FR2686745A1 - Remote controlled apparatus for eddy current and ultrasonic checking of retaining rings of turbogenerators - Google Patents

Abstract

The apparatus comprises a scanning appliance 22 which provides the simultaneous actuation of sensors for checking by eddy currents and by ultrasonics in order to carry out checking of the retaining ring 25; the scanning appliance 22 is controlled by a system 19 provided with a computer and it includes position coders for precisely positioning the sensors on the retaining ring; the scanning appliance 22 can turn around the whole circumference of the retaining ring, and it is also movable linearly parallel to the axis of the ring in order to carry out a check in a single pass; the apparatus includes special elements for data acquisition and for display of the information originating from the sensors; the retaining ring can be checked although the rotor remains in place in the stator of the generator, or also after removal of the rotor.

Description

 The present invention relates to an apparatus for controlling large cylindrical assemblies, and more particularly to a method and a control apparatus combined by eddy currents and ultrasound of retaining rings of turbogenerators.

 Generator shaft retainer rings, which are mounted at the end of a generator shaft to hold the rotor windings in place, should be checked periodically to detect faults that may have occurred inside .

Generally, this requires the owner of the machine to remove the rotor from the generator stator in order to gain access to the retaining rings. Often the rings are found acceptable to continue to operate and the rotor is replaced in the stator without the obligation to replace the retaining rings. In other cases, cracks may have occurred in the ring surface that is in contact with the rotor windings, and these cracks frequently start at locations on the inner periphery of the ring.

 To prevent a failure of the retaining rings due to the propagation of cracks, many services carry out periodic checks.

Since removal of the ring is not always practical, an ultrasonic examination is typically performed and in this case a high frequency ultrasonic signal is directed radially from the outer circumference of the ring to its inner circumference.

By monitoring the travel time of the ultrasound, and knowing the dimensional characteristics of the retaining ring, it is possible to detect small cracks that have occurred. However, these known methods generally require that the rotor be removed from the generator to carry out these checks. I1 must then operate for a long time and with precision to avoid damage to the rotor or stator during removal. It is therefore desirable to have a system which is capable of carrying out the control without the obligation to remove the rotor.

 A main object of the present invention is to create an apparatus for the control of large cylinders, without the obligation to remove the cylinder from its normal location.

 Another object of the present invention is to allow control of generator retaining rings by simultaneously bringing, from a remote location, eddy current and ultrasonic test sensors to the retaining ring.

The aims defined above and others are achieved by the present invention, according to which,
briefly, an apparatus is created to control retaining rings of a generator rotor having an outer peripheral surface t an inner peripheral surface, this control apparatus being characterized by: detector means for simultaneously detecting faults in the peripheral surface outer, in the inner peripheral surface and in the body of the cylindrical object; sounding means for bringing said collecting means onto the cylindrical object, said sounding means being able to be positioned on the circumference of the cylindrical object and axially along its length; position detection means for determining the location of said sounding means on the cylindrical object; and means for controlling the operation of the control apparatus from a remote location.

 Other characteristics and advantages of the invention will be highlighted in the following description, given by way of nonlimiting example, with reference to the appended drawings in which FIG. 1 is an overall schematic representation of the retaining ring control apparatus according to the present invention Figure 2 is a perspective view of the retaining ring probing assembly according to the present invention Figure 3 is a detailed view of the carriage assembly interior shown in Figure 2 Figure 4 is a detailed view of the eddy current / ultrasonic transducer support assembly which is shown in Figure 2; Figure 5 shows a detailed view of the ultrasonic transducer assembly of the present invention Figure 6 shows a detailed view of the eddy current transducer assembly of the present invention Figure 7 is a block diagram of the mechanism motion control for the present invention; and Figure 8 is a schematic representation of the data acquisition and control system of the transducers of the control apparatus according to the present invention.

Referring now to the detailed drawings, the retainer ring control apparatus 10 of the present invention is shown in the drawings.
Figures 1 and 2. The control apparatus 10 is composed of ultrasonic instruments 13 and eddy current instruments 16 actuated by means of a computer control station 19. These devices actuate, from a remote location, the retaining ring scanning assembly 22, which is functionally associated with a retaining ring 25 mounted on a generator rotor 28. The rotor can be either installed in, either removed from an electric generator (not shown). The retaining ring scanning apparatus comprises a first carriage, or circumferential carriage, 31 and a second carriage, or linear carriage, 34. The circumferential carriage 31 is rotated around the rotor 28 by means of a system of sprocket and chain drive 37. The linear carriage is mounted on the circumferential carriage by means of two lateral rails 40 profiled in a "U" shape and it can be moved linearly relative to this carriage. The aforementioned carriage drive systems will be described in more detail below.

 The retaining ring scanner 22 is driven over the entire periphery of the retaining ring 25 by means of the circumferential drive system 37. Chains 43 of circumferential drive are positioned around the rotor 28 in the region of the retaining ring 25. The chains 43 pass over the sounding device by means of grooves formed in curved supports 46.

This allows the linear carriage 34 to move unimpeded from one end of the retaining ring to the other, so that it is possible to examine the entire retaining ring 25 for a single installation of the sounding device. Drive sprockets 49 are engaged with chains 43 and are driven by a circumferential drive motor 52. A circumferential position correcting transducer 55 sends information to the control station 19, as will be described more fully below.

