1. A steam turbine installation comprising low pressure turbine means having a rotor mounted on a shaft and surrounded by a cylindrical turbine housing concentric with the shaft, at least one bearing supporting the shaft, a pressure tight outer housing surrounding the turbine housing and concentric with the shaft, the outer housing having continuous walls supporting the bearing, an external foundation supporting the outer housing, formed in the annulus between the turbine housing and the outer housing in respective arcuate segments of the annulus on each side of the turbine a respective condenser section comprising a plurality of condenser tubes means adjacent the condenser tubes for exhausting steam from the turbine directly into contact with the condenser tubes, and the outer housing having a removable segment of a generally V-shaped cross-sectional configuration with the apex of the V being disposed closest to the rotor shaft, the segment extending along the axial length of the outer housing, having V-shaped walls at its ends and being at least as wide as the turbine housing diameter.
2. A steam turbine installation according to claim 1 further comprising low-pressure preheaters disposed within said outer housing below said turbine means.
3. A steam turbine installation according to claim 2 wherein said turbine means drives a generator, said preheaters being constructed and arranged to be pulled out longitudinally underneath said generator.
4. A steam turbine installation according to claim 1 wherein auxiliary inlet lines pass through one of the end walls of said removable segment.
5. A steam turbine installation according to claim 1 wherein said condenser sections have inlet and outlet lines for cooling water, said lines passing through at least one of the end walls of said housing.
6. A steam turbine installation according to claim 1 wherein said turbine means comprises two low-pressure turbines, the bearing is disposed between said two turbines, and the outer housing is provided with wall means defining an access passage for said bearing.
7. A steam turbine installation according to claim 1 wherein said outer housing is supported externally by mounting means on the sides thereof.
8. A steam turbine installation according to claim 1 wherein said housing has an upper and a lower space between said two condenser sections, said upper space being occupied by said removable segment and said lower space being occupied by heaters.
In steam turbine installations, it is customary to arrange the condenser for the steam which passes from the low-pressure turbine below the latter. However, the massiveness and large size of such condensers require that very high foundation supports be provided for the turbine. This also necessitates a great structural height for the turbine housing.
Heretofore, in order to reduce such large structural volume, U.S. Pat. No. 3,147,599 disclosed an arrangement wherein a condenser was disposed on both sides of a turbine and wherein the turbine and the condenser were enclosed within a boxlike housing. However, this type of housing is not free of problems regarding its stability in that the turbine proper, must be supported in the interior of the housing by an additional foundation support. Also, the sealing of such a square housing and particularly the sealing of the access opening for the disassembly of individual turbine parts can be obtained only at high extra cost and expenditure.
It is an object of the present invention to provide an arrangement of a condenser and low-pressure turbine which only requires a small structural volume which also has a large and efficiently arranged support capacity, and which may be readily sealed.
To this end and in accordance with the present invention, a low-pressure turbine and a condenser are enclosed in a cylindrical pressure-tight housing which supports both the low-pressure turbine and the condenser. The housing is supported on an external foundation. A removable V-shaped segment is included on the housing at an elevation above the turbine shaft and which extends over the entire longitudinal length of the housing, such V-shaped segment being of such width that the removal of the inside housings or turbine casings and of the rotors of the low-pressure turbine can be effected through the opening which remains after the V-shaped segment is removed.
Thus, the cylindrical housing offers a compact and warp-resistant type of construction so that the housing can support the condenser as well as the low-pressure turbine. The V-shaped segment opening on the upper part permits, on one hand, the easy removal of turbine parts while, on the other hand, providing for self-sealing at the separating line, or joint between the two parts upon re-installation of the V-shaped segment on the housing.
In addition various auxiliary elements and parts can be integrated into the housing. It is possible, for example, to dispose low-pressure preheaters below the low-pressure turbine inside the housing, the arrangement being such that the preheaters may be pulled out underneath the adjacent generator which is driven by the turbine. Furthermore, inlet lines for the auxiliary returns can be arranged to pass through one front face of the removable V-shaped segment. The inlets and outlets for the cooling water to the condenser may also be arranged to pass on one front face of the condenser. If the low-pressure turbine is of a multiflow arrangement, the bearing between the two low-pressure turbines may be separated from the condenser chamber, by curved partitions or separating walls and connected with the upper side of the housing through an access passage so that inspection of the intermediate bearing is possible.
The construction and arrangement of the invention however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:
FIG. 1 is a schematic side view of a steam turbine installation having a high, medium and low pressure turbine and also showing the generator which is driven by the turbines.
FIG. 2 is a top view of the installation shown in FIG. 1.
FIG. 3 is a view taken along the line III--III in FIG. 1 and showing the front end face of the low pressure turbine and condensor housing.
FIG. 4 is a view showing the rear end face side of the turbine and low-pressure turbine housing as seen from the generator.
FIG. 5 is a longitudinal cross-sectional view through the housing taken along the line V--V in FIG. 3.
