EP3141761A1 - Spiral housing, radial turbo machine, method for assembly - Google Patents

Abstract

Spiral casing (VC) of a radial turbomachine (RTM) comprising a collecting spiral (CV) extending in a spiral-like manner (CD) about an axis of rotation (X) of the turbomachine (RTM), comprising a radial diffuser (RTF), which is radially conducting between an impeller (IMP) and the collecting spiral (CV), the radial diffuser (RDF) on at least one axial side of a first diffuser disc (DF1) and on the other axial side a partial radial section is bounded by a second diffuser disk (DF2), wherein the radial diffuser (RTF) has guide vanes (DV) which segment the radial diffuser (RTF) in a radial area in the circumferential direction (CD) into flow passages, wherein the second diffuser disk (DF2) - Closing an opening (OP) to the interior of the radial diffuser (RDF) - is releasably secured to the volute casing (VC). To increase the efficiency and reduce effort, it is provided that the guide vanes (DV) are detachably fastened to the first diffuser disk (DF1). To save effort and costs, it is proposed that the guide vanes (DV) are detachably fastened to the first diffuser disk (DF1).

Description

The invention relates to a spiral casing of a radial turbomachine, comprising a collecting spiral extending spirally in the circumferential direction about an axis of rotation of the turbomachine, comprising a radial diffuser, which is radially conducting between an impeller and the collecting spiral, wherein the radial diffuser on an axial side of a first Diffuser disc and on the other axial side is limited at least over a partial radial section of a second diffuser disc, wherein the radial diffuser vanes, which segment the radial diffuser in a radial region in the circumferential direction in flow passages, wherein the second diffuser disc - an opening to the interior of the radial diffuser - is releasably secured to the volute.

In addition, the invention relates to a radial turbomachine with a corresponding volute casing and a method for mounting the volute casing by utilizing the structural features.

At radial turbomachinery, in particular, if these are formed as part of Getriebeturboverdichtern regularly Nachleitbeschaufelungen be used in the radial flow channel of the spiral housing. Such arrangements are already out of the US 4,877,369 A1 known concerning diffusers with a Leitbeschaufelung, as well as from US 4,824,325 A1 , Concerning a volute casing at the exit from a radial turbocompressor, US Pat WO 2015/077380 A1 already state of the art. The figure of KR 2014106975 A shows a radial turbocompressor, probably as part of a Getriebeturboverdichters in one-stage design with flying storage, the impeller or the impeller outlet side empties into a radial diffuser, downstream of a collecting spiral is arranged.

The Leitbeschaufelung in the radial diffuser at the exit from the impeller or the impeller are provided, since with the connection to the radially outflow impeller, the crescent-shaped blades align the flow for the purpose of improving the efficiency and expansion of the efficient usable travel range of the compressor. Conventional designs usually provide that the Leitbeschaufelung formed directly on a diffuser disc integrally or machined out, in particular milled.

For the purpose of mounting this Leitbeschaufelung is inserted axially into the spiral housing as part of the radial diffuser. Often it happens here that the maximum radial outer dimension of the diffuser disk comprising the guide vanes is radially bounded by the opening of the spiral housing. This limit is also subject to the front side milled diffuser blades. From an aerodynamic point of view, it regularly happens that the diffuser blades would preferably result in a better efficiency and an even greater driving range of the machine with a longer extent extending radially outwards. Purely from the aerodynamic design, the vanes would protrude beyond the other outer radius of the diffuser disk or opening. As a compromise solution, the diffuser blades are aerodynamically designed with this radial extent, which extends radially beyond the opening available for mounting. The projecting portion of these diffuser blades is then simply omitted or milled off, so that an assembly of the machine is possible. In this context one speaks also of cropped vanes. Accordingly, there is the aerodynamically not optimal implementation of the radial diffuser between the impeller or impeller outlet and the entry into the collecting spiral.

Another disadvantage of the milled design is that the already radially relatively large blank of the diffuser disc axially large enough for training the guide vanes must be performed. This relatively large blank also requires a relatively large machine tool for the milling of the vanes, so that the production costs increase significantly.

To avoid the cited disadvantages, a spiral housing or a radial turbomachine or a method for mounting the spiral housing of the aforementioned type with the additional features of the respective independent claims is proposed. The respective dependent claims contain advantageous developments of the invention.

