System and method for estimating signal propagation characteristics of substance composition within predefined level range

Abstract

The invention relates to a system and a method for estimating signal propagation characteristics of a substance composition within a predefined level range. A radar measurement system includes: a transceiver; a vertically extending transmission line probe coupled to the transceiver and configured to direct a transmit signal from the transceiver through the material composition and to return a reflected signal resulting from reflection of the transmit signal, the transmission line probe having: a first probe portion, a first probe portion configured to provide a first coupling between the transmit signal and a substance composition surrounding the first probe portion; and a second probe portion configured to provide a second coupling between the transmit signal and a substance composition surrounding the second probe portion, the second coupling being weaker than the first coupling; and processing circuitry configured to estimate a signal propagation characteristic of a first level range of material composition around the first probe portion based on a timing relationship between the transmitted signal and the reflected signal and based on a known length of the first probe portion.

Description

Technical Field

[0001] The present invention relates to a radar measurement system for installation at a tank containing a material component, and a method for estimating signal propagation characteristics of a material component. Background Art

[0002] In various industrial applications, it is necessary to reliably separate different substances with different densities. As an illustrative example, the oil industry uses so-called phase separators to separate water, oil, and gas. The separated water, oil, and gas are output through different outlets, for example for recycling, discharge, or further refining. In this and other applications, it is desirable to achieve a clear separation, for example, to avoid an emulsion of water and oil being output through any one of the outlets intended to output water or oil. Therefore, it is necessary to achieve an estimation of the material composition within a predefined horizontal range in a tank, such as near the bottom of the tank. Summary of the Invention

[0003] In view of the above, it is desirable to provide an improved estimate of the signal propagation characteristics of a material component within a predefined level range. In particular, the predefined level range may be near the bottom of a tank.

[0004] Therefore, according to a first aspect of the present invention, there is provided a radar measurement system for installation at a tank containing a material composition, the material composition comprising at least a first material having a first density, a second material having a second density lower than the first density, and a third material having a third density lower than the second density, the radar measurement system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals; a vertically extending transmission line probe coupled to the transceiver and configured to guide the electromagnetic transmission signal from the transceiver at least partially through the material composition and return an electromagnetic reflection signal generated by reflection of the transmission signal at one or more impedance discontinuities encountered thereby to the transceiver, the transmission line probe having: a first probe portion extending along a first probe position at a first distance from the transceiver and a second probe position at a second distance from the transceiver; a first probe portion extending along the transmission line probe, the second distance being shorter than the first distance, the first probe portion being configured to provide a first coupling between the transmitted signal and a material component surrounding the first probe portion within a first horizontal range; and a second probe portion extending along the transmission line probe between the second probe position and a third probe position at a third distance from the transceiver, the third distance being shorter than the second distance, the second probe portion being configured to provide a second coupling between the transmitted signal and a material component surrounding the second probe portion within a second horizontal range, the second coupling being weaker than the first coupling provided by the first probe portion; and a processing circuit system coupled to the transceiver and configured to estimate a signal propagation characteristic of the first horizontal range of the material component surrounding the first probe portion based on a timing relationship between the transmitted signal and the reflected signal and based on the known length of the first probe portion.

[0005] The present invention is based on the recognition that an estimate of signal propagation characteristics within a predefined horizontal range can be used to estimate the material composition within the horizontal range in the tank. The inventors have also recognized that such an estimate of the signal propagation characteristics can be achieved using a transmission line probe that provides sufficiently low signal loss between a transceiver and the predefined horizontal range to enable a transmitted signal to reach a first impedance discontinuity at a first probe location and to enable distinguishable reflected power from reflection of the transmitted signal at the first impedance discontinuity to return to the transceiver, and also exhibits sufficient interaction with the surrounding medium within the predefined horizontal range such that the signal propagation characteristics of the first horizontal range of material composition affect the propagation velocity of the transmitted signal (and reflected signal) along the transmission line probe within the predefined horizontal range.

[0006] Thus, an estimation of the material composition within a predefined range of levels in a tank, such as near the bottom of the tank, can be achieved without requiring a special tank feedthrough or at least one additional measurement opening provided in the tank wall. Because non-standard tank feedthroughs or at least one additional measurement opening may increase cost and complexity, aspects of the present invention provide for a simplified and more cost-effective estimation of the material composition within a predefined range of levels in a tank, such as near the bottom of the tank.

[0007] In various embodiments of the radar measurement system according to the present invention, the transmission line probe may include: a probe conductor coupled to the transceiver; and a dielectric layer at least partially surrounding the probe conductor.

