CA2546634A1 - Apparatus and method for measuring strip velocity - Google Patents
Apparatus and method for measuring strip velocity Download PDFInfo
- Publication number
- CA2546634A1 CA2546634A1 CA 2546634 CA2546634A CA2546634A1 CA 2546634 A1 CA2546634 A1 CA 2546634A1 CA 2546634 CA2546634 CA 2546634 CA 2546634 A CA2546634 A CA 2546634A CA 2546634 A1 CA2546634 A1 CA 2546634A1
- Authority
- CA
- Canada
- Prior art keywords
- meter
- velocity
- strip
- electromagnetic energy
- transceiver
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- 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
- G01F1/663—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 by measuring Doppler frequency shift
-
- 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
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/86—Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Fluid Mechanics (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
A meter (10) is provided for measuring a velocity of a metallic strip or band (30) moving along a straight path (26). The meter (10) includes an antenna positioned at a location along the path (32)) pointing towards the strip edge at an oblique angle, and a transceiver electrically connected to the antenna. The transceiver transmits, in conjunction with the antenna, a field of electromagnetic energy of known magnitude and frequency and receives reflected electromagnetic energy from material (35) crossing the field to produce a signal related to the magnitude and the Doppler-shifted frequency of the reflected electromagnetic energy. The meter (10) also includes an amplifier coupled to the transceiver, a control unit for calibration, and a central processing unit. The central processing unit generates an output signal (4-20mA current loop or voltage output) based upon data received from the control unit and a signal received from the amplifier, proportional to the measured strip velocity.
Description
APPARATUS AND METHOD FOR MEASURING STRIP VELOCITY
Background and Summary of the Invention The present invention relates to an arrangement for the contactless measurement of the velocity of a moving strip, band or a sheet of material.
More particularly, the present invention relates to an arrangement for the contactless measurement of a velocity of a sheet of material moving through an electromagnetic field of known frequency and and power based upon the frequency shift of the electromagnetic energy backscattered off the edge of the sheet. The innovative part of this invention is the utilization of the backscatter mode of reflection of microwave radiation, off an edge of flat band or a strip of material to facilitate the doppler shift measurement.
Doppler radar could not be applied in its normal configuration, that is obtaining a retrograde reflection off a bulk and smooth sheets of material, because flat surfaces of typical bulk sheet materials like plastics and metals, do not produce any measurable microwave backscatter reflection at an oblique angle (i.e. the retrograde reflections where the reflected beam travels back to the receiver along the same path as the transmitted beam). A measurable microwave reflection off a flat surface takes place only at the reflection angle equal to the incident angle and as such it requires the receiver to be placed away from the transmitter, except when the incidence angle is 90 degrees. In either case the Doppler effect is nullified.
DESCRIPTION
Introduction The present invention addresses the above-described problem associated with the microwave Doppler velocity meters, by utilizing the backscatter reflection off an edge of the material strip, where the electromagnetic beam is directed towards an edge at an oblique angle (not 90 degrees); for example at 45 degree.
The beam could be pointed towards the edge within the plane of the strip, or from a any arbitrary direction, as long as the beam incidence angle to the linear edge is not 90 degrees. Electromagnetic energy impinging upon the sharp edge gets scattered quasi-isotropically to a degree depending on the irregularities in the structure or geometry of the edge. In case of metallic strips the reflection is maximized when the polarity of the electric field is at right angle to the direction of the edge of the strip. The higher the irregularity (i.e. more jagged the edge) the higher the amount of energy is being scattered quasi-isotropically, as compared to the amount of energy that is reflected off the edge in the forward direction as in 45 the normal equal-angle reflection.
