FR3117394A1 - INTELLIGENT VIBRATION DAMPER AND VIBRATING EQUIPMENT FOR THE PRODUCTION OF CONCRETE PRODUCTS EQUIPPED WITH SUCH A DAMPER - Google Patents

Abstract

The invention relates to a vibration damper (1, 10, 100) allowing continuous monitoring of the operation of vibrating equipment with which it is associated, said damper comprising a body (2) made of elastic material with a longitudinal axis (XX' ) interposed between two rigid disks (3, 4), characterized in that it comprises at least one measuring element (5, 5A, 5B) of the vibration frequency, of the amplitude and/or of the acceleration of movement and the force exerted on the damper by the vibrating equipment when the latter is equipped with said damper, said measuring element (5, 5A, 5B) being mechanically coupled to the elastic body (2). Abstract Figure: Fig.2

Description

INTELLIGENT VIBRATION DAMPER AND VIBRATING EQUIPMENT FOR THE PRODUCTION OF CONCRETE PRODUCTS EQUIPPED WITH SUCH A DAMPER

TECHNICAL FIELD OF THE INVENTION

The invention relates to a vibration damper allowing continuous control of the operation of vibrating equipment with which it is associated, said damper comprising a body of elastic material, with a longitudinal axis, interposed between two discs.

The vibration damper according to the invention is intended in particular, but not exclusively, to be implemented with vibrating equipment used for the manufacture of concrete products, for immediate or delayed demoulding.

STATE OF THE ART

In the particular case of concrete products, the vibration applied to the concrete in the fresh state plays a major role in the quality of the products obtained. The absence or lack of vibration as well as an excess of vibration can have negative impacts on the resistance and aesthetics of the product obtained. The vibration must be applied evenly over the entire volume of the concrete, otherwise it will create heterogeneities both within and on the appearance of the product obtained.

Defects on vibrated concrete products can be of various origins. “Vibrated concrete products” means concrete products that have been subjected during their production to at least one vibration operation. Deficiencies related to vibrations applied by vibrating equipment can be one of the origins of defects observed on vibrated concrete products. These deficiencies may be occasional, cyclical or permanent and may themselves result from an interaction of several other faults which are themselves occasional, cyclical or permanent.

In order to maintain a constant quality of production of vibrated concrete products and reduce the production scrap rate of the latter, it is therefore essential to continuously monitor certain parameters of the production tool and in particular the vibrating equipment. Wear of the elastic suspensions of the vibrating table, heterogeneity of the vibration movements during the filling of the mold or the compacting of concrete are, for example, all deficiencies that can lead to defects in the vibrated concrete products.

The majority of production deficiencies do not appear suddenly during production. They first impact the quality of the products in an irregular and periodic manner, the defect becoming more accentuated and becoming recurrent and visible only after a certain number of production cycles. One of the issues is therefore the real-time monitoring and control of deficiencies during the product production cycle.

In order to respond to this problem, it is known to use measurements from appropriate sensors placed in strategic locations of the vibration production tool and to carry out checks during the production cycles in this way.

Patent application EP3313634, in the name of the Applicant, proposes such a solution. It thus proposes a device for controlling the operation of a vibrating press during the process of producing concrete products for immediate release, said vibrating press comprising a mold defining at least one cell into which the concrete to be compacted is poured, said device control being remarkable in that it comprises a board, intended to be arranged under the mould, provided with means for measuring the frequency of vibration, the amplitude and/or the acceleration of movement, and/or the force exerted on said board during the production of concrete products. Concerning the management of defects only for vibrating presses. The presence of measuring means placed directly on an element involved in the production process, in this case the board, makes it possible to control the vibrating press in real time and to diagnose any malfunctions of the latter, if necessary.

The solution proposed in the aforementioned application, although satisfactory, nevertheless has limitations in that the board equipped with the measuring means is the only existing control and diagnostic tool, in that it is solely dedicated to vibrating presses and in that it only allows a spot check. No continuous control of the vibrating press is ensured between the production of two successive layings. While it can provide specific information on the quality of the vibration, it does not allow continuous monitoring of production quality and alerting as soon as a deficiency appears.

The invention aims to remedy these problems by proposing a measuring device making it possible to control and quickly alert the operator of any deficiencies in any equipment using vibration.

The invention thus aims to propose a vibration damper allowing continuous monitoring of the operation of vibrating equipment with which it is associated in order to have a panel of information providing information not only on the quality of vibration but also on the condition of the organs of the entire production system.

The invention also aims to provide equipment for the production of concrete products equipped with at least one such vibration damper.