[0008] The dielectric layer may advantageously form a dielectric enclosure structure that extends along a substantial portion of the transmission line probe, such as along the entire length of the transmission line probe disposed within the tank.

[0009] This type of transmission line probe may be referred to as a partial external dielectric (PED) transmission line probe.

[0010] The propagation velocity of the probe along the PED transmission line is given by the effective dielectric constant ε eff Characterize the effective dielectric constant ε eff Depends on the dielectric constant ε of the dielectric closed structure int and the dielectric constant ε of the surrounding medium ext The propagation speed of the electromagnetic signal (transmitted signal and reflected signal) propagating along the PED transmission line probe is the speed of light divided by ε eff The square root of is given.

[0011] The effective dielectric constant ε of the PED transmission line probe eff The dielectric constant ε of the dielectric enclosed structure depends at least approximately on the following relation int and the dielectric constant ε of the surrounding medium ext :

[0012]

[0013] Where α is a number between 0 and 1 that indicates the degree of coupling with the surrounding medium. In the case of α = 1, the probe conductor is uncoated (thus the influence of the surrounding medium is maximized), while in the case of α = 0, the probe conductor is completely shielded from the surrounding medium (signal propagation is completely independent of the surrounding medium). It should be noted that the exact calculations may vary slightly depending on the geometry of the transmission line probe, but the important point is that the coupling with the surrounding medium in different probe sections can be adjusted to meet the requirements by at least partially surrounding the probe conductor with (the same) dielectric material of different thicknesses in different probe sections and / or by at least partially surrounding the probe conductor with different dielectric materials (with different relative permittivities) in different probe sections.

[0014] For example, the probe conductor may thus be at least partially surrounded by a relatively thin dielectric layer in the first probe part and by a relatively thick dielectric layer in the second probe part.

[0015] In an embodiment of the radar measurement system according to the present invention, the transmission line probe can advantageously include a substantially uniform coating of dielectric material, the thickness and material properties of which are selected to achieve a first coupling coefficient α1 greater than 0.1 and less than 0.5 in the first probe portion, and a second coupling coefficient α2 greater than 0.6 in the second probe portion. As an illustrative and non-limiting example, the dielectric material coating can be made of PTFE and have a thickness in the range of 1 mm to 10 mm in the first probe portion and a thickness greater than 12 mm in the second probe portion.

[0016] Alternatively, or in combination, the transmission line probe may include: a probe conductor coupled to the transceiver; and a shield conductor spaced apart from the probe conductor and extending along at least a portion of the transmission line probe. In particular, the shield conductor may extend along the second probe portion to provide a desired relatively weak coupling between the transmit signal and material components within a second horizontal range surrounding the second probe portion.

[0017] The shield conductor may be connected to electrical ground, for example by a direct conductive connection to the conductive tank roof where applicable. Alternatively, the shield conductor may be electrically floating.

[0018] In an embodiment of the radar measurement system according to the present invention, the transmission line probe may include: a third probe portion extending along the transmission line probe between the third probe position and a fourth probe position at a fourth distance from the transceiver, the fourth distance being shorter than the third distance, the third probe portion being configured to provide a third coupling between the transmitted signal and a material component within a third horizontal range surrounding the third probe portion, the third coupling being stronger than the second coupling provided by the second probe portion.

[0019] For example, the transmission line probe may include a probe conductor and a dielectric layer at least partially surrounding the probe conductor, and the thickness of the dielectric layer may be the same or thinner in the third probe portion than in the first probe portion. In one example configuration, the probe conductor may be uncoated in the third probe portion.

[0020] In embodiments where the transmission line probe has the third probe portion described above, the processing circuitry may be configured to determine a level of an interface between the second substance and the third substance in the tank based on a timing relationship between the transmit signal and a reflection signal indicative of reflection within a third level range.

[0021] Advantageously, the radar measurement system according to various embodiments of the present invention can be included in a phase separator arrangement, the phase separator arrangement further comprising: a tank elongated in a first, substantially horizontal direction and extending in the first direction between a first tank end and a second tank end; an inlet adjacent to the first tank end for receiving a flow of a material component, the material component comprising at least a liquid first material having a first density and a liquid second material having a second density lower than the first density; an overflow weir arranged at a weir position between the inlet and the second tank end; a first outlet arranged horizontally at the bottom of the tank between the inlet and the weir position for outputting the first material separated from the material component; and a second outlet arranged horizontally at the bottom of the tank between the weir position and the second tank end for outputting the second material separated from the material component. The radar measurement system can be arranged to measure the material component at a measurement position between the inlet and the weir position.

