WO2021044449A1

WO2021044449A1 - Extrusion device

Info

Publication number: WO2021044449A1
Application number: PCT/IT2019/000068
Authority: WO
Inventors: Simone Maccagnan
Original assignee: Gimac Di Maccagnan Giorgio
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2021-03-11

Abstract

An extrusion device comprises a tubular body (2) which internally defines an extrusion duct, a worm screw (3) inserted in the extrusion duct and a containment body (4) suitable to contain a material to be extruded. The containment body (4) is configured to rotate around a rotation axis inclined with respect to a main development axis of the tubular body (2).

Description

DESCRIPTION EXTRUSION DEVICE

The present invention relates to the field of systems for manufacturing objects by means of extrusion processes, at the same time, the present invention relates to an extrusion device.

In the field of extrusion processes, a fundamental aspect is represented by the need to adequately process polymers that have very different characteristics from each other, or that require particular attention in being processed.

In particular, it is necessary to have extrusion devices that have operating parameters, such as working temperatures and extrusion speed, such as to prevent the material from deteriorating during its processing, e.g. thickening too much because it is not adequately fluidized or burning by caking on the walls of the device.

Both the situations outlined above by way of example involve long machine downtimes to carry out a complete removal of the deteriorated material, as well as the waste of considerable quantities of raw materials. This problem becomes particularly evident when the extrusion process involves the use of adhesive materials, such as, e.g., hot melt glues, as in addition to the normal need to provide operating parameters able to guarantee the fluidity of the material, it becomes further important to also take into account its inherent adhesiveness characteristics.

In this context, the technical task underlying the present invention is to propose an extrusion device that overcomes at least some of the drawbacks of the known art mentioned above.

Particularly, it is an object of the present invention to provide an extrusion device able to correctly operate without the risk of deterioration of the material to be extruded, particularly when such material has particular viscosity and/or adhesiveness characteristics.

The technical task mentioned and the objects stated are substantially achieved by an extrusion device comprising the technical features set out in one or more of the appended claims.

According to the present invention, an extrusion device is shown which comprises a tubular body, a worm screw and a containment body.

The tubular body internally defines an extrusion duct and has a first end, which in turn defines an inlet for a material to be extruded, and a second end which instead defines an outlet nozzle for the material to be extruded. The worm screw is partially inserted in such extrusion duct and is configured to promote the extrusion of the material to be extruded moving it between the first and second ends crossing the extrusion duct. The containment body defines a containment volume suitable to contain the material to be extruded and is configured to rotate around an inclined rotation axis with respect to a main development axis of the tubular body. Moreover, the containment volume has a coupling opening facing the first end of the tubular body to transfer the material to be extruded inside it to the extrusion duct.

Advantageously, the device of the present invention overcomes the problems highlighted in the known art, since the continuous movement of the material inside the containment body guarantees its fluidity, preventing its condensation and adhesion with the walls of the containment volume. Preferably, the worm screw comprises a first threaded portion inserted inside the containment volume and a second threaded portion inserted inside the tubular body and extending between the first end and the second end so as to promote the movement of the material to be extruded along the entire extrusion duct. Preferably, the first threaded portion of the worm screw is placed in contact with a side surface of the containment volume, so that during use such side wall slides against a thread of the worm screw.

If the needs of the moment make it necessary or appropriate, the first threaded portion of the worm screw can also be adjacent to a portion without thread: such portion without thread, placed at a suitable height inside the containment body, would act as "calendering means" operating on the substances inserted in the containment body itself.

Preferably, the containment volume has a frustoconical shape, wherein the smaller base defines the coupling opening.

According to a preferred embodiment, the containment body is configured to rotate in the opposite direction with respect to a rotation direction of the worm screw.

Advantageously, the first end has a front edge inclined with respect to the main development axis of the tubular body, so as to define an inclined seat.

Preferably, the containment body is at least partially inserted in such inclined seat.

Preferably, the inclined seat is shaped complementarily to a respective insertion portion of the containing body, according to such aspect the insertion portion defines the coupling opening.

Preferably, the device comprises sealing means interposed between the containment body and the tubular body such as to allow rotation of the containment body with respect to the tubular body, preventing the material to be extruded to leak out from the extrusion device.

Advantageously, the containment body has an outer surface which can be coupled to motion transmission means.