A manual belt spacing tool (not shown) is used when the scanning apparatus 22 is installed on the retaining ring 25 so as to adjust the chains to the correct axial position along the rotor.

An axial alignment is established by nylon guide wheels respectively located at the front 58 and at the rear 61. These guide wheels keep the sounding apparatus in a fixed axial position relative to a zero point on the retaining ring. This point is commonly called the retaining ring nose.

The front guide wheels 58 are arranged on pivoting arms 64 due to the small radial mounting spaces. These wheels pivot down and lock onto the nose of the retaining ring after the sounder has been placed in the correct axial position.

The rear guide wheels 61 are then positioned and locked. This sounding device is similar to that which has been described in the patent of United States of America 4,970,890 entitled "Electric Generator Inspection System", this patent having been granted to the present
Applicant and being cited here for reference.

 The linear carriage 34, shown in more detail in Figure 3, moves on eight preloaded ball bearings 67, which roll in the side rails 40, profiled in "U" and installed on the left and right on the circumferential carriage.

 Cantilever springs 70 are fixed to the linear carriage 34 and are applied by preload against the bearings so as to eliminate a radial clearance.

The preload provides a very stable and vibration-free sounding for all speeds of movement of the carriage. The linear carriage 34 is driven forwards and backwards along the central axis of the retaining ring by means of a continuous drive motor 73, sprockets 76 and a drive chain 79 reinforced by cable.

A chain clip 82 secures the carriage 34 with the chain 79. A linear corrective transducer 85 is also provided.

 Figure 4 shows the sensor support assembly -88 which is used for the installation of eddy current and ultrasonic transducers on the linear carriage 34. The ultrasonic (UT) 91 and eddy current transducers (E / C) 94 are applied by a slight spring force against the retaining ring 25, which allows them to float on irregularities of the retaining ring, such as paint bubbles and transitions in the contour of the ring . The suspension and elastic loading of the transducer support are carried out in certain ways due to the limited space available for a rotor in a non-destructive examination (NDE) installation. For some designs of retaining rings, the radial clearance is only 3.81 cm (1.5 inches), measured from the gap baffle ring (not shown) and the outer periphery of the ring nose. detention. Due to the limitation of the available space, the suspension mechanism must be made with the minimum possible radial height, which requires that the mechanism be extended circumferentially and axially. An important characteristic of the apparatus of the present invention for carrying out semi-automatic probing by eddy currents and by ultrasound relates to the particularities of self-alignment of the transducer suspensions and of the probe supports biased by springs.

Figure 5 shows a typical assembly 97 which supports UT ultrasonic transducers and which has a wedge shape. This corner is positioned manually and locked in an interior support fixator 100 by tightening a manual knob 103 -of fixator 106. The interior support fixator 100 can freely rotate freely around the rolling pivot line relative to the support of fixer 109. Also the fixer support
UT leans against the 112 definition plug xy, which is the only point of contact with the U-shaped transducer support 115. These two orthogonal suspension points allow the hydrodynamic pressure of 11 coupling agent to align the ultrasonic transducer wedge 97 in a position of tangency with the contact line on the retaining ring 25. This U-shaped transducer support 115 is part of the removable sensor receptacle 88 which is provided on the linear carriage 34. I1 Note that the UT fixator support 109 can be easily removed from the apparatus simply by lifting the U-shaped transducer support 115 to remove the sensor receptacle 88 from the linear carriage. The 112 definition xy plug is fixed on the UT 109 fixator support. This feature allows a quick change of ultrasonic assemblies, which is necessary to perform the many different probes that are to be carried out for a complete NDE control of the ring. of restraint. Also the ultrasonic transducer wedge, which is preferably formed of plexiglass, should always remain in direct contact with the surface of the retaining ring to establish optimal ultrasonic coupling therewith. Optimal coupling is established by the design of the corner with ultrasonic transducers 97. The suspension suspension design is also important to keep the corner with transducers tangent to the contact line of the retaining ring.

 Preferably, a non-hygroscopic ultrasonic coupling agent, such as Pyrogel, is pumped directly into the block 97 by means of the tapped holes 118, which are in connection with two dispersion grooves 121 with a width of 0.15 cm (0 , 06 inch). A non-hygroscopic coupling agent is preferred since stress corrosion cracking, which can occur in the retaining rings, is catalyzed by the presence of moisture. The coupling agent is forced out of said grooves 121 in all directions, in particular the area below the ultrasonic transducer 91. Tests have shown that this configuration of the corner with ultrasonic transducers makes it possible to obtain an excellent acoustic coupling, independently of the direction of movement on the surface of the retaining ring.

 The block 124 forming a support for eddy current probes is also applied elastically against the retaining ring 25 by means of four translation rods 127 which are bolted to the support of transducers 115 in a U shape and by four compression springs 130 shown in Figure 6. The contact surface of the eddy current probe block 124 is machined to match the curvature of the retaining ring. To avoid scratching the retaining ring, the block is made of a suitable material, preferably nylon impregnated with oil. The U-shaped transducer support 115 can pivot freely around the left 133 and right 136 yaw pivots relative to the removable U-shaped support 116 shown in Figure 3. In addition, the lifting of the eddy current probe.

