KR20010042553A - Flex seal for gas turbine expansion joints - Google Patents

Abstract

The present invention relates to an expansion joint seal between a gas turbine exhaust duct and an axially adjacent exhaust ductline comprising a plurality of layers of axially adjacent layers of a flexible seal plate, each layer having a 360 degree annulus together. A plurality of layers of flexible seal plates, wherein the plurality of layers of flexible seal plates are secured to the gas turbine exhaust duct at one end, the opposite ends of the seal plates slidably engaging at least one surface of the exhaust duct line. do.

Description

Flexible Seal for Gas Turbine Expansion Joints {FLEX SEAL FOR GAS TURBINE EXPANSION JOINTS}

Currently used expansion joints in gas turbine exhaust systems with hot flanges are designed in one of two ways. The most common design is a flat belt device consisting of a ceramic fiber composite belt and a pedestal bag. One end of the belt is bolted to the frame attached to the gas turbine and the other end is bolted to the frame on the adjacent exhaust ductline. The gas seal in the composite belt has a Teflon® layer, metal foil or metal containing cloth. Another most common design, sometimes referred to as the "D" style, caused by the cross-sectional shape of the belt, is bolted to a bar fitted with a synthetic belt and one end mounted on a gas turbine flange and the other end bolted to a flange on the exhaust duct line. Pedestal. The belt functions as a diaphragm.

The flat belt device described first has the problem that the frame cracks due to overheating, the belt burns due to the frame crack and the back bag breakage, and leaks during the gas turbine water cleaning cycle, Damage to ceramic fiber in belt and backing bag. Liquid Fuel Combustion In the event of an ignition failure in a gas turbine, the liquid fuel inlet damages the fibers and binder and burns when the gas turbine exhaust temperature increases. In addition, when this design handles relatively large movements [in the axial direction of at least 3 inches (7.62 cm)], the stretched ceramic fibers do not return to their original form and burn and hot gas leaks.

The second described "D" style composite belt and pedestal bag mounting is not satisfactory in that it is very difficult to install this style of belt on the ductline, and over time the pedestal bag degrades and hot gases damage the belt. It causes them to break eventually.

Metal bellows mounting can be used for similar purposes, but requires two bellows separated by a few feet to accommodate transverse offset and relative axial movement. In some cases, the metal bellows concept requires high quality welding. Overall, metal bellows technology for large gas turbines is not satisfactory, as cracks due to thermal fatigue easily occur.

FIELD OF THE INVENTION The present invention relates to gas turbines and, more particularly, to flexible seal devices for expansion joints in gas turbine exhaust systems.

1 is a partial side view showing an expansion joint seal between a gas turbine duct and an adjacent exhaust duct line in accordance with a first exemplary embodiment of the present invention.

1A and 1B are enlarged detail views taken from FIG.

FIG. 2 is a partial end view of the flexible seal plate directed as shown generally in FIG. 1A.

2A-2C are end views of adjacent layers of the flexible seal plate according to the present invention.

FIG. 2D is an end view of a circumferentially divided retaining bar used to secure the flexible seal plate to the gas turbine in accordance with the present invention. FIG.

3 is a partial side view illustrating an expansion joint between a gas turbine duct and an adjacent exhaust duct line in accordance with a second exemplary embodiment of the present invention.

3A is an enlarged detail view taken from FIG. 3.

4 is an enlarged view of FIG. 3A showing the flexible seal plate in the inflated and retracted positions.

The present invention solves the problem of flexibly connecting one of the hot or cooling turbine flanges to a hot or cooling exhaust ductline flange in a component of a gas turbine axial flow exhaust system having a substantially spherical cross-sectional shape. The present invention also solves the problem in the treatment of water or liquid fuel in a manner that prevents contaminated water from leaking to the ground.

In one exemplary embodiment of the invention, the relative axial and radial movement of the hot gas turbine duct relative to the cooling exhaust ductline is received by a layer of superimposed thin metal plates, the first end of the plate being above the gas turbine duct. Bolted to a flange mounted on the other end of the plate is guided or axially supported by an adjacent exhaust ductline. The thickness and arc length of the plates are designed such that the plates seal the gas during all gas turbine operating modes. In this embodiment, the free end of the plate is flexible and coupled to the annular edge of the exhaust groove supported on the exhaust ductline and slides freely. In addition, the inherent geometry of this design allows the grooves to be incorporated into the exhaust ductline to facilitate the removal of water and liquid fuels, as described in detail below.

In a second embodiment, overlapping thin metal plates are applied for use in hot-to-hot flange devices. In this embodiment, the free edge of the flexible plate is guided in radial and transverse movements between the flanges supported by the exhaust ductline.

Insulating blankets can be used in combination with the seal plate but do not inhibit the movement of the plate in the axial, transverse or radial direction as necessary.

Accordingly, in a broader aspect, the present invention relates to a flexible seal for an expansion joint between an gas turbine exhaust duct and an axially adjacent exhaust ductline comprising a plurality of axially adjacent layers of flexible seal plates. Wherein the seal plates comprise a plurality of seal plates each having an arc length such that the seal plates form a 360 degree annular portion, wherein the plurality of layers of the flexible seal plate have opposite second ends of the seal plates at least one of the exhaust ductlines. It is coupled to the gas turbine exhaust duct at the first end while slidably coupled to the surface.

