DE102017223791A1 - Shaft seal arrangement of a turbomachine, turbomachine - Google Patents

Abstract

The invention relates to a shaft seal assembly (SHA) of a turbomachine (TRM) comprising: a stator (STA), a rotor (ROT) rotatably mounted about an axis (X), a first shaft seal (SHS1), a second shaft seal (SHS2 wherein the first shaft seal (SHS1) and the second shaft seal (SHS2) are arranged in series for a sealing function between a high-pressure side (HPS) and a low-pressure side (LPS), the first shaft seal (SHS1) comprising a first rotating sealing element (RSE1) and a first upright seal member (SSE1) having a first annular seal gap (GS1) facing each other therebetween, the second seal member (SHS2) having a second rotary seal member (RSE2) and a second upright seal member (RSE2) forming a second annular sealing gap (GS2) between them facing each other, wherein the sealing gaps (GS1), (GS2) in an axial longitudinal section a first axial total extent (AG1) or a second axial total extent (AG2) and a first total radial extent (RG1) and a second total radial extent (RG2). In order to reduce the axial space in the interest of better rotor dynamics, it is proposed that the first shaft seal (SHS1) and the second shaft seal (SHS2) are arranged radially relative to each other, that individual shaft seals (SHS1 - SHS5) are arranged radially nested one inside the other.

Description

• einen Stator, einen Rotor, der um eine Achse drehbar gelagert ist, eine erste Wellendichtung,eine zweite Wellendichtung, wobei die erste Wellendichtung und die zweite Wellendichtung hinsichtlich einer Abdichtungsfunktion zwischen einer Hochdruckseite und einer Niederdruckseite in Reihe angeordnet sind.

The invention relates to a shaft seal arrangement of a turbomachine comprising:

• a stator, a rotor rotatably supported about an axis, a first shaft seal, a second shaft seal, wherein the first shaft seal and the second shaft seal are arranged in series for sealing function between a high pressure side and a low pressure side.

Arrangements of the type defined are already out of the DE 10 20 14 21 89 37 A1 or the DE 10 20 14 21 16 90 A1 known. Such shaft seal assemblies are a regular part of turbomachinery when at least one shaft end of the rotor of the turbomachine is led out of the housing. Since the housing of the turbomachine is generally a pressure vessel which has an overpressure relative to the environment in the interior during operation, the annular gap resulting between the shaft and the housing in the region of the shaft passage is sealed by means of a shaft seal. Such shaft seals are not completely leak-free by nature, with corresponding amounts of process fluid loss usually not uncontrolled escape into the environment, but be discharged controlled.

Known designs of such turbomachines are, for example Einwellenradialverdichter or so-called gear compressor. Corresponding Einwellenradialverdichter and associated components are already out of the WO2017137207-A1 . WO2017076584-A1 . WO2017076584 . WO2016026825-A1 . WO2016026825 . WO2015193269-A1 . WO2015193269 . WO2014037149-A1 . WO2014037149 . WO2012140197-A1 . WO2012136497-A1 . WO2012136496-A1 . WO2012104347-A1 . WO2010072780-A1 . WO2007137959-A1 . EP 1860362-A1 known.

Corresponding gear compressor or Getrieberadialturboverdichter and associated components are already out of the DE102015200439-A1 . WO2014060163-A1 . WO2012140197-A1 . WO2012104153-A1 . WO2012101208-A2 . WO2011036206-A1 . WO2010118977-A1 . WO2010058002-A1 . WO2010034602-A1 . WO2009144102-A1 . WO2009149798-A1 . WO2009000618-A1 . EP1965035-B1 . EP1965037-B1 . WO2008107280-A1 known.

At least some of the shaft seals of a corresponding shaft seal arrangement can be designed as oil-lubricated or gas-lubricated mechanical seals. Corresponding shaft seal assemblies comprise, if they meet corresponding relevant standards, in particular safety regulations, several individual shaft seals. These can be designed in various ways, for example as labyrinth seals or as oil or gas lubricated mechanical seals or as dry gas seals or as so-called HALO seals.

