EP3473861B1 - Castor wheel and method for manufacturing the same - Google Patents

Description

The invention relates to an impeller for a fan or a compressor and a method for producing such an impeller for a fan or a compressor.

Such wheels can be manufactured in a variety of ways.

One possibility for producing such impellers is purely welded constructions, in which the components of the impeller are prefabricated from sheet metal and then welded, with accessibility causing major problems due to the internal welds.

Another possibility for producing such impellers is casting processes, in which the casting has to be reworked and imperfections have to be corrected by repair welding, which causes problems in particular in the area of the impeller interior, especially in the area of the blade channels.

Another possibility is machining processes, whereby machining processes are primarily used for open impellers and cause massive problems for closed impellers.

For example, the reveals WO 2006/133363 A2 an impeller unit comprising a first main body and a second main body, the first main body forming at least a substantial part of an impeller disk and an impeller cover as well as a plurality of impeller blades and the second main body forms a remaining part of the impeller disk or the impeller cover. GB632,475 discloses a turbine wheel comprising a plurality of individual parts, including impeller blades, an upper envelope section and a lower envelope section, a flat inlet shroud, a cylindrical outlet shroud and a central safety ring, all of which individual components are welded together. Another example of an impeller is in CN1205399 described.

The invention is therefore based on the object of creating an impeller with a simple structure, which can in particular be produced using simple and cost-effective process steps.

This object is achieved according to the invention in an impeller of the type described at the outset in that the impeller has an impeller base body which comprises an impeller cover and impeller blades integrally formed on the impeller cover and that an impeller base is held on the impeller base body by welding it to the impeller base body and that the Impeller base is formed from several base segments welded to the impeller base body.

The advantage of the solution according to the invention can therefore be seen in the fact that the use of several floor segments allows a floor to be fixed to the impeller base body in a simple manner by a welding process that takes place from outside the impeller, in particular an outside of the floor segments.

No further information was provided in this context with regard to the design of the impeller base body.

An advantageous solution provides that the impeller base body comprises impeller blades which extend between the impeller cover and the impeller base up to outlet openings of the impeller.

Furthermore, it is preferably provided that the impeller base body comprises a hub, which is in particular integrally formed on it.

Furthermore, it is preferably provided that the impeller base body has impeller main blades as impeller blades, which are connected to the hub in particular in the area of their inlet-side ends and extend from these to the outlet-side ends.

Furthermore, it is advantageous for the efficiency of the impeller that the impeller base body has impeller intermediate blades as impeller blades, which lie between the main impeller blades and extend from inlet-side ends arranged at a radial distance from the hub to outlet-side ends.

Furthermore, it is preferably provided that the impeller base body has an inlet nozzle arranged on the impeller cover, through which the medium to be conveyed enters the impeller.

The inlet nozzle could, for example, be welded to the impeller cover.

It is preferably provided that the inlet nozzle is integrally formed on the impeller cover.

With regard to the design of the floor segments forming the impeller floor, no further information was provided in connection with the previous description of the solution according to the invention.

An advantageous solution provides that the floor segments forming the impeller base extend between two impeller main blades that are adjacent to one another or follow one another in a circumferential direction.

In particular, each of the floor segments is formed by a blank part made of flat material, which has main blade connection contours adjacent to the main impeller blades in comb areas.

Preferably, for the connection between the impeller base body and the base segments, each base segment is welded to the comb region of the impeller main blades along the main blade connection contours.

With regard to the design of the floor segments forming the impeller base, no further details were given in connection with the previous description of the solution according to the invention in the event that intermediate impeller blades are present.

An advantageous solution provides that the floor segments forming the impeller base extend between two adjacent main impeller blades and the at least one intermediate impeller blade located between the main impeller blades.

In particular, each of the floor segments is formed by a blank part made of flat material, which has main blade connection contours adjacent to the main impeller blades in comb areas and has intermediate blade connection contours adjacent to a comb area of the at least one intermediate impeller blade.

For the connection between the impeller base body and the base segments, it is preferably provided that each base segment is welded along the main blade connection contours to the comb region of the impeller main blades and along the intermediate blade connection contours to the comb region of the at least one intermediate impeller blade.

