EP0038270B1 - Means for supporting and guiding a tool at the interior of a hole - Google Patents

Abstract

A supporting and centering arrangement in the form of a star the arms of which are radial with respect to a tapping to be machined or checked. These arms have elements for centering and fastening them to the tapped wall, as well as a centering element at the projecting end of the tapping. The support and the centering element carry bearings. A tool holder bar connected to two rotating stub shafts is mounted off-set from the axis of the bearings in the radial direction of the tapping. The bar supports a tool guide, and is rotatable about the axis of the tapping. The device is especially useful for machining and checking tappings formed in a pressurized water nuclear reactor tank.

Description

The invention relates to a device for supporting and moving a tool inside a nozzle passing through a wall so as to be flush with one side of the wall and protruding from the other side.

In heavy boilermaking components, in particular nuclear pressurized water reactor vessels, outlets or arrivals of pipes in the vessel, or tappings, are formed in the wall of the vessel so as to allow connection, outside of this tank, between the tapping and an arrival or departure pipe.

Such tappings are formed in the wall so that the tapping is flush with the internal surface of the tank and is fairly widely projecting outside the tank for its connection with a pipe of the primary circuit of the reactor bringing the water under pressure. in the tank or, on the contrary, allowing the exit of this water which acts as a coolant in the reactor core, outside the tank for its sending to the steam generators.

The internal surface of the tank, as well as the internal surface of the nozzles, must be coated with a layer of stainless steel and it is necessary to carry out a quality control of this coating, in particular inside the nozzles made in the wall of the tank.

Such checks assume a very good condition of the surface of the covering and it is necessary to grind the entire internal surface of the nozzle before starting the checking operation.

On the other hand, when defects are detected, it is necessary to carry out machining deeper than a surface grinding to know what is the depth of these defects.

To carry out the machining operations or the control operations, it is necessary to move a tool or a control means inside the nozzle to make this tool or this control means occupy different positions making it possible to reach the different areas of the lateral surface of the stitching.

In the case of pressurized water reactor tanks, the machining or controls inside the taps of the primary circuit are generally carried out when the tank is in the vertical position, that is to say with taps whose axes are practically horizontal.

These operations are currently carried out manually and are therefore extremely painful, since it is necessary to work with very different positions of the tool while the internal diameter of the nozzle is relatively small.

Likewise, the proper execution of the work inside the nozzle is limited by the fact that accessibility is not very good, the internal diameter of this nozzle being relatively small. In some cases, the space available is not even sufficient to allow the use of certain tools.

The taps of the pressurized water inlet pipes to the reactor vessel have, on the other hand, a tapered bore which further complicates manual machining operations in order to achieve a good surface condition.

More generally, when it is desired to carry out machining or control operations in tappings formed in the wall of a large boilermaking component, one encounters difficulties due to the smallness of the space in which one must carry out the machining, at the various positions which it is necessary to make take with the tool or by means of control to follow the internal surface of the tapping, and to the fact that the internal bore of these tapping a cylindrical shape.

In U.S. Patent _No. 4161127-A describes a device for machining the inner surface of a nuclear reactor vessel in the vicinity of a nozzle and around the latter, for the repair of cracks. This device comprises a centering piece disposed inside the tapping, a tool support carried by the projecting end of the tapping and a tool bar mounted rotatably in the centering piece and in the support, directed along the axis of the stitching and associated with rotation drive means carried by the support. At its end opposite to the support, inside the tank, the bar carries a cutting tool which can move axially with the bar, for a small distance and radially with respect to the bar, during the rotation of the latter .

Such a device can only be used for machining inside the tap since the centering piece occupies a large part of the internal volume and surface of this tap and the tool bar can only move axially over a very short distance corresponding to the penetration depth of the tool. The tapping ensures the fixing and centering along its axis of the tool bar, the support and actuation means of which are arranged outside the tank, the tool working inside the tank only.

Finally, this device does not make it possible to adjust the tool as a function of the shape and size of the stitching.

The object of the invention is therefore to propose a device for supporting and moving a tool inside a nozzle having a symmetry of revolution and passing through a wall so as to be flush with one side of the wall and to be protruding on the other side, comprising a centering piece inside the tap, a support means fixed centrally at one end of the tap and a tool bar rotatably mounted around the axis of the tap in bearings carried by the centering piece and the support means and associated with rotation means, the device allowing automation of the work carried out with the tool, precise positioning of the tool at any point on the internal surface of the tapping and an adaptation to different types of profiles and to different dimensions of the internal bore of the tapping.

