FR2878951A1 - Rotor alignment measuring method for electricity production machine, involves measuring lateral spacings between laser beam and inner borders of stator by emitting and measuring range of another laser beam up to inner borders of stator - Google Patents

Abstract

The method involves positioning a laser beam (3) within a stator to constitute a longitudinal reference axis. Lateral spacings between the laser beam (3) and inner borders of the stator forming diaphragm are measured by emitting another laser beam (5) in an elongated direction of the laser beam (3) and by measuring range of the beam (5) up to the inner borders of the stator. An independent claim is also included for a rotor centering measuring device.

Description

2878951 1

  The invention relates to means for measuring the centering of an electricity generating turbine rotor within its associated stator.

  A turbine is an assembly consisting of a rotating part (rotor) and a fixed part (stator).

  The rotor consists of a cylindrical shaft carrying a number of fins which constitute a set of wheels of different diameters.

  The stator, or body, is the very frame of the turbine and supports fixed vanes (diaphragms). It further has a series of bearings to support the rotor shaft.

  By diaphragms is meant discs disposed within the stator, perpendicular to the longitudinal axis of said stator. These discs are intended to carry the vanes which form partitions between the successive wheels of the rotor.

  The mass of a rotor being close to 200 tons, and the rotor typically rotating at 1500 rpm for diameters typically up to five meters, the centering is particularly important because a friction point between rotor and stator would produce overheating. and unacceptable vibrations, which can lead to stopping the turbine.

  To realize or control the centering of the rotor in its stator, there are different methods.

  Thus, US Pat. No. 5,517,491 (Bush et al.) Has proposed a rotor / stator centering analysis device in which a laser beam disposed longitudinally in the stator is used to create a reference serving as a centering reference. Radial spacing with respect to this reference laser beam is then measured at various points by optoelectronic means resting on the internal borders of the diaphragms.

  It is thus necessary to ensure that the optoelectronic means are well positioned so as to be permanently in mechanical contact with the internal borders. But such a positioning requires a relatively long implementation time (and during which the reference laser can further derive) and is otherwise complex 2878951 2 (so that it results in positioning errors, and therefore centering the rotor in its stator).

  Thus, the device proposed in document US Pat. No. 5,517,491, while providing some satisfaction, nevertheless remains of a reliability and an efficiency which it is desirable to improve and suggests that optical means coupled to a laser reference are of a rather complex implementation.

  US 5,727,327 (Wakabyashi et al) shows a device based on the use of a reference wire placed there also in longitudinal position in the stator. This time, a laser is used to measure the radial spacing existing between this longitudinal beam and the internal bearing surfaces of the various stator bearings.

  This device, a simple implementation of the ease of using a transverse laser to a wire (which must however adjust voltage in particular to reproduce the arrow of the rotor), however, remains of limited reliability.

  The object of the invention is to improve this existing technique by proposing a method and a device of improved accuracy and reliability, and of a faster implementation.

  This object is achieved according to the invention by means of a method for measuring the centering of a rotor in its stator within a turbine for the industrial production of electricity, the method comprising the placing of a laser beam within the stator to form a longitudinal reference axis of the measurement, the method further comprising a step of measuring different lateral spacings between the reference axis laser beam and the internal edges of the stator forming diaphragms, characterized in that the lateral spacings between the reference axis laser beam and the internal edges of the diaphragm stator are measured by emitting a second laser beam away from the reference axis laser beam and measuring the range of the laser beam. this second laser beam to each said internal rim of the stator forming a diaphragm.

