CA2569839A1 - Method for correcting the influence of signal transmission lines on changes of signal transit times when conducting ultrasonic measurements - Google Patents
Method for correcting the influence of signal transmission lines on changes of signal transit times when conducting ultrasonic measurements Download PDFInfo
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- CA2569839A1 CA2569839A1 CA002569839A CA2569839A CA2569839A1 CA 2569839 A1 CA2569839 A1 CA 2569839A1 CA 002569839 A CA002569839 A CA 002569839A CA 2569839 A CA2569839 A CA 2569839A CA 2569839 A1 CA2569839 A1 CA 2569839A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
- G01L5/246—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed using acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/02—Analysing fluids
- G01N29/032—Analysing fluids by measuring attenuation of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/30—Arrangements for calibrating or comparing, e.g. with standard objects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
- G01N29/341—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/46—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by spectral analysis, e.g. Fourier analysis or wavelet analysis
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/01—Indexing codes associated with the measuring variable
- G01N2291/011—Velocity or travel time
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02827—Elastic parameters, strength or force
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/04—Wave modes and trajectories
- G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/10—Number of transducers
- G01N2291/101—Number of transducers one transducer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/269—Various geometry objects
- G01N2291/2691—Bolts, screws, heads
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- Chemical & Material Sciences (AREA)
- Immunology (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Pathology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Mathematical Physics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
The invention relates to a method and device for correcting the influence of signal transmission lines (15) and electronic measuring units (9) on changes of transit times (t) of ultrasonic pulses (7), particularly when conducting pretension measurements or tension measurements on a connecting part (1) by using ultrasonic waves. In order to determine parasitic transit time portions, which are caused by the electronic measuring unit (9) and/or the signal transmission line (15), the transit time of an electrical signal reflected by an end of the signal transmission line (15), this end being remotely located from the measuring unit, is recorded. This is used for correcting observed ultrasonic transit times through the connecting part (1). The connecting part (1) is connected to the end of the signal transmission line (15), said end being remotely located from the measuring unit, via an ultrasonic transducer (5).
Description
LITERAL
Method for correcting the influeflce of signal transmission lines on changes in the signal propagation time during ultrasound measurements 'Y'echri,ical field The stressing force of connecting components, for example the prestressing force of screws or bolts, can be determined using an ultrasound measurement method, for which purpose an ultrasound measuring device is generally connected to an ultrasound transducer, which is fitted to the connecting component, by means of a signal transmission line. The ultrasound waves are injected into the connecting component to be checked using pulsed excitation, for example. After the ultrasound signal has been injected into the component to be checked, the signal propagation time of particular ultrasound pulse echoes of the ultrasound pulse which has previously been injected into the connecting component is measured. The change in the signal propagation time is used to determine the prestressing force.
Prior art in methods which are already used nowadays, a pulse generator, for example a programmable arbitrary function generator, which has a power amplifier section is generally used to generate digitally controllable signals, A transient recorder including a power amplifier is generally used to detect signals. The additional components of such an ultrasound measuring syste.m are a computer which, in addition to control, is also used for data acquisition and evaluation and is provided with appropriate software.
Method for correcting the influeflce of signal transmission lines on changes in the signal propagation time during ultrasound measurements 'Y'echri,ical field The stressing force of connecting components, for example the prestressing force of screws or bolts, can be determined using an ultrasound measurement method, for which purpose an ultrasound measuring device is generally connected to an ultrasound transducer, which is fitted to the connecting component, by means of a signal transmission line. The ultrasound waves are injected into the connecting component to be checked using pulsed excitation, for example. After the ultrasound signal has been injected into the component to be checked, the signal propagation time of particular ultrasound pulse echoes of the ultrasound pulse which has previously been injected into the connecting component is measured. The change in the signal propagation time is used to determine the prestressing force.
Prior art in methods which are already used nowadays, a pulse generator, for example a programmable arbitrary function generator, which has a power amplifier section is generally used to generate digitally controllable signals, A transient recorder including a power amplifier is generally used to detect signals. The additional components of such an ultrasound measuring syste.m are a computer which, in addition to control, is also used for data acquisition and evaluation and is provided with appropriate software.
DE 42 25 035 Al and DE 42 32 254 Al disclose an ultrasound testing method. According to this method, a frequency-modulated chirp signal x(t) whose izastantaneous frequency f is zlot modulated linearly with time t is provided for the purpose of driving an ultrasound transducer which is arranged in a transmission path. The temporal profile f(t) of the instantaneous frequency f of the frequency-modulated chirp signal x(t) in the transfer function H(f) is matched to the prescribed transmission path. The temporal change in the instantaneous frequency f of the frequency-modulated chirp signal x(t) is correlat.ed with that value of the transfer function H(f) of the transmission path which is assooiated with this frequency f in such a manner that, at frequencies f with a low associated value of the transfer function H(f), the speed of the frequency change is slower than at frequencies f with a high associated value of the transfer function H(f). A square-wave chirp signal, xl(t) is used to drive the ultrasound transducer. A
device which is intended for ultrasound testing and has a signal generator for driving an ultrasound trazxsducer with a frequency-modulated chirp signal x(t) whose instantaneous frequen,cy f does not linearly depend on time, as well as a pulse compression filter for converting the chirp signal y(t), which is received by the latter or by another ultrasound transducer, into a short received pulse z(t) are also proposed.
The disadvantage of the known methods is the fact that changes in the obsexved propagation time of the ultrasound pulse echo may be caused not only by the change in the propagation time of the ultrasound signal to be observed but also by changes in the propagation time in the signal transmission lines and in the electronic ultrasound measuring device. rn addition to the known influences of moisture and temperature, these changes may also be caused by the measuring cable being replaced or by the electronic maasuxing device or parts of the latter being replaced, for instance as a result of design-dictated differences.
