DE102018009356A1 - Omnidirectional liquid column damping system - Google Patents

Abstract

The invention relates to a liquid column damping system, in particular for damping vibrations, preferably structural vibrations, comprising a tank filled with a liquid, in which spaced-apart, preferably vertical columns (S1, S2, S3) of the tank, in particular for forming communicating liquid columns, by a for all pillars (S1, S2, S3) are connected to the common base region (B) of the tank, in which the tank comprises at least three pillars (S1, S2, S3) and each pillar (S1, S2, S3) at its lower end into one own horizontally extended arm (A1, A2, A3) merges into the common base area (B).

Description

The invention relates to a liquid column damping system, in particular a semi-active liquid column damping system, which can be used for damping vibrations, for example for damping structural vibrations (for example buildings, onshore and offshore wind turbines) or also for damping vibrations of other objects.
comprising a tank filled with a liquid, in which spaced apart, preferably vertical columns filled with the liquid, in particular partially filled columns of the tank are connected by a common base region of the tank, in particular as a result of which liquid columns communicating with the columns are formed.

The common base area is to be understood here as such an area via which the lower ends of the columns are connected to one another, in particular in the horizontal direction. In the sense of the invention and according to the known prior art, it is the area in which the liquid flows from and to each column meet and / or mix. This area ensures fluid communication between the columns.

In the prior art, for example, are from the publication US 970,368 Passive-type liquid column damping systems are known and are based in their operating principle on the fact that, in the event of vibrations, the liquid present in the liquid column damping system, such as a Newtonian liquid, is moved and energy dissipation takes place due to the turbulence effects and the local pressure losses due to friction that occur in the liquid column or in the base area of the tank with the vibrations.

The basic principle of such a liquid column damping system is also referred to as a Frahm roll tank in recognition of the technology that goes back to the inventor Frahm. Such a tank operating according to this basic principle also forms the subject of the present invention.

The usual arrangement of such liquid column damping systems is such that two vertical columns are provided which are connected at their lower ends by the common base region. A tank that makes up such a liquid column damping system thus has a U-shape and a specific direction of action, which corresponds to the direction of distance between the columns. With such a system, only vibrations which correspond to this direction of action can be effectively damped.

Versions of such a system have also become known in the prior art, which include means for adjusting the damping and / or the natural frequency of such a liquid column damping system. Such means include, for example, orifices in the base region of the tank, which restrict the flow between the columns through the base region of the tank to a greater or lesser extent depending on the degree of opening, and for example means for adjusting the column cross section. For example, names the publication DE 10 2013 010 595 A1 the same applicant, such a system, but which also has only a single direction of action.

In order to be able to dampen vibrations which are in directions perpendicular to one another, it is known, e.g. two such previously described systems with mutually perpendicular directions of action in the same structure to be protected, e.g. to provide a building, which makes the construction complex and expensive.

The document JP 2000-018322 names a version in which a tank comprises four columns, two of which are opposite each other. The direction of connection of the one pair of opposite columns is perpendicular to the direction of connection of the other pair. All columns are hereby connected to a common base area, the pillars at their lower ends connecting directly and without deflection to the top of the common base area, ie the base area is located under all the columns of this tank.

This publication states that it is advantageous that this liquid column damping system can be used to dampen vibrations which lie both in the connecting direction of the one pair of opposing columns and in the connecting direction of the other pair of opposing columns. According to this publication, the system therefore works bidirectionally in two directions of action which are perpendicular to one another.

The problem with the known systems is that they have no omnidirectional effect, in particular these systems cannot be tuned in terms of any desired or required horizontal direction of action in terms of damping and / or natural frequency.

It is therefore an object of the invention to provide a liquid column damping system that corresponds to the above-mentioned construction with several columns, which, however, in more than only two directions of action, in particular omnidirectional, that is to say can be used in all possible horizontal directions of action, and preferably that it can be set in several directions and preferably omnidirectionally with regard to damping and / or natural frequency.