Seals of the type "HALO" are already out of the US 8,172,232 . US 8,002,285 . US 7,896,352 known.

The arrangement of multiple shaft seals in series with respect to any leakage path of the shaft seal assembly is conventionally relatively space consuming and significantly extends the need for axial length of the rotor. Accordingly, the influence of the space requirement on the rotor dynamics of corresponding turbomachines is negative. Naturally, the rotor dynamics constitute a decisive criterion for the possible operating range of a turbomachine, which usually rotates relatively quickly. Particularly in the field of application of such shaft seal arrangements for gear compressor, the axial length of the shaft seal arrangement forms a critical size, since typically the impeller of a centrifugal compressor are arranged together with the shaft seal at a free shaft end beyond a rotor supporting bearing in the region of the gearbox, from where the impeller driven or is driven off. The axial length of the shaft seal assembly thus contributes directly to the axial length of the free shaft end.

Based on the problem described above, the invention has taken on the task of reducing the axial space of a shaft seal arrangement defined above for a turbomachine. For this purpose, a shaft seal arrangement according to the independent claim 1 is proposed. The dependent claims include advantageous developments of the invention.

Terms such as axial, radial, tangential or circumferential direction refer to the central axis or axis of rotation of the rotor of a turbomachine, which is also a central axis of the shaft seal arrangement.

The mentioned in claim 1 high pressure side or low pressure side refers to the operation of the shaft seal assembly, wherein in operation on one side of the shaft seal, a higher pressure than on the other side. Accordingly, a possible direction of leakage, or the path of a any leakage, from the high pressure side to the low pressure side by the order of the sealing function of the shaft seal assembly in series with individual shaft seals of the assembly.

Characteristic of the invention is the radially nested arrangement of the individual shaft seals, which can also be referred to as an arrangement of the shaft seals in individual, in each other enveloping planes - or cylinder planes.

In nominal operation, the respective shaft seals of the shaft seal arrangement preferably operate without contact to form a sealing gap between a rotating and a stationary sealing element. The sealing gap may in this case be filled with process fluid or else with a sealing fluid, for example with a sealing gas or an oil film. The sealing gap here is in its entirety an annular three-dimensional shape. The wording of the statements about the sealing gap and its axial and radial extent refers, inter alia, to a longitudinal section through the shaft seal arrangement and in this case on the radial and axial extent of the individual sealing gaps. While the sealing gap has a three-dimensional annular shape, the longitudinal section through the sealing gap relates only to the longitudinal cross-section through the sealing gap in a single peripheral angular position. The axial extension means in the wording of the patent application accordingly the axial total extension of the longitudinal cross-section of the sealing gap in a single peripheral angular position. Mutatis mutandis this also applies to the radial extent or entire radial extent.

Decisive for the invention is that the individual shaft seals of the shaft seal arrangement are positioned radially in series with each other and are not arranged axially to each other. Each individual shaft seal, in particular preferably the corresponding sealing gap, therefore claims a radial area from a first radius to a second radius which has no intersection with the sealing gap of another shaft seal of this shaft seal arrangement.

Particularly preferably, the individual sealing gaps are arranged in close axial proximity to each other, so that there is only a small Axialbauraum for the entire shaft seal assembly. Accordingly, any leakage path throughout the shaft seal assembly preferably defines a serpentine shape in the longitudinal cross-section, with the leakage path alternating back and forth from one axial side of the assembly to the other axial side of the assembly.

In contrast to any tandem arrangements of conventional seals, the individual shaft seals of the arrangement according to the invention operate independently of one another, in particular the sealing elements and the carriers of the sealing elements of the individual shaft seals are not one-piece common components. Preferably, there is no fixed direct connection between the rotating sealing elements and / or the stationary sealing elements, wherein at least the rotating or standing sealing elements are axially movable relative to the respective opposite sealing element. Preferably, the standing element is axially movable and biased by an elastic element in the direction of the opposite rotating sealing element.