The changes in the propagation time of the ultrasound pulse echo caused thereby result in errors when determining the propagation time of the ultrasound pulse echo if they are not taken into account. This is disadvantageous, in particular, when slight changes, as may occur, for exaTnple, as a result of the slow setting of a screw coTmection, are intended to be reliably observed or when a screw connection or bolt connection is intended to be rechecked after some time.
Summary of the it'1ZrEntion zn, order to determine the prestressir.g force of connecting components, for example screws, the ultrasound propagation time of an ultrasound sigrial in the unscrewed state of the screw is measured and is then stored in a computer. This is used as a reference value. The difference irx, the propagation time of an ultrasound pulse which was transmitted by a screw in the screwed state is used to determine the prestressing force. The difference in the propagation times of the two uZtrasound signals is used to calculate the prestressing force of the screw, Physically speaking, orily the ultrasound propagation tims of one ultrasouzid signal is measured in the screw. From the metrological point of view, it is necessary to take into account the signal propagation time inside a signal transmission line and/or an adapter which is connected to the latter as well as the signal propagation time inside an electronic measuring device. Tf the latter are not corrected or taken into account, the lengths of signal transmission lines which can be used as well as the choice of tightening tool or adapter and the component tolerances are restricted.
device which is intended for ultrasound testing and has a signal generator for driving an ultrasound trazxsducer with a frequency-modulated chirp signal x(t) whose instantaneous frequen,cy f does not linearly depend on time, as well as a pulse compression filter for converting the chirp signal y(t), which is received by the latter or by another ultrasound transducer, into a short received pulse z(t) are also proposed.
The disadvantage of the known methods is the fact that changes in the obsexved propagation time of the ultrasound pulse echo may be caused not only by the change in the propagation time of the ultrasound signal to be observed but also by changes in the propagation time in the signal transmission lines and in the electronic ultrasound measuring device. rn addition to the known influences of moisture and temperature, these changes may also be caused by the measuring cable being replaced or by the electronic maasuxing device or parts of the latter being replaced, for instance as a result of design-dictated differences.
The changes in the propagation time of the ultrasound pulse echo caused thereby result in errors when determining the propagation time of the ultrasound pulse echo if they are not taken into account. This is disadvantageous, in particular, when slight changes, as may occur, for exaTnple, as a result of the slow setting of a screw coTmection, are intended to be reliably observed or when a screw connection or bolt connection is intended to be rechecked after some time.
Summary of the it'1ZrEntion zn, order to determine the prestressir.g force of connecting components, for example screws, the ultrasound propagation time of an ultrasound sigrial in the unscrewed state of the screw is measured and is then stored in a computer. This is used as a reference value. The difference irx, the propagation time of an ultrasound pulse which was transmitted by a screw in the screwed state is used to determine the prestressing force. The difference in the propagation times of the two uZtrasound signals is used to calculate the prestressing force of the screw, Physically speaking, orily the ultrasound propagation tims of one ultrasouzid signal is measured in the screw. From the metrological point of view, it is necessary to take into account the signal propagation time inside a signal transmission line and/or an adapter which is connected to the latter as well as the signal propagation time inside an electronic measuring device. Tf the latter are not corrected or taken into account, the lengths of signal transmission lines which can be used as well as the choice of tightening tool or adapter and the component tolerances are restricted.
The method proposed according to the invention allows the measurement technology to be integrated in the end cQxisumer so that the latter can operate with different cable lengths and adapters without any logista.cal outlay for compensating for the measurement techriology used. The method proposed according to the invention can be used to directly measure the actual ultrasound propagation tinies of ultrasound signals in a connecting component, which is in the form of a screw, without interfering influences falsifying the measurement result.
Following the method which is proposed according to the invention and is intended to correct the influence of signal transmissioxl lines on changes in the propagation times of ultrasound sign.aZs, for instance for the purpose of measuring stressing forces in conn,ecting components such as screws or bolts, the reflection of an electrical excitation signal at the remote end of the cable which starts from the electronic measuring device (at the connection location for an ultrasound transducer) is used to determine the propagation time of the cable, which is present, at the time at which the stressing force is measured, and the propagation times in the electronic measuring device. An electrical signal is then partially or completely reflected at one end of a signal transmission line, if appropriate with reversal of the mathematical sign, if the impedance of the component that is connected to said cable end differs from the impedance of the cable. The impedance of the component that is connected to the cable end is also understood as meaning the impedance at the cable end if no compon,ent is corzn,ected there and it is therefore an open cable end. With regard to coaxial cables, the impedance of the cable per se is typically in the range between 50 ohms and 75 ohms. By virtue of the time-resolved detection of the reflected electrical signal (for example pulse), which may be effected using a transient recorder, for example, the propagation time of the electrical signal, which is reflected at the above-defined cable ezad, in the signal transmission line and/or in the electroxzic measuring device is determined, with respect to the zero point of the time base which is synchronized with puJ.se generation (for example is triggered in synchron-ism with excitation), is used during the time-resolved measurement and is also correspondingly used to observe the ultrasound signals, including a possible deviation of the zero point of the time base used from the time of the excitation signal. By virtue of the fact that the appropriate signal is detected, which may be effected electronically, for example, and by virtue of the fact that the propagation time of the sa.gnal that is reflected at the cable end is determined, the instantaneous propagatioaa time up to the transducer, which can be directly connected at this location or slightly upstream or downstream of the latter, is determined. This location is the end of the signal.
transmission line with an adapter. The ultrasound signal is transmitted in, the adapter using a measuring pin which is placed onto the transducer. However, when determining the propagation time of the electrical signal, the measuring pin must not have any contact with the transducer which is generally applied to the top side of the screw to be measured or a similar connectxng component. The propagation time of the electrical signal can be d termizied in the simplest manner, for example, when a measuring piri does not have any contact with the ultrasound transducer when the measurement location is changed. In the case of the usual considerable mismatch of the transducer, the measurement can also be carried out using the electronic signal which has been partially reflected at the contact holder on account of the mismatch. The propagation time determined from the cable reflection comprises both the influence of the electronic measuring device and the influence of the signal transmission line, for example a coaxial cable, per se.