In another aspect, the present invention relates to a flexible seal for an expansion joint in a gas turbine exhaust system, the joint comprising a gas turbine duct and an adjacent exhaust ductline, the flexible seal at the first end of the gas turbine. A plurality of axially contiguous layers of annular mounting flexible seals secured to an annular mounting flange on the duct, wherein the second free ends of the flexible seal plates are slidably coupled to the exhaust duct line so that the gas turbine duct and the exhaust duct It accommodates relative axial and radial movement between lines.

Other objects and advantages of the present invention will become apparent from the following detailed description.

1, 1A and 1B show a first exemplary embodiment of the present invention, the structure of which includes a flexible seal for expansion joint between two turbine exhaust ducts 10, 12. As shown in Figure 1, the duct 10 is a gas turbine duct, while the duct 12 is an adjacent exhaust ductline extending away from the turbine. The area near the expansion joint between the ducts 10, 12 may be covered by an outer insulating blanket 14 consistent with the conventional practice (shown in phantom).

In particular in FIGS. 1A and 1B, the flexible seal for such high temperature to high temperature flange applications comprises an overlapping layer of a plurality of relatively thin flexible plates, shown generally at 16 and shown at 18. In fact, plate 18 is a three axially aligned layer of plates 18A, 18B and 18C (as shown well in FIG. 2). Each layer comprises a plurality of such plates in a peripheral alignment, each layer within a given layer being an arcuate segment that is edge adjacent to the peripheral adjacent segment as best shown in FIG. 2 and described in detail below. It consists of. Each arcuate plate 18 has a mounting flange 20 configured to engage a flange 22 formed on the front edge of the turbine duct 10, the seal plate 18 having a screw fastener (nut bolt). And a washer assembly or the like). One or more adiabatic retention flanges 26 may be secured to opposite sides of the flanges 22 as needed. Multiple restraining segments 28 function to clamp the flange 20 to the turbine flange 22, and the segments 28 are joined to form a 360 degree ring as best shown in FIGS. 2 and 2d. . The flexible seal plate 18 is bent towards the exhaust ductline 12 to engage the latter in a spring biased manner as described below.

The exhaust ductline 12 is formed with a radial mounting flange 30 to which an annular groove bracket 32 is fixed at the rearmost end. The latter extends toward the turbine duct 10 and then at 180 degree rotation 34 such that the free edge 36 of the groove bracket is joined by the flexible seal plate 18 as best shown in FIGS. 1A and 1B. Is terminated. The groove bracket 32 defines an annular radially aligned groove plate 40 that cooperates with the groove bracket 32 to form an annular exhaust groove that traps any water or fuel extending along the inner side of the turbine duct 10. A radial flange 38 is formed which engages with the flange 30 of the duct line 12. At the lowest point of the groove bracket 32 is a discharge pipe 42 which delivers the collected water and / or liquid fuel to an appropriate location.

As shown in FIGS. 1A and 1B, the flexible seal plate 18 has the free edge 36 of the groove bracket 32 in such a way that it is moved in a predetermined relative axial or radial direction between the ducts 10, 12. It will be apparent that the flexible plate 18 is spring biased to the edge 36 so that their contact is maintained in all operating states.

As already explained above, the flexible seal plates 18 are arranged in multiple overlapping layers near the periphery of the duct joint. The thickness and arc length of the plate 18 are designed to seal the gas in all gas turbine operating modes. This configuration forms a compact metal "diaphragm" capable of relatively large axial and radial movements, which in turn enables efficient space use.

The layer arrangement of the plate 18 is best shown in FIG. In particular, plate 18 is secured to turbine duct flange 22 having a first layer of inconel® plate 18A having a thickness of about 0.1016 cm (0.040 inch). The first layer comprises 28 plates with three holes and one plate 18 'with two holes in this exemplary embodiment. In other words, in more detail, the circumferential extent of each plate is determined at least in part by a plurality of holes in the plate that mate with evenly spaced holes in the turbine duct flange 22.

The second layer of Inconel® plate 18B having a thickness of about 0.0508 cm (0.020 inch) includes 28 plates 28 with three holes and one plate with two holes, but The plates of the two layers are moved in a circumferential direction so as to overlap between the first and second layers in the radial seam of the plates in each layer. The third layer of Inconel® plate 18C having a thickness of about 0.1016 cm (0.040 inch) includes 28 plates 28 with three holes and one plate with two holes. The third layer is substantially circumferentially aligned with the first layer to overlap between the radial seams between the second and third layers. However, the first and third layers need not be precisely aligned and can be offset by, for example, one mounting hole. The fourth layer consists of a containment bar assembly 28 and has a configuration similar to a turbine duct radial flange such that a third layer of flexible plate is interposed between the containment bar 28 and the turbine duct flange 22. The containment bar is provided in the form of a circumferential segment and in an exemplary embodiment comprises eight bars 10 with ten holes and one bar 6 with six holes. Each suppression bar segment preferably has an arc length of at least three times the arc length of the individual plate 18. Tabs may be welded to one end of each segment to cover the seam between the segments.