  Some preferred, but non-limiting, aspects of the process according to the invention are the following: - in the same predefined reference system, a measurement of the position of the longitudinal laser beam forming reference axis at the right of each internal rim under consideration of the stator is carried out forming a diaphragm, and this measurement is associated with the lateral spacing measurement between the diaphragm inner rim and the reference axis laser beam to obtain a measurement of positioning of the diaphragm inner rim expressed in said predefined reference frame; a preliminary step of measuring the positioning of a central axis of the rotor shaft is carried out and the positioning of the laser forming the reference axis is compared with that position of the axis of the rotor shaft; so that the lateral spacing measurement results are expressed with respect to the central axis of the rotor shaft; It is also proposed according to the invention a device for measuring the centering of a rotor in its stator in a turbine for the industrial production of electricity, the device comprising means for emitting a laser beam within the stator in order to constitute a reference axis of the measurement, the device further comprising means for measuring different lateral spacings between this laser beam forming reference axis and internal edges of the stator forming diaphragms, characterized in that the means of measurement of lateral spacings between the reference axis laser beam and the internal edges of the diaphragm stator comprise means for transmitting a second laser beam directed away from the reference axis laser beam, and means for measuring the range of said second laser beam to each said internal edge of the stator.

  Other aspects, objects and advantages of the invention will appear on reading the following detailed description of preferred embodiments thereof, given by way of nonlimiting example and with reference to the appended drawings, in which: FIG. 1 represents a possible embodiment of a device according to the invention; FIG. 2 represents another possible embodiment of a device according to the invention.

  The invention relates to the centering of an electricity generating turbine rotor within its associated stator. The rotor consists of a cylindrical shaft carrying a number of fins which constitute a set of wheels of different diameters. The stator is the very frame of the turbine. It is mounted in two parts, joined in a horizontal joint plane. The stator has a series of bearings intended to support the rotor shaft and supports diaphragms, that is to say discs arranged inside the stator and intended to carry the vanes which form partitions between the successive wheels of the rotor. rotor.

  Referring to Figures 1 and 2, there is shown the lower diaphragms 1 of a turbine stator of industrial electricity production.

  The object of the invention is to propose a method and a device for measuring the centering of a rotor in its stator within an industrial electricity production turbine.

  The device comprises means 2 for transmitting a laser beam 3 inside the stator so as to constitute a longitudinal reference axis of the measurement, as well as means for measuring different lateral spacings between this laser beam forming a laser axis. reference and internal edges of the stator forming diaphragms 1.

  The means for measuring lateral spacings between the laser beam 3 forming a reference axis and the diaphragms 1 comprise means 4 for transmitting at least a second laser beam 5 directed away from the reference beam laser beam 3, and means for measuring the range of said second laser beam 5 to each said internal edge of the stator.

  With the second laser beam directed away from the reference laser beam, a lateral spacing measurement is made, without contact, using a range measurement.

  Referring to Figure 1, there is shown a centering device 30 according to a possible embodiment of the invention.

  The device comprises a beam 6 extending longitudinally in the stator and supporting the measuring means.

  The beam 6 is advantageously formed by assembling several sections. Removable support legs 7 allow the beam 6 to be placed above the stator. These legs 7 are advantageously designed to bear on all types of turbine bodies of industrial power plants.

  The lateral spacing measuring means are means mounted in longitudinal translation on the beam and also carry a sensor 8 for positioning the laser beam 3 forming the longitudinal reference axis.

  For this purpose, a carriage 9 having the shape of a hollow parallelepiped coming to envelop the beam 6 and guided in translation along it with the aid of rollers is used.

  Motorized longitudinal displacement members are also used means 9 for lateral spacing measurement, for example in the form of a gear motor assembly and rubber roller.

  These lateral spacing measurement means 9 comprise means 4 for transmitting said second beam 5 and means 4 for measuring the range of said second laser beam as well as an arm 10 mounted to rotate around the positioning sensor 8. the laser beam 3 forming the longitudinal reference axis, which arm 10 carries these means 4 for transmitting and measuring range.

  The means 4 for transmitting and measuring range are for example adapted to be able to measure, without contact, by reflection on a diaphragm, a distance of between 100 and 300 mm, with an accuracy of the order of 0.01 mm. The length of the arm is adapted to enable said means 4 to be properly positioned at a suitable distance from the diaphragms allowing the measurement of the range of the laser 5.

  The arm is mounted so as to be able to rotate 180 around the sensor 8. The means 4 for transmitting and measuring the range can thus be oriented and thus emit said second beam 5 in a plurality of directions towards a diaphragm and thereby perform a plurality of lateral spacing measurements.