Following the method which is proposed according to the invention and is intended to correct the influence of signal transmissioxl lines on changes in the propagation times of ultrasound sign.aZs, for instance for the purpose of measuring stressing forces in conn,ecting components such as screws or bolts, the reflection of an electrical excitation signal at the remote end of the cable which starts from the electronic measuring device (at the connection location for an ultrasound transducer) is used to determine the propagation time of the cable, which is present, at the time at which the stressing force is measured, and the propagation times in the electronic measuring device. An electrical signal is then partially or completely reflected at one end of a signal transmission line, if appropriate with reversal of the mathematical sign, if the impedance of the component that is connected to said cable end differs from the impedance of the cable. The impedance of the component that is connected to the cable end is also understood as meaning the impedance at the cable end if no compon,ent is corzn,ected there and it is therefore an open cable end. With regard to coaxial cables, the impedance of the cable per se is typically in the range between 50 ohms and 75 ohms. By virtue of the time-resolved detection of the reflected electrical signal (for example pulse), which may be effected using a transient recorder, for example, the propagation time of the electrical signal, which is reflected at the above-defined cable ezad, in the signal transmission line and/or in the electroxzic measuring device is determined, with respect to the zero point of the time base which is synchronized with puJ.se generation (for example is triggered in synchron-ism with excitation), is used during the time-resolved measurement and is also correspondingly used to observe the ultrasound signals, including a possible deviation of the zero point of the time base used from the time of the excitation signal. By virtue of the fact that the appropriate signal is detected, which may be effected electronically, for example, and by virtue of the fact that the propagation time of the sa.gnal that is reflected at the cable end is determined, the instantaneous propagatioaa time up to the transducer, which can be directly connected at this location or slightly upstream or downstream of the latter, is determined. This location is the end of the signal.
transmission line with an adapter. The ultrasound signal is transmitted in, the adapter using a measuring pin which is placed onto the transducer. However, when determining the propagation time of the electrical signal, the measuring pin must not have any contact with the transducer which is generally applied to the top side of the screw to be measured or a similar connectxng component. The propagation time of the electrical signal can be d termizied in the simplest manner, for example, when a measuring piri does not have any contact with the ultrasound transducer when the measurement location is changed. In the case of the usual considerable mismatch of the transducer, the measurement can also be carried out using the electronic signal which has been partially reflected at the contact holder on account of the mismatch. The propagation time determined from the cable reflection comprises both the influence of the electronic measuring device and the influence of the signal transmission line, for example a coaxial cable, per se.
The signal propagation time determined comprises both propagation times - both the influence of the electronic ultrasound measuring device and that of the cable - in the form of a sum. When determining the propagation time of the ultzasound pulse echo, the propagation time of the cable reflection is subtracted from the propagation time of said ultrasound pulse echo so that it is possible to determine the propagatioxi time of the ultrasound pulse echo on, its own without interfering influencing variables which stem from fluctuating or changed device and cable propagation times. in addition, deviations of the zero point of the time base used during the measurement from the time of the excitation signal (for example based on its beginning) are corrected by means of the subtraction.
So that the ultrasound pulse signal (excitation, signal) and the ultrasound pulse echo (detection signal) are not superimposed during detection inside the electronic ultrasound measuring device during the measurement, either a circulator or a commercially available reflectometer can be used. Altexziatively, a signal transmission line of at least sufficient length can be used depending on the frequency range of the ultrasound signal used. For a short ultrasound pulse having a mid-frequexacy of approximately 1 MHz, this would be at least the propagation time corresponding approximately to the pulse width (1 ps) and thus, since the reflection is being measuxed, a cable having a transit time in one dYrectiozi of 0.5 ~zs. The length of the signal tranamission line can be regarded as being sufficient exactly when the propagation path for a pass in the signal transmission line (that is to say in the connecting cable from the electronic measuring device to the ultrasound transducer) correaponds to exactly half the duration of the excitation signal since the signal transmission line is passed through twice in the case of ineasuremes.ts with reflection.
So that the ultrasound pulse signal (excitation, signal) and the ultrasound pulse echo (detection signal) are not superimposed during detection inside the electronic ultrasound measuring device during the measurement, either a circulator or a commercially available reflectometer can be used. Altexziatively, a signal transmission line of at least sufficient length can be used depending on the frequency range of the ultrasound signal used. For a short ultrasound pulse having a mid-frequexacy of approximately 1 MHz, this would be at least the propagation time corresponding approximately to the pulse width (1 ps) and thus, since the reflection is being measuxed, a cable having a transit time in one dYrectiozi of 0.5 ~zs. The length of the signal tranamission line can be regarded as being sufficient exactly when the propagation path for a pass in the signal transmission line (that is to say in the connecting cable from the electronic measuring device to the ultrasound transducer) correaponds to exactly half the duration of the excitation signal since the signal transmission line is passed through twice in the case of ineasuremes.ts with reflection.