According to the invention, this object is achieved in that the tank comprises at least three columns and each column at its lower end merges into its own horizontally extended arm, which opens into the common base area.

Contrary to the prior art, the invention thus provides that the vertical columns do not directly connect to the common base area. Such a direct connection leads to the disadvantage in the prior art that the flows from the columns mix directly at the lower end of the columns and their directional information and the restoring action required to reduce the vibrations are thereby lost. A direct connection of the columns to the common base area also prevents the flow damping and / or the natural frequency of the system from being set in a direction-dependent manner. In order to be able to reduce vibrations omnidirectionally, however, damping and / or frequency parameters must be adjusted depending on the direction, because the dynamic effects, particularly in the event of earthquakes, wind and wave loads, always require different system parameters for the damping systems, depending on the direction of action.

In contrast, in the invention, a respective column transitions from the vertical direction at its lower end into the horizontal direction of the respective arm belonging to the column, e.g. through a pipe section bent at right angles. There is therefore a horizontally directed flow within the arm, namely in the direction of connection between the lower end of the column and the common base region, which preferably forms the center or a central region of the damping system in which all the flows come together.

Depending on the direction of vibration, the flow in the differently oriented, but in each case horizontal arms of the several columns is of different sizes. The size of the flow in relation to the direction of the arms is proportional to the vectorial splitting of the exciting vibration into the directional components, which are defined by the arm directions.

A liquid column damping system according to the invention thus provides the possibility, compared to the prior art, of damping vibrations in all directions. The effect is thus omnidirectional in the invention.

In one possible embodiment of the invention, an arm that is assigned to a column and connects it to the base region can have a length that corresponds at least to the height of a respective vertical liquid column. The constructive selection that an arm between the base area and the column has a length that can at least correspond to the height of the column can ensure that the arm is always longer than the height of the liquid in the column.

A respective arm can preferably extend in a straight line in its extension between the column and the base region. In another version, an arm can also have a non-linear course, e.g. have a curved course, e.g. with a part-circular bend.

The invention can preferably provide that an adjustable damping element, in particular one that can be adjusted with an actuator, is arranged in each arm of a respective column, with which the free flow cross section of the respective arm can be adjusted. Such a damping element can e.g. be a flap pivotable about an axis. A damping element can generally be designed as a valve actuator with which the free flow cross section of a respective arm can be changed between a maximum and a minimum. E.g. a slide valve or ball valve arrangement can also be used. In this way, damping can be set individually for each of the several flow directions in the arms, in particular what would not be possible within the common base area, because any damping measure at this location would have the same effect on all flow directions.

Due to the individual adjustability of the damping in each of the directions given by the multiple arms, an overall effective damping of the system according to the invention can be optimized for every possible direction of an exciting vibration.

The invention can provide directions of vibration, e.g. a structure (for example a building) in which such a system is used to be measured using at least one sensor and to automatically change the damping in the individual arms as a function of the detected direction of vibration, in particular in such a way that the damping is optimized for the detected direction .

A control and / or regulation can be provided for this purpose, which generates control signals from the recorded vibration data with which Actuators are actuated, which adjust the damping elements in the arms.

The invention can preferably also provide for each column to be divided in the vertical direction, in particular in the swivel-out area of the liquid, preferably over the entire length of the column, into a plurality of chambers lying parallel to one another in the vertical direction, at least a partial number of all chambers, possibly all of the chambers comprises a valve element, in particular a valve element adjustable with an actuator, with which the liquid flow into and out of the respective chamber can be restricted and / or shut off.

The effective cross-section of each column can be varied by optionally locking or unlocking one or more chambers and thus influencing the natural frequency of the system depending on the direction. The chambers of each column preferably have at least partially different cross sections, in particular so that a variety of different cross sections of the respective column can be set by varying the unlocked and locked chambers.