Furthermore, it is advantageously provided that the base segment is welded along a hub connection contour to a circumferential region of the hub extending between the main impeller blades.

It is particularly favorable if the base segments are welded by an I-seam to the comb areas of the main impeller blades and, if necessary, to the comb area of the at least one intermediate impeller blade.

Furthermore, it is preferably provided that the impeller has a support disk that stabilizes the impeller base in the area around the hub and, in particular, additionally stabilizes the connection between the base segments and the hub.

Such a support disk is preferably placed on the impeller base after the base segments have been welded to the impeller base body and, in particular, is connected to both the hub and the impeller base by welding in order, on the one hand, to keep the material thickness of the impeller base as low as possible and, on the other hand, to additionally maintain the connection to the hub to improve.

In addition, in the solution according to the invention it is preferably provided that the impeller base body has a stiffening ring formed on an outlet-side edge region of the impeller cover.

The stiffening ring could be connected to the impeller base body, for example by welding.

However, it is particularly advantageous if the stiffening ring is integrally formed on the impeller base body.

In addition, the invention also relates to a method for producing an impeller for a fan or a compressor, in which, according to the invention, an impeller base body, comprising an impeller cover and impeller blades integrally formed on the impeller cover, is produced by milling a blank and, according to the invention, an impeller base is formed on the impeller base body Welding several floor segments to the impeller base body is fixed.

The advantage of this solution is that the impeller base body can be produced by milling and, in particular, there is easy access to the interior of the impeller, which is still open at the bottom, and that, on the other hand, the impeller base can be produced in a simple manner by welding the base segments .

Furthermore, it is advantageous if the base segments are welded one after the other to the impeller base body, so that a simple manufacturing process for the impeller base can be implemented using simple means.

With regard to the production of the impeller base body, no further information was provided in connection with the previous process steps.

It is therefore preferably provided that the impeller main blades are formed onto the impeller base body by milling, the inlet-side ends of which attach in particular to a hub of the impeller base body and which extend to the outlet-side ends.

Furthermore, it is additionally provided that intermediate impeller blades are formed on the impeller base body by milling, which extend from an inlet end arranged at a distance from the hub to an outlet end, the outer ends preferably lying close to the outer contours of the impeller cover and the impeller bottom .

Regarding the insertion of the floor segments, no further information was provided in connection with the previous statements.

A particularly favorable solution provides for the base segments to be inserted between impeller main blades which are adjacent to one another or which follow one another in a circumferential direction.

This makes it possible to easily connect the base segments to the main impeller blades.

A particularly favorable solution in this regard provides that the base segments are welded to comb areas of the main impeller blade.

This makes it possible to achieve a simple and particularly stable connection between the floor segments and the main impeller blades.

In particular, the method according to the invention is carried out in such a way that, starting with a base segment, the base segments are welded to the impeller base body.

In order to be able to position the floor segments reliably relative to the main impeller blades, it is preferably provided that the floor segments are fixed by welding points before they are welded to the comb regions of the main impeller blades.

For fixation between the base segments and the comb regions of the impeller main blades, it is preferably provided that the base segments are welded to the impeller main blades with a continuous weld seam along their main blade connection contours.

With regard to the insertion of the base segments into existing intermediate impeller blades, no further information was provided in connection with the previous statements.

A particularly favorable solution provides that the base segments are inserted between adjacent main impeller blades and at least one intermediate impeller blade located between these main impeller blades.

This makes it possible to easily connect the floor segments to the main impeller blades and the intermediate impeller blade.

A particularly favorable solution in this regard provides that the base segments are welded to comb regions of the main impeller blade and a comb region of the at least one intermediate impeller blade located between the main impeller blades.

This makes it possible to achieve a simple and particularly stable connection between the base segments and the main impeller blades as well as the intermediate impeller blade located between them.

In particular, the method according to the invention is carried out in such a way that, starting with a base segment, the base segments are welded to the impeller base body.

In order to be able to position the base segments reliably relative to the main impeller blades and the intermediate impeller blade, it is preferably provided that the base segments are fixed by welding points before they are welded to the comb regions of the main impeller blades and the intermediate impeller blades.

