WO2020047684A1

WO2020047684A1 - Device and system for three-dimensional vibration insulation

Info

Publication number: WO2020047684A1
Application number: PCT/CL2018/050080
Authority: WO
Inventors: José Luis ALMAZÁN CAMPILLAY; Sergio Ignacio REYES ARRIAGADA
Original assignee: Pontificia Universidad Catolica De Chile
Priority date: 2018-09-04
Filing date: 2018-09-04
Publication date: 2020-03-12

Abstract

The invention relates to a device for three-dimensional vibration insulation between structures or equipment and the foundations thereof, which comprises: a hinged hexagonal metallic frame formed by an upper plate for anchoring to the structure; a lower plate for supporting on the foundations and at least one pair of hinged arms oppositely inclined at each side; one or more vertical elastomer compression rings in series, confined between the upper plate and a vertical cylindrical support tube joined to the lower plate; at least one pair of elastomer traction bands in front of and behind the frame, which are fastened on, and pre-tensioned between, a pair of the hinged arms on each side; and a central guide bar joined to the upper plate and unrestrictedly inserted into a flexible annular bushing inserted into the cylindrical tube. Three or more devices combined in a structure form a three-dimensional vibration insulation system.

Description

DEVICE AND SYSTEM FOR THREE-DIMENSIONAL VIBRATION INSULATION

FIELD OF THE INVENTION

The present invention refers to a device for the three-dimensional isolation of vibrations between structures and industrial equipment in general and the ground or its foundations and more specifically for the three-dimensional isolation of vibrations of small, medium or high intensity and to be used in conjunction with other similar devices, thus forming a three-dimensional vibration isolation system.

STATE OF THE ART

The most common three-dimensional (3D) vibration isolation devices that exist to protect industrial structures and equipment from earthquakes and other small, medium and high-intensity vibrations comprise a central element that works in compression and absorbs vertical vibrations combined with one or more Auxiliary mechanisms that provide insulation in the two horizontal directions.

An example is the base seismic isolator disclosed in JPH10280660A has as its main elements an air spring between an upper plate connected to the floor of an insulation floor and a lower plate connected to foundations through a mounting plate and a pair friction dampers. The air spring has inside, approximately in the center, a rubber block that regulates the lower limit position of the upper plate. Friction dampers consist of two articulated arms arranged on either side of the spring and having adjustable friction pads on the joint. In addition, the bottom plate is supported by a flat bearing that is movable in two dimensions along the surface of the mounting plate, preventing the device from deforming under horizontal loads. The device is designed to be part of a system with other equivalent devices distributed on the insulation floor to absorb vertical vibrations in combination with a number of compression and tension springs arranged between the insulation floor and foundations to absorb deformations or horizontal efforts.

There are also some 3D vibration isolators that integrate the elements that allow efforts or deformations to be absorbed in all the directions and not only vertically. An example is the vibration isolator for an electrical connection panel disclosed in patent KR10708215B1. The vibration isolator comprises a central spring arranged between an upper plate and a lower plate, the upper plate being attached to an upper base which is in turn attached to the lower part of the electrical panel and the lower plate being attached to a lower base in contact with the ground. In addition, the vibration isolator comprises a flexible bar through the center of the spring, in which both the central spring and the flexible bar absorb shocks when the ground vibrates vertically and, in turn, flex elastically to allow tension springs (they can be three, four or more), arranged at an angle between the upper plate and the lower plate and articulated at their ends, damp the horizontal and vertical vibrations of the floor transmitted to the electrical panel and restore it to its original position. Due to its spring-based construction, it does not have an energy dissipation mechanism in itself.

Another integrated 3D vibration isolator is that of Chilean invention patent No. 52,267 (Almazán et al.), Which is characterized by being formed by a frame of six metal plates connected by hinges that form a hexagonal frame, with a horizontal upper plate attached to a connecting element attached above to the structure or equipment, a lower plate attached to the foundations and a pair of lateral plates inclined on each side that guide the vertical movement of the upper plate due to the weight characteristic of the structure and vibrations and at the same time of restriction to movements in the longitudinal axis and twists in the transverse axis, the device also having at least one spring that limits the relative movement between the plates and provides the rigidity of the device and at least one energy sink that dampens the relative movement of the plates. The connecting element is pivotable with respect to an axis of rotation of direction parallel to the transverse axis of the device, the transverse axis being defined as the horizontal axis perpendicular to the hinges. The restriction of rotation around the vertical axis is provided by fixing the bottom plate to the foundations of the structure or equipment

