WO2007149007A1 - Procédé et dispositif de mesure d'écarts - Google Patents

Procédé et dispositif de mesure d'écarts Download PDF

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Publication number
WO2007149007A1
WO2007149007A1 PCT/RU2006/000550 RU2006000550W WO2007149007A1 WO 2007149007 A1 WO2007149007 A1 WO 2007149007A1 RU 2006000550 W RU2006000550 W RU 2006000550W WO 2007149007 A1 WO2007149007 A1 WO 2007149007A1
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WIPO (PCT)
Prior art keywords
measuring
output
signal
distance
input
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Application number
PCT/RU2006/000550
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English (en)
Russian (ru)
Inventor
Alexander Vladimirovich Maslovsky
Original Assignee
Radar Technologies-2T, Ltd.
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Filing date
Publication date
Application filed by Radar Technologies-2T, Ltd. filed Critical Radar Technologies-2T, Ltd.
Publication of WO2007149007A1 publication Critical patent/WO2007149007A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons

Definitions

  • the invention relates to measuring technique and can be used to measure gaps between parts of machines and mechanisms, in particular, to control the distance between the upper ends of the rotor blades and the inner surface of the rotor machine body.
  • Measurement of the true value of radial clearances during operation and the use of measurement results to control radial clearances during testing and regular operation of rotary machines can significantly improve their technical and economic parameters and reliability.
  • SUBSTITUTE SHEET (RULE 26) grind when interacting with the blades, do not allow to measure radial clearances when they increase.
  • the disadvantage of these methods is the inability to provide the required measurement accuracy at high temperatures, for example, at 1200 0 C, in the measured gap region even if cooling is applied to the elements installed in the gas-air path of the rotary machine.
  • ⁇ 4 ⁇ l / ⁇ , (1) where / is the measured distance, ⁇ is the oscillation wavelength.
  • the measurement of the phase difference is usually carried out using a phase detector having a periodic dependence of the output signal on the phase difference of the signals at its inputs (see. Radar Reference. Edited by M. Skolnik. New York, 1970: Translated from English. (in four volumes) / Under the general editorship of K.N. Trofimov; Volume 3. Radar devices and systems / Under the editorship of A.S. Vinitsky. - M .: Sov Radio, 1978, 528 s, ill., p. . 183 [8]), for example:
  • U 0 is the voltage amplitude of the phase detector.
  • the total phase difference is determined as
  • a ⁇ ⁇ 1 + 2 ⁇ , (3)
  • phase method provides high accuracy in measuring distances, but it does not allow us to unambiguously determine the unknown value of "n" (which for most real-world applications is tens or hundreds of thousands) for calculating the total phase difference. This feature leads to the fact that the phase method is used either in complex multi-frequency systems, or in combination with other methods, or to measure a distance, the change of which is guaranteed to not exceed half the wavelength of the oscillation.
  • the distance measuring system comprises a generator with a frequency controlled by voltage, the subharmonic signal of which from the output of the frequency divider is transmitted by the emitter to the side of the measured object and in the rough measurement mode is fed to the reference input of the phase comparison device, mainly a phase detector, to the second input of which a signal reflected from the object.
  • the output voltage of the phase comparison tool which is the criterion for setting a certain value of the phase difference of the emitted and received signals, is fed through the filter to the generator frequency control input.
  • the system is a circuit for automatically adjusting the frequency (AFC) of the generator to the discriminator frequency, which is determined by the propagation time of the signal to the object and vice versa.
  • a mode is provided in which the harmonic of the transmitted signal, i.e., the signal of the generator, is supplied to the reference input of the phase detector.
  • the value of the steady-state frequency is determined by the frequency meter, and the computing device connected to it calculates the distance and displays the result on the display.
  • SUBSTITUTE SHEET allow you to determine the distance from one value of the phase difference of the emitted and received signals at the same frequency.
  • the main disadvantage of the method and system is the possibility of unstable operation when measuring rapidly variable distances.
  • Closest to the proposed invention is based on the use of the phase method of measuring distance, a device for measuring radial clearances between the ends of the blades and the casing surrounding them (see German patent N ° 19705769 [H]) using a microwave radar.
  • the radar system includes a transmitting and receiving device, from which the microwaves through the waveguide are directed in the main radial or axial direction to the impeller.
  • the waveguide aperture is located at a very small distance above the edges of the blades, which allows you to very accurately determine whether the blade edge is directly opposite the aperture. In this case, the microwaves are reflected, and from the reflected signal you can determine the distance from the blades to the waveguide and, therefore, to the wall of the casing.
  • the installation of a number of such waveguides at the boundary of the volume captured by the blades allows one to determine the radial or axial clearance in various parts of the casing.
  • the disadvantage of this solution, as well as other known solutions, is the dependence of the radial clearance measurements on the temperature and vibration parameters of the waveguide, which transmits electromagnetic waves from the radar transceiver to the antenna and vice versa.
  • the peculiarity of measuring the radial clearances of rotary machines is that it requires measurements in a wide temperature range from minus 60 degrees Celsius to plus 1200 degrees Celsius when exposed to measuring equipment
  • phase systems the phase is actually measured due to the passage of the electromagnetic wave from the oscillation generator 1 through the connecting 4 and directional 2 elements, the signal transmission line 5, the antenna 6, the propagation medium 9 (i.e., the space between the antenna combined with the inner surface and the surface 8 to which the gap is measured) to the reflecting surface 7 and back through the propagation medium, antenna, signal line, connecting and auxiliary elements to the phase detector 3 (Fig. 1), on the second the course of which reference signal is supplied, as a rule, flowing from the generator.