Particularly preferably, a third shaft seal is provided along the leakage path in series with the first shaft seal and the second shaft seal. This shaft seal is particularly preferably arranged between the first shaft seal and the second shaft seal. In the same way, the arrangement of the third shaft seal to the first shaft seal and the second shaft seal is also radially to the rotation axis while saving axial space.

An advantageous development of the invention provides that the first shaft seal and / or the second shaft seal is designed as a mechanical seal / are and the third shaft seal is designed as a labyrinth seal.

Another advantageous development provides that between the first shaft seal and the second shaft seal, the third shaft seal is arranged and a fourth shaft seal upstream along a leakage path in series with the first shaft seal, the second shaft seal and the third shaft seal is arranged. These shaft seal is arranged radially to the first, second and third shaft seal while saving axial space.

Particularly preferred is a development in which a fifth shaft seal is provided downstream of the first, second, third and fourth shaft seal in series with respect to a leakage path and radially to the other shaft seals while saving axial space.

Particularly preferably, the fourth and the fifth shaft seal are designed as labyrinth seals.

Particularly preferably, the rotating sealing elements of the individual shaft seals on a shaft shoulder of a rotor of Turbomachine attached, in particular on a Radallaufradrückseite. Here, the Radialaufradrückseite is the axially opposite to an inlet side of the radial impeller side.

The shaft seal assembly according to the invention develops the advantages particularly comprehensive, if this is part of a turbomachine and between a bearing and a bearing - in particular flying - supported impeller is arranged. The term "flying" here means that a bearing of the rotor is provided only on one axial side of the impeller.

• 1 eine schematische Darstellung eines Längsschnitts einer erfindungsgemäßen Wellendichtungsanordnung einer Turbomaschine
• 2 eine andere Wellendichtungsanordnung nach der Erfindung in schematischer Darstellung eines Längsschnitts

In the following the invention with reference to a specific embodiment with reference to drawings is described in detail. Show it:

• 1 a schematic representation of a longitudinal section of a shaft seal assembly according to the invention of a turbomachine
• 2 another shaft seal assembly according to the invention in a schematic representation of a longitudinal section

The 1 and 2 each show a schematic longitudinal section through a shaft seal arrangement according to the invention SHA , The longitudinal section shows the arrangement in the direction of an axis X , the rotor axis of a turbomachine TRM that is here with the cutting of a rotor RED and a stator STA. A shaft end of the rotor RED is through an opening of a housing of the stator STA passed therethrough and the resulting circumferentially extending gap between the rotor RED and stator STA by means of the shaft seal arrangement SHA sealed. The shaft seal arrangement SHA includes a first shaft seal Shs1 and a second shaft seal SHS2 , wherein the first shaft seal Shs1 and the second shaft seal SHS2 as mechanical seals SRS1 . SRS2 are executed. The two shaft seals Shs1 . SHS2 are in terms of a sealing function between a high-pressure side HPS (radially outside) and a low pressure side LPS (radially inward) arranged in series. The entire shaft seal arrangement SHA is located on the back of a rotor RED attributable impeller IMP that is, a process fluid flowing axially away from the shaft seal assembly PFL deflected in the radial direction. Both in the 1 as well as in the 2 are the first shaft seal Shs1 and the second shaft seal SHS2 designed as mechanical seals with a gas lubrication, the difference between the embodiment of 1 to the one of 2 It is that a between a rotating sealing element RSE1 . RSE2 and a standing sealing element SSE1 . SSE2 ring-shaped sealing gap GS1 in the 1 extends substantially radially and in 2 extends substantially obliquely (each in longitudinal cross-section).