Drawing The method proposed according to the invention will be described in more detail below with reference to the drawirxg.
The single figure shows an apparatus for carrying out the method which is proposed according to the invention and is intended to correct the influence of signal transmission lines on the determination of changes in the propagation time when ultrasound signals are in,aected into a connecting component, for example a screw.
Variant embodiments The illustration according to figure I diagrammatically reveals the components of an ultrasound measuring system for detectin,g the signal propagation time of an ult.rasound pulse through a connecting component which is in the form of a screw.
An ultrasound measurement method for measuring the prestressing force of a connecting component which is in the form of a screw will be described below. The prestressing force of the screw is understood as meaning the force with which the screw connects connecting components to one another.
In the illustration, according to figure 1, a connecting component is in the form of a screw. The connecting component 1 comprises a screw head 2 and a shaft 3. A
threaded part 4 which is screwed into a complemeatary thread of a component or can be screwed to a threaded nut extends beneath the shaft 3.
An ultrasound transducer 5(aJ.so referred to aa transducer) for an ultrasound pulse 7 which is to be injected into the conmecting component 1 is situated - $ , above the screw head 2. The ultrasound pulse 7 which is injected into the connecting component I at the ultrasound transducer 5 runs along a propagation path 6 through the connecting component 7, and emerges again from the connecting component, 1, in the form of an electrical ultrasound pulse eclio B, at the ultrasound transducer 5 for the ultrasound pulse 7. t is used to denote the time which elapses between the entry of the ultrasound pulse 7 into the corinecting component 1 and the emergence of the ultrasound pulse echo 8 from the connecting component 1, that is to say the propagation time ot the ultrasound signal.
Tn order to inject the ultrasound pulse 7 into, and to output the electrical ultrasound pulse echo 8 from, the coan,ecting component 1, a signal transmission line 15 which may be in the form of a coaxial cable and has an impedance which is inherent in the signal transmission line 15 extends batweeri the ultrasound transducer 5 and an ultrasound measuring device 9. The ultrasound measuring device 9 is connected to a computer 14 which may be a PC, for example. The ultrasound measuring device 9 is also connected to a pulse generator 10 (arbitrary function generator) which may have a first power amplifier 11. The pulse generator 10 having the first power amplifier 11 generates the ultrasound pulses 7 with the a.nterposition of an ultrasound transducer 5. A transient recorder 12 which may comprise a power amplifier 13 is used by the ultrasoura,d transducer 5 to detect azl electrical ultrasound pulse echo 8 which is output from the connecting componen,t 1.
For the sake of completeness, it shall be mentioned that software which can be used for data acquisition and data evaluation and to control the repetition rate of the ultrasound signals, for example, is implemented in the computer 14 which may be a PC.
In order to determine the propagation time of the signal transmission line 15, which is present at the time at which the stressing force is being measured, and the propagation times of the ultrasound signals through the electronic measuring device 9, use is made of the reflection of an electrical excitation signal at the end (in the case of the ultrasound transducer 5) of the signal transmission line 15. Said signal is partially or completely reflected at one cable end, if appropriate with reversal of the mathematical sign, whenever the impedance of the component (for example ultrasound transducer 5) that is connected to the cable end of the signal transmission line 15 differs from the impedance of the signal transmission line 15 per se. It shall once again be pointed out that the impedance of the component that is connected to the cable end of the signal transmission line 15 is also understood as meaning an open cable end, that is to say the absence of a connected component. ay virtue of the fact that the electrical signal is detected and the propagation time of the signal that is reflected at the end of the signal transmission line 15 is determined, the propagation time up to an ultrasound transducer 5, which can be directly connected at, this location (without a considerable further propagation time) or can be connected slightly upstream or downstream of the latter, is determined.
The propagation time determined from the reflection of the electrical signal inside the signal transmission line 15 comprises both the influence of the electronic ultrasound measuring device 9 on the propagation time and the influence of the signal transmission line 15 on the propagation time of the electrical signal. When determining the signal propagation time of the electrical ultrasound pulse echo 8, the propagation time of the reflection of the electrical signal inside the signal transmission line 15 is subtracted from the propagation time corresponding to said ultrasound pulse echo so that the propagation time of the ultrasound signal through the corznecting component 1 is present on its own without any interfering influence by fluctuating or changed propagation times of the electrical signals in the ultrasound measurirlg device 9 arxd/or in the signal transmission line 15.
In order to prevent the ultrasound pulse 7 (excitation signal) and the ultrasound pulse echo 8 (detection signal) being superimposed during detection in the electronic ultrasourk,d measuring de-vice, use may be made of a circulator or a commercially available reflectometer or an electronically or electrically actuable switch, the electronic switch being abl8 to be in the ~orm of a semiconductor compon.ent, in particular.
Alternatively, a sigrxal transmission line 15 of at least sufficiently suitable length can be used deperiding on the frequency range used. When pulsed excitation is used, an at least sufficient length of the signal transmission line 15 is given when twice the sirzgle propagation time, that is to say the _ propagation time for the signal to be passed and returned in the signal transmission line 15, corresponds to the pulse duration since, in this case, it is not possible for the pulsed excitation to temporally overlap the signal between the reflection at the cable end or at the connector and the ultrasound transducer S. So that the excitat.a,on signal and the detection signal are not superimposed during detection in the electronic ultrasound measuring device 9 during the measurement, u.se may be made either of a circulator which is known per se or of a reflectometer which is known per se.