For fixation between the base segments and the comb regions of the main impeller blades and the intermediate impeller blade, it is preferably provided that the base segments are welded with a continuous weld seam along their main blade connection contours to the main impeller blades and their intermediate blade connection contours to the respective intermediate impeller blade.

No further details have yet been provided regarding the production of the floor segments for welding into the impeller base body.

A particularly advantageous connection between the base segments and the comb areas of the main impeller blades and the intermediate impeller blades provides that the base segments are welded to the impeller base body with the comb areas of the main impeller blades and, if applicable, the intermediate impeller blades by I-seams.

Welding is preferably carried out by laser beam welding or electron beam welding.

In order to produce the floor segments precisely, it is preferably provided that the floor segments must be produced from a flat material by wire erosion.

In order to give the impeller base a precise shape on its outside, it is preferably provided that the impeller base body with the welded-in base segments is machined by turning an outside of the impeller base to achieve a flat surface, so that all material accumulations or other inaccuracies in the area that occur as a result of the welding Floor segments can be removed.

To improve the stability of the impeller base, it is preferably provided that a support disk is placed on the impeller base and connected to it.

The support disk could, for example, be glued to the impeller base.

However, it is particularly favorable if the support disk is welded to the impeller base with its outer contour, in particular with a fillet weld, so that a long-term stable connection is created between the support disc and the impeller base.

Furthermore, it is preferably provided that the support disk is connected to the hub with its inner contour surrounding the hub, in particular by means of an I-seam.

With regard to the design of the impeller base body, no further detailed information was provided in connection with the previous exemplary embodiments.

An advantageous solution provides that an inlet nozzle is arranged on the impeller base body in the area of the impeller cover.

Such an inlet nozzle could in principle be connected to the impeller base body by a welded connection.

However, it is particularly favorable if the inlet nozzle is shaped for the impeller base body during the milling process of the blank and is thus connected in one piece to the impeller base body.

In addition, it is preferably provided that a hub of the impeller is arranged on the impeller base body.

Such a hub could also be connected to the impeller base body, for example by welding.

However, it is particularly advantageous if the hub is formed for the impeller base body during the milling process of the blank, so that the hub is also arranged in one piece on the impeller base body.

Furthermore, in order to stabilize the impeller base body, in particular the impeller cover of the impeller base body, it is provided that a cover stiffening ring is arranged in an outlet-side region of the impeller cover.

This cover stiffening ring could also be connected to the impeller base body by welding it.

However, it is particularly favorable if the stiffening ring is formed in the course of milling the blank for the impeller base body. Further features and advantages of the present invention are the subject of the following drawings and the detailed description of an exemplary embodiment.

Fig. 1

eine perspektivische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Laufrads;

Fig. 2

einen Schnitt längs Linie 2-2 durch einen Laufradgrundkörper des erfindungsgemäßen Laufrads;

Fig. 3

eine Draufsicht auf den Laufradgrundkörper in Richtung des Pfeils A in Fig. 2;

Fig. 4

eine Draufsicht auf den Laufradgrundkörper in Richtung des Pfeils B in Fig. 2;

Fig. 5

eine Draufsicht auf ein erfindungsgemäßes Bodensegment zur Herstellung eines Laufradbodens des Laufrads;

Fig. 6

eine Draufsicht ähnlich Fig. 4 mit einem ersten in den Laufradgrundkörper eingesetzten Bodensegment;

Fig. 7

einen Schnitt längs Linie 7-7 in Fig. 6;

Fig. 8

einen Schnitt ähnlich Fig. 7 mit eingeschweißten Bodensegmenten;

Fig. 9

eine Draufsicht auf den Laufradgrundkörper gemäß Fig. 6 mit sämtlichen eingeschweißten Bodensegmenten zur Herstellung des Laufradbodens;

Fig. 10

einen Schnitt ähnlich Fig. 2 durch den Laufradgrundkörper mit eingeschweißten Bodensegmenten;

Fig. 11

eine Draufsicht auf den Laufradboden des Laufrads in Richtung des Pfeils C in Fig. 10 jedoch mit einer zusätzlich aufgelegten Stützscheibe und

Fig. 12

einen Schnitt längs Linie 12-12 in Fig. 11 durch das fertige Laufrad.

