CN101113677A

CN101113677A - Air suction labyrinth type seal element

Info

Publication number: CN101113677A
Application number: CNA2007101362866A
Authority: CN
Inventors: W·L·赫伦; J·C·阿尔伯斯; C·C·格林; P·克鲁金顿
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2006-06-10
Filing date: 2007-06-11
Publication date: 2008-01-30

Abstract

The sealing element body (48) includes the following components: an annular axial-extending part (72); a radical extending part (70) which forms a main sealing surface (50) and fits with the axial-extending part (72) and forms an approximately L-shaped section plane; and at least one annular axial-extending sealing tooth (88).

Description

Air-breathing labyrinth

Technical field

The present invention relates in general to the face seal that is used for rotating machinery, and particularly air-breathing or gas equilibrium face seal.

Background technique

Face seal is used for reducing the seepage in slit between two parts, and this seepage arrives low pressure area from the zone of high pressure.This Sealing has been used to rotating machinery, such as steamturbine and gas turbine.

In gas turbine, face seal is used between static equipment room, rotor and stator component, and can be used between different swivel assembly.Slit between these different parts or leakage path must be sealed, and employed Sealing needs to compensate the various variations in the slit that elongation owing to difference heat that produces between the operation cycle at lathe and mechanical component causes.

The usually contact by between parts, keeping being obedient to (such as, use brush seal or leaf formula Sealing) thus or reduce flow (such as adopting labyrinth) and adapt to variable gap to be sealed by setting up the compound leakage path that can cause the pressure loss.Labyrinth (space closure under the extreme case) between rotation and fixed component can be regulated by allowing the soft stator matrix (" can wear and tear ") of rotor labyrinth teeth friction.Because initial slit, and because the contacting of Sealing and approximal surface, do not have in these Sealings a kind ofly can satisfy needed over-all properties and durability.

For instance, Fig. 1 illustrates the part of gas turbine, and this gas turbine comprises rear end, diffusing tube 12, the annular combustion chamber 14 of compressor 10 and comprises the high-pressure turbine 16 of fixed nozzle 18 and the rotary turbine blade 20 that supports by turbine rotor 22.Compressor 10 is driven by axle 24 by turbine 16.Space between elementary flow path of hot gas " F " and the axle 24 forms the secondary flow path.Because comprise maximum efficiency and avoid various reasons such as wearing and tearing, wish that control as far as possible passes through the seepage in secondary flow path.Utilization comprises and one or morely reduces or hinder the Sealing that flows to realize these purposes.In illustrated embodiment, Compressor Discharge Pressure (CDP) black box 26 is arranged on the inboard of diffusing tube 12, and sealing assembly 26 comprises having and is positioned at the fixedly rotary component 28 of a plurality of annular seal teeth 30 that extend radially outwardly on wearout parts 32 opposites.Environment seal forward (FOS) 34 is arranged on the inboard of turbine nozzle 18, and sealing part 34 comprises having and is positioned at the fixedly rotary component 36 of a plurality of annular seal teeth 38 that extend radially outwardly on wearout parts 40 opposites.Face seal also is used for other positions of motor.Compressor Discharge Pressure (CDP) black box 26 and the above-mentioned extended operation meeting wearing and tearing of environment seal (FOS) 34 processes forward.

Summary of the invention

The invention provides a kind of face seal with low seepage and high-durability.Gap between the may command seal element is not so that the tooth of Sealing can the drag seal rotor.This is at the motor manufacturing time and effective sealing is provided later service time.Estimation is compared with existing face seal technology, and it can make the seepage on primary seal surface reduce about 25%.

According to an aspect, black box provided by the invention has: first annular element that forms the first primary seal surface of axially facing usually; With second annular element on the second primary seal surface of common formation axially facing, this second annular element be installed on the seal holder by axially movable relation in case second primary sealing area in the face of the first primary seal surface arrangement; Wherein at least one in first primary seal surface and the second primary seal surface has at least one from its axially extended annular seal tooth.