The invention can provide that the named valve element of a respective chamber is arranged at the upper end of the chamber and that the free cross section of the chamber to the surrounding atmosphere can be varied, in particular shut off, with the valve element. In this way it can be determined whether the respective chamber is part of the communicating volume of the respective column or not. Each valve element can preferably be switched with an actuator at least between the maximally closed position, preferably the shut-off position and the maximally open position, in particular intermediate positions can also be adjustable.

The preferred subdivision of the column cross-section into chambers also stabilizes the liquid movement in the columns by preventing the formation of waves by dividing the liquid surface into smaller areas. In contrast to the prior art (e.g. JP 2000-018322 ) ensure that the liquid movement in the columns mainly takes place only in the vertical direction. As a result of the subdivision, the liquid in the columns cannot move in the horizontal direction in the event of an oscillation, or can move only slightly deviating from the connection direction between the column and the base region. By preventing sloshing effects on the otherwise possible waves, the vibration frequency of the damper and thus the overall effect can be stabilized.

The invention can provide that the actuators are controlled by a control / regulation, in particular the same aforementioned control / regulation as a function of a measurement-related oscillation of the structure in which the system is used, in particular so that the natural frequency as a function of the set detected frequency of the vibration.

The invention can also provide that a fill level sensor is arranged on at least one pillar, in particular each pillar, with which the current fill level of the liquid in the pillar and / or the liquid movement in the pillar, in particular in a chamber that cannot be closed to the surrounding atmosphere, is preferred is dynamically measurable. The damping in each arm and / or the effective column cross-sections can also be changed depending on the determined fill levels of each column.

Overall, this results in a semi-active changeability of the system parameters of a liquid column damping system according to the invention, in particular the natural frequency and the damping as a function of the recorded vibration data, preferably the direction and the frequency of the vibration. The system can thus also be measured in-situ on a vibration measured e.g. by earthquakes, wind and wave loads, preferably optimize the system parameters depending on the direction.

In a preferred constructive embodiment, the invention can provide that the horizontally extended arm of each column is designed to extend in a straight line between the lower end of the column and the common base region, in particular in the radial direction with respect to a common point, in particular a common center point in the common base region, around which the columns are arranged around.

When arranged around a center point, the arms can preferably all have the same length. The columns are all arranged on the same circle around the center. Basically, the arms can also have different lengths.

In a further preferred embodiment, the invention can provide that the inner cross section of the arm of each column is at least substantially the same size as the inner cross section of the column, in particular up to a maximum deviation of plus / minus 20%, preferably plus / minus 10%. Columns and arms can thus also be formed from the same tubular element which has a bend, in particular a 90 degree bend, at the transition between the column and arm.

Furthermore, the internal cross sections of all columns and arms of a tank of the system according to the invention can be the same, in particular up to a maximum deviation of plus / minus 20%, preferably plus / minus 10%.

To optimize the vibration behavior, the inner cross sections of the columns and arms can also be designed differently. This allows the maximum flow velocities in columns and arms to be influenced in a targeted manner.

A preferred embodiment can provide that the arms are arranged radially in a star shape around the base region, in particular the center thereof, preferably all in a horizontal plane. The columns can preferably be arranged on a common circle around a point, in particular around a center point or around an axis, in particular a vertical center axis, in the base region. In particular, the columns can all have the same radial distance from the center / center axis. This center of the base area then forms the center of the entire system.

The arms, and thus also the columns, preferably have the same angular distance from one another.

In a first preference, the invention can provide that at least half of all columns have no column opposite in the direction of their arm. In contrast, the embodiment is particularly preferred if each arm has an extension, in particular a straight extension in a different direction. In this particularly preferred embodiment, there is therefore no column which is directly opposite another column in the direction of extension of its arm or, in other words, there are no two arms whose direction of extension is identical or parallel. This ensures that all directions of vibration are damped equally efficiently without preferring certain directions of vibration.

For example, this can be achieved if the number of columns and arms is odd for the same angular distance between the columns and / or arms.

