WO2019239255A1

WO2019239255A1 - Apparatus for the working of the sliding surfaces of a turbine shaft

Info

Publication number: WO2019239255A1
Application number: PCT/IB2019/054671
Authority: WO
Inventors: Vladimir NEMICH
Original assignee: Nuova Simat S.R.L.
Priority date: 2018-06-12
Filing date: 2019-06-05
Publication date: 2019-12-19
Also published as: IT201800006235A1

Abstract

The present invention relates to a device for the recovery of the sliding surfaces of a shaft, for example of a turbine. It is to be meant that the invention can be applied even for other machines such as for example compressors, pumps and other energy generation or consumption machines.

Description

APPARATUS FOR THE WORKING OF THE SLIDING SURFACES OF A

TURBINE SHAFT

DESCRIPTION

Background

It is well known that, with use, it results to be necessary to restore the sliding surfaces on the shaft of the hydrostatic and hydrodynamic shoes, caused by the seizing due to ruptures of the lubrication system or an anomalous consumption of the components of the same, circumstances which lead to localized damages on the mobile shoe installed on the turbine casing and on the sliding surface of the turbine itself.

The damages of the shoes can be easily eliminated as the hydrostatic shoes can be disassembled without difficulty from their seat, and then, if required, their replacement is possible. On the contrary, the damages to the sliding surface of the shaft itself are much more critical, as they involve a pressure drop too and sometimes a loss in functionality, but the turbine shaft cannot be so easily replaced due to its high cost.

For this reason, a working thereof at the machine tools is requested. However, in order to perform such working on traditional machine tools, it is required that the shaft with its staking is disassembled, loaded on an exceptional transport, transported, discharged near a lathe able to perform the required working, worked, re-loaded on the exceptional transport, transported again to the production site, discharged and installed at its operating seat. It results clear that time and complexities of the above-mentioned procedures increase depending upon the installed power and then the sizes of the turbine shaft.

The cost of repairs of a bearing seat is due partially to the above-mentioned procedures and partially to the machine downtime (missed production). The machine downtime increases exponentially depending upon the size of the turbine itself considering that the time for movements increases more and more.

From this it is extremely evident that a problem solution allowing an intervention on site would lead to tangible advantages, well quantifiable for the final customer. There are in the art some apparatuses allowing, within certain limits, some workings directly on the shaft. However, all currently known apparatuses, often cannot be used“in loco” due to their sizes, often too big for an effective use.

For example, the document WO2013/167293 describes a turning machine which can be used in working components having heavy weight and sizes which, due to its specific embodiment, moreover characterized by a transmission system of direct type, involves a considerable overall dimensions and obstruction by the engine member in manoeuvring the rotating element. This does not allow to perform accurate workings by means of fine and controlled motions of the crankshaft.

Moreover, all known apparatuses, implement the shaft turning by having as reference surface“to be copied” the same surface of the shaft. Then, often it happens that the working copies even the surface defects and/or the damages existing on the surface portion used as reference for turning.

Technical problem solved by the invention

The object of the present invention is to solve the problems left unsolved by the known art, by providing an apparatus for the working of the sliding surfaces of a turbine shaft, as defined in the independent claim No. 1.

Additional features of the present invention are defined in the corresponding dependent claims. The present invention involves several and evident advantages with respect to the known art.

The main advantage is that the present invention allows to perform the working, without having to disassemble the shaft from the lower casing of the turbine and without disassembling the power transmission flanges between generator and user.

Moreover, the apparatus according to the present invention, does not use the same shaft surface as reference for turning. Consequently, the working cannot suffer from the defects due to possible damages already existing on the surface On the contrary, in each case, the ground surface will be substantially like new, and precise within the imposed tolerance limits.

Moreover, an apparatus according to the present invention, allows a preliminary setting and/or a continuous adjustment of the grinding mechanism, so that the operator can set a priori the type of working to be performed and, consequently, to obtain the wished result, with the precision suitable to the type of working, and without dragging in the working possible defects already existing on the shaft surface.

The radial overall dimensions of an apparatus according to the invention are further much smaller than the known art and then they allow to work the shaft surfaces by disassembling only the hydrodynamic support, without having to disassemble the shaft from the power transmission flanges.

Moreover, the apparatus according to the invention, thanks to its direct transmission mechanism by means of the belt, even lighter than the indirect transmission systems of the known art, allows to obtain higher transmitted rotation speed, by exploiting less mechanical energy transmitted by the power transmission shaft.

An additional advantage of the apparatus according to the invention is to be influenced in a much less marked way by possible vibrations imposed by the crankshaft. The elastic belt which in fact interposes between the crankshaft and the transmission shaft attenuates for most part the vibrations derived from the stresses of the crankshaft.

