EP0094703A2 - Sustaining device and control mechanism for the synchronisation of the displacement of a travelling bridge - Google Patents

Abstract

1. A rotating travelling bridge crane consisting of bearing girders connected together by tie plates (2) to form a rigid rectangular frame (3) equipped in the vicinity of its corners with mobile, ball-jointed supporting devices each resting on a slewing support beam (4 to 7) guided along a circular runway by horizontal rollers (31) resting on concentric rails (24) in order to absorb the forces oriented in a diametral direction (X), characterized in that at least one horizontal roller (31') is carried by one of the tie plates and in that the ball-jointed supporting devices (12) are equipped with a unidirectional slide plate (13) with a very low friction coefficient allowing displacement in a diametral direction (X) according to the forces transmitted by the above-mentioned horizontal rollers (31).

Description

The subject of the present invention is a rotary overhead crane consisting of load-bearing beams connected together by connecting crosspieces to form a rigid rectangular frame bearing, in the vicinity of each corner, on a girder base moving on a circular raceway .

The revolving crane is used mainly in a nuclear power plant. It is generally installed at the top of the containment which includes the primary circuit consisting of the reactor, steam generators, primary pumps, the pressurizer and certain safety devices. This enclosure is closed by a dome and is internally covered with a welded steel sealing skin.

Powerful swing bridges or polar bridges are known made by the firm VEVEY. The known bridges each rotate on a circular track, inside the nuclear reactor building. This circular track is supported by a series of metal brackets integral with the aforementioned enclosure. It consists of a box girder on which a rail is fixed by toads. The radius of curvature of the track is guaranteed by a pre-centering of the rails in very tight tolerances.

The box beam is fixed to the brackets in a very specific manner in order to limit the horizontal forces between the track and the brackets during a variation in the diameter of the enclosure. These variations can be caused by prestressing, shrinking and bending, as well as the building test pressure and the effect of temperature.

Two supporting beams are connected to each other by two crosspieces, each resting on two bogies each comprising two rollers. A curved surface key, welded to the chassis of each bogie in its center, constitutes the support surface of the crosspiece.

The rollers have a slight taper ensuring a constant circumferential speed over the width of the rail. The entire bogie is slightly inclined to ensure good contact between the roller and the rail, which takes account of the deflection of the swing bridge under maximum load.

The rotary bridge is guided by pre-stressed horizontal rollers arranged at the four corners of the bridge. These rollers are independent of the bogies and integral with the crosspieces.

The rotation system is driven by four DC motors with constant separate excitation. They are coupled in series of two per side. Any offsets of the bridge are signaled to the driver by limit switch contacts of the pre-stressed guide rollers.

This known rotary bridge has the serious drawback of exhibiting a tendency to jamming and even of jamming after a sometimes relatively short operating time.

If the axle is off-center, the driver can center the bridge thanks to the fact that the latter is fitted with two independent static drives supplying the motors of the rotation system. These maneuvers are however difficult to execute. The bridge operator must then call on an authorized person to center the bridge. Despite this precaution, it sometimes happens that the bridge gets stuck and can only be released by means of pullers.

The present invention aims to remedy the above drawbacks. It relates to a revolving overhead crane made up of carrying beams connected together by connecting crosspieces to form a rigid rectangular frame bearing in the vicinity of each corner, on a girder base moving on a circular raceway, essentially characterized in that that it rests on each of the box springs by means of mobile lifting devices.

In a particular embodiment, the lifting device is a spherical support consisting of a ball joint and a unidirectional sliding plate with very low coefficient of friction.

According to a feature of the invention, each turning bed consists of a box carried by two axles and provided with rollers. One axle is mounted on a fixed bearing secured to the box, the other axle is movable relative to the box and is mounted on this box so as to be able to oscillate in a vertical plane around a longitudinal shaft perpendicular to the vertical plane passing through the movable axle.

Each swivel base is advantageously provided with two horizontal guide rollers ensuring the positioning of the latter on the raceway.

According to another particular feature of the invention, means for taking information relating to the positioning of the bridge are mounted at the level of each of the mobile supports mounted between the carrying beams and the swivel bases.

The aforementioned information acquisition means advantageously consist of potentiometric sensors for linear displacements.

The invention also relates to a method for controlling and adjusting the gyration synchronism of a rotary overhead crane, characterized in that information is taken of the positioning of the overhead crane at a mobile reference support.

