Francis turbine spiral turbine chamber

Abstract

Francis turbine spiral turbine chamber, which consists of several fixed guide columns (2) welded vertically to fixed rings (1), which in turn are welded to a spiral tube (5) consisting of individual segments (5.1), (5.2) and (5.3) which are welded together, and which spiral tube (5) is welded to a tangential tube (6), which in turn is welded to a connecting flange (7) and further additional elements such as the end flanges (8) and (9), the conical tube (10), the ribs (11) and (12), characterized in that the fixed guide columns (2) are constructed element by element from a plurality of separate parallel connected elements (2.1), (2.2) and (2.3), which terminate with the end elements (2.4) and (2.5), which are all connected vertically to the fixed rings (1) with welds (3) and to each other with welds (4) are welded to form the fixed guide columns (2) element by element.

Description

area of ​​technology

[0001] The spiral turbine chamber is a basic element of Francis turbines, which are widely used in hydroelectric power plants and pump-storage hydroelectric power plants equipped with Francis turbines as the main water unit. State of the art

[0002] Spiral turbine chambers are known in which fixed guide columns are located between two fixed rings (arc discs). These columns are monolithic metal elements that are welded to the two fixed rings along their front side, usually by electroslag welding, and along their contours by a girth weld. During primary production, after electroslag welding of the stationary guide columns to the stationary rings of the spiral turbine chamber, significant residual stresses and structural changes occur in the base material, caused by the intense heating during the welding process. The occurrence of internal stresses during operation can lead to microcracks and the destruction of one or more fixed guide columns. To prevent these negative effects, previously welded components are subjected to heat treatment and annealing.

[0003] Francis turbines for hydroelectric power plants are very often subject to operational wear and cracks on the stationary guide columns of the spiral turbine chamber. When these adverse effects occur, repair work is carried out by welding to restore the original shape. If the resulting cracks extend across the entire cross-section of the fixed guide column, complete restoration is not possible. In this case, the column must be removed by cutting it out and replaced with a new guide column of the same geometry and dimensions. Welding along the end faces of the new fixed guide column to the fixed rings is usually performed using electroslag welding, and along its contour using girth welding.The described design requires a method for repairing and replacing the stationary guide columns that is very close to the primary production process, but is very difficult to implement outside the factory with already welded stationary rings and stationary guide columns of the spiral turbine chamber.

[0004] When repairing already welded fixed guide columns on fixed rings of the spiral turbine chamber of a Francis turbine for a hydroelectric power plant, a "tempering" heat treatment is very difficult to perform. This requires the replacement of the entire spiral turbine chamber of the Francis turbine of the hydroelectric power plant in question. Technical nature of the utility model

[0005] The objective of the utility model is to create a spiral turbine chamber that limits the occurrence of internal stresses and microcracks, eliminates the need for tempering heat treatment, and facilitates on-site repair work without the need to replace the entire spiral turbine chamber.

[0006] This task is solved by a spiral turbine chamber of a Francis turbine, which consists of several fixed guide columns welded vertically to fixed rings, which in turn are welded to a spiral tube consisting of individual segments welded together.The spiral tube is welded to a tangential tube, which in turn is welded to a connecting flange and other additional elements, such as end flanges, a conical tube, and fins. Instead of the metallic monolithic fixed guide columns, there are element-based fixed guide columns between the two fixed discs. These fixed guide columns consist of a multitude of separate, parallel-connected flat elements with side surfaces, each shaped to form a continuous lateral envelope of the element-based fixed guide columns. Each subsequent element is welded both to the previously welded element of the fixed guide column and perpendicular to the fixed rings. The end elements of the element-based fixed guide columns each have rounded side surfaces and a smooth shell of the element-based fixed guide columns, which can be made, for example, from high-strength rolled steel sheet.

[0007] The spiral turbine chamber constructed in this way allows for the use of smaller welds, which, unlike electroslag welding, release less heat during their production, and the possibility of internal stresses and microcracks developing is reduced. Tempering heat treatment outside of factory conditions is also unnecessary or can be performed more easily for each weld individually if necessary. Improved operator accessibility makes repair work easier.

[0008] Another significant advantage is that a crack that occurs during operation in the element-by-element fixed guide columns only propagates within the individual element and does not spread to the other elements. For such a crack to develop in a new element, a new initial impact is required. In contrast, the resulting crack in the monolithic fixed guide column propagates much more easily across the entire cross-section. Due to the different construction of the two blank types, the element-by-element locking columns made of high-strength rolled steel sheet exhibit significantly higher tensile strength than the monolithic locking column.

