Apparatus and method for vacuum vibro-compression of mixes

A method for production of slabs by means of vacuum vibro-compression of mixes arranged on a support using an apparatus comprising:

• a press provided with a press ram having vibratory devices and a pressing surface on which the support is positionable, the press comprising a vacuum bell provided with an inlet opening and an outlet opening;
• 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 is 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, respectively;
• 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 opening and 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, respectively, 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, the method comprising steps of:
• a) inserting the support with a mix thereon inside the entry chamber and closing the first gate;
• b) generating a predetermined vacuum value inside the entry chamber with the first gate and the second gate closed;
• c) opening the second gate and transferring and inserting the support with the mix thereon inside the vacuum bell, whereby a predetermined vacuum value is present in the vacuum bell prior to and during each of said opening of the second gate and said transferring and inserting;
• d) closing the second gate and performing vacuum vibro-compression of the mix with the second gate and the third gate closed, the vacuum vibro-compression being performed to completion so as to compact the mix into a slab;
• e) once the vibro-compression has been completed and the mix is compacted into the slab, opening the third gate and transferring the support with the mix thereon now in a form of a slab into the exit chamber, whereby a predetermined vacuum value is present in the exit chamber prior to and during each of said opening of the third gate and said transferring;
• f) closing the third gate and exposing the slab to atmospheric pressure inside the exit chamber;
• and
• g) opening the fourth gate and discharging the support from the exit chamber wherein the mix comprises stone or stone-like material and a bonding resin.