The Almazán et al. It is designed to configure a system that gathers a set of devices for three-dimensional isolation of vibrations in respective discrete supports of an industrial equipment or structure, it being enough that the structure to be isolated has 3 or more discrete supports, and that each device is oriented so that the transverse axes of each one converge to the vertical axis that crosses the center of gravity of the structure, thereby achieving isolation both vertically and laterally. It has the advantage that it takes up little space and has a high power dissipation and vertical deformation capacity (up to 300 mm) at a low cost. However, it suffers from a series of limitations: • the deformation capacity is limited by allowable tension of the spring steel;

• not easily scalable to larger equipment or structures (over 2 ton load) due to cost in materials (steel volume);

• works in combination with other devices with specific orientations;

• requires a pivotable connecting element between the device and the equipment or structure to be isolated;

• the shear stress in the device is supported by an articulated hinge system, which work only in its longitudinal direction, which is why only half of the devices resist shear stresses during an earthquake; Y

• uses an energy sink to dampen the relative movement of the plates, making the insulating device more expensive.

Consequently, it would be desirable to be able to overcome the above limitations and provide a three-dimensional vibration isolator that is simpler and more efficient, has a broader application spectrum, is scalable to higher loads, and is more economical to manufacture.

SUMMARY OF THE INVENTION

The present invention consists of a device for the three-dimensional (3D) isolation of vibrations between structures or industrial equipment in general and the ground or its foundations, comprising an articulated hexagonal metal frame formed by an upper plate for anchoring to the structure or equipment, a bottom support plate on the ground or foundations and at least one pair of articulated and oppositely inclined arms on each side. Inside the frame, one or more vertical compression elastomeric rings are arranged centrally and vertically in series confined between the upper plate and a vertical cylindrical tube that serves as a lower support for the elastomeric ring (s) as a whole and that is attached to the bottom plate. Furthermore, at least one pair of elastomeric traction bands is arranged in front and behind the frame, in which each elastomeric traction band is hooked on, and pre-tensioned between, a pair of articulated and oppositely inclined arms on each side of the framework. The device further comprises a central guide bar of a predetermined length less than the gap between the top plate and the bottom plate, which has one end attached to the top plate, passes through the interior of the vertical compression elastomeric ring (s) and through the The opposite end is inserted unrestrictedly into a flexible ring bushing that is fixedly inserted into the vertical cylindrical tube. Applied to an industrial structure or equipment, the device is combined with at least two other equivalent devices to form a 3D vibration isolation system made up of at least three non-aligned devices arranged on respective discrete supports of the industrial structure or equipment. isolate.

Vertical compression elastomeric rings may have metal plates between the rings.

Regarding the number of articulated and oppositely inclined arms and the number of elastomeric traction bands, the device admits different combinations of them, depending on the desired performance, the weight of the structure or equipment to be supported and the number of devices that make up the system. Preferably, the device has only one pair of elastomeric traction bands, the bands respectively located in front of and behind the hexagonal metal frame hooked on, and pre-tensioned between, a pair of articulated and oppositely inclined arms on each side of the frame. However, the device could also have two or more pairs of articulated and oppositely inclined arms per side and the elastomeric traction bands being hooked on one or more of said pairs of arms per side, in order to increase the rigidity of the assembly before more structures heavy.

The supports for the elastomeric traction bands can be extensions of the articulation axes of the oppositely inclined pairs of articulated arms or metal bars orthogonally attached to the arms.

The different components of the device are assembled in such a way that it works as a vertically flexible and laterally rigid support, thus generating a rotation-based three-dimensional isolation mechanism (rocking), where the central guide bar slides inside the flexible bushing void in response to vertical vibration and then return, giving the device vertical restoring force. The guide bar also prevents buckling of the elastomeric ring or rings and acts by supporting the cutting effort. When the device is combined with other devices to isolate a structure or industrial equipment from vibrations, the shear stress is simultaneously supported and distributed among all the guide bars.

For small lateral deformations the device has a certain flexibility given by the properties of the flexible ring bushing, however for large deformations it reaches its limit by restricting movement and transferring lateral forces through the cylindrical tube. The flexible ring bushing can be an elastomeric bushing or a polymeric bushing and allows the upper plate to rotate avoiding the need to materialize an external ball joint.

By replacing the steel compression and traction springs of the devices of the prior art, in particular of the device of Chilean invention patent No. 52,267 (Almazán et al.), With elastomers, a greater deformability and versatility are obtained for Scaling the device to heavier structures and reducing the cost of materials for manufacturing. Furthermore, due to the energy dissipation source of the elastomers, an auxiliary energy dissipation device can be dispensed with. Likewise, the non-linear force-deformation ratio of elastomers is more suitable for seismic isolation since its hardening at large deformations is gradual, functioning as a displacement limiter. However, it is possible to use metal springs and vertical compression elastomeric rings in combination to achieve the desired behavior, specifically one or more coaxial metal coil springs, of the same height and different diameter, arranged outside it or the elastomeric rings vertical compression.

