TURBOMACHINE HAVING A TEMPERATURE-CONTROLLED COVER

Abstract

A turbomachine, comprising a lower housing part, an assembly inserted into the lower housing part from above, comprising two opposite housing covers and a rotor having a shaft, the rotor being fed through both housing covers, and an upper housing part that encloses the assembly from above and is fastened to the lower housing part, is provided. A shaft seal is arranged between the cover and the shaft. To maintain good function of the shaft seal during operation using cold or hot gases, at least one of the covers has a temperature-control means guided around the shaft, having a first and a second temperature-control channel, for controlling the temperature of the lid in the area around the shaft.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application No. PCT/EP2013/053911 having a filing date of Feb. 27, 2013, based off of DE 102012203144.8 having a filing date of Feb. 29, 2012, the entire contents of which are hereby incorporated by reference.

FIELD OF TECHNOLOGY

The following relates to a turbomachine having a lower housing part, an assemblage—which is placed in the lower housing part from above and comprises two mutually opposing housing covers and a rotor, guided between the two housing covers, having a shaft—and an upper housing part, which encloses the assemblage from above and is secured to the lower housing part.

BACKGROUND

Turbomachines are used to expand or compress gases. Thus, in the case of a turbine, inlet gases are introduced into the turbine at high pressure and expand there, giving off energy to the rotor. Compressors, on the other hand, are used to compress air or other gases to final pressures of up to 100 bar or more. In this case, it is also possible for aggressive gases, which are not intended to pass into the environment to be compressed. Accordingly, turbomachines should be sealed off such that the operating gases thereof cannot escape to the outside, or can escape to the outside only insignificantly, through the gaps between the shaft and the housing.

GB 219 016 A discloses a turbo-generator arrangement having a turbine arranged in a housing. A shaft of the turbine is mounted on separate pillow blocks arranged outside the turbine housing and in their own housings. The shaft mounts are oil lubricated, the bearing lubrication oil being located inside bearing housings of the pillow blocks. Leakage steam from the turbine housing and radiant heat from the turbine housing can lead to undesirable heating of the bearing lubrication oil in the bearing housings of the pillow blocks. In order to counter this heating, GB 219 016 A provides screwed-on protective covers on the bearing housings, which covers are in each case water-cooled.

SUMMARY

An aspect relates to a turbomachine by means of which a reliable shaft seal can be achieved.

An aspect further relates to a turbomachine of the type mentioned in the introduction, in which at least one of the covers has a temperature-control means which is guided around the shaft and serves to control the temperature of the cover in the region around the shaft. A temperature-induced movement of the cover and the shaft with respect to one another can be countered.

Embodiments of the invention are based on the consideration that turbomachines are supplied with gases, the temperature of which can deviate sometimes considerably from the housing temperature of the turbomachine. Thus, for example, a turbine is supplied with a hot gas which expands in the turbine. Accordingly, some elements of the turbine are heated more by the hot gas than others. On the other hand, in the case of compressors, it is possible for extremely cold gases to be introduced and compressed, and so these gases cool the housing greatly at the location of the influx. Depending on the guiding of the operating gas through the turbomachine, different elements of the turbomachine cool at different rates. This also affects the two axial covers of the housing, which cool down or heat up relatively rapidly and greatly relative to the shaft and the housing.

In the case of shafts mounted in covers, a shaft seal is arranged between the shaft and the axial covers in which it is mounted, for example, a labyrinth seal or a fluid seal, having a gap between its rotating part on the shaft and its static part on the cover. If such a cooling or heating acts on the sealing region, this can lead to drawbacks with respect to the seal. In order to ensure an optimum seal, the gap should be as small as possible, but it has to be just large enough to avoid any abutment of the elements when the shaft is in operation. If the cover around the shaft cools down, it contracts such that the gap grows and the seal deteriorates. Conversely, the gap shrinks in the case of the cover heating up to a high temperature, for example, on the gas outlet side of a compressor. In order to avoid any abutment, the gap must in this case be chosen so as to be accordingly large enough in all permitted operational temperatures of the cover. Consequently, the seal gap must be dimensioned so as to be relatively large, which is not conducive to a good seal.

While this problem can be satisfactorily solved in smaller machines by good mounting of the shaft and appropriate dimensioning of the sealing gap, the problem is more difficult to solve in large machines. This is because the large dimensions of the cover mean that the thermal expansion per degree of temperature change is accordingly large, such that, if the cover cools down by 100 K, the sealing gap can move by several millimeters. Such temperature changes are more difficult to solve, by good thermal insulation of the cover and appropriate dimensioning of the sealing gap, in a manner which achieves a good sealing of the shaft.

