Patent Application
20140133971
The subject matter disclosed herein relates to configurations that seal a rotating member to a housing and more specifically to sealing an outermost radial portion of the rotating member to the housing. Sealing components that move relative to one another create challenges. These challenges are exacerbated when clearance between the moving components is altered based upon operational conditions of the machine as happens between a shroud of a bucket and a casing of a turbine engine, for example. Industries that rely on such seals are therefore receptive to new systems and methods that improve sealing between parts moving relative to one another.
According to one aspect of the invention a rotating seal configuration includes a housing and a rotatable member rotationally mounted relative to the housing. The rotatable member has at least one portion defining an outer perimetrical face that is configured to contact the housing during operational conditions that cause a radial dimension of the at least one portion to increase. The at least one portion has opposing axial surfaces with each of the opposing axial surfaces being dimensionally axially nearer to the other of the opposing axial surfaces immediately radially inwardly of the outer perimetrical face than a furthest part of the outer perimetrical face.
According to another aspect of the invention a method of sealing a rotatable member to a housing includes rotating a rotatable member relative to a housing, contacting the housing with a portion of the rotatable member and cutting a groove in the housing with the portion while preventing contact between either of opposing axial surfaces of the portion and the housing.
According to another aspect of the invention a turbomachine component includes a rotatable member rotationally mounted relative to a housing. The turbomachine component has a portion defining an outer perimetrical face being configured to contact the housing during some operational conditions, the portion has opposing axial surfaces that are axially nearer to one another at positions radially inwardly of the outer perimetrical face than they are at the outer perimetrical face.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
Referring to
Contact between the portion 22 and the housing 14 while the rotatable member 18 is rotating causes the portion 22 to cut into the housing 14 thereby cutting an annular groove 34 into an inner radial surface 38 of the housing 14. The cutting of the groove 34 assures that annular clearance between the outer perimetrical face 26 and the housing 14 is reduced thereby forming a dynamic seal therebetween. Materials for the housing 14 and the portion 22 may be chosen to assure that more material is removed from the housing 14 than from the rotatable member 18 during cutting. In turbine engine applications, for example, the housing 14 is often made of thin metal sheets in the shape of honeycomb cells while the rotatable member 18 is fabricated of much thicker metal. As such the honeycomb housing 14 is sacrificial and is easily cut away by the rotatable member 18 when the portion 22 comes into contact therewith. The portion 22 in a turbine engine may be part of a shroud of a bucket or one of two or more teeth in a labyrinth seal of a rotor while the housing may be a stationary outer assembly of the turbine engine or another rotatable part that rotates at a different speed than that of the portion 22, for example.
Making the opposing axial surfaces 30, 31 nearer to one another immediately radially inwardly of the outer perimetrical face 26 than a furthest part 32, 33 of the rotating seal configuration 10 assures that the opposing axial surfaces 30, 31 do not come into contact with sides 42 of the groove 34. Such contact, if allowed to occur could have detrimental operational effects related to frictional engagement, heating and removal of additional material from either the housing 14 or the rotatable member 18 beyond that which is necessary, for example.
If the interference contact between the portion 22 and the housing 14 is due to radial growth only of the rotatable member 18 the sides 42 will be substantially orthogonal to a rotational axis of the rotatable member 18. If there is some longitudinal movement combined with the radial growth of the rotatable member 18 the sides 42 may have a frustoconical or even a curved conical shape. If a longitudinal component of motion is anticipated then the opposing axial surfaces 30, 31 can be made to recede axially a sufficient amount to assure they do not contact the housing 14 when cutting thereinto. It should be noted that the interference contact between the portion 22 and the housing 14 can also be due to a reduction in radial dimension of the housing 14.
Angles 46 and 47 are defined between the outer perimetrical face 26 and the opposing axial surfaces 30, 31 respectively. In the embodiment illustrated the outer perimetrical face 26 is parallel to a rotational axis of the rotatable member 18 (it should be noted, however, that outer perimetrical surfaces that are not parallel to the rotational axis of the rotatable member 18 are also possible). The angles 46 and 47 are less than 90 degrees and are therefore acute angles. Since the rotatable member 18 in
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While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