[0022] Using information available from the radar measurement system, the operation of the phase separator arrangement can be optimized. For example, the flow rate of the material component provided to the inlet can be controlled based on an estimate of the signal propagation characteristic of a first horizontal range of the material component provided by the radar measurement system. In particular, the estimate of the signal propagation characteristic can indicate the efficiency of the material component's separation into the first and second materials. If the estimate of the signal propagation characteristic indicates a separation below a predefined threshold separation, the flow rate of the material component through the inlet can be reduced, the flow of the material component through the inlet can be temporarily stopped, and / or the flow through one or more outlets can be temporarily stopped.

[0023] According to a second aspect of the present invention, a method for estimating signal propagation characteristics of a material component within a predefined first horizontal range is provided, the method comprising: generating and transmitting an electromagnetic transmit signal by a transceiver; providing the transmit signal to an upper probe end portion of a vertically extending transmission line probe, the transmission line probe having: a first probe portion, which is surrounded by the material component within the first horizontal range and is configured to provide a first coupling between the transmit signal and the material component within the first horizontal range, and a second probe portion, which is between the transceiver and the first probe portion and is configured to provide a second coupling between the transmit signal and the material component within a second horizontal range surrounding the second probe portion, the second coupling being weaker than the first coupling provided by the first probe portion; receiving, by the transceiver, an electromagnetic reflection signal from the transmission line probe, the electromagnetic reflection signal being generated by reflection of the transmit signal at one or more impedance discontinuities encountered thereby; and estimating, by a processing circuit system coupled to the transceiver, the signal propagation characteristics of the first horizontal range of the material component surrounding the first probe portion based on a timing relationship between the transmit signal and the reflection signal and based on a known length of the first probe portion.

[0024] According to various embodiments, the method may include determining, by the processing circuitry, a metric indicative of a proportion of the first substance within the first horizontal range based on the estimated signal propagation characteristics of the first horizontal range, known signal propagation characteristics of the first substance, and known signal propagation characteristics of the second substance.

[0025] Other embodiments of the second aspect of the present invention and the effects obtained by the second aspect of the present invention are largely similar to those described above for the first aspect of the present invention.

[0026] In summary, the present invention is therefore directed to a radar measurement system comprising: a transceiver; a vertically extending transmission line probe coupled to the transceiver and configured to direct a transmit signal from the transceiver through a material component and return a reflected signal resulting from a reflection of the transmit signal, the transmission line probe having: a first probe portion configured to provide a first coupling between the transmit signal and the material component surrounding the first probe portion; and a second probe portion configured to provide a second coupling between the transmit signal and the material component surrounding the second probe portion, the second coupling being weaker than the first coupling; and a processing circuit system configured to estimate signal propagation characteristics of a material component within a first horizontal range of the material component surrounding the first probe portion based on a timing relationship between the transmit signal and the reflected signal and based on a known length of the first probe portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other aspects of the present invention will now be described in more detail with reference to the accompanying drawings showing example embodiments of the invention, in which:

[0028] Figure 1 Schematically shows a phase separator arrangement comprising a radar measurement system according to an embodiment of the present invention;

[0029] Figure 2 is a schematic functional diagram of a radar measurement system according to the present invention;

[0030] Figure 3A is a schematic diagram of an example of a transmission line probe that may be included in a radar measurement system according to an example of the present invention;

[0031] Figure 3B is shown according to the position of the probe along the Figure 3A Schematic diagram of the signal coupled into the surrounding medium provided by the transmission line probe in FIG;

[0032] Figures 4A to 4B Schematically shows Figure 3A A first example configuration of a transmission line probe in;

[0033] Figures 5A to 5B Schematically shows Figure 3A A second example configuration of a transmission line probe in FIG.

[0034] Figure 6A is a schematic diagram of an example of a transmission line probe that may be included in a radar measurement system according to an example of the present invention;

[0035] Figure 6B is shown according to the position of the probe along the Figure 6A Schematic diagram of the signal coupled into the surrounding medium provided by the transmission line probe in FIG;

[0036] Figure 7 is a flow chart schematically illustrating an example of a method according to the present invention;

[0037] Figure 8 is used Figure 3A An exemplary echo curve obtained by the transmission line probe in ; and

[0038] Figure 9 is used Figure 6A Example echo curve obtained by the transmission line probe in. DETAILED DESCRIPTION

[0039] Figure 1 A phase separator arrangement 1 comprising a radar measuring system 3 according to an embodiment of the invention is schematically shown. The phase separator arrangement 1 further comprises a tank 5 which is elongated in a first, essentially horizontal direction 7 and extends in the first direction 7 between a first tank end 9 and a second tank end 11. Figure 1As shown, the tank 5 has an inlet 13 , a first outlet 15 , a second outlet 17 , an optional third outlet 19 and an overflow weir 21 .

