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Granite and quartzite stone slabs processing by oxy-methane flaming

Objective



The proposed research project addresses the solution of a problem encountered in the industry of granite and quartzite slabs production; nowadays there is a strong market request of specially finished stones slabs (for functional, economic and aesthetics purposes) that are worked to obtain particular superficial roughness.

The industrial systems for granite and quartzite slabs flaming, in the last decades, did not experience the same technologic improvements that followed instead by the equipment for stone cutting and working.
To meet the market needs, a large number of machines for slabs flaming is needed, this implies high cost of investment and personnel, high cost of fuel and high rates of rejected slabs.

The finishing of stones is performed by means of flaming their surface with high temperature jet flame to sputter the stone's splinters. The fuels and comburent used at the present are very expensive (compressed tetrane and propane, that are burnt with oxygen). The nowadays used torches are conceived for metal cutting and assembled on modified bushammering machines; the adoption of such empirical solutions reflects a poor quality of the surfaces and high rates of slabs rejected because breakage.

An industrial research project is underway to develop improved systems, based on properly developed innovative blowpipes and nozzles, for the superficial working of stone slabs with a jet flame obtained from the combustion of the cost effective natural gas methane and oxygen generated on the site with the process of pressure swinging adsorption of the air.

The major achievements expected from the project are :

The reduction of the costs of slabs processing. The aforementioned fuels can be replaced by the much more economic gas methane whose availability is guaranteed to the end users (the stone producers), by the pipeline EU network that is the most spread in the world and a more cost effective comburent. The transport of pressurised tanks of flammable gases and their storage in proper safety rooms, inside the working area, will be no more necessary and this will contribute to safety at work and to a further decrease of production costs.
The development of improved systems for slabs working. This will reflect an improved quality of superficial finishing, will allow the increase of the rate of production and will reduce the rate of rejected slabs due to breakage.

The above objectives will be pursued by the development of innovative torches and advanced improved systems for slabs movimentation. These systems will be equipped with proper control systems to vary the operating parameters of the process as function of stones' kind and thickness.

The development of the new torches capable of obtaining suitable temperatures is performed by the detailed thermal fluid dynamic characterisation of the jet flame, included combustion kinetics, with advanced computer tools. The results of the parametric analyses will allow the optimisation of the most important operative variables controlling the flaming process: the exact regulation of oxy methane mixture and the outlet pressure range.

The developed high performance flaming devices will be integrated into an improved system for slabs movimentation to obtain the minimisation of step motion, vibrations and a sufficient flexibility of the process parameters. A prototype will be developed and its performance will be experimentally tested on real scale.

The consortium that will carry out the project groups five
complementary partners of three EU Countries and is driven by a medium industrial enterprise involved, since 33 years, in systems for marbles and granites processing.

Coordinator

Campagnola & Fedeli Meccanica
Address
Via Dell'artigianato 10
37024 Verona
Italy

Participants (4)

Kogler Natursteinbruch & Schottenwerk
Austria
Address
5,St. Urban, Stattenberg 5
9560 Feldkirchen
NATIONAL TECHNICAL UNIVERSITY OF ATHENS*ETHNICON METSOVION POLYTECHNION
Greece
Address
9,Heroon Polytechniou 9
15780 Athens
Rgi Resource Group Integrator Srl
Italy
Address
Via Al Molo Vecchio
16126 Genova
Wurmitzer Entwicklung & Vertrieb GmbH
Austria
Address
5,Pojedl
9562 Himmelberg