Plant and method for regenerating sand from foundry cores and moulds by calcination in a fluidized-bed furnace
AssigneeFata Industriale S.p.A.
InventorMarino Selli
Life of this patent
Estimating the term…
Abstract
The invention relates to plant (1) and to a method for regenerating sand from foundry cores and moulds by calcination in a fluidized-bed furnace (2), the main characteristic of which lies in the fact that the fumes leaving the calcining furnace are used to heat a current of air which is then used, in its turn, to heat the sand to be treated at its inlet to the calcining furnace, and in that the current of air cooled by the sand to be treated is then heated by means of the purified sand leaving the calcining furnace and is then used as combustion air in the calcining furnace.
Claims5
Plant for regenerating sand from foundry cores and moulds, including a fluidized bed calcining furnace having means for feeding a gaseous fuel and means for feeding air into a calcination bed formed by said sand so as to burn said fuel within, fluidize and calcine said sand bed to regenerate said sand, and respective means for withdrawing regenerated sand and combustion fumes from said calcining furnace;
- and wherein said plant further includes:
- air delivery means;
- first heat exchange means connected to said air delivery means and said means for withdrawing fumes from said furnace for heating air delivered by said air delivery means by means of said fumes withdrawn from said calcining furnace;
- second heat-exchange means connected to said first heat exchange means for preheating the sand to be regenerated by means of the heated air leaving the first heat exchange means;
- air circulating means connected to said second heat exchange means for circulating air leaving said second heat-exchange means;
- third heat-exchange means connected to said air circulating means and said means for withdrawing regenerated sand from said furnace for heating air circulated thereto by said circulating means by means of the regenerated sand delivered from said calcining furnace by the respective said withdrawing means;
- and
- said means for feeding air to said calcination bed being supplied with air heated in said third heat-exchange means whereby any noxious substances with which this air may have been enriched in passing through said second heat-exchange means are substantially eliminated.
A method for regenerating sand from foundry cores and moulds in a fluidized bed calcining furnace having means for feeding a gaseous fuel and means for feeding air into a calcination bed formed by said sand so as to burn said fuel within, fluidize and calcine said sand bed to regenerate said sand and respective means for withdrawing regenerated sand and combustion fumes from said calcining furnace comprising:
- heating a current of air in a first heat exchanger by means of fumes leaving said furnace;
- preheating the sand to be regenerated in a second heat exchanger by means of the heated current of air;
- circulating the current of air leaving said second heat exchanger to a third heat exchanger to reheat said current of air by means of regenerated sand delivered from said currents to said third heat exchanger and feeding said reheated current of air to said calcination bed.
Dependencies are inferred from the claim text.