Alternatively, a signal transmission line 15 of at least sufficiently suitable length and with a transit time of 0.5 ps - in one direction - can be used depending on the frequency range of the ultrasound signal used. In this case, an ultxasound pulse around a - ~.l -mid-frequency of 1 MHz and a pxopagation time corresponding approximately to the pulse width (1. ps) are assumed, for example. Since reflection is used for measurement, a signal transmission line 15 with a sizigl.e transit time of 0.5 s can be used. Tt goes without saying that other transit times in the signal transmission line 15 occur in the case of mid-frequencies other than 1 MHz, The use of a signal transmission line 15 has proved to be more advantageous than a circulator or a reflectometer since it is more inexpensive and advantageously contrasts with the circulator or reflectometer in terms of its functionality.
The propagation time or the phase of the electrical signal or of the ultrasound signal in the signal transmission line 15 on its own or with a connected electronic ultrasound measurirzg device 9 can also be determined in a frequency-dependent manx~er. So that the excitation signal and the detection signal are not superimposed during detection in the electronic ultrasound measuring device 9 duxing the measurement, use may be made either of a circulator which is known per se or of a reflectometer which is known per se. In this case too, a signal transmission line 15 of at least sufficiently suitable length can be used depending on the frequency range used. If a short pulse around a mid-fxequency of 1. MHz is assumed, at least the propagation time corresponding approximately to the pulse width (approximately 1lis) and consequently, since reflection is used for measurement, a cable having a single transit time, that is to say the passage of the electrical signal, in one direction, of approximately 0.5 }is would result. A signal transmission line 15 which is generally more advantageous than a circulator or a reflectometer is preferably used.
In addition, the propagation tinte or the phase and the attenuation of the signal transmission line 1,5 on its own or with an elect.ronic ultrasound measuring device 9 connected to it can also be determined in atrequency-dependent manner. In order to determine the attenuation and the phase response when transmitting signals, recourse is generally had to methods which are based on Fourier transformation FFT or Fourier analysis. To this end, an interval of the transmitted signal or of the signal response, in which the response signal to excitation is situated in the case of pulsed excitation, is digitized, Fast Fvurier transformation (FFT) methods are used to digitally analyze the signal or the signal, response in a spectral manner according to frequencies, the frequency dependence of the amplitude and phase being represented as the result.
This result can also be used further as digital information and may constitute the basa.s for further evaluations.
It is also important that the Fourier transform of a Dirac function (delta pulse) represents a spectrum which has an amplitude that remains the same over all frequencies (also referred to as a white spectxum").
The Dirac function is an infinitesimally short pulse having an area that has been standardized to 111 . If the Dirac function is positioned at the temporal location "0", the phases of all spectral components for representing the frequency components as cosine functions are zero.
Conversely, a response in the form of a Dirac function temporally results for a spectrum with an amplitude which remains the same and a phase of 0, the pulse being temporally positioned at 0. Tf only restricted bandwidths are used, a widened pulse results in the place of the Dirac function, the width of said pulse typically being given by the inverse of the baza,dwidth.
A typical pulse width of 1 second thus results for a - ~.3 -bandwidth of Z,Hz, a pulse width of 1 ms results for a bandwidth of 1 kHz, and a pulse width of 1ps correspondingly results for a bandwidth of I MHz etc.
List of reterence symbols 1 Connecting component 2 Screw head 3 Shaft 4 Threaded part Ultrasound transducer 6 Sourzd path 7 Ultrasound pulse t Propagation time of the ultrasound signal betweerz injection into, and output from, the connecting compoi~ient 8 Ultrasound pulse echo 9 Electronic ultrasound measuring device Pulse generator (arbitrary signal generator) 11 Power amplifier 12 Transient xecorder 13 Preamplifier 14 Computer Signal transmission line
The single figure shows an apparatus for carrying out the method which is proposed according to the invention and is intended to correct the influence of signal transmission lines on the determination of changes in the propagation time when ultrasound signals are in,aected into a connecting component, for example a screw.
Variant embodiments The illustration according to figure I diagrammatically reveals the components of an ultrasound measuring system for detectin,g the signal propagation time of an ult.rasound pulse through a connecting component which is in the form of a screw.
An ultrasound measurement method for measuring the prestressing force of a connecting component which is in the form of a screw will be described below. The prestressing force of the screw is understood as meaning the force with which the screw connects connecting components to one another.
In the illustration, according to figure 1, a connecting component is in the form of a screw. The connecting component 1 comprises a screw head 2 and a shaft 3. A
threaded part 4 which is screwed into a complemeatary thread of a component or can be screwed to a threaded nut extends beneath the shaft 3.
An ultrasound transducer 5(aJ.so referred to aa transducer) for an ultrasound pulse 7 which is to be injected into the conmecting component 1 is situated - $ , above the screw head 2. The ultrasound pulse 7 which is injected into the connecting component I at the ultrasound transducer 5 runs along a propagation path 6 through the connecting component 7, and emerges again from the connecting component, 1, in the form of an electrical ultrasound pulse eclio B, at the ultrasound transducer 5 for the ultrasound pulse 7. t is used to denote the time which elapses between the entry of the ultrasound pulse 7 into the corinecting component 1 and the emergence of the ultrasound pulse echo 8 from the connecting component 1, that is to say the propagation time ot the ultrasound signal.
