Bushing construction
US4146373A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1977 |
| Grant date | Mar 27, 1979 |
| Priority date | — |
| Expiry date | Dec 23, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S65/04
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Improved construction for bushings used to produce glass fibers is provided. Such bushings commonly have thin side and end walls of precious metal defining a glass-melting chamber, with a bottom in which fiber-forming tips are located. Refractory material is located around the side and end walls. When the bushings are heated to operating temperatures, the metal walls tend to expand more than the refractory material and, particularly with larger bushings, the walls can buckle and crack since full expansion of the walls is prevented by the refractory material. To overcome this, it has been found that the bushings can be constructed with space between the metal walls and the refractory, with the space equalling the difference in expansion of the two materials. The space is formed by layers of heat-removable material, such as wax which melts out as the bushings are heated. When the bushings are at operating temperature then, the metal walls expand into the space and come into contact with the surrounding refractory material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.