Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/06—Investigating concentration of particle suspensions
  • G01N15/0656—Investigating concentration of particle suspensions using electric, e.g. electrostatic methods or magnetic methods
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
  • G01F1/662—Constructional details
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/74—Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/704—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter
  • G01F1/708—Measuring the time taken to traverse a fixed distance

Definitions

• Microwave measuring arrangement for determining the loading of a two-phase ⁇ flow
• the invention relates to a microwave measuring arrangement for determining the Bela ⁇ tion of a two-phase flow with gaseous carrier medium in a Rohroder channel system with small and smallest solids and / or diesstechnikssparti ⁇ angles.
• a preferred field of application of the invention is the determination of the loading of a gas stream with solid particles in large-volume pneumatic solid transport systems, for example the loading of a stream of air with ground coal in a pipe or duct system of a coal power plant.
• microwaves of a predetermined frequency or a predetermined frequency range are coupled into an electrically conductive section of the pipe or channel system prepared as a measuring section, and at the end of the measuring section a change of parameters of the microwaves, for example the frequency, is evaluated .
• the frequency of the waveguide fundamental wave or a frequency range around the waveguide fundamental wave is preferably used in order to avoid unnecessarily complicating the evaluation or to minimize interference.
• the predetermined frequency or the predetermined frequency range of the coupled-in microwave is thus dependent on the geometric dimensions of the measuring path.
• the physical background of the measurement principle is the fact that the Dielektri ⁇ optoelectronic sensor works of the laden with solid particles gaseous carrier medium is dependent upon the amount of performed in a gaseous carrier medium solid particles and microwaves in dependence of the dielectric constant of the medium in which they propagate, a change of its parameters , eg their resonance frequency, their amplitude, their phase.
• DE 44 26280 A1 describes a method for determining the loading of a gas stream with solids fractions, in particular for controlling the firing of a boiler with coal dust in a coal power plant, in which the measurement of the absorption of electromagnetic waves along a measuring gas line carrying the laden gas stream the solid content is closed in the gas stream.
• DE 33 17 215 A1 discloses a method for the quantitative determination of sample particles, in which the sample particles are brought into the electromagnetic field generated by a microwave generator, wherein at least the change of a parameter of the electromagnetic field is measured and from the measured change to the amount of Sample particles is closed.
• the solutions described above have found little input into practice due to a high susceptibility coupled with a low accuracy of measurement.
• the reason for the high susceptibility to interference and low measurement accuracy is in interference, the reflected light from the pipe or channel system, resulting in the measured distance ⁇ penetrating microwaves.
• the coupled-in microwaves in the pipe or channel system such as in a waveguide, are conducted over long distances and reflected and / or diffracted at constrictions, branches, bends or ends. It comes to the superposition of back and forth running waves and thus hardly analyzable measurement signals or significant falsification of the measurement results.
• EP 0 669 522 A2 describes a device and a method for measuring a powder mass flow in a powder-gas mixture, in which a microwave resonator is attached from outside to a delivery line or surrounds it as a cavity resonator. In the case of the attached from the outside to the delivery line cavity resonator, the measurement is carried out only in a partial flow of the powder-gas mixture. If, usually encountered as in large-volume feeding lines occur over the cross section of the conveyor ⁇ line different particle loadings of the powder-gas mixture has to be partly also expected strands increased particle concentration, can only in a Tei.lstrom of the powder-gas mixture carried out measurements are severely faulty.
• measuring electrodes are arranged, by means of which different cutoff frequencies and different frequency ranges of microwaves coupled can be evaluated by measurement entspre ⁇ accordingly of the decreasing diameter of the pipe sections.
• the pipe sections are held by electrically conductive rods that radiate from the outer wall of each pipe section to the inner wall of the transport pipe. This is intended to prevent the coupled ⁇ micro waves can pass through the space between the inner wall of the transport tube and the outer wall of the pipe sections.
• the described measuring ⁇ arrangement is characterized by a relatively large measuring range. The disadvantage is that the installation of pipe sections in the transport pipeline is complicated and the flow conditions within the transport pipeline are significantly affected.
• DE 101 64 107 C1 discloses a microwave measuring device for determining the loading of a two-phase flow with gaseous carrier medium with small and very small solid and / or liquid particles, in which in an existing electrically conductive material portion of the pipe or channel system in the longitudinal direction , before and after the measuring path, in a known manner from a transmitting antenna for coupling microwaves in the pipe or channel system and a receiving antenna for receiving in their parameters, such as resonance frequency, amplitude and / or phase, along the measuring ⁇ distance changed microwaves is formed, depending on an electrically conductive rod, field ⁇ bar called, is introduced so that the limited by the field members section of the pipe or channel system in conjunction with the field rods for the coupled microwaves acts as a resonator.