Under a spiral or under spiral, the invention basically understands a curve that runs around a point or an axis and depending on the viewer's perspective of this / r away or approaches. The spiral housing has, in this sense, at least one boundary wall extending along a circumferential direction, which behaves exactly geometrically with respect to the rotation axis. This at least one boundary wall may be a radial or an axial or an obliquely bounding to these directions wall of the collecting spiral. Preferably, the collecting spiral is round in cross-section and changes the cross-sectional area along the circumferential direction.

In the conceptual world of the invention, indications such as radial, tangential, axial always relate to the axis of rotation of the radial turbocompressor, unless otherwise indicated. The terms "inner", "outer" with semantically related terms always refer to the interior of the radial turbomachine, in which the impeller is arranged and which is bounded by the volute casing or on the area outside the volute casing, which do not belong to the interior is.

The inventive modular splitting between the diffuser disk and the guide vanes results in greater flexibility with regard to the design of the radial diffuser and the assembly. In addition, only a smaller one Blank for the diffuser disk needed, the vanes can be made of blanks of a much smaller dimension. Basically, the invention is directed to volute with a radial diffuser having non-adjustable vanes. The vanes are fixed in their angular position. In principle, the guide vanes may also have a plurality of stages, which are arranged radially one behind the other, at least not all of which are radially located on the same diameter with their leading edge.

A preferred field of application of the invention are radial turbomachines in which the impeller is formed in diameter larger than one meter. The invention can be used particularly advantageously for transmission turbo compressors in which the second diffuser disk is provided axially between the transmission or the transmission housing and the impeller.

Particularly expediently, the guide vanes are detachably fastened to the first diffuser disk by means of fastening elements. Here, it is particularly useful if the opening is formed such that the fasteners can be solved accessible or secured externally accessible through the opening, which is formed closable by means of the second diffuser disc. It makes sense here if the vanes abut the second diffuser disk with an axial end side in the closed state of the volute casing. This contact reduces unwanted bypass flow adjacent the flow passages formed by the vanes.

The second diffuser disk can also have recesses for this axial end face of the guide vanes, which can additionally reduce the bypass flow and optionally fix the guide vanes in their position in a form-fitting manner. Another advantage of the adjacent contact between the second diffuser disc and the axial end face of the guide vanes comes into play when the fasteners are at least partially disposed in recesses, which in this axial end face are provided axially extending, such that when mounted second diffuser disc, the second diffuser disc covers the mouths of the recesses for the fastening elements in particular with respect to the flow. In this way, the flow at these recesses can not cause unwanted turbulence and possibly lead to erosion damage and further the fasteners are secured by the concern of the second diffuser disc on the front side and the covering of the recesses against complete release or detachment.

For flow considerations and from a mechanical point of view, it makes sense if the first diffuser disk has recesses at the locations of the guide vanes, wherein the guide vanes may have a base, wherein the attachment of the vanes to the first diffuser disk provides that the base of the vanes each in Axially guided guided into the recess. In this way, a positive connection perpendicular to the axial direction due to the fitting of the base into the recesses. The base of the guide vanes may either have exactly the profile of an airfoil of the guide vanes or deviate from this profile of the airfoil. Since the airfoil profile is regularly a relatively complicated contour, which requires a high production cost, it makes sense if the socket has a simpler geometry, so that the recess into which the socket is inserted, also has only a simple cross-sectional geometry. In this case, it is expedient for the base to have a different geometry relative to the airfoil and to be somewhat larger in relation to the airfoil with respect to a surface-normal direction of the airfoil. For the sake of simplicity, the blade can be cylindrical, that is with a constant profile cross-section.

The advantages of the invention come in a development particularly useful for carrying, when a radial extent of the vanes in the final assembly position on the maximum Outside radius of the opening goes out, such that a purely axial movement of the guide vanes in the final assembly position through the opening is not possible, but at least one radial movement must be made in addition. Optionally, a movement in the circumferential direction can be superimposed.

In this way, the additional freedom due to the modularity of the invention, the separation of the vanes is exploited by the diffuser disc while preventing the opening to be closed with the second diffuser disc is radially expanded.

A further advantageous embodiment of the invention provides that the axial height of the base of the guide vane in the region which extends beyond the radial extent of the opening is reduced compared to the other radial region, such that a pivoting movement of the guide vane into the recess during assembly is. With the Einschwenkbewegung is meant in the terminology of the invention that the guide vane can be introduced into the recess first approaching the mounting end position obliquely to the axial direction and obliquely to the radial direction with the socket first with the axially reduced height before the vane completely in the mounting position can be advanced radially and the base can be inserted into the recess with rotation of the vane about an axis of rotation, before the vanes is fastened with the fasteners.