In a particular implementation of the method according to the invention, the positioning of the overhead crane is controlled with respect to a reference bed base using a potentiometric linear displacement sensor which translates any deviation in analog voltage and d '' a delinearization and switching network which corrects the speed reference of the regulator.

Other details and particularities of the invention will emerge from the following detailed description of an embodiment of the invention illustrated, by way of nonlimiting example, by the appended drawings.

• - la figure 1 est une vue en plan du pont roulant tournant suivant l'invention et d'une partie du chemin de roulement circulaire;
• - la figure 2 est une vue en élévation latérale d'un sommier mobile;
• - la figure 3 est une vue en élévation latérale du pont montré à la figure 1;
• - la figure 4 est une vue en plan d'un sommier de giration du pont roulant tournant;
• - la figure 5 est une vue en coupe verticale suivant la ligne II-II' du sommier de giration montré à la figure 2;
• - la figure 6 est une vue de bout suivant la flèche X du sommier de giration montré aux figures 4 et 5.;
• - la figure 7 est un schéma synoptique du montage électronique de commande du moteur d'un des sommiers;
• - la figure 8 est un schéma électronique d'une des cartes d'un module électronique de commande auquel est raccordé un capteur de déviation linéaire;
• - les figures 9 et 10 illustrent deux formes possibles d'irrégularité dans le mouvement de giration du pont: déhanchement et déplacement du pont parallèlement à lui-même.

In these drawings:

• - Figure 1 is a plan view of the rotary traveling crane according to the invention and part of the circular raceway;
• - Figure 2 is a side elevational view of a movable bed base;
• - Figure 3 is a side elevational view of the bridge shown in Figure 1;
• - Figure 4 is a plan view of a swivel bed of the rotary traveling crane;
• - Figure 5 is a vertical sectional view along line II-II 'of the swivel base shown in Figure 2;
• - Figure 6 is an end view along arrow X of the gyration bed shown in Figures 4 and 5 .;
• - Figure 7 is a block diagram of the electronic control assembly of the motor of one of the bed bases;
• - Figure 8 is an electronic diagram of one of the cards of an electronic control module to which a linear deviation sensor is connected;
• - Figures 9 and 10 illustrate two possible forms of irregularity in the gyration movement of the bridge: wobbling and displacement of the bridge parallel to itself.

In these various figures, the same reference notations designate identical or analogous elements.

As illustrated in FIG. 1, the revolving overhead crane according to the invention consists of support beams 1 in boxes connected to each other by crossbeams 2 of connection in welded construction to form a rigid rectangular frame generally designated by the reference notation 3. This rigid frame 3 is supported in the vicinity of each corner on gyration bases 4 to 7 by means of mobile lift devices 8 to 11 consisting of spherical bearings (TETRON SF support) composed of a ball joint 12 allowing rotational movements up to 0.06 radian and a horizontal sliding plate 13 unidirectional up to 44.8 mm with very low coefficient of friction, -a sheet of plating 14 in stainless steel, a core 15 and a base 16 with a flat underside. The relatively low coefficient of friction is obtained by the insertion of a teflon band 17 loaded with glass fibers and glued to the core of the ball joint 12. This spherical support allows a good distribution of the weight and the load of the bridge rolling rotating on the four bed bases 4 to 7 while allowing horizontal displacements in the direction of the arrows Y. It provides the four bed bases 4 to 7 and the carrying frame with a freedom of oscillation relative to each other so to accept without tension the variations of the deflection of the bridge under maximum load.

A lifting trolley 18 fitted with redundant winches 19 and a rigorously vertical lifting reel 18 ′ travels along the above-mentioned carrying beams.

The four box springs 4 to 7 which carry the rotary traveling crane move on a circular raceway 20 arranged for example inside the confinement enclosure 21 of the nuclear reactor.

The raceway consists of a box beam 22 made of AE36 steel on which two rails 24 made of high strength steel are fixed by toads 23. The rails 24 are adjusted in the best conditions with epoxy injection ensuring perfect contact between the components. They are then machined to very precise tolerances by a mobile boring machine.

The box beam 22 is fixed to the brackets by means of hooped neoprene supports with epoxy injection between the adjustment systems.

This fixing system aims to limit the horizontal forces between the track and the brackets during a variation in the diameter of the enclosure. These variations can be caused by prestressing, shrinkage and creep, as well as the building test pressure and the effect of the sun or temperature.