• - le moyen de support est en forme d'étoile, dont les branches sont disposées rayonnantes par rapport au piquage et portent des pièces de centrage destinées à s'engager dans l'orifice du piquage et des moyens de fixation sur la paroi du côté où affleure le piquage,
• - la pièce de centrage à l'intérieur du piquage est disposée à l'extrémité saillante du piquage,
• - la barre porte-outil, reliée à deux portions d'arbres alignées suivant l'axe du piquage, tourillonnant chacune dans un des paliers, est montée de façon décalée par rapport à l'axe du piquage dans une direction radiale,
• - l'outil est mobile sur la barre porte-outil dans la direction axiale et dans des directions radiales du piquage, grâce à des moyens de guidage et de déplacement portés par la barre porte-outil.

For this reason:

• - The support means is in the shape of a star, the branches of which are arranged radiating with respect to the nozzle and carry centering pieces intended to engage in the orifice of the nozzle and fixing means on the wall on the side where is flush with the stitching,
• - the centering piece inside the nozzle is arranged at the projecting end of the nozzle,
• - the tool bar, connected to two portions of shafts aligned along the axis of the nozzle, each swiveling in one of the bearings, is mounted offset from the axis of the nozzle in a radial direction,
• - The tool is movable on the tool bar in the axial direction and in radial directions of the stitching, by means of guidance and displacement carried by the tool bar.

• La fig. 1 représente, dans une vue en élévation, avec coupe partielle, l'ensemble du dispositif en position à l'intérieur de l'alésage cylindrique d'un piquage formé dans la paroi d'une cuve de réacteur nucléaire à eau sous pression.
• La fig. 2 représente une vue en coupe suivant A-A de la fig. 1 à une plus grande échelle.
• La fig. 3 représente une vue à plus grande échelle de la partie de droite de la fig. 1.
• La fig. 4 représente une coupe suivant C-C de la fig. 3.
• La fig. 5 représente une coupe suivant B-B de la fig. 1.
• La fig. 6 représente, dans une vue en élévation avec coupe partielle, l'ensemble du dispositif en position dans un alésage de forme conique d'un piquage formé dans la paroi d'une cuve de réacteur à eau sous pression.

In order to clearly understand the invention, we will now describe, by way of nonlimiting example, with reference to the attached figures, an embodiment of the support and displacement device according to the invention in the case where this device is used for machining and control operations in connections from a tank of a pressurized water nuclear reactor.

• Fig. 1 shows, in an elevational view, with partial section, the entire device in position inside the cylindrical bore of a nozzle formed in the wall of a nuclear pressurized water reactor vessel.
• Fig. 2 shows a sectional view along AA of FIG. 1 on a larger scale.
• Fig. 3 shows an enlarged view of the right part of FIG. 1.
• Fig. 4 shows a section along CC of FIG. 3.
• Fig. 5 shows a section along BB of FIG. 1.
• Fig. 6 shows, in an elevational view with partial section, the entire device in position in a conical bore of a nozzle formed in the wall of a pressurized water reactor vessel.

In fig. 1, we can see a part of the wall 1 of a pressurized water reactor vessel in which has been formed a nozzle 2 which is practically flush with the interior surface 1a of the wall 1 of the vessel and which is projecting with respect to the outer wall 1b of this tank.

The internal bore 3 of the tap 2 is of cylindrical shape.

The device for supporting and moving a grinding tool in the tapping bore shown in FIG. 1 comprises a handling chassis 6, a star support 7, a tool bar 8 and a centering bell 9.

The handling chassis is constituted by a bracket formed by two beams 10 and 11 of rectangular section, the beam 10 being arranged vertically and the beam 11 horizontally when the device is in position inside the tank 1 vertical.

The horizontal beam 11 carries a handling lug 12 allowing the transport of the device as a whole with an overhead crane. This beam 11 is supported on the upper part of the tank 1 by means of two supports 13 constituted by screws allowing the verticality of the handling chassis to be adjusted in position on the tank. At the end of the beam 11 is also arranged a means of fixing the handling chassis to the tank consisting of an arm 14 held in position at the end of the beam 11 by pins 15 introduced into openings of the fixing arm 14.

A screw 16 allows the handling chassis to be locked in position on the upper part of the tank. The handling chassis 6 also carries an electrical cabinet 17 allowing the supply of the motor components of the device.

The handling chassis 6 is connected to the star support device 7 by bolting at a junction plate 18 ensuring the connection between the lower end of the handling chassis and one of the branches of the star support 7.

The support 7 consists of three branches 7a, 7b, 7c arranged with, for the plane of symmetry, planes containing the axis xx 'of the branching called radial planes.