Large machines are, inter alia, distinguished by the fact that their cover seal may be provided by two or more seal stages, wherein the inner stage has a larger diameter than the outer stage. In this construction, the cover may be pressed axially outward against the seals in order to provide a seal with respect to the housing. However, this embodiment makes it necessary to place the rotor, together with both covers, into the lower part of the housing as one assembly unit or as one assemblage.

By virtue of the temperature-control means of the cover, it is possible for the cover of large machines to be temperature-controlled, during operation, in the region around the shaft such that the gap does not change much during operation, such that it remains close to a gap width which is optimum for the seal, in terms of its dimensions. Elaborate thermal insulation of the cover may be dispensed with, or the cost of insulation may be kept low.

The temperature-control means may be a heating means and/or a cooling means. It can expediently be used both for cooling and for heating. This is of particular advantage in the case of a compressor since in this case the housing cover at the gas inlet is cooled by inflowing cold gases and the housing cover at the gas outlet is heated by outflowing hot gases. With the aid of the temperature-control means, which is expediently operated in the same manner in both covers, it is possible for the housing cover at the gas inlet to be heated and the housing cover at the gas outlet to be cooled.

The turbomachine may be an expansion machine, such as a turbine, or a compressor, for example, a turbocompressor, in particular a single-spool radial compressor. The assemblage may contain further elements in addition to the cover and the rotor, for example, a flow guiding device, in particular an inflow guiding device.

In one advantageous embodiment of the invention, the temperature-control means is guided about a shaft seal which is arranged between the cover and the shaft. In this manner the shaft seal can be protected, all around the ring, from the undesirable temperature, heat or cold, which acts from outside.

Temperature control of the cover, in particular of the sealing region of the cover about the shaft, may be performed in a plurality of ways. Heating coils may be used, although the electricity of these must be well-shielded. It is also possible to use heating pads, although these must be well-sealed and pressure-resistant. It is particularly advantageous if the temperature-control means has a first temperature-control duct in the cover which is fluidically connected to a temperature-control fluid reservoir. In this manner, temperature-control fluid can be brought to a desired temperature and can be guided around the shaft or the shaft seal, where it gives off its heat or cold.

To that end, it is necessary for a temperature-control fluid to be present, which may be any appropriate fluid. If, however, the temperature-control fluid used is bearing oil which is provided for mounting the shaft, the bearing oil is then used for multiple purposes, such that a further fluid reservoir and an additional fluid temperature-control means may be dispensed with.

The temperature-control duct is advantageously machined directly into the cover, depending on the length, such that the temperature-control fluid flows directly through the cover. Particularly advantageously, the temperature-control duct is machined into the inner side of the cover. Since this inner side is in direct contact with the operating gas, it is particularly cold or hot, such that the cover is markedly cooled or heated from that point. If the temperature-control duct is machined into the inner side of the cover, this undesirable temperature effect can be counteracted particularly effectively. A flow guiding device, which may be an inflow guiding device or an outflow guiding device, may lie on the inner side of the cover.

In a further advantageous embodiment of the invention, the temperature-control means has a second temperature-control duct arranged radially outside the first temperature-control duct. By so doing, it is possible to achieve a particularly gap-free thermal shielding of the seal region. The second temperature-control duct may be directly connected to the first temperature-control duct, such that a flow passes through both ducts, one after the other, or they may be separate, such that for example a flow passes through them in parallel.

It is expedient for the temperature-control duct to be guided about the shaft in the shape of an open ring. In particular if, in this context, it lies in an axial plane, the ring must be open in order to permit an inlet and an outlet. By means of this opening in the ring, which in the following will be referred to as the gap free from temperature-control ducts, heat or cold can penetrate radially from outside into the inner region of the duct and thus to the shaft seal.

In order to avoid this, it is further proposed that the second temperature-control duct is guided about the first temperature-control duct such that a tangential gap, free from temperature-control ducts, in the region of the first temperature-control duct is shielded in the radially outward direction by the second temperature-control duct.

The closer a cover region is arranged to the shaft seal, the more important it is to precisely control the temperature thereof. In order to achieve this, it is advantageous if the two temperature-control ducts are connected to one another such that temperature-control fluid from the temperature-control fluid reservoir flows first through the radially inner temperature-control duct and thence into the radially outer temperature-control duct, before returning to the temperature-control fluid reservoir.

Undesirable heat or cold can penetrate to the shaft seal not just from radially outside but also in the axial direction. It is therefore advantageous for there to be temperature-control ducts having different functions, in particular a radial shielding function and an axial shielding function. Both functions may be achieved if both temperature-control ducts have a rectangular cross section and one of the temperature-control ducts has a longer extent in the axial direction and the other of the temperature-control ducts has a longer extent in the radial direction. A longer extent in the axial direction can achieve a radial shielding and a longer extent in the radial direction can achieve an axial shielding

Expediently, the radially outer temperature-control duct has a longer extent in the axial direction and the radially inner temperature-control duct has a longer extent in the radial direction. The radially innermost region can thus be most effectively shielded against heat or cold from an inflow guiding device.

