GB2123237A - Surface detector - Google Patents
Surface detector Download PDFInfo
- Publication number
- GB2123237A GB2123237A GB08218635A GB8218635A GB2123237A GB 2123237 A GB2123237 A GB 2123237A GB 08218635 A GB08218635 A GB 08218635A GB 8218635 A GB8218635 A GB 8218635A GB 2123237 A GB2123237 A GB 2123237A
- Authority
- GB
- United Kingdom
- Prior art keywords
- probe
- wave guide
- detector
- guide means
- detector according
- 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.)
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Classifications
-
- 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
- G01S13/588—Velocity or trajectory determination systems; Sense-of-movement determination systems deriving the velocity value from the range measurement
-
- 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
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
- G01S7/032—Constructional details for solid-state radar subsystems
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
A surface detector 1 for remotely determining the position of a surface 9 of a mass of material comprises microwave generator means 2, wave guide means 3 arranged to receive at one end thereof microwave energy from the generator means, means 4 at the other end of the wave guide means for launching microwave energy into free space and for receiving reflected microwave energy from the surface whose position is to be determined, probe means 6,7,8, mounted in the wave guide means for detecting the interference pattern set up in the wave guide means by interference between microwaves transmitted along the wave guide means from the generator means and microwaves reflected from the surface whose position is to be determined, and detector circuit means 13 connected to and responsive to signals from the probe means for detecting changes in the interference pattern and hence relative movement between the detector and the surface whose position is to be determined. <IMAGE>
Description
SPECIFICATION
Surface detector
This invention relates to a surface detectors.
It is sometimes difficult to determine the position of the surface of a mass of material. For example, it is difficult to determine the level of the surface of a mass of molten glass or molten metal in a ladle or tundish and hence to determine the volume of that molten mass.
The present invention accordingly seeks to provide a detector suitable for remotely determining the position of a surface of a mass of material, such as molten glass or molten metal.
According to the present invention there is provided a surface detector for remotely determining the position of a surface of a mass of material which comprises microwave generator means, wave guide means arranged to receive at one end thereof microwave energy from the generator means, means at the other end of the wave guide means for launching microwave energy into free space and for receiving reflected microwave energy from the surface whose position is to be determined, probe means mounted in the wave guide means for detecting the interference pattern set up in the wave guide means by interference between microwaves transmitted along the wave guide means from the generator means and microwaves reflected from the surface whose position is to be determined, and detector circuit means connected to and responsive to signals from the probe means for detecting changes in the interference pattern and hence relative movement between the detector and the surface whose position is to be determined.
Microwaves can be approximately classified by their position in the electro-magnetic spectrum as being any radiation of frequency between about 200 MHz and about 100 GHz. For ease of reference there exists a recognised subdividing of this range into smaller bands as shown in Figure 1 of the drawings. Like all electromagnetic waves microwaves can be described as composed of electric and magnetic fields varying in strength sinusoidally with time, their directions of oscillation being at right angles to each other and both being perpendicular to the direction of propagation. A horizontally polarised wave is defined as one in which the plane of the electric field is horizontal and a vertically polarised wave is one in which the plane of the electric field-is vertical.
The microwave generator means may comprise any suitable form of microwave generator, such as a magnetron, but is preferably a so-called "Gunn diode".
The wave guide means preferably comprises a rectangular section metal tube which is tuned to the frequency of the microwave energy produced by the microwave generator means.
The means for launching microwave energy into free space conveniently comprises a horn.
The probe means preferably comprises one or more probe wires whose tip or tips project through, but are insulated from, the wall of the wave guide means into the path of the microwave energy. In one form of detector constructed according to the invention the probe means comprises first and second probe wires, the spacing between the first and second probe wires, the spacing between the first and second probe wires measured along the wave guide means being substantially equal to (n + ) Apsw where n isO or an integer, e.g. 1, and Xpsw is the standing wavelength of the microwave power in the wave guide means. In addition the probe means includes a detector corresponding to the, or to each, probe wire which is adapted to detect and amplify voltages induced in the probe wires by the microwave energy.As an example of such a detector there can be mentioned a crystal detector, e.g. one of the gold-bonded germanium type.
When the probe means comprises first and second probe wires, spaced as aforesaid, the respective detectors develop signals, for example d.c. voltage signals, which are proportional to the microwave power in the wave guide at points which are effectively 180 out of phase with one another, i.e. an odd number of half power standing wave wavelengths apart.
