APPARATUS AND METHOD FOR VACUUM VIBRO-COMPRESSION OF MIXES

Abstract

An apparatus for vacuum vibro-compression of mixes arranged on a support comprises a press (12) provided with a press ram (18) having vibratory devices (22), and a pressing surface (16). The press (12) comprises a vacuum bell (24). The apparatus is characterized in that it comprises an entry chamber (44) in the region of the inlet opening (36) of the bell (24) having a first opening (48) which can be controllably closed and opened with a first gate (50) adapted to prevent fluid communication between the outside and inside of the entry chamber (44) and a second gate (52) able to be controllably opened and closed, in the region of the inlet opening (36) of the bell (24), and adapted to prevent fluid communication between entry chamber (36) and the inside of the bell (24) or to allow the passage of the support with the mix from the entry chamber (36) to the inside of the bell (24). The apparatus also comprises an exit chamber (46) in the region of the outlet opening (38), having a third gate (54) provided in the region of the outlet opening (38), able to be controllably closed and opened and adapted to prevent fluid communication between the inside of the bell (24) and the inside of the exit chamber (46) or to allow the passage of the support with the compacted slab from inside the bell (24) to the exit chamber (46), and a second opening (56) which can be controllably closed and opened with a fourth gate (58) which is adapted to prevent fluid communication between the inside of the exit chamber and the outside. A method for vacuum vibro-compression of mixes contained inside a mould, comprising the steps of: inserting a support with the mix inside the entry chamber (44) and closing the first gate (50); generating a given vacuum value inside the entry chamber (44) with the first gate (50) and the second gate (52) closed; opening the second gate (52) and inserting the support inside the bell (24) where a given vacuum value is already present; closing the second gate (52) and performing vacuum vibro-compression of the mix with the second and third gates (52, 54) closed; once vibro-compression has been completed, opening the third gate (52) and transferring the support into the exit chamber (46) where a given vacuum value is already present; closing the third gate (54), restoring the atmospheric pressure inside the exit chamber (46); opening the fourth gate (58) and discharging the support.

Claims

1. An apparatus for production of slabs by means of vacuum vibro-compression of mixes arranged on a support, comprising a press provided with a press ram having vibratory devices and a pressing surface on which a support is positionable, the press comprising a vacuum bell provided with an inlet opening and an outlet opening; and a first means for generating a vacuum inside the vacuum bell; an entry chamber in a region of the inlet opening of the vacuum bell and having a first opening that is controllably closable and openable with a first gate so as to prevent fluid communication to and from the entry chamber, the entry chamber comprising a second gate that is controllably closable and openable, in the region of the inlet opening of the vacuum bell and adapted to prevent fluid communication between, and allow passage of the support from and to, the entry chamber and an inside of the vacuum bell; and an exit chamber in a region of the outlet opening of the vacuum bell and having a third gate provided in the region of the outlet openingand controllably closable and openable and adapted to prevent fluid communication between, and allow passage of the support from and to, the inside of the vacuum bell and the exit chamber, the exit chamber having a second opening that is controllably closable and openable with a fourth gate so as to prevent fluid communication to and from the exit chamber; said entry chamber and said exit chamber being connected to a second vacuum generating means.

2. The apparatus according to claim 1, characterized in that said gates each comprise an element that is slidable vertically inside a box-shaped element provided with a window for passage of the support, and which is openable and closable by means of the slidable element.

3. The apparatus according to claim 2 the preceding claim, characterized in that an edge of the window is provided with an inflatable seal adapted to prevent fluid communication.

4. The apparatus according to claim 1, characterized in that said second gate and said third gate comprise a perimetral seal adapted to prevent fluid communication between an edge of either of the entry chamber or the exit chamber and the vacuum bell.

5. The apparatus according to claim 1, characterized in that said second gate and said third gate are formed by a side surface of the vacuum bell.

6. The apparatus according to claim 5, characterized in that the vacuum bell is movable between a first lowered position so as to allow formation of the vacuum and a second raised position so as to allow manual cleaning and maintenance operations to be performed.

7. The apparatus according to claim 1, further comprising movement means for the support inside the apparatus, the movement means provided with lateral grippers adapted to grip side flaps provided on the support and to move the support along a surface of the apparatus which acts as a support element.