A small portion of that quasi-isotropically scattered energy travels back in the direction towards the transceiver.and may get detected, providing that the sensitivity is sufficiently high. Such backscattered energy suffers the same 50 Doppler shift when reflected off the edge of a moving strip as if retro-reflected of a moving target, that is the received beam exhibits a Doppler frequency shift proportional to the axial component of the strip edge velocity, along the direction of the beam. If the strip velocity is V, C is the speed of light, F denotes the transmitter (microwave) frequency then the frequency received is shifted by 55 DeltaF compared to F, and the incidence beam angle with respect to the strip edge is Theta:
DeltaF = 2*F*(V/C)*COS(Theta) As per Fig.1, A meter (10) is provided for measuring a velocity of a metallic or polymer strips or bands (30) moving along a straight path (26). The meter (10) includes an antenna positioned at a location along the path (32) pointing towards 65 the strip edge at an oblique angle, and a transceiver electrically connected to the antenna. The transceiver transmits, in conjunction with the antenna, a field of electromagnetic energy of known magnitude and frequency and receives reflected electromagnetic energy from material (35) crossing the field to produce a signal related to the magnitude and the Doppler-shifted frequency of the 70 reflected electromagnetic energy. The meter (10) also includes an amplifier coupled to the transceiver, a control unit for calibration, and a central processing unit. The central processing unit generates an output signal (4-2OmA current loop or voltage output) based upon data received from the control unit and a signal received from the amplifier, that is proportional to the measured strip velocity.
Explanation of terms:
Antenna - "microwave antenna" device that receives electromagnetic energy from a transmitter and radiates it onto free space, and/or a device that receives electromagnetic energy from space and passes it into receiver. A property of a directional antenna is that the emmitted energy is radiated predominantly in one direction in form of a narrow beam, and that it is sensitive to the received energy only from a certain narrow range of direction. Important property of antennas is that the receiveing and transmitting characteristics are almost always identical.
Background and Summary of the Invention The present invention relates to an arrangement for the contactless measurement of the velocity of a moving strip, band or a sheet of material.
More particularly, the present invention relates to an arrangement for the contactless measurement of a velocity of a sheet of material moving through an electromagnetic field of known frequency and and power based upon the frequency shift of the electromagnetic energy backscattered off the edge of the sheet. The innovative part of this invention is the utilization of the backscatter mode of reflection of microwave radiation, off an edge of flat band or a strip of material to facilitate the doppler shift measurement.
Doppler radar could not be applied in its normal configuration, that is obtaining a retrograde reflection off a bulk and smooth sheets of material, because flat surfaces of typical bulk sheet materials like plastics and metals, do not produce any measurable microwave backscatter reflection at an oblique angle (i.e. the retrograde reflections where the reflected beam travels back to the receiver along the same path as the transmitted beam). A measurable microwave reflection off a flat surface takes place only at the reflection angle equal to the incident angle and as such it requires the receiver to be placed away from the transmitter, except when the incidence angle is 90 degrees. In either case the Doppler effect is nullified.
DESCRIPTION
Introduction The present invention addresses the above-described problem associated with the microwave Doppler velocity meters, by utilizing the backscatter reflection off an edge of the material strip, where the electromagnetic beam is directed towards an edge at an oblique angle (not 90 degrees); for example at 45 degree.
The beam could be pointed towards the edge within the plane of the strip, or from a any arbitrary direction, as long as the beam incidence angle to the linear edge is not 90 degrees. Electromagnetic energy impinging upon the sharp edge gets scattered quasi-isotropically to a degree depending on the irregularities in the structure or geometry of the edge. In case of metallic strips the reflection is maximized when the polarity of the electric field is at right angle to the direction of the edge of the strip. The higher the irregularity (i.e. more jagged the edge) the higher the amount of energy is being scattered quasi-isotropically, as compared to the amount of energy that is reflected off the edge in the forward direction as in 45 the normal equal-angle reflection.
