Metal working – Method of mechanical manufacture – Impeller making
Reexamination Certificate
1999-05-10
2001-02-20
Rosenbaum, Irene Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Impeller making
C029S402040
Reexamination Certificate
active
06189211
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and an arrangement for carrying out repair and/or maintenance work in the inner casing of a multishell turbomachine.
2. Discussion of Background
Depending on the pressure and temperature ratios to be expected, turbomachines are provided with single-shell or multishell casings. The requisite wall thickness of single-shell outer casings, in view of the thermal stresses, in particular at high pressures and temperatures, becomes relatively large. By the use of multishell casings, the effective pressure differences can be reduced and thus the wall and flange thicknesses can be reduced accordingly. In such multishell turbomachines, the inner casing carrying the blading is supported by the outer casing. In gas-turbine plants, such an inner casing may also accommodate the combustion chamber. As a result, the access required during repair and/or maintenance work to the various components arranged in the interior of the combustion chamber, such as, for example, the heat shields, the burners and their mountings, is not possible until after the opening of the outer casing and the subsequent opening of the combustion-chamber casing.
To avoid such time-consuming and costly measures in connection with the requisite repair and/or maintenance work, it is known to provide both the outer casing and the combustion-chamber casing of a gas-turbine plant with so-called manholes (see the article “Die Gasturbine GT13E2 ein richtungsweisendes Konzept für die Zukunft” in ABB Technik Jun. 7, 1993, pages 11-16, FIG.
3
). Through these manholes, either a fitter can get into the combustion chamber or another appropriately equipped tool carrier can be introduced. Of course, there must be sufficient space in the interior of the combustion chamber for this purpose, which is not always guaranteed. In addition, some extra design and constructional work is required in order to make a manhole in the combustion chamber in a functionally reliable manner, which results in at least increased total costs.
SUMMARY OF THE INVENTION
Accordingly, one object of the invention, in attempting to avoid all of these disadvantages, is to provide for multishell turbomachines a relatively simple, effort-saving and cost-saving arrangement and a corresponding method for carrying out repair and/or maintenance work in the inner casing of a multishell turbomachine.
According to the invention, this is achieved in in that, after a tool carrier is put into the outer casing of a turbomachine, the connecting elements of top part and bottom part of the inner casing are slackened. Finally, the top part of the inner casing is lifted in the outer casing to such an extent that the tool carrier can reach into the inner casing. To this end, at least one locating fixture for a lifting device is arranged on the top part of the inner casing. A radial distance is formed between the at least one outer casing and the inner casing, the radial distance corresponding to at least the radial extent of a tool carrier to be introduced into the inner casing.
Compared with multishell turbomachines whose outer and inner casings have to be opened during repair and/or maintenance work, the advantages of the invention lie in a considerable time saving, since now only the inner casing is opened. Removing the outer casing is no longer necessary for such work. Compared with turbomachines whose inner casing is inaccessible for maintenance work and which therefore also necessitate removal of the outer casing or which have manholes both in the outer casing and in the inner casing, which is possibly provided with a cooled lining, a marked cost reduction is achieved. In addition, access to the components of the turbine may advantageously also be gained through the combustion-chamber casing when required.
It is especially expedient if the locating fixture for the lifting device acts on the geodetically highest casing part of the inner-casing top part or on either side of this casing part. To this end, the at least one outer casing is provided with at least one aperture, in alignment with the locating fixture, for an actuating element connected to the lifting device. Alternatively, the locating fixture for the lifting device is fastened to the top part in the region of the parting plane of the inner casing or is arranged there at least on one side. In both cases, during repair and/or maintenance work, in addition to the appropriately equipped tool carrier, the lifting device is also introduced from outside through the at least one outer casing and fastened to the top part of the inner casing.
In an especially advantageous manner, the lifting device is firmly installed on the top part of the inner casing and therefore remains permanently in the interior of the outer casing once it has been fitted. Thus more time can be saved, since the lifting device no longer has to be introduced into the outer casing and fastened to the inner casing during repair and/or maintenance work.
REFERENCES:
patent: 4802821 (1989-02-01), Kreitmeier
patent: 4805282 (1989-02-01), Reaves et al.
patent: 5575145 (1996-11-01), O'Neill et al.
patent: 5870824 (1999-02-01), Lilja et al.
patent: 683970 (1939-11-01), None
patent: 1166110 (1964-03-01), None
patent: 0321809B1 (1991-05-01), None
patent: 2202588 (1988-09-01), None
patent: 802566 (1981-02-01), None
“Die Gastrubine GT13E2—ein richtungweisendes Konzept fur die Zukunft”, Viereck, ABB Technik Jun. 7, 1993, pp. 11-16.
Asea Brown Boveri AG
Burns Doane Swecker & Mathis L.L.P.
Cuda Rosenbaum Irene
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