Patent Number: 051679051
Section: abstract

Apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator. The invention includes an annular bracket sealingly attached to the rim of the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam that includes a first side section hingedly pivotably connected to a second side section for allowing the nozzle dam to be foldable. Removably connected to each side section is a center section, the center section and the side sections defining the generally circular nozzle dam for covering the opening defined by the annular bracket. The periphery portions of the center section and of the side sections have bores therethrough. A plurality of threaded bolts extend through the bores in the nozzle dam and into the threaded holes in the bracket for removably bolting the nozzle dam to the bracket. Interposed between the nozzle dam and the bracket is an elastomeric extrusion-resistant seal member having a plurality of apertures through the periphery thereof for receiving each bolt. As the nozzle dam is bolted to the bracket, a compressive force will act perpendicularly on the seal member. This compressive force will tend to cause the apertures of the seal member to extrude laterally outwardly away from each bolt, thus enlarging the aperture surrounding each bolt. Thus, the seal member is configured to effectively seal an imperfect seal surface and to resist extrusion such as by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is tightly bolted to the bracket. The extrusion-resistant feature of the seal member provides a nozzle dam that is fluid-tight because the aperture is not enlarged.