On the other hand, when replacing the pivotable connecting element that exists in Almazán et al. Between the isolation mechanism and the structure or equipment, by the central guide bar and the restriction structure formed by the vertical cylindrical tube and the flexible ring bushing, the invention serves both to isolate from small high-frequency vibrations and to isolate from large vibrations produced by intense earthquakes. Thus, the device of the invention can be used in conjunction with other devices that are the same as a vibration isolation system in various equipment that requires it, having the advantage of also providing protection during seismic events.

Some examples are:

• Large mass and cost air conditioning equipment ("Centrifugal Liquid Chiller"), generally located on upper floors of buildings where ground accelerations are amplified.

• Electric generators that could be critical for necessary operations after a seismic event.

• Rotary equipment with high mass in general

Also, the device of the invention can be used in conjunction with other similar devices as a low cost seismic isolator for industrial structures such as: • Thin-walled stainless steel tanks with legs for storing wine or other substances

• Pressure vessels for industrial processes such as digesters and distillation towers

• Wood structures

• Electrical substation equipment in general

BRIEF DESCRIPTION OF THE FIGURES

In order to facilitate the understanding of the foregoing ideas, the object of the invention is described below, referring to the accompanying illustrative drawings.

Figure 1 represents a perspective view of an embodiment of the three-dimensional vibration isolation device of Chilean invention patent No. 52,267 (Almazán et al.), Which constitutes the prior art closest to the invention.

Figure 2 represents a perspective view of an embodiment of the three-dimensional vibration isolation device of the invention.

Figure 3 represents an exploded perspective view of the device of Figure 2, showing the different elements that compose it.

Figures 4.1 and 4.2 represent front elevation views of the three-dimensional vibration isolation device of Figure 2 under two conditions, respectively, one normal (without applied loads) and the other deformed under the simultaneous action of the proper weight of the structure or equipment and loads due to vertical and horizontal vibrations, the latter in the lateral direction of the device or, what is the same, in the (frontal) plane of the figure.

Figures 5.1 and 5.2 represent side views of the three-dimensional vibration isolation device of Figure 2 in the same two situations as in Figures 4.1 and 4.2 but in which the horizontal vibrations are in the front-to-back direction or, which is the same , in the (lateral) plane of the figure.

Figure 6 represents an example of application of the three-dimensional vibration isolation device of the invention mounted under the four legs of a liquid container tank. DETAILED DESCRIPTION OF THE INVENTION

As seen in Figure 1, the three-dimensional vibration isolation device of Chilean invention patent No. 52,267 (Almazán et al.), Which constitutes the closest prior art to the invention, is characterized first by comprising an isolation mechanism consisting of: i) a frame of six metal plates, one upper (1) horizontal, one lower (2) horizontal and two pairs of inclined side plates (3) on each side, in which the plates are connected by means of hinges ( 4); ii) a vertical direction primary compression spring (5) centered between the upper and lower plates and horizontal direction secondary tension springs (6) extending between the side plates on either side of the device; and iii) a vertically directed frictional hysteretic energy sink (7) located within the vertical spring between the top and bottom plates.

Here the primary spring is in charge of providing the basic stability of the device and providing the necessary flexibility so that the device can function as a vibration isolator and the secondary springs are in charge of controlling the deformation by its own weight.

Furthermore, this device of Figure 1 comprises a connecting element (8) between the isolation mechanism and the structure or equipment, arranged on the upper plate (1) pivotably with respect to a direction of rotation axis parallel to the transverse axis ( T) of the device and consisting of a support platform (8a) pivotably connected to the top plate (1) by an axis (8b) supported on a pair of supports (8c). The vertical (V) and longitudinal (L) axes of the device mentioned above are also indicated.

Figures 2 and 3 show an embodiment of the three-dimensional vibration isolation device (10) of the invention where the articulated hexagonal metal frame formed by an upper plate (20), in this case circular, a lower plate ( 30), also circular, and a pair of oppositely inclined articulated arms (90) on each side, all joined by flat joints (120). Inside the frame there is a vertical compression elastomeric ring (40), confined between the upper plate and a cylindrical support tube (80) that is attached to the lower plate and has an annular flexible bushing (70) inserted inside it . More specifically, the vertical compression elastomeric ring is confined upperly by the upper plate (20) and lowerly by a flange (100) protruding orthogonally from the upper edge of the cylindrical tube (80) and serving as a support platform for the ring. A central guide bar (60) that is attached to the top plate, passes through the interior of the vertical compression elastomeric ring and, through its free end, enters the flexible bushing without restriction. cancel. Two pairs of horizontal elastomeric traction bands (50) extend between the pair of oppositely inclined arms (90) that make up either side of the hexagonal metal frame, so that one pair extends in front of the frame and the other behind of the frame and they are hooked on its internal face by metal bars (1 10) attached orthogonally to each arm and tightened.

