EP2240696B1 - Inlet connecting piece for an axial-flow compressor - Google Patents

Description

The invention relates to an inlet connection for an axial compressor, in particular a turbocompressor, with an inlet housing, in which a bearing housing is arranged with a first fluid axially in the flow direction of a fluid to be compressed bearing for a rotor of the axial compressor, wherein the bearing housing connected to the inlet housing via an inlet strut is, which is connected in an end cross section with the inlet housing.

Such intake struts are purely radial in conventional axial compressors, ie. parallel to a normal plane to the longitudinal axis of the inlet nozzle, so that the bearing center of the first or front bearing is arranged axially in the flow direction of a fluid to be compressed substantially at the level of the center of area of this end cross-section, in other words the bearing axially centrally in the inlet strut under the transition is arranged in the inlet housing.

In particular, a piercing point of a bearing axis through a plane of symmetry of a symmetrical bearing, a center of mass of the bearing, the geometric center between the axial end faces of the bearing or a pressure point of the bearing are referred to as the bearing center point.

Since the inlet struts, in particular for reasons of strength and production, are often connected relatively far forward to the inlet cross-section of the inlet connection with the inlet housing in order to be able to support, for example, against corresponding reinforcements of the inlet housing or to avoid greatly varying wall thicknesses during prototyping, this is also the first one or front bearing arranged correspondingly far forward, so that there is a relatively large bearing distance to a second, rear bearing of the rotor of the axial compressor, which is arranged in the flow direction behind the first bearing.

In the inlet struts, one or more fluid passages may be formed. Such fluid passages can serve, for example, the lubrication of the bearing and for this purpose open into the bearing housing on the one hand in or near the bearing and on the other hand with a Schmiermittelver- or disposal, for example via grease nipples, lines, passages in adjacent housing parts or the like, be connected outside of the inlet housing. In order to minimize both the length of the fluid passage and thus the weakening of the bearing housing supporting the inlet strut and the effort to their - usually cutting - production, such fluid passages are so far essentially radially.
As a result, a bearing supplied by the radial fluid passage has to be arranged axially at the level of the outlet opening of the fluid passage from the inlet housing, which also disadvantageously increases the bearing center distance of the rotor.
However, a larger bearing center distance can adversely affect the rotor dynamics.

From the EP 122 328 A1 is an inlet nozzle according to the preamble of claim 1 is known.
Object of the present invention is therefore to provide an improved inlet nozzle available.
To solve this problem, an inlet nozzle according to the preamble of claim 1 is further developed by at least one of its characterizing features. Claim 15 provides an axial compressor with such an inlet connection under protection, the dependent claims relate to advantageous developments.
An inlet connection according to the invention is provided for an axial compressor, in particular a turbocompressor, and may preferably be detachably or fixedly connected or integrally formed therewith. It has an inlet housing, the interior of which preferably tapers in the flow direction of a fluid to be compressed. In the inlet housing, a bearing housing is arranged, which receives a front or first bearing for a rotor of the axial compressor. This may in particular be a radial bearing, a thrust bearing or a radial-axial bearing. This bearing is axially in the flow direction of a fluid to be compressed, a first, ie front bearing, wherein the rotor in further Bearings can be supported, which have a greater axial distance to an inlet cross-section of the inlet nozzle.

The bearing housing is supported in the inlet housing via one or more inlet struts. Several inlet struts can be distributed equidistantly over the circumference of the bearing housing or have different angular distances from each other. While equidistantly distributed inlet struts the flow in the bearing housing homogeneous and thus little disturbing, inlet struts with different angular distances to each other can be adapted to constructional boundary conditions of the housing, in particular external leads, ribs, different wall thicknesses or the like.