OBJECT OF THE INVENTION

To this end, and according to a first aspect, the invention proposes a vibration damper allowing continuous monitoring of the operation of vibrating equipment with which it is associated, said damper comprising a body of elastic material, with a longitudinal axis, interposed between two rigid discs. The damper is remarkable in that it comprises at least one element for measuring the frequency of vibration, the amplitude and/or the acceleration of movement and the force exerted on the damper by the vibrating equipment when the latter is equipped with said damper, said measuring element being arranged in the damping and mechanically coupled to the elastic body.

The integration of one or more measuring element(s) placed in a component involved in the vibration process, in this case a vibration damper, allows continuous and permanent monitoring of the vibrating equipment to which it is associated in real time, i.e. during the production of concrete products, and thus to diagnose, if necessary, any malfunctions thereof. This permanent monitoring of the vibration thus makes it possible to have a panel of information providing information not only on the quality of vibration but also on the state of the organs of the entire production system. Thus directly integrated into the structure of said damper, the measuring element makes it possible to guarantee permanent and sufficient control of the overall operation of production equipment with which it is associated and by permanent and continuous control of all the equipment using to vibration, to increase control over the production of vibrated products and to anticipate the detection of recurring defects.

The integration of measuring element(s) within the damper makes it possible to overcome the problems of location, measurements and endurance of the equipment encountered with measuring elements placed on the vibrating equipment, in the vicinity of the shock absorber.

The shock absorber thus arranged constitutes an intelligent shock absorber.

According to a particular embodiment, the measuring element has a coaxial arrangement with the elastic body.

Advantageously, the measuring element is located at one of the ends of the elastic body.

Advantageously, provision may be made for the vibration damper to comprise two measuring elements arranged respectively on either side of the ends of the elastic body.

Advantageously, at least one of the measuring elements is encapsulated in one of the discs.

According to another embodiment, the elastic body comprises a first vibration absorber element and a second vibration absorber element aligned along the longitudinal axis, the measuring element being interposed between said first and second vibration absorber elements.

According to another embodiment, the elastic body delimits within it a cylindrical receiving chamber in which the measuring element is housed.

Advantageously, the measuring element is a force sensor. Other measurement means known per se (accelerometer) can of course be implemented without departing from the scope of the invention.

Advantageously, the damper comprises means for communicating the data recorded by the measuring element to a data acquisition and/or processing unit. It can be provided that the unit is embedded in the shock absorber or that it is independent of the latter.

Advantageously, the shock absorber comprises a module for storing the data detected by the measuring element. Like the data acquisition and/or processing unit, provision may be made for the storage module to be embedded in the shock absorber or for it to be independent of the latter.

Advantageously, the vibration damper comprises means for heating the elastic body.

Advantageously, the discs are connected together by a motorized screw in order to pre-stress the shock absorber.

According to a particularly advantageous embodiment, provision may be made for the damper to provide a quantified alert of a fault observed in relation to reference values of the expected operating cycle, said reference value constituting a benchmark to which reference is made to quantify and qualify the defect.

The invention also relates to vibrating equipment for the production of concrete products equipped with at least one vibration damper as described above. The equipment thus equipped with such damping, it is possible to follow the operating state of its components and, in the event that a malfunction is detected, to identify the zone at the level of which the malfunction takes place. .

The invention also relates to an installation for the production of concrete products using vibrating equipment equipped with dampers, at least one of which is a vibration damper as described above. The installation advantageously comprises means for recording the production and wear parameters, recorded during the manufacturing process of the concrete products, the said parameters comprising the data recorded by the measuring means of the damper(s) concerned (s).

BRIEF DESCRIPTION OF FIGURES

Other objects and advantages of the invention will appear during the following description, made with reference to the appended drawings, in which:

there shows a schematic view of a damper according to a first embodiment;

there shows a longitudinal sectional view of the shock absorber of the ;

there represents a variant embodiment of the ;

there shows a schematic view of a damper according to a second embodiment;

there shows a schematic view of a damper according to a third embodiment;

there illustrates graphs of measurements recorded with measurement systems implemented in the state of the art and a vibration damper according to the invention.

For greater clarity, identical or similar elements of the different embodiments are marked with identical reference signs in all of the figures.

DETAILED DESCRIPTION OF FIGURES

In relation to FIGS. 1 and 2, a first embodiment of a vibration damper according to the invention is described.

The shock absorber 1 comprises an elastic body of longitudinal axis XX' provided at each of its ends with a rigid disc 3, 4. The elastic body 2, forming a single piece made for example of rubber or elastomer, has advantageously a tubular shape to allow the passage of a through screw 8. The damper 1 is arranged to allow its connection to vibrating equipment with which it is associated, such as for example a table, an easel, a plate, a mould. It is of course obvious that the implementation of the damper 1 is not limited to such equipment, their use being able to be extended to any level of an installation as soon as dampers are provided. The damper 1 can be a Silentbloc® type damper.