  • the generator, connecting and directional elements together form a phase measurement system 10.
  • the change in the phase shift during the measurements can be due to both a change in the radial clearance value and a change in the length of the path of the measuring system along which electromagnetic waves pass.
  • the path traveled by the signal through the phase measuring system (CIF) is, firstly, small, since the elements are concentrated in a limited volume, and secondly, stable, since the temperature of the CIF cannot vary over a wide range, and it, usually cooled or thermostated.
  • the body of the rotary machine can be significantly heated during operation, and the installation site of the antenna system is surrounded by various elements, therefore, for better cooling of the CIF and simplification of installation, it is advisable to relate the electronic
  • SUBSTITUTE SHEET (RULE 26) equipment at a certain distance from the antenna installation site, using a waveguide or coaxial communication line for signal transmission.
  • the transmission line which in the general case may contain various bends, is exposed to temperatures and vibrations, which leads to a change in its length and shape (Fig. 2).
  • the measured radial clearance 11, as a rule, does not exceed fractions of wavelengths, and the length of the communication line 5 (L) can be tens to hundreds of wavelengths, so even a slight relative change in the length of the communication line can lead to a significant absolute change in its length and, therefore, to the occurrence of a measurement error of the actual clearance.
  • SUBSTITUTE SHEET (RULE 26) increase 12 of the measured value 9 of the radial clearance relative to the actual 11 5 and if using CIF (see point U in Fig. 2) - to decrease 13. Fixing the measuring system at two points leads to an additional change in the shape of the communication line due to the influence of temperature and relative moving attachment points.
  • a change in the shape of the communication line caused by both temperature and vibration leads to a change in the coefficient of the standing wave and, consequently, to a change in the ratio between the signal level reflected from the surface to which the distance is measured and the signal reflected by the communication line R, which changes the phase of the signal, arriving at the input of the phase detector, and leads to the occurrence of a measurement error ⁇ L (f).
  • the problem to which the present invention is directed is to increase the accuracy of measuring distances between elements of machines and mechanisms, including the radial clearance between the ends of rotor blades and the rotor machine body during its operation and when the elements of the measuring equipment are exposed to temperature and vibration .
  • the technical result is achieved due to the fact that to measure the gaps between the parts of machines and mechanisms using irradiation with electromagnetic waves of an object to which
  • SUBSTITUTE SHEET (RULE 26) o + 2 ⁇ ) / 4 ⁇ , where ⁇ is the wavelength of oscillations, Aq) 1 is the phase shift between the signals of the reference and measuring channels obtained during measurements, A ⁇ 0 is the phase shift between the signals of the reference and measuring channels obtained during the calibration of the measuring system at zero range to the reflecting object.
  • L ypcu is the length of the measuring path of the device for receiving the measuring signal 10, containing the oscillation generator, connecting, directional and other auxiliary elements
  • L 011 is the length of the measuring path of the communication line 5, including antenna 6, at normal pace temperature and unchanged shape
  • ALJt - change in the length of the transmission line of the signals of the measuring channel due to the difference in temperature from the normal one
  • ALJf - change in the length of the transmission line of signals of the measuring channel due to the change in its shape
  • SUBSTITUTE SHEET (RULE 26) changing the length of the path traveled by electromagnetic waves through both channels due to the influence of temperature or changing the shape of the signal transmission line will be the same, and the signal at the output of the phase comparison device (for example, a phase detector) will depend only on the phase difference of the measuring and reference channels,
  • the signals received through these channels in the absence of a radial clearance i.e., when the radial clearance is zero, will have a phase shift (A ⁇ 0 ) equal to zero. If the length of the reference and measuring channels is somewhat different, then the phase shift between the signals received through these channels at a zero radial clearance will have a non-zero value, which must be taken into account when determining the true value of the radial clearance (d) using the expression
  • a device that implements the proposed method contains a common oscillator 1 for the measuring and reference channels, directional elements 2 and 18, for example, circulators, measuring and reference channels, signal transmission line 5 and measuring channel antenna 6, signal transmission line 16 and a reflector 17 of the reference channel, as well as a phase detector 3, i.e., a device for comparing the phases of the signals received from the measuring and reference channels, and a computer 19, which determines the distance to the object using the measured phase difference.
  • SUBSTITUTE SHEET (RULE 26)
  • the signal from the output of the generator 1 is fed to the inputs And directed elements 2 and 18 of the measuring and reference channels, respectively.
  • the input B of the directional element 2 is connected to one end of the transmission line 5 of the measuring channel, the second end of which is connected to the antenna 6, which emits electromagnetic waves in the direction of the reflecting object 7, to which the distance is measured, and receiving reflected oscillations from it, which are transmitted through the signal transmission line arrive at the input B of the directional element 2 and from its output C to one input of the phase detector 3.
  • the signal from the output C of the directional element 18 of the reference channel is received at the second input of the phase detector 3, after the signal from the generator 1 passes through the input A of the directional element 18 to the input B of this element at one end of the reference channel signal transmission line 16, at the second end of which there is a reflector 17 reflecting electromagnetic waves, which are transmitted to the reference channel signal transmission line 16 input ⁇ of the directional element 18, from the output of which then they are fed to the second input of the phase detector 3.