The branches 7a, 7b, 7c are arranged with a certain inclination relative to the vertical in a radiating manner with respect to the nozzle when the device is in position as shown in FIG. 1.

The branch 7a is formed at its end by a beam portion 19 allowing the connection of the branch 7a with the frame 6. This end portion 19 of the branch 7a carries, on the other hand, a suction cup 20 whose position is adjustable with respect to the branch 7a by means of a screw 21. The beam 19 also carries a centering bracket 23 intended to come to engage in the orifice of the bore 3 flush with the internal surface 1a of the tank, this bracket itself carrying a lug 24 allowing the support on the internal surface 1a of the tank.

In the same way, the branches 7b and 7c respectively comprise adjustable suction cups 20b and 20c and support brackets 23b and 23c arranged at the end of the oblique branches 7b and 7c to allow the centering and the attachment of the device on the internal surface of the tank at the nozzle. The pins 24b and 24c associated with the arms 7b and 7c respectively are adjustable by means of jacks 22.

At the center of the star is fixed a bearing 25 in which a shaft 26 is pivoted in an axial direction relative to the nozzle. The shaft 26 is connected to the tool bar 8 by means of a device 30 allowing an inclination adjustment. The device 30 will be described in more detail with reference to FIGS. 3 and 4.

At the end of the shaft 26 is fixed a flywheel 31 making it possible to manually rotate the shaft 26 from a work floor inside the tank.

The end of the shaft 26 is also secured to a toothed wheel 34, meshing with a pinion 35, driven by a motor 36 carried by the branch 7a of the star.

The centering bell 9 introduced into the protruding end of the nozzle comprises a cylindrical jacket 38 carrying, on its external surface, sliding pads such as 39 facilitating the introduction of the centering bell in the nozzle, and an inflatable seal 40 disposed inside a groove machined in a projecting part of the external surface of the bell 38.

At the central part of the cylindrical envelope 38 of the bell is fixed a bearing 41 constituted by a tube made integral with the bottom of the bell 38 by ribs 42.

In the bearing 41 is engaged a shaft 44 connected in an articulated manner to the end of the tool bar 8 as will be explained with reference to FIG. 2. The shafts 26 and 41 are aligned and arranged axially with respect to the nozzle, that is to say, in the case of FIG. 1, in a horizontal direction.

The tool bar 8 is provided over its entire length with a dovetail profile slide 46 and a screw 47 mounted in bearings such as 48 allowing the movement of the tool 50 constituted by a grinding wheel and its drive motor in the axial direction of the stitching.

The tool will be described in more detail with reference to FIG. 5.

In fig. 2, we see the axis 44 journalling inside the bearing 41 disposed in the center of the cylindrical bell 38 in an axial direction.

The shaft 44 is secured to a bracket 50, the horizontal part of which enables the tool-holder bar 8 to be fixed in a precise position with regard to its orientation relative to the shaft 44. For this, the bar 8 is secured a sleeve 51 in the central bore of which passes an axis 52 fixed, relative to the bracket, by means of screws 53 and, relative to the sleeve 51, by a nut 54 engaged on the threaded upper end of the shaft 52. Openings in the sleeve 51 and keys 55 make it possible to maintain the shaft 8 in a constant angular position relative to the shaft 44 of axial direction, if we consider a rotation around the axis 52.

In all cases, it can be seen that the longitudinal axis yy 'of the tool bar 8 is offset in the radial direction relative to the axis xx' of the tapping.

The shaft 44 is pierced at its center with a channel 57 allowing the supply of control fluid to the inflatable seal 40.

In fig. 3 and 4, we see the shaft 26 of axial direction mounted journalling in the bearing 25 and connected via a sleeve 65 and stiffeners 64 to a plate 62, the stiffeners 64 being welded, on the one hand, to the sleeve 65 and, on the other hand, to the plate 62.

The plate 62 has two holes 63a inside which pass screws 63b making it possible to secure the shaft 26 and the tool bar 8.

The tool bar 8 is secured to a fixing plate 61, however a support plate 60 is interposed between the plate 62 secured to the shaft 26 and the plate 61 secured to the support bar d tool 8.

The support plate 60 is pierced with holes 68 centered on the vertical axis of this plate 60.

The concordance between the holes 63a and 68 makes it possible to secure the plates 60 and 62 by means of the screws 63b.

The plate 61 secured to the tool bar 8 comprises two sets of two threaded holes 67 whose spacing corresponds to the spacing of the holes 63a of the plate 62.

