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US 4,398,649 AGranted
Primary manway cover removal
AssigneeCombustion Engineering, Inc.
InventorThomas V. Labbe
Life of this patent
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AssigneeCombustion Engineering, Inc.
InventorThomas V. Labbe
Estimating the term…
A method and apparatus for removing and replacing the primary manway cover (18) which is secured to the shell (10) of a nuclear steam generator by a multiplicity of nuts (24) and studs (22), including the steps of removing two of the studs and replacing them with two overlength special studs (30); removing the nuts (24) from all of the other studs (22); unthreading the nuts (24) on the overlength studs (30) until the cover (18) is positioned outside the ends (28) of the other studs (22); attaching (44) a cable (40) to the periphery of the cover; removing one of the overlength studs (30); and pivoting the cover (18) on the other of the overlength studs (30) out of alignment with the manway opening while supporting it by means of the cable (40).
The method of removing a cover from an opening in a vessel, wherein the cover is secured onto the vessel by a plurality of studs whose inner ends are threaded into threaded openings in the vessel, with nuts threaded onto the outer ends, including the steps of removing a pair of substantially diametrically opposite studs and associated nuts, replacing them with two overlength special studs and nuts, removing the nuts from all of the other studs, unthreading the nuts on the overlength studs until the cover can be moved away from the shell a distance where its inner surface is positioned outside the ends of all of the other studs, attaching a cable to the cover, removing one of the overlength studs, and pivoting the cover on the other of the overlength studs out of alignment with the opening while partially supporting the cover by means of the cable.
In combination, a vessel, opening means in the vessel, a plurality of studs securing the cover onto the vessel, the studs having inner ends threaded into openings in the vessel, nuts cooperating with the outer ends of each of the studs, two of the studs which are substantially diametrically opposite each other being overlength, of such a length that when the nuts of the overlength studs are unthreaded a given amount, and the nuts on all of the other studs are removed and the cover moved away from the opening into contact with the nuts on the overlength studs, the inner surface of the cover is outside of the outer ends of all of the other studs, cable means attached to the periphery of the cover, guide means on the periphery of the cover to keep the cable from slipping off the periphery of the cover, and means for causing controlled pivoting about one of the overlength studs until the cover permits access to the vessel interior, after the other overlength stud and its associated nut has been removed.
Dependencies are inferred from the claim text.