The yaw pivot line is located near the contact surface of the retaining ring to achieve maximum stability, which allows the eddy current block 124 to pivot and thus closely follow the different contours of the retaining ring, as in the nose area. The eddy current block 124 and the inner support fixator 100 independently pivot and follow-up, which is essential for carrying out parallel eddy current and ultrasonic soundings. Tests have shown that the ultrasonic coupling agent constituted by Pyrogel has no effect on an eddy current deviation and that the eddy current block 124 has no effect on the coupling action of Pyrogel. A parallel survey saves time. Two independent eddy current probes are used to obtain a probing width of 0.508 cm (0.2 inch) and additional eddy current probes could be added to increase the probing width to any desired value.

 The removable U-shaped support 116 engages in grooves (not shown) which are machined in an assembly forming a pivoting arm 139. This arm can pivot freely more or less fifteen degrees (+ 15) relative to the linear carriage 34. The pivot arm 139 is urged by springs against the retaining ring by means of two tension springs 142 shown in Figure 3. Cables-145 are connected to each spring and pass over tension pulleys 148 while being connected to attachment points which are integral with the linear carriage 34. A pretension in the springs 142 is adjusted by adjusting the length of the cable, which in turn makes it possible to control the force exerted by the ultrasonic and eddy current transducers on the surface of the retaining ring.

 Retaining rings 25 occasionally have paint puffs and other surface irregularities which must be removed to facilitate optimal coupling of ultrasonic signals and minimal lifting of the sensors. To obtain this result, it is sometimes necessary to sandblast the outer periphery of the retaining ring by means of the pneumatic sandblaster 151 shown in FIG. 2. This sandblaster is fixed to the linear carriage 34 by replacing the support of transducers 115 in the form of a U by a special support which retains the pneumatic sandblaster 151. A simple vacuum hose is attached to the blast hood to collect debris. For visual inspection of the surface after cleaning, a fiber optic video probe (not shown), such as the 6mm version that is manufactured by Welch Allyn, has proven to be very effective.

 Figure 7 shows a block diagram of the motion control portion of the retainer ring tester 10. I1 is provided for the apparatus two axes of movement which are provided on the sounding apparatus; the circumferential drive motor 52 circumferentially displaces the retaining ring probing apparatus 22 around the retaining ring 25 while the linear carriage drive motor 73 displaces the linear carriage 34 axially above the ring. The circumferential drive motor 52 also includes an electric brake 154 fixed on it and fulfilling two functions: one consists in preventing the motor from drifting when no current is applied to the motor and the other consists in stopping the motor in an emergency situation.

 Both axes have position transducers .55, 85 which are mounted on the retaining ring probe 22 so as to transmit position information to a motion control module 157 of the computer control station 19. The circumferential position correction transducer 55 operates with reference to the belts which are used to hold the sounding apparatus 22 on the retaining ring 25 and the linear drive position correction transducer 85 is provided in relation to the belt drive which moves the linear carriage 34. Each transducer produces two trains of pulses which are electrically phase shifted by 90 degrees relative to each other and whose frequency is proportional to the speed.

The phase of the pulse train signals to the motion control module 157 in which direction the different axes are moving, and the number of pulses as well as the frequency of the pulses provide information regarding position, speed and acceleration.

 The linear carriage also includes a front limit switch 160 and a rear limit switch 163 associated therewith. These contactor limiters send a signal to the motor interface module 166 to stop the motor 73 for driving the linear carriage in order to prevent it from driving this carriage 34 too far and consequently to avoid damage to the drive system. . A voltage sensor 169 associated with the circumferential drive motor senses the voltage and a current sensor 172 associated with the circumferential drive motor measures the excitation current of the circumferential drive motor 52. For the drive motor 73 linear carriage, a voltage sensor 175 and a current sensor 178 are provided.

 There are two modes for controlling the movement of each axis. In one of the modes, one operates through the motion control module 157; this is a module equipped with a microprocessor and which uses information supplied by the transducers to control the motors and apply the correct control signals to the motor interface module 166. The other mode is a manual mode which allows control via the use of a portable remote control 181. The automatic / manual switch 184 indicates to the motor interface module 166 which mode provides effective motor control.

The useful control signals are applied to the amplifier 187 of the circumferential drive motor as well as to the amplifier 190 of the linear drive motor, these amplifiers transmitting electric current to the motors to ensure their excitation.

 Figure 8 shows a block diagram for data entry and control of the device transducers. The ultrasonic transducer (s) 91 and the eddy current transducer (s) 94 are installed in the linear carriage 34. Coupling agent also flows through an outlet from the block 97 for supporting the ultrasonic transducers, this outlet being connected to the ultrasonic transducer (s) 91 and ensuring correct transmission of the acoustic energy in the retaining ring 25 being checked. The coupling agent flow is regulated by means of a coupling agent dispensing system 193 and it can be switched on or off either by the coupling agent on / off switch 196 or by the computer 19 via the digital I / 0 module (input / output) 199.

 The ultrasonic transducer (s) 91 send their signals via a low noise coaxial cable 202 to the ultrasonic apparatus 13 which produces three types of outputs. Two analog outputs are provided, one of which is a representation of the reflected ultrasonic waveform while the other represents the peak amplitude of the reflected ultrasonic waveform in a time slot.

This signal is sampled by the analog / digital module 205. The other type of output is transmitted via a digital data bus 208 which allows the digital module I / 0 199 to communicate with the ultrasonic equipment 13.

