Patent Application
20100072710
The subject matter disclosed herein relates to seals disposed between surfaces which may engage in relative movement with respect to one another.
A gas turbine engine includes multiple components requiring various seals to prevent undesirable leakage of either hot exhaust gas or compressed air. Axially adjoining components typically utilize a ring shaped, or annular seal compressed therebetween. The annular seal may be a complete 360 degree member or, it may be circumferentially split at one or more locations to allow for circumferential expansion of the seal due to thermal gradients experienced during the operation of the gas turbine engine. The annular seal is radially elastic so that it may freely expand with an adjoining component without restraint. However, each circumferential split interrupts the seal to form a gap that can result in a leakage site. Annular seals may also be axially elastic so that they may be axially compressed, between the adjoining components, for establishing an effective seal therebetween.
To reduce leakage through a circumferential split in an annular seal, one may employ a cover plate which is mechanically fixed to the seal member on one side of the gap and is in sliding contact with the seal member on the other side of the gap. Alternately, a two-ply seal configuration is known in which an inner seal member is disposed in sliding relationship within an outer seal member to span the gap and reduce leakage. Both configurations require multiple components as well as some type of mechanical connection therebetween. A commonly used method for connecting the components may include welding, which further adds to the complexity and cost of the seal. Additionally, the introduction of welds or other mechanical connections may introduce corresponding heat-affected zones. Weld joints are necessarily heat risers which must be accommodated in order to prevent excessive material stress which may affect the seal durability.
Accordingly, it is desired to improve such seals by eliminating multiple seal components as well as welding or other mechanical stress risers, and otherwise simplify the design and manufacture thereof.
An annular seal having a dimensional, transverse cross-section has first and second ends. The second end includes a necked-down portion which is received within the first end in overlapping engagement.
The invention, in accordance with preferred and exemplary embodiments, together with further objects and advantages thereof, is more particularly described in the following detailed description taken in conjunction with the accompanying drawings in which:
Illustrated in
In order to sealingly join the radially inner band 16 to the annular support flange 18, an annular seal 20, in accordance with an exemplary embodiment of the invention, is disposed therebetween to reduce or prevent leakage through the joint. The annular seal 20, is preferably formed of thin gauge sheet metal or other suitable material which has the appropriate strength, flexibility and formability. The annular seal 20 spans, in a radial direction, between the annular support flange 18 and the radially inner band 16. The seal may have various dimensionally transverse cross-sectional configurations such as E-seals, W-seals, V-seals or any other suitable cross-section.
Depending upon the application of the annular seal 20 it may be constructed of a single piece of material or it may comprise more than one annular segment. The annular seal 20 includes sealing surfaces 22, 24 that contact the radially inner band 16 and the support flange 18 thereby creating an effective seal therebetween. In an exemplary embodiment, the annular seal 20 comprises a single, circumferentially extending element 26 defining a first end 28 and a second end 30, as shown in detail in
In an exemplary embodiment of the invention shown in
As indicated above, the annular seal 20 may have any of a number of dimensional transverse sections and still employ the benefit of slidably nested, relative ends which may be formed by necking down the second end 30 so as to nest in the first end 28. For example,
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