  At the level of each diaphragm, the means 4 typically measure the left, right and low spacings conventionally used to achieve a rotor / stator centering.

  Motorized rotation means, for example in the form of a motor / belt system, are also used, the arm 10 around the positioning sensor of the laser beam 3 forming the longitudinal reference axis.

  Manual remote control means of the longitudinal motorized movement and the motorized rotation movement are also provided.

  Advantageously, the lateral spacing measurement data are transmitted by infrared, via an electronic box embedded on the carriage, to a computer station having software tools adapted to process and display said measurement data.

  The operation of the centering device shown in FIG. 1 is as follows.

  Firstly, a preliminary step of measuring the positioning of a central axis of the rotor shaft is used. The position of the central axis of the rotor is then compared with the positioning of the laser forming the longitudinal reference axis. Using the comparison thus established, it is possible to correct the lateral spacing measurement results to express them with respect to the central axis of the rotor shaft.

  For this purpose, before removing the rotor, the left / right / bottom centering ribs of the rotor are measured. These ribs are located at the level of the front and rear bearings, between the structure which supports the pad of the rotor and the shaft of the rotor.

  The rotor is then removed and the beam set up. A first measurement of lateral spacing measurements is then made to determine the position of the beam in the front and rear bearings. It is thus possible to determine the position of the axis of the beam to compare it to the position of the axis of the rotor.

  It is thus possible to correct the lateral spacing measurement results to express them with respect to the central axis of the rotor shaft, which finally makes it possible to thereby establish the position of the rotor at the right of each diaphragm.

  The method according to a possible embodiment of the invention implements, at each diaphragm, lateral spacing measurements which are performed as previously indicated, without contact, using the second laser beam emitted by the means. transmitters carried by the rotary arm.

  For each diaphragm, lateral spacing measurements are typically made in three left / right / low positions, each being obtained for example by 90 offset from the axis of the arm.

  According to one possible embodiment of the invention, the lateral spacing measurements for all the diaphragms are carried out for each orientation of the arm.

  By way of example, it is possible first of all, for all the diaphragms, the measurements of left lateral spacing, without modification of the orientation of the arm. The arm is then rotated appropriately so that it can perform right lateral spacing measurements. These measurements are then made for all the diaphragms. Finally, the arm is rotated again appropriately so that it can achieve, for all the diaphragms, the low lateral spacing measurements.

  This embodiment is advantageous in that it reduces the acquisition time of the centering measurements: it effectively avoids having to rotate three times the arm at each diaphragm.

  Until now it has been considered that the beam was perfectly rectilinear, and that there is no play or mechanical defect. In fact, the beam necessarily has defects of straightness, the carriage has mechanical defects, etc. In order to correct these uncertainties, the laser beam 3 forming the reference axis, which passes through the turbine longitudinally approximately in the axis of the rotor, is used.

  The reception of the laser beam 3 is made at the sensor 8 placed on the axis of the arm 10 and for determining the positioning of said beam 3.

  Thus, since a lateral spacing measurement is made at a diaphragm, the position of the beam is also raised.

  Thus, at the right of each diaphragm of the stator, a measurement of the position of the longitudinal laser beam 3 forming reference axis, these measurements being expressed in the same predefined reference (here relative to the central axis of the beam).

  This measurement is then associated with the lateral spacing measurement between the internal border and the laser beam to obtain a measurement of the positioning of the internal rim of the rotor expressed in said predefined reference frame.

  Of course, the preliminary step mentioned above allows the lateral spacing measurement results to be expressed relative to the central axis of the rotor shaft.

  Thus, even if between two diaphragm positioning measurements, the beam is displaced, the positioning sensor 8 of the laser beam forming the reference axis makes it possible to correct the displacement and thus maintain the measurement accuracy.

  Referring to Figure 2, there is shown a centering device according to another possible embodiment of the invention.

  As means for measuring the different lateral spacings between the laser 3 forming longitudinal reference axis and the internal edges of the stator, a platform 11 is used mounted on displacement rails 12 arranged approximately in the axis of the stator. The platform 11 is thus mobile in translation approximately in the axis of the stator, extending approximately perpendicularly to said axis.