According to a further aspect in the invention, being arranged in the seal body that is used for black box around the axis comprises: an annular, extend axially part; One forms the radially extension on primary seal surface and extends axially part with this and cooperates the roughly L shaped section of formation; With at least one from the axially extended annular seal tooth in primary seal surface.

According to a further aspect in the invention, being positioned at the black box that is used for gas-turbine engine around the axis comprises: the rotor with first primary seal surface of axially facing; Be positioned near the fixing seals support of this rotor; Between this rotor and sealing part support and be attached to the annular seal body of sealing part support, sealing part body can be axially movable with respect to sealing part support, the annular seal body comprises the substantially radially extension on the second primary seal surface that forms the axially facing of facing the first primary seal surface, and extends axially part; Wherein at least the first primary seal surface and the second primary seal surface has at least one from its axially extended annular seal tooth.

Description of drawings

Also the present invention may be better understood in conjunction with the accompanying drawings with reference to following explanation:

Fig. 1 is the schematic side view of the part of gas-turbine engine in the prior art;

Fig. 2 is the schematic sectional side view according to the face seal assembly of one embodiment of the invention structure;

Fig. 3 is the front elevation of a part of the face seal assembly spare of Fig. 2;

Fig. 4 is the amplification profile of a part of the face seal assembly of Fig. 2;

Fig. 5 is another amplification profile of a part of the face seal assembly of Fig. 2; With

Fig. 6 is the schematic sectional side view of another exemplary face seal assembly.

Embodiment

With reference to accompanying drawing, wherein identical reference character is represented components identical in all different accompanying drawings.Fig. 2 and Fig. 3 illustrate the exemplary black box 42 that leaks between sealing elevated pressures P (height) zone and lower pressure P (low) zone.In this specific examples, black box 42 has replaced aforesaid Compressor Discharge Pressure (CDP) Sealing, and be configured in central shaft 24 ' and between the diffusion chamber 12 ', yet, the feature that is appreciated that sealing assembly 42 needing can be used for any application of face seal.The basic element of character of black box 42 comprises rotor 44, fixing seals support 46 and seal body 48 (being called as " Slipper " sometimes), all is configured in around the longitudinal axis of motor.Rotor 44 is normally discoidal and form the primary seal surface 50 of first axially facing.

Seal holder 46 is the parts that extend axially that do not rotate, and forms the second right closing surface 47 of sagittal plane.In illustrated embodiment, it is one 360 ° a continuous loop, but it can be set to one section of ring structure, or a series of independent rack.Its rear end 52 has by one or more fastening pieces 56 and is fixed to the flange 54 that radially extend of diffusion on the shell 12 '.The one or more spring seats 60 of its front end 58 supportings.In this example, there are five spring seats to be equally spaced around the periphery of seal holder 46; Yet spring seat 60 replacedly is configured to loop configuration continuous or segmentation.Preferably referring to Fig. 3, spring seat 60 has generally cylindrical body 62 and forms the arcuate flanges 64 of the installation hanger 63 of a pair of horizontal expansion.This spring seat is fixed on the seal holder 46 by one or more fastening pieces 65.Shell 62 comprise the adjustment guide rail 66 that extends radially inwardly in the additional adjustment groove 68 that is installed in seal body 48 with keep desired respective corners and aim at or " aligning " of seal holder 46 and seal body 48 (clocking).Thereby so that moving axially, it does not take place laterally to move by seal holder 46 support seal bodies 48.

Seal body 48 can be the annular element of continuous or segmentation, and has L shaped section usually, and this section has radially extension 70 and extends axially part 72.

A plurality of extension springs 73 are set between the flange that extends radially outwardly 74 of spring seat 60 and seal body 48.The rear end of each extension spring 73 is arranged in spring chamber 76 or other positioning elements that is fit to of flange 74.Extension spring 73 is used for seal body 48 is removed from rotor 44, below will be described in more detail this function.As shown in the figure, five compression-type disc springs are arranged, but also can use the spring of other types and quantity.