According to a preferred embodiment, the outer surface has a grooved profile such as to define a sprocket which can be coupled with a chain, a belt, a gear or another means for transmitting the motion.

Advantageously, the extrusion device further comprises thermoregulating means active on the tubular body and/or on the containment body so as to adjust an extrusion temperature of the device.

Preferably, such thermoregulating means comprise at least one sleeve fitted around the tubular body.

Advantageously, the thermoregulating means can be made by a thermal bath and/or by one or more resistors.

Further characteristics and advantages of the present invention will become more apparent from the description of an exemplary, but not exclusive, and therefore non-limiting preferred embodiment of an extrusion device, as illustrated in the appended drawings, in which:

- Figure 1 shows a sectional view of the extrusion device according to the present invention;

- Figure 2 shows a perspective view of the device of Figure 1 ;

In the attached Figures, the reference number 1 relates to an extrusion device according to the present invention, which will be referred simply as a device 1 in the following description.

The device 1 of the present invention comprises a tubular body 2, a worm screw 3 and a containment body 4.

The tubular body 2 internally defines an extrusion duct and has a first end 2a, which defines an inlet for a material to be extruded, and a second end 2b which instead defines an outlet nozzle for the material to be extruded. For the purposes of the present description, the generic term "material to be extruded" refers to any known material suitable to be used in the field of extrusion processes, for example plastics, polymers or other materials. Particularly, all those materials of the extrusion process field which are inhomogeneous in terms of size or morphological distribution and/or which are intended to make glues or adhesives are to be considered as included in the terminology of materials to be extruded.

By way of non-limiting example, the inhomogeneous materials in terms of size distribution can comprise powders mixed with pellets and/or pellets with a diameter typically between 2 mm and 15 mm.

According to the invention, the newly introduced granulometry or diameter interval must not be considered as limiting the operational applications of the device 1: e.g., the device 1 itself can work to feed/mix/extrude powdered or granulated materials or materials available in the aggregation state in the form of so-called "pellets" or similar corpuscles having average dimensions of less than 2 mm and/or greater than 15 mm (which typically is the typical granulometry of low-melting adhesives/giues and waxes), or more in general still in different forms such as, e.g., pieces in the form of "bar of soap" or "ingot" or "large pieces" or "large scales".

Always by way of example, the inhomogeneous materials in terms of morphological distribution can comprise powders, pellets, lenticular granules, scales, flakes, etc.

Similarly, the materials of the glue and/or adhesive type can comprise compounds such as: ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), hot-melt type glues, etc.

Generally, such materials are fed to the device 1 in the form of discrete elements and subsequently, by means of suitable heating processes brought to completion during their transit along the extrusion duct, they are brought into a fluid configuration which allows their application upon suitable supports/products or modelling to make semi-finished and finished products.

The worm screw 3 is partially inserted inside such extrusion duct and is configured to promote the extrusion of the material to be extruded moving it between the first end 2a and the second end 2b.

Particularly, the worm screw 3 performs the dual function of moving the material to be extruded and assisting its passage in a fluid configuration, particularly increasing its temperature by means of the friction force generated during the sliding of the material to be extruded along the extrusion duct.

The worm screw 3 also performs a mixing function which assists the generation of a continuous flow of fluid product starting from the discrete elements which make up the material to be extruded when it is fed to the device 1.

As will be described in greater detail below, the worm screw 3 is only partially inserted inside the extrusion duct, particularly the worm screw 3 is coupled to the tubular body in such a way as to be partially protruding beyond the first end 2a.

The containment body 4 defines a containment volume 4a suitable to contain the material to be extruded and is configured to rotate around an inclined rotation axis "R" with respect to a main development axis "X" of the tubular body 2.

In this way, during use of the device, the material to be extruded is subjected to a continuous movement which prevents its static adhesion to the walls of the containment volume 4a.

Moreover, the containment volume 4a has a coupling opening 4b facing the first end 2a of the tubular body 2 to transfer the material to be extruded to the extrusion duct.

In other words, the first end 2a and the coupling opening 4b are interfaced to allow the passage of the material to be extruded from the containment volume 4a to the tubular duct.

In detail, the containment body 4 is coupled to the tubular body 2 and is preferably in contact with it, so as to provide a continuous and uninterrupted path for the material to be extruded which starts from the containment volume 4a and, passing through the first end 2a, passes through the entire extrusion duct, until it ends at the second end 2b of the tubular body 2.