The eddy current transducers 94 located in the linear carriage 34 are used to pick up irregularities on the outer surface of the retaining ring 25. These signals are applied to the eddy current instrument 16. The current instrument de Foucault 16 produces two analog output signals, namely an output signal 211 representing an X-position and an output signal 214 representing a Y position for each transducer 94; these signals are read by the analog-digital module 205. The combinations of the position signals X and
They are used to characterize surface irregularities.

 An analog clinometer 217 is used as an absolute positioning mechanism for the probing apparatus 22 for the retaining ring in the circumferential direction. The analog output signal from this device corresponds to the position of the retaining ring probing apparatus 22 relative to the "twelve o'clock" position. The clinometer 217 uses the gravitational field as a reference to produce this output signal. The absolute position is necessary because the circumferential position correcting transducer 55 indicates only a relative position. The displacement transducer 220 is used to correctly identify the position of the linear carriage 34 relative to the front of the retaining ring probing apparatus 22.

The operation of the apparatus and the electronic system which have been described above can be controlled by any suitable computer software. A functional description of computer software particularly usable with the preferred embodiment will be given below and suitable computer programs may be conveniently established by a specialist in this field. The system 10 can generally operate in ten modes: "Initialization" mode, "Home" mode (Zero position definition), "Time-of-Flight Table" mode (Control parameter tabulation), "Calibration" mode (Calibration), "Jog" Mode (Progress), "Auto" Mode (Automation), "Scan" Mode (Survey), "Post Mode
Processing ", Diagnostics Mode, Utilities Mode. The program includes a top level main mode from which the operator can choose one of ten system modes as mode After the system has started, the computer 19 displays a main menu allowing the operator to select one of the ten operating modes of the system.

When entering the "Initialization" mode, the computer 19 displays a data entry model on the cathode ray tube viewer 223. The operator has the opportunity to enter the following information by l '' 226 key keyboard
1. DESIGNATION OF OPERATION
2. LOCATION OF THE INSTALLATION
3. NAME OF THE OPERATOR
4. TELEPHONE NUMBER OF THE PLACE OF INSTALLATION
5. ORDER ORDER NUMBER
6. TURBOGENERATOR ORDER NUMBER
7. RETENTION RING PLAN NUMBER
8. CLASSIFICATION OF MATERIALS OF THE RING OF
DETENTION.

9. END OF THE GENERATOR ROTOR ON WHICH
THE CHECK MUST BE CARRIED OUT.

 10. REMARKS AND ADDITIONAL INFORMATION.

 Additionally, the computer 19 reads the plan file specified by the element (7) from the magnetic storage medium 229 to introduce it into its selective access memory (RAM). The plan file contains critical dimensions concerning a retaining ring of the type to be checked. Two of these dimensions, the outer diameter of the ring and its length, are used in general and are displayed on the viewer 223 for the operator. A third dimension, the ring nose length, is shown on viewer 223 and can be changed from the nominal ring nose length that is read from the plan file.

The actual ring nose length for a specific generator rotor is measured at the installation location and the input field of this value can be changed by the operator. If the retaining ring plan or these dimensions are otherwise unavailable, the device described in US Patent 5,029,476, which was issued to Metala et al. and which is owned by the present Applicant, can be used and the dimensions are entered into the RAM memory.

This patent is cited here for reference.

In part of the Initialization Mode, the operator has the possibility of indirectly introducing the speed of the shear acoustic wave (transverse wavefront) for the retaining ring 22 to be checked. This is achieved using an instrument
commercially available and operating by ultrasonic pulse echoes, and also using an ultrasonic transducer 91 which produces a normal zero degree shear wavefront at the inspection surface. The echo filtering section of the instrument 13 is adjusted in adaptation to the resonant frequency of the ultrasonic transducer, which is the same as the nominal resonant frequency of the ultrasonic transducer (s) used for the inspection of the ring. detention. The operator places the ultrasonic transducer in contact with a part of the ring to be checked, which is parallel to the axis of the generator rotor 28, and in an axial position corresponding to a known radial thickness of the retaining ring. The operator then records the time taken by the ultrasonic acoustic wave to pass through the radial thickness of the retaining ring, to be reflected by the inner peripheral surface of the retaining ring and to return to the ultrasonic instrument 13 This value, t, is introduced into the Initialization Mode data entry model.

The computer 19 calculates the measured shear wave speed using the following relation
Vs = 2X / tx 106 where
Vs = speed of the acoustic shear wave
in 11 retaining ring (centimeters / second)
X = ring thickness taken from the drawing
(in inches
t = time in microseconds for displacement
of the shear acoustic wave up to
the inner periphery of the ring of
retained and for its return to the instrument
ultrasonic 13.

 The computer 19 displays the acoustic wave speed calculated on the viewer 223 and stores this value in the RAM memory for later use. If the operator exits from Initialization Mode, the computer 19 stores the information contained in the data entry model in the RAM memory and on a magnetic recording medium 229.

 When entering the "Home" mode (Definition of zero position), the computer 19 displays an operator interface model on the viewer 223.

The "Home" mode is used to define the zero position both for the circumferential axis and for the axial axis of the retaining ring probe 22.

The operator can bring the axial axis to zero by moving the linear carriage 34 to the zero position at the nose end of the retaining ring 25. This movement is carried out using the manual remote control 181 and the movement continues until the front limit switch 160 is reached and the movement is stopped. Under the effect of position errors during an exact determination of the stop position of the linear carriage when the front limit switch 160 is reached, a displacement transducer 220 detects more precisely when the linear carriage 34 is located in the correct position relative to the front of the retaining ring probing apparatus 22. The operator signals to the computer 19 via the keypad 226 that the linear carriage has reached the zero position.

