EP0865889B1 - Device for making ceramic articles - Google Patents

Abstract

The industrial-scale machine is used for manufacturing ceramics. It has at least one screw mixer (1,5,6) connected to a unit for degassing the mixed material. The degassing unit (2) has at least one chamber (21) connected to a vacuum pump and cutters (9,10) for fragmenting the material. The degassing unit is connected to a screwed (4,13) extruder (3) conveying the material to a stock and die. The chamber of the degassing unit includes a screw (4,7) organised around an axis common with the axis of the screws (4-6) of the mixer and the screws of the extruder. This axis is made up of a single fully rotating shaft mounted out-of-true from a motor reducer driving the shaft up to the die-carrying limb. The shaft carries an assembly of wear pieces of the installation, mounted so that they can be detached from the shaft.

Description

The present invention relates to an installation for manufacturing on an industrial scale of ceramics, such as bricks, tiles or the like.

Installations for the manufacture of ceramics, still called vacuum stretching groups or incorporated degasser mixer, are widely used, especially in brickyards. The principle of operation of such known installations, one of which example is shown in Figure 1, is as follows. The material to be profiled, for example clay in the case of brick making, is continuously introduced into the trough of a mixer fitted with one or more shafts rotary propellers 30 which pass the clay through a grid 31. This grid aims to stop possibly impurities, reduce the clay itself in fragments most often in the form of drawn filaments, but essentially ensuring the seal between the mixer and the vacuum chamber. The the purpose of wire drawing is to facilitate a subsequent degassing of the clay. Indeed, the clay coming out of the grid in the form of filaments falls to the bottom of a sealed vacuum chamber 34 which it crosses using 32 diggers who break and transfer the clay up a screw extruder 33 capable of passing the clay to through appropriately profiled dies according to the desired shape of the final extruded product. Clay, having crossed continuously and in fragments dimensionally irregular the vacuum chamber 34 is deprived of much of the air it contained. This degassing makes it possible to obtain products extruded from a better and more consistent quality. It is to highlight that the tightness of the chamber 34 at the level of the shaft is provided by lip seals shown in 35.

Such an installation is shown partially in view from above in Figure 1 and is described in part in the Patent FR-A-2,252,739. The problem of such facilities on the one hand lies in their complexity, due to the multitude of parts used, on the other hand, in the cumbersome maintenance operations. Indeed, because from the design of such installations, there is a number of blockages at grid 31 of the vacuum chamber 34. It is therefore necessary to clean frequently this grid, or even replace it with a clean grid. The design of the degassing unit leads to the accumulation of clay fragments in the bottom of the sealed vacuum chamber 34. These fragments adhere to walls and once dry, they come off and don't come to rehumidify enough to mix with the rest of clay, which causes blockage in the Faculty. The fragmentation operation is carried out from in such a way that quality cannot be guaranteed homogeneous vacuum created. Indeed, depending on the size of the fragments, we will get a variable vacuum efficiency. This efficiency is therefore random. Finally, we note, as shown in Figure 1, that the screw 30 of the mixer and the screw 33 of the extruder are two independent screws each driven in rotation by a geared motor group independent. This results in maintenance operations heavier and higher installation cost as it support pieces must be provided for each of the screws and sealing in the vacuum chamber 34.

The object of the present invention is therefore to propose a installation of a new type for manufacturing in the industrial scale of ceramics, such as bricks, tiles or the like, the number of pieces of which is reduced, whose disassembly of the shaft is facilitated and whose design is such that any accumulation of fragments of dry matter in the bottom of the unit chamber degassing is prevented.

Another object of the present invention is to provide a installation comprising means capable of supplying before dimensional material extrusion regular to increase the efficiency of degassing and guarantee its regularity so as to obtain constant quality products.

Yet another object of the invention is to provide a installation whose production stoppages are limited in due to the absence of risk of leakage at inside the vacuum chamber during the production due to the absence of parts such as seals necessary to achieve this seal.

To this end, the invention relates to an installation for manufacturing on an industrial scale of ceramics, such as bricks, tiles or the like, of the type comprising at least one screw mixer, consisting of a screw rotationally mounted inside a trough, followed by a degassing unit for the material from the mixer, this unit comprising at least one room subjected to a vacuum action and means of fragmentation of the material, this unit being followed by an extruder consisting of a screw rotatably mounted inside a trough, this extruder conveying the mixed material and degassed to a die through which the material is shaped, the chamber of the degassing unit containing a screw organized around a horizontal axis common to the screws and the mixer and the extruder, characterized in that this axis consists of a single and same solid rotating shaft carrying all the parts wear of the installation, such as blade (s), propeller (s) and fragmentation organ (s), removably mounted on said shaft, this tree being cantilevered from a geared motor for rotating said shaft up to the installation die port.