The inventive method for mounting the spiral housing provides that, following the provision of the collecting spiral, the guide vanes are introduced individually into a final assembly position. In this case, the already defined pivoting movement is carried out for each guide blade, before the guide blade is fastened in the end position to the first diffuser disk. After all vanes have been fastened to the first diffuser disk in its end position, the opening of the volute casing is closed by means of the second diffuser disk. If necessary, find other assembly steps, which are not in essential connection with the invention, also take place between these steps described.

In the following the invention with reference to a specific embodiment with reference to drawings is described in detail. The invention is not limited to this particular embodiment and, moreover, it is possible to arbitrarily combine the subject matter of the claims with each other without an explicit reference being provided, as far as the person skilled in the art recognizes such combinations as meaningful.

Figur 1

eine dreidimensionale Darstellung eines erfindungsgemäßen Spiralgehäuses einer Radialturbomaschine,

Figur 2

ein Längsschnitt durch einen Teil der Radialturbomaschine im Bereich des Radialdiffusors, und

Figur 3

eine einzelne Leitschaufel in dreidimensionaler Wiedergabe.

Show it:

FIG. 1

3 shows a three-dimensional representation of a spiral housing according to the invention of a radial turbomachine,

FIG. 2

a longitudinal section through a portion of the radial turbomachinery in the region of the radial diffuser, and

FIG. 3

a single vane in three-dimensional rendering.

FIG. 1 schematically shows three-dimensionally an inventive volute VC of a radial turbomachine RTM. In a radial region of a radial diffuser RTF guide vanes DV are provided, which - as well as in FIG. 2 - Align process fluid emerging from an impeller IMP with respect to a downstream inflow angle into a collection vial CV. The impeller is arranged in rotation about an axis of rotation X, around which the collecting spiral CV and the radial diffuser RTF extend in the circumferential direction. The guide vanes DV segment the radial diffuser RTF located radially between the impeller outlet and the inlet into the collecting spiral CV in the circumferential direction into flow passages for the process fluid. The radial diffuser RTF is bounded on the left by a first diffuser disk DF1 and opposite on the right side by a second diffuser disk DF2. The vanes DV are located between these two diffuser disks DF1, DF2. On the first diffuser disk DF1 the guide vanes are releasably attached.

As well as in FIG. 3 can be seen, the guide vanes on an airfoil AF and a base PF. The pedestal PF is made thicker than the profile of the cylindrical airfoil AF in the normal direction of the airfoil surface and has a simple geometry. In the final assembly position in the first diffuser disk DF1 of the guide vanes DV, the base PF is in each case fitted in a form-fitting manner in a recess RS provided in the first diffuser disk DF1 for the guide blade. The base PF is in this case designed such that the recess can be produced simply with a cylindrical milling cutter in a rectilinear movement in the first diffuser disk DF1. The second diffuser disk DF2 is in FIG. 2 represented and in the FIG. 1 omitted an opening OP releasing. Through the opening OP, the individual guide vanes are inserted in their final assembly position in the first diffuser disk DF1 in the recesses RS. This insertion corresponds to a pivoting movement or a pivoting. A purely axial movement of the guide vanes DV in this final assembly position is not possible because the opening OP is not designed to large enough. Instead, the Einschwenkbewegung is that an axially and radially combined movement is provided for the introduction of the base PF in the recess RS. The guide vanes DV are axially fitted with only a small clearance in the flow channel of the radial diffuser. So that the guide vanes DV can still be moved with their radially projecting end in the final assembly position, the base PF has in the region of radially over a reduced axial height or bevel FA. In this way, the guide vanes can be approximated obliquely to the axis of rotation X of the final assembly position and moved radially and axially far enough that initially the radially projecting side of the guide vane DV of the Montageendposition or the first diffuser disk DF1 is closest. With simultaneous radial Axial movement and rotation of the vane DV about an axis perpendicular to the axis of rotation X and substantially perpendicular to the side surface of the base PF, it is possible to insert the guide vane DV in the radial diffuser in the final assembly position, although the opening OP has only a smaller radial extent than the mounting end of the Guide vane DV has a maximum diameter.

Following insertion of the pedestal PF of the vane DV into the recess RS, fasteners FE are used to secure the vane DV of the first diffuser disc. Appropriately screws are used for this purpose, which are screwed into depressions FERE, or recesses, in particular bores-provided on a first axial end face FFA1 of the guide vanes DV. The depressions FERE in which the fastening elements FE have been inserted are covered by the second diffuser disk when it is in its final assembly position and at least partly abuts or approaches this first end face FFA1 of the stator vanes in this final assembly position Scope of possible manufacturing tolerances).