  Manual means of longitudinal displacement of the platform are advantageously provided.

  The platform 11 carries lateral spacing measuring means 14 which comprise means for transmitting three lasers 13a, 13b, 2878951 9c in the direction away from the reference laser 3, and means for measuring the range of each of said lasers 13a, 13b, 13c.

  Advantageously, the lateral spacing measurement data is processed by a computer station on the platform.

  The measuring means 14 furthermore carry a reference positioning sensor 3 of the reference laser beam 3, allowing, like the sensor 8 of FIG. 1, to express the results of the set of measurements at the level of each diaphragm in the same reference frame. predefined.

  The lateral spacing measurement means 14 comprise more precisely three fixed arms 19a, 19b, 119c, extending from the sensor 15, offset by 90 from each other, pointing respectively to the left, the right and the bottom, each of these arms carrying means for transmitting a laser 13a, 13b, 13c and means for measuring the range of said laser.

  It is thus possible to produce, at each diaphragm, three simultaneous lateral spacing measurements, respectively left, bottom and right.

  This platform 11 further comprises means 16 for transmitting a laser beam 17 towards a sensor 18 positioned at the emission means 2 of the reference laser beam 3. The positioning of the laser beam 17 is used in particular to verify that the platform is moved perpendicularly to the axis of the stator.

  The description has hitherto focused on obtaining lateral spacing measurements between the reference laser beam (defining a rectilinear virtual axis, having in particular no arrow) and the various internal edges of the stator forming diaphragms. . Of course, in order to realize the effective centering of the rotor in the stator, it is necessary to take into account the deformations of the stator (and in particular of its arrow). To this end, the invention proposes to correct the lateral spacing measurements made at each diaphragm by integrating with these so-called lateral spacing measurements of the rotor deformation measurements made in a manner conventionally known per se. Effective centering, as opposed to centering with respect to a virtual axis, of the rotor in the stator can thus be realized.

Claims (27)