Each turning bed 4 to 7 consists of a box 25, carried by two axles 26, 27, provided with rollers 28 one of which is motor and the other carrier. The rollers 28 have a slight conicity guaranteeing a constant circumferential speed over the width of the rail 24. The axes of the rollers are oriented towards the center of the bridge in order to guarantee correct rotational movement. The axle 26 is mounted on a fixed bearing 26 'integral with the box 25. The other axle 27 is movable relative to the box 25 and is mounted on this box 25 so as to be able to oscillate in a vertical plane around an axis longitudinal 29 perpendicular to the vertical plane passing through the axle 27. This ensures a homogeneous distribution of the load of each box spring on its four rollers 28 and a good contact between roller 28 and rail 24. A clearance 30 is provided on the side walls of the box 25 to allow pivoting of the other box. Each of the bed bases 4 to 7 is guided by two horizontal rollers 31 mounted on it. A horizontal guide roller 31 ′, integral with a cross member 2, guides the support frame 3. The total weight of the bridge is around 400 tonnes. The maximum hook load is 530 tonnes.

The drive motors 32 to 35 of each of the bases 4 to 7 are asynchronous motors with a ring of normal construction. The control equipment for these motors consists of thyristor variable speed drives 36, for example STATOVAR devices with four quadrants produced by the firm TELEMECANIQUE.

The variable speed drive 36 "STATOVAR 4 QUADRANTS" is generally used for movements with high maneuvering rates and up to high powers and speeds. It makes it possible to obtain progressive starts and decelerations and allows very reduced approach speeds for delicate positioning.

Regulation operation is obtained by adjusting the stator voltage and therefore the torque produced. This is modified by the variation of the conduction angle. The variation of the conduction angle thus makes it possible to modify the supply voltage of the motor and, consequently, its torque.

• - un bloc gradateur de puissance agissant sur la tension statorique, désigné dans son ensemble par la notation de référence 37;
• - un module électronique de commande désigné dans son ensemble par la notation de référence 38;
• - un ensemble électromécanique constitué de contacteurs de puissance et de contacteurs auxiliaires;
• - un ensemble d'organes périphériques.

This 36 "STATOVAR 4 QUADRANTS" variable speed drive includes:

• - a power dimmer block acting on the stator voltage, designated as a whole by the reference notation 37;
• - an electronic control module designated as a whole by the reference notation 38;
• - an electromechanical assembly consisting of power contactors and auxiliary contactors;
• - a set of peripheral organs.

The electronic control module 38 comprises a transformer 39 and three electronic cards 40 to 42 interconnected with one another.

The first of these cards is the elementary electronic card 40 (SF ₁ LK301) which groups together a supply circuit 43 rectified and filtered at + 26 V, a safety circuit 44 controlling the stabilized supply at 15 V, as well as the presence and the order of the phases and compliance with a speed threshold fixed at 130% of the nominal speed, an adaptation circuit 45 for the return signal corresponding to the stator current, a synchronization and ignition circuit.

• - un circuit d'adaptation du signal de retour tachymétrique, permettant de régler ce dernier à 10 V pour la vitesse nominale;
• - un circuit élaborant le signal de référence, avec réglage des vitesses maximales et des vitesses réduites de ralentissement dans les deux sens de marche;
• - un circuit de régulation avec amplification de l'écart, détection de son signe, transformation en valeur absolue, élaboration du signal de commande des allumeurs;
• - un circuit logique d'inversion validant par des signaux le gradateur qui doit être mis en action. Le choix dépend du signe de l'écart sauf dans les zones de marche en grande vitesse où le gradateur correspondant au sens moteur est maintenu en pleine conduction. Les signaux de validation sont asservis au signal du circuit de sécurité d'une part et à la position enclenchée du contacteur de ligne 46 d'autre part. En l'absence de signal de validation, la logique d'inversion délivre un signal qui bloque les impulsions d'allumage et ouvre la boucle de régulation;
• - un comparateur contrôle le ralentissement avant l'arrêt et délivre le signal de coupure du frein lorsque la vitesse est inférieure à 5% de sa valeur nominale;
• - un relais assure la sortie de la commande de frein sous la dépendance de la carte suivante.