[0040] The inlet 13 is arranged near the first tank end 9, the overflow weir 21 is arranged at the weir position 23, spaced apart from the inlet 13 in the first direction 7, the first outlet 15 is arranged horizontally at the bottom of the tank 5 between the inlet 13 and the weir position 23, the second outlet 17 is arranged horizontally at the bottom of the tank 5 between the weir position 23 and the second tank end 11, an optional third outlet 19 is arranged at the top of the tank 5, and the radar measurement system 3 is arranged horizontally at the measurement position 25 between the inlet 13 and the weir position 23.

[0041] When the phase separator arrangement 1 is in use, a stream of material components is received through the inlet 13. The material components include at least a liquid first substance 27 having a first density and a liquid second substance 29 having a second density lower than the first density. The first substance 27 may be, for example, water, and the second substance 29 may be, for example, oil. Upon entering the tank 5 through the inlet, the material components may form an emulsion 31 of the first substance 27 and the second substance 29. As the emulsion 31 advances through the tank at an appropriate rate in a horizontal first direction 7, it separates at the bottom of the tank 5 into pure first substance 27, with pure second substance 29 floating on top of the first substance 27. An emulsion boundary layer may remain between the separated layers of the first and second substances 27, 29. The first substance 27 is discharged through the first outlet 15, and the second substance 29, after flowing over the overflow weir 21, is discharged through the second outlet 17. A third gaseous substance 33 may be discharged through the third outlet 19.

[0042] like Figure 1As schematically indicated in FIG, the exemplary radar measurement system 3 includes a vertically extending transmission line probe 35 having a first probe portion 37, a second probe portion 39, and an optional third probe portion 41. In this exemplary configuration, the first probe portion 37 can be used to estimate signal propagation properties, such as dielectric constant, of a substance component within a first horizontal range surrounding the first probe portion 37, and the third probe portion 41 can be used to determine the level of a second substance 29 (such as oil) in the tank 5. One or both of these measurements can be used to control the operation of the phase separator arrangement 1, for example by controlling the flow rate of the substance component at the inlet 13. If the estimated signal propagation properties within the first horizontal range surrounding the first probe portion 37 indicate the presence of a mixture of the first substance 27 and the second substance 29 at the bottom of the tank 5 at the first outlet 15, the first outlet 15 can be closed and the flow of the substance component at the inlet 13 can be stopped to ensure that the second substance 29 (such as oil) is not discharged into the environment through the first outlet 15. By using a radar measurement system 3 according to an embodiment of the present invention, improved operation of the phase separation device 1 can thus be provided without requiring additional openings in the tank 5.

[0043] Figure 2 is a schematic functional diagram of a radar measurement system 3 according to the present invention. Figure 2 The radar measurement system 3 includes the above-mentioned transmission line probe 35, a transceiver 43 and a processing circuit system 45. The transceiver 43 is coupled to the transmission line probe 35 and is configured to generate an electromagnetic transmission signal S T And transmit it to the transmission line probe 35. Transmit signal S T Then it is guided by the transmission line probe 35 and the transmission signal S T In the transmitted signal S T The electromagnetic emission signal S is generated by reflection from one or more impedance discontinuities encountered. R The reflected signal S is guided back to the transceiver 43 by the transmission line probe 35. The transceiver 43 is configured to receive the reflected signal S R By using techniques known per se to a person skilled in the art to evaluate the emission signal S T With the reflected signal S R The processing circuit system 45 can be configured to estimate the distance of the reference position at the interface between the transceiver 43 and the transmission line probe 35 from one or more impedance discontinuities, and / or the distance between the impedance discontinuities. T (and the reflected signal S R ) The distance estimated by the time of flight of the probe 35 along the transmission line is compared with the corresponding known distance to estimate the transmitted signal S T (and the reflected signal S RFrom the estimated propagation velocity, another signal propagation characteristic, such as the (average) dielectric constant, can be estimated, and / or information about the transmitted signal S can be derived. T (and the reflected signal S R ) Conclusions about the composition of the material that has been disseminated.

[0044] Figure 3A is a schematic diagram of an example of a transmission line probe 35 that may be included in a radar measurement system 3 according to an example of the present invention. Figure 3A The transmission line probe 35 in FIG. 3 has a first probe portion 37 and a second probe portion 39. The first probe portion 37 extends along the transmission line probe 35 between a first probe position 47 and a second probe position 49, with the second probe position 49 being closer to the probe upper end 51 than the first probe position 47. The first probe position 37 is defined by an impedance discontinuity, which can be provided, for example, by the probe lower end 53 or by a reference impedance discontinuity spaced apart from the probe lower end 53. The second probe portion 39 extends along the transmission line probe 35 between the second probe position 49 and a third probe position 55, with the third probe position 55 being closer to the probe upper end 51 than the second probe position 49.

