Ngk Insulators, Inc.

Jotaro Miyata

Chikashi Ihara

Takashi Yasue

Takashi Goshima

Ihara Chikashi

Yasue Takashi

The invention provides a shuttle kiln that can fire ceramic porous bodies containing organic binders in a shorter period of time than in conventional methods without occurring breaks due to a temperature difference between the inside and the outside. The shuttle kiln of the invention is suited for firing of ceramic porous bodies containing organic binders. It includes a gas suction paththat suctions in-furnace gas and discharges it via an afterburnerand a circulation paththat suctions the in-furnace gas to the furnace outside to burn organic binder gas and then returns it into the furnace.

Shuttle kiln for firing ceramic porous bodies

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, a firing zone, and a cooling zoneand fires the ceramic porous bodies loaded on a carriageby driving it in a furnace. A heat storage regenerative burneris used as means of heating the firing zoneso that low-oxygen-concentration exhaust gas discharged from the heat storage regenerative burnermay be returned to an exhaust gas return lineand supplied into the preheating zone. The exhaust gas return linemay be provided with a combustion devicethat reduces the oxygen concentration by consuming oxygen contained in the exhaust gas.

Tunnel kiln for firing ceramic porous bodies

There is provided an electric heater support plate which is not likely to be softened or deformed during firing at a high temperature, even if a material to be fired contains an alkaline component or an Si component as a volatile component. A passagefor the material to be fired surrounded by a ceiling refractory, wall refractoriesand a floor refractoryis provided with an electric heaterheating from above and an electric heaterheating from below. This electric heaterhas at least its heating partmounted and supported on a fire-resistant support plate, and this support platein this invention has a two-layer structure in which an insulating ceramic support plateis laminated on an SiC-based ceramic plate. The two-layer structure support platesare supported by refractoriesinstalled in a furnace and are arranged in parallel in a plurality of rows in a longitudinal direction of the furnace, and the electric heatermounted on the support plates is so constructed as to generate heat by an electric power supplied from an energizing terminalexposed to the outside of a furnace wall.

Support structure of heater

A to-be-burned object including a metal Si component or SiC or SiNcan be burned in such a manner that vaporized SiO can be safely exhausted without causing SiO attached to a wall of a furnace or an inner face of an exhaust duct. An exhaust method of a continuous furnace for continuously burning a to-be-burned object containing a metal Si component or highly-fire-resistant SiC or SiNincludes steps of 1) exhausting in-furnace gas including SiO vaporized during a burning process. An exhaust ductused for this exhaust is provided at an upper part of a side wallof the furnace having a higher temperature (1300 degrees C. or more) than a concentration temperature of SiO vaporized during a burning process. 2) oxidizing the exhausted SiO at the outside of the furnace to detoxify SiO. The in-furnace gas exhausted by the exhaust ductis guided to an exhaust pipeconnected to an outlet of the exhaust ductat the outside of the furnace. This exhaust pipeincludes oxygen supply holesand. By sending oxygen supplied from an appropriate oxygen supply source into the exhaust pipe, SiO guided to the exhaust pipereacts with oxygen and is detoxified.

Growing community of inventors

Komaki, Japan

Jotaro Miyata