JP2006104962A - Exhaust expansion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust expansion for contributing to improving reliability of a gas turbine, by not only absorbing the thermal expansion of an exhaust cabin and an exhaust duct by a temperature change in exhaust gas but also insulating vibration between the exhaust cabin and the exhaust duct, with a simple constitution. <P>SOLUTION: A plate spring 3 for connecting these is arranged between the exhaust cabin 1 and the exhaust duct 2 of the gas turbine. The plate spring 3 extends further to the downstream side from an exhaust gas downstream side end part on an outer peripheral surface of the exhaust cabin 1. A tip part of the plate spring 3 abuts on an upstream side surface of a flange 2a arranged in a ring shape over the whole periphery in an exhaust gas upstream side end part on an pouter peripheral surface of the exhaust duct 2, and the plate spring 3 is put in a state of warping to the turbine outer peripheral side. In this state, the thermal expansion and vibration in the turbine shaft direction indicated by an arrow B in the exhaust cabin 1 and the exhaust duct 2, are absorbed by elastic deformation of the plate spring 3. Vibration in the turbine radial direction indicated by an arrow C is absorbed by sliding of the plate spring 3 and the flange 2a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust expansion that connects an exhaust casing of a gas turbine and an exhaust duct.

  Conventionally, in a gas turbine, an exhaust expansion that connects the exhaust casing and an exhaust duct has been used. Such exhaust expansion includes the following configurations.

  For example, in an exhaust expansion of a gas turbine that is connected between a gas turbine exhaust port and an exhaust duct via a flange and the outer periphery of the flange is hermetically covered with a bellows, an annular space is formed with the bellows. As described above, Patent Document 1 discloses a configuration in which the bellows is provided with a supply unit for supplying a refrigerant from outside and a discharge unit for discharging the refrigerant to the outside.

  As a result, the bellows is cooled by the refrigerant supplied to the annular space inside the bellows, and the thermal degradation of the bellows over time is suppressed, so that the airtightness of the exhaust gas is maintained over a long period of time and the reliability of the power supply It is said that an exhaust expansion of the gas turbine that can maintain the above can be obtained.

  In addition, the front duct and the rear duct for guiding the exhaust gas of the gas turbine are connected, and both ducts gradually enlarge the cross section from the inlet side toward the outlet side, and the connecting part of both the ducts is the both ducts. In the exhaust gas duct connection structure in which the frames having opposite surfaces are attached to the outer periphery of the end portions, and a stretchable member is attached between the opposite surfaces of the frames, the frames and the frames A support member that connects between the outer periphery of each duct to which the frame is attached, and one end fixed to the outside of each of the ducts, and the other end in a direction in which the periphery of the front end of each frame pulls the stretchable member The thing of the structure which provided the stopper which prevents inclining is disclosed by patent document 2. FIG.

Such a structure prevents the frame from being excessively tilted or drooped by the support member, and the stopper prevents the frame from pulling and retracting the stretchable member, thereby damaging the stretchable member. In addition to preventing this, it is also possible to prevent weld cracks in the frame mounting portion.
JP 2000-303857 A JP-A-11-350976

  However, in the conventional configuration as described above, although the thermal expansion and contraction of the exhaust casing and the exhaust duct due to the temperature change of the exhaust gas can be absorbed or suppressed, the vibration is insulated between the exhaust casing and the exhaust duct. I couldn't.

  In view of such problems, the present invention has a simple configuration and not only absorbs thermal expansion and contraction of the exhaust casing and the exhaust duct due to temperature changes of the exhaust gas, but also vibrates between the exhaust casing and the exhaust duct. An object of the present invention is to provide an exhaust expansion that contributes to improving the reliability of a gas turbine.

  In order to achieve the above object, according to the present invention, in an exhaust expansion formed by connecting an exhaust casing that guides exhaust gas of a gas turbine and an exhaust duct, from the exhaust gas downstream end of the exhaust casing further downstream. Exhaust expansion in which a leaf spring is provided, and the leaf spring contacts a flange provided at an exhaust gas upstream end of the exhaust duct, and thermal expansion and contraction and vibration in the turbine axial direction in the exhaust casing and the exhaust duct Is absorbed by elastic deformation of the leaf spring, and vibration in the radial direction of the turbine is absorbed by the slide of the leaf spring and the flange.

  Further, a bellows is provided between the exhaust casing and the leaf spring, and thermal expansion and contraction and vibration in the turbine axial direction are further absorbed by elastic deformation of the bellows.

