Vibration-insulating device and system

Abstract

Device for three-dimensional vibration insulation between structures or industrial equipment in general and the foundations thereof, comprising a hexagonal framework formed by six plates connected so as to pivot in relation to each other by horizontal parallel hinges, at least a spring and a damper being arranged between the plates. The device further comprises a connector arranged its series on the upper plate so as to pivot about a horizontal axis perpendicular to the axis of the hinges. The insulating system comprises a plurality of devices operating in parallel and oriented in such a way that the transverse axes thereof (defined by the hinges) converge onto a vertical axis that contains the center of gravity of the structure or equipment being insulated, in particular against high-intensity seismic activity with large displacements.

Claims

1. Device for three-dimensional vibration insulation between structures or industrial equipment in general and the foundations thereof, in particular structures or equipment with discrete supports, the device to be used together with two or more of other similar devices on equal number of discrete supports of the structure or equipment, characterized in that said device comprises: an insulation mechanism comprised of: a frame of six metal plates, an upper horizontal one, a lower horizontal one and two pairs of inclined lateral plates at each side, which configure the mantle of an hexagonal prism supported on one of its faces on the foundations, the plates are connected by hinges or other connectors forming a mechanism with three degrees of freedom: (i) displacement in the vertical direction; (ii) displacement in the direction transverse to the line of connection of the plates; and (iii) rotation about an axis along the line of connection of the plates, the three degrees of freedom being restricted, (i) with respect to displacement along the line of connection of the plates; (ii) with respect to rotation about an axis; transverse to the line of connection of the plates and (iii) with respect to rotation about an axis in the vertical direction; at least one spring arranged for limiting the relative movement of the plates; and at least one energy damper for damping the relative movement of the plates; and a connecting element between the insulation mechanism and the structure or equipment, arranged on the upper plate so as to pivot about a rotation axis parallel in direction to the transverse axis of the device, the transverse axis being defined as the horizontal axis perpendicular to the hinges.

2. The device of claim 1, characterized in that said at least one spring comprises one or more vertical direction compression spring located between the upper and lower plates, or at least one torsion spring arranged between the lateral plates of one side of the device and the lateral plates of the other side of the device, or a combination thereof.

3. The device of claim 1, characterized in that the at least one energy damper is hysteretic or viscous type damper.

4. The device of claim 3, characterized in that the hysteretic energy damper is a friction or metal yielding damper.

5. The device of claim 3, characterized in that the energy damper is a vertical axis damper located between the upper and lower plates.

6. The device of claim 3, characterized in that said at least one spring comprises one or more vertical direction compression spring and said energy damper is located in the interior of at least one vertical direction compression spring.

7. The device of claim 4, characterized in that the frictional energy damper is a torsion damper, arranged on the axes of the hinges or located on at least one pair of plates and connected to each other by a flexible element.

8. The device of claim 3, characterized in that at least one energy damper is a horizontal axis damper and extends inside or on the contour of the frame between the lateral plates of one side of the device and the lateral plates of the other side of the device.

9. The device of claim 5, characterized in that said device additionally includes one or more, horizontal axis damper and torsion dampers.

10. The device of claim 4, characterized in that the energy damper comprises a metal friction bar of prismatic cross-section connected to the upper plate and brushable against brake shoes arranged at the end of pivotable metal posts, and two horizontal direction tensile springs which extend between the posts externally to the friction bar.

11. The device of claim 1, characterized in that the connector includes a support platform for the structure to insulate, mounted on, pivot flat ball joint or hinge.

12. A system for three-dimensional vibration insulation between structures or industrial equipment in general and the foundations thereof, in particular structures or equipment with discrete supports, characterized in that said system comprises three or more devices according to claim 1 on equal number of supports of the structure or equipment, each device arranged with its transverse axis converging onto the vertical axis that passes through the centre of gravity of the structure or equipment.

Description

DESCRIPTION OF THE FIGURES

(1) To facilitate the understanding of the precedent ideas, the object of the invention is hereinafter described with reference to the accompanying illustrative drawings.

(2) FIG. 1 represents an isometric view of a preferred embodiment of the generic insulation vibration device of the invention showing the different elements that make it up.

(3) FIGS. 2.1 to 2.3 represent the assembly of 4 devices like the ones of FIG. 1, without showing the horizontal tensile springs for better clarity, the devices being arranged on a liquid storage tank of 4 legs, thus forming an example of vibration insulation system according to the invention.

(4) FIGS. 3.1 to 3.2 respectively represent an elevation view and an isometric view of an energy damper according to a preferred embodiment of the invention.

(5) FIGS. 4.1 to 4.4 show the theoretical results of tests with the device of FIG. 1.