One or more inlet struts are connected in each case an end cross section of the corresponding inlet strut with the inlet housing. In particular, one or more, preferably all inlet struts may be integrally connected to the inlet and / or bearing housing, for example by primary molding. Similarly, one or more inlet struts can also be connected to the entry and / or bearing housing after the prototyping, for example welded or screwed. According to the invention, a fluid passage is formed in at least one inlet struts. This can be provided in particular for supplying and / or removing lubricant to the bearing for the impeller. A fluid passage can likewise serve for supplying and / or removing cooling fluid, in particular cooling air, and / or a blocking fluid, in particular blocking air, in order to cool the axial compressor or to avoid a lubricant outlet into the axial compressor. Other fluids, such as a hydraulic fluid, in particular a controlled bearing, can flow through the fluid passage. In particular to the aforementioned functions, a fluid passage in a preferred embodiment in or in the vicinity of the bearing can open into the bearing housing. In addition or as an alternative to a fluid, the fluid passage described so far only for the sake of simplification may, for example, also be designed to guide cables, lines or the like, for example electrical and / or optical lines for sensors in the bearing housing.

According to the invention, it is proposed that a fluid passage at least partially encloses an acute angle with a normal plane to the longitudinal axis of the inlet nozzle, ie obliquely to the axial direction of the inlet nozzle, in particular from radially outside to radially inside in the direction of flow of the fluid to be compressed.
This constructive change compared to conventional, purely radially extending fluid passages, it is advantageously possible to move the bearing in the flow direction of the fluid to be compressed axially backwards so shorten the bearing center distance to reduce rotor dynamic problems or to avoid. At the same time, it becomes possible to optimally arrange feed lines to the fluid passages on the outer surface of the inlet housing, for example in the flow direction of the fluid to be compressed, and thus to provide reinforcements such as ribs or the like on the outer surface of the inlet housing in the area of the inlet strut (s).
The bearing center of the first bearing is in the flow direction of a fluid to be compressed axially at least 0.1 times, preferably at least 0.15 times, more preferably at least 0.2 times and in particular at least 0.25 -fold the chord length of the end cross-section disposed behind the center of area of the end cross-section. In this case, the chord length is the maximum extent of the end cross-section in the axial direction, ie in the flow direction of a fluid to be compressed, which corresponds, for example, to its diameter in the case of a circular end cross-section, and to its large radius in the case of an elliptical cross-section. The first bearing is arranged behind the center of area of an end cross-section , This advantageously the bearing distance to the center of mass of the rotor and - if present - shortened to a second, rear bearing of the rotor of the axial compressor, which is arranged downstream of the first bearing in the flow direction.
In this case, the first bearing, in particular behind the first two thirds of the chord length, ie at least 0.17-fold, preferably after the first three quarters of the chord length, ie be arranged at least 0.25-fold behind the center of area of the end cross-section.

If the bearing housing is connected to the inlet housing via a plurality of inlet struts, the bearing center of the first bearing is axially behind at least 0.1 times, 0.15 times, 0.2 times or 0.25 times the chord length of the end cross section arranged the surface center of the end cross-section of at least one inlet strut. Thus, it is also possible for inlet struts to be present, with respect to whose end cross-section the first bearing is arranged axially in front of or in the center of the surface. In a preferred embodiment, the bearing center of the first bearing is arranged axially at least 0.1 times, 0.15 times, 0.2 times or 0.25 times the chord length of the end cross section behind the surface centers of the end cross sections of all inlet struts ,

The bearing center no longer has to lie within the chord length of the end section (s) projected onto the longitudinal axis of the entry socket, but can also be arranged axially behind the end section (s). Equally, however, it can also be located within the chord length of the end cross section projected onto the longitudinal axis of the entry stub, in particular at most 0.75 times, in particular at most 0.5 times the chord length of the end cross section behind the center of the face cross section be.

If the first bearing is offset axially to the rear relative to the end cross-section of an inlet strut, it can be operated particularly well by obliquely extending fluid passages in this inlet strut.

