Air gap insulated exhaust pipe with branch pipe stub and method of manufacturing same
US6349468B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1998 |
| Grant date | Feb 26, 2002 |
| Priority date | — |
| Expiry date | Nov 30, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/4994
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method for manufacturing an air-gap-insulated exhaust pipe having a branch stub, as well as an exhaust pipe produced according to such a method and a tool for forming such an exhaust pipe. Two tubes are inserted into one another to form a double tube. The double tube is placed in a first internal high-pressure shaping tool, and exposed to internal high pressure fluid such that it expands to match the contours of the engraving of the first shaping tool, and a double-walled branch stub is blown out of the double tube. The partially formed double tube is then placed in a second internal high-pressure shaping tool, with the double tube being surrounded, between the two ends including the branch stub, circumferentially and throughout by a corresponding design of the engraving, by an expansion chamber. The outer tube is expanded between the outer tube and inner tube under high pressure up to a precise fit with the engraving of the second shaping tool to form an insulating air gap, with the end of the branch stub being supported externally without yielding via a second counterpunch. The finished double tube is removed from the second shaping tool and a cap area of the branch stub, conta…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.