(6) FIG. 5 shows the results of cyclic compression tests with the system of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

(7) The following elements are distinguished with reference to the figures: 1. Lateral plate 2. Upper plate 3. Lower plate 4. Hinge 5. Vertical compression spring 6. Horizontal tension spring 7. Energy damper 7a Friction bar 7b Metal post 7c Brake shoe 7d Tensile spring of the energy damper 7e Pivot axis of the posts 8. Connector 8a Support platform 8b Axis of the connector 8c Rotational support of the axis of the connector V vertical axis T transverse axis L longitudinal axis G vertical axis that passes through the centre of gravity

(8) As shown in FIG. 1, the device of the invention can be broken down into four parts. The first one is the central core of the device, comprised of the upper (1) and lower (2) plates, the vertical compression spring (5) and the energy damper (6). The second part is the movement guidance and restriction mechanism comprised of the lateral plates (3), which are connected to each other and with the upper and lower plates by means of hinges (4); this guidance mechanism restricts the displacement in the direction of the longitudinal axis L and the rotation about the transverse axis T. The third part, which is optional, is comprised of the two horizontal tensile springs (6), which connect the lateral plates (3) at the mid plane of the device. Finally, the fourth part is formed by a connector (8), which in this case is constituted by a support platform (8a) pivotally joined to the upper plate (1) by an axis (8b) supported on a pair of springs (8c). In summary, the first three parts of the device constitute the insulation mechanism itself and the fourth part is the connecting mechanism between the device and the structure.

(9) The vibration insulation system according to the invention illustrated in FIGS. 2.1 to 2.3 is an illustrative example of how a set of four vibration insulation devices according to the invention for a structure, in this case a liquids containment cylindrical tank with four legs, can be arranged and can act in cooperative manner. The four vibration insulation devices (A1, A2, A3, A4) are arranged on the supports of the liquids tank in such a way that the transverse axes (T1, T2, T3, T4) of each device converge onto the vertical axis (G) that passes through the centre of gravity of the structure, in this case coincident with the vertical axis of symmetry of the cylindrical tank, while the longitudinal axes (L1, L2, L3, L4) of the devices are in a direction tangent to the ground plan of the tank.

(10) In FIG. 2.1 the system is in a state of equilibrium, with the vertical springs pre-compressed by the effect of the empty tank's own weight. When a lateral force (P) is applied to the tank, now full of liquid, as shown in FIG. 2.2, the vertical compression springs of the second device (A2) and fourth device (A4) work together, deforming (FIG. 2.2) as the upper plate of the second device (A2) is displaced downwards and the upper plate of the fourth device (A4) is displaced upwards and at the same time rotate with respect to the longitudinal axes (L2, L4), and a rotation (R) is generated of the connectors of the first device (A1) and the third device (A3), and therefore of the tank. The vertical springs of the first and third devices (A1, A3) in FIG. 2.2 remain compressed solely by the effect of the tank's own weight and of the liquid they contain. Naturally, the horizontal tensile springs (not shown) deform correspondingly.

(11) Forming part of the main components of the insulator is the energy damper (7). In a preferred embodiment of the invention illustrated in FIGS. 3.1 and 3.2 the energy damper is a friction mechanism that is installed inside the vertical spring (5) and comprises a metal friction bar of prismatic cross-section (7a) that is connected to the upper plate (1) and it brushes against brake shoes (7c) arranged in the end of pivotable metal posts (7d). The friction force is controlled by means of the pre-tensioning of two tensile springs (7b) which act thanks to the post's pivoting capability. This allows generation of a friction force of constant magnitude, dissipating energy as the device vertically deforms. Therefore, it is possible to modify the equivalent damping of the system by changing the stiffness or pre-tension of the springs.

(12) Test Results

(13) FIGS. 4.1 to 4.4 show in a schematic way the theoretical components of the force-deformation relation of the exemplary device of FIG. 1. The contributions of the primary (vertical) spring, of the friction force in the energy damper and of the secondary (horizontal) spring are presented in FIGS. 4.1 to 4.3. The total force of the device is presented in FIG. 4.4. It should be noted that for deformations of up to 12.5% of the maximum deformation, the horizontal spring contributes with more stiffness than the vertical spring, while for larger deformations this relation is inverted. It is important to mention that similar force-deformation relations can be obtained with helical torsion springs.

(14) The prototype previously described as exemplary embodiment of application that FIGS. 2.1 to 2.3 show was tested in laboratory tests, obtaining the results shown in FIG. 5 where the force-deformation curves obtained are presented both experimentally (E) and analytically (T) through a finite elements model of the device, it can be appreciated that a vertical load of approximately 1000 kgf and a vertical tangent stiffness of approximately 9.25 kgf/mm are reached. The maximum vertical force that is observed at the end of the load cycle is due to the device being tested until the vertical frictional damper reached a maximum deformation of 50 mm. Since the model is scalable, this same design taken to real scale would reach a maximum deformation of up to 300 mm. Note that the energy dissipation by friction is very significant, reaching a damping factor equivalent to a approximately 30%.

(15) Although the description that is herein made pertains to a exemplary embodiment of the invention applied to a tank of liquids, it will be obvious to an expert in the field that the device can be used in other applications and even be used directly without connector in structures with continuous supports.