[0045] The first probe portion 37 is configured to provide a transmission signal S directed by the transmission line probe 35 through the material composition. T The first coupling between the first probe portion 37 and the material component within the first horizontal range around the first probe portion 37, and the second probe portion 39 is configured to provide a transmission signal S guided by the transmission line probe 35 through the material component. T A second coupling with material components within a second horizontal range surrounding the first probe portion 39. The second coupling provided by the second probe portion 39 is weaker than the first coupling provided by the first probe portion 37.

[0046] Figure 3B The diagram schematically shows the relationship between the position z along the probe 35 (the distance from the probe upper end 51) and the position z along the probe 35. Figure 3A The transmission line probe 35 in FIG. 3 provides an exemplary signal coupled to the surrounding medium.

[0047] exist Figure 3B In the example, the signal coupled to the surrounding medium is represented by the coupling coefficient α, which can be a number between 0 and 1. A value of 0 indicates that the transmitted signal S T There is no coupling with the material components surrounding the transmission line probe 35, and a value of 1 indicates maximum coupling. Maximum coupling for a given transmission line probe 35 is achieved when one or more probe conductors are uncoated and unshielded, thereby allowing maximum interaction with the surrounding material components.

[0048] When the transmitting signal S TWhen there is no coupling between the transmission line probe 35 and the material components surrounding the (part of) the transmission line probe 35, there will be no signal attenuation due to the interaction of the transmission signal with the material components, and the signal propagation characteristics of the material components (such as the dielectric constant) will not affect the transmission signal S guided by the (part of) the transmission line probe 35. T (or reflected signal) propagation speed.

[0049] Figures 4A to 4B Schematically shows Figure 3A A first example configuration of the transmission line probe 35 is shown in FIG. Figure 4A is a schematic (not to scale) side view of the configuration of the transmission line probe 35, Figure 4B Schematically shown Figure 4A 1 and 2 are cross sections of the transmission line probe 35 taken along lines A to A' and B to B', respectively.

[0050] exist Figures 4A to 4B In the first example configuration shown, the transmission line probe 35 includes a transceiver 43 ( Figures 4A to 4B The probe conductor 57 (not shown) and the dielectric layer 59 surrounding the probe conductor 57. Figures 4A to 4B In the example configuration of the dielectric layer 59, the dielectric layer 59 is configured to provide the transmission signal S T The first coupling between the first probe portion 37 and the material components within the first horizontal range and providing the transmission signal S T A second coupling is provided with respect to a material component within a second horizontal range surrounding second probe portion 39. In this example configuration, dielectric layer 59 has a first thickness d1 in first probe portion 37 and a second thickness d2 in second probe portion 39, which is greater than first thickness d1. In this example configuration, dielectric material 59 in first probe portion 37 and second probe portion 39 can be the same, such as PTFE. In an alternative configuration, different dielectric materials with different dielectric constants can be present in first probe portion 37 and second probe portion 39. In this case, by using a dielectric material with a higher dielectric constant in first probe portion 37 than in second probe portion 39, the difference in dielectric material thickness between the probe portions can be smaller, or even the dielectric material thickness in first probe portion 37 and second probe portion 39 can be the same.

[0051] Figures 5A to 5B Schematically shows Figure 3A A second example configuration of the transmission line probe 35 is shown in FIG. Figure 5A is a schematic (not to scale) side view of the configuration of the transmission line probe 35, Figure 5B Schematically shown Figure 5A 1 and 2 are cross sections of the transmission line probe 35 taken along lines A to A' and B to B', respectively.

[0052] exist Figures 5A to 5B In the second example configuration shown, the transmission line probe 35 includes a transceiver 43 ( Figures 5A to 5B The probe conductor 57 (not shown) and the dielectric layer 59 surrounding the probe conductor 57. Figures 5A to 5B In the exemplary configuration of FIG, the transmission line probe 35 further includes a shield conductor 61 that is separated from the probe conductor 57 by the dielectric layer 59 and extends along the second probe portion 39. Figures 5A to 5B The shield conductor 61 in the embodiment can substantially eliminate the transmission signal S T The second coupling with the material components in the second horizontal range surrounding the second probe portion 39 makes the signal propagation along the second probe portion 39 substantially independent of the propagation characteristics of the surrounding material components in the second horizontal range.

