This invention relates to sealing rings for sealing between relatively moveable parts of an engine.
In the majority of cases, sealing rings are essentially in the form of a C which is effectively closed in use by the bringing together, leaving a small gap of the free ends of the C, although in some turbine arrangements the ends may be turned over in opposite senses so that they can hook together, this is usually to ease assembly.
Rings are typically used in gas turbines, steam turbines and other turbo machinery as seals between non-rotating hardware, rings allow for transient motion of mating parts in radial and axial directions. The motion may be due to thermal transients or a mis-match in the coefficients of thermal expansion between the two stators.
Particularly in the field of gas turbines designs are arising in which at least one face of the groove, in which the sealing ring will sit, is open, for example the face may be castellated. In this situation it is known for an end to pass through the gap in this face with the result that the ring can become progressively “unscrewed” from the groove.
From one aspect the invention consists in the sealing ring for sealing between relatively moveable parts of an engine, the ring comprising an open C-body having opposed ends including respective formations engageable to complete the ring categorized in that the formations are shaped to overlap or engage to allow relative sliding sealing engagement over a range of operating temperatures.
It is particularly preferred that one formation is in the form of a tongue and the other is in the form of a groove and both formations extend generally circumferentially. The relative lengths of the tongue and groove are selected to provide the extent of sealing engagement mentioned above.
The formation having the tongue may further include a radially offset circumferentially extending wall along at least part of the tongue for limiting or preventing radial leakage.
The tongue may have an enlarged head and the groove may have a restrictive mouth, whereby the head, and hence the tongue, can be held captive against circumferential withdrawal from the groove. In this case the axial dimension of the groove is sufficiently large to allow the head to pass into the groove so that the two ends can be clipped together.
The ring may be an out springing ring or an in springing ring.
The invention includes an engine having a groove in a part for receiving a sealing ring wherein a part of at least one of the groove walls is incomplete and the groove contains a sealing ring as previously defined. Although the invention has been defined above it is to be understood that it includes any inventive combination of the features set out above or in the following description.
The invention may be performed in various ways and specific embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:
a) and 3(b) illustrate a particular form of turbine with
a) and 4(b) are respectively a side view and a plan view of the first embodiment of the sealing ring;
a) and 8(b) are side views and plan views of a third embodiment;
a) to 9(c) show different tongue head configurations for use in the embodiment of
a) and 12(b) are side views and plan views of the embodiment of
For clarity the views shown in
In
In
Number | Date | Country | Kind |
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0716406.4 | Aug 2007 | GB | national |
Number | Date | Country | |
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60957475 | Aug 2007 | US |