Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D3/00—Machines or engines with axial-thrust balancing effected by working-fluid
  • F01D3/04—Machines or engines with axial-thrust balancing effected by working-fluid axial thrust being compensated by thrust-balancing dummy piston or the like

Definitions

• the invention relates to a rotary machine, in particular a turbine, pump or compressor, with at least one rotor and at least one process fluid, which surrounds the rotor at least partially, wherein the rotor has at least one compensating piston, for influencing an axial thrust of the rotor, wherein the compensating piston at least one diameter change of the rotor, wherein at least one shaft seal is provided which seals a first space in which a first pressure prevails from a second space in which a second pressure prevails such that at least temporarily a pressure difference between the first and the second space is applied and a first shaft seal is arranged on the balance piston such that a first change in diameter the pressure of the first space and a second change in diameter is exposed to the pressure of the second space.
• Balancing pistons on rotary machines are part of the usual assemblies, especially in steam turbines.
• a pressure build-up or a pressure reduction of the process fluid takes place along a relaxation or compression path in at least partially axial direction of the rotor, wherein the rotor itself or its associated element in areas of varying diameter, such as wave heels, exposed to the respective different applied pressures are.
• rotating blades produce here as well as in the circumferential direction continuous shaft paragraphs an axial thrust that these elements transmit as axial force in the rotor.
• a thrust bearing In order for a thrust bearing to be designed in a meaningful size under these operating conditions, it is necessary to compensate for these forces by appropriate opposing forces elsewhere.
• a control set the pressure in the pressure chambers, so that the desired residual thrust is always formed.
• the described balancing effect can only be achieved if either the pressures on the balance piston have a particularly high difference or the
• Compensating piston diameter is designed very large.
• the shaft seal provided on the compensating piston requires sufficiently large axial space to achieve the required sealing effect.
• Both large diameter and large axial space cause on the one hand undesirable rotordynamic effects in the form of vibrations and on the other hand high costs due to the additional material requirements for both the rotor and the surrounding components, in particular for the housing.
• the invention has therefore taken on the task of developing a rotary machine with a balancing piston of the type mentioned in such a way that with the same thrust compensation only a reduced space is required.
• the formation of the balancing piston having a plurality of spaces, each separated by shaft seals from each other to form a pressure difference and which spaces are limited by at least one change in diameter of the rotor, allows the reduction of the diameter of the balance piston without reducing the thrust balance potential. Also, by the inventive multi-stage design of the balance piston (when a stage of a balance piston as an arrangement of a
• a particularly advantageous embodiment of the invention provides that the compensating piston is formed as a direct result of changes in diameter of the rotor, which is formed in a longitudinal extension of the rotor in the following order:
• Diameter reduction in each case a shaft seal between a respective stationary wall and the rotor is provided, so that - a first pressure chamber having the first diameter expansion as a boundary wall, a second pressure chamber having the first diameter reduction as a boundary wall, a third pressure chamber, the second diameter expansion as a boundary wall and a fourth pressure space has the second diameter reduction as a boundary wall.
• Understood compensating piston it is in this advantageous development of a four-stage arrangement, which may have the same thrust equalization potential at the same largest and smallest diameters of the respective stages, as a conventional balance piston.
• an arrangement according to the invention can also have more than four of the above-defined stages, for example 5, 6, or more.
• the shaft seals are each formed between the pressure chambers as a brush seal or a mechanical seal. These gaskets have a better sealing effect compared with conventional labyrinth seals, so that a higher axial extent over a smaller axial extent
• Particularly useful is the formation of pressure channels to the respective pressure chambers, so that can make the differential pressures required for the compensation by setting a certain pressure in the pressure chambers.
• the actuator In order to enable an adaptation of the thrust balance to different operating conditions, it may additionally be useful to provide at least one actuator or a valve in at least one pressure channel, by means of which the pressure in the connected pressure chamber is adjustable.
• the actuator allows a dynamic pressure regulation, which is preferably caused depending on the respective operating point of a central control.
• FIG. 1 shows a steam turbine as an example of a rotary machine according to the invention