Second Sealing 78 (as the piston ring of known type) is configured in the groove 80 of flange 74, and second sealing surfaces 47 of the axially facing of sealing and spring support assembly 46.Piston ring can be the known type seal ring with continuous (or similar continuous) circumferential seal.When allowing seal body 48 to move axially, the purpose of second sealing 78 be prevent by seal body 48 and bear and the seal holder 46 of primary seal same pressure differential between the seepage of passage.Can notice that the peculiar structure of above-mentioned Sealing and mounting structure is not restrictive, and not influence black box 42 functions for the adaptation special applications changes.

As shown in Figure 4 and Figure 5, the radially extension 70 of seal body 48 forms the second primary seal surface 82 of axially facing.This second primary seal surface 82 is in close proximity to rotor 44 and is provided with and faces the first primary seal surface 50.The circumferential sealing tooth 84 that is commonly called " rise dynamic seal " (starter seal) extends axially from the outer end of extension 70 radially in the outside of rotor 44, and in this specific examples, is radially inwardly angled.

Fluid passage

86,87 in known manner by the requirement of the hydrostatic balance in seal body 48 work by radially extension 70 formation (below be described in more detail).

The second primary seal surface 82 comprises internal plane part 82A and the exterior portion 82B that separates by circular groove 83.Exterior portion 82B comprises at least one and separate, the axially extended sealing tooth 88 of random a plurality of annulars, spaced radial, and it is to be used for flowing to secondary flow route with restriction from elementary glide path for radial fluid flow forms circuitous or crooked glide path.In illustrated embodiment, two

sealings tooth

88A and 88B have by circular bottom part groove 90 isolated tapered transverse sections.If desired, tooth 88 also can stretch out from two-dimensional surface.Can also recognize that the structure of sealing tooth can be reverse, promptly seals tooth 88 and can alternatively be formed on the first primary seal surface 50.

The structure on the second primary seal surface 82 can be divided a few part definition by the different characteristic of sealing tooth 88, comprise the number that seals tooth 88, they axial height " H ", they top width " W ", their angles " A " on cross section, they are from the divergence " S " (noticing that this angle is very little in illustrated embodiment) that axially inwardly or outwards is called as the tilt angle, their radial spacing or the total radial extension or the length of pitch " P " and the sealing tooth 88 represented with " L ".Below these sizes be exemplary, not as restriction: tooth depth H is approximately 0.38 millimeter (0.015 inch), tooth-tip angle A is approximately 10 °, tilt angle S is approximately 0 ° to 45 °, and top width W is that about 0.13 millimeter (0.005 inch) to about 0.76 millimeter (0.030 inch) and pitch P are about 1.3 millimeters (0.05 inches) to about 3.8 millimeters (0.15 inch).Can change these values for adapting to specialized application.

In illustrated embodiment, the first primary seal surface 50 has interior section 50A and at the axial exterior portion 50B of offset distance " D " (referring to Fig. 2) forward of interior section 50A, distance " D " is substantially equal to seal the axial distance of the top of tooth 88 to the interior section 82A on the second primary seal surface 82.When adopting this structure, form blocks radial flow moving " step " at the inside and outside part 50A on the first primary seal surface 50 and the junction point of 50B, and during operation, the distal part of sealing tooth 88 is axially disposed between the inside and

outside part

50A and 50B on the first primary seal surface 50.

During operation, seal body 48 combines with rotor 44 and forms sealing.Extension spring 73 supporting sealing member bodies 48 away from rotor 44 to prevent that two parts come in contact when the engine shutdown.When engine operation speed increases, hydrodynamic pressure in the primary and secondary flow passage area of motor rises, therefore and black box 42 bears acts on elevated pressure on its axial apparent surface, and its result has caused that seal body 48 moves to rotor 44.Select the relative surface area of the different piece of seal body 48 by pressing known method, the size of the quantity of

passage

86,87 and size and extension spring 73 can make black box 42 be issued to the hydrostatic pressure equilibrium of forces in selected operating conditions.Therefore, the second primary seal surface 82 never contacts the first primary seal surface 50, but with a very little axial clearance job, such as about 0.05 millimeter (0.002 inch) to about 0.13 millimeter (0.005 inch).The low running clearance of suction seal assembly 42 is in conjunction with having reduced seepage by sealing tooth 88 and the complicated flow path between first and second primary seal surface 50.