Cantilever mounting of the shaft fitted with parts removable facilitates maintenance of the installation and makes easy replacement of the shaft.

Furthermore, thanks to the design of a degassing unit or screw deaeration unit, the screw of the degassing can both be used as a fragmentation, as a scraping organ and as an organ sealing inside said chamber vacuum of the degassing unit. All of these functions can therefore be fulfilled by one and the same element, which significantly simplifies construction and design of such an installation.

According to a preferred embodiment of the invention, the shaft carrying the wear parts of the installation, rotated by means of a geared motor group, is sectioned relative to the group output tree gear motor, the junction between the two shaft sections being ensured by means of an intermediate shaft coupled to the output shaft of the reducer and receiving fitting sliding the shaft carrying the wearing parts, this same intermediate shaft being supported by at least one bearing carrier receiving the radial and axial forces of the shaft wear parts holder.

la figure 1 représente une vue de dessus d'une installation conforme à l'état de la technique ;

la figure 2 représente une vue schématique de côté en coupe de l'ensemble d'une installation ;

la figure 3 représente une vue de dessus partiellement en coupe de la liaison entre arbre de l'installation et arbre du groupe motoréducteur ;

la figure 4 représente une vue en perspective en position éclatée des éléments portés par l'arbre au niveau de la chambre de l'unité de dégazage et

la figure 5 représente une vue en coupe transversale d'une partie du malaxeur et de l'unité de désaération en position assemblée des éléments.

The invention will be clearly understood on reading the following description of an exemplary embodiment, with reference to the accompanying drawings in which:

Figure 1 shows a top view of an installation according to the state of the art;

FIG. 2 represents a schematic side view in section of the whole of an installation;

3 shows a top view partially in section of the connection between the installation shaft and the shaft of the gearmotor group;

FIG. 4 represents a perspective view in exploded position of the elements carried by the shaft at the level of the chamber of the degassing unit and

5 shows a cross-sectional view of part of the mixer and the deaeration unit in the assembled position of the elements.

The installation, object of the invention, is useful for the manufacturing on an industrial scale of ceramics, particular of bricks. By scale manufacturing industrial means an installation capable of produce a few tens of tons to a hundred tonnes per hour of extruded product. Such an installation is generally intended to be registered in a chain of more complete production including, upstream of installation, a continuous supply system material to be treated and, at least downstream of the installation a unit for cutting products to the desired size, the other dimensions being obtained by the die, and a unit for drying and possibly cooking the products. These upstream and downstream units at the installation will not be described below because they are well known to those skilled in the art art.

The installation, object of the invention, allows the realization of three operations, namely a mixing of the material, a vacuum degassing of the material and extrusion of the material through a die for its shaping. Mixer 1, integrated into the installation, is a self known. This mixer, called a screw mixer, is consisting of a solid shaft 4 carrying a helical pitch 6 to one end and blades 5 over the rest of its length. The helical pitch 6 and the blades 5 are delimited by means wear parts removably mounted on said shaft 4. Generally, these wearing parts are in the form of two half-shells intended to be assembled by appropriate connection means around the shaft 4. The assembly thus formed is rotatably mounted at inside a trough 15. This trough 15 is generally open on top to allow feeding continuously from the mixer in the material to be treated. This subject is generally carried by a conveyor belt which, at as it scrolls, brings the matter by gravity to the interior of the trough 15. The material thus brought to the inside of the trough is kneaded by the blades 5 of the mixer 1 before being brought into the portion of the mixer equipped with propellers 6. In this portion of the mixer, the walls of trough 15 of mixer 1 converge to delimit a compression mouth 25 whose role will be described below. The mixer 1 can optionally be provided with a mooring ramp and / or steam piping for allow the addition of adjuvants, such as water, to inside the material.

The shaft 4 blade carriers 5 and propeller carriers 6 of the mixer 1 is rotated by means of a geared motor group 23. This geared motor group 23 is arranged outside the mixer upstream of the latter in the direction of travel of material inside the mixer.

This mixer 1 is followed by a unit 2 for degassing the material from mixer 1. This unit 2 of degassing, which will be described in more detail below, includes a chamber 21 subjected to a vacuum action at by means of a vacuum pump 11 connected to said chamber and material fragmentation means arranged at the inlet of said room.