In a further advantageous embodiment of the invention, a gas supply for a shaft seal is guided radially between two temperature-control ducts of the temperature-control means. It is thus possible for gas supplied to the shaft seal to be held at a desired temperature and thus a good seal to be maintained. The shaft seal may be a gas- or oil-operated fluid seal. A labyrinth seal is also possible.

The above-described properties, features and advantages of the invention, and the manner in which these are achieved, will be more clearly understood in conjunction with the following description of an exemplary embodiment which will be explained in more detail in conjunction with the drawings. The exemplary embodiment serves to explain the invention and does not restrict the invention to the combination of features indicated therein, nor in relation to functional features. In addition, suitable features of the exemplary embodiment may also be considered explicitly in isolation and combined with any one of the claims.

BRIEF DESCRIPTION

Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

FIG. 1. shows a schematic section representation of a turbomachine;

FIG. 2. shows an embodiment of a lower housing part of the turbomachine having an installed cover;

FIG. 3. shows a view in section of a radially inner part of the cover about the shaft with multiple temperature-control ducts; and

FIG. 4. shows an axial plan view of the guiding of two temperature-control ducts.

DETAILED DESCRIPTION

In large turbomachines, the housing is divided into a lower housing part and an upper housing part. In order to assemble the turbomachine, first of all the lower housing part is set up and then a rotor assemblage is inserted from above into the lower housing part. This is schematically illustrated in FIG. 1. The lower housing part 4 of the turbomachine 2 stands on a solid underlying surface and the assemblage 6 is lowered from above into the lower housing part 4. Subsequently, the upper housing part 8 is placed onto the lower housing part 4 and screwed together therewith, resulting in the overall housing 10. The assemblage is surrounded by the housing 10, wherein two covers 12 of the assemblage 6 remain visible from the outside and can also be designated part of the housing 10. The two covers 12 are in turn connected to the rotor 14, the shaft 16 of which is guided through the two covers 12 and is sealed off in the two covers 12 by way of a shaft seal (not illustrated). The rotor comprises, in addition to the shaft 16, multiple rotor disks of the turbomachine. The covers 12 and rotor 14 with the shaft 16, and also optionally further components, form the assemblage 6.

FIG. 2 shows a rough perspective illustration of the lower housing part 4 with one of the two covers 12. In this exemplary embodiment, the turbomachine 2 is a single-spool radial compressor having a gas inlet 18 and a gas outlet 20. The gas to be compressed flows into the turbomachine 2 through the gas inlet 18, is compressed by the rotation of the rotor 14 and leaves the turbomachine 2 in a compressed and heated state through the gas outlet 20. The lower housing part 4 is secured to the solid underlying surface via supports 22.

FIG. 2 does not show an assembled state of the turbomachine 2 since, for the sake of improved clarity, the cover 12 is illustrated on its own without the rotor 14 and the further opposite cover 12. FIG. 2 would be considered to be complete with the cover 12 shown being placed on the shaft 16 of the rotor 14 and the opposite cover 12 likewise being positioned on the shaft 16. In the state shown in FIG. 2, this assemblage 6 is then deposited in the lower housing part 4.

FIG. 3 shows a view in section of a radially inner part of the cover 12 about the shaft 16. Multiple seal elements 26 of a shaft seal, which atmospherically shields an inner gas region of the compressor 2 from the outer region of the compressor 2, are arranged in a sealing region 24. The cover 12 has, in the axial direction in the sealing region 24, a temperature-control means 28 which comprises multiple temperature-control ducts 32, 34. For the purpose of properly controlling the temperature of the sealing fluid, a fluid supply 36 for supplying gas or sealing oil to at least one of the seal elements 26 is arranged between the temperature-control ducts 32, 34. A mount 38 for the shaft 16 in a pillow block 40 is shown axially further out. A housing cover insert 42 of an inflow guiding device which steers the inflowing operating gas, which is to be compressed, to the blades of the rotor 14 is shown axially inside the cover 12.

The two temperature-control ducts 32, 34 are shown in a schematic axial section view in FIG. 4. Bearing oil as temperature-control fluid is stored in a temperature-control fluid reservoir 44, is pumped thence to a heater 46, which can also be used as a cooler for cooling the temperature-control fluid, where it is brought to a desired temperature, that is to say, it is cooled or heated with respect to the surroundings. The temperature-control fluid reaches the radially inner temperature-control duct 34 via a supply line 48 and flows about the shaft 16 (not shown) in annular fashion in a not fully closed loop, in order to reach the outer temperature-control duct 32 via a connecting duct 50. There, the temperature-control fluid flows in the opposite tangential direction in the outer temperature-control duct 32, again in annular fashion, about the shaft 16 in order to then be fed back to the temperature-control fluid reservoir 44 via an outlet 52.