It can be seen that the number of mounting holes 44 on the turbine duct flange 10 and their spacing depends on the arc length and number of plates 18 (and restraining segments) for each layer. If by way of example, twenty-five plates with three holes with the same arc length can be used if the number of holes can be divided into three (eg 75 holes). However, in the illustrated embodiment, there are 86 holes in the turbine duct and exhaust ductline flanges, so one plate requires two more than three holes and a smaller arc length than the remaining plates in the layer. .

3, 3A and 4 show a second embodiment of the present invention, in particular, this embodiment is particularly applicable to hot-cold flange applications. In this arrangement, the flexible plate 118 (arranged in layers as described previously) is mounted radially on the turbine duct 110 to be radially coupled to the guide means provided on the exhaust ductline 112. Extend outwards. In particular, the radially outer end 120 of the plate 118 is a gas turbine by means of a fastening piece 124 and a suppression bar assembly 128 similar to the mounting device described in connection with the embodiment shown in FIGS. 1 and 2. It is mounted on the radial flange 122 of the duct 110. At the same time, the radially inner free ends of the flexible plate 118 can be moved radially in all directions inward and outward and can guide radially extending flanges. In particular, the end of the plate 118 defines a freely moving radial slot, rather than the way the flexible seal plate is guided in the radial direction. The flanges 130 and 132 are fixed to the exhaust groove 134 by the fastening piece 136. As a result, as in the particular example in FIG. 4, the flexible plate 118 can accommodate movement in both axial and radial directions, and when the plate 118 is cooled, the leftmost as shown in FIG. 4. It can be seen that the position and the rightmost position when heat treated. The axial movement is accompanied by radial movement and is received by the sliding relationship between the flanges 130, 132 and the free end of the plate 118.

In the second embodiment, the exhaust grooves 134 are formed by the annular walls 138 and 140 spaced apart in the axial direction and the plate 118 itself to guide water and / or fuel along the inside of the turbine duct 10. Capture it. In addition, the exhaust pipe 142 is provided similarly to the pipe 42. An insulating blanket may be included in the space between the walls of the exhaust ductline including the area surrounding the exhaust pipe 142.

As described above, the present invention provides reliability and long life. In this regard, the lifetime of the metal seal plate can be easily calculated using a typical guide calculation. In addition, the seal according to the invention accommodates more relative movement between adjacent ducts, i.e., more than 7.62 cm (3 inches), than the prior art.

While the invention has been described in connection with more practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments but includes various modifications and corresponding apparatus within the spirit and scope of the appended claims.

Claims (11)

A flexible seal for an expansion joint between an axial adjacent exhaust ductline comprising a gas turbine exhaust duct and a plurality of axially adjacent layers of flexible seal plates, each layer having a 360 degree annulus therein. A plurality of seal plates each having an arc length to form a plurality of seal plates, wherein the plurality of layers of flexible seal plates are formed with the second opposite end of the seal plate slidably coupled to at least one surface of the exhaust ductline. A flexible seal for an expansion joint, coupled to a gas turbine exhaust duct at one end. The flexible seal of claim 1 wherein at least one surface of the exhaust ductline comprises an edge of the annular exhaust groove. The flange of claim 1, wherein at least one surface of the exhaust ductline has a plurality of axially spaced and circumferentially arranged flanges therebetween forming annular radial grooves between which the opposite ends of the seal plate are slidably received. Flexible seal for expansion joint comprising a. 2. The flexible seal of claim 1 wherein the plurality of layers comprise three layers. 3. The flexible seal of claim 2 wherein the exhaust groove comprises an annular, partially donut shaped member having an exhaust pipe at the bottom. 2. The flexible seal of claim 1 wherein the flexible seal plates of each layer are circumferentially offset from the flexible seal plates of adjacent layers. 10. The flexible seal of claim 1 comprising a containment bar assembly having a plurality of containment bar segments for clamping the flexible seal plate against a radial flange on the gas turbine exhaust duct. 8. The flexible seal of claim 7 wherein at least one surface of the exhaust ductline comprises an edge of the annular exhaust groove. 8. The flange of claim 7, wherein at least one surface of the exhaust ductline has a plurality of axially spaced and peripherally arranged flanges therebetween defining annular radial grooves therebetween for sliding the opposing ends of the seal plates. Flexible seal for expansion joint comprising a. 2. The flexible seal of claim 1 wherein the turbine exhaust duct and the exhaust duct line are circular in cross section and the turbine exhaust duct has a smaller diameter than the exhaust duct line. A flexible seal for an expansion joint in a gas turbine exhaust system, the joint comprising a gas turbine duct and an adjacent exhaust ductline, wherein the flexible seal has a second free end of the flexible seal plate for the gas turbine duct and the exhaust ductline. Multiple axes of annularly arranged flexible seals fixed to an annular mounting flange on the gas turbine duct at the first end, slidably coupled to the exhaust ductline to accommodate relative axial and radial movement therebetween. A flexible seal for an expansion joint, comprising a directionally adjacent layer.