Show in the drawing:

Fig. 1

a perspective view of an exemplary embodiment of an impeller according to the invention;

Fig. 2

a section along line 2-2 through an impeller base body of the impeller according to the invention;

Fig. 3

a top view of the impeller base body in the direction of arrow A in Fig. 2 ;

Fig. 4

a top view of the impeller base body in the direction of arrow B in Fig. 2 ;

Fig. 5

a top view of a floor segment according to the invention for producing an impeller base of the impeller;

Fig. 6

a top view similar Fig. 4 with a first base segment inserted into the impeller base body;

Fig. 7

a cut along line 7-7 in Fig. 6 ;

Fig. 8

a cut similar Fig. 7 with welded floor segments;

Fig. 9

a top view of the impeller base body Fig. 6 with all welded-in floor segments to produce the impeller floor;

Fig. 10

a cut similar Fig. 2 through the impeller base body with welded-in bottom segments;

Fig. 11

a top view of the impeller bottom of the impeller in the direction of arrow C in Fig. 10 but with an additional support disk and

Fig. 12

a cut along line 12-12 in Fig. 11 through the finished impeller.

An in Fig. 1 Impeller shown as a whole and designated 10 for a fan or compressor, comprises an impeller cover 12 and an impeller base 14 opposite the impeller cover 12, between which there is an impeller interior 16, into which a gaseous medium enters through an inlet nozzle 22 formed on the impeller cover 12, is accelerated radially by impeller blades 24 arranged between the impeller cover 12 and the impeller base 14 and impeller channels formed between the impeller blades 24 and exits through radially outer outlet openings 26, the outlet openings 26 lying between an outer contour 32 of the impeller cover 12 and an outer contour 34 of the impeller base 14 , each of which runs at approximately the same radial distance from an axis of rotation 36 of the impeller 10.

The impeller 10 is assembled from an in Fig. 2 shown impeller base body 42, which is produced by milling from an oversized blank and includes the inlet nozzle 22 and the impeller cover 12, which extends from the inlet nozzle 22 radially outwards to the axis of rotation 36 up to the outer contour 32 ( Fig. 3 ).

Furthermore, a hub 44 is integrally formed on the impeller cover 12 and the inlet nozzle 22 opposite the inlet nozzle 22 and formed by milling the blank ( Fig. 2 , 4 ).

A connection between the impeller cover 12 and the hub 44 takes place in particular by impeller blades 24 designed as main impeller blades 46, which are also integrally formed on the impeller cover 12 and are formed by milling the blank ( Fig. 4 ).

These impeller main blades 46 then run on an inside 48 of the impeller cover from the inner regions 52 facing the inlet nozzle 22 and connecting the impeller cover 12 to the hub 44, the inlet-side ends 54 facing the inlet nozzle 22 ( Fig. 2 ), radially and azimuthally along the inside 48 of the impeller cover 12 up to outlet-side ends 56 which end close to or at a short distance from the outer contour 32 of the impeller cover.

The impeller main blades 46 are also integrally formed on the impeller cover 12 and are therefore part of the impeller base body 42.

To stabilize the area between the inlet nozzle 22 and the impeller cover 12, the impeller base body 42 is preferably also provided with a stiffening ring 62 that stabilizes a transition between them and is also provided with a radially outer cover stiffening ring 64 to stabilize the impeller cover 12, which is located over one of the inside 48 opposite outside 68 of the impeller cover 12 rises ( Fig. 2 , 3 ).

As in Fig. 4 shown, two types of impeller blades 24 are preferably provided in the illustrated embodiment, namely between the impeller main blades 46, the inner regions 52 of which are connected to the inlet nozzle 22, the impeller cover 12 and the hub 44 are and which extend to their outlet ends 56 near the outer contour 32 of the impeller cover 12, intermediate impeller blades 72 are arranged, the inlet ends 74 of which are arranged at a distance from the hub 44 and the outlet ends 76 of which are also close to the outer contour 32 of the impeller cover 12.

