MXPA00004260A - C-shaped ring seal - Google Patents

Abstract

A seal (30) includes first and second axially opposite loops (32, 34) integrally joined together by a coextensive web (36) in a collective ring having a circumferential split. The two loops are arcuate in section, with radially outer and inner sealing lands (40, 42, 44, 46). And the web (36) is disposed radially between the outer (40, 44) and inner (42, 46) lands. The loops (32, 34) are disposed in corresponding grooves of adjoining members (24, 26) for effecting a seal therebetween and accommodating differential radial and axial thermal movement.

Description

RING SEAL IN THE FORM OF C BACKGROUND OF THE INVENTION The present invention relates generally to gas turbine engines, and, more specifically to seals therein. In a gas turbine engine, the air is pressurized in a compressor, mixed with fuel in a combustor, and ignited to generate hot combustion gases that flow downstream through many stages of the turbine that draw energy from the same The pressurized air surrounds the combustor and is used to cool the coatings thereof. Pressurized air is also used to cool other engine components. Since the motor is formed of stator components that are properly joined together, various types of static seals must be provided therebetween to reduce or prevent undesirable leakage of either pressurized air or hot combustion gases. The seals have different configurations in cross section to specifically seal different components. For example, the stamps may have a W-shaped cross section, or an E-shape, or simply circular cross sections depending on the specific application requiring the seal. Some seals are complete rings, or they can be circumferential separations in a location to eliminate undesirable tangential stresses in them. Another type of seal is in the form of a straight, flat laminated seal placed in complementary slits between the attached components. The seals undergo several differential thermal movements between the attached components including differential radial movements, differential axial movements, or both. Relative radial and axial deviations are common between the rear end of the outer jacket of the combustor and the forward end of the outer band of the attached high pressure turbine nozzle. Under the high temperature of the combustion gases produced in the combustor, the outer coating can expand radially outwardly significantly more than the radially outer expansion of the outer band. And, the axial space between the two components can grow substantially large during the operation. Also, a laminated seal shape is used in this location in which a radial laminate seal engages a complementary radial groove to accommodate differential radial movement, and an axial laminate seal engages a complementary axial groove to accommodate differential axial movement. However, since the laminated seals are straight in cross section and can deform during operation, their sealing capability can be contained. In addition, some laminated seals are provided in segments, which interrupt the sealing capacity between the segments. Also, it is desired to provide an improved ring seal to seal the high excursion differential radial and axial movement between the stator components of the gas turbine engine.

BRIEF DESCRIPTION OF THE INVENTION A seal includes first and second axially opposed loops, integrally joined together by a coextensive tape in a collective ring having a circumferential spacing. The two loops are arched in section, with radially outer and inner sealing valleys. And, the tape is disposed radially between the outer and inner valleys. The loops are arranged in corresponding grooves of adjoining members to effect a seal therebetween and accommodate differential radial and axial thermal movement.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, in accordance with the preferred and exemplary embodiments, in addition to the additional objects and advantages thereof, is more particularly described in the following detailed description which is included together with the accompanying drawings in which: Figure 1 is a view in axial section through a portion of a gas turbine engine having a seal of conformity with an exemplary embodiment between an outer jacket of the combustor and an outer band of the turbine nozzle. Figure 2 is a front view, in elevation of the ring seal 5 illustrated in FIG. 1 in accordance with an exemplary embodiment of the present invention. Figure 3 is an axial sectional view, amplified through the ring seal mounted between the outer skin and the band of Figure 1 within the dashed circle marked with the number 3. Figure 4 is an isometric view of a portion of the ring seal illustrated in Figure 3.