The opposite tangential flow direction in the two temperature-control ducts 32, 34 produces an even tangential temperature control of the cover 12 about the shaft 16. The radially innermost temperature-control duct 34 is supplied, via the supply line 48, with temperature-control fluid directly from the heater 46, such that the temperature can be adjusted with precision there, which is particularly advantageous in the innermost region of the cover 12.

The two temperature-control ducts 32, 34 are guided with respect to one another in such a manner that the radially outer temperature-control duct 32 is guided radially about a tangential gap 54, free from temperature-control ducts, of the inner temperature-control duct 34 such that, in the region of the gap 54, the shaft 16 is shielded in the radial direction by the outer temperature-control duct 32.

The outer temperature-control duct 32 is formed as a radial duct; its purpose is first of all thermal shielding in the radial direction. Accordingly, its rectangular, elongate cross section is longer in the axial direction than in the radial direction. The radially inner temperature-control duct 34 is formed as an axial duct; its purpose is first of all thermal shielding in the axial direction. Accordingly, its rectangular, elongate cross section is longer in the radial direction than in the axial direction. Instead of the axial duct 34, a further radial duct may also be present.

Both temperature-control ducts 32, 34 are created in the inside of the cover 12. The axial duct 34 predominantly shields the cover 12 from cold from the flow guiding device or housing cover insert 42. The radial duct 32 shields the inner region of the cover 12 from cold from the gas inlet 18 which predominantly penetrates radially from outside inwards in the cover 12.

The inner region of the cover 12 is shielded, by all the ducts 32, 34, from the cold emanating from inflowing gas, which is to be compressed, such that the inner region of the cover 12 and thus also the shaft seal is kept within a desired temperature range.

FIGS. 3 and 4 show only that axial cover 12 of the housing 10 which is positioned at the gas inlet 18. However, the cover 12 at the outlet 20 is also formed in the same manner. It also contains the temperature-control ducts in the same configuration, which are connected to the temperature-control fluid reservoir 44 in parallel with the temperature-control ducts 32, 34 of the inlet-side cover 12. They are therefore supplied with the same temperature-control fluid which is guided, via supply lines 48, with the same temperature to both covers 12. Since the inlet-side cover 12 is cooled by the operating gas and the outlet-side cover 12 is heated, the same fluid takes on different functions in the two covers 12, namely heating in the inlet-side cover 12 and cooling in the outlet-side cover 12.

Although the invention has been illustrated and described in detail by means of the preferred exemplary embodiments, this does not mean that the invention is restricted by the disclosed examples and other variations may be derived herefrom by a person skilled in the art without departing from the scope of protection of the invention.

Claims

1. A turbomachine comprising:

a lower housing part;

an assemblage that is placed in the lower housing part from above and comprises two mutually opposing housing covers and a rotor, guided between the two mutually opposing housing covers, having a shaft; and

an upper housing part that encloses the assemblage from above and is secured to the lower housing part;

wherein at least one cover of the two mutually opposing housing covers has a temperature-control means which is guided around the shaft and serves to control the temperature of the at least one cover in a region around the shaft.

2. The turbomachine as claimed in claim 1, wherein a shaft seal is arranged between the at least one cover and the shaft and the temperature-control means is guided about the shaft seal.

3. The turbomachine as claimed in claim 1, wherein the temperature-control means has a first temperature-control duct in the at east one cover which is fluidically connected to a temperature-control fluid reservoir.

4. The turbomachine as claimed in claim 3, wherein the temperature-control fluid is bearing oil which is provided for mounting the shaft.

5. The turbomachine as claimed in claim 3, wherein the temperature-control duct is machined into an inside of the at least one cover.

6. The turbomachine as claimed in claim 3, wherein the temperature-control means has a second temperature-control duct arranged radially outside the first temperature-control duct.

7. The turbomachine as claimed in claim 6, wherein the second temperature-control duct is guided about the first temperature-control duct such that a tangential gap, free from temperature-control ducts, in a region of the first temperature-control duct is shielded in the radially outward direction by the second temperature-control duct.

8. The turbomachine as claimed in claim 6, wherein the first temperature-control duct and the second temperature-control duct are connected to one another such that temperature-control fluid from the temperature-control fluid reservoir flows first through the radially inner temperature-control duct and thence into the radially outer temperature-control duct, before returning to the temperature-control fluid reservoir.

9. The turbomachine as claimed in claim 6, wherein the first temperature-control duct and the second temperature-control duct have a rectangular cross section and the radially outer temperature-control duct has a longer extent in the axial direction and the radially inner temperature-control duct has a longer extent in the radial direction.

10. The turbomachine as claimed in claim 1, wherein a gas supply for a shaft seal is guided radially between the first temperature-control duct and the second temperature-control duct of the temperature-control means.