The intermediate impeller blades 72 are also integrally formed on the impeller cover 12 and rise from the inside 48, as in Fig. 4 shown, whereby the intermediate impeller blades 72 are also produced by milling a blank.

To form the impeller base 14, as in Fig. 5 shown, bottom segments 82 are provided, which are cut out of a piece of flat material, for example by wire erosion, and have a circumferential outer contour 84 forming an arcuate portion of the outer contour 34 of the impeller bottom 14, opposing main blade connection contours 86 and 88 running from the circumferential outer contour 84 to the hub 44, and a have hub connection contour 92 lying between the main blade connection contours 86 and 88.

Furthermore, between the main blade connection contours 86 and 88 there is a U-shaped groove extending radially inward starting from the circumferential outer contour 84, the U-shaped groove edges of which form intermediate blade connection contours 96, 97, 98.

These floor segments 82 are, as in Fig. 6 shown, inserted between successive impeller main blades 46 in the direction of rotation, such that, as again clearly shown in Fig. 7 shown, the respective bottom segment 82 with its main blade connection contours 86 and 88 rests on comb regions 104 of the main impeller blades 46, which adjoin an upper edge 102 of the main impeller blades 46 facing away from the impeller cover 12, namely on the mutually facing longitudinal sides 106 and 108 of the comb regions 104.

Furthermore, the intermediate blade connection contours 96 and 98 also lie on upper edges 112 of the intermediate impeller blades 72 adjacent comb regions 114, namely their longitudinal sides 116 and 118 facing away from one another.

The bottom segments 82 are preferably inserted in such a way that an outside 122 of the bottom segments 82 facing away from the impeller interior 16 is essentially aligned with the upper edges 102 and 112 of the impeller main blades 46 and the impeller intermediate blades 72.

In addition, the hub connection contour 92 rests on a peripheral side 124 of the hub 44.

The respective bottom segment 82 is fixed in the area of the main blade outer contours 86 and 88 and the intermediate blade connection contours 96, 97 and 98 first by welding points and then continuous welding takes place along the main blade outer contours 86 and 88 and the intermediate blade connection contours 96, 97 and 98 with the respective long sides 106 and 108 as well as 116 and 118 of the respective comb areas 104 and 114 as well as the hub connection contour 92 with the peripheral side 124 of the hub 44 by so-called I-weld seams 126 ( Fig. 7 , 8th ).

As in Fig. 8 and 9 shown, the floor segments 82 are preferably inserted sequentially until all floor segments 82 are inserted.

After all floor segments 82 have been welded in, there is an application of material in the area of the weld seams 126, which protrudes beyond the outside 122 of the floor segments 82.

To eliminate the material application, the unit consisting of the impeller base body 42 and the welded-in base segments 82 is over-twisted in the area of the outside 122 of the base segments 82 to produce a flat surface 132, which extends over the outer sides 122 of the base segments 82 and the upper edges 102 and 112 of the impeller main blades 46 and the intermediate impeller blades 72 and a support surface 134 of the hub 44, as in Fig. 10 shown, and then done on this plane surface, as in Fig. 11 and Fig. 12 shown, a placement of a support disk 142, which rests both on the support surface 134 of the hub 44 and on the outer sides 122 of the bottom segments 82 and possibly the upper edges 102 and 112 of the main impeller blades 46 and the intermediate impeller blades 72 and is flush with them.

The support disk 142 extends from an annular surface 144 that delimits the bearing surface 134 of the hub 44 radially on the inside in the radial direction to the axis of rotation 36 into an annular area 146 of the outside 122 of the impeller base 14, the annular area 146 being 0.5 times the Radial distance of the outer contour 34 of the impeller base 14 extends up to 0.7 times the same.

The support disk 142 preferably has an outer contour 148, which is welded to the impeller base 14 by means of a fillet weld 152.

Furthermore, an inner contour 154 of the support disk 142 is welded to the annular surface 144, preferably also by means of an I-seam.

In the impeller according to the invention, the impeller base body 42 as well as the base segments 82 are preferably made of high-strength and corrosion-resistant metallic materials, for example grade 5 titanium and/or high-strength, rust-free martensitic stainless steels.