  • the inventive method of measuring gaps between parts of machines and mechanisms is implemented using the inventive device containing an electromagnetic oscillation generator, a directional element connected to it, one of the inputs of which is connected to one side of the signal transmission line connected to the antenna on the other side, and the output the directional element is connected to one of the inputs of the phase detector, the other input of which is connected to the oscillation generator, and the output is connected to a computer that determines the distance to the reflect its object according to the known wavelength of the oscillations and the measured value of the phase shift between the reflected signal and the signal of the generator, while improving the accuracy of distance measurements when exposed to the elements of the device temperature and vibration is ensured by additionally introduced elements of the reference channel, identical to the elements forming the measuring channel of the generator oscillations connected to the input of the directional element, the second input of which is connected to one end of the signal transmission line, is structurally identical and mechanically combined with the signal line of the measuring channel, at the second end of which a fixed reflecting element is placed next to the emitter of the measuring channel
  • SUBSTITUTE SHEET (RULE 26) in proportion to the sine of the distance to the reflecting object.
  • amplification and normalization of the signal from the output of the phase detector requires the use of analog DC amplifiers that have low time and temperature stability, which reduces the accuracy of the measurements.
  • phase detectors which have higher parameters and can be implemented using digital signal processing.
  • the signals from the output of the directional elements, for example, the circulators of the reference and measuring channels, are fed to the inputs of the mixers, which form the signals of the difference frequencies, which then enter the input of the low-frequency phase detector.
  • FIG. 5 A block diagram of a device operating in accordance with the above description is shown in FIG. 5.
  • the signal from the output of the generator 1 is fed to the inputs A of the circulators of the measuring 2 and reference 18 channels, as well as to the synchronization input of the generator 20.
  • the signal From the output B of the circulator 2, the signal enters the signal transmission line 5 of the measuring channel and is emitted by the antenna 6 in the direction of the reflecting object 7 the distance to which is measured.
  • the signal reflected by the object 7 is received by the antenna and transmitted through the signal transmission line to the input B of the circulator 2, from the output of which then goes to one of the inputs of the mixer 22.
  • SUBSTITUTE SHEET (RULE 26) mixer 22 receives a signal from the generator 20, synchronized in phase with the signal of the generator 1 and different from it in frequency by 10 ... 1,000,000 kHz. From the output of the mixer, a signal with a frequency of 10 ... 1,000,000 kHz and a phase determined by the path length traveled by the signal through the measuring channel is fed to the input of the low-frequency phase detector 23. At the second input of the detector 23, from the output of the mixer 21, a signal with a frequency of 10 ... 1,000,000 kHz with phase determined by the length of the path traveled by the signal along the reference channel.
  • the signal at the output of the mixer is formed by converting in the mixer 21 the signals supplied to it from the output of the generator 20 and the output C of the reference channel circulator 18.
  • a signal is formed after the signal passes from the generator 1 to the input A of the circulator 18, from the output B of the circulator 18 to the input of the signal transmission line of the reference channel 16 and along the transmission line to the reflector 17 and back through line 16 to the circulator input B.
  • SUBSTITUTE SHEET obtained by measuring and reference channels during the calibration process at a distance to the reflecting object equal to zero.
  • FIG. 6 A block diagram of a channel switching apparatus is shown in FIG. 6.
  • the signal from the output of the generator 1 is fed to the input of the generator 20 for synchronization, as well as to the input A of the circulator 2, the output of which is fed to the input of the switch 24, alternately switching with a high frequency F P > 2 ⁇ F, determined by the signal from block 25 control switches, this signal is either on the transmission line of the signals of the measuring channel, or on the transmission line of the signals of the reference channel.
  • the signal transmitted through the communication line, reflected from the reflector 17, if the reference channel is connected, or from the reflecting object 7, if the measuring channel is connected, is fed through the switch 24 to the input B of the circulator 2, from the output of which it is then fed to one of the inputs of the mixer 26.
  • the second input of the mixer 26 receives a signal from the generator 20, which is synchronized in phase with the generator 1 and detuned from it by the frequency ⁇ F.
  • a signal with a frequency ⁇ F is supplied to the input of the switch 27, which synchronously with the switch 24 s, the frequency determined by block 25 switches the signal either to the input of the reference channel signal recovery circuit 28 or to the input of the measuring channel signal recovery circuit 29, the outputs of which reconstructed signals with a frequency ⁇ F arrive at
  • SUBSTITUTE SHEET (RULE 26) the input of the phase detector 23, forming a signal proportional to the phase difference due to the different path lengths traveled by the signal through the reference and measuring channels.
  • phase incursions that occur during the passage of the signal through elements 1, 2, 24, 20, 26, 27 are the same when processing the reference and measuring signals, errors associated with a change in the linear dimensions and distances between these elements of this device due to the influence of temperature and other factors are not affect the accuracy of determining the distance to the reflecting object.
  • the signal from the output of the phase detector 23 is fed to the input of the calculator 19, which determines the distance to the object.
  • the frequency of the signal coming from the output of the phase detector ⁇ F is lower than the switching frequency of the switches ⁇ F P and satisfies the condition F P > 2 ⁇ F, and its value is in the range of 20 ... 2000000 kHz, for which various firms produce a wide range of analog-to-digital converters ( ATTTT). Therefore, instead of signal recovery circuits 28 and 29, an ADC can be used, and further signal processing, including phase detection, can be carried out in digital form. In this case, the digital device can perform both phase detection and calculation of the distance to the object.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

