Large refractory article and method for making

Abstract

A method of sintering large refractory ceramic articles is disclosed. The method includes supporting a green refractory body on a plurality of support plates, the support plates in turn being supported by a plurality of support members having arcuate upper and lower surfaces. A setter material is disposed between the green refractory body to be sintered and the support plates. As the refractory body is sintered, the density of the article increases. Concurrently, the dimensions of the body decrease, which shrinkage, unless otherwise accommodated, may cause fracture of the body. The support plates and the structure of the support members, move to prevent the development of detrimental stresses in the refractory body as it sinters.

Description

CLAIMING BENEFIT OF PRIOR FILED U.S. APPLICATION[0001]This application claims the benefit of U.S. Provisional Application Ser. No. 61 / 153,679, filed on Feb. 19, 2009. The content of this document and the entire disclosure of publications, patents, and patent documents mentioned herein are incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention is directed to a method of making a large refractory article, and in particular, large refractory blocks or forming bodies, such as an isopipe used in the manufacture of glass.[0004]2. Technical Background[0005]Large refractory articles (e.g. blocks) are often used in the manufacture of glass due to their superior resistance to the high temperatures experienced in the process, and the harsh chemical nature of molten glass. These articles are typically formed by first forming a green refractory body, then heating, or firing, the green body to drive off any moisture, burn off organic binders that ...

AI Technical Summary

Benefits of technology

[0014]In yet another embodiment, a method of forming a sintered refractory article, such as isopipe, is described comprising forming a green refractory body by isostatically pressing a powdered refractory material, positioning the green refractory body on a plurality of support plates in a furnace, wherein the support plates are supported by a plurality of support members and adjacent support plates are separated by gaps, each of the support members being a section of a cylinder. The green refractory body is then heated to form a sintered refractory article. During the heating the green refractory body contracts, causing the support plates to translate in response to the contraction of the green refractory body and the support members to rotate in response to the translation of the support plates. The method is particularly effective when producing articles wherein the longest dimension of the sintered refractory article is at least about 250 cm and/or a mass of the sintere

Problems solved by technology

However, for large bodies, frictional forces can create large stress in the body.

In some applications, the final sintered article is massive (e.g. having a mass in excess of 450 kg), and frictional forces can result in induced stresses that can fracture the body, either during the sintering, or later when the sintered article is used.

For sintered articles having a mass much larger than 450 kg, the ability to sinter the precursor green body is significantly compromised., i.e. there is a increasing tendency for the sintering to produce cracks in the body.

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