In fig. 3, a first set of holes 67 of the plate 61 has been placed in accordance with the holes 63a and 68, so that the screws 63b allow the shaft 26 and the tool bar to be secured so that the axis of this tool bar 8 is parallel to the axis of the shaft 26, that is to say to the axis of the nozzle.

This corresponds to the position of the tool shown in fig. 1 where the rotation of the axis 26 by means of the toothed wheel 10 allows the grinding wheel of the tool 50 to describe the cylindrical internal surface of the bore of the tap 2.

The second set of holes 67, when brought into concordance with the holes 63a and 68, allows the plate 61 to be placed in the position 61 'shown in broken lines in FIG. 3. For this, it suffices to unscrew the screws 63b and to move the plate 61 integral with the tool-holder bar 8 downwards, then to rotate it slightly to bring the holes 67 in line with the holes 63a and 68. The shaft 26 and the tool bar 8 can then be secured again using the screws 63b which are fixed in the second set of holes 67 of the plate 61.

The axis of the tool bar 8 is then inclined relative to the axis of the shaft 26, that is to say relative to the axis of the tap 2.

The device is then in the position shown in FIG. 6.

The arrangement of the two sets of holes 67 on the plate 61 is chosen so as to bring the axis of the tool-holder bar in the direction of a generator of the cone constituting the bore of the tap 2 'shown in FIG. 6.

In fact, in the pressurized water nuclear reactor vessels, the tappings are of two types, some with cylindrical internal bore, and the others with conical internal bore. With a plate comprising two sets of holes 67 as shown; the device can therefore be obtained very quickly and very easily from the machining position in a cylindrical bore to the machining position in a conical bore.

Indeed, during the rotation of the shaft 26, the grinding wheel of the tool 50 can then describe a conical surface corresponding to the interior surface of the bore.

Referring to figs. 1 and 5, the assembly of the tool 50 is seen, consisting of a grinding wheel 70 mounted on an axis 71 driven by a motor 72 by means of a belt 73.

All of the tools are fixed to a frame 74 mounted sliding on the dovetail slide 46 secured to the tool bar 8. On the other hand, the frame 74 carries a nut 75 in engagement with the screw endless 47 driven in rotation by a motor carried by the tool bar 8.

In this way, all of the tools can move axially in the bore by moving along the slide 46 of the tool bar 8.

The axis 71 of the grinding wheel 70 is, on the other hand, rotatably mounted in a barrel 77 which can be moved along its axis by a jack 78, relative to the frame 74 of the tool. The penetration movements of the grinding wheel in the coating metal of the tapping bore are thus carried out.

A set of pulleys 79 makes it possible to send the electrical wires or fluid supply tubes to the various motors or jacks carried by the tool bar and the tools.

For the commissioning of the support and displacement device which has just been described, we begin by making various settings on the device making it possible to adapt it to the stitching on which the machining is carried out.

This is how the squares 23 are adjusted when the nozzle is opened, a bell 38 with a diameter corresponding to the internal diameter of the nozzle is chosen and the inclination of the tool bar 8 is chosen. relative to the axis of rotation of this bar so that it adapts to the geometry of the nozzle. On the other hand, a tool suitable for the machining to be carried out is placed on the tool bar.

These various adjustments made, the tool is placed in the raised position and the suction cups in the rear position.

The device is then introduced into the nozzle by carrying out its handling using the lifting lug 12 until the bell is in its final position at the end of the protruding part of the nozzle. The pins 24 are placed in position against the internal wall of the tank and the seal 40 of the bell 28 is inflated by sending the seal control fluid through the central channel 57 of the shaft 44.

The position is then adjusted and the tool is fixed using the shaft 14 and the screws 12 and 16.

The suction cups 20 are then adjusted by action on the screws 21 so that these suction cups come into contact with the internal wall of the tank. These suction cups 20 obviously have a contact surface constituting a cylinder portion to allow them to perfectly match the internal surface of the tank.

The suction cups are then placed under vacuum, which keeps the device in place independently of any other support. One then chooses the working parameters of the tool which is started from a control box arranged on the part of the device which is inside the tank.

If you wish to rectify the entire internal surface of the tapping, you can make a step-by-step advance of the grinding wheel in the axial direction and rotate the tool bar a little more than 360 ° to carry out a complete sweep of the surface with a slight overlap. Each of the step-by-step advances is obviously chosen so that its amplitude is less than the working width of the grinding wheel.

In this case, after the installation of the tool and the suction of the suction cups 20, the centering brackets 23 are dismantled, which makes it possible to carry out a scanning of the internal surface of the nozzle by the grinding wheel up to the end of this nozzle flush with the internal surface of the tank.