Therefore, another advantage of the apparatus of the invention is that of allowing a greater working precision.

A still additional advantage of the apparatus according to the invention is to allow greater application flexibility, as it performs an outdistancing between the axis of the member imparting the rotative force and the axis of the member to be rotated.

Other advantages, together with the features and the use modes of the present invention, will result evident from the following detailed description of preferred embodiments thereof, shown by way of example and not for limitative purposes.

Brief description of figures

Hereinafter in this description the drawings shown in the enclosed figures will be referred to, wherein:

• figure 1 is an overall view of an apparatus according to the present invention;

• figure 2 is a side view of the apparatus of figure 1 ;

• figure 3 is a view in longitudinal section of the apparatus of figure 1 ;

• figure 4 is a view in cross section of the apparatus taken according to the line A-A of figure 2; and

• figure 5 is a more detailed view of an apparatus according to the present invention. Detailed description of preferred embodiments

The present invention will be described by making reference to the above- mentioned figures.

In particular, by making firstly reference to figure 1 , this shows an axonometric view of an apparatus 1 according to the present invention. According to a more general definition of the invention, an apparatus 1 for the working of the sliding surfaces 101 of a shaft 100 of a turbine, first of all comprises a fixed frame 2.

The fixed frame 2 has to be fixed to the shaft 100 and for this purpose corresponding fixing means 300 is provided, for example chains for fixing on the shaft 100 implemented according to what already known in the field.

The fixed frame 2 carries supporting and guiding means 4, connected thereto, as it will be better detailed hereinafter.

Moreover, such supporting and guiding means 4 carries a movable frame 5, indeed mounted so as to be able to move with respect to the supporting and guiding means and to said fixed frame 2 and, consequently with respect to the shaft 100 to be worked.

The movable frame 5, in turn, carries a rotating ring 51 apt to be positioned, upon use, around the shaft 100 to be worked. The rotating ring 51 bears the machining tool 52 which, during the rotation of the rotating ring 51 performs a mechanical working of the surface 101 of the shaft 100.

Advantageously, the supporting and guiding means 4 further comprises its own adjustment means 41 , the setting thereof allows to determine a predefined trajectory of the movable frame 5 with respect to the fixed frame 2 and to the shaft 100, during its movement.

This, advantageously, lastly allows to set and/or control the motion of the machining tool and, then, allows to determine exactly the type of working to be performed.

For example, the trajectory of the movable frame 5 (and then of the machining tool 52), could be determined so as not to be exactly parallel to the axis of the shaft 100. This can be advantageous for example when there has been an anomalous consumption of the shaft surface, therefore not only the initial roundness has been lost, but also the resulting axis has modified its position, or the tilting and then it is necessary to work the surface so as to recover the initial geometries. Moreover, the possibility to determine such trajectory independently from the surface of the shaft 100 allows to perform a working the result thereof does not depend upon the precision and/or quality of the surface 101 of the shaft. In fact, as already said, such surface itself could be damaged and have the defects. Should the working take as reference such surface, the defects would be reproduced during grinding on the surface portions involved by the machining tool.

On the contrary, the reference for the working, according to the invention, is exactly the trajectory of the movable frame 5, which is determined wholly independently from the surface to be ground.

According to the embodiment illustrated in the figures, the supporting and guiding means 4 comprises first moving means 41 apt to rotate said rotating ring 51.

Such first moving means 41 comprises a power transmission shaft 42.

This is mounted idly on the fixed frame 2, and carries a dragging member 43 slidingly mounted thereon.

An outer engine can be provided for actuating the power transmission shaft 42.

The rotating ring 51 can be assembled so as to slide on sliding shoes 31 , preferably made of bronze or other material having low friction coefficient, carried by the movable frame 5. Alternatively, the shoes can be replaced by one or more wheels.

The ring 51 is then rotated through a belt drive 44 made between the rotating ring 51 and the dragging member 43, in particular a pulley.

Alternatively to the belt, the use of a transmission chain, positioned between toothed wheels, can be of course provided.

Moreover, the supporting and guiding means 4 comprises second moving means 45 apt to translate the movable frame 5 along a direction substantially parallel to that of the shaft 100. Under the term“substantially parallel” one does wish to mean herein“exactly parallel”. In fact, as it will be seen, according to the present invention such direction can advantageously be varied and then set as not parallel to the axis of the shaft 100. What one wishes to mean is that the possibility of varying the translation direction is limited to a tilting of some degrees with respect to the axis of the shaft. The maximum value for the tilting angle is limited only by the constructive geometry of the machine (height, length and length of the records).

Generally, according to the invention, a tilting angle even higher than 30° is possible. Preferably, a tilting can be provided in any direction (yawing, pitch or rolling) from a minimum of 0° to a maximum of 15° or more.

