Metal working – Impeller making apparatus
Reexamination Certificate
2001-11-30
2003-11-18
Cuda-Rosenbaum, I (Department: 3726)
Metal working
Impeller making apparatus
C029S889210, C029S889220
Reexamination Certificate
active
06647602
ABSTRACT:
FIELD OF TECHNOLOGY
The invention relates to a fixation device for blading of a turbo-machine, in which, longitudinally to a mounting groove, a plurality of blades is positioned and in which, between at least two blades positioned adjacent to each other inside the mounting groove, a mounting gap is provided, having two insertion elements constructed as collar halves that can be inserted into the mounting gap, and each of which has a width adapted to the width of the mounting gap and which enclose between themselves a gap space into which a wedge element can be inserted that can be wedged in such a way that both collar halves are fixed in a force-derived manner by means of the wedge element inside the mounting groove.
STATE OF THE ART
Bladings of the previously described type are related to guide blades, but in particular to rotating blades inside turbo-machines, such as, for example, the compressor or turbine stage of a gas turbine system. The following explanations relate preferably to rotating blades provided longitudinally to a mounting groove provided inside the rotor of a turbo-machine and extends around it along its circumference, and which rotating blades must be positioned in a suitable manner with respect to the respective flow conditions and must be reliably secured against potential maladjustments during the operation of the turbo-machines, but in particular against a complete detachment from the mounting groove. The measures to be instituted with respect to the rotating blades, as described below, can also be used, however, for the guide blades integrated in the stationary housing components of turbo-machines.
The risk of a complete detachment of individual rotating blades from the respective mounting means exists if the rotating blades inserted inside the mounting grooves and attached in an actually known manner are able to move unevenly within the respective mounting play circumferentially along the mounting groove on the rotor. Such peripheral maladjustments in a plurality of rotating blades inserted along the mounting groove may result in a significant gap being created between two adjoining rotating blades, said gap being large enough so that a rotating blade is able to detach itself by radial twisting from the mounting groove, resulting in substantial damage to the entire turbo-machine system.
In general, actually known means for securing against an autonomous detachment of individual rotating blades from the mounting groove relate to the reduction of the play in circumferential direction between two adjacent blade roots within the mounting groove. After installing all rotating blades inserted into the mounting groove, as well as all whole and halved intermediate pieces, a gap is created between, for example, two adjacent rotating blades facing each other inside the mounting groove, this gap being the so-called mounting gap, into which is inserted a so-called rotor collar that ensures that the play between the rotating blades set into the mounting groove and between the intermediate pieces is minimized.
An actually known rotor collar is described below in reference to
FIGS. 2
a
-
2
c
.
FIG. 2
a
shows a cross-section through a mounting groove
1
fabricated within a rotor
2
. With respect to the mutual attachment of two rotating blades
31
,
32
positioned immediately adjacent to each other within the mounting groove
1
(see top view according to
FIG. 2
c
), the so-called rotor collar
4
is inserted radially between the two blades
31
,
32
in the mounting groove
1
. As illustrated in detail in
FIG. 2
b
, the rotor collar
4
consists of two so-called collar halves
41
,
42
as well as a wedge element
43
. The sides of the collar halves
41
,
42
, which each face towards the mounting groove
1
, are appropriately designed for a force-derived and shape-mated engagement with the internal contour of the mounting groove
1
. In the inserted condition within the mounting groove
1
, both collar halves
41
,
42
enclose a gap
5
, into which the wedge element
43
can be inserted in a radial direction. In the top portion, the collar halves
41
,
42
have a corresponding recess
6
(see
FIG. 2
b
), each of which is similar to the shape of half a heart, in which the retention tabs
44
of the wedge element
43
are permanently spread according to the illustration in
FIG. 2
a
, in order to permanently spread both collar halves
41
,
42
against the inside contour of the mounting groove
1
.
Because of the different thermal expansion behaviors between the blades, the rotor collar, and the rotor, a play is created during operation between the blades and the intermediate pieces inside the mounting groove, including the rotor collar. Because of the resulting circumferential play, the collar halves may shift in relation to one another in a circumferential direction along the mounting groove so that the spread wedge element is able to detach itself from the heart-shaped recesses. Such a case would again result in the initially described damage scenario.
DESCRIPTION OF THE INVENTION
The objective therefore is to further develop a fixation device of this type, as illustrated, for example, in
FIGS. 2
a
-
2
c
, in such a way that the previously described damage scenario can be excluded. The respective measures should be as simple as possible in their construction and should be economical to realize.
The realization of the objective of the invention is disclosed in claim
1
. Characteristics that advantageously further develop the concept of the invention are the subject of the secondary claims and in particular of the specification, in reference to the figures.
According to the invention, a fixation device according to the preamble of claim
1
, for example a fixation device of this type as referenced in
FIGS. 2
a
-
2
c
, is constructed in such a way that the wedge element is provided with at least one connecting element towards the side of a blade and that at least one of the two blades adjoining the wedge element is provided with a counter-contour corresponding to the connecting element, so that the wedge element and the blade enter into an intimate shape-mated connection with each other.
The idea on which the invention is based is the creation of an intimate shape-mated connection between the wedge element and at least one immediately adjacent rotating blade, so that no relative movements between the rotating blade and the wedge element and, related to this, the entire rotor collar are able to occur, so that the initially described risk potential with respect to the detachment of the wedge element can be decisively limited.
In an especially advantageous manner, the wedge element is connected with the two immediately adjacent blades via respective shape-mating connecting elements. Such a design of a fixation device according to the invention is explained below in reference to the figures.
REFERENCES:
patent: 3721506 (1973-03-01), Anderson
patent: 5961286 (1999-10-01), Schaub et al.
patent: 6126357 (2000-10-01), Alkelin et al.
patent: 6439841 (2002-08-01), Bosel
patent: 6517313 (2003-02-01), Rogers
patent: 2003/0002987 (2003-01-01), Davidson
patent: 2003/0012654 (2003-01-01), Strassberger et al.
Bachofner René
Kappis Wolfgang
Rihak Pavel
Thueringer Ferdinand
Waltke Ulrich
Alstom (Switzerland Ltd
Burns Doane Swecker & Mathis L.L.P.
Cuda-Rosenbaum I
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