La présente invention concerne un procédé permettant de mesurer des écarts séparant des pièces de machines et de mécanismes, qui consiste à irradier, à l'aide d'oscillations électromagnétiques, un objet situé à une distance que l'on mesure. Le procédé selon l'invention est caractérisé en ce qu'il fait appel à deux canaux, à savoir un canal de mesure et un canal de référence, et est mis en oeuvre par l'intermédiaire d'un dispositif comprenant des éléments supplémentaires, qui sont identiques aux éléments du canal de mesure et forment un canal de référence, un générateur d'oscillations, et un élément directionnel relié à la sortie dudit générateur d'oscillations. L'une des entrées dudit élément directionnel est reliée à une extrémité de la ligne de transmission de signaux, qui est structurellement identique et mécaniquement couplée à la ligne de transmission de signaux du canal de mesure. La seconde extrémité de ladite ligne de transmission de signaux comporte, à côté d'un élément rayonnant d'antenne du canal de mesure, un contacteur se présentant sous la forme d'un élément réfléchissant fixe. La sortie de l'élément directionnel est reliée à l'une des entrées d'un détecteur de phase, dont la seconde entrée est reliée à la sortie de l'élément directionnel du canal de mesure, et dont la sortie est reliée à un calculateur déterminant la distance séparant de l'objet réfléchissant.
PCT/RU2006/000550 2006-06-15 2006-11-16 Procédé et dispositif de mesure d'écarts WO2007149007A1 (fr)