The welding of the floor segments 82 is carried out in particular by a welding process starting from the outside of the floor segments 82, so that there is no need for welding in the impeller interior, preferably by laser beam welding without additional material or electron beam welding, which is possible because the floor segments 82 have a small gap tolerance, for example smaller than 0.2 mm, so that I-seams made in a simple manner from the outside 122 of the base segments 82 along the main blade connection contours 86 and 88 and the intermediate blade connection contours 96 and 98 as well as the hub connection contour 92 and the peripheral side 124 of the Hub 44 can be realized.

Preferably, after welding the base segments 82 into the impeller base body 42, a heat treatment is carried out, whereby residual welding stresses are reduced and thus defined mechanical properties are achieved, especially if the material for producing the impeller base body 42 and the base segments 82 is a rust-free martensitic stainless steel.

Finally, the impeller is pickled to remove welding tarnish and scale resulting from heat treatment and to improve corrosion resistance.

Claims (17)

1. Impeller (10) for a fan or a compressor, wherein the impeller (10) comprises an impeller base body (42) comprising an impeller cover (12) and impeller blades (24) integrally formed on the impeller cover (12), wherein an impeller bottom (14) is formed on the impeller base body (42) by welding the impeller bottom (14) to the impeller base body (42), characterized in that the impeller base (14) comprises a plurality of bottom segments (82) welded to the impeller base body (42).
2. Impeller according to claim 1, characterized in that the impeller base body (42) comprises impeller blades (24) extending between the impeller cover (12) and the impeller bottom (14) to exit openings (26) of the impeller (10).
3. Impeller according to claim 1 or 2, characterized in that the impeller base body (42) comprises a hub (44), which in particular is integrally formed thereon, in that in particular the impeller base body (42) has as impeller blades (24) impeller main blades (46) which are connected to the hub (44), in particular in the region of their inlet ends with the hub (44) and extending from these to outlet ends (56) on the outlet side, in that the impeller base body (42) in particular has as impeller blades (24) intermediate impeller blades (72) which are located between the impeller main blades (46) and, starting from inlet-side ends (74) arranged at a radial distance from the hub (44), extend as far as outlet-side ends (76).
4. Impeller according to one of the preceding claims, characterized in that the impeller base body (42) has an inlet nozzle (22) arranged on the impeller cover (12) , in that in particular the inlet nozzle (22) is integrally formed on the impeller cover (12).
5. Impeller according to one of the preceding claims, characterized in that the bottom segments (82) forming the impeller bottom (14) extend in each case between two mutually adjacent impeller main blades (46), in that in particular each of the bottom segments (82) is formed by a blank part of flat material which has main blade connection contours (86, 88) adjoining the impeller main blades (46) in comb regions (104), in that in particular each bottom segment (82) is welded along main blade connection contours (86, 88) to the comb region (104) of the impeller main blades (46).
6. Impeller according to one of the preceding claims, characterized in that the bottom segments (82) forming the impeller bottom (14) each extend between two adjacent impeller main blades (46) and the at least one intermediate impeller blade (72) located between the impeller main blades (46).
7. An impeller according to any one of the preceding claims, characterized in that each of the bottom segments (82) is formed by a blank of flat material having main blade connection contours (86, 88) adjacent the impeller main blades (46) in comb regions (104) and intermediate blade connection contours (96, 98) adjacent a comb region (114) of the at least one intermediate impeller blade (72), that in particular each bottom segment (82) is welded along main blade connection contours (86, 88) to the comb region (104) of the impeller main blades (46) and along the intermediate blade connection contours (96, 98) to the comb region (114) of the at least one intermediate impeller blade (72), and/or in that in particular the bottom segment (82) is welded along a hub connection contour (92) to a circumferential region (124) of the hub (44) extending between the impeller main blades (46).
8. Impeller according to any one of claims 5 to 7, characterized in that the bottom segments (82) are connected by an I-seam to the comb regions (104) of the impeller main blades (46) and the at least one intermediate impeller blade (72).
9. Impeller according to any one of claims 3 to 8, characterized in that the impeller (10) has a support disc (142) stabilizing the impeller bottom (14) in the region around the hub (44).
