Composite francis turbine wheel

FIELD: engines and pumps.

SUBSTANCE: proposed Francis turbine wheel comprises at least two wheel segments 12, 14 that can be jointed together along their opposed surface sections 16, 16a, 18, 18a to make composite wheel with top rim 28, bottom rim 30 and multiple vanes 32 running between said rims and secured thereto. Said opposed surface sections 16, 16a, 18, 18a are arranged solely along top and bottom rim segments. Note that opposed surface sections 16, 16a, 18, 18a of wheel segments 12, 14 are arranged between apart from adjacent vanes. Proposed wheel has central axis. Top rim has central round bore. Opposed surface sections 16, 16a of top rim, if seen from above, run from central bore, radially offset from central axis.

EFFECT: higher reliability and longer life.

7 cl, 2 dwg

 

The present invention relates to a work wheels for Francis turbines and, in particular, to composite the impeller to the turbine Francis.

Impellers for Francis turbines contain upper rim, a bottom rim and a multitude of turbine blades passing between the upper rim and lower rim. An example of such impeller disclosed in the publication DE 648174. In the manufacture of blades usually are fixed on the upper rim and the lower rim by welding. When the diameter exceeds 5 meters, for example, it is known separation of the impeller of the turbine in two segments, separated from each other by a plane passing along the axis of the impeller so as to provide the transportation of the impeller from the manufacturing site to the construction site of the dam. This radial plane cuts through the upper rim, a lower rim and some areas of blades.

At the site of the dam split segments of the impeller are collected by execution of welded joints in the upper rim, a lower rim and cut the blades. Welding blades requires great care due to the loads that should be applied to the blades during operation of the turbine. These welded connections typically perform filler metal-based material CA-6NM, which is an alloy of iron-chromium-Nickel-molybdenum, harden eleswarapu heat treatment. During the post-weld heat treatment of welded joints are susceptible to cracking, which requires re-processing of the welded connection up until there will be no cracks in the joints.

Accordingly would benefit from any improvements in the manufacture of composite impeller for Francis turbines, which would not lead to welded joints in the blades of the impeller and potential cracking of joints blades during post weld heat treatment.

The present invention relates to compound the impeller to the turbine Francis, containing at least two segments of the impeller, designed to connect together at their opposite surface areas for the formation of composite impeller having a top rim, a bottom rim and a variety of blades passing between the upper rim and lower rim and attached to them. The improvement of the present invention refers to the opposite surface areas of the segments of the impeller, which are located only along sections of the upper rim and lower sections of the rim and to the opposite surface areas of the segments of the impeller, which are located between adjacent composite blades of the impeller and are about them. Since the opposite surface sites are located only along sections of the upper rim and parts of the lower rim, none of the blades is cut, whereby is eliminated the welding of the blades in the process of formation of a compound of the impeller at the site of the dam. Accordingly, the composite impeller has no welded joints formed in the blades, which are heavily stressed working parts of the impeller.

In one embodiment of the invention the segments of the impeller are connected together by welded connection. This welding can be a partial receipt of weld penetration of the base metal. In an alternative embodiment, the upper rim can be connected mechanical fastening means such as bolts and nuts. Additionally it is envisaged that the weld material used in welded joints, is a material which does not require post weld heat treatment. Such material is, for example, welded material E309L.

Thus, according to the object of the present invention created a composite impeller for Francis turbines, containing at least two segments of the impeller, made with the possibility of connection together they protivole the relevant surface areas for the formation of a compound of the impeller, having a top rim, a bottom rim and a variety of blades passing between the upper rim and lower rim and attached thereto, while the opposite surface areas of the segments of the impeller are located only along sections of the upper rim and parts of the lower rim and the opposing surface areas of the segments of the impeller are located between adjacent composite blades of the impeller and are separated from them, and the composite impeller has a Central axis, and the upper rim has a Central opening round shape, while the opposite surface plots plots of the upper rim, when viewed from above, are from the Central hole with a radial offset from the Central axis.