[0009] The device of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant with element-wise fixed guide columns proposed here can be used both for the initial installation in the manufacture of new hydroelectric power plants, for the repair and replacement of monolithic fixed guide columns and for the replacement of the guide columns with new ones with changed geometry and / or changed number and / or changed position in order to improve the operating efficiency of the entire hydroelectric power plant. Explanation of the attached illustrations Fig. shows as an example an overall view in axonometric representation of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant. Fig. shows as an example a cross section S1-S1 of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant, in which a fixed ring and the cut fixed guide columns are visible. Fig. shows, as an example, a cross-section along the S2-S2 axis of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant, with the two cut-open fixed rings and the fixed guide columns located between them being visible. In Fig. An exemplary embodiment of welded stationary rings and stationary guide columns arranged therebetween of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant is shown. In Fig. As an example, a front view of welded stationary rings and stationary guide columns constructed element by element between them of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant is shown. Fig. shows an exemplary embodiment of a partial cross-section showing a portion of a fixed ring and a monolithic fixed guide column of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant. Fig. shows an exemplary embodiment of a partial cross-section showing a portion of a fixed ring and a fixed guide column constructed element by element from a plurality of separate flat elements, each element being welded to the fixed rings and the previous flat element of the element by element constructed fixed guide column of a spiral turbine chamber of a Francis turbine for a hydroelectric power plant. Exemplary implementation of the utility model

[0010] A Francis turbine spiral chamber for a hydroelectric power plant with element-wise fixed guide columns consists of several fixed guide columns 2, which in turn consist of a plurality of separate, parallel-connected flat steel elements 2.1, 2.2, 2.3 and terminate with end elements 2.4 and 2.5, the side surfaces of which are each shaped to form a continuous lateral envelope of the element-wise fixed guide columns 2, all of which are welded vertically to fixed rings 1 with weld seams 3 and welded together with weld seams 4. The fixed rings 1 are welded together to the spiral tube 5, which consists of separate segments 5.1, 5.2, and 5.3, and to the tangential tube 6, which in turn is welded to a connecting flange 7. The end elements 2.4 and 2.55 of the element-wise constructed fixed guide columns 2 each have rounded side surfaces and a smooth shell of the element-wise constructed fixed guide columns 2, which is made, for example, of high-strength rolled steel sheet. The Francis turbine spiral turbine chamber for a hydroelectric power plant with element-wise constructed stationary guide columns 2 comprises further additional elements, such as end flanges 8 and 9, a conical tube 10, and fins 11 and 12. The reference symbols of the technical features in the claims serve merely to improve the comprehensibility of the claims and have no limiting effect on the design of the elements designated by them.

Claims

[1] Francis turbine spiral turbine chamber, consisting of several fixed guide columns (2) welded vertically to fixed rings (1), which in turn are welded to a spiral tube (5) consisting of individual segments (5.1), (5.2) and (5.3) welded together, and which spiral tube (5) is welded to a tangential tube (6), which in turn is welded to a connecting flange (7) and other additional elements such as the end flanges (8) and (9), the conical tube (10), the fins (11) and (12), characterized by that the fixed guide columns (2) are constructed element by element from a plurality of separate parallel connected elements (2.1), (2.2) and (2.3), which terminate with the end elements (2.4) and (2.5), which are all welded perpendicularly to the fixed rings (1) with weld seams (3) and to each other with weld seams (4), so as to form the fixed guide columns (2) element by element. [2] Francis turbine spiral turbine chamber according to claim 1, characterized by that the elements (2.1), (2.2) and (2.3) have side surfaces which are each shaped in such a way that they form a continuous lateral surface of the stationary guide columns (2) constructed element by element. [3] Francis turbine spiral turbine chamber according to claim 1, characterized by that the end elements (2.4) and (2.5) are each shaped so that they form a rounded curve and a smooth shell of the end elements of the element-wise constructed stationary guide columns (2). [4] Francis turbine spiral turbine chamber according to claim 1, characterized by that the elements (2.1), (2.2) and (2.3) as well as the end elements (2.4) and (2.5) of the element-wise constructed stationary guide columns (2) consist of high-strength rolled steel sheet.

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