Metal fusion bonding – Explosive welding means
Patent
1982-11-18
1986-04-22
Ramsey, Kenneth J.
Metal fusion bonding
Explosive welding means
228119, 228175, B23K 2006
Patent
active
045836728
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates generally to an apparatus and method for securing; by welding, two coaxial tubes or a tubular sleeve coaxially within a fluid conduit.
There exists, in a variety of embodiments, fluid conduits which themselves are surrounded by a fluid environment. One such example is that of a tube and shell heat exchanger wherein a first fluid is contained within the fluid conduit and a second fluid surrounds the exterior of the conduit such that the heat exchange between the two fluids is effected. Such fluid conduits may from time to time develop leaks. These leaks permit fluid communication between the first and second fluids which may not be tolerable as in the case of a pressurized water nuclear steam generator where the fluids are substantially different pressures and one fluid contains radioactivity while the other does not. For this reason, fluid communication between the two fluids through a leak in the tube should be minimized.
When the fluid conduits are readily accessible, a variety of techniques may be employed to repair the ruptured conduit directly or to install a sleeve device or a plug into the conduit which stops the leak or completely isolates the entire conduit from a fluid source. However, in some environments, including that of a nuclear heat exchanger, it may be difficult for reasons of inaccessibility or biological hazard to effect such repairs. In such instances, techniques have been developed for plugging the fluid conduits from a remote location and thus totally removing them from service. Either rolling, explosive expansion and/or welding have been used to secure plugs in the tube ends. Roll expansion and welding are rather difficult to apply as remote operation and as a result explosive expansion has emerged as the most viable means of plugging tubes by remote operation.
A serious drawback to plugging both ends of a heat exchanger tube is that eventually as more and more tubes are plugged the capacity of the steam generator becomes less and less. Plugging requires removing an entire tube from operation when in general only a small localized zone of the tube is involved in the leak. Attempts have been made to install sleeving within the tube to isolate the portion of the tube which has degraded thereby stopping the leak. Those in the art have been primarily concerned with the development of an absolutely leak proof joint obtained by brazing, mechanical or explosive expansion, explosive welding or some other means, such as shown in U.S. Pat. No. Re. 30,802 (Rodgers), U.S. Pat. No. 3,140,537 (Popoff) and U.S. Pat. No. 3,402,870 (Carlson et al). However, in the past these metallurgical bonding techniques were not amenable to remote installation because of the need for cleanliness, close fittings, heat application and atmosphere control.
SUMMARY OF THE INVENTION
The present invention relates to a device and method of forming a metallurgical joint for welding coaxial tubes or securing a coaxially disposed tubular sleeve within a conduit. The explosive welding device to be used to weld repair sleeves to defective steam generator tubes comprises a cup member having explosive material secured therein, a plug attached to the cup member, said plug having remotely operable means for releasably securing the device at a predetermined position within the tube and a means for detonating the explosive material. In addition, the explosive welding device may also includes a means for centering the device within the defective tube. The invention further comprises the method of securing tubular sleeves within a fluid conduit comprising the steps of inserting and positioning the sleeve in the conduit. Thereafter applying an explosive force from within the sleeve and at one end thereof, sufficient to cause a portion of the sleeve and the inner wall of the conduit into contact with each other. A heating device is inserted into the sleeve to coincide with the expanded area and effect brazing of the sleeve to the conduit along the contacted area, and explosively w
REFERENCES:
patent: Re30802 (1981-11-01), Rogers
patent: 3158923 (1964-12-01), Reinsma
patent: 3744119 (1973-07-01), Hanson et al.
patent: 3868131 (1975-02-01), Zondag
patent: 3912148 (1975-10-01), Johnson
patent: 4028789 (1977-06-01), Loch
patent: 4106687 (1978-08-01), Bement
patent: 4117966 (1978-10-01), Green
patent: 4152821 (1979-05-01), Scott
patent: 4216893 (1980-08-01), Glatthorn
Bibb Henry Q.
Merker David E.
Stark Louis E.
Edwards Robert J.
Mai Robert C.
Muetterties J. Henry
Ramsey Kenneth J.
The Babcock & Wilcox Company
LandOfFree
Explosive welding device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Explosive welding device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Explosive welding device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1911105