Tn order to inject the ultrasound pulse 7 into, and to output the electrical ultrasound pulse echo 8 from, the coan,ecting component 1, a signal transmission line 15 which may be in the form of a coaxial cable and has an impedance which is inherent in the signal transmission line 15 extends batweeri the ultrasound transducer 5 and an ultrasound measuring device 9. The ultrasound measuring device 9 is connected to a computer 14 which may be a PC, for example. The ultrasound measuring device 9 is also connected to a pulse generator 10 (arbitrary function generator) which may have a first power amplifier 11. The pulse generator 10 having the first power amplifier 11 generates the ultrasound pulses 7 with the a.nterposition of an ultrasound transducer 5. A transient recorder 12 which may comprise a power amplifier 13 is used by the ultrasoura,d transducer 5 to detect azl electrical ultrasound pulse echo 8 which is output from the connecting componen,t 1.
For the sake of completeness, it shall be mentioned that software which can be used for data acquisition and data evaluation and to control the repetition rate of the ultrasound signals, for example, is implemented in the computer 14 which may be a PC.
In order to determine the propagation time of the signal transmission line 15, which is present at the time at which the stressing force is being measured, and the propagation times of the ultrasound signals through the electronic measuring device 9, use is made of the reflection of an electrical excitation signal at the end (in the case of the ultrasound transducer 5) of the signal transmission line 15. Said signal is partially or completely reflected at one cable end, if appropriate with reversal of the mathematical sign, whenever the impedance of the component (for example ultrasound transducer 5) that is connected to the cable end of the signal transmission line 15 differs from the impedance of the signal transmission line 15 per se. It shall once again be pointed out that the impedance of the component that is connected to the cable end of the signal transmission line 15 is also understood as meaning an open cable end, that is to say the absence of a connected component. ay virtue of the fact that the electrical signal is detected and the propagation time of the signal that is reflected at the end of the signal transmission line 15 is determined, the propagation time up to an ultrasound transducer 5, which can be directly connected at, this location (without a considerable further propagation time) or can be connected slightly upstream or downstream of the latter, is determined.
The propagation time determined from the reflection of the electrical signal inside the signal transmission line 15 comprises both the influence of the electronic ultrasound measuring device 9 on the propagation time and the influence of the signal transmission line 15 on the propagation time of the electrical signal. When determining the signal propagation time of the electrical ultrasound pulse echo 8, the propagation time of the reflection of the electrical signal inside the signal transmission line 15 is subtracted from the propagation time corresponding to said ultrasound pulse echo so that the propagation time of the ultrasound signal through the corznecting component 1 is present on its own without any interfering influence by fluctuating or changed propagation times of the electrical signals in the ultrasound measurirlg device 9 arxd/or in the signal transmission line 15.
In order to prevent the ultrasound pulse 7 (excitation signal) and the ultrasound pulse echo 8 (detection signal) being superimposed during detection in the electronic ultrasourk,d measuring de-vice, use may be made of a circulator or a commercially available reflectometer or an electronically or electrically actuable switch, the electronic switch being abl8 to be in the ~orm of a semiconductor compon.ent, in particular.
Alternatively, a sigrxal transmission line 15 of at least sufficiently suitable length can be used deperiding on the frequency range used. When pulsed excitation is used, an at least sufficient length of the signal transmission line 15 is given when twice the sirzgle propagation time, that is to say the _ propagation time for the signal to be passed and returned in the signal transmission line 15, corresponds to the pulse duration since, in this case, it is not possible for the pulsed excitation to temporally overlap the signal between the reflection at the cable end or at the connector and the ultrasound transducer S. So that the excitat.a,on signal and the detection signal are not superimposed during detection in the electronic ultrasound measuring device 9 during the measurement, u.se may be made either of a circulator which is known per se or of a reflectometer which is known per se.
Alternatively, a signal transmission line 15 of at least sufficiently suitable length and with a transit time of 0.5 ps - in one direction - can be used depending on the frequency range of the ultrasound signal used. In this case, an ultxasound pulse around a - ~.l -mid-frequency of 1 MHz and a pxopagation time corresponding approximately to the pulse width (1. ps) are assumed, for example. Since reflection is used for measurement, a signal transmission line 15 with a sizigl.e transit time of 0.5 s can be used. Tt goes without saying that other transit times in the signal transmission line 15 occur in the case of mid-frequencies other than 1 MHz, The use of a signal transmission line 15 has proved to be more advantageous than a circulator or a reflectometer since it is more inexpensive and advantageously contrasts with the circulator or reflectometer in terms of its functionality.
The propagation time or the phase of the electrical signal or of the ultrasound signal in the signal transmission line 15 on its own or with a connected electronic ultrasound measurirzg device 9 can also be determined in a frequency-dependent manx~er. So that the excitation signal and the detection signal are not superimposed during detection in the electronic ultrasound measuring device 9 duxing the measurement, use may be made either of a circulator which is known per se or of a reflectometer which is known per se. In this case too, a signal transmission line 15 of at least sufficiently suitable length can be used depending on the frequency range used. If a short pulse around a mid-fxequency of 1. MHz is assumed, at least the propagation time corresponding approximately to the pulse width (approximately 1lis) and consequently, since reflection is used for measurement, a cable having a single transit time, that is to say the passage of the electrical signal, in one direction, of approximately 0.5 }is would result. A signal transmission line 15 which is generally more advantageous than a circulator or a reflectometer is preferably used.
In addition, the propagation tinte or the phase and the attenuation of the signal transmission line 1,5 on its own or with an elect.ronic ultrasound measuring device 9 connected to it can also be determined in atrequency-dependent manner. In order to determine the attenuation and the phase response when transmitting signals, recourse is generally had to methods which are based on Fourier transformation FFT or Fourier analysis. To this end, an interval of the transmitted signal or of the signal response, in which the response signal to excitation is situated in the case of pulsed excitation, is digitized, Fast Fvurier transformation (FFT) methods are used to digitally analyze the signal or the signal, response in a spectral manner according to frequencies, the frequency dependence of the amplitude and phase being represented as the result.