FIG. 6 is a transverse cross-section view through the housing taken along the line VI--VI in FIGS. 1 and 5.
Referring to the drawings, FIGS. 1 to 4 show various outside views of a steam turbine installation. To facilitate the description and its comprehension, only very simplified illustrations have been selected and those parts that are not considered essential to an understanding of the present invention have not been included.
In the illustrated embodiment, a steam power plant installation comprises a high pressure turbine 1, a double-flow medium pressure turbine 2, and a low-pressure turbine disposed in a cylindrical housing 3. The turbines drive a generator 4.
The cylindrical housing 3 encloses a condenser and also the low pressure turbine. The housing 3 has on its upper side, a V-shaped segment 5 that extends over the entire longitudinal length of the housing 3 and which can be removed in an upward direction from the housing 3 so that the casings and rotors of the low-pressure turbine can be removed through the resulting opening. As seen particularly from FIG. 3, the outlet lines 6 from the medium pressure turbine 2 pass into the front face 7 of the housing 3 and lead, inside the housing 3 to the individual low-pressure turbine stages. At the same time, the front side of the V-shaped segment 5 is provided with two connections 8 for the over-production or auxiliary return lines.
FIG. 4 is a view as seen from the direction of arrow A in FIG. 1, that is from the generator side, and shows low pressure preheaters 9 disposed below the low-pressure turbine. These low pressure preheaters 9 can be pulled out from beneath the generator 4, that is between the latter and its foundation supports 10.
The inlet lines 11 and the outlet lines 12 for the cooling water of the condenser are also led to and from the condenser tubes at the faces of the housing 3.
FIG. 5 is a longitudinal section through the housing 3 showing two double-flow low pressure turbines 13. The turbine shaft 14 for the turbines 13 is supported in hearings 15,16 and 17 with the front and rear bearing 15 and 17 being supported by foundation columns 18 and by the generator foundation 10 respectively. The center bearing 16 is mounted on the housing 3 through vertical carrier plates 31 (FIGS. and 6) formed as part of the condenser support walls. The housing 3 itself is supported on a separate outside-lying foundation 22 by means of brackets or abutments 20 and hinged supports 21 as can best be seen in FIGS. 3 and 6.
As can best be seen in FIG. 6, the two condenser sections 23, that is the two sections which include the condenser tubes 24, are disposed parallel to the machine axis and on both sides of the low pressure turbine 13. Each condenser section 23 is arranged in a segment which may subtend or occupy a quarter of the circumference of the condenser housing 3. The steam pouring out from the exhaust pipes of the low pressure turbines 13 (one of the pipes 25 being shown in section in FIG. 5 with the last row of turbine blades 26) can thus directly discharge into the condenser sections 23. This means that a condenser pressure will prevail in the interior of the entire housing 3 so that the housing itself must be designed appropriately pressure-tight which is particularly enhanced, however, by the cylindrical form of construction. The housing for the low pressure turbines 13 can be supported on projections 34 on the condenser support walls.
Below the low pressure turbines 13 and within the housing 3, are disposed low pressure preheaters 9 which are connected to the turbines 13 through suitable steam draw off lines 27.
The center bearing 16 for the low pressure turbine is separated from the internal condenser housing proper by means of curved sheets of metal 19 and can be reached or is accessible through an upwardly extending passageway or chute 28. In the cross-sectional view of FIG. 6, the contour 29 of the front face of the V-shaped removable segment 5 is illustrated by broken lines. As can be easily determined from this cross sectional view, after segment 5 is removed, it is a relatively simple matter to dismantle in an upward direction the housing of the low-pressure turbines 13, as well as other turbine parts, and to move them in an axial direction over generator 4. During the re-installation of segment 5, a particularly good sealing is provided at joint 29, since the latter abuts and fits closely at the opposite housing joint due to the inclined or wedge shaped mating surfaces.
Installed into the segment 5 is also a curved sheet of metal 30 which has suitable openings not shown in the drawing. As a result, the upper area enclosed by the metal sheet 30 can be used as a plenum chamber or over-production area so that the steam arriving via inlets 8 in the front-face side 7 can settle in this chamber and flow downward into the actual condenser chamber.
The condensate collects in a hot well 33 below the preheater 9 and can be drawn off therefrom.
This cross-sectional view in FIG. 6 also illustrates the steam over-flow or return lines 8 which lead over connections, not shown in drawing, to the intakes of the low pressure turbine 13. Other illustrated channels 32 which lead from the outside through housing 3, serve the supply and measuring lines of the turbine bearings.
The described arrangements of the condenser and low pressure turbines in a cylindrical housing thus provides a very compact and stable type of construction which eliminates high foundations and long exhaust lines for the turbine steam. In addition, the cylindrical configuration provides a good pressure-tightness for the housing.
Upon a study of this disclosure it will be apparent to those skilled in the art that the invention permits various modifications and may be given embodiments other than those particularly illustrated and described herein, without departing from the essential features of the invention and within the scope of the claims annexed hereto.