Preferably, the segments of the impeller are connected together by welded connection.

Preferably, the weld material used in welded connection, does not require post weld heat treatment.

Preferably, the welded material contains welded material E309L.

Preferably, the opposing surface areas are located midway between adjacent blades.

Preferably, the opposing surface areas are located midway between adjacent blades.

Preferably, each set of blades and EET opposite surface contour, and the opposing surface areas, which are areas along the upper rim and parts of the lower rim, continue along the contour corresponding to the contour of the blade, adjacent the upper rim and lower rim.

As a result, the design according to the present invention provides for receiving the impeller, with increased reliability and durability.

For a better understanding of the nature and purposes of the present invention further provides a more detailed description of the present invention with reference to the attached schematic drawings, on which:

Figure 1 is a top view of a composite impeller for use in a Francis turbine;

Figure 2 is a side view of a composite impeller 1.

The present invention relates to the working wheels of a Francis turbine for use in turbines and, in particular, it relates to composite the impeller 10 type Francis. Split impeller 10, is shown in figures 1 and 2, contains two segments 12 and 14 of the impeller. In the drawings, the two segments 12 and 14 of the impeller shown separated from each other. In the manufacture in the production area segments are usually processed, touching each other. Also, on the site of the dam segments 12 and 14 will be in contact with each other when the welded connection m is waiting for the segments for the formation of composite impeller.

In accordance with the present invention these segments 12 and 14 of the impeller adapted to connect together along the opposite surface sections 16 and 16A of the upper rim and an opposite surface sections 18 and 18a of the lower rim for the formation of composite impeller. It should be noted that in the drawings is shown a split impeller 10 of the two segments, although the impeller can be cut into more than two segments. However, the number of segments should be minimized, because each segment requires more Assembly at the construction site of the dam. It is obvious that the number of selected segments is determined by the size of the impeller and restrictions as determined by the transportation segments of the impeller on the way of transportation, delivered from the manufacturing site to the construction site of the dam.

Composite impeller includes an upper rim 28, the lower rim 30 and the many blades 32 passing between the upper rim 28 and the lower rim 30 and is attached thereto.

Opposite surface sections 16, 16A and 18, 18a of the segments 12, 14 of the impeller are located only along sections 34 of the upper rim sections 28 and 36 of the lower rim 30. Opposite surface sections 16, 16A and 18, 18a of the segments 12 and 14 of the impeller is located in the middle between adjacent blades 32 and 32b of the impeller 10 and are separated from them. Each of the blades 32 shown in the drawings, the curved along opposite surfaces 50, 52 with the specified path. Opposite surface sections 16, 16A (see Figure 2) and 18, 18a also continues along paths similar to the contour of the blades adjacent the upper rim 28 and adjacent the lower rim 30. Preferably, the opposing surface sections 16, 16A and 18, 18a are located midway between adjacent blades 32A, 32b, that is, where the blades 32A, 32b meet with the upper rim 28 and the lower rim 30. This puts a welded joint at the optimal distance from the most heavily loaded blades.

As better shown in figure 1, the composite impeller 10 and the resulting composite impeller has a Central axis 60 and the upper rim 28 having a Central core opening 62. Opposite surface sections 16, 16A of the upper rim 28, as shown in the top view Figure 1, extend from the Central hole 62 with a radial offset from the Central axis 60.

The segments 12 and 14 of the impeller are joined together by a welded joint, which is located between the opposite surface sections 16, 16A and 18, 18a. Preferably the weld material used in welded joints, does not require post weld heat treatment of welded and contains material E309L. Given the welding process can contain partial receipt of weld penetration of the base metal.

Although the invention has been described with reference to a specific version of its realization, the person skilled in the art will understand that the invention can be implemented in practice with the changes that are included in the scope of the attached claims.