• the distance between the field bars and thus the section of the pipe or channel system bounded by the field bars determines the resonant frequency of the resonator. It is chosen so that it corresponds to the wavelength of the waveguide fundamental wave of the electrically conductive material best ⁇ existing section of the pipe or duct system.
• the field bars are approximately in the plane of polarization of the coupled microwaves and within the respective cross-sectional area of the electrically conductive portion of the pipe or channel system lying radially at least to the center of the cross-sectional area protruding disposed. Due to the arrangement of the field Rods is to be effected that outside the measuring section in the pipe or Kanalsys ⁇ tem by reflection, diffraction and / or superimposed changed microwaves, which can cause falsifications of the measurement results, short-circuited and thus do not penetrate into the measuring section.
• the microwave measuring device are at a distance of approximately one eighth of the wavelength of the resonance frequency of the resonator ⁇ catalyst which is formed by the field rods and the confined by the field rods portion of the pipe or duct system, outside of the resonator in parallel with the field bars in the direction of the field bars or oppositely directed auxiliary field bars arranged.
• the arrangement of the auxiliary field rods is intended to counteract a falsification of the measurement results by microwaves whose reflection in the pipe or channel system by reflection, diffraction and / or superimposition in their polarization plane and / or phase position whose electric field strength at the location of the field bars is zero, by outside these microwaves short circuit the resonator and thus prevent their penetration into the test section.
• the distance of the field bars should be chosen so that it is about twice the wavelength of the waveguide fundamental wave of the existing electrically conductive material portion of Pipe or
• a microwave measuring arrangement for determining the loading of a two-phase flow with gaseous carrier medium in a tube or channel system with small and very small solid and / or liquid particles has a transmitting antenna and a receiving antenna which are arranged in the longitudinal direction of a straight electrically conductive section of the tube which carries the two-phase flow. or channel system with a constant cross-sectional geometry spaced from each other and thus form a measuring path in a known manner.
• About the transmitting antenna linearly polarized microwaves are coupled.
• the microwave measuring arrangement furthermore has two electrically conductive bars, referred to below as field bars, which in the longitudinal direction of the straight electrically conductive section of the tube or channel system with constant cross-sectional geometry, before and after the measuring section aligned therewith, within a respective cross-sectional area of the straight electrically conductive Section of Rohroder channel system, with constant cross-sectional geometry, extending into the interior of the straight electrically conductive portion of the pipe or channel system, projecting with constant cross-sectional geometry, are arranged so that the field bars and the straight electrically conductive portion of the pipe or
• Channel system with constant cross-sectional geometry between the field rods act as a resonator for the coupled via the transmitting antenna linearly polarized microwaves.
• Characteristic of the invention is that assigned to each field bar in the cross-sectional area of the straight electrically conductive portion of the pipe or channel system in which extends the field bar, or in a compared to
• these auxiliary field bars are electrically conductively connected to the straight electrically conductive portion of the pipe or channel system and radially from the inner wall of the straight electrically conductive portion of the pipe ⁇ or channel system, projecting at least to the center of the cross-sectional area, and in the longitudinal direction of the straight electrically conductive portion of the pipe or channel system aligned with each other.
• the Field bars preferably in the straight electrically conductive portion of the pipe or duct system with constant cross-sectional geometry electrically connected to the straight electrically conductive portion of the pipe or duct system.
• the field bars are further aligned approximately in the plane of polarization of the coupled linearly polarized micro ⁇ waves and in the longitudinal direction of the straight electrically conductive portion of the pipe or channel system to the transmitting and receiving antenna and radially from the inner wall of the straight electrically conductive portion of the pipe or Channel system, at least to the center of the cross-sectional area projecting trained.
• the distance of the field rods is at least in each case one-tenth to transmit or receive antenna, especially before ⁇ Trains t each case at least half the wavelength of the waveguide fundamental wave of straight electrically conductive portion of the pipe or sewer system with equal ⁇ constant cross-sectional geometry.
• the straight electrically conductive section of the pipe or channel system which has a constant cross-sectional geometry acting in conjunction with the field bars, to have a circular cross-section.
• the cross-sectional area of the delivery line section may as well be oval, square, rectangular or polygonal.
• the center of the cross-sectional area is to be understood as the respective geometric center.
• Below the mean diameter the average distance between two opposite wall surface elements of the straight electrically conductive section of the pipe or channel system with consistent cross-sectional geometry are understood.
• the uniqueness of the measurement results and the achievable accuracy of measurement microwaves of a frequency range between 0.95 to 1, 5 times the frequency of the waveguide fundamental wave should be coupled.