[0053] Figure 6A is a schematic diagram of an example of a transmission line probe 35 that may be included in a radar measurement system 3 according to an example of the present invention. Figure 6A The transmission line probe 35 in FIG. 3 has a first probe portion 37, a second probe portion 39, and a third probe portion 41. The third probe portion 41 extends along the transmission line probe 35 between a third probe position 55 and a fourth probe position 63. The fourth probe position 63 is closer to the probe upper end 51 than the third probe position 55.

[0054] The third probe portion 41 is configured to provide a transmission signal S directed by the transmission line probe 35 through the material component. T A third coupling with material components within a third horizontal range around the third probe portion 41. The third coupling provided by the third probe portion 41 is stronger than the second coupling provided by the second probe portion 39, and may also advantageously be stronger than the first coupling provided by the first probe portion 37.

[0055] Figure 6B The diagram schematically shows the relationship between the position z along the probe 35 (the distance from the probe upper end 51) and the position z along the probe 35. Figure 6A The transmission line probe 35 in FIG. 3 provides an exemplary signal coupled to the surrounding medium. Figures 4A to 4B and Figures 5A to 5B The same approach achieves different couplings of different probe parts in the probe configuration.

[0056] Now refer to Figure 7 The flowchart in describes a method according to an example of the present invention. As indicated herein, reference may also be made to other drawings.

[0057] Reference Figure 7 , electromagnetic emission signal S TThe signal S is generated and transmitted 101 by the transceiver 43. T It may be provided, for example, in the form of a pulse train and / or as a continuous signal with a time-varying frequency, which is known per se to a person skilled in the art.

[0058] Transmit signal S T is provided 102 to the probe upper end 51 of a vertically extending transmission line probe 35, the transmission line probe 35 having a first probe portion 37 surrounded by a material component within a first horizontal range and configured to provide a transmission signal S T and a second probe portion 39, which is between the transceiver 43 and the first probe portion 37 and is configured to provide a transmission signal S T A second coupling with material components within a second horizontal range surrounding the second probe portion 39 , the second coupling being weaker than the first coupling provided by the first probe portion 37 .

[0059] The electromagnetic reflection signal S is generated by the reflection of the transmitted signal at one or more impedance discontinuities encountered thereby. R Received 103 by transceiver 43 from transmission line probe 35 .

[0060] Thereafter, the processing circuit system 45 processes the transmitted signal S based on the transmitted signal S. T With the reflected signal S R Based on the timing relationship between the first probe portion 37 and the known length of the first probe portion 37, signal propagation properties of a first horizontal range of material compositions surrounding the first probe portion 37, such as a (average) dielectric constant, are estimated 104.

[0061] Figure 8 is used Figure 3A An exemplary echo curve 65 obtained by the transmission line probe 35 in FIG. The echo curve showing the relationship between the flight time t of each echo and the amplitude A of the echo signal can be obtained, for example, using a time expansion technique, which is itself well known in the field of level measurement using pulsed electromagnetic signals. Figure 8 As can be seen from the schematic echo curve 65 in FIG, there are a first echo peak 67, a second echo peak 69 and a third echo peak 71. The first echo peak 67 is generated by the transmitted signal S T A reflection occurs at the impedance discontinuity provided by the connection between the transceiver 43 and the probe upper end 51. This echo peak 67 is used as a reference position to indicate the top of the tank 5 and is sometimes referred to as a reference pulse. Figure 8 In the exemplary echo curve 65 in FIG. 1 , the second echo peak 69 is generated by the transmitted signal S TA reflection at the optional impedance discontinuity at the second probe location 49, which indicates the interface between the first probe portion 37 and the second probe portion 39, results. The third echo peak 71 is generated by the transmit signal S T A reflection occurs at the impedance discontinuity defining the first probe position 47. As described above, this impedance discontinuity may be provided, for example, by the lower end of the transmission line probe 35. It should be noted that there is no significant echo peak between the first echo peak 67 and the second echo peak, despite the use of Figure 3A The probe configuration in Figure 1 In the example application, the transmitting signal S T The second probe portion 39 of the transmission line probe 35 can be guided through the two material interfaces (from the third material 33 to the second material 29, and from the second material 29 to the first material 27). In this example, due to the (very) weak coupling (low α), the transmission signal S T Passing through these material interfaces does not see any significant change in the impedance of the transmission line probe 35. Consequently, very little signal strength is lost along the second probe portion 39, providing a relatively strong and easily detectable echo peak.

