Hague International

Gerald G Gallant, Jr

John W Bjerklie

Paul G LaHaye

An energy conserving process furnace has a recuperator to utilize heat derived from exhaust gases in order to reduce fossil fuel consumption of the furnace. Elongated, enhanced surface ceramic heat exchanger tubes are used in the recuperator to recover heat energy from the exhaust gas. A preferred sealing arrangement is used between the metal and ceramic tubes to contain the combustion air. Heat is added by the recuperator to combustion air used in a fluid fuel burner. The ceramic tubes are provided with vibration protective mechanisms to prolong useful life under severe mechanical vibration encountered in some applications. In a method of operating a slot furnace, exhaust gas is exhausted from a side of the furnace through the slot or a passageway having an elongated horizontal cross section. In the preferred arrangement a second passage or air curtain passageway is positioned adjacent the first passageway to permit proper gas flow through a recuperator. The recuperator is designed to recoup heat from exhaust gas in the first passageway and provide such heat as energy to heat combustion air used in the furnace. The second passageway by-passes the recuperator to avoid passing colder room air through the recuperator and to protect the operator from high temperature exhaust gas. The heat exchange ceramic tubes are designed to operate at temperatures of 1300.degree. F. and above without damage and with good sealing properties between elements. The system preferably includes a recirculating burner means which acts to reduce the combustion air requirements and to provide a combustion zone low in oxygen so as to prevent scale formation and oxidation of metals being treated in the furnace area.

Energy conserving process furnace system and components thereof

An energy conserving process furnace has a recuperator to utilize heat derived from exhaust gases in order to reduce fossil fuel consumption of the furnace. Elongated, enhanced surface ceramic heat exchanger tubes are used in the recuperator to recover heat energy from the exhaust gas. A preferred sealing arrangement is used between the metal and ceramic tubes to contain the combustion air. Heat is added by the recuperator to combustion air used in a fluid fuel burner. A recirculating burner has a flame front outside of the burner in the combustion chamber. The recirculating burner means acts to reduce the combustion air requirements and to provide a combustion zone low in oxygen so as to prevent scale formation and oxidation of metals being treated in the furnace area.

An energy conserving process furnace has a recuperator to utilize heat derived from exhaust gases in order to reduce fossil fuel consumption of the furnace. Elongated, enhanced surface ceramic heat exchanger tubes are used in the recuperator to recover heat energy from the exhaust gas. A preferred sealing arrangement is used between the metal and ceramic tubes to contain the combustion air. Heat is added by the recuperator to combustion air used in a fluid fuel burner. The ceramic tubes are provided with vibration protective mechanisms to prolong useful life under severe mechanical vibration encountered in some applications. In a method of operating a slot furnace, exhaust gas is exhausted from a side of the furnace through the slot or a passageway having an elongated horizontal cross section. In the preferred arrangement a second passage or air curtain passageway is positioned adjacent the first passageway to permit proper gas flow through a recuperator. The recuperator is designed to recoup heat from exhaust gas in the first passageway and provide such heat as energy to heat combustion air used in the furnace. The second passageway by-passes the recuperator to avoid passing colder room air through the recuperator and to protect the operator from high temperature exhaust gas. The heat exchange ceramic tubes are designed to operate at temperatures of 1300.degree. F and above without damage and with good sealing properties between elements. The system preferably includes a recirculating burner means which acts to reduce the combustion air requirements and to provide a combustion zone low in oxygen so as to prevent scale formation and oxidation of metals being treated in the furnace area.

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Gorham, ME, United States of America

Gerald G Gallant, Jr