To promote the mutual coupling between the tubular body 2 and the containment body 4, the first end 2a has a front edge inclined with respect to the main development axis "X" of the tubular body 2.

In this way, the first end 2a defines an inclined seat inside which the containment body 4 is at least partially inserted.

Particularly, the containment body 4 has a lower portion shaped complementarily to a respective recess formed in the first end 2a, so as to provide a shape coupling which guarantees the stability of the device, especially during its use.

Advantageously, the inclined seat also provides a feedback point which allows the inclination of the rotation axis "R" of the containment body 4 to be determined precisely and to keep such inclination constant over time.

In fact, according to the shape and the dimensions of the containment body 4 it is possible to realize an inclined seat which has structural characteristics such that the insertion inside it of the lower portion of the containment body 4 is possible only by inclining it, until bringing its rotation axis "R" to form the desired angle with respect to the main development axis "X" of the tubular body 2.

Preferably, the device comprises sealing means interposed between the lower portion of the containment body 4 and the inclined seat, so as to allow rotation of the containment body 4 with respect to the tubular body 2 while preventing the undesired leak out of the material to be extruded from the path defined by the containment volume 4a and the extrusion duct.

Particularly, such sealing means can comprise one or more bearings and/or gaskets.

According to a preferred embodiment, the worm screw 3 comprises a first threaded portion 3a inserted in the containment volume 4a and a second threaded portion 3b which extends from the first end 2a of the tubular body 2 to its second end 2b.

Particularly, the first threaded portion 3a is in contact with a side surface of the containment volume 4a.

In this way, when the device 1 is in use, the side surface of the containment volume 4a slides on the first threaded portion 3a.

Such particular structural conformation makes it possible to further promote the detachment of the material to be extruded from the side surface of the containment chamber 4a, since during the rotation of the containment body 4 the worm screw 3 acts mechanically on it removing the material to be extruded that adhered to it.

According to a preferred embodiment, shown in the attached figures, the containment volume 4a has a substantially frustoconical shape and the coupling opening is defined by a smaller base of the containment volume 4a.

More in detail, the containment volume 4a has a frustoconical shape wherein the smaller base is arranged below and faces directly on the first end 2a, while the larger base, facing upwards, defines an inlet opening through which it is possible to feed the material to be extruded to the containment volume 4a.

In other words, the containment volume 4a has a substantially funnel-like shape, which allows the material to be extruded to be easily introduced, and at the same time conveying it and guiding it inside the extrusion duct through the first end 2a of the tubular body 2.

Advantageously, the containment body 4 is configured to rotate according to an opposite direction with respect to a rotation direction of the worm screw 3.

In this way the containment body 4 turns out to be counter-rotating with respect to the worm screw 3, which therefore crawls against the side surface of the containment volume 4a, thus optimizing the mechanical action of removing the material to be extruded which has adhered to such side surface.

Advantageously, the various components of the device 1 which can be moved have portions configured to be coupled with suitable motion transmission means.

Particularly, in accordance with a particular embodiment not shown in the attached figures, the containment body 4 has an external surface which can be coupled to motion transmission means.

Such outer surface can for example have a grooved profile which substantially makes a sprocket, which can be therefore coupled for example with a chain, a belt, a gear or another motion transmission means.

Particularly, the motion transmission means responsible for the rotational movement of the containment body 4 can be connected with the same power source, or can be connected to respective separate power sources, suitably dedicated and arranged for moving the individual components of the device 1. The device 1 further comprises thermoregulating means 5 which are active on the tubular body 2 and/or on the containment body 4 so as to adjust an extrusion temperature of the device 1.

In other words, to promote the passage of the material to be extruded into the fluid configuration, there are suitable thermoregulating means 5 which can be active on the entire device or only on some of its parts, depending on the characteristics of the material to be extruded which must be processed.

Such thermoregulating system 5 therefore synergically contributes to the action of the worm screw 2 in increasing the temperature of the material to be extruded, promoting the generation of a continuous and homogeneous flow of material to be extruded, which can then be correctly fed to the production processes placed downstream of the device 1.

Particularly, the thermoregulating system 5 comprises at least one sleeve fitted around the tubular body 2.

Preferably, the sleeve is applied on the tubular body 2 so as to cover it integrally from the first end 2a to the second end 2b.