[0062] Therefore, the "electrical distance" between the first probe position 47 and the second probe position 49 can be determined based on the flight time difference Δt for the second echo peak 69 and the third echo peak, respectively. The electrical distance thus determined is based on the propagation speed of the transmitted signal and the flight time difference Δt of the first horizontal range of the material composition surrounding the first probe part 37. Therefore, the propagation speed can be estimated based on the electrical distance (or flight time difference) and the known length of the first probe part 37 (the physical distance between the first probe position 47 and the second probe position 49). Based on the propagation speed, the signal propagation characteristics of the first horizontal range (such as the average relative dielectric constant) can be estimated. Conversely, conclusions about the material composition within the first horizontal range can be drawn based on the signal propagation characteristics. For example, as in Figure 1 In the case of the phase separator arrangement 1 in FIG. 1 , it is possible to determine whether the first probe portion 37 is surrounded by pure water or an oil-water emulsion, and if so, the emulsion ratio. In applications where the first substance is water or another substance with a very high dielectric constant, it may be beneficial to provide the first probe portion with a thin coating of a dielectric material such as PTFE.

[0063] As an alternative to estimating the signal propagation characteristics of the first horizontal range based on the electrical distance between the first probe position 47 and the second probe position 49, the electrical distance from the first echo peak 67 (reference echo peak) to the echo peak 71 represented by the transmitted signal S TReflection occurs at the impedance discontinuity defining the first probe location 47. When the second coupling provided by the second probe portion 39 is weak enough to allow the surrounding medium to transmit the signal S T This is possible when the influence of the propagation velocity along the second probe portion 39 is negligible.

[0064] Alternatively, and depending on the configuration of the transmission line probe 35, the level of the interface between the second substance 29 (such as oil) and the third substance 33 (such as gaseous tank atmosphere) in the tank 5 may be determined based on the transmitted signal S T With the reflected signal S R The timing relationship between the reflection signal S is determined 105. R instruct Figure 6A Reflections within a third horizontal range around the third probe portion 41 of the transmission line probe configuration.

[0065] Figure 9 is used Figure 6A An exemplary echo curve 73 obtained by the transmission line probe 35 in FIG. Figure 8 In addition to the echo peak of the echo curve 65 in FIG, for the same measurement situation, the echo curve 73 obtained using this probe configuration contains the peak of the transmitted signal S T An additional fourth echo peak 75 is generated by reflection at the impedance discontinuity provided by the interface between the second substance 29 (such as oil) and the third substance 33 (such as the gaseous tank atmosphere). Using this probe configuration, a single transmission line probe 35 can be used to determine signal propagation characteristics within a first level range based on the flight time difference Δt1 indicated by the second echo peak 69 and the third echo peak 71, and the level of the second substance 29 in the tank 5 can be determined based on the flight time difference Δt2 indicated by the first echo peak 67 and the fourth echo peak 75.

[0066] Those skilled in the art will appreciate that the present invention is by no means limited to the preferred embodiments described above. For example, other probe arrangements are also feasible.

[0067] "Matter" is generally not limited to any particular material phase and can therefore include solids, liquids, and gases. Some examples of matter could be various petroleum products, water, sludge, or sand.

[0068] A "transceiver" may be one functional unit capable of transmitting and receiving electromagnetic signals, or may be a system comprising separate transmitter and receiver units.

[0069] A can may be any container or vessel capable of holding a product and may be metallic or partially or completely non-metallic, open, semi-open or closed.

Claims

1. A radar measurement system for installation at a tank containing material components, the material components comprising at least a first material having a first density, a second material having a second density lower than the first density, and a third material having a third density lower than the second density, the radar measurement system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals; a vertically extending transmission line probe coupled to the transceiver and configured to direct an electromagnetic transmit signal from the transceiver at least partially through the material component and return an electromagnetic reflection signal generated by reflection of the transmit signal at one or more impedance discontinuities encountered thereby to the transceiver, the transmission line probe having: a first probe portion extending along the transmission line probe between a first probe position defined by an impedance discontinuity at a first distance from the transceiver and a second probe position at a second distance from the transceiver, the second distance being shorter than the first distance, the first probe portion being configured to provide a first coupling between the transmit signal and a component of the material within a first horizontal range surrounding the first probe portion; as well as a second probe portion extending along the transmission line probe between the second probe position and a third probe position at a third distance from the transceiver, the third distance being shorter than the second distance, the second probe portion being configured to provide a second coupling between the transmit signal and a component of the material surrounding the second probe portion within a second horizontal range, the second coupling being weaker than the first coupling provided by the first probe portion; as well as Processing circuitry is coupled to the transceiver and configured to estimate signal propagation characteristics of the first horizontal range of the material composition surrounding the first probe portion based on a timing relationship between the transmitted signal and the reflected signal and based on a known length of the first probe portion.