DETAILED DESCRIPTION OF THE INVENTION In Figure 1 there is illustrated a portion of a gas turbine engine 10 that is axesymmetrically about a longitudinal or centerline axis 12. The engine includes a multi-stage axial compressor (not shown) for pressurizing air 14 which is channeled to an annular combustor 16 where it is mixed with the fuel and ignited to generate hot combustion gases 18. The combustor 16 is mounted within a combustion chamber enclosure 20 and discharges the combustor gases 18 into a nozzle of the downstream high pressure turbine 22. The high and low pressure turbines (not shown) that draw energy ^^^^^^^? ^^^^^ é ^ gl ^ ^^^ ^^^ gf Me ^^^^^^ Í of combustion gases to drive the compressor mechanically, and typically also mechanically operated one fan to produce propellant to mechanically actuate push an aircraft in flight, are placed down stream desdß nozzle 22. the combustor 16 5 includes a radially outer liner 24 which defines an outer boundary for the combustion gases 18. the nozzle the turbine 22 includes a radially outer band 26 defining a radially outer boundary for the combustion gases within the nozzle that are channeled between a plurality of nozzle vanes circumferentially spaced 28 extending radially inwardly from the outer band 26. The combustor also includes a radially inner liner cooperating with a radially inner band of the nozzle to define a path limit radially inner flow for gases as they flow from the combustor to the nozzle. Since the combustor and nozzle are separately manufactured components, assembled together should the engine and suitably sealed to prevent leakage of the pressurized air flow 14 or the combustion gases 18. During operation, a portion of the air pressurized 14 surrounds the combustor within the enclosure 20 and typically has a higher pressure than that of the combustion gases 18 therein. To prevent undesirable leaks of the pressurized air 14 radially inward in the flow path of the combustion gas between the -. ^ .- ^. ^ ~ - & - - - », .. combustor and the nozzle, a ring seal 30 is formed between the outer skin 24 and the outer band 26. However, for the ring seal 30 placed between the outer skin and the outer band, the motor 10 can be otherwise conventional in terms of construction and operation. The sealed junction between the outer coating and the outer band is subjected to relatively high excursions both radial and axial due to the thermal expansion and shrinkage caused by the hot combustion gases 18 during operation. Likewise, the seal 30 is configured in accordance with the present invention to accommodate the axial and radial excursions raised in this location in a relatively simple and efficient design that maximizes the sealing effectiveness thereof. More specifically, the raised excursion ring seal 30 is illustrated separately in FIG. 2, and in amplified section in FIG. 3. The seal includes first and second axially opposed loops 32, 34 integrally joined together in a unitary component by a tape or coextensive diaphragm 36 in collective seal ring having a circumferential gap or space 38, as shown in figure 2. the spacing 38 interrupts the circumferential extent of the seal ring at one location to prevent the generation of tangential stress not desirable in it. The ring seal is illustrated more particularly in Figures 3 and 4. The first loop 32 arches in cross section, with first radially outer and inner sealing valleys 40, 42 extending circumferentially around the ring. Similarly, the second loop 34 arcs in cross section, with second radially outer and inner sealing valleys 44, 46 also extending circumferentially around the ring. The belt 36 is positioned radially between the outer and inner valleys of the first and second loops in a compact cross section with reduced bending moment of inertia to maintain the seal ring flexibility and allow it to rotate during operation under high differential radial heat movement between the outer skin 24 and the outer band 26. As shown in Figure 4, for example, the first and second loops are preferably axially outwardly convexly spaced apart, and axially inwardly concave with each other, and radially aligned or in a coextensive manner. The first and second loops also separate axially from each other, with the tape 36 extending axially therebetween. In the preferred embodiment illustrated in Figure 4, the ribbon 36 is integrally joined to the first and second inner valleys 42, 46 of the opposite loops, and the loops are not otherwise joined together in the first and second outer valleys 40, 44 which are simply axially separated by the axial extension of the belt 36. In a preferred embodiment, the first and second loops are semicircular in section, and the belt 36 is mainly straight in axial cross section. The first and second loops and the integral tape are preferably formed of thin gauge, undrilled metal sheet in one or more laminated materials as desired. Two nested sheet metal sheets are laminated or folded is illustrated in Figure 4 so that the inner sheet can extend through the circumferential spacing 38 illustrated in Figure 2 to slidably engage the outer sheet and lay a bridge in the gap to improve sealing therebetween while allowing a non-limited circumferential expansion and contraction of the ring seal 30. As shown in Figure 3, the ring seal 30 is mounted between the outer shell 24 and the band. outer 26 with first and second loops 32, 34 that are axially aligned with each other in equal radii from the centerline of the motor. The belt 36 is preferably separated radially outwardly from the first and second inner valleys 42, 46 and radially inward from the first and second outer valleys 40, 44 to provide flexibility in the ring seal 30 by reducing its moment of inertial bending. Despite its specific cross section, the seal 30 is not a complete ring except for the circumferential separation 38, and operates with three degrees of freedom. The axial cross section of the partial rail of the seal according to the present invention provides an effective seal between the outer skin and the outer band as it accommodates excursions • * is »*;,« • i * '-. * JB ?? high differential in the radial and axial direction, without the seal significantly limit the differential movements, and without experiencing excessive loads and reaction stresses in it. More specifically, the outer sheath 24 illustrated in Figure 3 defines a first annular member through which the combustion gases 18 are channeled, and includes a first annular seat or groove that faces axially rearward 48 at the rear