 To bring the circumferential axis to zero, the operator moves the retaining ring probing apparatus 22 to the "twelve o'clock" position.

The output signal from the analog clinometer 217 is sampled by the analog-digital module 205 and it is transmitted to the computer 19 for display on the viewer 223 in order to indicate the position "twelve o'clock" for the operator. At this time the operator signals to the computer 19 via the keyboard 226 that the sounding device 22 of the retaining ring has reached the circumferential position of zero.

 The next step is to produce a calibration factor for the circumferential position correcting transducer 55. This must be done for each retaining ring 25 mainly due to variations in ring diameters and chain lengths. From the zero position, the operator moves the sounder 22 of the retaining ring three hundred and sixty degrees (360) around the retaining ring until it reaches the same point of departure. At this time, the operator signals to the computer 19, via the keypad 226, that the retaining ring probe 22 has traversed 360. The computer 19 calculates the correct calibration factor for the circumferential position correcting transducer 55, based on the difference between the position value of zero and the position value 360 ".

 The "Time-of-Flight Table" Mode is used to create a retaining ring control parameter table based on the dimensions of the retaining ring plans and acoustic speed measurements which have been saved in "Initialization" Mode. The computer 19 determines the control parameters which are optimal for the ring to be checked. Control parameters include transducer positions, transducer corner angles, and precise times of propagation of ultrasonic waves necessary for examination of an appropriate location on the interior surfaces of the retaining ring. The control parameter table is memorized by the computer 19 in a memory with selective access for possible use in the "Scan" mode. The operator has the optional option of producing an impression of the table in a copy output printer 232.

When entering the "Scan" mode, the computer - 19 displays a submenu for initializing the survey on the viewer 223. The operator can select from this submenu a desired area of the retaining ring to be checked. Based on the operator's selection in the survey initialization submenu, computer 19 displays on viewer 223 a survey initialization data entry model that is suitable for examination to perform. Optimal survey settings for the selected exam that are produced in the Time-of-Flight Table Mode "are retrieved from memory
RAM. The computer 19 displays these parameters on the viewer 223. The operator has the optional possibility of editing these parameters. The operator can also complete the basic ultrasonic examination, which involves an inspection of the interior surfaces of the retaining ring, by an examination with eddy currents, which involves an inspection of the exterior surfaces of the retaining ring , or by other examinations using additional sensors 235. When the operations corresponding to the survey initialization data entry model are completed, the operator can signal to the computer 19, via the keypad 226, that an automated examination must be started. If the computer 19 receives the signal to start an automated examination, the following sequence of definition and movement for probing will be carried out:
1. The computer 19 transmits adjustment information
ultrasonic instruments for the examination to be carried out,
this information being transmitted to the instruments
ultrasonic 13, unless the operator has disabled
from this option in the initialization submode
survey.

2. The computer 19 sends control data entry control information to the analog-digital module 205 for the examination to be carried out, on the basis of the data extracted from the RAM memory and produced in the initialization sub-mode. survey.

3. Appropriate motion control parameters for positioning the retaining ring probing apparatus 22 for the examination to be performed are extracted from the RAM data which has been produced in the probing initialization sub-mode. by the computer 19. This data is transmitted to the motion control module 157.

4. The computer 19 signals to the motion control module 157 that a specific sequence of movements must be started for the examination to be carried out.

5. The ultrasonic instruments 13 produce an analog representation of sound echo (s) in return from the ultrasonic transducer (s) 91 to the analog-digital module 205.

6. The eddy current instruments 16 produce an analog representation of the response transmitted from the eddy current transducers 94 to the analog-digital module 205.

7. Computer 19 periodically communicates with motion control module 157 to determine when the retainer ring tester 22 has reached the next position in the appropriate motion sequence so as to signal to the analog-to-digital module 205 that it is necessary to sample one or more of the signals applied to the analog-digital module 205 in steps (5) and (6). The next position in the appropriate movement sequence to be signaled to the analog-digital module 205 is determined from the outer surface of the retaining ring which has been stored in the RAM memory during the initialization mode and from a criterion, established experimentally, for an appropriate control of the ring in this examination.

8. The computer signals to the digital analog module 205 that it is necessary to sample and digitally convert the appropriate analog signals which have been obtained in steps (5) and (6).

9. Depending on the examination being carried out, the analog-digital module 205 can transfer digitally converted data produced in step (8) to the RAM memory for use by the computer. 19.

10. Computer 19 enters digitally converted data which has been produced in step (8) in one of two ways, depending on the examination being performed
a) Data is transmitted from the analog module
digital 205 to computer 19 via
re of a common data bus shared by the computer
19 and the analog-digital module 205.

b) Data is transmitted from the analog module
digital 205 to RAM memory. Computer
19 extracts the data from the RAM memory for its
use.

11. The computer 19 displays the state of this examination on the viewer 223. The fault display option consists of a separate display of one or more real-time representations of the data extracted in steps (7) and (10). Additionally, computer 19 displays operator input options on viewer 223.

