M. S. E. Stanescu, The Linde Group, Durham, NC; P. F. Stratton, The Linde Group, Huddersfield, West Yorkshire, United Kingdom; L. N. Druga, UTTIS Industries, Bucharest, Romania
Flexible curtains allow products of various sizes and shapes to enter and leave continuous furnaces and their zones, while maintaining a barrier against interior atmosphere escape and exterior atmosphere intrusion. This paper provides information about some curtain materials, some designs of curtains and curtain boxes used in continuous furnaces for heat treating including annealing, brazing and P/M sintering and contains a particular example of curtains use in a brazing continuous roller hearth furnace. Also, this paper mentions factors to take into account in selecting curtains, their main advantages and limitations and some curtain system designs in development and patent pending. More than ever, using curtains for reducing the cost of heating energy (by 15%-20%) and consumption of gases for protective or reactive atmospheres used in continuous furnaces (by 10%-20% or more), becomes a matter of first priority.
Summary: Flexible curtains allow products of various sizes and shapes to enter and leave continuous furnaces or zones (ex: hot zone and cooling zone) of the continuous furnaces while maintaining a barrier against interior atmosphere escape and exterior atmosphere intrusion. Curtains could be installed in batch and continuous furnaces used for many heating processes not limited to heat treating such as heating for forging, slab reheating, etc. This paper provides information about some curtain materials, some designs of curtains and curtain systems used in continuous furnaces for heat treating including annealing, brazing and P/M sintering and contains a particular example of curtains use in a brazing continuous roller hearth furnace. Also, this paper mentions factors to take into account in selecting curtains, their main advantages and limitations and some curtain system designs in development and patent pending. More than ever, reducing the cost of heating energy and consumption of gases for protective or reactive atmospheres used in continuous furnaces, in heat treating including annealing, P/M sintering, brazing, becomes a matter of first priority. Curtains in a continuous roller hearth furnace used in annealing may reduce electrical energy or natural gas usage for heating by 15%-20% and gases for the atmosphere by 10%-20% or more.
