JP2000241232A - Interface measuring method and microwave interface meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interface measuring method and an interface measuring meter which enable measurement without being affected by bubbles and neighboring structure when an interface is not clear. SOLUTION: A microwave is made to propagate in a part between two antennas 14-8, 14-6 which are arranged in a supernatant liquid phase 73 and have a known interval, and the propagation phase delay is measured. A microwave is made to propagate in a part between two antennas 14-4, 14-2 which are arranged in a sludge phase 72 and have a known interval, and the propagation phase delay is measured. A microwave is made to propagate in a part between two antennas 14-6, 14-4 which are arranged in the phase 73 and the phase 72, respectively, sandwiching the interface 74, and have a known interval, and the propagation phase delay is measured. The interface position is obtained from the respective propagation phase delays by a specified operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface measuring method for detecting an interface position between a first phase and a second phase having different dielectric constants using a microwave, and a microwave interface measuring instrument.
For example, the present invention relates to an interface measurement method and a microwave interface measurement meter capable of measuring an interface position in a sludge settling tank, various settling tanks, a solution separation layer, and a solid-liquid separation layer.

[0002]

2. Description of the Related Art For example, a measuring instrument using ultrasonic waves has been conventionally used for detecting an interface position of a sludge settling tank. FIG. 4 shows an interface measurement meter using this ultrasonic wave. In this figure, reference numeral 70 denotes a sludge settling tank, 72 denotes a sludge phase, 73 denotes a supernatant liquid phase, and 74 denotes a sludge interface as a boundary between the sludge phase 72 and the supernatant liquid phase 73 in the cross section of the sludge settling tank 70. Is shown. Reference numeral 80 denotes an ultrasonic interface measurement meter.
Is an ultrasonic transceiver 82 disposed in the supernatant liquid phase 73.
And a measuring instrument main body 84. When an ultrasonic pulse is transmitted from the ultrasonic transmitter / receiver 82 by an electric signal from the measuring instrument body 84, the ultrasonic pulse is reflected on the sludge interface 74 and the bottom surface 76 of the sludge settling basin 70, and the ultrasonic pulse propagates in the supernatant liquid phase 73. , Are again received by the ultrasonic transceiver 82. These reflected pulses are converted into electric signals, output to the measuring instrument main body 84, the electric signals are analyzed by the measuring instrument main body 84 to obtain a reflection pattern, and the ultrasonic wave reflected at the sludge interface 74 based on this is obtained. The distance D between the ultrasonic transmitter / receiver 82 and the sludge interface 74 is determined from the time required for returning to the position, and the interface position is determined.

[0003]

However, in such a conventional interface measuring instrument using ultrasonic waves, the ultrasonic waves cannot be propagated normally due to the influence of air bubbles, or the sludge phase 72 and the supernatant liquid phase 73 are separated. If they are not clearly separated, there is a problem that it is impossible to determine the position of the sludge interface 74 because the reflected ultrasonic waves from the sludge interface 74 cannot be sufficiently obtained. In addition, there is a problem that an installation place of the ultrasonic transceiver 82 is restricted because the reflected wave from a structure near the ultrasonic transceiver 82 adversely affects the installation place.

[0004] The present invention has been made in view of the above problems,
It is an object of the present invention to provide an interface measurement method and an interface measurement meter which are not affected by bubbles or nearby structures and can perform measurement even if the interface is not clear. And

[0005]

In order to achieve the above object, the present invention provides an interface measuring method for detecting an interface position between a first phase and a second phase having different dielectric constants. Microwaves are propagated between two antennas in a phase and at a known distance from each other, and the propagation phase delay is measured. Between two antennas both in the second phase and at a known distance from each other The microwave is propagated to measure the propagation phase delay, and the microwave is propagated between two antennas in the first phase and the second phase, each having a known distance therebetween, across the interface. , Measuring its propagation phase lag,
An interface position is obtained from each propagation phase delay.

The present invention is also an interface meter for detecting an interface position between a first phase and a second phase having different dielectric constants, both of which are in the first phase and have a known distance from each other. A first antenna set consisting of two antennas and transmitting microwaves from one antenna to the other,
A second antenna set consisting of two antennas in a phase and having a known distance from each other, and transmitting microwaves from one antenna to the other antenna; And a third antenna set for transmitting microwaves from one antenna to the other antenna, and a propagation phase delay of each antenna set are determined. And a measuring instrument body for obtaining the interface position from the propagation phase delay.