In particular, according to the embodiment shown in the figures the second moving means 45 comprises a sliding shaft 46 connected to the fixed frame 2 and a sliding member47 is slidingly mounted on the sliding shaft 46.

A second external actuator, for example a second engine, is provided to translate the sliding member along the sliding shaft 46.

According to the preferred embodiment, shown in the figures, the fixed frame 2 comprises two frame portions 21 , 22, each one comprising its own means 3 for fixing to the shaft 100. The fixing means can be, as said, of the chain type.

However, it is to be meant that the presence of two distinct frame portions is only a preferred, but certainly not necessary, feature. The apparatus could provide one single frame portion, on one of the sides and both shafts, both the power transmission one and the sliding one, cantilever mounted on the fixed frame.

According to the preferred embodiment, providing two frame portions 21 , 22, these are mounted opposite with respect to the movable frame 5, thus defining a working area, within thereof the movable frame 5 can slide.

By making reference also to figure 5, as already said, the trajectory followed by the movable frame 5 during the working can be, according to the invention, controlled and adjusted.

To this purpose, according to the preferred embodiment, the adjustment means 41 comprises a mechanism for adjusting the direction of the power transmission shaft 42 and/or of the sliding shaft 46.

In this way, the direction D, D’ of the power transmission shaft 42 and/or of the sliding shaft 46 determines the predefined trajectory of the movable frame 5 with respect to the fixed frame 2 and to the shaft 100. By pure way of example, the adjustment mechanism can be of the micrometric screw type, as exemplified in figure 5 and it allows to adjust the direction on both portions of fixed frame 21 , 22 and, on each one, in two directions orthogonal therebetween, so as to be able to orient as wished the power transmission shaft 42 and/or of the sliding shaft 46, as schematized with the arrows in figure 5.

The present invention has been sofar described with reference to preferred embodiments thereof. It is to be meant that each one of the technical solutions implemented in the preferred embodiments, herein described by way of example, can advantageously be combined, differently from what described, with the others, to create additional embodiments, belonging to the same inventive core and however all within the protective scope of the herebelow reported claims.

Claims

1. Apparatus (1) for the working of the sliding surfaces (101) of a shaft (100), in particular of a turbine, comprising:

- a fixed frame (2) comprising means (3) for fixing it to the shaft (100);

- supporting and guiding means (4), carried by said fixed frame (2);

- a movable frame (5), carried by said supporting and guiding means (4);

wherein said movable frame (5) comprises a rotating ring (51) apt to be positioned around said shaft (100) and bearing a machining tool (52) suitable for carrying out a mechanical working of the surface (101) during the rotation of said rotating ring

(51),

wherein said supporting and guiding means (4) comprises its own adjustment means apt to determine a predefined trajectory of said movable frame (5) with respect to said fixed frame (2) and to said shaft (100) during its movement, and wherein said rotating ring (51) is rotated by means of a belt drive (44) made between said rotating ring (51) and said dragging member (43).

2. Apparatus (1) according to claim 1 , wherein said supporting and guiding means (4) comprises first moving means (41) apt to rotate said rotating ring (51).

3. Apparatus (1) according to one of the preceding claims, wherein said first moving means (41) comprises a power transmission shaft (42) mounted idly on said fixed frame (2), and a dragging member (43) slidingly mounted on said power transmission shaft (42), said power transmission shaft (42) being apt to be moved by a first external actuator (150).

4. Apparatus (1) according to one of the preceding claims, wherein said supporting and guiding means (4) comprises second moving means (45) apt to translate said movable frame (5) along a direction substantially coinciding with that of the shaft

5. Apparatus (1) according to the previous claim, wherein said second moving means (45) comprises a sliding shaft (46) connected to said fixed frame (2), and a sliding member (47) slidingly mounted on said sliding shaft (46), said sliding member (47) being apt to be moved by a second external actuator (151).

6. Apparatus (1) according to one of the preceding claims, wherein said fixed frame (2) comprises two frame portions (21 , 22), each one comprising its own means (3) for fixing to the shaft (100).

7. Apparatus (1) according to the previous claim, wherein said two frame portions (21 , 22), are mounted opposite with respect to the movable frame (5).

8. Apparatus (1) according to one of the preceding claims, wherein said movable frame (5) comprises a plurality of sliding pads (31) for said rotating ring (51).

9. Apparatus (1) according to any one of claims 3 to 8, wherein said adjustment means (41) comprises a mechanism for adjusting the direction of said power transmission shaft (42) and/or of said sliding shaft (46), the direction of said power transmission shaft (42) and/or of said sliding shaft (46) determining a predefined trajectory of said movable frame (5) with respect to said fixed frame (2) and to said shaft (100).

10. Apparatus (1) according to the previous claim, wherein said adjustment mechanism is of the micrometric screw type.