12. The computer 19 communicates periodically with the motion control module 157 to determine when the retainer ring probing apparatus 22 has reached the next position in the sequence of movements appropriate for transmission of the data entered in the step (10) to the magnetic support 229 for permanent storage.

13. The computer 19 periodically checks the digital I / O module (input / output) 199 for various system shutdown inputs.

14. Steps (1) to (13) may or may not be repeated depending on the examination being carried out. The survey sequence continues until one of the following occurs:
a) The computer 19 receives a stop signal for
step (13), at a time when the operator has the
system control.

b) Computer 19 satisfies requirements
of survey duration that have been specified in
the survey initialization submode, at a
when the operator has control of the system.

c) Computer 19 receives an established entry
by the operator via the keyboard
with keys 226 so as to suspend the sequence
survey. The operator can suspend this
poll sequence temporarily and at this time
manual movement control of the device
retaining ring sounding 22 is possible
via manual remote control
181 of motion control. Additionally,
computer 19 reads this
position of the ring sounder 22
retainer in the motion control module
157 and stores this data in the memory
RAM. The computer 19 controls the position of
the retaining ring sounder 22
from motion control module 157
and displays this information on the viewer
223. The operator can report to the computer
19, via the keypad
226, that this examination should be repeated and
at this time, the computer 19 invalidates the telecom
manual movement control 181 and
transmits appropriate command parameters
movement to the motion control module
157 with a view to gradually resuming the examination,
including the last position of the device
memorized retaining ring 22
s in RAM memory. The operator can also
stop this exam and at that moment the computer
tor 19 returns the command to the operator and
displays the survey initialization submenu.

At this time, the operator can select a
new exam or return to the main menu by
via the keypad 226.

When entering the "Calibration" mode, the computer 19 displays a calibration submenu on the viewer 223. The computer 19 reads the selection made by the operator from the submenu calibration via the 226 key keyboard. The calibration submenu offers the operator different calibration options; in two of the options, the computer 19 displays a data entry model on the viewer 223 in order to allow the operator to introduce various instrument settings relating to the ultrasonic instruments 13 and the eddy current instruments 16. A third option allows the operator to calibrate the eddy current transducers 94. To perform this operation, the "U" -shaped support 116 is removed from the retaining ring probing apparatus 22 and is fixed on a "U" bracket calibration adapter. To perform the calibration test, the adapter
"U" support calibration is moved over standard calibration reflectors
Eddy current calibration. During this movement, the calibration adapter position transducer supplies position information to the movement control module 157 and the analog-digital module 205 reads the position signals X and Y 211, 214 which are produced by eddy current instruments 16 at the same sampling speed as that used during the actual probing of the retaining ring 25.

 The eddy current calibration standard contains artificial and / or natural reflectors with known dimensions and is made of the same type of material as the retaining ring 25. The data obtained in the calibration borehole are stored by the computer 19 on the magnetic support 229. These data will be compared later with data collected on the retaining ring 25.

 When entering the "Auto" Mode, the computer 19 displays different operator options and different status items on the viewer 223. The status items include the current positions of the two axes. "Auto" Mode allows movement of the retaining ring probing apparatus 22 to a specified axial and / or circumferential position on the retaining ring 25. The operator can enter a desired position and a desired speed movement for each axis via the keypad 226 and it can signal to the computer 19 that the movement of the probing device 22 of the retaining ring must be started.

 When entering the "Jog" mode, the computer 19 displays different operator options and different status elements on the viewer 223. The status elements include the current position of the two axes. The "Jog" Mode allows the operator to manually advance the retaining ring probing apparatus 22 using the manual remote control 181. The speeds of movement of the two circumferential and axial drives can be modified using the keys to arrows on the keypad 226. The front limit switch 160 and the rear limit switch 163 will stop the linear carriage 34 to prevent it from going too far in the axial direction. When one of the two limit switches is encountered, the computer 19 displays a status signal on the viewer 223. When the emergency stop button 250 is pressed on the manual remote control 181, the computer 19 prohibits movement for both axes and activates the electric brake 154 of the circumferential drive motor. The computer 19 displays a status signal for the emergency stop condition on the viewer 223.

 When entering the "Post Processing" mode, the computer 19 displays a post-processing submenu for the operator on the viewer 223. When the operator selects the "Combine Segment Files" sub-mode coming from the post-processing submenu via the keyboard 226, the computer 19 displays a data entry model on the viewer 223 for the establishment and combination of segmented survey data files.

Segmented survey data files are data files that contain a circumferential quadrant of the retaining ring control data less than 360. The segment file combination submode provides the ability to combine quadrant data to form a complete 360-degree survey file for specific examination.

Data files for segmented survey are created during survey mode whenever a segmented survey is specified by the operator in the survey initialization submode. Segmented sounding must be specified for on-site examination of generator retaining rings in cases where full 360 ° retaining ring sounding is not possible, or in other cases where access to the ring is limited. The operator has the opportunity to enter the following information via the keypad 226
1. DIRECTION OF STARTING ROTATION IN THE QUADRANT
SURVEY.

2. PERIOD, IN DEGREES PER SAMPLE, OR DATA
SAMPLE ANALOGUE WAS SAMPLED.

 3. DESIGNATION OF THE QUADRANT FILES TO BE COMBINED.

4. QUADRANT DIMENSION, IN DEGREES, FOR EACH
FILE INTRODUCED IN (3).

The operator can signal to the computer 19 via the keyboard 226 that it is necessary to display on the viewer 223 a directory of appropriate file designations which have been stored on the magnetic medium 229. The computer 19 calculates the circumferential boring length of each file specified in step (3) using the following relation
s = qxP where
s = circumferential sounding length of the file
in samples.

q = quadrant dimension in degrees for the file
introduced in (3).