The detector circuit accepts an electrical input or inputs from the probe means and derives therefrom an electrical signal or signals which is or are dependent upon changes in the standing wave pattern due to relative movement between the detector and the said other end of the wave guide means. Usually such relative movement will occur due to movement of the surface whose position is to be determined relative to the wave guide means which is fixed. However, in some cases the detector may be moved whilst the surface from which the microwave energy is reflected and whose position is to be determined relative to the wave guide means remains fixed.
The detector circuit means can, for example, be arranged to amplify and then subtract the output signals from the said first and second probe wires and produce a first derived signal that varies sinusoidally with the relative movement to be measured which can be applied to a counter. In this way the detector can be used to count the number of th rough-to-peak and peak-to-trough transitions of the first derived signal caused by such relative movement and the consequent movement of the standing wave pattern.
It is preferred that the probe means shall include a third probe wire whose spacing from the second probe wire measured along the wave guide means is substantially equal to (n + 1/4) Xpsw where n and Apsw are as defined above. A detector is similarly connected to this third probe wire and its output signal is proportional to the microwave power at a point which is effectively 90" out of phase with the power detected by the second probe wire.
The detector circuit means can, for example, be arranged to add the output signals from the detectors for the first and second probe wires, preferably after amplification thereof, to divide this added signal by a factor of 2, and to subtract the resultant signal from the preferably amplified output signal from the third probe wire to give a second derived signal that is a quadrature component of the first derived signal, i.e. a component signal that is 90" out of phase with the first derived signal.
The first and second derived signals can be used to drive an "up-down" counter, thereby enabling the relative movement between the detector and the surface to be measured by counting up the number of trough-to-peak and peak-to-trough transitions of both the first and second derived signals as the reflecting surface moves away from the detector and by counting down the same as the surface moves back towards the detector. The movement as recorded by the counter can then be used to control the operation of a supply device, e.g. a pump, so as to provide automatic control of the level of a liquid in a tank, for example.
In order that the invention may be clearly understood and readily carried into effect a preferred embodiment thereof will now be described, by way of example only, with reference to Figures 2 to 5 of the accompanying drawings, wherein:- Figure2 is a diagrammatic side view of a surface detector constructed in accordance with the present invention, which incorporates a block diagram of the detector circuit;
Figure 3 is a detail sectional view of the probe arrangement mounted in the wave guide of the detector of Figure 2; Figure 4 is a detail sectional view of one of the cartridge diodes that is connected to each of the probes of
Figure 3; and
Figure 5 is a circuit diagram of the detector circuit of Figure 2.
Referring to Figure 2 of the drawings, the detector 1 comprises a microwave generator 2 in the form of a "Gunn diode" to which is attached a wave guide 3 having a horn 4 at its other end for launching microwaves from the wave guide 3 into free space. Adjacent the microwave generator 2 is an attenuator 5 which can be used to vary the amount of microwave energy passing down the wave guide and, in particular, to stop most of the reflected energy from re-entering the generator. Reference numerals 6,7 and 8 indicate probes mounted in the wave guide 3 for detecting the interference pattern set up in the wave guide 3 between microwaves transmitted therealong from the generator 2 and microwaves reflected from the surface 9 whose position is to be determined.These probes are connected by way of leads 10, 11 and 12 to a detector circuit 13, which is described in more detail below, for detecting changes in the interference pattern caused by relative movement between the detector 1 and the surface 9.
The microwave generator 2 is a so-called "Gunn diode". This is a two terminal solid state device which, when placed in a tuned cavity and connected to a suitable d.c. source, e.g. a 10v d.c. source, induces microwave oscillations in the cavity. The "diode" itself consists of an N-type low resistivity substrate of the order of 10 Fm bonded to a layer of N-type Ga As; thus, although it is known as a "diode", it has in fact no
P-N junction. Upon a d.c. bias being applied to the device, current spikes are generated at approximately 10-1 second intervals which generate sinusoidal microwave oscillations in the tuned cavity. Typically such a device has a maximum output power of about 20mW and is tunable over a frequency range of approximately 9 to 10.5 GHz, corresponding to a wavelength in the region of 3 cm.