The damper 1 also comprises an arrangement of one or more elements for measuring the frequency of vibration, the amplitude and/or the acceleration of movement and the force exerted by the vibrating equipment to which the damper 1 is associated. The measuring element advantageously comprises at least one force sensor placed within the damper 1 itself, either in a cavity provided for this purpose, or directly encapsulated in one of the component parts of the damper. The measuring element is mechanically coupled to the elastic body 2.

In what follows, the measuring element will be referred to interchangeably below as "sensor 5" or "measuring element".

In the embodiment illustrated in Figures 1 and 2, the sensor 5 is encapsulated in one of the discs 3 of the shock absorber 1. In the example shown, it is the upper disc.

Disc 3, preferably metallic, comprises two rigid annular assembly plates 30, 32 enclosing two rigid annular plates 31, 33, superimposed on one another and assembled together. The annular plates 31, 33 are arranged to define between them a receiving chamber 34 in which the sensor 5, of annular shape, is housed. The annular plates 31, 33 are subsequently referred to as sensor support plates

Disc 3, formed by assembly plates 30, 32 and superposed sensor support plates 31, 33, is fixed to elastic body 2. In order to accompany the movement of elastic body 2 during the damping phases, the sensor ring 5 is mounted to slide axially relative to the screw by means of a tubular guide piece 6. Annular seals 7, continuous or discontinuous, are arranged between the sensor 5 and each of the sensor support plates 31, 33 in order to dampen the stresses exerted on the damper 1 during its operation.

There illustrates a variant embodiment of the . In addition to the characteristics previously described, the damper 1 comprises means for driving the screw arranged between two plates 40, 42 forming the lower disc 4. In the example illustrated, the drive means comprise a heating resistor 9 presenting in the form of a plate or a spiral housed in a cylinder, associated with a gearmotor 11. Coupled to the through screw, the gearmotor 11 drives the screw to force the damper 1.

• chauffer l’amortisseur avant ou pendant la mise en vibration. Un amortisseur n’a en effet pas le même comportement oscillatoire selon sa température. A froid les oscillations sont moins amples qu’à chaud. De ce fait, à froid, on assiste en production soit à l’augmentation volontaire de la durée de vibration au détriment de la productivité, soit à l’apparition de défaut sur le produit.
• pré-contraindre l’amortisseur. Cela permet ainsi de faire varier l’amplitude de vibration pour une même fréquence de vibration.

Associated with a motor and a heating resistor, it thus becomes possible to:

• heat the shock absorber before or during vibration. A shock absorber does not have the same oscillatory behavior according to its temperature. When cold, the oscillations are less ample than when hot. As a result, when cold, in production we see either a deliberate increase in the duration of vibration to the detriment of productivity, or the appearance of defects on the product.
• pre-load the damper. This thus makes it possible to vary the vibration amplitude for the same vibration frequency.

In the example shown in the , the damper 10 comprises an elastic body 2 formed of a one-piece vibration absorber element and an arrangement of two measuring elements 5A, 5B arranged within the discs 3, 4 according to an arrangement similar to that illustrated on the . As before, the measuring elements have a coaxial arrangement with the elastic body 2.

In the example shown in the , the damper 100 comprises an elastic body 2 comprising a first vibration-absorbing element 20 and a second vibration-absorbing element 21, coaxial with each other along the longitudinal axis XX', as well as a measuring element 3 interposed between said first and second vibration absorber elements, 20, 21. The measuring element has an arrangement similar to that of the .

Advantageously, the vibration dampers 1, 10, 100 previously described include means for communicating the data detected by the measuring element(s) to a data acquisition and/or processing unit. They can advantageously comprise a module for storing the data recorded by the measuring element. A quantified alert of a defect observed in relation to reference values of the expected operating cycle can be provided, said reference value constituting a benchmark to which reference is made to quantify and qualify the defect. It is thus possible to be alerted quickly to the status of several components of the equipment.

A comparison of measurements taken with a vibration damper according to the invention on the one hand and sensors fitted to the equipment but not being integrated into the dampers of the equipment (the sensors have been placed according to conventional arrangements and/ or existing sensors around the shock absorbers) on the other hand, has been achieved.

The measurements recorded are shown in graphs (a), (b), (c) of the . Thus the graphs (a) and (b) of the illustrate the measurements taken with respectively a piezoelectric sensor and a resistive sensor placed on the vibrating equipment, in the vicinity of a damping of the equipment while the graph (c) illustrates the measurements taken with a sensor directly integrated in the damper . These graphs indicate on the abscissa the time and on the ordinate the gross electrical measurement in millivolts per Volt. For the purpose of carrying out the measurements, only the vibrations along the axis XX' were recorded continuously and voluntarily introduced an abnormal increase in the vibration amplitude.

