Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Casing with mounting means
Reexamination Certificate
1999-11-22
2001-05-15
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Casing with mounting means
Reexamination Certificate
active
06231305
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention:
The invention relates to a steam turbine installation having a steam turbine whose turbine rotor is mounted in an end bearing.
A steam turbine is normally used in a power plant installation to drive a generator or in an industrial installation to drive a working machine. For this purpose, the steam turbine is fed with steam, serving as a flow medium, which expands in the steam turbine and produces work. Following its expansion the steam usually passes via an exhaust steam housing of the steam turbine into a condenser that is arranged downstream of the latter and in which the steam condenses. The flow through the exhaust steam housing may be axial or radial. The condensate is then fed as feed water to a steam generator and, following its evaporation, passes again into the steam turbine, so that a closed water/steam loop is produced.
The turbine rotor of a steam turbine of this type is normally mounted in a number of axial and/or radial bearings. One of these bearings, also referred to as the end bearing, is arranged in the interior, for example in the inner hub, of the exhaust steam housing and is used to fix that end of the shaft of the turbine rotor which is located in the exhaust steam housing. The end bearing is normally constructed as a radial bearing, that is to say as a bearing that absorbs radial forces.
Commonly assigned, copending application Ser. No. 09/009,560 (German patent application DE 196 15 011 A1) discloses a steam turbine in which a bearing housing formed of bearing shells or halves and belonging to the end bearing of the turbine rotor is directly connected to the exhaust steam housing. For this purpose, the bearing housing of the end bearing is held centrally in the exhaust steam housing via supporting arms that are arranged radially. The bearing housing of the end bearing is arranged inside that spatial area through which steam flows during the operation of the steam turbine. However, the end bearing of a steam turbine designed in this way is particularly sensitive with regard to movements or stresses of the exhaust steam housing, for example from load changes. In addition, in the case of such a design, only a limited rigidity of the end bearing can be achieved. The arrangement of the bearing housing of the end bearing within the flow of steam also requires a high outlay in the sealing of the oil chamber with respect to the spatial area through which the steam flows.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of specifying a steam turbine installation of the above-mentioned type whose steam turbine has a high stability with respect to movements of the exhaust steam housing, with a particularly high rigidity of the end bearing. In addition, the intention is to permit the condenser to be erected without using a cellar or on level ground, with a particularly low outlay.
With the foregoing objects in view there is provided, in accordance with the invention, a steam turbine installation, comprising:
a steam turbine having an exhaust steam housing and a turbine rotor rotatably supported about a rotor axis in the exhaust steam housing;
a foundation block disposed below the exhaust steam housing and a support disposed on the foundation block and guided through and into the exhaust steam housing;
an end bearing rotatably supporting the turbine rotor on the support;
a plurality of supports disposed laterally of the exhaust steam housing substantially at an equal level with the rotor axis of the turbine rotor; and
a condenser detachably and rigidly connected to the exhaust steam housing and mounted in the supports.
In other words, the objects of the invention are satisfied by the end bearing which is held by a support guided through the exhaust steam housing of the steam turbine and supported on a foundation block. Further, the exhaust steam housing is detachably but rigidly connected to a condenser assigned to the steam turbine and the condenser is mounted in a number of supports which are arranged geodetically at the level of the main axis of the turbine rotor.
The invention is based on the consideration that, for high stability with respect to the movements of the exhaust steam housing, the end bearing should be decoupled mechanically from the latter. In addition, for high bearing rigidity, a mechanical connection of the end bearing to the foundation or base frame of the steam turbine should be provided. This can be achieved by a support for the end bearing being provided and, in turn, being supported directly on the foundation block.
The end bearing can be arranged in an inner hub of the exhaust steam housing.
The erection of the condenser without a cellar or on level ground is in this case permitted, while avoiding an unfavorable pressure loss, by dispensing with a bypass line which is usually connected between the steam turbine and the condenser. For this purpose, the condenser is connected directly to the turbine housing. The connection between the turbine housing and condenser should be particularly rigid in this case, in order to absorb frictional forces, in particular in the case of a different expansion behavior of turbine housing and condenser.
If the supports are arranged at the level of the turbine axis, thermal expansion of the steam turbine installation leads to a displacement of the condenser relative to its foundation, without any displacements in the vertical direction being able to occur. In order to particularly facilitate the displacement of the condenser in the horizontal direction, in order to avoid damage arising from thermal expansion, a multiple ball bearing is advantageously provided to mount the condenser.
In accordance with an added feature of the invention, the exhaust steam housing includes a plurality of pads each mounted in a respective sliding bearing.
In other words, the exhaust steam housing is expediently supported on the foundation via a number of pads arranged laterally on the exhaust steam housing. In this case, the pads should be arranged laterally on the exhaust steam housing in such a way that they absorb the torque on the exhaust steam housing caused by the turbine rotor, on account of being mounted in a respective sliding bearing. The turbine housing is in this case held at the center of the shaft by central guides at its front end and at its rear end. As a result of using sliding bearings to mount the pads, the steam turbine can be designed in such a way that thermal movements transversely with respect to the main axis of the turbine shaft arising from thermal expansion, for example in the case of a load change, do not lead to damage on the steam turbine.
In accordance with a concomitant feature of the invention, the condenser comprises a plurality of condenser elements with at least one pair of condenser elements disposed opposite one another on the exhaust steam housing. This is a configuration of the steam turbine installation which is particularly symmetrical and therefore particularly insensitive to thermal expansions.
The advantages achieved with the invention are in particular that, as a result of holding the end bearing directly on the foundation, particularly high rigidity of the end bearing can be achieved with particularly simple means. In addition, the end bearing is mechanically decoupled from the exhaust steam housing and is then therefore insensitive with respect to movements of the exhaust steam housing. As a result of holding the end bearing directly on the foundation, the bearing housing can moreover be arranged within a duct region, and therefore outside the spatial region through which steam flows. In this case, the outlay relating to sealing the end bearing with respect to the spatial area through which steam flows is particularly low.
As a result of the displaceable mounting of the condenser or of the condenser elements on the foundation, compensation for thermal expansions arising from load changes on the steam turbine is permitted in a particularly simple way, even when there is a rigid connection between the condens
Hintze Dietrich
Kraft Jürgen
Kuhn Helmut
Kupka Wolfgang
Greenberg Laurence A.
Lerner Herbert L.
Look Edward K.
McAleenan James M.
Siemens Aktiengesellschaft
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