In each case several, in particular two or three fluid passages can be formed in one or more inlet struts, wherein at least one, preferably several, particularly preferably all fluid passages form an acute angle with a normal plane to the longitudinal axis of the inlet nozzle. Such fluid passages may preferably run substantially parallel to one another, which is the production simplified. Likewise, however, they may also include different angles with the normal plane so as to define in particular optimal paths between exit positions on the inlet housing and on the bearing housing. In this way, for example, fluid passages opening into the bearing housing close to one another can be connected to supply lines at the inlet housing that are axially remote from one another, and vice versa.

In two inlet struts, a different number of fluid passages may be formed so as to optimally distribute, for example, supply and discharge lines. Also fluid passages in the same or different inlet struts need not have the same diameter, but may, for example, be adapted to the nature and quantity of the added or discharged medium.

One or more fluid passages may be substantially rectilinear so as to form the same acute angle everywhere with a normal plane to the longitudinal axis of the inlet nozzle. Such fluid passages are particularly easy to produce by drilling and to consider in the design.

The angle formed by such a substantially rectilinear fluid passage with a normal plane to the longitudinal axis of the inlet nozzle can preferably be in the range between 10 ° and 40 °, in particular in the range between 20 ° and 30 °. This represents a good compromise from shortening the bearing center distance and increasing the manufacturing effort.

One or more fluid passages may also have a kinked profile, so that at least a portion of this fluid passage forms an acute angle with a normal plane to the longitudinal axis of the inlet nozzle. By contrast, other sections of such fluid passages, for example, can extend substantially in the radial direction of the inlet housing. In this way, the advantages of purely radial and inclined fluid passages can be interconnected.

The angle which forms such an oblique section of a fluid passage with a bent course with a normal plane to the longitudinal axis of the inlet nozzle is preferably in the range between 60 ° and 80 °, in particular in the range between 65 ° and 75 °. Since here only a shorter distance in the radial direction to compensate for the axial offset between inlet and outlet of the fluid passage available stands, such oblique sections preferably have larger angles to the normal plane than kinkless fluid passages.

In a preferred embodiment, two or more fluid passages open into a common portion that communicates with the interior of the bearing housing. In particular, this section may extend obliquely, while the fluid passages opening into it preferably extend essentially in the radial direction of the inlet housing. As a result of such, substantially purely radially extending, fluid passages ver- or disposed points can be fed through a common inclined section, which advantageously reduces the production cost and the weakening of the inlet strut.

A radial axis through the center of area or center of gravity of at least one inlet strut can also - at least in sections - form an acute angle with a normal plane to the longitudinal axis of the inlet nozzle. For example, an inlet strut having a constant cross section can be inclined overall, in particular in the direction of flow of a fluid to be compressed towards the bearing housing tapering, be formed. Such a swept inlet strut is particularly suitable for receiving in particular straight-line fluid passages. In particular, for their inclusion, but also for receiving kinked fluid passages and for supporting an axially rearwardly displaced first bearing, an inlet strut can also extend substantially in the radial direction of the inlet housing and widen towards the bearing housing, so that the center of area or center of gravity displaced towards the bearing housing in the flow direction of a fluid to be compressed to the rear.

• Fig. 1 einen Eintrittsstutzen nach einer Ausführung der vorliegenden Erfindung im Halbschnitt; und
• Fig. 2 den Eintrittsstutzen nach Fig. 1 im perspektivischen Viertelschnitt.

Further advantages and features emerge from the subclaims and the following exemplary embodiments. This shows, partially schematized:

• Fig. 1 an inlet nozzle according to an embodiment of the present invention in half section; and
• Fig. 2 after the inlet pipe Fig. 1 in perspective quarter section.

Fig. 2 shows the cut out lower, seen in the flow direction of a fluid to be compressed left, a quarter of an inlet nozzle according to an embodiment the present invention in perspective view, Fig. 1 a horizontal section in Fig. 2 ,

The inlet nozzle has an inlet housing 1 for collecting and supplying a medium to a turbo-compressor (not shown). In the inlet housing 1, a bearing housing 2 is arranged, which has a substantially cylindrical shape, with the medium to be compacted in the flow direction (from left to right in the figures), front hemispherical end face. In the bearing housing 2, a radial bearing 3 for a rotor with impeller of the turbocompressor (not shown) is formed, the bearing center point 3a is located axially in the center of the bearing ring shown.