[0007] The propagation phase delay θ1 that occurs when propagating through two antennas in the first phase is determined by setting the distance between the antennas to L
1, if the frequency is f, the relative permittivity of the first phase is εa, and the speed of light in vacuum is c,

[0008]

(Equation 1) It can be expressed as.

Similarly, the propagation phase delay θ2 that occurs when two antennas in the second phase are propagated is represented by the following formula, where L2 is the distance between the antennas and εb is the relative permittivity of the second phase.

[0010]

(Equation 2) It can be expressed as.

Similarly, a propagation phase delay θ12 that occurs when two antennas in the first phase and the two antennas in the second phase sandwich the interface, respectively, is given by:

[0012]

(Equation 3) Becomes Where h is the distance between the antenna in the second phase and the interface.

H can be obtained by eliminating εa and εb using the above equations (1), (2) and (3). Therefore, the interface position can be obtained from the position of the antenna.

Since there is a correlation between the concentration and the dielectric constant, the interface position between two phases having different concentrations can be detected.

Each of the first to third antenna sets includes two antennas appropriately selected from a plurality of antennas mounted at predetermined intervals on a mounting portion extending substantially perpendicular to the interface. Good to be. It is preferable that every other of the plurality of antennas is mounted in the same direction with respect to the axis of the mounting portion, and that adjacent antennas are mounted at positions facing each other with respect to the axis of the mounting portion. Since the positions of the adjacent antennas are different, microwaves can be transmitted from a certain antenna to both the adjacent antenna and the adjacent antenna. Therefore, a set of antennas can be selected between adjacent antennas or every other antenna according to the amount of microwave attenuation. Further, when the position of the interface is near a certain antenna, the antenna set including the antenna may not have a difference from the propagation delay time in the phase not including the interface. In this case, if a pair is formed by the antennas on both sides of the antenna near the interface, the interface will be located between the two antennas, so there will be a difference from the propagation delay time in the phase not including the interface, The interface position can be obtained from the above equations (1), (2) and (3).

[0016] Alternatively, each of the first to third antenna sets may be composed of two antennas selected from four antennas arranged to form a quadrangle by a mounting portion.

Further, the microwave interferometer may further include an elevating device for elevating and lowering the mounting portion.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a first embodiment of the present invention.

In the figure, reference numeral 10 denotes a microwave interface meter, which is an antenna mounting pipe (mounting portion) 12 and a plurality of patches mounted on the antenna mounting pipe 12 at predetermined intervals L. , And 14-8, and a measuring instrument body 16. In this embodiment, the tip of the antenna mounting pipe 12 is installed on the bottom surface 76b near the sludge extraction port 78 of the sludge settling tank 70, and the antenna mounting pipe 12 is fixed to the sludge settling tank 70.
The transmitting / receiving antennas 14-1, 14-2, 14-3,...
14-8 are mounted in the same direction with respect to the axis of the antenna mounting pipe 12 for every other antenna, and are mounted on adjacent antennas at positions facing each other with respect to the axis of the antenna mounting pipe 12.

Each transmitting / receiving antenna 14-1, 14-2, 1
4-3,..., 14-8 are the antenna mounting pipes 1 respectively.
2 is connected to the measuring instrument main body 16 by a signal line passing therethrough.

FIG. 2 is a block diagram of the measuring instrument body 16. The measuring instrument body 16 includes a reference oscillator 18 composed of a crystal oscillator or the like, a frequency divider 20, a PLL synthesizer 22,
4, amplifier 25, transmission antenna selection switch 26, attenuator 28, reception antenna selection switch 30, amplifier 31,
It includes mixers 32 and 34, band-pass filters 36 and 38, amplifiers 40 and 44, a digital signal processor 46 composed of an ASIC, a CPU 48, a memory 49, and the like.
167 and JP-A-10-142168.