1. Composite impeller for Francis turbines, containing at least two segments of the impeller, designed to connect together at their opposite surface areas for the formation of composite impeller having a top rim, a bottom rim and a variety of blades passing between the upper rim and lower rim and attached thereto, while the opposite surface areas of the segments of the impeller are located only along sections of the upper rim and parts of the lower rim, and these opposite surface areas of the segments of the impeller are located between adjacent composite blades of the impeller and are separated from them, and the composite impeller has the Central axis, and the upper rim has a Central opening round shape, while the opposite surface plots plots of the upper rim, when viewed from above, are from the Central hole with a radial offset from the Central axis.

2. The impeller according to claim 1, in which the segments of the impeller connection is received together with a welded connection.

3. The impeller according to claim 2, in which the weld material used in welded connection, does not require post weld heat treatment.

4. The impeller according to claim 3, in which the welded material contains welded material E309L.

5. The impeller according to claim 2, in which the opposite surface sites are located midway between adjacent blades.

6. The impeller according to claim 1, in which the opposite surface sites are located midway between adjacent blades.

7. The impeller according to claim 1, in which each set of blades is opposite the surface contour, and the opposite surface areas, which are areas along the upper rim and parts of the lower rim, continue along the contour corresponding to the contour of the blade, adjacent the upper rim and lower rim.



 

Same patents:

FIELD: turbine engineering.

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EFFECT: enhanced efficiency and reliability.

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Turbine // 2263814

FIELD: mechanical engineering; turbines.

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FIELD: engines and pumps.

SUBSTANCE: proposed Francis turbine wheel comprises at least two wheel segments 12, 14 that can be jointed together along their opposed surface sections 16, 16a, 18, 18a to make composite wheel with top rim 28, bottom rim 30 and multiple vanes 32 running between said rims and secured thereto. Said opposed surface sections 16, 16a, 18, 18a are arranged solely along top and bottom rim segments. Note that opposed surface sections 16, 16a, 18, 18a of wheel segments 12, 14 are arranged between apart from adjacent vanes. Proposed wheel has central axis. Top rim has central round bore. Opposed surface sections 16, 16a of top rim, if seen from above, run from central bore, radially offset from central axis.

EFFECT: higher reliability and longer life.

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SUBSTANCE: hydraulic machine comprises an inner and an outer separating circular hydrodynamic seals 8 and 9, arranged into each or one of cavities around an impeller 2 - between the impeller 2 and a cover 5 and between the impeller 2 and a foundation ring 6. The outer separating seal 8 is located in the area of the peripheral zone of the impeller 2, and the inner one 9 - between the outer separating seal 8 and a seal 7, which limits leaks into a suction pipe. Two rings 10 and 11, which form the inner separating seal 9, have a Z-shaped or an angular profile in the cross section and are installed so that free shelves of their cross sections cover each other. Each cavity, where separating seals 8 and 9 are installed, is separated into two chambers 12 and 14. The external chamber 14 is equipped with an input 17 for compressed gas supply.

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1 dwg

FIELD: machine building.

SUBSTANCE: impeller of Francis type includes rim 1 with rotation symmetry about rotation axis Z of impeller and bent blades 21, 22, which are rigidly attached to rim 1, each of which includes external peripheral edge 212, 222 and internal central edge 211, 221. Connection points B21, B22 of rim 1 with internal central edges 211, 221 of blades 21, 22 are located on one and the same circle C20 centred relative to above mentioned axis Z. Connection points A21, A22 of rim 1 with external peripheral edges 212, 222 of blades 21, 22 are located at least on two different circles C21, C22 centred relative to axis Z.

EFFECT: reduction of the cost of composite elements of devices owing to limiting their dimensions by reducing the action on them of radial stresses under unsteady conditions.

11 cl, 4 dwg

FIELD: machine building.

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EFFECT: compact design, high efficiency and lower noise.

7 cl, 5 dwg

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