  Alternatively, in an exhaust expansion formed by connecting an exhaust casing for guiding exhaust gas of a gas turbine and an exhaust duct, the exhaust gas downstream end of the exhaust casing is thinned and provided at the exhaust upstream end of the exhaust duct. Exhaust expansion in which the exhaust gas downstream side end of the exhaust casing comes into contact with the conical portion, and thermal expansion and contraction and vibration in the turbine axial direction and vibration in the turbine radial direction in the exhaust casing and the exhaust duct, The exhaust gas chamber is absorbed by the elastic deformation of the exhaust gas downstream end of the exhaust casing and the slide of the exhaust gas downstream end of the exhaust casing and the conical portion.

  Alternatively, in an exhaust expansion formed by connecting an exhaust casing for guiding exhaust gas of a gas turbine and an exhaust duct, a bellows and a leaf spring extending further downstream from the bellows are provided at the exhaust gas downstream end of the exhaust casing. An exhaust expansion in which the leaf spring comes into contact with a conical portion provided at an exhaust gas upstream end portion of the exhaust duct, and thermal expansion and contraction and vibration in a turbine axial direction in the exhaust casing and the exhaust duct, and The vibration in the radial direction of the turbine is absorbed by elastic deformation of the bellows and the leaf spring and sliding between the leaf spring and the conical portion.

  Alternatively, in an exhaust expansion formed by connecting an exhaust casing for guiding exhaust gas of a gas turbine and an exhaust duct, a seal air that flows from the inner peripheral surface of the exhaust casing to the inner peripheral surface of the exhaust duct is provided, and the seal air The exhaust gas is sealed from outside between the exhaust casing and the exhaust duct so as not to leak outside.

  In addition, a first seal sleeve that extends further downstream from the exhaust gas downstream end of the exhaust casing and a second seal sleeve that extends further upstream from the exhaust upstream end of the exhaust duct are provided. In the first and second seal sleeves, one outer peripheral surface and the other inner peripheral surface are made to face each other at a predetermined interval.

  Furthermore, a brush seal extending from one seal sleeve to the other seal sleeve of the first and second seal sleeves is provided.

  According to the present invention, with a simple configuration, not only the thermal expansion and contraction of the exhaust casing and the exhaust duct due to the temperature change of the exhaust gas is absorbed, but also the vibration is insulated between the exhaust casing and the exhaust duct, It is possible to provide an exhaust expansion that contributes to the improvement of the reliability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view schematically showing the configuration of an exhaust expansion according to Embodiment 1 of the present invention, and shows only one outer peripheral portion cut in parallel with the center line (the same applies to the following embodiments). . In the figure, a leaf spring 3 is provided between an exhaust casing 1 and an exhaust duct 2 of the gas turbine to connect them. The exhaust gas from the gas turbine flows from the exhaust casing 1 to the exhaust duct 2 as indicated by an arrow A.

  The leaf spring 3 extends further downstream from the exhaust gas downstream end on the outer peripheral surface of the exhaust casing 1. And the front-end | tip part of the leaf | plate spring 3 contact | abuts to the upstream side surface of the flange 2a provided in the ring shape over the perimeter on the exhaust gas upstream side edge part in the outer peripheral surface of the exhaust duct 2, and the leaf | plate spring 3 is a turbine outer periphery. It is in a state of warping to the side. In this state, the thermal expansion and contraction and vibration in the turbine axial direction indicated by the arrow B in the exhaust casing 1 and the exhaust duct 2 are absorbed by elastic deformation of the leaf spring 3, and the vibration in the turbine radial direction indicated by the arrow C is absorbed. The structure is such that it is absorbed by sliding between the leaf spring 3 and the flange 2a.

  A substantially cylindrical flow sleeve 4 extends from the exhaust gas downstream end to the downstream side on the inner peripheral surface of the exhaust casing 1 over the entire circumference. It does not directly flow into the gap with the exhaust duct 2 but serves to guide the exhaust duct 1 to flow smoothly from the exhaust casing 1 to the exhaust duct 2.

  FIG. 2 is a schematic view of the exhaust expansion viewed from the outer peripheral side. The leaf spring 3 is provided on the outer peripheral surface of the exhaust casing 1 over the entire circumference. As shown in FIG. 5A, this is from the downstream end toward the upstream side with respect to the substantially cylindrical member. If the slits 3a that are opened are arranged at predetermined intervals in the turbine circumferential direction, or the long plate-like members 3b are overlapped in the turbine circumferential direction as shown in FIG. good. As a result, the leaf spring 3 extends radially around the exhaust casing 1 with the exhaust casing 1 and the exhaust duct 2 connected.