That is, the signal from the reference oscillator 18 is frequency-divided by the frequency divider 20, phase-locked to the frequency f1 by the PLL synthesizer 22, and
At 4, the phase is locked to the frequency f2 close to f1. P
The signal of the frequency f1 from the LL synthesizer 22 is converted into a microwave by any of the transmitting / receiving antennas 14-1,..., 14-8 selected by the transmitting antenna selection switch 26 and transmitted. When the microwave propagating in the sludge sedimentation basin 70 is received by any of the transmission / reception antennas 14-1 to 14-8 selected by the reception antenna selection switch 30, the microwave is amplified by the amplifier 31 and then mixed by the mixer 32.
Is mixed with the signal of frequency f2 from the PLL synthesizer 24, passes through the band-pass filter 36, and is converted into a low-frequency signal f1-f2. This low frequency signal is supplied to the amplifier 40
, And input to the digital signal processor 46. At the same time, the signal from the PLL synthesizer 22 is directly input to the mixer 34, and the PLL synthesizer 24
, And is converted to a low-frequency signal f1-f2 through a band-pass filter 38, passed through an amplifier 44, and input to a digital signal processor 46. In the digital signal processor 46, based on the clock signal from the reference oscillator 18, the amplifier 40 and the amplifier 4
4 by counting the time difference between the digital waveforms input from the PLL synthesizer 22 and the signal transmitted through the sludge sedimentation basin 70 from the PLL synthesizer 22 and the PLL synthesizer 22
Can determine the phase delay θ1 of the signal transmitted directly without passing through the sludge settling tank 70.

Further, between the transmission antenna selection switch 26 and the reception antenna selection switch 30, the selection of these changeover switches allows the transmission / reception antenna 14-1,
... not connected to 14-8, a reference line 29 is provided with an attenuator 28 that provides the same attenuation as the signal propagated through the sludge settling basin 70. By switching the transmission antenna selection switch 26 and the reception antenna selection switch 30, the PLL synthesizer 22 and the amplifier 25
8, the signal that has passed through the amplifier 31, the mixer 32, the band-pass filter 36, and the amplifier 40 is transmitted from the PLL synthesizer 22 to the sludge sedimentation tank 70 in the digital signal processor 46 in the same manner as described above. The phase delay θ2 with the signal sent directly without counting is counted. Since the phase delay θ1 and the phase delay θ2 include a drift of the same measurement system, an offset error, an error due to temperature, and an error due to variation in the analog circuit, θ1
By subtracting θ2 from the above and adding a known phase delay based on the electrical length of the reference line, the above error can be canceled.

In this way, the measuring instrument main body 16 can measure the propagation phase delay without error, and by appropriately switching the transmission antenna selection switch 26 and the reception antenna selection switch 30, the transmission / reception antenna for transmitting / receiving. .. 14-8 can be appropriately selected.

The operation of the microwave interface meter 10 configured as described above will be described.

The transmission antenna selection switch 26 and the reception antenna selection switch 3
It is assumed that the microwave is propagated from the transmission / reception antenna 14-8 by selection of 0, and the reception is performed by the transmission / reception antenna 14-6. The transmitting / receiving antenna 14- in the supernatant liquid phase 73
8 when the microwave propagates from the transmission antenna 8 to the transmission / reception antenna 14-6, assuming that the frequency is f, the relative permittivity of the supernatant liquid phase 73 is εa, and the speed of light in a vacuum is c, the transmission / reception antenna 14-8 And transmitting / receiving antenna 14-
Since the distance between 6 is 2L,

[0027]

(Equation 4) It can be expressed as.

Similarly, the microwave from the transmitting / receiving antenna 14-4 is propagated by the signal from the measuring instrument body 16 by the selection of the transmitting antenna selecting switch 26 and the receiving antenna selecting switch 30, and the reception is performed by the transmitting / receiving antenna 14-2. Let it be done. The propagation phase delay θ42 when the microwave propagates from the transmitting / receiving antenna 14-4 to the transmitting / receiving antenna 14-2 in the sludge phase 72 is f, the relative permittivity of the sludge phase εb, and the speed of light in a vacuum c. Then

[0029]

(Equation 5) It can be expressed as.

The transmission antenna selection switch 26 and the reception antenna selection switch 3
It is assumed that the microwave is propagated from the transmitting / receiving antenna 14-6 by selection of 0, and the receiving is performed by the transmitting / receiving antenna 14-4. The propagation phase delay θ64 when the microwave propagates from the transmitting / receiving antenna 14-6 in the supernatant liquid phase 73 to the transmitting / receiving antenna 14-4 in the sludge phase 72 with the sludge interface 74 interposed between the transmitting / receiving antenna 14-4 Assuming that the distance to the sludge interface 74 is h,

[0031]

(Equation 6) It can be expressed as. From equations (4), (5) and (6), ε
When a and εb are eliminated and h is obtained,

[0032]

(Equation 7) The interface position h can be calculated from the phase delays θ86, θ64, and θ42.

As described above, the transmitting and receiving antennas 14-8, 14
H can be obtained using −6, 14-4, and 14-2.

