Method and device for preparing an existing buried conduit for replacement by a new conduit
US4723873A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 23, 1986 |
| Grant date | Feb 9, 1988 |
| Priority date | — |
| Expiry date | Jul 23, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T225/371
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
To prepare an existing buried main made from a material which is tough at ambient temperature for replacement by a new main of the same or a larger size via a mole device by fracturing the existing main by compressive and impact forces and by widening the bore for the insertion of the new main that is clamped to the mole device, a liquefied gas having as low a boiling point as possible at atmospheric pressure is sprayed against the conduit wall from a cooling carriage that is pulled through the existing main prior to the movement of the mole device therethrough, thereby cooling the existing main to a temperature causing low-temperature embrittlement of the material of the existing main.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.