end thereof. the first loop 32 is received in sliding contact therein in a tongue and groove sealing arrangement. Likewise, the outer band 26 defines a second annular member placed coaxially with the outer skin 24, and has a second annular groove or seat axially facing forward 50 at its forward end which receives in sliding contact therewith the second loop 34 in a tongue and groove sealing arrangement. The outer coating 24 and the outer band 26 are axially spaced apart in the first and second slots 48, 50, and the belt 36 extends axially therebetween. The sealing is performed during the operation mainly by contacting the first inner valley 42 against the lower part of the first groove 48 around the circumference thereof, and by contacting the second inner valley 46 against the lower part of the groove. the second slot 50 around the circumference thereof. The intermediate tape 36 is not perforated and reacts the differential pressure radially through the seal which improves the sealing contact between the ^^^ g¡HH¡ first and second interior valleys 42, 46 and their seats. In addition, the first and second outer valleys 40, 44 are also available to effect corresponding seals with the upper portions of the respective slots 48, 50 as required. The differential axial thermal movement caused by expansion or contraction is illustrated in FIG. 3 in the excursion of the imaginary line of the outer band 26 in the axial direction designated A. This axial size of the slots 48, 50, and the extension Axial of the belt 36 are selected to ensure that the first and second loops 32, 34 always remain within their corresponding grooves in sealing contact without considering the amount of differential axial movement between the outer coating 24 and the outer band 26. The movement Differential radial B is also illustrated in Figure 3 by the different radial positions of the outer sheath 24 shown in the imaginary line. To accommodate the differential radial excursion between the two components, the ring seal 30 will coil in the radial direction while the first and second loops 32, 34 remain in sealing contact in their respective slots 48, 50. Since the seal 30 is a annular member, sufficient torsional flexibility must be provided therein to permit high radial excursion without limitation or excessive distortion thereof leading to excessive strain or deformation of the plastic. The asymmetric loops and the intermediate tape 36 interrupt the section perimeter to increase its 1 Torsional flexibility in a compact arrangement providing high axial and radial excursion capability. As indicated above, the belt 36 separates between the respective outer and inner valleys to minimize the radial moment of inertia which increases the bending or twisting thereof. And, the belt 36 is generally concave radially inwardly in section to allow differential radial movement between the outer shell 24 and the outer band 26 without interference therewith. As shown in Figure 3, the belt 36 is preferably straight in axial section, and is bent into two planar sections from its midpoint having a suitable bending radius, with a radially inner surface of the belt having a slightly obtuse included angle less than 180 ° to increase both the torsional flexibility and allow radial differential movement between the first and second loops 32, 34 without the tape 36 engaging the corresponding portions of the first and second slots 48, 50. For example, while the first loop or left loop 32 illustrated in Figure 3 is transported radially outwardly with the outer coating 24 during expansion thermally at a point greater than that of the outer band 26, the left loop will rotate slightly clockwise in the left slot 48 with the left portion of the tape 36 moving close to the bottom of the left slot. Also, the second loop or right loop 34 will also rotate clockwise in this example, with the right portion of the tape 36 moving outward from the bottom of the right slot 50. While this occurs, the stamp 30 is elastically threaded through the belt 36 to place the opposite loops 32, 34 at different radii from the axis of the motor center line. The use of the ring seal 30 between the outer cladding 24 and the outer band 26 accommodates both the high excursion radial travel and the axial movement therebetween in a simple compact and relative configuration. The outer skin 24 primarily requires a first groove that faces axially towards the individual back 48, and the outer band 26 primarily requires the second groove facing forward axially individual 50. The double-function ring seal 30 is placed in both grooves to accommodate differential axial movement therebetween as well as differential radial movement while maintaining an effective seal in both loops 32, 34. Low axial movement differential, the ring seal 30 has a common non-deformed radius between two end loops and simply slides axially into the two slots while maintaining an effective seal. In addition, the same configuration allows the ring seal 30 to be elastically threaded to allow the first and second loops 32, 34 to be radially separated while being transported into the grooves. , 48, 50 at different radial positions under differential thermal growth. The elastic band 36 therefore builds a bridge together with the first and second loops 32, 34 to allow this double capacity. Tape 36 is preferably positioned at the radially inner ends of the loops to minimize the stiffness of the seal. However, in an alternative embodiment, the ribbon 36 may if desired be joined to the first and second outer valleys 44, 46. Although what has been described herein are what are considered the preferred and exemplary embodiments of the present invention, other modifications of the invention will be apparent to those skilled in the art from the teachings thereof, and it is therefore desirable to secure such modifications in the appended claims while within the spirit and scope of the invention. Likewise, what is desired to be assured by the United States patent letter is the invention as defined in the appended claims.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A seal comprising: first and second axially opposed loops integrally joined together by a coextensive tape in a collective ring having a circumferential separation; said first loop is arcuate in section, with radially outer and inner sealing valleys; said second loop is arcuate in section, with radially outer and inner sealing valleys; and said tape is disposed radially between said outer and inner valleys of the first and second loops.