At the time of actual measurement, the transmission antenna selection switch 26 and the reception antenna selection switch 30 are sequentially switched so that the microwave is transmitted from the transmission / reception antenna 14-8 and received by the transmission / reception antenna 14-6. The propagation phase delay θ86 is obtained, and the transmitting / receiving antennas 14-7, 1
4-6,..., And microwaves are transmitted and received by transmission / reception antennas 14-5, 14-4,. As shown in the example of the figure, the sludge interface 74 has the antennas 14-4 and 14-.
5, among the obtained propagation phase delays θ86, θ75, θ64, θ53, θ42, and θ31, θ86 and θ75 are the phase delays obtained by propagating the same supernatant liquid phase 73. Should take approximately the same value. The supernatant liquid phase 73 has substantially the same relative dielectric constant as water (εa = 81), and a propagation phase delay corresponding thereto is obtained. On the other hand, since θ42 and θ31 are phase delays obtained by propagating the same sludge phase 72, they take almost the same value. Since the substance constituting the sludge of the sludge phase 72 usually has a much smaller dielectric constant than water, θ42 and θ31 are much smaller than θ86 and θ75. Since θ64 and θ53 should take an intermediate value between them, the transmitting and receiving antennas 14-6 and 14-4
It can be seen that there is a sludge interface 74 between the transmitting and receiving antennas 14-5 and 14-3. Therefore, θ8, which was definitely determined to be the propagation phase delay in the supernatant liquid phase 73,
Expression (7) or a similar expression is obtained by using a combination of 6 or θ75, θ42 or θ31 determined to be the propagation phase delay in the sludge phase 72, and θ64 or θ53 determined to be the propagation phase delay passing through the sludge interface 74. H can be obtained based on the following equation.

Alternatively, as another method, when the components are predetermined to some extent, such as the supernatant liquid phase 73 and the sludge phase 72, the propagation phase delay in the supernatant liquid phase 73 and
The propagation phase delay in the sludge phase 72 is obtained in advance,
It is good to keep it on a table. Since the permittivity varies depending on the temperature, the respective propagation phase delays can be stored in the memory 49 in a table having a range having a certain width θa1 to θa2 and θb1 to θb2. Then, the measured propagation phase lag is in any of the ranges θa1 to θa.
If it does not belong to a2 and θb1 to θb2, it can be determined that the interface is between the two antennas switched at that time. Then, h can be obtained based on equation (7) or an equation similar thereto using θ86 or θ75 belonging to the range of θa1 to θa2 and θ42 or θ31 belonging to the range of θb1 to θb2.

Further, by arranging a set of antennas for transmitting and receiving at a distance of L which is 1/2 of the propagation distance 2L,
For example, the sludge interface 74 is the transmitting / receiving antenna 14-6 or 1
4-4, the value of θ46 is θ86 or θ4
In the case where it becomes difficult to determine whether or not the sludge interface 74 exists between the transmitting and receiving antennas 14-6 and 14-4, for example, both sides of the transmitting and receiving antenna 14-4 near the sludge interface 74 may be used. A certain transmitting / receiving antenna 14-5,
The values of the propagation phase delay θ53 between 14-3 are θ86, θ7
5, θ42 and θ31, so that θ53
Can be used to determine h.

Further, since each of the transmitting and receiving antennas can receive the signal with two transmitting and receiving antennas, for example, the signal is transmitted from the transmitting and receiving antenna 14-4 and transmitted and received.
If the attenuation is large when receiving at 4-2, the signal can be transmitted from the transmitting / receiving antenna 14-4 and the propagation phase delay can be measured using the received signal of the adjacent transmitting / receiving antenna 14-3. For example, the transmitting / receiving antenna 14-6
Using the propagation phase delay θ65 between the transmission / reception antenna 14-5 and the transmission / reception antenna 14-5, the propagation phase delay θ54 between the transmission / reception antenna 14-5 and the transmission / reception antenna 14-4, and the propagation phase delay θ43 between the transmission / reception antenna 14-4 and the transmission / reception antenna 14-3. hand,

[0038]

(Equation 8) H can also be obtained from the following equation.

In the case where the height of the general bottom surface 76a of the sludge sedimentation basin 70 is made coincident with the height of the transmitting / receiving antenna 14-2 as shown in the example of the figure, the general bottom surface 7 is obtained from h obtained as described above.
6a the depth H of the sludge phase 72

[0040]

(Equation 9) Can be obtained from

When H becomes larger than the set value,
Sludge is drawn out from the sludge drawing port 78 to prevent the sludge from being discharged from the drain port 79. Since the extracted sludge is processed for reuse, it is managed so that H does not become too small so that the supernatant liquid is not mixed and extracted from the sludge extraction port 78.