This result can also be used further as digital information and may constitute the basa.s for further evaluations.
It is also important that the Fourier transform of a Dirac function (delta pulse) represents a spectrum which has an amplitude that remains the same over all frequencies (also referred to as a white spectxum").
The Dirac function is an infinitesimally short pulse having an area that has been standardized to 111 . If the Dirac function is positioned at the temporal location "0", the phases of all spectral components for representing the frequency components as cosine functions are zero.
Conversely, a response in the form of a Dirac function temporally results for a spectrum with an amplitude which remains the same and a phase of 0, the pulse being temporally positioned at 0. Tf only restricted bandwidths are used, a widened pulse results in the place of the Dirac function, the width of said pulse typically being given by the inverse of the baza,dwidth.
A typical pulse width of 1 second thus results for a - ~.3 -bandwidth of Z,Hz, a pulse width of 1 ms results for a bandwidth of 1 kHz, and a pulse width of 1ps correspondingly results for a bandwidth of I MHz etc.
List of reterence symbols 1 Connecting component 2 Screw head 3 Shaft 4 Threaded part Ultrasound transducer 6 Sourzd path 7 Ultrasound pulse t Propagation time of the ultrasound signal betweerz injection into, and output from, the connecting compoi~ient 8 Ultrasound pulse echo 9 Electronic ultrasound measuring device Pulse generator (arbitrary signal generator) 11 Power amplifier 12 Transient xecorder 13 Preamplifier 14 Computer Signal transmission line
Claims (10)
1. A method for correcting the influence of signal transmission lines (15) and electronic measuring devices (9) on changes in propagation times t of ultrasound pulses (7) during prestressing force measurements or stressing force measurements on a connecting component (1) using ultrasound waves, in which, in order to determine parasitic propagation time components caused by the electronic measuring device (9) and/or the signal transmission line (15), the propagation time of an electrical signal which is reflected at an end of the signal transmission line (15) which is remote from the measuring device is detected and is used to correct observed ultrasound propagation times through the connecting component (1), the connecting component (1) being connected to that end of the signal transmission line (15) which is remote from the measuring device via an ultrasound transducer (5), characterized in that a difference is formed from the detected propagation time of the electrical signal in the signal transmission line (is) and from the observed propagation time t which, after the electrical signal has been generated, is composed of transit times through electronic components, transit times in the signal transmission line (15), transit times of the sound path (6) after an electrical signal has been converted into an acoustic signal until the acoustic signal is converted back into an electrical signal, return times through the signal transmission line (15) and through the electronic components until digitization in a transient recorder (12 ) .
2. The method as claimed in claim 1, characterized in that the frequency dependence of the signal propagation time measured for reflection from the end of the signal transmission line (15) is determined using the phase responses which are determined using a fast Fourier transformation, and the phase response of the ultrasound signal measured in at least one Fourier transform is corrected by forming a difference, after which it is possible to carry out back-transformation if necessary.
3. The method as claimed in claim 1, characterized in that the frequency dependence of the observed amplitudes of the signal which is reflected from that end of the signal transmission line (15) which is remote from the measuring device is determined using fast Fourier transformation, and frequency-dependent attenuation or amplification of the signal that is reflected from the end of the signal transmission line (15), which is used to correct the frequency dependence of the amplitudes of at least one of the observed ultrasound signals, which have been subjected to Fourier transformation, by means of standardization, is determined with reference to the Fourier transform of the transmission signal which is digitally prescribed, after which back-transformation can be carried out for the respective corrected ultrasound signal.
4. The method as claimed in claims 2 and 3, characterized in that the method steps as claimed in claims 2 and 3 are used together.
5. The method as claimed in one of the preceding claims, characterized in that the size and/or shape of the electrical signal reflected at the end of the signal transmission line (15) is/are used to infer that an ultrasound transducer (5) is connected, and, when an ultrasound transducer (5) is not connected, a propagation time measurement or a frequency-dependent phase measurement and/or a frequency-dependent amplitude measurement of the electrical signals is/are carried out for reflection at that end of the signal transmission line (15) which is remote from the measuring device.
6. The method as claimed in one of the preceding claims, characterized in that a manually or electrically or electronically controlled switch can be connected to that end of the signal transmission line (15) which is remote from the measuring device, said switch being able to be used to decouple the ultrasound transducer (5) and to produce a high-impedance connection (open end) or a low-impedance connection (short-circuited end) or a connection having a defined impedance.
7. The method as claimed in one of claims 1 to 4, characterized in that adjustable impedances are produced at that end of the signal transmission line (15) which is remote from the measuring device using manually, electrically or electronically controllable resistors using electronically controllable integrated semiconductor components.
8. The method as claimed in one or more of the preceding claims, characterized in that, in order to generate a signal in the arbitrary signal generator (10), use is made of a signal comprising two different successive signals or signal components which are interrupted for a sufficiently long period of time in order to avoid signal superimposition, one of which is selected to be weaker and/or shorter in order to determine the propagation times in the signal transmission line (15) and in the electronic measuring device (9) and the other of which is selected to have a larger amplitude and/or to last longer in order to determine the propagation time of the electrical ultrasound pulse echo (8) for the sound path (6) in the signal transmission line (15) and in the electronic measuring device (9).
9. The method as claimed in one or more of the preceding claims, characterized in that, in order to calibrate and/or adjust or correct a timing controller in the electronic measuring device (9) and/or in the transient recorder (12), a defined signal transmission line (15) or a defined propagation time element having a known propagation time is temporarily connected to the end of the signal transmission line (15) manually or by means of electrically or electronically actuable switches or is fitted on or in the electronic measuring device (9) upstream of the signal transmission line (15) or between parts of the signal transmission line (15) in such a manner that it can be switched manually, electrically or electronically.