2. The seal according to claim 1, further characterized in that the first and second loops are convex axially outward and are axially separated from each other, with said tape extending axially therebetween.

3. The seal according to claim 2, further characterized in that said belt separates radially outwardly from said first and second valleys internally and radially inwardly of said first and second outer valleys.

4. The seal according to claim 3, further characterized in that said belt is integrally joined to said first and second interior valleys.

5. The stamp according to claim 3, further characterized in that said first and second loops are semicircular.

6. The seal according to claim 3, further characterized in that said first and second loops and tape are sheet metals.

7. The seal according to claim 3, further characterized in that it comprises: a first annular member for channeling a fluid, and having a first annular groove axially facing in sliding contact in said first loop; and a second annular member placed coaxially with said first member, and having a second slot 10 annular axially facing in sliding contact in said second loop.

8. The seal according to claim 7, further characterized in that said first and second members are axially separated from each other in said first and second slots thereof, and said tape extends axially therebetween.

9. The seal according to claim 8, further characterized in that the tape is concave radially inwardly in section to allow differential radial movement between said first and second members without interference thereof.

10. The stamp according to claim 9, 20 further characterized in that said first member is an outer coating of the gas turbine engine combustor for channeling hot combustion gases therebetween; and said second member is an outer band of the nozzle of the turbine of the gas turbine engine that is attached MMt-aa by sealing said outer sheath by said sealing ring to accommodate both differential radial and axial movement therebetween due to said combustion gases. ^ ¡^ ^ * YM gg ¡ágá a ^^ ¡^^^^^ a¡¡