The wave guide 3 is typically a rectangular section metal tube whose internal dimensions are approximately 23 mm x 10 mm. Such a wave guide is tuned to act as a guide for microwaves of approximately 3 cm wavelength.
The attenuator 5 is of conventional construction and serves to limit the amount of microwave energy passing down the wave guide 3 from the generator 2 so that the reflected microwaves do not interfere significantly with the operation of generator 2.
Vertically polarised microwaves of wavelength X can travel down the inside of a wave guide of height 1/2A and width a along paths that are parallel to the top and bottom of the guide but reflected from side to side in the guide at a constant angle of reflection that is determined by the width a of the guide and the frequency of the signal. It is, however, observed that the apparent wavelength in the guide 3 is greater than the wavelength in free space, the relationship between these two wavelengths being: 111
(Xg)2 (at)2 (2at2 where Ag is the guide wavelength, Aa is the "free space" wavelength and a is the width of the guide.Thus, as a is gradually increased, Ag approaches Aa. This is the principle upon which horn 4 relies for launching a microwave from guide 3 into free space towards surface 9.
The probes 6, 7, 8 are illustrated in greater detail in Figure 3. These each comprise a respective probe wire 14, 15, 16, each of diameter approximately 0.5 mm, the tip of which projects approximately 0.5 mm into the wave guide 3 through a slot 17 approximately 3.21 mm wide formed in the side of the guide 3 along the centre line of one of the broad walls thereof. Surrounding each of the probe wires 14, 15, 16 are insulating bushes 18 made, for example, of a fluorinated polymer material such as polytetrafluoroethylene so as to insulate each probe wire from the wall of the wave guide 3 itself. Around the bush 18 in each case is a 50 ohm b.n.c. socket 19 of a b.n.c. connector by means of which coaxially mounted crystal detectors 20 (only part of one of which is visible in Figure 3) can be connected to the probe wires 14, 15, 16.
The internal construction of one of the crystal detectors 20 is shown diagrammatically in more detail in
Figure 4. This comprises a cartridge diode 21 containing a gold-bonded germanium crystal 22 which serves to rectify the voltage signal detected by the cathode 23 from the probe wire (e.g. 14) to which it is connected and exhibits the characteristic that its input voltage to output current relationship is approximately a "square law" for low levels of input. The sensitivity of such crystal detectors is of the order 4 to 5 millivolts per microwatt input but this decreases with increasing frequency. The body 24 of the cartridge serves as anode and is connected to lead 10, 11 or 12, as the case may be. Cathode 23 is supported in an insulating bush 25.
Instead of a crystal detector a bolometer can be used; that is to say a device incorporating a temperature sensitive element which exhibits a change in resistance as it absorbs electromagnetic radiation. Such elements may comprise a barreter, i.e. a very thin platinum wire or a thermistor, which is a small bead of semi-conducting material.
Within wave guide 3 there is set up a standing wave pattern caused by interference between the transverse wave, Y1(t), being transmitted down the wave guide from the generator 2 and the reflected wave, Y2(t), caused by reflection from surface 9. At some point A, a distance H = 1/2nA back from surface 9, where n is an integer, the equation for the voltage at A is: Yl(A) = a1,Cos 2irft where a1 is the peak amplitude and f is the frequency.At a more general point P, a distance x from point A, the corresponding equation is: Y1(p) = a1-Cos 2#(ft - A ) The reflected wave, on the other hand, is necessarily opposite in sign, but has an amplitude a2 which is smaller than a1, since the degree of reflection will in practice be less than 100%. Hence the reflected wave at a point Pwould be: Y2(p) = - a2[Cos 2#(ft - h - h -x)]
# # = - a2[Cos 2ir(ft + A )[ But Cos 2#(z - l2h = Cos 2sz, since 2h = n (an integer).
Thus Y2(p) = - a2Cos 2ar(ft +0 and by superposition
YT(t,x)= = Yl(t,x) + Y2(t.x) = a1Cos 2#(ft - X) - a2Cos 2n(ft +2), This equation describes the voltage component of the microwave standing wave pattern as detected by the probe wires 14, 15, 16. Relative movement between the surface 9 and the detector 1 alters the value of x and hence changes the standing wave pattern. Hence the position of surface 9 can be detected by monitoring changes in the standing wave pattern as will be described below.