The bearing housing 2 is connected to the inlet housing 1 via three, four or more inlet struts, wherein in Fig. 2 a lower (cut) and a left (partially hidden) inlet strut 4 are visible, in Fig. 1 the left inlet strut 4.

In a modification, not shown, two or more blind struts are additionally arranged in the upper half of the inlet housing, which are not connected to the bearing housing.

In the Fig. 1 shown left inlet strut 4 is integrally connected to the inlet housing 1 and is in its the inlet housing 1 facing end cross section in this over. The center of area 10 of this end cross-section is in Fig. 1 drawn and is located axially in front of the bearing center point 3a, which in relation to this area center point by the 0.375-fold in the flow direction of a fluid to be compressed axially to the rear (to the right in Fig. 1 ) is offset.

In the left inlet strut 4 three fluid passages 5 are formed, one of which in Fig. 1 left, front fluid passage 5.1 (dash-dot in Fig. 1 ) serves the guidance of lines for sensors to the bearing 3 and in the vicinity of the bearing 3 before this opens into the bearing housing 2, a middle fluid passage 5.2 (drawn in Fig. 1 ) the supply of lubricant to the bearing 3 and opens in the bearing 3 in the bearing housing 2, and a in Fig. 1 right, rear fluid passage 5.3 (double-dashed in Fig. 1 ) serves the supply of sealing air into the bearing housing 2 and opens in the vicinity of the bearing 3 after this in the bearing housing 2.

These fluid passages 5 are formed as through-holes and therefore extend substantially straight. They close an acute angle of about 23 ° with a normal plane to the longitudinal axis of the inlet nozzle (vertical plane perpendicular to the plane of the drawing Fig. 1 ) or the complementary angle of about 67 ° with the longitudinal axis.

In the lower inlet strut 4, two fluid passages 6 are formed, which serve for the removal of lubricant from the interior of the bearing housing 2. These fluid passages 6 form sections an acute angle with a normal plane to the longitudinal axis of the inlet nozzle. For this purpose, they have a kinked course, wherein in each case a substantially extending in the radial direction portion 61 and 6.2 merges into a two fluid passages 6 common portion 8, which forms an acute angle of about 72 ° with a normal plane to the longitudinal axis of the inlet nozzle ,

This common inclined section 8 extends in the longitudinal direction of the inlet housing 1 (from left to right in FIG Fig. 1 ) and ends at the end in a circular segment-shaped annular groove 7, which is formed at right angles to the section 8 and extends over a range of 70 ° in the lower half of the bearing housing 2. About the arranged behind the bearing 3 annular groove 7 and the interior of the bearing housing 2 towards common open portion 8, which extends from the annular groove 7 below the radial bearing 3 forward through to the extending in the radial direction sections 6.1, 6.2, communicate the two fluid passages with the interior of the bearing housing. 2

Also with respect to the center of area 10 of the lower inlet struts 4 is the bearing center of the bearing 3, as in Fig. 2 recognizable, offset axially to the rear and lies in the last third of its projected to the longitudinal axis 9 chord length.

As in particular in Fig. 1 clearly visible, the inlet struts 4 extend substantially in the radial direction (from top to bottom in FIG Fig. 1 ). In order to have sufficient material for the oblique fluid passages 5 and the oblique, common section 8 and to support the bearing center well on both sides, the inlet struts 4 at their in the flow direction of the fluid to be compressed (right in Fig. 1 . 2 ) rear trailing edge a substantially dreickförmigen approach 4.1. A radial axis through the surface centers of the inlet struts 4 therefore has in this section with the paragraph 4.1 at an acute angle with a normal plane to the longitudinal axis of the inlet nozzle.