  However, the configuration shown in FIG. 5B has better sealing performance between the exhaust casing 1 and the exhaust duct 2 than the configuration shown in FIG. It should be noted that the present invention is not limited to the configurations shown in (a) and (b) of the figure, and may be a combination of these, for example. The material of the leaf spring 3 is preferably heat resistant spring steel or stainless steel.

  FIG. 3 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to the second embodiment of the present invention. In the present embodiment, in addition to the configuration of the first embodiment, a bellows is provided. That is, as shown in the figure, a substantially annular bellows 5 extending from the exhaust gas downstream end to the downstream side is provided on the outer peripheral surface of the exhaust casing 1, and the above-described leaf spring 3 is provided at the exhaust gas downstream end. It is set as the structure provided with. Thereby, the thermal expansion and contraction and vibration in the turbine axial direction in the exhaust casing 1 and the exhaust duct 2 are further absorbed by the elastic deformation of the bellows 5. As a result, the amount of bending of the leaf spring 3 can be reduced, and the design can be provided with a margin.

  FIG. 4 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to Embodiment 3 of the present invention. In the present embodiment, a taper portion 1 a is provided on the inner peripheral surface of the exhaust casing 1 at the exhaust gas downstream side end so that the inner diameter of the exhaust casing 1 increases toward the downstream side. The end is thin and springy. As in the configuration shown in FIG. 2A, the slits opened from the downstream end of the exhaust casing 1 toward the upstream side are arranged at predetermined intervals in the turbine circumferential direction. A function similar to that of the leaf spring is provided.

  On the other hand, the exhaust gas upstream side end of the exhaust duct 2 is provided with a conical portion 2b that opens in a substantially conical shape so that the diameter of the exhaust duct 2 increases toward the upstream side. Then, the exhaust gas downstream side end of the exhaust casing 1 is inserted into the open portion, and the exhaust gas downstream end of the exhaust casing 1 is brought into contact with the inner peripheral surface of the conical portion 2b. And the exhaust duct 2 are connected. In this case, in the exhaust casing 1 and the exhaust duct 2, the thermal expansion and contraction and vibration in the turbine axis direction indicated by the arrow B and the vibration in the turbine radial direction indicated by the arrow C are caused by elastic deformation of the downstream end portion of the exhaust casing 1. And the exhaust casing 1 downstream side end and the conical portion 2b inner peripheral surface of the exhaust duct 2 are absorbed by the slide.

  Instead of the tapered portion 1a, a tapered portion is provided on the outer peripheral surface of the exhaust casing 1 at the exhaust gas downstream end so that the inner diameter of the exhaust casing 1 becomes smaller toward the downstream side. It is good also as a structure which makes a downstream end part thin. Alternatively, instead of providing the tapered portion, the inner circumferential surface or the outer circumferential surface of the exhaust casing 1 may be deleted to provide a substantially cylindrical thin portion. In addition to the above configuration, as shown in FIG. 4, the substantially cylindrical flow described above over the entire periphery from the exhaust gas downstream end to the downstream side on the inner peripheral surface of the exhaust casing 1. The sleeve 4 may be extended.

  FIG. 5 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to Embodiment 4 of the present invention. In the present embodiment, the configuration provided with the bellows in the second embodiment and the configuration provided with the conical portion 2b in the third embodiment are combined. That is, as shown in the figure, the exhaust casing 1 is provided with a substantially annular bellows 5 extending from the exhaust gas downstream end to the downstream side on the outer peripheral surface thereof, and the exhaust gas downstream end is described above. On the other hand, the exhaust gas upstream end portion of the exhaust duct 2 is provided with a conical portion 2b that opens in a substantially conical shape so that the diameter of the exhaust duct 2 increases toward the upstream side. Yes. Then, the leaf spring 3 is inserted into the open portion, the tip of the leaf spring 3 is brought into contact with the inner peripheral surface of the conical portion 2b, and the exhaust casing 1 and the exhaust duct 2 are connected.