Since crystal detectors 20 respond to the power in the wave it is convenient to consider the power present in the standing wave pattern. Since power is proportional to the voltage squared, then:
PT X YT2 X Yl2 + YR2 + YI.YR where Y1 is the incident wave voltage and YR the reflected wave voltage.Hence: PT α a1Cos2#(ft-x) a12Cos2+a2Cos2#(ft+x,) - 2a1a2Cos 2n(ft - XA)COs 27r(ft+ or PT α a1[2 + Cos4"'(ft - x) Cos4"(ft +XA)] - 2a1a2[Cos 47rft + Cos 4# x a12 + a22[Cos 47rft Cos 4# x] - a1a2[Cos 4#ft + COS4""''A] Hence::
PT = a12 + [a1Cos4# x - a1a21 [Cos4irft] - a1a2Cos44 Since the frequency f is 10 GHz and the band width of the equipment associated with the measurement of
PT is less than 1 MHz, the Cos 411' ft term is filtered out leaving:- PT X a12 - a1a2Cos 4#x or a12[1 - #Cos4# x] where r, i.e. the reflection coefficient, = 2 a2
a1.
This is a standing wave of wavelength half that of the voltage standing wave pattern and of amplitude which can vary between the maximum and minimum limits of PT = 2a12 and PT = 0 respectively (when # has a maximum value of 1).
Measurement of a standing wave can be achieved using a single probe which is moved along the wave guide. In the illustrated detector 1, however, there are three probe wires 14, 15, 16 for reasons which will appear below. The spacing between probe wires 14 and 15 measured along the wave guide 3 is about 33 mm, whilst that between probe wires 15 and 16 is about 27 mm. These spacings correspond respectively to 3/2 wavelengths separation between probe wires 14 and 15 along the standing wave pattern and 5/4 wavelengths along the standing wave pattern between probe wires 15 and 16. Although ideally it would be preferable for those spacings to be 1/2 and 1/4 wavelengths respectively the physical limitations of the diode encapsulations making this impossible; thus spacings of 3/2 and 5/4 wavelengths represent the best compromise available.Hence if the voltage detected by probe wire 14, V01, is given by the following equation: V01 = a1(1 - #Cos4# x), then the voltage, V02, detected by probe wire 15 is given by the equation:
V02 = a1(1 -I'Cos[4# x + (2n -1)#]).
= a1(1 - #Cos - V02 = a12(1 + #Cos4#x).
The voltage detected by probe wire 16, i.e. voltage V03, is given by the equation:
V03 = a12(1 - #Sin 2# x) It will be seen that by subtracting the two waveforms one from another, the resultant wave form is given by the following equation: -V012 V01 - V02 = a12(1 - Tacos 4XA) - a22(1 + Tacos 4X) = - 2a12 Tacos 44 In this way the constant term a12 is eliminated.
If, however, the two voltages are added, then the resulting waveform is:
(Vo1 + V02) = 2a12
By dividing this voltage in two and subtracting it from V03, there is obtained a voltage:
V04 = a12(1 - FSin 47F3 - (2a12 x 1/2)
= - a12rSin 4XA, i.e. a quadrature component of the wave form V01,2 and without the unwanted constant a12.
Addition and subtraction of the voltages detected by probes 6,7 and 8 is achieved by means of the
detector circuit which is indicated diagrammatically at 13 in Figure 2. Voltage V01 in line 10 is applied across load resistance 26 to amplifier 27 which has a gain factor of 10. In a similar manner voltage V02 in line 11 is applied across load resistance 28 to the input of amplifier 29 which also has a gain factor of 10. The ouputs from the amplifiers 27 and 29 are taken respectively in lines 30 and 31 and are applied to differential amplifier 32 which also has a gain factor of 10. The resultant signal in line 33 corresponds to 100 V01,2.
The signal in line 12, i.e. voltage V03, iS applied across load resistance 34 to amplifier 35, which has a gain factor of 10 and whose output signal is applied by way of line 36 to an input terminal of a differential amplifier 37 having a gain factor of 20. The output signals from amplifiers 27 and 29 in lines 30 and 31 are added by means of amplifier 38 which has a gain factor of 0.5. The output signal from amplifier 38 in line 29 is applied to the other input terminal of differential amplifier 37, the output from which in line 40 corresponds to 200 V04.
A more detailed circuit diagram of detector circuit 13 will be found in Figure 5.