A small portion of that quasi-isotropically scattered energy travels back in the direction towards the transceiver.and may get detected, providing that the sensitivity is sufficiently high. Such backscattered energy suffers the same 50 Doppler shift when reflected off the edge of a moving strip as if retro-reflected of a moving target, that is the received beam exhibits a Doppler frequency shift proportional to the axial component of the strip edge velocity, along the direction of the beam. If the strip velocity is V, C is the speed of light, F denotes the transmitter (microwave) frequency then the frequency received is shifted by 55 DeltaF compared to F, and the incidence beam angle with respect to the strip edge is Theta:
DeltaF = 2*F*(V/C)*COS(Theta) As per Fig.1, A meter (10) is provided for measuring a velocity of a metallic or polymer strips or bands (30) moving along a straight path (26). The meter (10) includes an antenna positioned at a location along the path (32) pointing towards 65 the strip edge at an oblique angle, and a transceiver electrically connected to the antenna. The transceiver transmits, in conjunction with the antenna, a field of electromagnetic energy of known magnitude and frequency and receives reflected electromagnetic energy from material (35) crossing the field to produce a signal related to the magnitude and the Doppler-shifted frequency of the 70 reflected electromagnetic energy. The meter (10) also includes an amplifier coupled to the transceiver, a control unit for calibration, and a central processing unit. The central processing unit generates an output signal (4-2OmA current loop or voltage output) based upon data received from the control unit and a signal received from the amplifier, that is proportional to the measured strip velocity.
Explanation of terms:
Antenna - "microwave antenna" device that receives electromagnetic energy from a transmitter and radiates it onto free space, and/or a device that receives electromagnetic energy from space and passes it into receiver. A property of a directional antenna is that the emmitted energy is radiated predominantly in one direction in form of a narrow beam, and that it is sensitive to the received energy only from a certain narrow range of direction. Important property of antennas is that the receiveing and transmitting characteristics are almost always identical.
Backscatter reflection - scattering of an electromagnetic (or other) beam of 90 energy upon a target, in all directions including also a direction towards the transmitter, in a similar fashion as beam of light scatters off a matte or rough (unpolished) surface. Part of the backscatter radiation forms the retrograde reflection.
95 CW Radar - "Continous Wave" radar, usually the synonym for Doppler Radar Doppler effect - changing (shifting) of the frequency of a beam of wave (electromagnetic or other) reflected off a moving target, or changing (shifting) of wave frequency emitted by a moving 100 tranmitter. The magnitude of the frequency shift is proportional to the velocity and to the cosine of the angle formed between the velocity vector and the beam. Doppler effect of electromagnetic radiation vanishes in case of "Equal angle reflection" (see above) or when the incident angle equals 90 degree.
Doppler Radar - Radar device utilizing Doppler effect principle for measuring velocity of a moving target. Doppler radars use CW (Continuous Wave) transceiver for at least part of the measurement cycle, which extracts the doppler shift by combining (mixing) the 110 transmitted wave with the received wave. The microwave mixer or detector contained in a receiver, naturally outputs the sum frequency (which is discarded) and the difference frequency which is then amplified and measured. The difference frequency is proportional to the velocity of the target.
Detector - "microwave detector" - electronic component sensitive to weak microwave radiation used for converting such radiation into electrical signal.
120 Equal angle reflection - reflection of a beam off a target at an agle equal to the incidence angle, in a similar fashion as a beam of light reflects off a mirror.
Microwaves - an arbitrarily selected portion of the electromagnetic energy 125 spectrum with the wavelength between decimeters and one-tenth of millimeter. Note: some sources may specify slightly different boundaries, the differences in this terminology are of no practical importance.
130 Mixer - non-linear component that mixes two signal producing signals that have frequency equal to the sum and/or to the difference of input signals. In the case of radar devices, mixer produces the low frequency signal of the frequency equal to the difference between the original transmitter frequency and the received Frequency.
135 The received frequency may be shifted due to reflection off a moving target (CW Doppler radars), or due to the radar-target-radar round-trip delay when the transmitter frequency is varied in time.
140 Receiver - "microwave receiver" - a device that receives incomming microwave radiation and converts it into other form of electrical signals , usually of much lower frequency.
145 Retrograde reflection - reflection of the electromagnetic (or other) beam of energy off a target, propagating back towards the emitter (transmitter, tranceiver) along the direction of the original transmitted beam.
150 Transceiver - transmitter combined with a receiver in one integrated unit.
Transmitter - "microwave transmitter" - device that generates and emmits microwave energy.