1. 1) Bereitstellen der Sammelspirale,
2. 2) Einschwenken der Leitschaufeln DV,
3. 3) Befestigen der Leitschaufeln DV in ihrer Montageendposition mittels Befestigungselementen FE,
4. 4) Wiederholen des Schrittes 3), bis alle Leitschaufeln DV in ihrer Montageendposition befestigt sind,
5. 5) Verschließen der Öffnung OP mittels der zweiten Diffusorscheibe DF2.

The assembly method according to the invention essentially takes place in the steps comprising:

1. 1) providing the collecting spiral,
2. 2) pivoting of the guide vanes DV,
3. 3) fixing the guide vanes DV in their final assembly position by means of fastening elements FE,
4. 4) repeating step 3) until all vanes DV are mounted in their final assembly position,
5. 5) closing the opening OP by means of the second diffuser disk DF2.

Claims (9)

Spiral casing (VC) of a radial turbomachine (RTM), comprising a collecting spiral (CV) extending in a spiralwise direction (CD) about an axis of rotation (X) of the turbomachine (RTM),
comprising a radial diffuser (RDF) which is radially conducting between an impeller (IMP) and the collection scroll (CV),
wherein the radial diffuser (RDF) is bounded on one axial side by a first diffuser disk (DF1) and on the other axial side by at least a partial radial portion of a second diffuser disk (DF2), the radial diffuser (RTF) having guide vanes (DV), segmenting the radial diffuser (RTF) in a circumferential radial area (CD) into flow passages, the second diffuser disk (DF2) releasably securing an opening (OP) to the interior of the radial diffuser (RDF) to the volute (VC);
characterized in that
the guide vanes (DV) are releasably secured to the first diffuser disk (DF1). Spiral housing (VC) according to claim 1,
wherein the guide vanes (DV) on the first diffuser disc (DF1) are releasably secured by means of fastening elements (FE), in particular such that the fastening elements (FE) through the opening (OP) can be solved accessible or attached externally. Spiral housing (VC) according to at least one of claims 1, 2,
the first diffuser disk (DF1) having recesses (RS) at the locations of the guide vanes (DV),
wherein the guide vanes (DV) have a base (PF), wherein the attachment of the guide vanes (DV) to the first diffuser disk (DF1) provides that the pedestals (PF) of the guide vanes (DV) each to lead in the axial direction the recesses (RS) are used. Spiral housing (VC) according to at least the preceding claim 3,
wherein the guide vanes (DV) have an airfoil (AF) directly following the pedestal (PF), the airfoil (AF) extending axially from the first diffuser disk (DF1) to the second diffuser disk (DF2). Spiral housing (VC) according to at least one of the preceding claims 2, 3, 4,
wherein the guide vanes (DV) abut the second diffuser disk (DF2) with an axial end face (FFA1), wherein the fastening elements (FE) are at least partially disposed in recesses (FERE) axially extending in this axial end face (FFA1) are such that when the second diffuser disk (DF2) is mounted, the second diffuser disk (DF2) covers the mouths of the recesses (FERE) for the fastening elements (FE). Spiral housing (VC) according to at least one of the preceding claims 1 to 5,
wherein a radial extension of the guide vanes (DV) in the final assembly position beyond the maximum outer radius of the opening (OP), such that a purely axial movement of the guide vanes in the final assembly position through the opening (OP) is not possible, but in addition must be a radial movement , Spiral housing (VC) according to at least the preceding claim 3,
wherein the axial height of the base (PF) of the guide vane (DV) is reduced in the region which extends beyond the radial extent of the opening (OP) with respect to the other radial region such that a pivoting movement of the guide vane into the recess during assembly allows is. Radial turbomachine (RTM) with a spiral housing (VC) according to at least one of the preceding claims 1 to 7. Method for assembling a spiral housing according to at least one of the preceding claims 1 to 7 with the following steps: a. Providing the collecting spiral (CV), b. Inserting the vane (DV) into a mounting end position of the vane on the first diffuser disk (DF1) also at least partially radially in the region that extends radially beyond the radial extent of the opening (OP), moving the vane (DV) to the final assembly position relative to the first diffuser disk (DF1) and the other volute casing (VC) takes place in the manner of a Einschwenkbewegung, c. Attaching the guide vane (DV) to the first diffuser disk (DF1 d. Repetition of steps 2., 3. for several guide vanes (DV), e. Closing the opening (OP) by means of the second diffuser disk (DF2).

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