8. The apparatus according to claim 7, characterized in that the movement means comprise: a first movement means for displacement of the support into the entry chamber and then into the vacuum bell; and a second movement means for displacement of the support from the vacuum bell into to the exit chamber and then out of the exit chamber.

9. The apparatus according to claim 7, characterized in that the first movement means and the second movement means each comprise a carriage provided with wheels adapted to travel on rails.

10. The apparatus according to claim 1, characterized in that said first vacuum generating means and said second vacuum generating means comprise at least one vacuum pump and shut-off valves for selectively interrupting air flow.

11. A method for production of slabs by means of vacuum vibro-compression of slabs arranged on a support, using the apparatus according to claim 1, comprising the steps: a) inserting a support with a mix inside the entry chamber and closing the first gate; b) generating a given vacuum value inside the entry chamber with the first gate and the second gate closed; c) opening the second gate and inserting the support with the mix inside the vacuum bell where a predetermined vacuum value is already present; d) closing the second gate and performing vacuum vibro-compression of the mix with the second gate and the third gate closed; e) once the vibro-compression has been completed, opening the third gate and transferring the support with the mix now in a form of a compacted slab into the exit chamber where a predetermined vacuum value is already present; f) closing the third gate, restoring atmospheric pressure inside the exit chamber; and g) opening the fourth gate and discharging the support.

12. The method according to claim 11, wherein, at same time as opening of the second gate in order to transfer the support from the entry chamber to the vacuum bell, the third gate is opened in order to transfer the support from the vacuum bell to the exit chamber.

13. The method according to claim 11, characterized in that, during vacuum vibro-compression, the first gate is opened for entry of the support into the entry chamber and the fourth gate is opened for exit of the support from the exit chamber.

14. The method according to claim 13, characterized in that during vibro-compression deaeration of the mix present in the entry chamber occurs.

Description

[0047] The characteristic features and the advantages of the present invention will emerge more clearly with reference to a number of examples of application, provided by way of non-limiting illustration, with reference the attached drawings in which:

[0048] FIG. 1 shows a cross-sectional view, in schematic form, of a press in two different operating conditions, with the ram raised on the left-hand side and with the ram lowered and slab compacted on right-hand side;

[0049] FIG. 2 is similar to FIG. 1, in which, however, in addition to the ram, also the bell is raised;

[0050] FIGS. 3 and 4 show two longitudinally sectioned views of an apparatus according to the present invention during two different operating steps; and

[0051] FIGS. 5-8 show in schematic form a number of larger-scale views of some of the components of the apparatus according to the present invention.

[0052] In the attached figures, the reference number 12 denotes an apparatus according to the present invention for vacuum vibro-compression of mixes arranged on a support.

[0053] As mentioned above, FIG. 1 shows a cross-section through a press 14 for vacuum vibro-compression.

[0054] The press 14 comprises a pressing surface 16 and a press ram 18 which may be moved towards or away from the pressing surface 16 by means of movement means 20.

[0055] The movement means 20 may comprise, for example, four oil-hydraulic cylinders which are connected to the press ram 18 in the vicinity of its outer edge.

[0056] The type and operating principle of the movement means 20 will not be further described because it is known per se to the person skilled in the art and since they do not constitute a specific subject of the present invention.

[0057] The press ram 18 is provided with vibratory devices 22 which can be controllably operated so as cause vibration of the ram 18.

[0058] The vibratory devices 22, since they are known per se to the person skilled in the art, will also not be further described.

[0059] The press 14 comprises a vacuum bell 24, referred to hereinbelow also as bell 24. The bell 24, according to a possible embodiment, may comprises a side wall 26 and an upper peripheral rim 28 partially covering the zone inside which the vacuum is created. The remaining upper covering may be obtained by means of the ram 18 which makes contact with the peripheral rim 28 via a sealing element 30.

[0060] As can be noted from the longitudinal section shown in FIG. 3, an inlet opening 36 and an outlet opening 38 are provided on the transverse parts 32, 34 of the side wall 26.