• FIG. 2 shows a detail X of FIG. 1 with a conventional design of a balancing piston
• Figure 3 shows the detail X of Figure 1 with an inventive design of
• Figure 4 is a schematic representation of a rotor of conventional design with different
• Diameters and the balance piston and Figure 5 is a schematic representation of the rotor with inventive design of the
• FIG. 1 shows a rotary machine 1, namely a steam turbine 2, in which fed-in live steam 3 is depressurized as it flows through a blading 4 onto steam 5 of a lower pressure level in the region of an outflow 80.
• the axial thrust 8 is supported on a thrust bearing 9.
• a compensating piston 10 is provided, which is designed as a shaft shoulder on the rotor 6.
• FIGS. 2 and 3 show the detail X with the
• Balancing piston 10 in conventional construction or in accordance with the invention training.
• the compensating piston 10 of conventional design shown in FIG. 2 has in the axial direction of the rotor 6 from left to right a first pressure chamber 11, a first diameter change 21, a first shaft seal 31, a second pressure chamber 12 with a second diameter change 22.
• Axially in front of this described arrangement is a shaft labyrinth seal 82, by means of which the first pressure chamber 11 is sealed to the atmosphere 51.
• Axially behind the arrangement described as compensating piston 10, or on the part of the end pointing into the turbine interior of this arrangement is another
• Wave labyrinth seal 52 by means of which the second pressure chamber 12 is sealed to an inflow 54 out.
• This wave labyrinth seal can be attributed to the balance piston 10.
• the applied pressure in the second pressure chamber 22 is higher than that in the first pressure chamber 11, so that the resulting from a balance of forces of the balance piston thrust directed against the thrust from the blading 4.
• FIG. 3 shows the arrangement according to FIG. 2 or the detail X of FIG. 1 with a design of the compensating piston 10 according to the invention.
• the compensating piston 10 is in this case formed with four pressure chambers 11, 12, 13, 14, each of which has a shaft seal 31, 32, 33 to have separation between them and at least one
• Diameter change 21, 22, 23, 24 of the rotor 6 are partially limited.
• the shaft seals 31, 32, 33 are formed as brush seals, so that for a conventional construction (Fig. 2) equivalent pressure difference between the pressure chambers 11, 12, 13, 14 only a small axial space is spent.
• Pressure chamber 13 are connected to pressure channels 42, 43 in connection, so that the second pressure chamber 12 has a higher pressure than the third pressure chamber 13.
• the second pressure chamber 12 has a higher pressure than the third pressure chamber 13.
• the third pressure chamber 13 applied pressure and the voltage applied in the second pressure chamber 12 and the fourth pressure chamber 14 pressure identical. Due to the permeability of the shaft seals 31 - 33 results in each case a flow according to the plotted arrows 61 - 66 due to
• Figures 4 and 5 show the diameter provided on the rotor 6 in conjunction with various pressures in the
• Pressure chambers 11-14 in cooperation with shaft seals 31-33.
• the first pressure chamber 11 is connected to the outflow via a pressure channel 71 and the second pressure chamber 12 is connected by means of a pressure channel 72 to a higher pressure level in the blading 4.
• Figure 5 shows that in addition to the first pressure chamber 11 and the second pressure chamber 12, a third pressure chamber 13 and a fourth pressure chamber 14 are also connected to the pressure levels at the outflow 80 and the blading 4 and achieved in this way, the double effect of the thrust compensation can be. Otherwise, with the same design of the steam turbine 2, the diameter of the compensating piston 10 in the embodiment according to the invention according to FIG. 5 would be smaller.
• an actuator 100 or valve can be provided in the pressure channel 71, by means of which the pressure in the pressure chambers 12, 13, 14 can be adapted to the current operating conditions.
• the actuator is controlled by a central controller 101.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
• Sealing With Elastic Sealing Lips (AREA)
• Sealing Devices (AREA)

Priority Applications (7)

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Publications (1)

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Cited By (6)

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Citations (4)

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• 2008
  • 2008-05-09 DE DE102008022966.0A patent/DE102008022966B4/de not_active Expired - Fee Related
• 2009
  • 2009-04-30 RU RU2010150344/06A patent/RU2507399C2/ru not_active IP Right Cessation
  • 2009-04-30 PL PL09742020T patent/PL2271827T3/pl unknown
  • 2009-04-30 ES ES09742020T patent/ES2392322T3/es active Active
  • 2009-04-30 WO PCT/EP2009/055271 patent/WO2009135802A1/de active Application Filing
  • 2009-04-30 JP JP2011507879A patent/JP5086471B2/ja not_active Expired - Fee Related
  • 2009-04-30 EP EP09742020A patent/EP2271827B1/de not_active Not-in-force
  • 2009-04-30 CN CN2009801167659A patent/CN102016231B/zh not_active Expired - Fee Related
  • 2009-04-30 BR BRPI0912209A patent/BRPI0912209A2/pt not_active IP Right Cessation

Patent Citations (4)

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