  In this case, in the exhaust casing 1 and the exhaust duct 2, the thermal expansion and contraction and vibration in the turbine axis direction indicated by the arrow B and the vibration in the turbine radial direction indicated by the arrow C are caused by elastic deformation of the bellows 5 and the leaf spring 3. And it is set as the structure absorbed by the slide of the front-end | tip part of the leaf | plate spring 3, and the said conical part 2b of the exhaust duct 2. As shown in FIG. In addition to the above configuration, as shown in the figure, the substantially cylindrical flow described above over the entire circumference from the exhaust gas downstream end to the downstream on the inner peripheral surface of the exhaust casing 1. The sleeve 4 may be extended.

  FIG. 6 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to Embodiment 5 of the present invention. In the present embodiment, a plurality of air supply pipes 6 are provided at predetermined intervals along the circumferential direction around the downstream end of the exhaust casing 1. The seal air is supplied from the air supply pipe 6 into the exhaust casing 1. On the other hand, a ring 7 that forms a predetermined gap with the inner peripheral surface of the exhaust casing 1 is provided inside the exhaust casing 1 where the air supply pipe 6 is provided. The annular ring 7 is provided with a flange-shaped part 7 a at the outer peripheral edge of the exhaust gas upstream side end, which is connected to the inner peripheral surface of the exhaust casing 1 and upstream of the gap between the exhaust casing 1 and the ring 7. It is attached to the exhaust casing 1 with the side end closed.

  The seal air supplied from the air supply pipe 6 into the exhaust casing 1 as indicated by an arrow D passes between the inner peripheral surface of the exhaust casing 1 and the outer peripheral surface of the ring 7 and passes through the exhaust casing 1. And from each downstream end of the ring 7, as shown by an arrow E, it is ejected in the exhaust gas downstream direction. The ejected seal air is introduced into the exhaust duct 2 along its inner peripheral surface. That is, the seal air flows from the inner peripheral surface of the exhaust casing 1 to the inner peripheral surface of the exhaust duct 2. Thereby, an air curtain is formed between the exhaust casing 1 and the exhaust duct 2, and the exhaust casing 1 and the exhaust duct 2 are connected in a non-contact manner while sealing so that the exhaust gas does not leak to the outside.

  By the way, as a supply source of the seal air, for example, extraction from a compressor of a gas turbine may be performed, or a compressor may be provided separately. Moreover, in order to ensure sealing performance, it is necessary to eject seal air at a higher speed than the main stream of exhaust gas. On the other hand, in order to maintain the efficiency of, for example, a boiler (not shown) that is disposed downstream of the exhaust duct and is supplied with exhaust gas, the temperature of the seal air to be supplied should be equal to the exhaust gas temperature. In addition, even when the exhaust duct 2 is located on the innermost side with respect to the exhaust casing 1 due to the vibration, it is necessary that the sealing air be in an arrangement relationship in which the seal air is reliably introduced into the exhaust duct 2.

  The exhaust gas downstream end of the ring 7 is aligned with the exhaust gas downstream end of the exhaust casing 1 with respect to the exhaust gas flow direction, so that the seal air from here is ejected almost straight in the exhaust gas flow direction. Therefore, it becomes possible to seal efficiently. In addition, a tapered portion 2c is provided on the inner peripheral surface of the exhaust duct 2 at the exhaust gas upstream end so that the inner diameter of the exhaust duct 2 increases toward the upstream side. It is designed to be easily introduced into the duct 2. In addition to the above configuration, as shown in the figure, the substantially cylindrical flow sleeve 4 described above is provided over the entire circumference from the exhaust gas upstream end to the downstream on the inner circumferential surface of the ring 7. It may be extended. This is the same in the following embodiments.

  FIG. 7 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to Embodiment 6 of the present invention. In the present embodiment, in addition to the configuration of the fifth embodiment, as shown in the figure, a substantially annular seal that extends further from the outer peripheral surface of the exhaust gas downstream end of the exhaust casing 1 further downstream. A sleeve 8 and a substantially annular seal sleeve 9 extending from the outer peripheral surface of the exhaust gas upstream end of the exhaust duct 2 to the upstream side over the entire circumference are provided.

  Then, by causing the outer peripheral surface of the seal sleeve 8 and the inner peripheral surface of the seal sleeve 9 to face each other at a predetermined interval, a pressure loss is generated in this portion, and a differential pressure between the inside and the outside of the gas turbine is earned, thereby exhaust gas. Is made difficult to leak from between the exhaust casing 1 and the exhaust duct 2 to the outside, and the sealing performance by the seal air is improved. As a result, the supply amount of seal air can be relatively reduced. In addition, as for the surface which the seal sleeves 8 and 9 oppose, an outer peripheral surface and an inner peripheral surface may be reverse to the same figure. Further, the predetermined interval between the outer peripheral surface and the inner peripheral surface facing each other is arbitrarily determined according to a required differential pressure value.