With regard to the direction of a leakage path LEP from the high pressure side HPS to the low pressure side LPS are upstream of the first shaft seal Shs1 a fourth shaft seal SHS4 and downstream between the first shaft seal Shs1 and the second shaft seal SHS2 a third shaft seal SHS3 and downstream of the second shaft seal SHS2 a fifth shaft seal SHS5 arranged. Here are the first shaft seal Shs1 and the second shaft seal SHS2 as a mechanical seal SRS1 . SRS2 are formed and the third shaft seal SHS3 preferred as a labyrinth seal LB3 educated. The fourth shaft seal SHS3 and / or the fifth shaft seal SHS5 are preferred as a labyrinth seal LB4 . LB5 educated. The individual shaft seals of the shaft seal arrangement are arranged substantially radially relative to one another or radially nested one inside the other. In this way, axial space is saved. The rotor RED is by means of a warehouse BEA stored and due to the saving of the axial space in the shaft seal assembly SHA is the distance between the bearing BEA and the impeller IMP reduced. The impeller IMP is stored here overhung, which means that storage of the rotor RED only on one axial side of the impeller IMP is provided. The sealing column GS1 . GS2 . GS3 . GS4 . GS5 The individual shaft seals each have an axial extension AG1 - AG5 and a radial extension RG1 - RG5 , These extensions each relate to a longitudinal section through the annular sealing gap in a single peripheral angular position. The axial extents and the radial extents are each the total extension in this single circumferential angular position. The sealing column GS1 . GS2 . GS3 . GS4 . GS5 are rotationally symmetric, so that the individual (circumferential) angular positions do not differ.

The sealing column GS1 . GS2 extend in the embodiment of 1 with a gap longitudinal direction in cross-section substantially radially and the gap thickness axially. The sealing column GS3 to GS5 extend in the embodiment of 1 with a gap longitudinal direction in cross-section substantially axially and the gap thickness radially.

Each of the sealing gaps GS1 . GS2 . GS3 . GS4 . GS5 claims a certain radial area for itself, so that the individual radial areas of the individual shaft seals Shs1 - SHS5 have no overlap with each other. The axial extent of the entire shaft seal arrangement SHA is due to the radial interleaving of the shaft seal assembly SHA advantageous reduced. Accordingly, the individual axial extension regions may overlap with each other without causing spatial overlaps. Preferably, an axial distance between these axial extensions is less than the amount of the greatest radial extent of the individual sealing gaps GS1 - GS5 ,

The 2 shows a shaft seal assembly according to the invention, in which not all components and dimensions with the corresponding reference numerals, as in 1 , are provided.

The sealing column GS1 to GS5 extend in the embodiment of 2 with a gap longitudinal direction in cross-section substantially axially and the gap thickness radially. In principle, the sealing surfaces of the individual seals - ie the essential extent of the sealing gaps in cross-section - each be formed horizontally (parallel to the axial extension), vertically (perpendicular to the axial extension) or conically (obliquely to the axial extent).

A

Sperrgas,

B

Sekundäre Absaugung,

C

Sekundäres Sperrgas,

D

Primäre Absaugung,

E

Primäres Sperrgas

Basically, however, the same designations for functionally identical components apply here. In addition to the 1 are in the 2 still currents of functional gases or functional fluids from the seal away or registered to the seal out. Basically, in the embodiments of the 1 . 2 the function of the fifth shaft seal SHS5 the one of the oil separation, because the fifth shaft seal SRS5 adjacent to a radial bearing BEA is arranged. The first, second and third shaft seal serve the actual gas seal from the high pressure side HPS to the low pressure side LPS , The fourth shaft seal SHS4 is designed as a labyrinth seal and is intended to impurities from the high pressure side HPS or prevent from the process gas from penetrating into the first, second or third shaft seal. In addition, the labyrinth seals or the fourth shaft seal are used SHS4 , third shaft seal SHS3 and fifth shaft seal SHS5 as seals for emergencies, if the first shaft seal Shs1 or the second shaft seal SHS2 should be defective. The in the 2 indicated gas flows flow according to the directions of the arrow from or to the individual shaft seals Shs1 to SHS5 as follows:

A

Sealing gas,

B

Secondary suction,

C

Secondary sealing gas,

D

Primary suction,

e

Primary purge gas

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014218937 A1 [0002]
• DE 102014211690 A1 [0002]
• WO 2017137207 A1 [0003]
• WO 2017076584 A1 [0003]
• WO 2017076584 [0003]
• WO 2016026825 A1 [0003]
• WO 2016026825 [0003]
• WO 2015193269 A1 [0003]
• WO 2015193269 [0003]
• WO 2014037149 A1 [0003]
• WO 2014037149 [0003]
• WO 2012140197 A1 [0003, 0004]
• WO 2012136497 A1 [0003]
• WO 2012136496 A1 [0003]
• WO 2012104347 A1 [0003]
• WO 2010072780 A1 [0003]
• WO 2007137959 A1 [0003]
• EP 1860362 A1 [0003]
• DE 102015200439 A1 [0004]
• WO 2014060163 A1 [0004]
• WO 2012104153 A1 [0004]
• WO 2012101208 A2 [0004]
• WO 2011036206 A1 [0004]
• WO 2010118977 A1 [0004]
• WO 2010058002 A1 [0004]
• WO 2010034602 A1 [0004]
• WO 2009144102 A1 [0004]
• WO 2009149798 A1 [0004]
• WO 2009000618 A1 [0004]
• EP 1965035 B1 [0004]
• EP 1965037 B1 [0004]
• WO 2008107280 A1 [0004]
• US 8172232 [0006]
• US8002285 [0006]
• US 7896352 [0006]

Claims (16)