We see that the main advantages of the device according to the invention are to allow automation of the machining operations in a tapping and the use of more bulky tools, to have a large power at the end of the shaft and to allow adaptation to various geometries of the stitching.

On the other hand, in the case of a rectification of the internal surface of the grinding with the grinding wheel, the regularity of the grinding compared to a manual grinding makes it possible to obtain a surface of very good quality.

It is also possible to completely isolate the nozzle during the operations carried out there thanks to the inflatable joints of the centering bell.

Finally, the use of the device according to the invention is particularly simple and particularly safe.

Furthermore, instead of using a grinding wheel for the operations of grinding the stitching, it is possible to use an abrasive belt passing over a pulley and a support wheel driven in rotation by a motor.

Instead of a grinding tool, a tool can be placed on the tool bar allowing any operation to be carried out inside the nozzle at any point in the bore of this nozzle.

One can, on the other hand, use different fixing means of suction cups hung against the internal wall where the nozzle opens. One can also imagine other embodiments of the device with variable inclination of the tool bar.

The use of the device according to the invention is of course not limited to machining operations and it is possible to carry out non-destructive checks inside a nozzle by replacing the tool mounted on the door bar. -tool by a control means which can be moved into positions allowing the control of the entire internal surface of the bore.

Finally, it is possible to conceive of applications of the device according to the invention in fields other than the construction of the nuclear reactor vessels, for example the construction of other large forged or boiled containers having nozzles of any shape.

Claims (6)

1. Deviceforsupporting and moving a tool (50) inside a penetration (2) having a symmetry of revolution and passing through a wall so as to be flush with one side of the wall and to project from the other side of the wall, comprising a piece (9) for centering inside the penetration (2), a supporting means (7) fixed to one end of the penetration so as to be centered, and a tool-carrying bar (8) mounted so as to rotate about the axis of the penetration in bearings (25, 41) carried by the centering piece (9) and by the supporting means (7) and associated with means for causing rotation (34, 35, 36), the supporting means (7) and the centering piece (9) having the axis of the penetration as their common axis, characterised in that:

- the supporting means (7) is in the shape of a star whose arms (7a, 7b, 7c) are arranged so as to radiate relative to the penetration (2) and carry centering pieces (23), intended to fit into the orifice (3) in the penetration (2), and means (20) for fixing to the wall (1 a) on the side where the penetration (2) is flush,

- the piece (9) for centering inside the penetration (2) is arranged at the projecting end of the penetration (2),

- the tool-carrying bar (8), joined to two shaft portions (26, 44) aligned along the axis of the penetration (2) and each swivelling in one of the bearings (25,41), is mounted offset relative to the axis of the penetration (2) in a radial direction, and

- the tool (50) can move along the tool-carrying bar (8) in the axial direction and in the radial directions of the penetration (2) by virtue of guiding and displacing means (46, 47) carried by the tool-carrying bar (8).

2. Supporting device according to claim 1, characterised in that the tool-carrying bar (8) is joined to the shaft portions (26, 44) via devices (51, 52 and 30) making it possible to orientate the tool-carrying bar (8) either parallel to the axis of the penetration (2) or in at least one direction inclined relative to this axis, in order to cause the tool (50) to describe a conical surface during the rotational movements of the tool-carrying bar (8) and the axial movements of the tool (50).

3. Supporting device according to claim 2, characterised in that the tool-carrying bar (8) is joined to the shaft portion (44) mounted in the bearing (41), firmly fixed to the centering piece (9), viaan axle (52) perpendicular to the axis of this bearing (41 ), making it possible to orientate the tool-carrying bar (8) relative to the axis of the bearing (41), and is joined to the shaft portion (26) mounted in the bearing (25), joined to the star-shaped support (7), via fixing plates (61, 62) carried in one case by the tool-carrying bar (8) and ih the other by the shaft portion (26), at least one of which plates (61) possesses at least two sets of holes (67) for fixing by means of screws (63b) in order to obtain two different inclinations of the tool-carrying bar (8) relative to the axis of the penetration (2).

4. Supporting device according to any one of claims 1 to 3, characterised in that the star-shaped support (7) is joined to a right-angled holding and supporting frame (6) capable of coming to rest on the upper part of the wall (1) through which the penetration (2) passes.

5. Device according to any one of claims 1 to 4, characterised in that the means for fixing the star-shaped support (7) to the wall (1) on the side (1 a) where the penetration (2) is flush consist of suction pads (20).

6. Supporting device according to any one of claims 1 to 5, characterised in that the centering piece (9) arranged at the projecting end of the penetration (2) consists of a cylindrical cap (38) carrying an inflatable gasket (40) on its outer surface.

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