• the frequency of the waveguide fundamental wave to determine the loading of a two-phase flow with the inventive microwave measuring arrangement should be between transmitting and receiving antenna located measuring path length between 0.8 to 3 times, preferably 1, 5 times, the average diameter of the straight electrically conductive portion of the pipe or channel system with constant Querterrorismsgeome ⁇ trie.
• the field bars are then in the longitudinal direction of the straight electrically conductive ⁇ capable section of the pipe or channel system with an approximately the
• the electrical system formed from field bars and straight electrically conductive portion of the pipe or channel system with constant cross-sectional geometry then acts as a resonator for microwaves with the frequency of the waveguide fundamental wave.
• the field rods causing short-circuited on the one via the transmitting antennas coupled microwaves or at least considerably attenuated, and thus do not or hardly propagate in the pipe or channel system and on the other into the pipe or sewer system interspersed micro ⁇ waves and / or microwaves altered by reflection, diffraction and superposition outside the measuring section, which can cause falsifications of the measurement results, be short-circuited or at least significantly attenuated and thus can not reach the measuring section.
• the effect of the field bars is not sufficient to achieve sufficiently good measurement results or for a sufficiently large measurement accuracy, because despite the arrangement of the field bars still significantly the measurement result falsifying disturbances in the form of, for example, reflected microwaves
• the particular advantage of the arrangement of the auxiliary field rods according to the invention is that the length of the lenmessan extract required to install a microwave-inventive straight electrically conductive pipe or duct ⁇ section does not increase with a constant cross-sectional geometry that therefore only a straight electrically conductive pipe or channel portion with constant cross-sectional geometry is required with such a length as required for the arrangement of the field bars to form a microwave resonator formed of field bars and the straight electrically conductive portion of the pipe or channel system with constant cross-sectional geometry with the frequency of the waveguide fundamental is. This is for the subsequent installation of the microwave measuring arrangement in an existing pipe or duct system of particular importance.
• auxiliary field bars causes a significant increase in the measurement accuracy of the microwave measurement arrangement.
• the signals received at the receiving antenna with the described measuring arrangement enable a precise evaluation in a known manner by means of frequency measurement, so that a highly accurate determination of a shift of the resonance frequency of the field rods and the straight electrically conductive portion of the pipe or channel system with constant cross-sectional geometry Resonator due to a loading of the flowing in the resonator gaseous carrier medium with small and smallest solid and / or liquid particles is possible.
• the shift of the resonance frequency is then, starting from a calibration measurement with a predetermined loading of the gaseous carrier medium with small and smallest solids and / or liquid particles, a measure of the loading of the gaseous carrier medium with small and smallest solid and / or liquid particles.
• the distance between the two field bars associated auxiliary field rods to the field bar in the longitudinal direction of the straight electrically conductive portion of the pipe or channel system with constant cross-sectional geometry is a maximum of one tenth, preferably a maximum of thirtieth, the wavelength of the waveguide fundamental wave of the straight electrically conductive portion of the pipe or channel system with constant cross-sectional geometry.
• the auxiliary field bars can be arranged in the longitudinal direction of the straight electrically conductive section both in the direction of the measuring path and in the opposite direction spaced from the field bar.
• the auxiliary field bars are preferably designed and arranged such that they span the cross-sectional area of the straight electrically conductive section of the tube or channel system with constant cross-sectional geometry at least half, preferably more than two-thirds, and crossing the center of the cross-sectional area. It is expedient if the length of the auxiliary field bars corresponds to the length of the field bars.
• the particular advantage of the microwave measuring arrangement according to the invention consists in its simple and space-saving design, which makes it possible to integrate the measuring arrangement even with complicated geometry and space in an existing pipe or duct system. In this case, the measurement results obtained with the microwave measuring arrangement according to the invention by means of evaluation of the sensed at the receiving antenna electrical signals in a known manner by means
• microwave measuring device will be explained in more detail using an exemplary embodiment.
• FIG. 1 shows a broken-off electrically conductive section of a pipe or channel system with a microwave measuring arrangement
• FIG. 2 shows a longitudinal section of the electrically conductive section of a pipe or channel system with a microwave measuring arrangement
• FIG. 3 shows a cross section of the electrically conductive portion of a pipe or channel system with a microwave measuring arrangement
• FIG. 4 shows an example of the relationship between the displacement of the Reso ⁇ nanzfrequenz and the loading of the two-phase flow with a coal dust ⁇ .
• Fig. 1 shows a straight electrically conductive portion F of a pipe system 1 for the pneumatic transport of coal dust, as found in pulverized coal combustion plants of coal power plants.