As shown in graph (a), only a variation in the densification of the signals is observed at the time of the increase in amplitude (two increases in amplitude were applied according to a given time interval, these increases of amplitude being indicated by the vertical arrows). The piezoelectric sensor, despite the filters applied, measures too much noise and the signal is too rich to be able to interpret the data in real time. The increase in amplitude is not easily visible. Spectral analysis by FFT (Fast Fourrier Transformation) is all the more complicated as there are many spurious frequencies and the interpretation cannot be automated.

Graph (b) shows that following the increase in amplitude, the measurement is deviated and does not return to its initial oscillation (oscillation before the voluntary increase in amplitude) so that sensor recalibration is required.

With resistive or capacitive sensors according to a conventional assembly, the problem lies in their sensitivity to shocks and strong accelerations. The space required for a shock-resistant sensor is greater than the diameter of the shock absorber and in most cases imposes a height that is not compatible with the operation of the vibration tool. In the event of shocks, exceeding the capacity of the sensor, the latter goes into safety and no longer produces a signal. In the case where even the sensor is well sized in relation to the shocks, a sudden change in the oscillation can alter the resistive gauges (or the capacitive sensors).

The graph (c) obtained with the smart damper according to the invention, on the other hand, shows a distinct and instantaneous measurement in response to the increase in amplitude, which then returns to its initial oscillation. The damper according to the invention thus makes it possible to obtain only the data necessary for permanent monitoring while having relevant visibility as soon as an anomaly appears.

The experiments carried out therefore show that assemblies with sensors (piezoelectric, resistive and capacitive) arranged around the shock absorbers present several problems such as (i) resistance to accelerations and an aggressive environment in terms of dust and humidity, ( ii) the quality, reliability, relevance and accuracy of the data collected, (iii) the ease and adaptability when integrating such a measurement system into an existing vibration device, and finally (iv) calibration of the measuring system. The measurements taken with conventional devices have two major drawbacks: either the data is very rich and difficult to interpret and analyze in real time (graph (a)); or the alert is not given because the sensors saturate following a malfunction (graph (b)). On the contrary, integrated into the component parts of the shock absorber, the measuring element makes it possible to acquire only the data necessary for permanent monitoring while having relevant visibility as soon as an anomaly appears (graph (c)).

The invention is described in the foregoing by way of example. It is understood that the person skilled in the art is able to carry out different variant embodiments of the invention without departing from the scope of the invention.

Claims (13)

Vibration damper (1, 10, 100) allowing continuous monitoring of the operation of vibrating equipment with which it is associated, said damper comprising a body (2) made of elastic material with a longitudinal axis (XX') interposed between two discs ( 3, 4) rigid, characterized in that it comprises within it at least one measuring element (5, 5A, 5B) of the frequency of vibration, of the amplitude and/or of the acceleration of movement and of the force exerted on the damper by the vibrating equipment when the latter is equipped with said damper, said measuring element (5, 5A, 5B) being arranged in the damper and mechanically coupled to the elastic body (2). Vibration damper (1, 10, 100) according to Claim 1, characterized in that the measuring element (5, 5A, 5B) has a coaxial arrangement with the elastic body (2). Vibration damper (1, 10, 100) according to Claim 1 or Claim 2, characterized in that the measuring element (5, 5A, 5B) is arranged at one of the ends of the body (2) elastic. Vibration damper (10) according to any one of Claims 1 to 3, characterized in that it comprises two measuring elements (5A, 5B) arranged respectively on either side of the ends of the elastic body (2). Vibration damper (10) according to any one of Claims 1 to 3, characterized in that at least one of the measuring elements is encapsulated in one of the discs (3, 4). Vibration damper (100) according to Claim 1 or Claim 2, characterized in that the elastic body (2) comprises a first vibration-absorbing element (20) and a second vibration-absorbing element (21) aligned along the axis longitudinal (XX'), the measuring element (5) being interposed between said first and second vibration absorber elements (20, 21). Vibration damper (1, 10, 100) according to Claim 1 or Claim 2, characterized in that the elastic body (2) delimits within it a cylindrical receiving chamber in which the measuring element is accommodated. Vibration damper (1, 10, 100) according to one of the preceding claims, characterized in that the measuring element is a force sensor. Vibration damper (1, 10, 100) according to any one of the preceding claims, characterized in that it includes means for communicating the data detected by the measuring element to an acquisition and/or processing unit of data. Vibration damper (1, 10, 100) according to any one of the preceding claims, characterized in that it comprises a module for storing the data detected by the measuring element. Vibration damper (1, 10, 100) according to any one of the preceding claims, characterized in that it includes means for heating the elastic body (2). Vibration damper (1, 10, 100) according to any one of the preceding claims, characterized in that the discs (3, 4) are connected together by a motorized screw in order to pre-tension the damper. Vibrating equipment for the production of concrete products equipped with at least one vibration damper (1, 10, 100) according to any one of the preceding claims.