Since the measurement is performed by using the microwave, the measurement can be performed even if there is a bubble, a granular substance, a suspended substance attached to the antenna, or the like. When bubbles are present, the dielectric constant is temporarily lowered, so that the obtained propagation phase delay is also temporarily reduced. However, the effects of the bubbles can be removed by performing continuous measurement. In the case of using ultrasonic waves, measurement becomes impossible if bubbles exist, but in this embodiment, it is possible to measure the propagation phase delay even if bubbles exist, so it is necessary to determine the presence or absence of bubbles. Can also.

When ultrasonic waves are used, if the interface is not clear, a reflected wave cannot be obtained and measurement becomes impossible. However, in this embodiment, when the concentration continuously changes and the interface is not clear, However, since the propagation phase delay can be measured, the interface can be obtained.

Further, since the antenna is largely attenuated in the liquid, it is hardly affected by reflection from nearby structural foreign matter.

Further, JP-A-10-142167,
As described in JP-A-10-142168, the density can be obtained from the propagation phase delay, and the density near the interface can also be obtained.

Next, FIG. 3 is a diagram showing a second embodiment of the present invention.

In the figure, a microwave interferometer 50 according to this embodiment has an antenna mounting pipe (mounting portion) 52 having a U-shaped portion at the lower end, and is mounted on the upper side of the U-shaped portion of the antenna mounting pipe 52. Upper transmitting antenna 54-1 and upper receiving antenna 54-2, and lower transmitting antenna 54-3 and lower receiving antenna 54-4 attached below the U-shaped portion of the antenna mounting pipe 52.
And a suspension wire 5 for suspending the antenna mounting pipe 52.
6, a lifting / lowering device 58 that lifts and lowers the antenna mounting pipe 52 by winding and unwinding the suspension wire 56, and a measuring device main body 60 having substantially the same configuration as the measuring device main body 16.

The upper transmitting antenna 54-1, the upper receiving antenna 54-2, the lower transmitting antenna 54-3, and the lower receiving antenna 54-4, which are arranged so as to form a quadrangle, respectively pass through the antenna mounting pipe 52. It is connected to the measuring instrument main body 60 by the inserted signal line. Upper transmitting antenna 5
The distance between 4-1 and the upper receiving antenna 54-2 and the distance between the lower transmitting antenna 54-3 and the lower receiving antenna 54-4 are set to the same distance L, respectively.
Upper transmitting antenna 54-1 and lower receiving antenna 54-4
Is preferably set to the same distance L. The upper transmitting antenna 54-1 includes a pair of antennas for transmitting microwaves to both the upper receiving antenna 54-2 and the lower receiving antenna 54-4, and the lower receiving antenna 54-4 is connected to the lower receiving antenna 54-4. It is composed of a pair of antennas that receive microwaves from both the transmitting antenna 54-3 and the upper transmitting antenna 54-1.

The operation of the microwave interface meter 50 configured as described above will be described.

The antenna mounting pipe 52 is lowered using the elevating device 58, the microwave is transmitted from the upper transmitting antenna 54-1 and the microwave is received by the upper receiving antenna 54-2. The propagation phase delay θa from 1 to the upper receiving antenna 54-2 is measured.
Further, the microwave is transmitted from the lower transmitting antenna 54-3, and the microwave is received by the lower receiving antenna 54-4, and the propagation phase delay θb from the lower transmitting antenna 54-3 to the lower receiving antenna 54-4. Is measured. When the difference between θa and θb is small and smaller than a certain threshold value θT, the upper antennas 54-1 and 54-2 and the lower antennas 54-3 and 54-5
Supernatant liquid phase 7 in which all antennas 4-4 are in the same phase
3, the measuring instrument main body 60 displays an indication to that effect, and automatically or manually operates the elevating device 58 to lower the antenna mounting pipe 52 further downward.

When the sludge interface 74 is positioned between the upper antennas 54-1 and 54-2 and the lower antennas 54-3 and 54-4, the propagation phase delay θa and the propagation phase delay θ
The difference from b should be large. Therefore, θa and θb
Is larger than the threshold θT, the sludge interface 7
4 is an upper transmitting antenna 54-1 and a lower receiving antenna 54
-4, the microwave is transmitted from the upper transmitting antenna 54-1 and received by the lower receiving antenna 54-4, and the propagation phase delay θab is measured.