• At least the wall of the section F of the pipe system 1 consists of electrically conductive corrosion-resistant steel.
• the cross-sectional geometry of the section F of the pipe system 1 is equal over the length of the section F. From the outside, projecting into the interior of the section F of the pipe system 1, in the longitudinal direction of the section F of the pipe system 1 in succession at a distance of 375 mm, forming a measuring section S, a transmitting antenna 2 and a receiving antenna 3 are mounted. About the transmitting antenna 2 microwaves are coupled with frequencies between 340 MHz to 352 MHz.
• the frequency of the hollow ⁇ conductor fundamental wave of the conductive portion F of the pipe system 1 is approximately
• the wavelength of the waveguide fundamental wave is therefore approx.
• each field bar 4, 4 ' associated with each 2 auxiliary field bars 6, 7 and 6' 7 'respectively .
• the auxiliary field bars 6, 7 and 6 '7' are arranged in the longitudinal direction of the section F of the Rohrsys ⁇ tems 1 in alignment with each other.
• the system of field rods 4, 4 'and electrically conductive portion F of the pipe system 1 formed by the above-described arrangement of the field rods 4, 4' in the straight electrically conductive portion F of the pipe system 1 acts electrically for linearly polarized microwaves at the frequency of the waveguide fundamental as a resonator.
• Section F of the pipe system 1 coupled linearly polarized microwaves with the frequency of the waveguide fundamental wave by the field bars 4, 4 'shorted ⁇ sen or at least significantly attenuated. This has the effect that the linearly polarized microwaves coupled in via the transmitting antenna 2 do not or hardly propagate outside the section bounded by the field bars 4, 4 'in the pipe system 1.
• the arrangement of the field rods 4, 4 ' is further causes in the pipe system 1 interspersed microwaves with approximately the frequency of the waveguide fundamental and approximately one polarization, according to the coupled via the transmitting antenna 2 microwaves and / or by reflection, diffraction and superposition , Modified outside the section F of the pipe system 1 microwaves with the frequency of the waveguide fundamental wave and approximately one polarization, corresponding to the coupled via the transmitting antenna 3 microwaves, which can cause falsifications of the results are shorted or at least significantly attenuated and thus not or hardly in the
• FIG. 4 shows, for the arrangement described above, the loading of the transport air stream in the pipe system 1 with pulverized coal as a function of the change in the resonance frequency of the pipe rods 4, 4 'and the straight electrically conductive section F of the pipe or channel system 1 with constant cross ⁇ cut geometry formed resonator due to the loading of the transport air ⁇ stream in the resonator with coal dust particles.
• the frequencies of the coupled via the transmitting antenna 2 microwaves are between 340 MHz and
• the loading of the transport air stream with coal dust is inversely proportional to the square of the change in the resonant frequency. In the region of the change in the resonance frequency shown in FIG. 4, this relationship is quasi linear.
• the frequency of the waveguide fundamental wave of this straight electrically conductive portion F of the pipe system 1 is about 439 MHz, which corresponds to a wavelength of 680 mm.
• the distance S between the transmitting and the receiving antenna 2, 3, ie the length of the measuring section S, is 150 mm.
• the Hiltsfeldstäbe 6, 7 and 6 ', 7' are, as shown in Figures 1 to 3, the field bars 4, 4 'assigned.
• the distance G of the auxiliary field bars 6, 7 or 6 ', 7' to the respective Feistäben is 8 mm or 16 mm.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Chemical & Material Sciences (AREA)
• Electromagnetism (AREA)
• Analytical Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Dispersion Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Measuring Volume Flow (AREA)
• Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
• Measurement Of Resistance Or Impedance (AREA)

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• 2016
  • 2016-11-04 DE DE102016013220.5A patent/DE102016013220B3/de not_active Expired - Fee Related
• 2017
  • 2017-10-27 US US16/346,629 patent/US10697813B2/en active Active
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  • 2017-10-27 CN CN201780067822.3A patent/CN109906369B/zh not_active Expired - Fee Related
  • 2017-10-27 AU AU2017353079A patent/AU2017353079B2/en not_active Expired - Fee Related
  • 2017-10-27 KR KR1020197015510A patent/KR20190079647A/ko active IP Right Grant
  • 2017-10-27 EP EP17808750.8A patent/EP3535562A1/de not_active Withdrawn
  • 2017-10-27 JP JP2019544767A patent/JP2020504312A/ja active Pending
  • 2017-10-27 WO PCT/DE2017/000362 patent/WO2018082726A1/de unknown
  • 2017-10-27 CA CA3043429A patent/CA3043429A1/en not_active Abandoned
• 2019
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