[0061] During operating conditions, the side wall 26 of the bell 24 rests on the pressing surface 16. Advantageously a seal 40 may be arranged between side surface 26 and pressing surface 16 in order to prevent fluid communication between inside and outside of the bell along the perimeter.

[0062] When the bell 24 rests on the pressing surface 16, the inside of the bell 24 is however accessible via the inlet opening 36 and the outlet opening 38.

[0063] In accordance with a possible embodiment of the present invention, the bell 24 may be raised with respect to the pressing surface 16 by means of the press ram 18, as can be seen in FIG. 2. For this purpose, the press ram 18 may comprise a projecting peripheral rim 42 adapted to engage, beyond a certain raising height of the press ram 18, with the upper peripheral rim 28 of the bell 24. The height at which engagement occurs is greater than the height to which the press ram 18 is raised in order to insert a support. The bell may then be displaced upwards so as to create an access way for the operator in order to carry out maintenance or cleaning operations.

[0064] In accordance with a possible embodiment of the present invention, a further seal may be arranged between press ram 18 and bell 24, in particular between the projecting peripheral rim 42 and the bell 24. Advantageously, a chamber may therefore be created between the bell and the press ram and this chamber may be placed under pressure (for example with a regulatable pneumatic pressure) in order to adjust the pressing force of the ram on the mix during vibration.

[0065] An entry chamber 44 is provided in the region of the inlet opening 36 and an exit chamber 46 is provided in the vicinity of the outlet opening.

[0066] The entry chamber 44 is provided with a first opening 48 for entry of the support together with the mix, which can be controllably closed and opened with a first gate 50. The first gate 50 is adapted to prevent fluid communication between outside and inside of the entry chamber 44.

[0067] The entry chamber 44 is also provided with a second gate 52 which can be controllably closed and opened. The second gate 52 is adapted to prevent fluid communication between entry chamber and inside of the bell 24 or to allow the passage of the support with the mix from the entry chamber to the inside of the bell. The second gate 52 is provided in the vicinity of the inlet opening 36.

[0068] The exit chamber 46 is provided with a third gate 54 which can be controllably closed and opened. The third gate 54 is adapted to prevent fluid communication between the inside of the bell 24 and exit chamber 46 or to allow the passage of the support with the compacted slab from inside the bell 24 to the exit chamber 46. The third gate 54 is arranged in the region of the exit opening 38.

[0069] The exit chamber 46 is also provided with an opening 56 which can be controllably closed and opened with a fourth gate 58. The fourth gate 58 is adapted to prevent fluid communication between the inside of the exit chamber 46 and the outside and allows exit of the support with the compacted slab.

[0070] The entry chamber 44 and the exit chamber 46 may be provided with associated vacuum pumps (not shown). In accordance with a possible alternative embodiment a single vacuum generation plant may be provided so as to serve both the bell 24 and the entry chamber 44 and exit chamber 46, said plant being provided with shut-off valves known per se.

[0071] In accordance with a possible embodiment of the present invention, the gates 50, 52, 54, 58 are slidable vertically between an open position and a closed position. Other embodiments of the gates where they may be hinged at the top or in some other way may be envisaged.

[0072] FIGS. 5 and 6 show a possible configuration of a fourth gate 58 in the open position and closed position, respectively. The gate may comprise an element 60 vertically sliding inside a box-shaped element 62 provided with a window 64 for passage of the mould, which can be opened and closed by means of the sliding element 60. The first gate 50 may have a constructional design entirely similar to that of the fourth gate 58.

[0073] The edge of the window 64 may be provided with a perimetral seal 66 directed towards the sliding element 60 so as to prevent fluid communication between the sliding element 60 and the box-shaped element 62. Advantageously the seal 66 may be of the inflatable type, as shown in FIGS. 5 and 6, which show the gate in the open condition and closed condition, respectively.

[0074] The seal 66 may be a single seal and therefore have a form corresponding to the form of the window, or may consist of separate elements.

[0075] The movement of the sliding element 60 of the gate may be obtained by means of an actuator 68 known per se to the person skilled in the art.

[0076] Closing of the gate may therefore be performed by means of the lowering of the sliding element towards the bottom of the box-shaped element and by means of subsequent inflation of the seal.