Shaft seal assembly (SHA) of a turbomachine (TRM) comprising: a stator (STA), a rotor (ROT) rotatably mounted about an axis (X), a first shaft seal (SHS1), a second shaft seal (SHS2), the first shaft seal (SHS1) and the second shaft seal (SHS2) are arranged in series for a sealing function between a high-pressure side (HPS) and a low-pressure side (LPS), characterized in that the first shaft seal (SHS1) and the second shaft seal (SHS2) are radial are arranged nested. Shaft seal arrangement (SHA) after Claim 1 wherein the first shaft seal (SHS1) comprises a first rotating seal member (RSE1) and a first upright seal member (SSE1) facing each other forming a first annular seal gap (GS1) therebetween, the second seal seal (SHS2) forming a second rotating seal member (SSS1) Sealing element (RSE2) and a second stationary sealing element (RSE2), which are a second annular sealing gap (GS2) between them facing each other. Shaft seal arrangement (SHA) after Claim 2 in which the sealing gaps (GS1, GS2) have in an axial longitudinal section a first axial overall extension (AG1) or a second axial overall extension (AG2) and a first overall radial extension (RG1) or a second overall radial extension (RG2), the first shaft seal (SHS1) and the second shaft seal (SHS2) are arranged radially relative to one another such that the first radial extent (AG1) and the second radial extent (AG2) do not radially overlap. Shaft seal arrangement (SHA) after Claim 1 . 2 or 3 , wherein the axial distance of the first annular sealing gap (GS1) to the second annular sealing gap (GS2) is smaller than the smaller radial extent (RG1, RG2) of the sealing gaps (GS1, GS2). Shaft seal arrangement (SHA) after at least one of Claims 1 - 4 , wherein the rotating sealing elements (RSE1, RSE2) are formed independently of one another without a fixed direct connection to one another and / or the standing sealing elements (SSE1, SSE2) are formed independently of each other without a fixed direct connection to each other, wherein at least one rotating sealing element (RSE1, RSE2) or a stationary sealing element (SSE1, SSE2) is designed to be axially movable independently of another stationary or rotating sealing element (SSE1, SSE2, RSE1, RSE2). Shaft seal arrangement (SHA) according to at least one of the preceding Claims 1 to 5 wherein a third shaft seal (SHS3) is arranged along a leakage path (LEP) in series with the first shaft seal (SHS1) and the second shaft seal (SHS2), wherein the third shaft seal (SHS3) upstream, downstream or between the first shaft seal (SHS3) SHS1) and the second shaft seal (SHS2), wherein the third shaft seal (SHS3) is arranged radially interleaved with the first and the second shaft seal (SHS1, SHS2). Shaft seal arrangement (SHA) after Claim 6 wherein the third shaft seal (SHS3) comprises a third rotary sealing element (RSE3) and a third stationary sealing element (SSE3) forming a third annular sealing gap (GS3) between them, the third sealing gap (GS3) being in an axial direction Longitudinal section has an axial extent (AG3) and a radial extent (RG3), wherein the radial extensions (RG1), (RG2), (RG3) of the first, second and third shaft seal (SHS1), (SHS2), (SHS3) do not overlap radially. Shaft seal arrangement (SHA) according to at least one of the preceding claims, wherein the first shaft seal (SHS1) and the second shaft seal (SHS2) as a mechanical seal (SRS1, SRS2) are formed and the third shaft seal (SHS3) is designed as a labyrinth seal (LB3). Shaft seal arrangement (SHA) according to at least one of the preceding claims, wherein the first sealing gap (GS1) and / or the second sealing gap (GS2) are conical. Shaft seal arrangement (SHA) according to at least one of the preceding Claims 6 - 9 wherein the third shaft seal (SHS3) is disposed between the first shaft seal (SHS1) and the second shaft seal (SHS2), a fourth shaft seal (SHS4) upstream along a leakage path in series with the first shaft seal (SHS1), the second shaft seal (SHS1). SHS2) and the third shaft seal (SHS3), wherein the fourth shaft seal (SHS4) is arranged radially nested to the first, the second and the third shaft seal (SHS1, SHS2, SHS3). Shaft seal arrangement (SHA) after at least the previous one Claim 10 wherein the fourth shaft seal (SHS4) comprises a fourth rotating seal member (RSE4) and a fourth standing seal member (SSE4) forming and facing each other a fourth annular seal gap (GS4), the fourth seal gap (GS4) being in one axial longitudinal section has an axial extent (AG4) and a radial extent (RG4), wherein the radial extensions (RG1), (RG2), (RG3), (RG4) of the first, second, third and fourth shaft seal (SHS1, SHS2, SHS3, SHS4) do not overlap radially. Shaft seal assembly (SHA) shaft seal assembly (SHA) according to at least one of the preceding Claims 10 - 11 wherein a fifth shaft seal (SHS5) is disposed downstream along a leakage path (LEP) in series with the first shaft seal (SHS1), the second shaft seal (SHS2) and the third shaft seal (SHS3), the fifth shaft seal (SHS5) radially nested to the first, second, third and fourth shaft seals (SHS1, SHS2, SHS3, SHS4). Shaft seal assembly (SHA) Shaft seal assembly (SHA) after at least the previous one Claim 12 , wherein the fifth shaft seal (SHS5) has a fifth rotary sealing element (RSE5) and a fifth stationary sealing element (SSE5), which form a fifth annular sealing gap (GS5) between them and face each other, wherein the fifth sealing gap (GS5) in a axial longitudinal section has an axial extent (AG5) and a radial extent (RG5), wherein the radial extensions (RG1), (RG2), (RG3), (RG4), (RG5) of the first, second, third, fourth and fifth Shaft seal (SHS1), (SHS2), (SHS3), (SHS4), (SHS5) do not radially overlap. Shaft seal arrangement (SHA) according to at least one of the preceding Claims 10 - 13 wherein the fourth shaft seal (SHS3) and / or the fifth shaft seal (SHS5) is / are formed as a labyrinth seal (LB4, LB5). Shaft seal assembly (SHA) according to at least one of the preceding claims, wherein the shaft seal assembly (SHA) comprises a shaft shoulder (SSH) on which the rotating sealing elements (RSE1, RSE2, RSE3) of the shaft seals (SHS1, SHS2, SHS3) are mounted. Shaft seal arrangement (SHA) after Claim 15 wherein the shaft shoulder (SSH) is part of a radial turbomachinery wheel (IMP).

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