Figures in Figures 4.1 and 4.2 show front elevation views of the device of the invention in the non-deformed (Fig. 4.1) and deformed (Fig. 4.2) state. It can be seen that when the device is deformed, the vertical elastomeric compression ring (40) compresses due to the effect of a vertical force, increasing its cross section and in turn allowing the upper plate (20) to rotate due to the effect of a force on the horizontal direction. For its part, the horizontal elastomeric traction bands (50) lengthen, reducing their cross section. Note that the top plate (20) can rotate in the (front) plane of the figure due to three factors: (i) the flexural deformability of the vertical compression elastomeric ring (40); (ii) the flexural deformability of the annular flexible bushing (70); and (iii) the rotational capacity in the frontal plane of the joints (120).

Figures 5.1 and 5.2 show a side elevation view of the device in the non-deformed (Fig. 5.1) and deformed (Fig. 5.2) state, in which when the device is deformed and, as in Fig. 4.2, the vertical elastomeric compression ring (40) is compressed by the effect of a vertical force and the upper plate (20) is rotated by the effect of a force in the horizontal direction. Note that the top plate (20) can rotate in the (lateral) plane of the figure due to three factors: (i) the flexural flexibility of the vertical compression elastomeric ring (40); (ii) the flexural flexibility of the annular flexible bushing (70); and (iii) the existing mechanical play in the joints (120).

Applied to the seismic protection of a liquid storage tank with legs, as shown in Figure 6, it is necessary to have a device (10) in each leg. The lower part of the pond legs or supports are rigidly linked, by means of anchor bolts or welding, with the upper plate of the device (10). Under the action of the own weight of the pond, and of horizontal and vertical forces produced by environmental vibrations (such as an earthquake, for example) the structure can move vertically and rotate like a rigid body around a horizontal axis that passes through its base ( rocking), thus acting as an isolation system both vertically and laterally. This movement is possible thanks to the great vertical deformation capacity of the device, and the rotational capacity of the upper plate.

Claims

one . Device (10) for the three-dimensional isolation of vibrations between industrial structures or equipment in general and the ground or its foundations, CHARACTERIZED because it comprises:

an articulated hexagonal metal frame consisting of:

an upper plate (20) for anchoring to the structure or equipment;

a bottom plate (30) for support on the ground or foundations; Y

at least one pair of articulated and oppositely inclined arms (90) on each side; one or more vertical compression elastomeric rings (40) arranged centrally and vertically in series confined between the upper plate (20) and a cylindrical vertical tube (80) of lower support, which is attached to the lower plate (30);

at least one pair of elastomeric traction bands (50) respectively located in front and behind the hexagonal metal frame, in which each elastomeric traction band is hooked on, and pre-tensioned between, a pair of the articulated and oppositely inclined arms on each frame side; Y

a central guide bar (60) of a predetermined length, less than the gap between the top plate and the bottom plate, having one end attached to the top plate, passes through the interior of the vertical compression elastomeric ring (s) and through the The opposite end is inserted unrestrictedly into an annular flexible bushing (70) which is fixedly inserted into the vertical cylindrical tube.

2. The device according to claim 1, CHARACTERIZED in that it comprises at least two vertical elastomeric compression rings arranged vertically in series with metal plates between them.

3. The device according to claim 1, CHARACTERIZED in that it comprises two pairs of elastomeric traction bands (50) respectively located in front and behind the hexagonal metal frame, which are hooked on, and pre-tensioned between, metal bars (1 10 ) orthogonally joined to the articulated arms and oppositely inclined (90).

4. The device according to claim 1, CHARACTERIZED in that it comprises a pair of elastomeric traction bands (50), respectively located in front and behind the hexagonal metal frame, hooked on, and pre-tensioned between, extensions of the joint axes ( 120) of the articulated and oppositely inclined arms (90).

The device according to claim 1, CHARACTERIZED in that the vertical cylindrical tube (80) has a support platform for the vertical compression elastomeric ring (s) (40) as a whole, which is constituted by a flange (100) protruding orthogonally from the upper edge of the vertical cylindrical tube.

6. The device according to claim 1, CHARACTERIZED in that the one or more vertical compression elastomeric rings (40) are combined with one or more coaxial, helical, metal springs of the same height and of different diameter, arranged outside of it or vertical compression elastomeric rings.

7. System for the three-dimensional isolation of vibrations between structures or industrial equipment in general and the ground or its foundations, CHARACTERIZED because it comprises at least three devices (10) according to claim 1, not aligned with each other and arranged in respective discrete supports of the industrial structure or equipment.