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US 9,650,304 B2Granted
Tunnel kiln for firing ceramic porous bodies
AssigneeNGK Insulators, Ltd.
InventorsJotaro Miyata, Chikashi Ihara, Takashi Yasue
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AssigneeNGK Insulators, Ltd.
InventorsJotaro Miyata, Chikashi Ihara, Takashi Yasue
Estimating the term…
The invention provides a tunnel kiln for firing ceramic porous bodies which can fire ceramic porous bodies containing organic binders in a shorter period of time than in conventional methods without producing breaks or requiring nitrogen gas. The tunnel kiln includes a preheating zone 1, a firing zone 2, and a cooling zone 3 and fires the ceramic porous bodies loaded on a carriage 7 by driving it in a furnace. A heat storage regenerative burner 10 is used as means of heating the firing zone 2 so that low-oxygen-concentration exhaust gas discharged from the heat storage regenerative burner 10 may be returned to an exhaust gas return line 14 and supplied into the preheating zone 1. The exhaust gas return line 14 may be provided with a combustion device 17 that reduces the oxygen concentration by consuming oxygen contained in the exhaust gas.
A tunnel kiln for firing ceramic porous bodies, the kiln comprising a preheating zone, a firing zone, and a cooling zone and driving a carriage loaded with ceramic porous bodies through the tunnel kiln, wherein the preheating zone is set to a low-oxygen atmosphere by providing an exhaust gas return line that supplies, into the preheating zone, low-oxygen-concentration exhaust gas discharged from a heat storage regenerative burner employed as means for heating the firing zone, wherein the heat storage regenerative burner alternates between combustion and exhaust of gas from the firing zone such that heat from said gas is stored in a heat reservoir when exhausting said gas, and wherein the preheating zone has an oxygen concentration of 8% or less.
Dependencies are inferred from the claim text.