The present invention refers to a sealing ring for turbomachines, which is assembled from individual sealing segments, wherein springs are installed between the individual sealing segments and locking elements for retaining the sealing segments are provided at the parting joint of the turbomachine.
In rotating turbomachines, sealing elements of various types of construction are used for sealing different pressurized spaces. In the case of sealing between rotating and stationary machine components special sealing elements, which are movable in the radial direction and therefore can yield in the case of rotor vibrations or rotor deflections, are frequently used.
In this case, a distinction is essentially made between spring-type sealing segments, wherein springs press the sealing elements radially in the direction of the shaft, or so-called “retractable seals”. In this case, the springs are arranged between the segments so that a ring of sealing elements is pressed away from the shaft and only close as a result of the pressure drop across the place which is to be sealed during operation of the machine.
The technology with “retractable seals” is especially recommended for turbines in which during the starting and shutdown processes large relative movement between rotor and casing is to be expected. In this operating phase, the sealing elements are then sufficiently far away from the rotor, close at a specific pressure, and fulfill their function as sealing elements during operating conditions. In this case, the faultless and predictable function of the closing of the segments is important.
This function is especially hindered as a result of locking elements which are installed at the parting joint of the turbomachine and are necessary in order to secure at least the sealing segments which are arranged in the upper section of the casing of the turbomachine from falling out during installation.
In order to also ensure closing of the sealing segments at the parting joint where the sealing segments, in addition to contact faces in the locating joint, rub on a locking element in the parting joint, an adequate safety margin when rating the closing pressure is simply taken into consideration at the time. With a specific pressure difference, the friction is overcome and the segments close.
It is the object of the present invention to disclose a sealing ring of the type referred to in the introduction, in the case of which the closing behavior is significantly improved.
This object is achieved for the sealing ring which is referred to in the introduction by the sealing segments being interconnected in a form-fitting manner at the parting joint.
The closing behavior can be significantly improved if the sealing segments at the parting joint are constructed so that adjacent sealing segments in the upper and lower sections of the casing of the turbomachine interlock after installation.
In the case of a radial movement, the segments then act as one segment. As a result of the form-fitting connection of the sealing segments at the parting joint, the difference between the starting pressure, at which the first sealing segments move, and the closing pressure, at which the sealing ring is completely closed, is reduced and fretting during closing of the segments at the parting joint is avoided.
In the case of the sealing ring according to the invention, the sealing segment, which to start with moves without rubbing at the parting joint, carries along the other sealing segment. As a result, the friction force at the parting joint is distributed between two sealing segments. It can be shown that as a result of this the difference between beginning and end of the closing process compared with the known construction can be reduced by 30%.
An expedient development of the sealing ring according to the present invention is characterized in that the one end of the sealing segment at the parting joint has a projecting cylindrical pin which extends in the axial direction of the turbomachine and fits into a corresponding recess at the end of the adjacent sealing segment. This constitutes a particularly simple development.
An exemplary embodiment of a sealing ring according to the invention is subsequently described with reference to the attached drawing.
In the drawing:
It is to be seen that in the case of the known embodiment of the sealing ring the radial movement of the sealing segments at the parting joint is different, while in the case of the sealing ring according to the present invention a common radial movement of the sealing segments at the parting joint of the casing of the turbomachine takes place.
In conclusion, the advantages of the sealing ring according to the invention shall be summarized once more:
Faster closing of the segments, therefore smaller pressure range, in which a movement of the sealing segments takes place
Altogether lower pressure differences, starting from which the “retractable seals” technology is operable
Homogenization of the closing process, no sharp differences at the parting joint between upper section and lower section of the casing of the turbomachine
Reduced rubbing at the parting joint, consequently a reduction of the risk of fretting
Number | Date | Country | Kind |
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10 2007 016 104.4 | Apr 2007 | DE | national |
This application is the U.S. National Stage of International Application No. PCT/EP2008/053875, filed Apr. 1, 2008 and claims the benefit thereof. The International Application claims the benefits of European application No. 10 2007 016 104.4 DE filed Apr. 3, 2007, both of the applications are incorporated by reference herein in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2008/053875 | 4/1/2008 | WO | 00 | 10/2/2009 |