Fig. 6 illustrates another black box 142, and it comprises rotor 144, seal holder 146 and has respectively radially and the seal body 148 that extends axially part 170 and 172.Sealing assembly 142 is structurally similar with the black box of having described, but 150 different with 182 configuration aspects on first and second primary seals surfaces.Circumference plays dynamic seal 184, extends axially from the outer end of extension 170 radially.By the known method that satisfies seal body 148 hydrostatic equilibrium requirements, form fluid passages 186,187 by extension radially 170.

The second primary seal surface 182 comprises at least one and separate, the axially extended sealing tooth 188 of random a plurality of annulars, spaced radial, and it is to be used for radially forming circuitous or crooked glide path.In illustrated embodiment, three sealing

tooth

188A, 188B and 188C have the tapered transverse section that separates by circular bottom part groove 190.

For adapting to, can change the feature of the Sealing between first and second

primary seals surface

150 and 182 about the specialized application in the above-mentioned similar fashion of black box 48.

In the first primary seal surface 150, formed annular seal groove 92 with round bottom.At axial direction, corresponding sealing tooth 188C has than sealing tooth 188A and the bigger height of 188B, and extend into during operation in the seal groove 92 with further minimizing seepage.

These black boies provide the compound leakage path of labyrinth, thereby and reduce seepage than flat seal biglyyer.Yet, to compare with the existing labyrinth sealing technology of the adjacent component that may rub, the gap between the seal element can be controlled, so that the sealing tooth can the drag seal rotor.It is all providing effective seal during manufacturing of motor and between the later spreadable life.

Foreground has been described the face seal parts.Although described distinctive embodiment of the present invention, obviously, to one skilled in the art, the various improvement of carrying out all do not break away from the spirit and scope of the present invention.

Claims

1. the black box around the axis that is positioned at gas-turbine engine comprises:

Rotor (44) has the first primary seal surface (50) of axially facing;

Fixing seals support (46) is positioned near this rotor (44);

Annular seal body (48), being attached to sealing part support (46) goes up and is positioned between this rotor (44) and the sealing part support (46), sealing part body (48) can be axially movable with respect to sealing part support (46), and this annular seal body (48) comprising:

Extension radially roughly, it forms the second primary seal surface (47) in the face of the axially facing on the first primary seal surface (50), and

Roughly extend axially part (72);

Wherein, at least the first primary seal surface (50) and the second primary seal surface (82) selected one have at least one from its axially extended annular seal tooth (88).

2. black box as claimed in claim 1, wherein, described seal holder (46) forms right second sealing surfaces (47) of sagittal plane.

3. black box as claimed in claim 1, wherein, when allowing described seal body (48) when moving axially, the part that extends axially of described seal body (48) supports the second dense sealing that contacts second sealing surfaces (47).

4. black box as claimed in claim 1, wherein, one in the described at least sealing tooth (88) has the tapered transverse section.

5. black box as claimed in claim 1, wherein, another in the first and second primary seal surfaces comprises annular seal groove (80) therein, sealing groove (80) is positioned at the opposite of sealing tooth (88).

6. black box as claimed in claim 1, wherein, the second primary seal surface (47) comprising:

General flat interior section (50A); With

Exterior portion (50B), it is positioned at the radial outside of this interior section (50A) and supports described sealing tooth (88).

7. black box as claimed in claim 1, wherein, the first primary seal surface (50) has interior section (50A) and exterior portion (50B), this exterior portion in the place ahead axial dipole field of interior section (50A) so that form the moving step of blocks radial flow at the junction point of interior section (50A) and exterior section (50B).

8. black box as claimed in claim 7, wherein, the distal part of at least one in the sealing tooth (88) is positioned between the interior section (50A) and exterior portion (50B) on the first primary seal surface (50).

9. black box as claimed in claim 1 also comprises from the second primary seal surface (82) axially extended annular dynamic seal substantially.

10. black box as claimed in claim 1 also comprises at least one extension spring (73) that is positioned between seal body (48) and the seal holder (46), so that promote seal body (48) away from rotor (44).