  FIG. 8 is a partial cross-sectional view schematically showing the configuration of the exhaust expansion according to Embodiment 7 of the present invention. In the present embodiment, in addition to the configuration of the sixth embodiment, a brush seal 10 is provided between the seal sleeves 8 and 9 as shown in FIG. The brush seal 10 is made of, for example, a metal brush, and extends from one seal sleeve to the other seal sleeve over the entire circumference. Thereby, it is set as the structure which further improves the sealing performance by sealing air by producing a big pressure loss by this part and earning more differential pressure of the inside and outside of a gas turbine. It should be noted that any number of brush seals 10 may be provided in the exhaust gas flow direction according to the required differential pressure value.

  The configuration of the present invention is not limited to a gas turbine, but can be applied to all exhaust duct connection portions.

1 is a partial cross-sectional view showing a configuration of an exhaust expansion according to Embodiment 1 of the present invention. The schematic diagram which looked at the exhaust expansion of Example 1 from the outer peripheral side. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 2 of this invention. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 3 of this invention. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 4 of this invention. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 5 of this invention. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 6 of this invention. The fragmentary sectional view which shows the structure of the exhaust expansion which concerns on Example 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust compartment 2 Exhaust duct 3 Leaf spring 4 Flow sleeve 5 Bellows 6 Air supply pipe 7 Ring 8,9 seal sleeve 10 Brush seal

Claims (7)

In the exhaust expansion that connects the exhaust casing that leads the exhaust gas of the gas turbine and the exhaust duct,
An exhaust expansion in which a leaf spring extending further downstream from the exhaust gas downstream end of the exhaust casing is provided, and the leaf spring abuts on a flange provided at the exhaust gas upstream end of the exhaust duct,
In the exhaust casing and the exhaust duct, thermal expansion and contraction and vibration in the turbine axial direction are absorbed by elastic deformation of the leaf spring, and vibration in the turbine radial direction is absorbed by sliding between the leaf spring and the flange. Exhaust expansion characterized by that.   The exhaust expansion according to claim 1, wherein a bellows is provided between the exhaust casing and the leaf spring to further absorb thermal expansion and contraction and vibration in the turbine axial direction by elastic deformation of the bellows. . In the exhaust expansion that connects the exhaust casing that leads the exhaust gas of the gas turbine and the exhaust duct,
An exhaust expansion in which the exhaust gas downstream side end of the exhaust casing is thinned, and the exhaust gas downstream end of the exhaust casing abuts on a conical portion provided at the exhaust gas upstream end of the exhaust duct,
In the exhaust casing and the exhaust duct, thermal expansion and contraction and vibration in the turbine axial direction and vibration in the turbine radial direction are caused by elastic deformation of the exhaust gas downstream side end of the exhaust casing and exhaust gas downstream side of the exhaust casing. An exhaust expansion which is absorbed by a slide between an end portion and the conical portion. In the exhaust expansion that connects the exhaust casing that leads the exhaust gas of the gas turbine and the exhaust duct,
A bellows and a leaf spring extending further downstream from the bellows are provided at the exhaust gas downstream end of the exhaust casing, and the leaf spring contacts the conical portion provided at the exhaust gas upstream end of the exhaust duct. Exhaust expansion,
The thermal expansion and contraction and vibration in the turbine axial direction and the vibration in the turbine radial direction in the exhaust casing and the exhaust duct are absorbed by elastic deformation of the bellows and the leaf spring, and sliding between the leaf spring and the conical portion. Exhaust expansion characterized by that. In the exhaust expansion that connects the exhaust casing that leads the exhaust gas of the gas turbine and the exhaust duct,
Seal air that flows from the inner peripheral surface of the exhaust casing to the inner peripheral surface of the exhaust duct is provided, and the exhaust air is sealed from the gap between the exhaust casing and the exhaust duct by the seal air. Exhaust expansion characterized by that.   A first seal sleeve extending further downstream from the exhaust gas downstream end of the exhaust casing, and a second seal sleeve extending further upstream from the exhaust gas upstream end of the exhaust duct, 6. The exhaust expansion according to claim 5, wherein, of the first and second seal sleeves, one outer peripheral surface and the other inner peripheral surface are opposed to each other at a predetermined interval.   The exhaust expansion according to claim 6, further comprising a brush seal extending from one of the first and second seal sleeves to the other seal sleeve.

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