GB1380964A - Plugging of metal tubes - Google Patents

Abstract

1380964 Welding by pressure ASSOCIATED ELECTRICAL INDUSTRIES Ltd 19 Jan 1973 [22 Feb 1972] 8050/72 Heading B3R [Also in Division F2] A method of plugging a metal tube, e.g. a tubular hole in a metal plate, a tube having an end fixed in a hole in a metal plate or a free tube which is surrounded by a rigid support means during the plugging operation, comprises inserting into the tube a hollow substantially cylindrical metal plug 3 containing an explosive charge 10 and a body 9 located between said charge and a closed end of the plug for locating the charge in a desired position, the part of the plug adjacent the closed end being a sliding fit within the tube and the plug being of a reduced external diameter over part of its length adjacent its open end and the plug being inserted into the tube with its closed end innermost ; placing over the end of the tube an end cap 11 which is so shaped and arranged as to locate the metal plug coaxially with the tube and in a desired axial position, the plug being retained in the said position by retaining means 8 associated with the inner end of the plug, and a detonator 12 being supported in and located in abutment with the explosive charge by, either said end cap 11 or the body 9 and then detonating the charge to cause an explosion so that at least the outer surface of at least part of the length of the metal plug around the whole of its periphery is welded to the tube wall. In the arrangement shown the end of the plug 3 protrudes from the end of the tube and the end cap 11 has a recess 14 which fits over the plug end, and a spigot 15 which fits into the annular space between the tube wall and the reduced diameter portion of the plug. The change in diameter of the plug between the end portion 4 and the reduced portion 5 is gradual so as to avoid corners of weakness in the plug. The body 9 and the end cap 11 are of a material such that they are substantially undamaged by the explosion or as a result of the explosion will produce debris which can be easily removed, a low density polyethylene is preferred but wood or other plastics material may be used. As an alternative to the arrangement shown the detonator may be positioned in the body 9. In a second embodiment (Fig. 2, not shown) the plug is positioned wholly within the end of the tube and the end cap has a hollow spigot extending into the tube end.