2. The radar measurement system of claim 1 , wherein the processing circuit system is configured to determine a metric indicating a proportion of the first substance within the first horizontal range based on the estimated signal propagation characteristics of the first horizontal range, the known signal propagation characteristics of the first substance, and the known signal propagation characteristics of the second substance.

3. The radar measurement system according to claim 1 or 2, wherein: The transmission line probe extends between an upper probe end coupled to the transceiver and a lower probe end, the first probe position being located at the lower probe end.

4. The radar measurement system according to claim 1 or 2, wherein the second probe part is configured so that the second coupling is sufficiently weak so that a propagation speed of the transmitted signal along the second probe part is substantially independent of signal propagation characteristics of a second horizontal range of the material components surrounding the second probe part.

5. The radar measurement system according to claim 1 or 2, wherein the transmission line probe comprises: a probe conductor coupled to the transceiver; as well as A dielectric layer at least partially surrounds the probe conductor. 6 . The radar measurement system of claim 5 , wherein the dielectric layer completely surrounds the probe conductor in the first probe part and the second probe part.

7. The radar measurement system according to claim 5, wherein the dielectric layer is configured to provide the first coupling between the transmission signal and the material components within the first horizontal range surrounding the first probe part, and to provide the second coupling between the transmission signal and the material components within the second horizontal range surrounding the second probe part. 8 . The radar measurement system of claim 7 , wherein the dielectric layer is thicker in the second probe portion than in the first probe portion.

9. The radar measurement system according to claim 1 or 2, wherein the transmission line probe comprises: a probe conductor coupled to the transceiver; as well as A shield conductor is spaced apart from the probe conductor and extends along at least a portion of the transmission line probe.

10. The radar measurement system according to claim 1 or 2, wherein the transmission line probe comprises: and a third probe portion extending along the transmission line probe between the third probe position and a fourth probe position at a fourth distance from the transceiver, the fourth distance being shorter than the third distance, the third probe portion being configured to provide a third coupling between the transmit signal and the material components within a third horizontal range surrounding the third probe portion, the third coupling being stronger than the second coupling provided by the second probe portion.

11. The radar measurement system of claim 10, wherein the processing circuit system is configured to: A level of an interface between the second substance and the third substance in the tank is determined based on a timing relationship between the transmit signal and the reflection signal indicative of reflection within the third level range.

12. A phase separator arrangement comprising: a tank elongated in a first, substantially horizontal direction and extending between a first tank end and a second tank end in the first direction; an inlet adjacent the first tank end for receiving a flow of a material composition, the material composition comprising at least a liquid first material having a first density and a liquid second material having a second density lower than the first density; an overflow weir disposed at a weir location between the inlet and the second tank end; a first outlet disposed horizontally at the bottom of the tank between the inlet and the weir location for outputting a first substance separated from the substance components; a second outlet arranged horizontally at the bottom of the tank between the weir location and the second tank end for outputting a second substance separated from the substance components; as well as A radar measurement system according to claim 1 or 2, arranged to measure the material composition at a measurement position between the inlet and the weir position.

13. A phase separator arrangement according to claim 12, wherein The radar measurement system is arranged horizontally between the first outlet and the weir location.

14. A method for estimating a signal propagation characteristic of a material component within a predefined first level range, the method comprising: An electromagnetic transmission signal is generated and transmitted by a transceiver; Providing the transmission signal to an upper probe end portion of a vertically extending transmission line probe, the transmission line probe having: a first probe portion, which is surrounded by the material components within the first horizontal range and is configured to provide a first coupling between the transmission signal and the material components within the first horizontal range; and a second probe portion, which is between the transceiver and the first probe portion and is configured to provide a second coupling between the transmission signal and the material components within a second horizontal range surrounding the second probe portion, the second coupling being weaker than the first coupling provided by the first probe portion; receiving, by the transceiver, from the transmission line probe, an electromagnetic reflection signal resulting from reflection of the transmit signal at one or more impedance discontinuities encountered thereby; as well as Signal propagation characteristics of the first horizontal range of the material composition surrounding the first probe portion are estimated by processing circuitry coupled to the transceiver based on a timing relationship between the transmitted signal and the reflected signal and based on a known length of the first probe portion.

15. The method according to claim 14, comprising: A metric indicative of a proportion of the first substance within a first level range is determined by the processing circuitry based on the estimated signal propagation characteristics of the first level range, known signal propagation characteristics of the first substance, and known signal propagation characteristics of a second substance.

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