From the lower receiving antenna 54-4 to the sludge interface 7
4 as h, these propagation phase delays θ
a, θb, and θab are represented by the following equations, respectively.

[0053]

(Equation 10) Εa and εb are eliminated from the equations (7), (8) and (9), and h
And ask for

[0054]

[Equation 11] And the interface position h can be calculated from the phase delays θab, θa, θb. Suspended suspension wire 5
Since the distance S between the top of the suspension wire 56 and the upper transmitting antenna 54-1 can be known from the length of 6, the distance between the top of the suspension wire 56 and the general bottom surface 76a of the sludge sedimentation basin 70 is known. Using the distance D, the sludge phase 72 on the general bottom surface 76a
The depth H of

[0055]

(Equation 12) And the same effect as in the first embodiment can be obtained. Further, in this embodiment, instead of providing the elevating device, it can be configured with a small number of antennas.

[0056]

As described above, according to the first to sixth aspects of the present invention, since measurement is performed using microwaves, bubbles, granular substances, suspended substances adhered to an antenna, etc. Even if there is, the measurement can be performed, and even when the concentration is continuously changed and the interface is not clear, the measurement of the propagation phase delay can be performed, so that the interface can be obtained.

Further, since the antenna is largely attenuated in the liquid, it is hardly affected by reflection from nearby structural foreign matter, and there is no restriction on the installation place of the antenna.

[Brief description of the drawings]

FIG. 1 is an explanatory block diagram illustrating a first embodiment of the present invention.

FIG. 2 is a block diagram of the measuring instrument main body of FIG. 1;

FIG. 3 is an explanatory block diagram showing a second embodiment of the present invention.

FIG. 4 is an explanatory block diagram of a conventional interface measurement meter using ultrasonic waves.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Microwave interface meter 12 Antenna attachment pipe (attachment part) 14-1, 14-2, 14-3, ... 14-8 Transmission / reception antenna 16 Measuring instrument main body 50 Microwave interface meter 52 Antenna attachment pipe (attachment part) 54- 1,54-2,54-3,54-4 Transmitting / receiving antenna 56 Suspension wire 58 Elevating device 60 Measuring instrument body

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 16, 1999 (1999.6.1
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

Further, since the microwave is greatly attenuated in the liquid, it is hardly affected by reflection from a nearby structural foreign matter.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction contents]

Further, since the microwave is greatly attenuated in the liquid, it is hardly affected by reflection from nearby structural foreign matter, and there is no restriction on the installation location of the antenna.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (6)

[Claims] 1. An interface measuring method for detecting an interface position between a first phase and a second phase having different dielectric constants, wherein the two antennas are both in the first phase and have a known distance from each other. And propagate the microwave between two antennas that are both in the second phase and have a known distance from each other to measure the propagation phase delay. A microwave is propagated between two antennas in the first phase and the second phase, which are located in the first phase and the second phase with the interface therebetween, and the propagation phase delay is measured. An interface measurement method characterized by obtaining an interface position. 2. An interface meter for detecting an interface position between a first phase and a second phase having different dielectric constants, comprising two antennas both in the first phase and having a known distance from each other. A first set of antennas for propagating microwaves from one antenna to the other antenna, and two antennas, both in the second phase and having a known distance from each other, from one antenna to the other. A second antenna set for propagating waves, and two antennas positioned in the first phase and the second phase with the interface therebetween and having a known distance from each other, from one antenna to the other antenna A microwave interface meter including a third set of antennas for propagating microwaves, and a measuring instrument body for obtaining a propagation phase delay of each antenna set and obtaining an interface position from these propagation phase delays. 3. The first to third antenna sets each include two antennas appropriately selected from a plurality of antennas mounted at predetermined intervals on a mounting portion extending substantially perpendicular to an interface. The microwave interface meter according to claim 2, comprising: 4. The mounting method according to claim 1, wherein every other antenna is mounted in the same direction with respect to the axis of the mounting portion, and adjacent antennas are mounted at positions facing each other with respect to the axis of the mounting portion. Item 3. The microwave interface meter according to Item 3. 5. The first to third antenna sets are each arranged in a quadrangular shape by a mounting portion.
3. The microwave interferometer according to claim 2, comprising two antennas selected from the one antenna. 6. The microwave interferometer according to claim 3, further comprising an elevating device for elevating and lowering the mounting portion.