Patent Number: 047553499
Section: description

As seen in FIG. 1, the lower part 1 of the pump, not represented in its entirety, is a cylinder of revolution around a vertical axis 2, and, at a certain distance from its lower end, there is an integral peripheral annular flange 3 with rectangular cross section, which is installed in an annular socket 4. Socket 4 is closed at the top by a cover 5, likewise annular, which is held fast by bolts or similar devices, only whose axes 6 have been represented, and which cover surrounds the pump base 1 with a certain play. A damping ring 8 encircles the flange 3, and its external diameter is much smaller than the internal diameter of the socket 4. This arrangement permits horizontal displacements of the flange 3, attached to the pump base, with respect to the socket 4. The socket 4 can slide with a little play within a cylindrical reinforcement 7a of the dome 7. This cylindrical section must be firm with the dome in the horizontal direction. Conversely, in the axial direction, the play between the flange 3 and the socket 4 is very small, so that the two elements are practically solidly fixed to one another in this direction. The ring 8 (see FIG. 2) has at its outer edge two projections 9, diametrically opposite one another, and each terminated by a flat end 10, which bears against a plane surface projecting from the internal lateral surface of the socket 4. On its interior edge, it has two projections 11, diametrically opposite one another, and at 90.degree. from the projections 9, each terminated by a flat end 12 which bears against a flat section arranged in the external lateral surface of the flange 3. This arrangement delimits between the damper ring 8 and the socket 4 two essentially semi-annular chambers C1 and C2, diametrically opposite one another, and between the ring 8 and the flange 3, two chambers C3 and C4, similar to C1 and C2, but displaced from them by 90.degree.. Furthermore, the interior edge of the socket 4 is extended downward by a cylindrical skirt 13, flared at the bottom to a truncated cone 14, and terminated at its periphery by an integral collar 15 having an exterior surface formed with an annular groove which receives a metallic journal 16. This journal is pressed against a cylindrical bearing 17, connected to the internal wall of the dome 7 by a horizontal ring 18. Finally, flat grooves with keys, represented in FIG. 2, prevent any rotation of the damping mechanism. In this installation, the heat-carrying fluid, for example molten sodium, circulates downward in the pump (arrow F1) and can rise between the dome 7 and the pump base 1 through suitably calibrated passages, which can be orifices or grooves, arranged in the journal 16 (arrow F2) and in the periphery of the socket 4 (arrow F3). The functioning of the above described damping mechanism is as follows: Axial movements of the pump within the dome 7 (arrow F4) are permitted by sliding of the collar 15 within the skirt 17 which is firm with the dome 7 and by sliding of the socket 4 within the internal cylindrical reinforcement of the dome 7. As regards relative horizontal (radial) movements between the pump and the dome, they are accommodated by sliding of the annular flange 3 within the socket 4, which is firm with the dome in the horizontal direction, with a maximum possible displacement d equal to the difference between the internal diameter of the socket 4 and the external diameter of the damper ring 8. The chambers C1 and C2 permit radial movements along one principal axis, and chambers C3 and C4 permit movement along a second principal axis. During an earthquake, for example, when abrupt displacements occur in the direction of the first principal axis, as from C1 toward C2, the connection between the pump 1 and the dome 7 compresses the liquid trapped between the dome 7 and the ring 8 due to shifting of the elements acted upon, which in turn causes displacement of the ring 8. The trapped liquid does not have time to escape between these elements to accommodate the displacement (in contrast to what occurs in the case of slow displacements, resulting, for example, from differential thermal expansions). The ring 8, in contact with the pump through the intermediary of the flange 3, thus displaces the pump base 1 in the direction from C1 to C2. Still in the case of abrupt displacements, this time in the direction from C3 to C4, the ring 8, in mechanical contact with the connection between the pump and the dome, receives the dome's displacment directly. Thereupon, the ring 8 compresses the fluid confined within the chamber which is situated between it and the pump in the direction of displacement, thus communicating its displacement to the pump. The chambers diametrically opposite those which are compressed, for their part undergo a depressurization, and add their damping force to that of the chambers which are compressed. In the case of a displacement in an arbitrary direction, for example at 45.degree. with respect to the principal axes, the chambers C1, C2, C3 and C4 act simultaneously. Finally, in slow movements due to thermal expansions in a horizontal plane (radial movements), the adjustments between the various elements cause sufficient escape of fluid to avoid the effects of compression and decompression of the chambers in question. This circumstance enables displacements without constraint of the pump with respect to the dome. The same holds for vertical (axial) movements, with the flowing fluid being easily able to traverse the passages arranged at the periphery of the socket 4. In the embodiment represented in FIG. 3, elements identical to those of FIGS. 1 and 2, or playing the same role, have been given the same designations. The damper ring 8 is replaced by several fluid-escape damping mechanisms 20, four in number, for example, commonly known as "dashpots." Dashpots 20 are equidistant from one another and are installed radially between the socket 4 and cavities arranged in the flange 3. Dashpots are, of course, conventional and will therefore not be described here in detailed fashion. It will suffice to indicate that in the illustrative embodiment of the invention, they each comprise a cylinder 21 lodged within a corresponding cavity of the flange 3, a piston 22, a valve for supply of high pressure to the piston body, with the piston pressed toward the exterior of the cylinder 21 and the free end of the piston bearing against the internal lateral wall of the socket 4, and one or more escape orifices or grooves 23. The cylinder 21 and the piston 22 delimit a chamber 24, which in the present case, is filled with liquid sodium, and opens into the socket 4 which is filled with this fluid. During abrupt displacements, due, for example, to earthquakes, the connection between the pump and the dome compresses the molten sodium contained within the chambers 24. This fluid cannot rapidly escape through the calibrated orifices or grooves 23 and blocks the pistons 22 from closing the chambers 24. Conversely, in the case of slow displacements resulting from differential thermal expansions in a horizontal plane, the fluid can flow through the orifices or grooves 23, without restraining the displacement between the pump and the dome. The lower portion of the connection between the pump base 1 and the dome 7 is of the same design as in the previous embodiment.