A particularly simple constructive embodiment of the invention can e.g. provide that a tank of the system comprises exactly three columns with respective arms, which are arranged at an angular distance of 120 degrees around the base area, in particular the center thereof.

Exemplary embodiments of the invention are explained below with reference to the figures.

The and show in two different views a structurally particularly preferred embodiment of the invention. The tank of the liquid column damping system here comprises the three columns S1 , S2 and S3 that refer to the connection point of a vibrating structure or object that is assumed to be horizontal 10th are aligned vertically. However, such a vertical alignment is not absolutely necessary for the invention. Inside every pillar S1 , S2 , S3 there is therefore a vertical flow direction 4th the liquid, eg water or oil.

At the bottom of each column S1 , S2 , S3 this goes with respect to the center of the system M in a radial arm A1 , A2 respectively. A3 about. This respective arm connects the respective pillar with the common base area B that around the center M is trained around.

In each of the arms A1 , A2 , A3 is a valve element 6 , arranged here in the form of a rotatable orifice, with which the free flow cross-section in the respective arm A1 , A2 respectively. A3 can be changed. These valve elements 6 can close to the base area B be arranged, but are within the arms.

In this version it is between the neighboring arms A1 , A2 respectively. A2 , A3 respectively. A3 , A1 , each included an angle of 120 degrees. All arms are the same length, so the columns S1 , S2 , S3 all lie on the same circle.

Every pillar S1 , S2 , S3 is still in the vertical direction in several chambers 7 divided what into 3rd is visualized in more detail. At least a part number of all chambers 7 has a closable valve element at the upper end of the chamber or column 13 on, here in the form of a lid, with actuators 14 are adjustable about horizontal axes of rotation, in particular between an open and a closed position.

There is a level sensor in a chamber that cannot be closed 8th arranged with which the liquid level in the chamber or the column can be measured dynamically.

It is a control system, for example using a computer 12 provided that in is indicated. Here are the sensors, for example the level sensor via cable 16 and at least one vibration sensor 11 connected as well as the actuators of the valve elements 13 of the chambers 7 and the damping elements 6 in the arms.

One with the at least one sensor 11 detected vibration of the building or object, in particular their direction and / or frequency are evaluated in the control and, depending on the determined direction and / or frequency, the damping in the arms and / or the natural frequency by controlling the actuators of the damping elements 6 or the actuators 14 be changed. In particular, the damping can be optimized with respect to the direction of the vibration and the natural frequency of the system with regard to the vibration frequency. This adjustment can be made in-situ when an event occurs, for example earthquakes, wind and wave loads.

By splitting the flow due to the vibration into the directional components, which correspond to the directions of the arms A1 , A2 and A3 Correspondingly, there is the possibility of influencing the damping and natural frequency of the system depending on the direction and thus optimizing the system omnidirectionally.

The shows examples of the preferred embodiments of systems according to the invention in supervision, essentially the arms A1 , A2 , A3 , .... and A9 can be seen at the outer ends of the columns are arranged upright.

All versions of the described to and the are characterized by the fact that for the configurations shown there the columns are evenly arranged on a circle around a center and all arms around the center point in different directions. There are no two arms that are on the same axis or have parallel directions. As a result, the total number of columns or arms for these preferred configurations always results in an odd number of columns and arms, for example 3rd , 5 , 7 , 9 , ....

