Patent Number: 043280714
Section: claims

1. A device for guiding ducts between a point of a component which is capable of rotational motion about a vertical axis and a fixed point located externally of said component, wherein said device comprises means for supporting the ducts between said fixed point located on the axis of rotation of said movable component and does not rotate with the latter, and means for guiding ducts between the second point and a third point located on the axis of rotation of said movable component and rotating with the latter, said third point being located at a given distance of said second point, said guiding means being adapted to maintain the ducts in uniformly spaced relation on a surface of revolution about the axis of rotation of said movable component whatever the rotation of the third point relative to the second point and to ensure uniform distribution of this rotation on said distance between the second and third point, so that the ducts form a bundle type assembly in said guiding means, said device further comprising means for securing the third point to said movable component. 2. A device according to claim 1, wherein said movable component is the small rotating shield plug of a nuclear reactor of the type which is closed at the top by a horizontal shield roof fitted with a large shield plug which is rotatable about the vertical axis thereof and with a small rotating shield plug arranged within said large rotating shield plug and displaced off-center with respect to said large rotating shield plug. 3. A device according to claim 2, wherein said means for supporting said ducts consist of two articulated arms, one arm being rigidly fixed to the upper extremity of said guiding means and the other arm being rigidly fixed to a stationary portion of said reactor. 4. A device according to claim 2, wherein said device comprises a hanger rigidly fixed to said small shield plug and comprising a vertical column and a horizontal arm, the free extremity of said hanger arm being located on the axis of said small rotating shield plug, a first horizontal guiding arm articulated at one extremity with respect to a fixed point of the reactor, a second horizontal guiding arm having one extremity which is pivotally attached to the free extremity of said first guiding arm, means for controlling the pivotal motion of the first arm with respect to the fixed point and the pivotal motion of the two guiding arms with respect to each other in such a manner as to ensure that the free extremity of said second guiding arm is caused to remain in the axis of said small rotating shield plug, the ducts aforesaid being fixed along said two guiding arms and along the horizontal arm of the hanger, and means for guiding portions of said ducts which are located between said hanger arm and said second guiding arm so as to maintain said portions of ducts in uniformly spaced relation on a ruled surface of revolution about the axis of said small rotating shield plug so that said portions of ducts thus form a bundle-type assembly. 5. A device according to claim 4, wherein the guiding means aforesaid consist of a plurality of circular plates forming a bottom guide-plate rigidly fixed to the extremity of the hanger arm, a top guide-plate rotationally coupled to the free extremity of the second guiding arm but capable of free vertical translational motion with respect to said second arm, and at least one intermediate guide-plate, the portions of ducts aforesaid being fixed at uniform intervals on the periphery of said guide-plates, and means for maintaining said guide-plate horizontal and centered on the axis of said small rotating shield plug, and means whereby the angle of rotation of the top guide-plate with respect to the bottom guide-plate at the time of pivotal motion of the guiding arms and of the rotating shield plugs is uniformly distributed between the guide-plates as a function of the vertical distances between said guide-plates, a degree of slack being left in the ducts between the top guide-plate and the second guiding arm. 6. A device according to claim 5, wherein said top guide-plate is rigidly fixed to the extremity of the second guiding arm by means of a variable-length unit which exerts a constant force directed along the axis of said small rotating shield plug and provides a rotational coupling. 7. A device according to claim 6, wherein the unit aforesaid is a jack having an operating rod disposed along the axis of said small rotating shield plug and rigidly fixed to said top guide-plate, the jack body being rigidly fixed to the extremity of said second guiding arm. 8. A device according to claim 5, wherein the guide-plates aforesaid are connected to each other by a plurality of cables having the same length, each cable being attached at the upper end thereof to the top guide-plate and at the lower end thereof to the bottom guide-plate, said cables being so arranged as to pass through the intermediate guide-plates aforesaid and being fixed on said plates. 9. A device according to claim 4, wherein the hanger aforesaid is in turn capable of rotational motion about the vertical axis of its column by means of an actuating unit. 10. A device according to claim 9, wherein said vertical column is stationary and wherein said hanger arm is pivotally mounted at the upper extremity of said vertical column, the portions of ducts which extend along said column being attached to the periphery of the second circular guide-plates which are similar to the first guide-plates, said second top guide-plate being rigidly fixed to said arm by means of resilient devices which produce a force in the vertical direction, a degree of slack being left in the ducts between said second top guide-plate and said hanger arm. 11. A device according to claim 10, wherein said guiding means consist of a plurality of circular plates forming a bottom guide-plate coupled directly to the small rotating shield plug, a top guide-plate rotationally coupled to the free extremity of the second guiding arm but capable of free vertical translational motion with respect to said second arm, and at least one intermediate guide-plate, the portions of ducts aforesaid being fixed at uniform intervals on the periphery of said guide-plates, and means for maintaining said guide-plates horizontal and centered on the axis of said small rotating shield plug, and means whereby the angle of rotation of the top guide-plate with respect to the bottom guide-plate at the time of pivotal motion of the guiding arms and of the rotating shield plugs is uniformly distributed between the guide-plates as a function of the vertical distances between said guide-plates, a degree of slack being left in the ducts between the top guide-plate and the second guiding arm. 12. A device according to claim 11, wherein said top guide-plate is rigidly fixed to the extremity of the second guiding arm by means of a variable-length unit which exerts a constant force directed along the axis of said small rotating shield plug and provides a rotational coupling. 13. A device according to claim 11 or claim 12, wherein the guide-plates aforesaid are connected to each other by a plurality of cables having the same length, each cable being attached at the upper end thereof to the top guide-plate and at the lower end thereof to the bottom guide-plate, said cables being so arranged as to pass through the intermediate guide-plate or guide-plates aforesaid and being fixed thereon. 14. A device according to claim 2 or claim 3, wherein the guiding means aforesaid consist of a vertical guiding mast rigidly fixed at the lower end to the center of the small rotating shield plug and at the upper end to the free extremity of the supporting means, a horizontal top guide-plate rotationally coupled to the free extremity of said supporting means but capable of free vertical translational motion and increasing said mast, a horizontal bottom guide-plate encircling said mast and rigidly fixed to the lower end of said mast, and at least one intermediate guide-plate encircling said mast and capable of free translational motion in the direction of said mast, said intermediate guide-plate being partially free for rotational motion about said mast, each guide-plate being provided at the periphery with uniformly spaced means for fixing the cables aforesaid, the intermediate guide-plate or each intermediate guide-plate being provided with means for limiting rotational displacement about the mast so as to ensure that the angle of rotation between the top guide-plate and the bottom guide-plate is uniformly distributed between the intermediate guide-plate or plates. 15. A device according to claim 14, wherein the means for limiting said angle of rotation consists of at least one key rigidly fixed to the mast in cooperating relation with at least one recess having the desired length and formed in the periphery of the central orifice of the intermediate guide-plate. 16. A device according to claim 14, wherein the means for limiting said angle of rotation consist of a ring which is coupled for translational motion with said guide-plate and the external periphery of which is provided on the one hand with at least one recess of given length in cooperating relation with at least one stud rigidly fixed to said intermediate guide-plate qnd on the other hand with at least one recess of given length formed on the internal periphery of said ring and adapted to cooperate with a key which is rigidly fixed to said mast.