Alternatively, the thermoregulating system 5 comprises a plurality of sleeves applied on the tubular body 2 so as to cover it integrally from the first end 2a to the second end 2b.

Advantageously, each sleeve can be individually controlled, i.e. the extrusion temperature of the device 1 can be controlled in a particularly accurate manner by varying the temperature of individual portions of the extrusion duct, even independently.

Particularly, each sleeve can comprise a plurality of channels formed inside its side surface in such a way as to allow the passage, e.g., of a thermoregulating fluid or an electric resistor able to generate heat by Joule effect.

Advantageously, the present invention achieves the proposed aims by overcoming the drawbacks of the prior art by providing the user with an extrusion device which ensures a correct processing of the material to be extruded, preventing it from deteriorating and sticking to the walls of the containment volume, particularly if such material to be extruded is particularly adhesive as it is intended to make a glue.

The present invention also allows a wide variety of applications in combination with various types of materials: in addition to the aforementioned use for glues/adhesives, the present device can also be used to disperse various types of polymeric ingredients, such as different dyes, additives and polymers (this possibility occurs thanks to the fact that, if necessary, the melting process can be started in the containment body 4 with a frustoconical shape, which, thanks to the rotation, can pre-mix a pre-melted amalgam of various components before entering the underlying part of the device itself) or also by extrusion/feeding/pumping of rubbers, silicones, muds, creams, jams, soaps, fats, liquids and fluids with very high viscosity.

To further increase the operational flexibility of the present device, the containment body 4 can be associated with suitable pre-heating means (by irradiation, by projection of infrared rays, by conduction or even by electric induction, according to the needs of the moment).

Still from the point of view of the possible optional structural additions, the fact that the frustoconical containment body 4 is subjected to an "orbital rotation" can be combined with the presence of suitable mechanical homogenization means operating inside the frustoconical cavity: such mechanical homogenization means, which for example can consist of a doctor blade or a comb suitably arranged in the cavity itself, allow the introduction of polymer blocks even of relatively "great" dimensions with respect to the frustoconical cavity, allowing a gradual movement thereof and at the same time allowing the melting part of these blocks to flow towards the tubular body 2 specifically designed for extrusion/feeding/pumping.

It should also be noted that the effect of the "orbital rotation" of the containment body 4 favours the thermal uniformity of the entire device 1 , giving a more homogeneous thermal profile inside the polymer being processed as well as optimizing the dispersion of the fluidized or melted components.

Claims

1 . Extrusion device comprising:

- a tubular body (2) internally defining an extrusion duct and having a first end (2a) defining an inlet of a material to be extruded, and a second end (2b) defining an outlet nozzle of said material to be extruded;

- a worm screw (3) partially inserted in said extrusion duct;

- a containment body (4) defining a containment volume (4a) suitable to contain the material to be extruded and having a coupling opening (4b) facing the first end (2a) to transfer the material to be extruded to the extrusion duct, said containment body (4) being configured to rotate around a rotation axis (R) inclined with respect to a main development axis (X) of the tubular body (2).

2. Device according to claim 1, wherein the worm screw (3) comprises a first threaded portion (3a) inserted in the containment volume (4a) and a second threaded portion (3b) extending from the first end (2a) to the second end (2b) of the tubular body (2).

3. Device according to claim 2, wherein the first threaded portion (3a) is in contact with a side surface of the containment volume (4a).

4. Device according to one or more of the preceding claims, wherein the containment volume (4a) has a frustoconical shape, said coupling opening (4b) being defined by a smaller base of the containment volume (4a).

5. Device according to one or more of the preceding claims, wherein the containment body (4) is configured to rotate according to an opposite direction with respect to a rotation direction of the worm screw (3).

6. Device according to one or more of the preceding claims, wherein the first end (2a) has a front edge inclined with respect to the main development axis (X) of the tubular body (2) so as to define an inclined seat, said containment body (4) being at least partially inserted in said inclined seat.

7. Device according to one or more of the preceding claims, wherein the containing body (4) has an outer surface which can be coupled to motion transmission means.

8. Device according to claim 7, wherein said outer surface has a grooved profile, preferably suitable to define a sprocket.

9. Device according to one or more of the preceding claims, comprising thermoregulating means active on the tubular body (2) and/or on the containment body (4) so as to adjust an extrusion temperature of the device.

10. Device according to claim 9, wherein the thermoregulating system (5) comprises at least one sleeve fitted around the tubular body (2).