Outflow housing of a steam turbine

Abstract

An outflow housing for a turbine section of a steam turbine. The outflow housing has an outflow housing wall, which surrounds a central drum chamber along a housing longitudinal axis, and a connection interface for connecting the outflow housing to a turbine housing of the steam turbine. A sealing device for sealing an end of the outflow housing, which end is arranged at the rear in the flow direction, with respect to a turbine shaft of the steam turbine is arranged on the outflow housing wall, wherein the sealing device is sealed to the outflow housing wall. A steam turbine has the outflow housing herein.

Claims

1. An outflow housing for a turbine section of a steam turbine, comprising: an outflow housing wall, which surrounds a central drum chamber along a housing longitudinal axis, and an attachment interface for attachment of the outflow housing to a turbine housing of the steam turbine, and a sealing device arranged on the outflow housing wall for sealing off a rear end, as viewed in a flow direction, of the outflow housing with respect to a turbine shaft of the steam turbine, wherein the sealing device is sealed off with respect to the outflow housing wall, wherein the outflow housing wall has at least one outflow channel which at least partially surrounds the housing longitudinal axis, and wherein at least one outflow connector is arranged for fluid communication on the outflow channel, the at least one outflow connector extends transversely with respect to the housing longitudinal axis and is designed for conducting steam away from the turbine housing.

2. The outflow housing as claimed in claim 1, wherein the outflow housing wall has a receiving device for receiving the sealing device.

3. The outflow housing as claimed in claim 1, wherein the sealing device is arranged on the outflow housing wall at a side, facing toward the housing longitudinal axis, of the at least one outflow channel and adjacent to the outflow channel.

4. The outflow housing as claimed in claim 1, wherein the attachment interface is formed on an outer side, averted from the central drum chamber, of the outflow housing wall.

5. The outflow housing as claimed in claim 4, wherein no attachment interface is formed on the outflow housing adjacent to the sealing device in a radial direction.

6. The outflow housing as claimed in claim 4, wherein the attachment interface surrounds or at least substantially surrounds the housing longitudinal axis.

7. The outflow housing as claimed in claim 1, wherein an inner side, facing toward the drum chamber, of the outflow housing wall has at least one guide blade ring.

8. A steam turbine, comprising: a first turbine section, a second turbine section and a turbine housing which surrounds the first turbine section and the second turbine section, wherein the first turbine section is coupled for fluid communication to the second turbine section via a reheating device, and an outflow housing as claimed in claim 1 arranged within the turbine housing at a rear end region, in the flow direction of the steam turbine, of the first turbine section.

9. The steam turbine as claimed in claim 8, wherein the outflow housing is arranged on the steam turbine such that a steam mass flow flowing through the central drum chamber impinges on the turbine housing only after flowing through the reheating device positioned downstream of the outflow housing.

10. The steam turbine as claimed in claim 8, wherein the outflow housing is held on the turbine housing by the attachment interface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An outflow housing according to the invention and a steam turbine according to the invention will be discussed in more detail below on the basis of drawings, in which, in each case schematically:

(2) FIG. 1 shows a steam turbine according to the prior art in a side view,

(3) FIG. 2 shows a detail of a steam turbine according to the invention, with a lower part of an outflow housing according to the invention, in a plan view, and

(4) FIG. 3 shows an upper part of an outflow housing according to the invention in a perspective view.

DETAILED DESCRIPTION OF INVENTION

(5) FIG. 1 illustrates a steam turbine (3) according to the prior art schematically in a side view. The steam turbine 3 has multiple turbine sections 2, which are designed for example as high-pressure turbine stage, medium-pressure turbine stage and low-pressure turbine stage. In each case one guide blade carrier 20 with multiple guide blade rings 14 is arranged in the turbine sections 2. A central turbine section 2 is delimited in a flow direction S by a sealing shell 21. The sealing shell 21 prevents an onward flow of a steam mass flow in the flow direction S, and diverts said steam mass flow in the direction of the turbine housing 8 and further into an extraction device. An outlet is coupled for fluid communication to a downstream turbine section 2.

(6) This steam turbine 3 according to the prior art has the disadvantage that, during operation, the steam mass flow that is diverted by the sealing shell 21 and which is at a relatively low temperature flows against the turbine housing 8, wherein relatively hot steam mass flows flow against the turbine housing 8 adjacently upstream and adjacently downstream in the flow direction. The turbine housing is accordingly exposed initially to a steam mass flow at a relatively high temperature, subsequently to a steam mass flow at a relatively low temperature, and finally to a steam mass flow at a relatively high temperature. This gives rise to a large temperature gradient in the turbine housing 8, which places a high load on the steam turbine 3 and limits a maximum power of the steam turbine 3.

(7) FIG. 2 schematically shows a detail of a steam turbine 3 according to the invention in a plan view. The steam turbine 3 has a turbine housing 8, of which only a housing lower part 8a is illustrated in this view. The turbine housing 8 extends along a housing longitudinal axis 6, surrounds the housing longitudinal axis 6 over a full circumference, and thus surrounds or delimits a flow chamber 16 for the throughflow of a steam mass flow. The steam turbine 3 has a multiplicity of turbine sections. An outflow housing 1 according to the invention is arranged in a rear end region 15, in the flow direction S, of a first turbine section 2a, which is adjacent to a second turbine section 2b.

(8) The outflow housing 1 has an outflow housing wall 4, which extends along the housing longitudinal axis 6 and which surrounds the housing longitudinal axis 6 over a full circumference and which thus surrounds or delimits a central drum chamber 5 in a radial direction. Guide blade rings 14 (cf. FIG. 1) are arranged in the drum chamber 5, which guide blade rings are not illustrated in this view. An encircling attachment interface 7 is formed on an outer side, averted from the drum chamber 5, of the outflow housing wall 4. The attachment interface is, in this example, formed as an encircling flange which extends radially outward from the outflow housing wall 4. The outflow housing 1 is held or fixed by means of the attachment interface 7 on the turbine housing 8, for example by means of a screw connection. For this purpose, the turbine housing 8 has a corresponding holding device 17.

(9) The outflow housing 1 has, in the flow direction S, a rear end 10 in which a receiving device 11 for receiving a seal device 9 is arranged. The seal device 9 is designed for sealing off the outflow housing 1 with respect to a turbine shaft (not illustrated). At the rear end 10 of the outflow housing 1, there is formed an outflow channel 12 which surrounds the housing longitudinal axis 6. A steam mass flow flowing through the drum chamber 5 is thus prevented from flowing onward in the flow direction S, and is conducted into the outflow channel 12, by the seal device 9.

(10) FIG. 3 schematically shows, in a perspective illustration, an upper part 1b of the outflow housing 1 according to the invention from FIG. 2. Like the lower part 1a, the upper part 1b extends along the housing longitudinal axis 6, and surrounds the housing longitudinal axis 6 over 180°. By means of a connecting flange 18, the upper part 1b can be screwed together with the lower part 1a. The outflow channel 12 likewise extends in the circumferential direction over the upper part 1b, wherein the outflow channel 12 has, at two points, outwardly pointing openings at which there is arranged in each case one outflow connector 13, which outflow connectors extend approximately in a tangential direction from the outflow channel 12. Via the outflow connectors 13, the steam mass flow can be conducted out of the outflow housing 1 and fed into the reheating device (not illustrated), without the steam mass flow impinging on the turbine housing 8.