P = sample period, in degrees per sample
introduced in (2).

 The computer 19 displays the circumferential sounding length for each file designation on the viewer 223, following an entry by the operator of the elements (3) and (4). The operator can signal to the computer 19, via the keypad 226, that a combination of the segmented survey data files must be started. On reception of this signal, the computer 19 validates the data files introduced in step (3) and, if the result is satisfactory, it assembles sounding lines of length s for each file designation introduced in l 'step (3) in the correct sequence to produce a survey file whose survey length is equal to the sum of the values' of s that have been calculated for each segmented survey data file. The computer 19 stores the combination of survey files on the magnetic support 229.

 When the operator selects the combined exam submode from the post-processing submenu, via the keyboard 226, the computer 19 displays a data entry model on the viewer 223 with a view to establishing and combining 360-degree survey files, stored on the magnetic support 229.

360-degree survey files from different exams can be combined to produce an output file whose data represents the entire interior or exterior peripheral surfaces of the retaining ring. The operator has the opportunity to enter the following information via the keypad 226
1. TYPE OF OUTPUT FILE
2. REFERENCE OFFSET OF ZERO CIRCUMFERENTIAL
3. AXIAL ZERO REFERENCE SHIFT
4. PERIOD, IN DEGREES, OR A SURVEY DATA A
SUMMER SAMPLE
5. FILES TO COMBINE
6. ANGLE OF REFRACTED SOUND BEAM USED
DURING THE CHECK RING INSPECTION, IF
THIS IS APPLICABLE FOR THE FILE TYPE
SPECIFIED IN STEP (1).

 The computer 19 calculates the survey length of the survey files over 360 degrees using the relationship indicated during the description of the segmented file combination submode and displays this value on the viewer 223 for the operator below. from step (4). Additionally, the computer 19 calculates the number of polls involved in each file introduced in step (5) by determining the number of data samples in each file and by dividing this number by the calculated poll length. The computer 19 then displays on the viewer 223 the number of polls per file following the entry of each file designation in step (5). The operator can signal to the computer 19, via the keypad 226, that a directory of file designations appropriate for step (3) must be displayed, these designations being contained in the storage medium. magnetic 229. The operator can signal to the computer 19 via the keypad 226 that a combination of files specified in step (5) must be started in order to produce an output file of the type specified in step (1). Upon reception of this signal, the computer 19 will validate the designations of files entered and will combine survey lines in the correct sequence, from each of the validated files, in the form of a single file.

The computer 19 will additionally carry out an adjustment of the survey data, as appropriate for the following operations.
a) Omission of survey files necessary for
produce a complete output file of the type
specified in step (1).

b) Alignment of survey file data
with zero reference positions on the ring
controlled restraint, based on offsets
introduced in steps (2) and (3), of the angle
of refracted sound beam introduced in the step
(6) (if applicable), and constants
mechanical shifts of transducers 91
and / or 94 (if applicable) in the device
retaining ring boring 22.

 When the operator selects the "Plot" submode from the post-processing submenu via the keyboard 226, the computer 19 displays on the viewer 223 a model of data entry for the establishment and tracing of combined exam files produced in the combined exam submode. The computer 19 extracts from the RAM memory data of applicable texts which have been introduced in the initialization mode and it displays this information on the viewer 223.

The operator can enter a file designation representing a combined exam file for tracing via the keypad 226.

The operator can edit text data and other plot parameters via the keypad 226. When receiving the appropriate signal from the keypad 226, the operator 19 reads the log file. data to be plotted on the magnetic storage medium 229 and it displays a color representation of the data on the viewer 223. The computer 19 compresses the data which have been read from the file, as is necessary for plotting the data in a acceptable size, preferably 8-1 / 2 x 11 inches (21.5 x 28 cm). Data compression is performed by plotting the maximum amplitude of data sampling for all x data samples, where x is a scaling factor based on the size of the data file. Additionally, the computer 19 displays appropriate scales for the axial, circumferential and amplitude information which are contained in the data file. The computer 19 also displays text information appropriate for the particular set of data. Upon receipt of the appropriate signal from the keypad 226, the computer 19 transmits a representation of the image displayed on the viewer 223 to the copy output printer 232.

 When entering the "Diagnostics" mode, the computer 19 displays a diagnostic submenu on the viewer 223. From this menu, the operator can select different options which, when selected , will force the computer 19 to run system diagnostic tests and display the test results on the viewer 223.

 When entering the "Utilities" Mode, the computer 19 displays an operating submenu on the viewer 223. From this menu, the operator can select different options relating to manipulations files, formatting of magnetic media, setting times and dates for computer 19, as well as other operating functions which are common for computer systems control software.