Although designs whose columns are distributed unevenly or at least two arms lie on a common axis and thus point in the same direction are not excluded from the invention, they are not preferred. In these configurations, at least one direction of vibration is always damped more unevenly than the other directions of vibration.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 970368 [0003]
• DE 102013010595 A1 [0006]
• JP 2000018322 [0008, 0026]

Claims (15)

Liquid column damping system, in particular for damping vibrations, preferably structural vibrations, comprising a tank filled with a liquid, in which spaced-apart, preferably vertical columns (S1, S2, S3) of the tank, in particular for forming communicating liquid columns, by one for all columns (S1 , S2, S3) common base region (B) of the tank, characterized in that the tank comprises at least three columns (S1, S2, S3) and each column (S1, S2, S3) at its lower end in its own horizontal extended arm (A1, A2, A3) merges into the common base area (B). Liquid column damping system after Claim 1 , characterized in that the horizontally extended arm (A1, A2, A3) of each column (S1, S2, S3) is designed to extend between the lower end of the column (S1, S2, S3) and the common base region (B) is rectilinear, in particular in the radial direction with respect to a common point, in particular a common center (M) in the common base region (B) around which the columns (S1, S2, S3) are arranged. Liquid column damping system according to one of the preceding claims, characterized in that an arm (A1, A2, A3) between the base region (B) and the column (S1, S2, S3) has a length which is at least the height of the column (S1, S2 , S3). Liquid column damping system according to one of the preceding claims, characterized in that the internal cross section of the arm (A1, A2, A3) of each column (S1, S2, S3) is at least substantially the same size as the internal cross section of the column (S1, S2, S3), in particular except for a maximum deviation of plus / minus 20%, preferably of plus / minus 10%. Liquid column damping system according to one of the preceding claims, characterized in that the inner cross sections of all columns (S1, S2, S3) and arms (A1, A2, A3) are the same, in particular up to a maximum deviation of plus / minus 20%, preferably plus / minus 10%. Liquid column damping system according to one of the preceding claims, characterized in that the internal cross sections of all columns (S1, S2, S3) and arms (A1, A2, A3) are of different sizes. Liquid column damping system according to one of the preceding claims, characterized in that each column (S1, S2, S3) is divided into a plurality of chambers (7) in the vertical direction, preferably over the entire length of the column, with at least a partial number of all chambers (7) being a valve element (13), in particular comprises a valve element (13) adjustable with an actuator, with which the liquid flow into and out of the respective chamber (7) can be restricted and / or shut off. Liquid column damping system after Claim 7 , characterized in that the valve element (13) of a respective chamber (7) is arranged at the upper end of the chamber (7) and with the valve element (13) the free cross section of the chamber (7) to the surrounding atmosphere can be varied, in particular shut off. Liquid column damping system after Claim 7 or 8th , characterized in that a level sensor (8) is arranged on at least one column, with which the level of the liquid in the column (S1, S2, S3) and or the vertical liquid movement in the column (S1, S2, S3), in particular can be measured in a chamber (7) which cannot be closed to the surrounding atmosphere. Liquid column damping system according to one of the preceding claims, characterized in that in each arm (A1, A2, A3) of a respective column (S1, S2, S3) an adjustable, in particular adjustable with an actuator damping element (6) is arranged, with which the free Flow cross-section of the arm (A1, A2, A3) is adjustable. Liquid column damping system according to one of the preceding claims, characterized in that the columns (S1, S2, S3) on a common circle around a point, in particular around a center point (M) of the damping system or around an axis, in particular a vertical center axis in the base region (B) are arranged uniformly, preferably with the same angular distance between the columns (S1, S2, S3). Liquid column damping system according to one of the preceding claims, characterized in that the arms (A1, A2, A3) are arranged radially in a star shape around the base region (B), in particular its center (M), preferably with the same angular distance, each arm being an extension, in particular has a straight extension in another direction. Liquid column damping system according to one of the preceding claims, characterized in that the number of columns (S1, S2, S3) and arms (A1, A2, A3) is odd. Liquid column damping system according to one of the preceding claims, characterized characterized in that the arrangement of columns (S1, S2, S3) and their arms (A1, A2, A3) is uneven around the base region (B). Liquid column damping system according to one of the preceding claims, characterized in that it comprises exactly three columns (S1, S2, S3) with respective arms (A1, A2, A3), preferably straight-line arms (A1, A2, A3) of equal length, with one Angular spacing of 120 degrees around the base area (B), in particular the center (M) thereof.

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