The second elementary electronic card 41 (SF1LK302) has the main function of regulating the speed of the drive motor (s) 32 to 35. It includes:

• - a circuit for adapting the tachometric feedback signal, enabling the latter to be adjusted to 10 V for the nominal speed;
• - a circuit developing the reference signal, with adjustment of maximum speeds and reduced speeds of deceleration in both directions of travel;
• - a regulation circuit with amplification of the difference, detection of its sign, transformation into absolute value, elaboration of the igniter control signal;
• - a reversing logic circuit validating by signals the dimmer which must be put into action. The choice depends on the sign of the deviation except in high speed walking zones where the dimmer corresponding to the motor direction is kept in full conduction. The validation signals are slaved to the signal of the safety circuit on the one hand and to the engaged position of the line contactor 46 on the other hand. In the absence of a validation signal, the inversion logic delivers a signal which blocks the ignition pulses and opens the regulation loop;
• - a comparator controls the deceleration before stopping and delivers the brake cut-off signal when the speed is less than 5% of its nominal value;
• - a relay ensures the output of the brake control under the dependence of the following card.

The third electronic card 42 (SF ₁ LK304) has the main function of controlling the brake logic and rotor contactors 46. It has a ramp that can be adjusted separately for each direction of travel, the output of which remains blocked until the brake is applied. loose.

In order to ensure a perfect geometry of the turning movement and in particular to avoid decentring the above-mentioned rotary crane, the synchronization of the turning is checked, by adjusting the speed of at least one of the motors. 32 to 35 mounted on the turning bases 4 to 7.

To this end, an information acquisition is carried out on the positioning of the traveling crane at one of the mobile supports 8 to 11 carrying the crossmember provided with a horizontal guide roller 31 ′. This support is the mobile support of the reference bed base 4.

On the reference base 4, a potentiometric linear displacement sensor 47 determines the displacement of the fulcrum of the bridge with respect to the correct position, both in center search and in wobbling. This potentiometric sensor 47 is connected in series, in the elementary electronic card 41 SF ₁ LK302) of the electronic control device 38 to a potentiometer 48 and the assembly is adjusted so as to form a resistance of 800 Ohms between the connected wires. at terminals 51 and 65 of said SF ₁ card LK302, and introduces permanent information acting on the speed reference of the governor.

The contactors 46 are controlled by the electronic control module 38 to activate 1 to 4 sections of rotor resistors 46 ′ of ohmic value well determined for slip values to the motors adjusted as a function of the starting and braking characteristics.

Each dimmer 37 supplies the stators of two motors in parallel. Tachometric dynamos 49 to 52 are fitted to each motor 32 to 35. The voltages supplied are connected in series and regulate the speeds.

Each dimmer 37 is made up of three groups of 2 thyristors 53 to 62 mounted head to tail and possibly protected by overcurrent relays 63 to 66. Each group is connected in series with a stator phase.

A deviation of the actual bearing point of the reference support frame 3 from a fixed point, less than 10mm is negligible. The positioning of the support frame 3 relative to the reference base 4 is then considered to be correct.

The acceptable difference on the other bed bases is greater than that which can be accepted on the reference bed base 4. An anchoring device 67 retains the traveling crane in the event of an earthquake.

Endstops, not shown, causing the blocking of the port, for example, are provided at a distance of 56 mm for the reference base 4 and the neighboring base 5 while these distances can reach 100 mm for the two bases 6, 7 carrying the other connecting cross 2.

A predetermined difference in pulses reduces the speed reference of the regulator, driving the bed bases 4, 5 in advance until the return to the correct position.

The center of gyration is controlled by the sensor 47 mounted between the support beam 1 and the reference bed base 4, the sensor 47. translates a linear displacement in analog voltage, proportional to the difference and acting in correction on the speed reference, by the through a delinearization and switching network.

EXAMPLE 1

A first possible form of irregularity in the gyration movement of the bridge consists in the displacement of the box springs 6, 7 of one of the crosspieces 2 'of the support frame 3 while the box springs 4, 5 of the other crossbeam 2 remain fixed . Consider for example that the cross member 2 carrying in the direction indicated by the arrow Y the guide roller 32 remains fixed. A swaying causes the support points to move along the abscissa in the direction indicated by the arrow X. For a maximum allowed swaying of 300 mm (displacement BB '= 300 mm), the four corners of the rigid support frame will undergo the following displacements:

A movement in a direction outside the raceway is assigned the + sign. The sign of this displacement is - if displacement B B 'takes place in a direction internal to the raceway.

The deviation at point 1 corresponding to the reference base 4 will cause an elongation of the potentiometric linear deviation sensor.

If this elongation causes a deviation of the position of the movable fulcrum from the theoretical position greater than 10 mm, the potentiometric sensor 47 translates the linear displacement into analog voltage proportional to the difference. A positive movement increases the stator current and increases the speed of the drive motors 32 and 33 via a delinearization and switching network, controlling the bed base in advance until returning to the correct position.