Claims (10)

 1. Control apparatus for retaining rings of generator rotors, comprising an outer peripheral surface and an inner peripheral surface, apparatus characterized in that it comprises - capture means (91, 94) for simultaneously detecting faults in the outer peripheral surface, in the inner surface and in the body of the cylindrical object (25) - scanning means (22) for bringing said collecting means (91, 94) onto the cylindrical object, said scanning means (22) which can be positioned around the circumference of the cylindrical object (25) and axially along its length - position detection means for determining the location of said scanning means (22) on the cylindrical object (25); and - means (19) for controlling the operation of the control equipment from a remote location. 2. Control apparatus according to claim 1, characterized in that said collection means comprise an eddy current probe (94) for detecting faults in the external peripheral surface and an ultrasonic transducer (91) for detecting faults in the inner peripheral surface and in the body of the cylindrical object (25). 3. Control apparatus according to one of claims 1 or 2, characterized in that said scanning means (22) comprise a first carriage (31) having a longitudinal axis and means for rotating the first carriage (31) around the circumference of the cylindrical object (25), as well as a second carriage (34) fixed on the first carriage (31), this second carriage (34) comprising means for ensuring its translation along the longitudinal axis of the first carriage (31). 4. Control apparatus according to claim 3, characterized in that said means for driving the first carriage in rotation (31) comprise a drive chain (43) which can be fixed around the circumference of the cylindrical object, a circumferential drive system coupled to the first carriage (31), this circumferential drive system further comprising a first drive motor (52) fixed on the first carriage (31), this first drive motor (52) comprising a pinion (49) which is functionally fixed on it, this pinion (49) being engaged with the drive chain (43) so that the first carriage is rotated around the circumference of the cylindrical object ( 25) when the first drive motor (52) is active. 5. Control apparatus according to claim 3, characterized in that the first carriage (31) comprises two profiles (40) having overall a U-shaped section and oriented along its longitudinal axis, and said means for ensuring the translation of the second carriage (34) comprise a support (-1-1-6) adapted to engage by sliding in said U-shaped profiles, a linear drive chain (79) generally arranged along the longitudinal axis of the first carriage (31), a chain link (82) comprising a part fixed on the linear drive chain (79) and another part fixed on the second carriage (34), and means for driving the linear drive chain (79) along the longitudinal axis of the first carriage (31) so that the second carriage (34) is driven in translation along the longitudinal axis of the first carriage (31). 6. Control equipment according to claim 5, characterized in that the second carriage (34) -comprises means allowing the mounting on the carriage of said capture means (91, 94), said mounting means comprising - a set (139 ) forming a pivoting arm, which is connected to the second carriage (34) so as to be able to pivot around an axis perpendicular to the longitudinal axis of the first carriage (31) and adapted to ensure that said capture means (91 , 94) come into contact with the surface of the cylindrical object (25); - a first support (116) removably fixed on the assembly forming a pivoting arm (139) - an assembly (88) forming a support of capture means, adapted to be fixed on the first support (116), said assembly ( 88) which can pivot relative to the first support (116) so that said capture means (91, 94) mounted on it are held against the cylindrical object (25). 7. Control apparatus according to claim 6, characterized in that said collecting means comprise an eddy current probe (94) for detecting faults in the external peripheral surface and an ultrasonic transducer (91) for detecting faults in the inner peripheral surface and in the body of the cylindrical object (25). 8. Control apparatus according to claim 1r characterized in that the scanning means (22) comprise - a drive chain (43) which can be fixed around the circumference of the cylindrical object (25); - a circumferential drive system coupled to the first carriage (31), this circumferential drive system further comprising a first drive motor (52) fixed on the first carriage (31), this first drive motor being provided a pinion (49) which is engaged with the drive chain (43) so that the first carriage (31) is rotated around the circumference of the cylindrical object (25) than the first motor drive (52) is actuated - a pair of profiles (40) generally having a U-shaped section, located on each side of the first carriage (31) and oriented along its longitudinal axis; - the second carriage (34) comprising a support (116) adapted to slide into said U-shaped sections (40); - a linear drive chain (79) arranged overall along the longitudinal axis of the first carriage (31); - a chain attachment (82) comprising a part fixed to the linear drive chain (79) and another part fixed to the second carriage (34); - a second drive motor (73) for driving the linear drive chain (79) along the longitudinal axis of the first carriage (31) so that the second carriage (34) is moved in translation along the longitudinal axis of the first carriage (31); and in that said position detecting means for determining the location of said sounding apparatus (22) on the cylindrical object (25) comprises a circumferential position correcting transducer (55), operatively connected to the circumferential drive system ( 52), and a linear position correcting transducer (85) operatively associated with the linear drive motor (73), so that output signals from the circumferential and linear position transducers (55,85) are transmitted to said control means (19) for determining the positions of said first and second carriages (31, 34) of said scanning apparatus (22). 9. Control apparatus according to claim 8, characterized in that said assembly forming support for capture means comprises a support in U (115) removably attached to the first support (116), this U-shaped support (115) being able to pivot relative to the first support (116) about an axis perpendicular to the longitudinal axis of the first carriage (31) , a first mounting block (124) adapted to receive an eddy current probe (94), this first mounting block (124) being fixed to the U-shaped support (115) by compression springs (130), and a second mounting block (97) fixed on the U-shaped support (115) and able to pivot orthogonally relative to the latter, this second mounting block (97) being adapted to receive an ultrasonic transducer (91). 10. Control apparatus according to claim 9, further characterized in that it comprises means (193) for supplying coupling agent to the cylindrical object (25) for use with the ultrasonic transducer (91), the second mounting block (97) comprising first means for receiving the coupling agent from a power source and second means for sending the coupling agent to the cylindrical object (25) .