LIST OF REFERENCE NUMBERS

1

inlet casing

2

bearing housing

3

radial bearings

3a

Bearing center

4

inlet strut

4.1

approach

5.1-5.3

Fluid passage (for air, lubricant or cable)

6.1, 6.2

fluid passage

7

ring groove

8th

common section

9

longitudinal axis

10

Area center of the end cross-section

Claims (15)

1. An inlet connector for an axial compressor, in particular a turbocompressor, with an inlet housing (1), in which a bearing housing (2) with an, in flow direction of a fluid to be compressed, axially first bearing (3), in particular a radial and/or axial bearing, for a rotor is arranged, wherein the bearing housing (2) is connected to the inlet housing (1) via at least one inlet brace (4), which in a front cross section is connected to the inlet housing, wherein in the at least one inlet brace (4) at least one fluid passage (5, 6) is formed, which at least in sections forms an acute angle with a normal plane to the longitudinal axis of the inlet connector, characterized in that the bearing centre point of the bearing (3) in the flow direction is ranged axially at least by 0.1 times the chord length as maximum extension of the front cross section in the axial direction behind the centre of area of the front cross section.
2. The inlet connector according to Claim 1, characterized in that the bearing centre point of the bearing (3) in the flow direction is arranged axially at least 0.15-times in particular at least 0.2-times in particular at least 0.25-times of the chord length of the front cross section behind the centre of area of the front cross section.
3. The inlet connector according to Claim 1 or 2, characterized in that the bearing housing (2) is connected to the inlet housing (1) via multiple, in particular three or four inlet braces (4).
4. The inlet connector according to Claim 3, characterized in that the bearing housing (2) is connected to the inlet housing (1) via three or more evenly or unevenly distributed inlet braces, wherein one or more inlet braces are embodied as blind braces.
5. The inlet connector according to any one of the preceding claims, characterized in that in at least one inlet brace (4) multiple, in particular two or three fluid passages (5.1, 5.2, 5.3; 6.1, 6.2) are formed.
6. The inlet connector according to Claim 3 and 4, characterized in that in a first inlet brace (4) multiple fluid passages (6.1, 6.2) and in another inlet brace (4) a number of fluid passages (5.1, 5.2, 5.3) that is distinct thereof is formed.
7. The inlet connector according to any one of the preceding claims, characterized in that at least one fluid passage (5) extends substantially linearly, so that it forms the same acute angle with a normal plane to the longitudinal axis of the inlet connector everywhere.
8. The inlet connector according to Claim 6, characterized in that the angle formed by a substantially linearly extending fluid passage (5) with a normal plane to the longitudinal axis of the inlet connector, is in the range between 10° and 40°, in particular in the range between 20° and 30°.
9. The inlet connector according to any one of the preceding claims, characterized in that at least one fluid passage (6) has a folded course, so that at least one section (8) of this fluid passage forms an acute angle with a normal plane to the longitudinal axis of the inlet connector.
10. The inlet connector according to Claim 8, characterized in that the angle formed by a section (8) of a fluid passage (6) with folded course with a normal plane to the longitudinal axis of the inlet connector, is in the range between 60° and 80°, in particular in the range between 65° and 75°.
11. The inlet connector according to any one of the preceding claims, characterized in that at least two fluid passages (6.1, 6.2) open into a common section (8), which communicates with the interior of the bearing housing (2).
12. The inlet connector according to any one of the preceding claims, characterized in that a fluid passage is formed for feeding and/or discharging lubricant to the bearing (3) for the impeller.
13. The inlet connector according to any one of the preceding claims, characterized in that a fluid passage (5, 6) opens into the bearing housing (2) in or in the vicinity of the bearing (3).
14. The inlet connector according to any one of the preceding claims, characterized in that a radial axis through the centre of areas of at least one inlet brace forms an acute angle with a normal plane to the longitudinal axis of the inlet connector at least in sections.
15. An axial compressor, in particular turbocompressor, with an inlet connector according to any one of the preceding claims.

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