The derived voltages V012 and V04 are 90" out of phase with each other. Voltage V01,2 provides an analogue indication of the displacement x of surface 9 for small displacements about a node whilst voltages V012 and
V04 are used in conjunction with each other to enable an up/down counter of conventional design to display large changes of the displacement x.
The up/down counting technique adopted is such that the counter display is incremented (or decremented) by one for changes in the displacement x equal to 8a (typically 4mm increments or decrements).
To present the output signals V01.2 and V04 in a form suitable for up-down counting with a CMOS integrated circuit counter, it is necessary to transform the characteristic sinusoidal form of output into a square wave of "high" and "low" levels of 5 volts and 0 volts respectively. The transistion between high and low levels occurs at the zero crossing poins of the sinusoid.
This transformation is achieved by Schmitt-triggering the two voltages V012 and V04.
The illustrated detector can be used for remotely detecting the level of any interface between media of differing dielectric constant. Thus, for example, it can be used to detect the level of liquid-air boundaries, liquid-liquid boundaries, solid-liquid boundaries, or air-solid boundaries. Typical applications of detectors constructed in accordance with the invention include detection of the level of molten metal in a furnace or tundish, detection of the level of liquid or solid in a tank or silo, detection of the interface between an organic liquid and an aqueous liquid, and detection of the level of solids precipitated from a liquid in a container.
Compared with instruments that employ echo-sounding techniques the detector of the invention has the advantage that stray signals (due, for example, to echoes from the walls of the container for the liquid or solid whose surface is to be detected) do not interfere with the operation of the instrument.
Moreover a high degree of accuracy of measurement can be achieved e.g. changes of level of the surface of the order of 5 micrometres can be detected.
CLAIMS (filed on 24.6.83)
1. A surface detector for remotely determining the position of a surface of a mass of material which comprises microwave generator means, wave guide means arranged to receive at one end thereof microwave energy from the generator means, means at the other end of the wave guide means for launching microwave energy into free space and for receiving reflected microwave energy from the surface
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (15)
1. A surface detector for remotely determining the position of a surface of a mass of material which comprises microwave generator means, wave guide means arranged to receive at one end thereof microwave energy from the generator means, means at the other end of the wave guide means for launching microwave energy into free space and for receiving reflected microwave energy from the surface
whose positon is to be determined, probe means mounted in the wave guide means for detecting the interference pattern set up in the wave guide means by interference between microwaves transmitted along the wave guide means from the generator means and microwaves reflected from the surface whose position is to be determined, and detector circuit means connected to and responsive to signals from the probe means for detecting changes in the interference pattern and hence relative movement between the detector and the surface whose position is to be determined.
2. A surface detector according to claim 1, in which the microwave generator means comprise a "Gunn diode".
3. A surface detector according to claim 1 or claim 2 in which the wave guide means comprises a rectangular section metal tube which is tuned to the frequency of the microwave energy produced by the microwave generator means.
4. A surface detector according to any one of claims 1 to 3, in which the means for launching microwave energy into free space comprises a horn.
5. A surface detector according to any one of claims 1 to 4, in which the probe means comprises one or more probe wires whose tip or tips project through, but are insulated from, the wall of the wave guide means into the path of the microwave energy.
6. A surface detector according to claim 5, in which the probe means includes a detector corresponding to the, or to each, probe wire which is adapted to detect and amplify voltages induiced in the probe wires by the microwave energy.
7. A surface detector according to claim 6, in which the or each detector comprises a crystal detector of the gold-bonded germanium type.
8. A surface detector according to any one of claims 5 to 7, in which the probe means comprises first and second probe wires, the spacing between the first and second probe wires measured along the wave guide means being substantially equal to (n + ) A psw where n isO or an integer, and A psw is the standing wavelength of the microwave power in the wave guide means.
9. A surface detector according to claim 8, in which the detector circuit means is arranged to amplify and then subtract the output signals from the said first and second probe wires and produce a first derived signal that varies sinusoidally with the relative movement to be measured which can be applied to a counter.
10. A surface detector according to claim 8 or claim 9, in which the probe means includes a third probe wire whose spacing from the second probe wire measured along the wave guide means is substantially equal to (n + 1/4 A psw where n and A psw are as defined.
11. A surface detector according to claim 10, in which the detector circuit means is arranged to add the output signals from the detectors for the first and second probe wires to divide this added signal by a factor of 2, and to subtract the resultant signal from the output signal from the third probe wire to give a second derived signal that is a quadrature component of the first derived signal.