EXAMPLE 2

A second possible form of movement of the rotary traveling crane is by simultaneous movement of the four bed bases 4 to 7 in the same direction Y. It is in fact a translation of the support frame 3 parallel to itself, for example during the inversion of the drive motors 32 to 33 of the bed bases 4, 5 of one of the crosspieces 2. This displacement may be desired for example to position the hook in the center of the building for certain delicate operations.

It can also be the consequence of an error due to the accidental reversal of the direction of travel of the drive motors 32, 33 or 34, 35 of the bed bases 4, 5 or 6, 7 of one of the cross members 2.

The maximum displacement allowed in translation is 200 mm and ordered. To this displacement correspond the following deviations of mobile supports on the abscissa:

The signs affected by the movements correspond to those of Example 1.

A positive movement increases the stator current and increases the speed of the drive motors.

On each of the bed bases, end of travel stops signal and possibly cause the immediate stop of the bridge after a displacement of 56 mm for the bed bases 4 and 5 and after a movement of 100 mm for the bed bases 6 and 7.

This system allows linear variations inherent in the construction of the raceway, thermal expansion, possibly the prestressing of the concrete of the wall of the enclosure which carries the raceway.

Compared to other known control methods, the method according to the invention provides information on the position of the rotating crane totally independent of the number of turns made by the above-mentioned bridge.

In addition, it allows the bridge to operate in translation over a distance of approximately 200 mm, while ensuring perfect regularity of the turning movement without off-center of the bridge. This translation allows to reach precisely the center of the reactor which corresponds to the center of the building and thus ensures the correct handling of the reactor vessel cover.

It is obvious that the invention is not limited to the details described above relating to a particular embodiment of a rotary overhead crane and that numerous modifications can be made to these details without departing from the scope of the invention.

Claims (12)

1. Rotating overhead crane consisting of load-bearing beams connected together by connecting crosspieces to form a rigid rectangular frame resting in the vicinity of each corner, on a girder base moving on a circular raceway, characterized in that it is supported on each of the bed bases (4 to 7), by means of mobile lifting devices (8 to 11). 2. Rotating traveling crane according to claim 1, characterized in that the lifting device is a spherical support consisting of a ball joint (12) and a unidirectional sliding plate (13) with very low coefficient of friction. 3. 'Revolving traveling crane according to any one of claims 1 and 2, characterized in that each gyration bed consists of a box (25) carried by two axles (26, 27) and provided with rollers ( 28), an axle (26) being mounted on a fixed bearing integral with the box, the other axle (27) being movable relative to the box (25) and being mounted on this box (25) so as to be able to oscillate in a vertical plane around a longitudinal shaft (29) perpendicular to the vertical plane passing through the movable axle (27). 4. Revolving overhead crane according to any one of claims 1 to 3, characterized in that each turning bed is provided with two horizontal guide rollers (31) ensuring the positioning of the latter on the raceway. 5. Revolving overhead crane according to any one of claims 1 to 4, characterized in that means for taking information relating to the positioning of the bridge are mounted at one of the mobile supports mounted between the carrying beams (1) and the turning bases (4 to 7). 6. A traveling crane according to claim 5, characterized in that the aforesaid information-taking means consist of potentiometric sensors (47) of linear displacements. 7. Rotating traveling crane according to any one of the preceding claims, characterized in that each box spring (4 to 7) is equipped with an alternating motor (33 to 35) of the three-phase asynchronous type with rings provided with control and control as well as safety devices. 8. A traveling crane according to claim 7, characterized in that the control means comprise a power dimmer block (37) with natural ventilation comprising thyristors (53 to 62), control circuits, current transformers ( 39) for the measurement of the stator current, an electronic control module and a set of peripheral members. 9. A traveling crane according to any one of the preceding claims, characterized in that the image voltage of the speed obtained is supplied by a tachometric dynamo (49 to 52) placed at the end of the motor shaft. 10. Method for controlling and adjusting the gyration synchronism of a rotary crane according to any one of the preceding claims, characterized in that an information acquisition of the positioning of the crane is carried out at the level of a mobile support. reference. 11. Method according to claim 10, characterized in that the positioning of the overhead crane is controlled with respect to a reference bed base (7) using a potentiometric sensor (47) of linear displacement which translates any deviation into analog voltage and a delinearization and switching network which corrects the speed reference of the regulator. 12. Method according to claim 11, characterized in that a predetermined difference in pulses reduces the speed reference of a regulator, driving a bed base in advance until the return to the correct position.

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