After starting production in 2004 with a yearly output of 21 million plain and extruded interlocking roofing tiles, the Creaton Company decided to extend the Lenti plant in Hungary for the production of pressed interlocking roofing tiles.
Because the raw material is of good quality, it was possible to manage without the two-stage rolling process in the preparation for the production of plain tiles. For pre-crushing, a screening and mixing crusher type SBM 1900 was installed. Further crushing during phase I was achieved with a single stage roller mill type Titan – M (1 000 x 1 000 mm).
For the manufacture of pressed interlocking roofing tiles the plant was extended by installing a second fine roller mill type Titan 1 000 x 1 000 mm – M (mechanical design) with an effective roller gap of 0.8 mm. The throughput capacity of this plant amounts to 59 t/h.
During the erection of plant I a round storage system with a diameter of 30 m and a storage capacity of 5 100 m³ was already provided for as a clay storage (aging house), which was sufficient for both plants. The discharge capacity of the store amounts to 28 m³/h. According to the demand, the material is separated via a belt shunt into the two plants I and II.
In the new plant II, the material is transported directly to the specials plant and for the flat tile plant a box feeder with rubber belt has been installed as a material buffer.
Flat tile plant
In the flat tile plant, which is designed for an output of 2 905 tiles per hour, a circular screen feeder type SR 1900 – S was installed. This machinery has to perform several tasks at the same time: Firstly a further addition of water takes place at the machine; then waste from the extruder and the slug excess are incorporated into the fresh material; and the machine acts as a material buffer before the extruder.
A Variat type extrusion unit is installed, which is a combination of a de-airing double shaft mixer type VDWM 2308 and an auger extruder type SP 560/500. The slugs at the extruder die are extruded as a double extrusion, one above the other, and are subsequently cut by a wire cutter with automatic slug length adjustment. In order to avoid the extruder switching off of in case of a press stop, a shunt for slug overrun was installed in the feed system. After adjusting the clay bats in both longitudinal and transverse direction, the inlet into the roofing tile press is synchronized between the clay bat feed and the press.
A revolving roofing tile press type DR-6/2400 – H is installed, fitted with 4 upper and 24 lower moulds. This press, which is one of the largest of its type in the world, has the following technical data:
› Length of loading drum surface: 2 400 mm
› Depth of drum surface: 640 mm
› Press capacity: 400 t
› Take-up of lateral push: 100 t
› Number of eccentric bearings: 4
› Weight: 54 000 kg
Technically the press is in accordance with the state of the art because of the use of hydraulic upper mould tensioning as well as an upper mould adjusting device to compensate for gypsum abrasion. The product take-off device is hydraulically driven, ensuring a highly precise set-down of products onto the supporting frame. The possibility of the tile dropping from the suction head and suffering deformation has been eliminated. Additionally the tiles are moved hydraulically from the mould spacing on the press to the tile spacing on the supporting frame.
The drum length of 2 400 mm ensures that no waste is wedged between the moulds with the production of large format tiles.
The specials plant starts with a circular screen feeder type SR 1900 – S which also acts as a material buffer.
A Variat type extrusion unit is installed, which is a combination of a de-airing double shaft mixer type VDWM 2007 and an auger extruder type SP 450/400.
The automatic adjustment of the cutting length is required in particular for specials plants. The clay bats are fed via the feed system of the roofing tile specials press to the turntable press type DTP-3. This roofing tile specials press, which has three lower and one upper mould, is freely programmable in all axes. Because of this high flexibility any possible pressing curve can be run. More-over, de-moulding can be set to the minimum speed necessary for maximum production output. Gentle and precise set-down of the tiles onto the drying frames is naturally done by the axis control.
The machinery has the following technical data:
› Working stroke, variable: up to 340 mm
› Mould pack height: up to 300 mm
› Pressing force: 160 t
› Weight: 10 000 kg
The complete plants are monitored by a Siemens S7 control system. The individual control systems are connected via process data highway.
In cooperation with the Creaton Company the technicians and engineers of Rieter Werke have developed and realized a project of the highest technical standard.