Ngk Insulators, Inc.

Koji Ogura

Kazuhiro Miyahara

Keiji Yasuda

A process for firing ceramic shaped bodies is disclosed, which comprises the step of making a heating temperature in a temperature range up to a decomposing temperature of a shaping aid contained in the ceramic shaped body smaller than that in a temperature range from the decomposing temperature to a firing temperature. A tunnel kiln is also disclosed, which comprises a preheating zone, a firing zone, a waste heat zone, combustion burners provided at the firing zone, an exhaust means provided at an inlet side of the preheating zone for evacuating combustion gases from the combustion burners outside the kiln, and another exhaust means provided at an outlet side of the preheating zone for evacuating the combustion gases outside the kiln.

Process for firing ceramic shaped bodies and a tunnel kiln used therefor

A tunnel kiln for firing molded ceramic green products includes a gate for feeding a kiln car into and out of the kiln. The gate located at low temperature parts of the kiln includes side walls made of a stainless steel having inclined surfaces and a ceiling made of a stainless steel and having inclined surfaces toward the side walls. The tunnel kiln further includes sand seals at connections between the side walls and the ceiling and receiving bases provided under lower ends of the side walls for receiving pyrolytically decomposed products. The side walls are formed with exhaust ports communicating with the receiving bases so that the pyrolytically decomposed products flow along the inclined surfaces of the ceiling and the side walls are once collected in the receiving bases and exhausted through the exhaust ports of the side walls to the outside of the kiln. With this arrangement, defective ceramic products due to decomposed products attached thereto are completely eliminated.

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Chiryu, Japan

Koji Ogura