The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 09, 1988
Filed:
Jul. 23, 1986
Laszlo Masznyik, Dorsten, DE;
Ruhrgas Aktiengesellschaft, Essen, DE;
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.