95 CW Radar - "Continous Wave" radar, usually the synonym for Doppler Radar Doppler effect - changing (shifting) of the frequency of a beam of wave (electromagnetic or other) reflected off a moving target, or changing (shifting) of wave frequency emitted by a moving 100 tranmitter. The magnitude of the frequency shift is proportional to the velocity and to the cosine of the angle formed between the velocity vector and the beam. Doppler effect of electromagnetic radiation vanishes in case of "Equal angle reflection" (see above) or when the incident angle equals 90 degree.
Doppler Radar - Radar device utilizing Doppler effect principle for measuring velocity of a moving target. Doppler radars use CW (Continuous Wave) transceiver for at least part of the measurement cycle, which extracts the doppler shift by combining (mixing) the 110 transmitted wave with the received wave. The microwave mixer or detector contained in a receiver, naturally outputs the sum frequency (which is discarded) and the difference frequency which is then amplified and measured. The difference frequency is proportional to the velocity of the target.
Detector - "microwave detector" - electronic component sensitive to weak microwave radiation used for converting such radiation into electrical signal.
120 Equal angle reflection - reflection of a beam off a target at an agle equal to the incidence angle, in a similar fashion as a beam of light reflects off a mirror.
Microwaves - an arbitrarily selected portion of the electromagnetic energy 125 spectrum with the wavelength between decimeters and one-tenth of millimeter. Note: some sources may specify slightly different boundaries, the differences in this terminology are of no practical importance.
130 Mixer - non-linear component that mixes two signal producing signals that have frequency equal to the sum and/or to the difference of input signals. In the case of radar devices, mixer produces the low frequency signal of the frequency equal to the difference between the original transmitter frequency and the received Frequency.
135 The received frequency may be shifted due to reflection off a moving target (CW Doppler radars), or due to the radar-target-radar round-trip delay when the transmitter frequency is varied in time.
140 Receiver - "microwave receiver" - a device that receives incomming microwave radiation and converts it into other form of electrical signals , usually of much lower frequency.
145 Retrograde reflection - reflection of the electromagnetic (or other) beam of energy off a target, propagating back towards the emitter (transmitter, tranceiver) along the direction of the original transmitted beam.
150 Transceiver - transmitter combined with a receiver in one integrated unit.
Transmitter - "microwave transmitter" - device that generates and emmits microwave energy.
Claims (26)
1. An apparatus for measuring the velocity of a metallic or dielectric strip material moving along a straight path at an assumed velocity, the apparatus comprising:
a source that generates a field of electromagnetic energy through which a material moving along a flow path passes; a receiver that receives an amount of electromagnetic energy reflected from the material which is proportional to the concentration of material moving along the flow path; and means for processing the amount of electromagnetic energy reflected from the material passing through the field and the assumed velocity to generate a signal representing a mass flow rate of the material.
a source that generates a field of electromagnetic energy through which a material moving along a flow path passes; a receiver that receives an amount of electromagnetic energy reflected from the material which is proportional to the concentration of material moving along the flow path; and means for processing the amount of electromagnetic energy reflected from the material passing through the field and the assumed velocity to generate a signal representing a mass flow rate of the material.
2. The apparatus of Claim 1, wherein the response is linear for a range of magnitudes of reflected electromagnetic energies.
3. The apparatus of Claim 1, wherein the response is a voltage proportional to the velocity of the strip material.
4. The apparatus of Claim 1, wherein the field of electromagnetic energy has a frequency in a microwave range.
5. The apparatus of Claim 1, wherein the field of electromagnetic energy is positioned at a fixed location along the edge of the strip material.
6. The apparatus of Claim 1, further comprising means for detecting a change in frequency between the field of electromagnetic energy and the electromagnetic energy reflected from the material passing through the field to generate, in conjunction with the processing means, a response related to the velocity of the material.
