30 of the sleeve 3, and which, in the particular example illustrated, comprises a convergent 41 which, during extrusion, guides the material so that two screws 2, - Motorized means 5 (geared motor and kinematic chain of associated motion transmission) for rotating at a controlled speed, the two extrusion screws 2 along their longitudinal axis (A). The novelty of the extruder 1 of the accompanying figures lies in the implementation of the actuating means 6 of the sheath 3 / die assembly 4, a particular example of structure and operation will now be detailed.

The extrusion screws 2 and the sheath 3 are fixed on a plate 60, by means of supports 61. This plate 60, and by the same assembly sheath 3 / die 4 embedded, is movable in translation relative to the extrusion screws 2, along an axis D parallel to the longitudinal axes (A) of the extrusion screws 2, and between two extreme positions:

a first extreme position corresponding to the working configuration of FIGS. 1 and 3,

a second extreme position corresponding to the open configuration of FIGS. 2 and 4.

The movable plate 60 is guided in translation along the axis D with respect to the fixed frame B of the extruder 1, in particular by means of rollers 62 mounted free to rotate.

To allow the translational movement of the movable plate 60 and the sleeve assembly 3 / die 4 on board, the actuating means 6 comprise two cylinders 64 and 65 in opposition. The jack 64 is a bidirectional linear hydraulic cylinder with two positions (jack type all or nothing) and long stroke. The jack 65 is a bidirectional linear hydraulic cylinder of millimeter type and short stroke. The body 64a of the jack 64 is fixed to the carrier frame B, below the level of the movable plate 60. The jack 65 is embedded on the movable plate 60, the body 65a of this jack 65 being fixed on the lower face of the movable plate 60 The two rods 64b and 65b of the two jacks 64 and 65 are attached end to end by means of a coupling sleeve 66. The jack 65 makes it possible to control a bidirectional and millimetric displacement of the sheath 3 / die assembly 4, when said sheath 3 / die assembly 4 is in the working configuration [see below air gap adjustment (d)]. The jack 64 makes it possible to control a bidirectional displacement over a long stroke of the sheath 3 / die assembly 4 between the working configuration of FIGS. 1 and 3 and the open configuration of FIGS. 2 and 4.

More particularly, with reference to FIG. 7, the control means 67 of the two jacks 64 and 65 mainly comprise a hydraulic circuit comprising:

an oil reservoir 670 for supplying oil to the two cylinders 64 and 65,

a gear pump 671 controlled by an electric motor 672 and making it possible to supply oil in parallel with a solenoid valve 673 for controlling the jack 64 and a servo-distributor 674 for controlling the jack 65,

between the pump 671 and the two cylinders 64 and 65, a pressure gauge 675a isolated by a valve 675b, a non-return valve 675c, a pressure filter 675d, a 675e pressure switch with a digital display, an oleopneumatic accumulator 676 which is associated with a manually operated safety block 677, which makes it possible to mitigate any leaks in the hydraulic circuit of the jack 65 by maintaining a constant oil pressure in the chamber of the jack 65 when the latter is adjusted in position. Also to control in position the rod 65b of the jack 65, the control means 67 comprise an electric control circuit which is associated with the jack 65, and which mainly comprises:

detection means 678 of the instantaneous position of the rod 65b, which detection means deliver a detection signal 678a which encodes the instantaneous position of the rod 65b of the jack 65, a comparator 679 which receives as input the detection signal

678a above and a reference signal Sc issued by a control automation (not shown) and coding the desired adjustment position for the rod 65a of the cylinder 65, said comparator 679 outputting an error signal 679a depending on the difference between the detection signal 678a and the set signal Sc; this error signal 679a allows the adjustment by the distributor 674 of the desired positioning for the rod 65b of the cylinder 65. Adjustment of the air gap (d)

With reference to FIG. 6, the distance (d) measures the distance between the rear face 41a of the die 4 and the free end before 2a of the extrusion screws 2, when the sheath 3 / die assembly 4 is in the working configuration. This gap (d) is commonly called gap. In FIG. 6, the gap (d) is set to a maximum value (d _max ); in FIG. 5, the gap (d) is set to a minimum value (d _m j _n ). The maximum and minimum values (d _max) and (d _m j _n) to the gap (d) of the extruder 1 are predefined parameters. For example, and without limitation of the invention, d _max is 13 mm and _m j _n is 1 mm, which corresponds to a Dd adjustment range of 12mm to the gap (d).

The adjustment of the gap value (d) between the two maximum (d _max ) and minimum (d _m j _n ) predefined values depends on the extruded product, and conditions the quality of this product, in particular its density. It will therefore be advantageously adjusted case by case depending on the extruded product.

When the sleeve assembly 3 / die 4 is in the working configuration (FIG. 1), the adjustment of the value of the air gap (d) between the two predefined limits (d _ma χ) and minimum limits (d _m i _n ) is achieved with millimetric precision by means of the jack 65, the final position of the rod 65b of the jack 65 being parameterized by means of the aforementioned setpoint signal Sc.

When the rod 65b of the jack 65 is moved towards the rod 64b of the other cylinder 64 (Figure 1 / arrow E1), it is supported on the fixed rod

64b of the cylinder 64 and the cylinder 65 pushes in a millimetric way the entire plate 60 / sleeve 3l / die 4 in the opposite direction (Figure 1 / arrow

E2), which results in increasing the value of the gap (d). Conversely, when the rod 65b of the jack 65 is moved in the opposite direction (FIG. 1 / arrow E2), the jack 65 exerts a pull on the plate assembly

60 / sleeve 3 / die 4 and millimetrically moves this assembly in the opposite direction (Figure 1 / arrow E1), which results in decreasing the value of the air gap (d). Once the air gap (d) has been adjusted to millimeter accuracy by means of the cylinder 65, the extruder 1 can be used to extrude the product. During extrusion, it is possible to control the quality of the extruded product, and to adjust, with millimeter precision, the air gap (d) by means of the cylinder 65. Opening / closing the extruder

When the operator wishes to access the extrusion screws 2, for example to carry out cleaning, checking, modification or replacement operations on these screws, he actuates the movable plate 60 by means of the jack 64 (displacement of the rod 64b of the cylinder in the direction of the arrow O of Figure 1), so as to bring the on-board assembly sheath 3 / die 4 in the open configuration of Figures 2 and 4.

In the open configuration of Figures 2 and 4, the extrusion screws 2 are discovered and easily accessible by an operator. The use of the jack 64 advantageously facilitates the withdrawal operations of the sheath assembly 3 / die 4 (open configuration) and implementation of this assembly on the extrusion screws 2 (working configuration). Also, the use of the jack 64 advantageously makes it possible to discover the extrusion screws 2 without having any contact with the sheath 3. It is therefore possible to discover the extrusion screws 2 by removing the sheath assembly 3 / die 4 without waiting for the sheath 3 to cool, which decreases advantageously the response times.

When the operator wants to restart the extruder

1, it repositioned by means of the cylinder 64 the sheath 3 / fielder 4 assembly with respect to the extrusion screws, by moving the rod 65b of the cylinder in the direction of the arrow F of FIG. 2 to bring the assembly scabbard

3 / box 4 in the working configuration of FIG.

Preferably, in the example illustrated in the accompanying figures, the extruder 1 comprises, at the outlet of the die 4, a cutting device 7, which allows in operation to cut the continuous coil of expanded product from the extrusion die 4, in the form of expanded products of smaller dimensions. The cutting system 7 is known per se and can be of any known type. In particular it may consist of a cutting system using a rotary cutting wire or by means of one or more cutting blades, or a water jet cutting system. The novelty of the implementation of this cutting device 7 lies in the fact that it is embedded and fixed on the movable plate 60, so that during the opening operation of the extruder, the device of cutout 7 is spaced apart from the extrusion screws 2, at the same time as the sleeve 3 / fielder assembly 4. The invention is not limited to the implementation of the two hydraulic cylinders 64 and 65 above, which can be replaced by any actuator or equivalent set of actuators performing the same function. By way of non-exhaustive examples, the jack 64 may also be a pneumatic or electric cylinder. The millimeter cylinder 65 can also be an electric cylinder. Also each cylinder 64 65 can be replaced by an equivalent linear actuator and for example by a rack / gear assembly controlled by a motor or geared motor. When the cylinder 65 is replaced by another type of linear actuator, it is important that this actuator allows a displacement of the sheath 3 / die assembly 4 with a millimetric precision when the assembly is in the working configuration. Also, the invention is not limited to a twin-screw extruder, but can be implemented on any extruder comprising at least one extrusion screw 2.

Claims

An extruder (1) comprising at least one extrusion screw (2), a sleeve (3), and an extrusion die (4), characterized in that the sleeve (3) and the extrusion die ( 4) form an assembly which is movable with respect to the extrusion screw (2) and which is guided in translation along an axis (D) substantially parallel to the longitudinal axis (A) of the extrusion screw, in that it comprises actuating means (6) which make it possible to translate the sleeve (3) / die assembly (4) in translation between a first configuration, called a working configuration, in which the extrusion screw (2) is housed inside the sheath (3), and a second configuration, called open, in which the extrusion screw (2) is disengaged from the sheath (3), and in that the actuating means (6) allow in addition, in the first working configuration, at least a millimetric adjustment of the position of the die (4) with respect to the extrusion screw (2) over a short distance ( d) predefined.

2. Extruder according to claim 1 characterized in that the actuating means (6) comprise a first bidirectional linear actuator (64) for translational movement of the sleeve assembly (3) / die (4) between the first working configuration and the second open configuration, and a second bidirectional linear actuator (65) for setting at least millimetric the position of the die (4).

3. Extruder according to claim 2 characterized in that the first actuator (64) is a cylinder with two positions.

4. Extruder according to claim 2 or 3 characterized in that the first actuator (64) is a hydraulic cylinder, pneumatic or electric.

5. Extruder according to claim 2 characterized in that the second actuator (65) is a millimeter cylinder.

6. Extruder according to claim 5 characterized in that the second actuator (65) is a hydraulic or electric cylinder.

7. Extruder according to one of claims 2 to 6 characterized in that the first and second actuators are constituted by two linear cylinders (64, 65) mounted in opposition.

8. Extruder according to one of claims 1 to 7 characterized in that the actuating means (6) comprise a plate (60) which is movable relative to the extrusion screw (2) and guided in translation, and on which is mounted the sleeve assembly (3) / die (4).

9. Extruder according to one of claims 1 to 8 characterized in that it comprises a cutting device (7) which is mounted at the die outlet (4), and which is movable in translation with the sleeve assembly (3). ) / die (4).

10. Extruder according to claims 8 and 9 characterized in that the cutting device (7) is fixed on the movable plate (60).

Extruder (1) comprising at least one extrusion screw (2), a sleeve (3), and an extrusion die (4), characterized in that the sleeve (3) and the extrusion die ( 4) form an assembly which is movable with respect to the extrusion screw (2) and which is guided in translation along an axis (D) substantially parallel to the longitudinal axis (A) of the extrusion screw, in that it comprises actuating means (6) which comprise at least a first bidirectional linear actuator (64) for translating the sleeve (3) / die assembly (4) in translation between a first configuration, called a working configuration, in which the extrusion screw (2) is housed inside the sheath (3), and a second configuration, called open, in which the extrusion screw (2) is disengaged from the sheath (3), and at least a second bidirectional linear actuator (65) for adjusting the position of the die

(4) with respect to the extrusion screw (2) over a short distance (d) predefined.

12. Extruder according to claim 11, characterized in that the second bidirectional linear actuator (65) allows adjustment at least millimetric of the position of the die (4) relative to the extrusion screw (2).

13. Extruder according to claim 11 or 12 characterized in that the first actuator (64) is a cylinder with two positions.

14. Extruder according to one of claims 11 to 13 characterized in that the first actuator (64) is a hydraulic cylinder, pneumatic or electric.

15. Extruder according to claim 12 characterized in that the second actuator (65) is a millimeter cylinder.

16. Extruder according to claim 11 or 12, characterized in that the second actuator (65) is a hydraulic or electric cylinder.

17. Extruder according to one of claims 11 to 16 characterized in that the first and second actuators are constituted by two linear cylinders (64, 65) mounted in opposition.

18. Extruder according to one of claims 11 to 17 characterized in that the actuating means (6) comprise a plate (60) which is movable relative to the extrusion screw (2) and guided in translation, and on which is mounted the sleeve assembly (3) / die

(4).

19. Extruder according to one of claims 11 to 18 characterized in that it comprises a cutting device (7) which is mounted at the die outlet (4), and which is movable in translation with the sleeve assembly (3). ) / die (4).

20. Extruder according to claims 18 and 19 characterized in that the cutting device (7) is fixed on the movable plate (60).