10. An apparatus for carrying out the method as claimed in one or more of claims 1 to 9, said apparatus having an electronic ultrasound measuring device (9) which is connected to a connecting component (1), which has an ultrasound transducer (5), via a signal transmission line (15), the electronic ultrasound measuring device (9) being assigned a signal generating device and a signal detection device, characterized in that part of the signal transmission line (15) runs between the electronic ultrasound measuring device (9) and the ultrasound transducer (5) in such a manner that it can be replaced or runs between the latter in a permanently installed manner, signals being generated using an arbitrary signal generator (10) and signals being detected using a digitizing transient recorder (12), instead of part of the signal transmission line (15), the electronic ultrasound measuring device (9) containing an analog propagation time element.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102004027919.5 | 2004-06-09 | ||
| DE102004027919A DE102004027919B3 (en) | 2004-06-09 | 2004-06-09 | Method for correcting the influence of signal transmission lines on signal propagation time changes in ultrasonic measurements |
| PCT/EP2005/006038 WO2005121773A1 (en) | 2004-06-09 | 2005-06-06 | Method for correcting the influence of signal transmission lines on changes of signal transit times when conducting ultrasonic measurements |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2569839A1 true CA2569839A1 (en) | 2005-12-22 |
Family
ID=35064969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002569839A Abandoned CA2569839A1 (en) | 2004-06-09 | 2005-06-06 | Method for correcting the influence of signal transmission lines on changes of signal transit times when conducting ultrasonic measurements |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1754051B1 (en) |
| CA (1) | CA2569839A1 (en) |
| DE (1) | DE102004027919B3 (en) |
| DK (1) | DK1754051T3 (en) |
| ES (1) | ES2567577T3 (en) |
| WO (1) | WO2005121773A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10126216B2 (en) | 2011-02-17 | 2018-11-13 | Ventana Medical Systems, Inc. | Method for tissue sample fixation |
| JP5732078B2 (en) | 2010-03-04 | 2015-06-10 | ベンタナ メディカル システムズ， インコーポレイテッド | Processing system for processing specimens using acoustic energy |
| US10539487B2 (en) | 2010-03-04 | 2020-01-21 | Ventana Medical Systems, Inc. | Systems and methods for monitoring tissue sample processing |
| CN112461429B (en) * | 2020-11-10 | 2022-05-27 | 西南交通大学 | Ultrasonic pretightening force measurement method for low-elasticity-modulus material bolt |
| CN115389087A (en) * | 2022-08-30 | 2022-11-25 | 西南交通大学 | Method for measuring bolt pretension force based on different modal echo signals |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4413518A (en) * | 1981-07-20 | 1983-11-08 | Ndt Instruments, Inc. | Apparatus and method for measuring the extension of bolts under stress |
| US5029480A (en) | 1990-02-05 | 1991-07-09 | Sps Technologies, Inc. | Ultrasonic load indicating member |
| US5321632A (en) * | 1991-02-26 | 1994-06-14 | Nippon Telegraph And Telephone Corporation | Method and apparatus for measuring the length of a transmission line in accordance with a reflected waveform |
| US5150620A (en) * | 1991-06-19 | 1992-09-29 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Method of recertifying a loaded bearing member |
| US5237516A (en) * | 1991-06-19 | 1993-08-17 | The United States Of America As Represented By The United States National Aeronautics And Space Administration | Method of recertifying a loaded bearing member using a phase point |
| DE4224035A1 (en) * | 1992-07-21 | 1994-01-27 | Siemens Ag | Ultrasound test method for flaw location - using frequency modulated chirp signal whose instantaneous frequency time characteristic is matched to transfer function of transmission path |
| DE4232254A1 (en) * | 1992-07-21 | 1994-04-07 | Siemens Ag | Ultrasonic testing method for locating material defects - driving ultrasonic transducer with FM chirp signal with instantaneous frequency variation matched to transmission path transfer function |
| DE4231429C1 (en) * | 1992-09-19 | 1994-03-24 | Bosch Gmbh Robert | Method and device for ultrasound-controlled tightening of screws |
| US5636147A (en) * | 1995-03-17 | 1997-06-03 | Vermont Electromagnetics Corp. | Method of providing ultrasound electrical impedance matching circuits |
| DE10004425A1 (en) * | 2000-02-02 | 2002-01-17 | Siemens Ag | Network with subscriber device, esp. field device, enables transmitter, receiver transmission, reception time delays to be taken into account for time synchronisation |
-
2004
- 2004-06-09 DE DE102004027919A patent/DE102004027919B3/en not_active Expired - Fee Related
-
2005
- 2005-06-06 CA CA002569839A patent/CA2569839A1/en not_active Abandoned
- 2005-06-06 WO PCT/EP2005/006038 patent/WO2005121773A1/en active Application Filing
- 2005-06-06 EP EP05756264.7A patent/EP1754051B1/en not_active Not-in-force
- 2005-06-06 ES ES05756264.7T patent/ES2567577T3/en active Active
- 2005-06-06 DK DK05756264.7T patent/DK1754051T3/en active
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005121773A1 (en) | 2005-12-22 |
| ES2567577T3 (en) | 2016-04-25 |
| EP1754051A1 (en) | 2007-02-21 |
| EP1754051B1 (en) | 2016-01-20 |
| DE102004027919B3 (en) | 2006-03-30 |
| DK1754051T3 (en) | 2017-01-23 |
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