Pratigliolmi Cotto Nobile di Toscana, a leading company for the production of high quality bricks, has installed a new Easymud system supplied and succesfully commissioned by Capaccioli in 2004.
The Easymud line produces floor/ceiling tiles, rustic bricks and various specials.
Indeed, what makes this system so special is that its products look as though they were made by hand, and the moulds need no sanding. Capaccioli supplied all the equipment needed for preparing materials, shaping, handling and setting.
Drying and firing is done in the pre-existing dryers and kilns.
The milled clay is fed from a box feeder to a double shaft mixer on a conveyor belt.
Water is added to the clay in the mixer until the body has a moisture content of around 30%.
As the production body leaves the mixer, it is pressed through a filter and drops onto another conveyor that takes it to a vertical blending mixer that sends the body on to the next system in operation: either a floor –tile press, a brick moulder or a special product press.
Three each floor tile moulds, measuring 150 mm x 300 mm are arranged on a given mould carrier. The washed and dried moulds are sprayed with oil and then powdered with sawdust to give the fired tile a rustic appearance.
The oil holds the sawdust in place, and any excess sawdust is vacuumed off. The thusly prepared moulds are the moved in under the dispenser.
This newly engineered filling system from Capaccioli, named “APE”, fills body into the three moulds at once and combines three steps: mixing, compressing and clay distributing into the mould. Special devices inside the “APE” randomly combine the three phases. Such randomness is generated by a computer that makes the procedure always different and never repetitive in order to obtain items different one from the other. Each product is unique – unlike those made in older press systems, where certain surface finish effects are constantly repeated.
One of the plant’s most important feature is that Capaccioli has managed – before any one else – to make products with the same, low body density as that of hand made products.
By contrast, products made by older systems have higher body densities. Furthermore the APE can be programmed to give the desired, preset body density.
The lower density reportedly generally keeps low body stress levels, so the products are not only more frostproof, but also easier to dry and fire.
While the tiles are still in the moulds, their backs are sanded a little in preparation for drying.
A metal drying frame is placed on each of the three – mould carriers and then turned over together with the moulds, and the live bottoms of the moulds move up to eject the tiles.
The drying frame circulation system serves the three shaping lines (floor tiles, bricks and specials).
As the moulds circulate, they are washed, dried, sprayed with oil and sawdust again, and refilled.
The wash water is cleaned in two settling tanks and then reused.
Drying and setting
The drying frames are placed on dryer cars, before the cars are taken to the dryer. The floor tiles are dried in the chamber dryer; after a drying time of three days, an automatic setting facility arranges the items on tunnel kiln cars. The floor tiles are set according to a special pattern with gaps in between to keep the products from splotching during the firing process. The kiln cars have a setting height of 1.50 m.
Firing, unloading and packaging
The products are fired in a pair of tunnel kilns, firing takes place at one of two temperatures, depending on the type of clay: bricks and roof tiles are fired at 950°C; floor tiles and specials at 980°C. Since each load fired always constitutes a mix of different products, the firing time is fixed at 50 hours for all.
After firing, the products are distributed over several different lines for mechanical unloading; only special products are unloaded by hand.
Floor tiles are unloaded directly from the kiln cars as packets and packaged as – set; it is otherwise possible to sort the pieces; the tiles will be bound together in groups of eleven, and 36 such packets packaged together.
The pallets are stored in water for a certain length of time after firing.
|Easymud APE||2.200 pieces/hours||Roof tiles 15×30|
|Easymud BRICK||2.500 pieces/hours||Brick UNI|
|Easymud S 32||7 prints/minute||one or more special pieces/mould|