[0077] A possible embodiment of the third gate 54 is shown in FIGS. 7 and 8 in which the same parts as for the first and fourth gates are reproduced. A second perimetral seal 70, entirely similar to the seal 66, may also be provided for ensuring the sealing action between an edge of the exit chamber 46 and bell 24. In particular, the seal acts between the side surface of the bell 24 around the outlet opening 46 and the surface of the exit chamber 46 around the corresponding window. The second gate 52 may have a constructional design entirely similar to that of the third gate 54.

[0078] Alternative embodiments are also possible where the external structure of the bell forms a single body with the respective entry and exit chambers and therefore there is no need for a seal between these two elements.

[0079] Movement means 72, 74 are used for movement of the support inside the apparatus according to the present invention.

[0080] In accordance with a possible embodiment of the present invention, the movement mean 73, 74 comprise: [0081] first movement means 72 for displacement of the support 13 from outside to the entry chamber 44 and then to the inside of the bell 24; and [0082] second movement means 74 for displacement of the support 13 from inside the bell 24 to the exit chamber 24 and then outside.

[0083] The first and second movement means 72, 74 may each comprise a carriage provided with wheels 76 adapted to travel on rails 78.

[0084] The carriage may comprise, on each side, lateral grippers 80 adapted to grip a flap 82 provided on each side surface of the support. Advantageously, the flaps 82 project in a direction perpendicular to the direction of advancing movement of the support 13 inside the apparatus. According to this embodiment of the invention, the lateral grippers 80 are therefore adapted to grip the projecting flaps in a direction perpendicular to the direction of advancing movement of the supports.

[0085] In order to perform displacement, once the flaps have been gripped, the carriage moves the supports together with their contents, without raising them, causing them to slide over the bottom of the apparatus which acts as a support element, the supports and their contents not having any inherent rigidity.

[0086] The operating principle of the apparatus according to the present invention will now be described in detail, with reference to only the vibro-compression step, since the other steps in the process may be conducted in a manner known to the person skilled in the art and in any case they do not constitute a specific subject of the present invention.

[0087] The method for the vacuum vibro-compression of mixes contained within a support, using an apparatus 12 according to the present invention, comprises the steps of: [0088] a) inserting a support with the mix inside the entry chamber 44 and closing the first gate 50; [0089] b) generating a given vacuum value inside the entry chamber 44 with the first and second gates 50, 52 closed; [0090] c) opening the second gate 52 and inserting the support together with mix inside the bell 24 where a predetermined vacuum value is already present; [0091] d) closing the second gate 52 and performing vacuum vibro-compression of the mix with the second and third gates 52, 54 closed; [0092] e) once the vibro-compression has been completed, opening the third gate 54 and transferring the support with the compacted slab into the exit chamber 46 where a predetermined vacuum value is already present; [0093] f) closing the third gate 54, restoring the atmospheric pressure inside the exit chamber 46; and [0094] g) opening the fourth gate 58 and discharging the support with the slab.

[0095] Preferably, in order to carry out a continuous cycle for production of the slabs, it is possible, during the step where vibro-compression is performed with the second and third gates 52, 54 closed, to open the first gate 50 for positioning of a support with the mix to be compacted inside the entry chamber 44.

[0096] At the same time, it may be envisaged opening the fourth gate 58 in order to unload the support containing the compacted mix inside the exit chamber 46.

[0097] As also mentioned above, in the apparatus according to the present invention it is possible to maintain continuously the vacuum condition inside the bell 24.

[0098] In this way it is therefore possible to avoid time being wasted in order to cyclically expose the bell to vacuum conditions and atmospheric pressure. It is worth noting that, owing to the small volume of the entry and exit chambers upstream and downstream of the vibro-compression bell, it is also possible to reduce the amount of energy which is used.

[0099] It is also worth noting that a further advantage is that the entry chamber 44 is already under vacuum conditions so that the mix is inserted inside the bell 24 already deaerated. The press ram may then be immediately lowered and vibro-compression of the mix performed.

[0100] The person skilled in the art, in order to satisfy specific requirements, may make modifications to the embodiments described above and/or replace the parts described with equivalent parts, without thereby departing from the scope of the accompanying claims.