10. Impeller according to one of the preceding claims, characterized in that the impeller base body (42) has a stiffening ring (64) integrally formed on an outlet-side edge region of the impeller cover (12), in that, in particular, the stiffening ring (64) is integrally formed in one piece on the impeller base body (42).
11. A method of manufacturing an impeller (10) for a fan or a compressor, characterized in that an impeller base body (42) comprising an impeller cover (12) and impeller blades (24) integrally formed on the impeller cover (12) is manufactured by milling a blank, and that an impeller bottom (14) is fixed to the impeller base body (42) by welding a plurality of bottom segments (82) to the impeller base body (42).
12. Method according to claim 11, characterized in that impeller main blades (46) are formed on the impeller base body (42) by milling, the inlet-side ends (54) of which blades are attached in particular to a hub (44) of the impeller base body (42) and which extend as far as outlet-side ends (56), in that intermediate impeller blades (72) are formed in particular on the impeller base body (42) by milling, which intermediate impeller blades (72) extend from an inlet-side end (74) arranged at a distance from the hub (44) to an outlet-side end (76).
13. Method according to one of the claims 11 or 12, characterized in that the bottom segments (82) are inserted between mutually adjacent impeller main blades (46), in that in particular the bottom segments (82) are welded to comb regions (104) of the impeller main blades (46), in that in particular starting with a bottom segment (82) the bottom segments (82) are welded to the impeller base body (42), and/or in that, in particular, the bottom segments (82) are fixed to the comb regions (104) of the impeller main blades (46) by weld tack points before welding them in, in that, in particular, the bottom segments (82) are welded to the impeller main blades (46) with a continuous weld seam along their main blade connection contours (86, 88).
14. A method according to any one of claims 11 to 13, characterized in that the bottom segments (82) are inserted between adjacent impeller main blades (46) and at least one intermediate impeller blade (72) located between said impeller main blades (46), in that in particular the bottom segments (82) are welded to comb regions (104) of the impeller main blades (46) and to a comb region (114) of the at least one intermediate impeller blade (72) located between the impeller main blades (46), in that in particular starting with a bottom segment (82), the bottom segments (82) are welded to the impeller main body (42), and/or in that, in particular, the bottom segments (82) are fixed by weld spots to the ridge regions of the impeller main blades (46) and the intermediate impeller blade (72) before welding them in, and/or in that, in particular, the bottom segments (82) are welded with a continuous weld seam along their main blade connection contours (86, 88) to the impeller main blades (46) and intermediate blade connection contours (96, 98) are welded to the intermediate blade (72), and/or in that in particular the bottom segments (82) are welded to the impeller base body (42) by I-seams with the comb regions (104, 114) of the impeller main blades (46) and possibly of the intermediate impeller blade (72), and/or in that in particular the bottom segments (82) are produced from a flat material by wire erosion.
15. Method of any one of claims 11 to 14, characterized in that the impeller base body (42) with the welded-in bottom segments (82) is machined by turning over an outer surface (122) of the impeller bottom (14) to achieve a flat surface (132).
16. Method according to one of the claims 11 to 15, characterized in that a supporting disc (142) is placed on the impeller bottom (14) and connected thereto, in that in particular the supporting disc (142) is connected in its outer contour (148) to the impeller bottom (14), and/or in that in particular the supporting disc (142) is connected to the hub (44) with its inner contour surrounding the hub (44).
17. Method according to one of the claims 11 to 16, characterized in that an inlet nozzle (22) is arranged on the impeller base body (42) in the region of the impeller cover (12), in that in particular the inlet nozzle (22) is formed in the course of milling the blank for the impeller base body (42), and/or in that in particular a hub (44) of the impeller (10) is arranged on the impeller base body (42), and in that in particular the hub (44) is formed in the course of the milling of the blank for the impeller basic body (42), and/or in that in particular a cover stiffening ring (64) is arranged on the impeller basic body in an outlet-side region of the impeller cover (12), in that in particular the cover stiffening ring (64) is formed in the course of the milling of the blank for the impeller basic body (42).

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