This degassing unit 2 is followed by an extruder 3 consisting, in a conventional manner, of a screw mounted rotation inside a trough 14. This extruder 3 conveys the mixed and degassed material to a die 22 through which the material is shaped. The trough 14 is formed, in a manner known per se, of two half-shells assembled by appropriate connecting means, these half-shells being capable of pivoting around of a substantially vertical axis to allow their swivel opening in the extruder area opposite to that carrying the die 22. Such a articulation thus facilitates access to the screw the extruder. This screw consists of a shaft 4 and wear parts 13 in the form of a propeller so as to constitute a continuous helical thread allowing the advancement of the material through the trough 14. The gauge 14 thus produced household outlet a mouth carrying the die 22 of installation. The extruder screw is also rotated by means of a geared motor group, in the occurrence in the example shown, the group geared motor 23, rotating the screw of the mixer.

The designs of mixer 1 and extruder 3 do not have in themselves no new characteristic. AT conversely, the degassing unit 2 is more particularly characteristic of the invention. Room 21 placed under vacuum from degassing unit 2 contains an organized screw around an axis common to the screws of mixer 1 and the extruder 3. This portion of the screw is in particular shown in Figure 5. This portion of the screw is consisting of a portion of the shaft 4 and wearing parts 7 which provide a helical pitch on said shaft allowing advancement of the material through said vacuum chamber 21. The vacuum pump 11, arranged outside of the installation, is connected to said chamber 21 so as to open radially into said chamber, as shown Figure 5.

Due to the aligned arrangement of mixer 1, the unit degassing 2 and extruder 3, the common axis, around of which the mixer 1, the degassing unit 2 are organized and the extruder 3, is constituted by a single shaft rotary 4. For reasons of mechanical resistance, this tree is a full tree. Due to the online design of this installation and the use of one and the same shaft 4, which constitutes both the shaft of the mixer 1, the extruder shaft 3 and the degassing unit shaft 2, it is necessary to arrange all the parts required for the operation of mixer 1, degassing unit 2 and extruder 3, so removable on this tree.

As shown in Figures 2 and 3, this tree 4, which carries all the wear parts of the installation, is cantilevered from the gear motor 23 drive in rotation from the shaft to the mouth die holder 22 of the installation. Thanks to this assembly, avoids the presence of bearings in contact with the material, which reduces maintenance operations and consequently production stop. In addition, shaft 4, which carries the wearing parts, shown in 5, 6, 9, 10 and 13, of the installation, driven in rotation by means of the group geared motor 23, is sectioned relative to the shaft of output 16 of the gearmotor group 23. The junction between the two shaft sections 4 and 16 is ensured by means of a intermediate shaft 17 coupled to the output shaft 16 of the reducer and receiving with sliding fitting the shaft 4 bearing the wearing parts. This fitting is shown in Figure 3. This same intermediate shaft 17 is supported by at least one bearing bearing the forces radial and axial of the shaft 4 wear parts holder. In the occurrence, in the example shown in Figure 3, this intermediate shaft 17 is fitted with a stop 18 constituting a bearing bearing casing the axial forces of the shaft and of the bearings 19 constituting bearings carriers receiving the radial forces of the shaft 4 workpiece carrier wear. This intermediate shaft 17 is coupled to the reducer output shaft 16 by means of a through fitting 20, such as a screw, as shown in Figure 2. This through fastener 20 comes also engaged inside a female thread central preference of the shaft 4. Thanks to such a coupling of shaft 4 to output shaft 16 of the gearmotor group 23, it becomes particularly easy to dismantle the shaft 4. Indeed, it suffices, as can be understood from in Figure 2, to remove at least part of the parts wear of the shaft, open the trough of the extruder 3, unscrew the fastener 20 and extract the shaft 4 by sliding by means of a handling device appropriate. Therefore, repair or change of a such a tree 4 becomes quick and easy.

Furthermore, this shaft 4 is mounted inclined upwards from the gearmotor group 23 to the die holder mouth 22 of the installation to center in a plane vertical the end of the tree inside the trough 14 of the extruder so as to avoid premature wear wearing parts and the bottom of the trough 14. Indeed, the made of its mounting, the shaft 4 is bent by wearing parts. This bending has the effect of making excessively rub the propellers in the bottom of the tank and therefore create premature wear not only on the propellers but also in the bottom of the tank the extruder. It is for this reason that the tree is tilted up. For example, for a tree of 5 m long with a deflection of about 15 mm, once the shaft loaded with its wearing parts, the shaft is tilted upward at the time of mounting 0.172 degrees, i.e. 10 angle minutes. Which has the effect of centering the tree in its extreme part on the side of the exit of the clay by compared to the die holder mouth.