Applications Claiming Priority (2)

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RU2006120753 2006-06-15
RU2006120753/28A RU2307999C1 (ru) 2006-06-15 2006-06-15 Способ и устройство для измерения зазоров (варианты)

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WO2007149007A1 true WO2007149007A1 (fr) 2007-12-27

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Publication number Priority date Publication date Assignee Title
RU2457432C1 (ru) * 2010-12-30 2012-07-27 Учреждение Российской академии наук Институт проблем управления сложными системами РАН (ИПУСС РАН) Способ измерения радиальных зазоров и осевых смещений торцов лопаток рабочего колеса турбины

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SU1237904A1 (ru) * 1982-09-27 1986-06-15 Вильнюсский Филиал Экспериментального Научно-Исследовательского Института Металлорежущих Станков Способ измерени зазора между растрами фотоэлектрических растровых преобразователей перемещений
EP0603863A1 (fr) * 1992-12-25 1994-06-29 Nec Corporation Méthode et instrument pour mesurer l'écartement de cellule d'un membre biréfringent
US5739524A (en) * 1994-07-13 1998-04-14 European Gas Turbines Sa Dynamic distance and position sensor and method of measuring the distance and the position of a surface using a sensor of this kind
RU2115886C1 (ru) * 1996-06-11 1998-07-20 Московский государственный институт электроники и математики Способ измерения зазора до металлической поверхности и устройство для его осуществления
RU2156435C1 (ru) * 1999-08-03 2000-09-20 Московский государственный технологический университет "СТАНКИН" Бесконтактный датчик перемещений
RU2237866C2 (ru) * 2001-11-16 2004-10-10 Дженерал Электрик Компани Способ и устройство для измерения зазора до вершин лопаток турбины

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU1237904A1 (ru) * 1982-09-27 1986-06-15 Вильнюсский Филиал Экспериментального Научно-Исследовательского Института Металлорежущих Станков Способ измерени зазора между растрами фотоэлектрических растровых преобразователей перемещений
EP0603863A1 (fr) * 1992-12-25 1994-06-29 Nec Corporation Méthode et instrument pour mesurer l'écartement de cellule d'un membre biréfringent
US5739524A (en) * 1994-07-13 1998-04-14 European Gas Turbines Sa Dynamic distance and position sensor and method of measuring the distance and the position of a surface using a sensor of this kind
RU2115886C1 (ru) * 1996-06-11 1998-07-20 Московский государственный институт электроники и математики Способ измерения зазора до металлической поверхности и устройство для его осуществления
RU2156435C1 (ru) * 1999-08-03 2000-09-20 Московский государственный технологический университет "СТАНКИН" Бесконтактный датчик перемещений
RU2237866C2 (ru) * 2001-11-16 2004-10-10 Дженерал Электрик Компани Способ и устройство для измерения зазора до вершин лопаток турбины

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