  1. A method for measuring the centering of a rotor in its stator in a turbine for the industrial production of electricity, the method comprising placing a laser beam (3) within the stator in order to constituting a longitudinal reference axis of the measurement, the method further comprising a step of measuring different lateral spacings between this laser beam (3) forming reference axis and internal borders (1) of the stator forming diaphragms, characterized in that the lateral spacings between the reference beam laser beam (3) and the internal edges of the diaphragm stator are measured by emitting a second laser beam (5, 13a, 13b, 13c) away from the beam laser forming a reference axis and by measuring the range of this second laser beam to each said internal rim of the stator forming a diaphragm.   2. Method according to claim 1, characterized in that for each said inner rim of the stator forming a diaphragm, a measurement of different lateral spacings is carried out by emission of said second laser beam according to distinct directions of separation, and by measurement. for each of said distinct directions, from the range of the second laser beam to said inner rim considered of the diaphragm stator.   3. Method according to any one of the preceding claims, characterized in that it is carried out in the same preset reference a measurement of the position of the longitudinal laser beam forming reference axis to the right of each internal edge of the diaphragm stator considered, and this measurement is associated with the lateral spacing measurement between the diaphragm inner rim and the reference axis laser beam to obtain a positioning measurement of the diaphragm inner rim expressed in said predefined reference frame.   4. Method according to any one of the preceding claims, characterized in that it implements a preliminary step of measuring the positioning of a central axis of the rotor shaft and comparing the positioning of the laser forming the reference axis with this position of the axis of the rotor shaft so that one expresses the lateral spacing measurement results with respect to the central axis of the rotor shaft.   5. Method according to any one of the preceding claims, characterized in that one sets up a beam (6) extending longitudinally in the stator and supporting the measuring means (4).   6. Method according to the preceding claim, characterized in that the lateral spacing measuring means are means mounted in longitudinal translation on the beam and also carry a sensor (8) for positioning the laser beam forming the longitudinal reference axis. .   7. Method according to the preceding claim, characterized in that using members (9) motorized longitudinal displacement means for lateral spacing measurement.   8. Method according to any one of claims 6 or 7, characterized in that using lateral spacing measuring means which comprise means for transmitting said second laser beam and means for measuring the range of this said second laser beam and an arm (10) rotatably mounted around the sensor (8) for positioning the laser beam forming the longitudinal reference axis, which arm carries these emission and range measuring means.   2878951 12 9. Method according to claim 8, characterized in that means motorized rotation of the arm around the positioning sensor of the laser beam forming the longitudinal reference axis.   10. Process according to claim 7 and claim 9 in combination, characterized in that manual remote control means of the longitudinal motorized movement and the motorized rotation movement are used.   11. Method according to any one of claims 1 to 4, characterized in that it implements a platform (11) brought in translation above the stator and supporting the measuring means.   12. Method according to claim 11, characterized in that manual means for moving the platform are used.   13. Method according to one of claims 11 or 12, characterized in that the measuring means also carry a sensor (15) for positioning the laser beam forming the longitudinal reference axis.   A method according to claim 13, characterized in that lateral spacing measuring means are used which comprise a plurality of arms (19a, 19b, 19c) extending from the sensor (15), each of these arms carrying means for transmitting a laser (13a, 13b, 13c) and means for measuring the range of said laser.   15. Method according to one of the preceding claims, characterized in that the lateral spacing measurements between the reference laser beam and the internal edges of the diaphragm rotor are corrected by measuring the deformation of the rotor so as to achieve effective centering of the rotor in the stator.   2878951 13 16. Device for measuring the centering of a rotor in its stator in a turbine for the industrial production of electricity, the device comprising means (2) for emitting a laser beam (3) within the stator in order to constitute a reference axis of the measurement, the device further comprising measuring means (4, 14) of different lateral spacings between this laser beam (3) forming a reference axis and internal edges (1) of the stator forming diaphragms, characterized in that the means for measuring lateral spacings between the laser beam forming a reference axis and the internal edges of the stator forming diaphragms comprise means for transmitting a second laser beam (5, 13a, 13b , 13c) directed away from the laser beam forming a reference axis, and means for measuring the range of said second laser beam to each said internal edge of the stator.   17. Device according to claim 16, characterized in that it comprises a beam (6) extending longitudinally in the stator and supporting the measuring means.   18. Device according to claim 17, characterized in that the lateral spacing measuring means are means mounted in longitudinal translation on the beam and also carry a sensor (8) for positioning the reference laser beam.   19. Device according to claim 18, characterized in that it comprises motorized longitudinal displacement members lateral spacing measurement means.   20. Device according to one of claims 18 or 19, characterized in that it comprises an arm (10) rotatably mounted around the sensor (8) for positioning the reference laser beam, which arm carries means for transmitting said second laser beam and means for measuring the range of said second laser beam, said transmitting and reaching means forming said lateral spacing measuring means.   2878951 14 21. Device according to claim 20, characterized in that it comprises means for motorized rotation of the arm around the positioning sensor.   22. Device according to claim 19 and claim 21 in combination, characterized in that it comprises manual remote control means of the longitudinal motorized movement and the motorized rotation movement.   23. Device according to claim 16, characterized in that it comprises a platform (11) movable in translation above the stator and supporting the measuring means.   24. Device according to claim 23, characterized in that it comprises manual longitudinal displacement members of the platform.   25. Device according to one of claims 23 or 24, characterized in that the lateral spacing measurement means carry a sensor (15) 20 for positioning the reference laser beam.   26. Device according to claim 25, characterized in that the lateral spacing measuring means comprise a plurality of arms (13a, 13b, 13c) extending from the sensor, each of these arms carrying means for transmitting a laser (13a, 13b, 13c) and means for measuring the range of said laser.   27. Device according to one of claims 16 to 26, characterized in that it comprises means adapted to correct the lateral spacing measurements between the reference laser beam and the internal edges of the stator forming diaphragms so as to integrate rotor deformation measurements and thus achieve effective centering of the rotor in the stator.