Furthermore, the tree is mounted from the group geared motor 23 to the die holder mouth 22 of installation in such a way that the end of the tree, located inside the trough 14 of the extruder, is offset in a horizontal plane towards the side wall left or the right side wall of said trough 14, the eccentricity direction (to the right or to the left) being a function of the direction of rotation of the screw the extruder. Indeed, we noticed a lateral wear of the trough due to the pitch of the screws. Installation is not completed of clay only at its end on the outlet side, i.e. on the side of the die holder mouth 22. In this part, because the installation is full, the distribution of forces on the tree is uniform. Through against, partly upstream, the earth being partly bottom of the tanks or troughs, there is a result due to the inclination of the thread of the screw which pushes the shaft against the wall of the tank. It is for this reason that it is appropriate to offset the tree in its extreme part on the side of the die holder 22 of the installation. As example, on a 5 m long tree with a arrow of about 15 mm, the offset is 5 mm or 0.0573 degrees, i.e. 3.4 minutes of angle.

Among the wearing parts with which shaft 4 is fitted, it must be noted the presence of at least one organ of fragmentation 9. This fragmentation organ 9 consists of a grid affecting here the shape of a spoke wheel as shown Figure 4. This fragmentation member 9 carried by the shaft 4 is arranged at the inlet of the chamber 21 of the unit degassing 2. This fragmentation member 9 cooperates with the portion of helical screw contained in the deaeration 21 so as to obtain a continuous scraping of the walls of chamber 21 thereby preventing any clogging from the room. Indeed, the radial terminal portion 8 of the helical screw contained in the vacuum chamber 21 of degassing unit 2 comes flush against the plane of the fragmentation organ 9. This terminal end radial 8 of the screw has an opening 12 in the form of helical sector to allow free crossing of the fragmented material towards the extruder 3. Avoid thus any overpressure during fragmentation. This helical sector represents substantially a third of the surface of the helical step. In addition, there is provision in the hollow area 12 of the screw, a heel 24 forming a spacer between the plane of the screw thread and the plane of the 9. So, depending on the position of the rotary screw, the fragments of matter leaving the organ of fragmentation 9 can freely fall to the bottom of the vacuum chamber 21 when the exit of these fragments from the grid 9 operates when the screw is in a position of the type shown in Figure 4. The meaning of screw rotation is represented by an arrow in this figure 4. No blocking of material is observed between the rear surface of the thread and the plane of the fragmentation 9. The material having thus freely dropped and resting on the bottom wall of the vacuum chamber 21 of degassing unit 2 is then resumed on the next turn of the opinion. Thus, the screw propeller in the screw chamber 21 of the degassing unit allows, due to its design, to scrape the walls of the chamber, thus avoiding any clogging and any risk of overpressure inside said room. Once the material is taken up by the step of screw of the screw portion disposed in the chamber 21, this material is brought by means of this same screw into the area extrusion.

It is noted that the walls delimiting the vacuum chamber 21, of preferably circular, are arranged in the extension walls of the extruder trough 3.

At the entrance to chamber 21 of the degassing unit 2, the fragmentation operation can be carried out according to a large number of embodiments. In the example shown, the rotary grid 9 cooperates with a comb 10, affecting the shape of an internally castellated wheel as shown in Figure 4, this comb being arranged upstream of the grid in the direction of advancement of the material, so as to obtain a systematic shearing of the matter by regularly fragmenting it in dimensional terms. This regular fragmentation is particularly important to prevent any risk of clogging at the helical screw housed at inside the vacuum chamber 21.

It should be noted that the propeller 7 of the screw arranged at the interior of the vacuum chamber 21 could also be used as a fragmentation organ provided that the grid 9 is a static grid. The material passing to across the grid would then be systematically fragmented during the rotation of the screw portion housed at the interior of chamber 21. The organs of fragmentation 9 and 10 can be made in one piece or made in several elements, as shown in Figure 4.

The conformation of the walls of the trough 15 of the mixer 1 is such that the mixer ends with a mouth of compression 25 located immediately upstream of the fragmentation 9 or fragmentation organs 9 and 10 when the installation is equipped with at least two components of fragmentation. Conversely, room 21 of the unit of degassing 2, in combination with the screw portion 7 housed at the interior of said chamber 21 constitutes a relaxation. This is also linked to the configuration of the walls of chamber 21 and the helical pitch chosen for the screw inside the room 21. Indeed, we note that this pitch is much flatter than the pitch of the screw of the mixer. This avoids the entrainment of material towards the vacuum pump 11 which is connected the sealed chamber 21. Thus, the portion of the screw to the interior of chamber 21 performs a third function by its configuration which is to prevent training material towards the vacuum pump.

The seal between the mixing chamber delimited by trough 15 of the mixer and the delimited extrusion chamber by trough 14 of the extruder is obtained by the presence of the mass of material transported through the chamber 25. Indeed, this material is put under pressure by the propellers 6 forming the helical screw and thus form a sealing pad. So again, thanks to this design of a degassing unit 2 with screw, all sealing parts such as gasket or the like used in known installations can be deleted.

Claims (10)

1. Installation for the manufacture, on an industrial scale, of ceramics, such as bricks, tiles or the like, of the type comprising at least one screw mixer (1), made up of a screw (5, 6) rotatably mounted inside a trough (15), followed by a unit (2) for extracting gas from the material coming from the mixer (1), this gas extraction unit (2) comprising at least one chamber (21), which is subjected to a vacuum action, and means (9, 10) for fragmenting the material, this gas extraction unit (2) being followed by an extruder (3), made up of a screw (13) rotatably mounted inside a trough (14), this extruder (3) conveying the mixed and degasified material to a die (22), through which the material is moulded into shape, the chamber (21) of the gas extraction unit (2) containing a screw (7) arranged around a generally horizontal axle common to the screws (5, 6; 13) of the mixer (1) and of the extruder (3), characterised in that this axle is made up of one and the same full rotary shaft (4), which carries all of the parts of the installation subject to wear and tear, such as blade(s) (5), helix (helices) (6, 13) and fragmentation members (9, 10), mounted in a detachable manner on said shaft (4), this shaft (4) being mounted in a back-balanced manner between a reduction motor (23) for rotationally entraining said shaft and the die-carrying outlet (22) of the installation.
2. Installation according to claim 1, characterised in that the shaft (4), which carries the parts of the installation (5, 6, 9, 10, 13) subject to wear and tear, and which is rotationally entrained by means of a reduction motor group (23), is sectioned relative to the output shaft (16) of the reduction motor group (23), the union between the two shaft sections (4; 16) being ensured by means of an intermediate shaft (17), which is coupled to the output shaft (16) of the reducer and accommodates, in a sliding sleeve, the shaft (4) carrying the parts subject to wear and tear, this same intermediate shaft (17) being supported by at least one support bearing (18, 19) which encases the radial and axial forces of the shaft (4) carrying the parts subject to wear and tear.
3. Installation according to one of claims 1 and 2, characterised in that the shaft (4) is mounted upwardly inclined from the reduction motor group (23) to the die-carrying outlet (22) of the installation, to centre the end of the shaft in a vertical plane inside the trough (14) of the extruder so as to avoid premature wear and tear of the parts subject to wear and tear and of the base of the trough (14) of the extruder.
4. Installation according to one of claims 1 to 3, characterised in that the shaft (4) carrying the parts subject to wear and tear is mounted between the reduction motor group (23) and the die-carrying outlet (22) of the installation, so that the end of the shaft situated inside the trough (14) of the extruder is eccentric, in a horizontal plane, towards the left lateral wall or the right lateral wall of said trough (14), the direction of the eccentricity (towards the right or towards the left) being dependent on the direction of rotation of the screw of the extruder.
5. Installation according to one of claims 1 to 4, characterised in that the inlet of the chamber (21) of the gas extraction unit (2) comprises a fragmentation member (9), which co-operates with the helical screw portion (7, 8) contained in the air-extraction chamber (21) so as to produce a continuous scraping of the walls of said chamber (21), thereby preventing any clogging-up of the chamber.
6. Installation according to claim 5, characterised in that the terminal radial portion (8) of the screw (7), housed in the gas extraction chamber (21), lies flush against the plane of the fragmentation member (9).
7. Installation according to claim 6, characterised in that the terminal radial end (8) of the screw has an opening (12), in the form of a helical sector, to permit the fragmented material to pass freely therethrough in the direction of the extruder (3).
8. Installation according to claim 7, characterised in that a flange (24), which forms a cross-piece between the plane of the screw thread and the plane of the fragmentation member (9), is provided in the cut-away area (12) of the screw.
9. Installation according to one of claims 1 to 8, characterised in that the rotary fragmentation member (9) is a grille which co-operates with a comb (10), disposed upstream of the grille in the direction of advancement of the material, so as to produce systematic shearing of the material by fragmenting the latter in a regular manner on the dimensional plane.
10. Installation according to one of claims 1 to 9, characterised in that the mixer (1) is terminated by a compression outlet (25), situated immediately upstream of the fragmentation member or members (9, 10), while the chamber (21) of the gas extraction unit (2), in combination with the screw portion (7) housed inside said chamber (21), forms an expansion chamber to avoid material being entrained in the direction of a vacuum pump (11), to which said air-tight chamber (21) is connected.

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