12. A surface detector according to claim 11, in which the detector circuit means is arranged to amplify the output signals from the detectors for the first and second probe wires prior to addition of such signals.
13. A surface detector according to claim 11 or claim 12, in which the detector circuit means is arranged to amplify the output signal from the third probe wire prior to subtraction of the said resultant signal therefrom.
14. A surface detector according to any one of claims 11 to 12, further including an "up-down" counter arranged to be driven by the first and second derived signals.
15. A surface detector constructed and arranged substantially as herein described with particular reference to Figures 2 to 5 of the accompanying drawings.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08218635A GB2123237A (en) | 1982-06-28 | 1982-06-28 | Surface detector |
| ZA826849A ZA826849B (en) | 1982-06-28 | 1982-09-17 | Surface detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08218635A GB2123237A (en) | 1982-06-28 | 1982-06-28 | Surface detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2123237A true GB2123237A (en) | 1984-01-25 |
Family
ID=10531332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08218635A Withdrawn GB2123237A (en) | 1982-06-28 | 1982-06-28 | Surface detector |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2123237A (en) |
| ZA (1) | ZA826849B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6725718B2 (en) | 2001-02-08 | 2004-04-27 | Vega Grieshaber Kg | Method and device for the coarse differentiation between a liquid or a bulk material of a filling product present in a receptacle |
| US8730093B2 (en) | 2011-09-27 | 2014-05-20 | Rosemount Tank Radar Ab | MFPW radar level gauging with distance approximation |
| US8854253B2 (en) | 2011-09-27 | 2014-10-07 | Rosemount Tank Radar Ab | Radar level gauging with detection of moving surface |
| US8872694B2 (en) | 2010-12-30 | 2014-10-28 | Rosemount Tank Radar Ab | Radar level gauging using frequency modulated pulsed wave |
| US9513153B2 (en) | 2010-12-30 | 2016-12-06 | Rosemount Tank Radar Ab | Radar level gauging using frequency modulated pulsed wave |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1008354A (en) * | 1963-01-24 | 1965-10-27 | Bendix Corp | Measuring gauge |
| GB1289496A (en) * | 1968-09-12 | 1972-09-20 | ||
| GB1314368A (en) * | 1969-08-07 | 1973-04-18 | Bendix Corp | Liquid condition indicating device |
| GB1315045A (en) * | 1970-12-09 | 1973-04-26 | Atomic Energy Authority Uk | Fluid level locator |
| GB1345520A (en) * | 1971-04-19 | 1974-01-30 | Atomic Energy Authority Uk | Microwave interferometers |
-
1982
- 1982-06-28 GB GB08218635A patent/GB2123237A/en not_active Withdrawn
- 1982-09-17 ZA ZA826849A patent/ZA826849B/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1008354A (en) * | 1963-01-24 | 1965-10-27 | Bendix Corp | Measuring gauge |
| GB1289496A (en) * | 1968-09-12 | 1972-09-20 | ||
| GB1314368A (en) * | 1969-08-07 | 1973-04-18 | Bendix Corp | Liquid condition indicating device |
| GB1315045A (en) * | 1970-12-09 | 1973-04-26 | Atomic Energy Authority Uk | Fluid level locator |
| GB1345520A (en) * | 1971-04-19 | 1974-01-30 | Atomic Energy Authority Uk | Microwave interferometers |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6725718B2 (en) | 2001-02-08 | 2004-04-27 | Vega Grieshaber Kg | Method and device for the coarse differentiation between a liquid or a bulk material of a filling product present in a receptacle |
| US8872694B2 (en) | 2010-12-30 | 2014-10-28 | Rosemount Tank Radar Ab | Radar level gauging using frequency modulated pulsed wave |
| US9513153B2 (en) | 2010-12-30 | 2016-12-06 | Rosemount Tank Radar Ab | Radar level gauging using frequency modulated pulsed wave |
| US8730093B2 (en) | 2011-09-27 | 2014-05-20 | Rosemount Tank Radar Ab | MFPW radar level gauging with distance approximation |
| US8854253B2 (en) | 2011-09-27 | 2014-10-07 | Rosemount Tank Radar Ab | Radar level gauging with detection of moving surface |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA826849B (en) | 1983-09-28 |
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