7. The apparatus of Claim 6, wherein the response is linear for a range of reflected electromagnetic energies.
8. A meter for measuring a velocity of a strip material moving along a straight path at an assumed velocity.
9. The meter of Claim 8, wherein the transmitted electromagnetic energy has a microwave frequency.
10. The meter of Claim 8, wherein the transmitting and detecting means include an antenna and a transceiver.
11. The meter of Claim 10, wherein an output of the transceiver is electrically connected to the converting means and a signal appears at the output that is related to the velocity of the strip.
12. The meter of Claim 8, wherein the converting means includes means for amplifying the signal appearing at the output of the transceiver.
13. The meter of Claim 12, wherein the amplifying means has an adjustable gain and a generally flat magnitude response for a predetermined frequency range.
14. The meter of Claim 13, wherein the predetermined frequency range is in an audio frequency range.
15. The meter of Claim 8, further comprising control means for configuring and calibrating the converting means to generate the response.
16. A meter for measuring a velocity of a strip moving along a straight path, the meter comprising: an antenna positioned at a location along the flow path; a transceiver electrically connected to the antenna, the transceiver transmitting, in conjunction with the antenna, a field of electromagnetic energy of known magnitude and frequency and receiving reflected electromagnetic energy from the strip edge crossing the field to produce a signed related to the strip velocity;
an amplifier electrically connected to the transceiver and amplifying the signal produced by the transceiver; a control unit enabling calibration for a particular strip velocity; and a central processing unit electrically connected to the amplifier and control unit and generating at least one output signal based upon data received from the control unit and a signal received from the amplifier.
an amplifier electrically connected to the transceiver and amplifying the signal produced by the transceiver; a control unit enabling calibration for a particular strip velocity; and a central processing unit electrically connected to the amplifier and control unit and generating at least one output signal based upon data received from the control unit and a signal received from the amplifier.
17. The meter of Claim 16, wherein the antenna includes a W band 25-32dB gain horn antenna.
18. The meter of Claim 16, wherein the transceiver includes a gunn diode transceiver.
19. The meter of Claim 16, wherein the amplifier has an adjustable gain and a generally flat magnitude response for a predetermined frequency range.
20. The meter of Claim 19, wherein the response is generally flat from 0 to kilo Hertz.
21. The meter of Claim 16, wherein the control unit includes a manual entry interface.
22. The meter of Claim 16, wherein the central processing unit generates a current output related to the measured strip velocity.
23. The method of Claim 16, wherein the transmitted electromagnetic energy has a microwave frequency.
24. The apparatus of claim 1, further comprising means for determining a value for the assumed velocity of the strip moving along the path.
25. The meter of claim 8, further comprising means for determining a value for the assumed velocity of the strip moving along the path.
26. The meter of claim 16, further comprising means for determining a value for the assumed velocity of the strip moving along the path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2546634 CA2546634A1 (en) | 2006-05-15 | 2006-05-15 | Apparatus and method for measuring strip velocity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2546634 CA2546634A1 (en) | 2006-05-15 | 2006-05-15 | Apparatus and method for measuring strip velocity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2546634A1 true CA2546634A1 (en) | 2007-11-15 |
Family
ID=38686886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2546634 Abandoned CA2546634A1 (en) | 2006-05-15 | 2006-05-15 | Apparatus and method for measuring strip velocity |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2546634A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130307563A1 (en) * | 2010-12-21 | 2013-11-21 | Georg Keintzel | Method And Device For Measuring The Speed Of A Rolling Stock |
-
2006
- 2006-05-15 CA CA 2546634 patent/CA2546634A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130307563A1 (en) * | 2010-12-21 | 2013-11-21 | Georg Keintzel | Method And Device For Measuring The Speed Of A Rolling Stock |
| KR101904519B1 (en) * | 2010-12-21 | 2018-10-04 | 프리메탈스 테크놀로지스 오스트리아 게엠베하 | Method and device for measuring the speed of a rolling stock |
| US10228333B2 (en) * | 2010-12-21 | 2019-03-12 | Primetals Technologies Austria GmbH | Method and device for measuring the speed of a rolling stock |
| US10753886B2 (en) | 2010-12-21 | 2020-08-25 | Primetals Technologies Austria GmbH | Method and device for measuring the speed of a rolling stock |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |