KR101195438B1 - Ultrasonic flowmeter and method of measuring flux by ultrasonic waves - Google Patents

Abstract

The present invention relates to an ultrasonic flowmeter and an ultrasonic flow rate measuring method capable of accurately measuring a flow rate of a fluid flowing in a state in which a fluid is not completely filled in an oil pipe, that is, an obesity pipe. The ultrasonic flowmeter according to the present invention includes an oil pipe and a pair of ultrasonic vibrators installed on the oil pipe so as to face each other on the upstream side and the downstream side in the flow direction of the fluid, and are spaced apart from each other along the direction crossing the flow direction of the fluid. And a plurality of ultrasonic flow rate measuring lines arranged side by side, and installed in the conduit to transmit ultrasonic waves upwards, and the ultrasonic waves proceed upward through the fluid and are reflected from the surface of the fluid, It is electrically connected to the receiving ultrasonic sensor, the ultrasonic vibrator and the ultrasonic sensor, and measures the time required for the ultrasonic wave to be transmitted between the pair of ultrasonic vibrators on the ultrasonic flow rate measurement line, and uses the time to measure the flow velocity of the fluid. From the point at which the ultrasonic wave is sent by the ultrasonic sensor, after the ultrasonic wave is reflected off the surface of the fluid It includes a controller for measuring the time required to receive from the wave sensor, using the time to measure the level of the fluid, and calculates the flow rate of the fluid using the measured flow rate and level.

Ultrasonic Oscillator, Ultrasonic Sensor, Flow Rate, Flow Rate, Water Level, Obesity Tube

Description

Ultrasonic flowmeter and method of measuring flux by ultrasonic waves

The present invention relates to an apparatus and a method for measuring the flow rate of a fluid using ultrasonic waves, and more particularly, an ultrasonic flowmeter for measuring the flow rate of a fluid flowing in an obese tube state, that is, a state in which the fluid is not filled inside the duct. And an ultrasonic flow rate measuring method.

In order to measure the flow rate of the fluid flowing in the state in which the fluid is not filled inside the tube, that is, the obesity tube state, the flow rate of the fluid and the level of the fluid should be measured. In the conventional case, the flow rate of the fluid was measured using an obesity tube flow meter of the type shown in FIG.

Referring to FIG. 1, the conventional obesity tube flow meter 9 is formed by combining an ultrasonic flowmeter 1 and a sound wave level meter 4.

The ultrasonic flowmeter 1 includes an oil pipe 2 and an ultrasonic flow rate measuring line. The oil pipe 2 is formed in a hollow shape, and fluid flows inside. The ultrasonic flow rate measuring line is provided in plurality, and is spaced apart from each other in the vertical direction and installed in the oil pipe side by side. Each ultrasonic flow rate measurement line consists of a pair of ultrasonic vibrators 3 facing each other.

The sound level gauge 4 is for measuring the level of the fluid in the oil pipe 2, and includes a waveguide 5, a sound wave transmitter 6, and a sound wave receiver 7. The waveguide 5 is formed in a hollow shape and is coupled to the upper end of the oil pipe 2. The sound wave transmitter 6 is coupled to the waveguide 5 and transmits sound waves downwardly toward the surface of the fluid. The sound wave receiver 7 is disposed below the sound wave transmitter 6 and receives sound waves transmitted from the sound wave transmitter 6 and sound waves reflected from the surface of the fluid after being emitted from the sound wave transmitter 6.

In addition, the ultrasonic vibrator 3 of the ultrasonic flowmeter and the sound wave transmitter 6 and the sound wave receiver 7 of the sound wave level meter are connected to a controller (not shown). The controller measures the flow velocity of the fluid by using a so-called 'propagation time difference' method, which uses the difference in the time at which the ultrasonic wave is transmitted between the pair of ultrasonic vibrators 3 of each ultrasonic flow velocity measurement line. In addition, the controller measures the water level h of the fluid using the time taken for the sound wave transmitted from the sound wave transmitter 6 to reach the sound wave receiver 7 after being reflected from the surface of the fluid. The flow rate of the fluid flowing along the oil pipe 1 is calculated using the water level.

However, in the case of the conventional obesity tube flow meter 9, the frequency of the ultrasonic wave transmitted from the ultrasonic vibrator 3 is several hundred kilohertz, while the frequency of the acoustic wave transmitted from the acoustic wave transmitter 6 is several tens of kilohertz. The frequency bands of the two waves are different from each other. Therefore, the time required for transmitting and receiving ultrasonic waves between a pair of ultrasonic vibrators 3 using one controller, and the time required for transmitting and receiving sound waves between the sound wave transmitter 6 and the sound wave receiver 7 In the case of measuring time, an error occurs in the measured time. In other words, when measuring the transmission and reception times of two kinds of radio waves having different frequency bands with one controller, the accuracy is lowered. Therefore, an error occurs in the measured time required, so that the flow rate is measured incorrectly. There is a problem.

In addition, in the conventional case, the waveguide 5 having a predetermined length, that is, a length longer than the dead period of the sound wave receiver 6, must be separately provided in the canister 2. Here, the dead zone will be described with reference to FIG. 2.

The principle of measuring the water level by measuring the time difference between the sound wave passing through the sound wave receiver 7 and reflected from the surface of the fluid and passing back through the sound wave receiver 7 is shown in FIG. The sound wave transmitted downward from the sound wave receiver 6 begins to be received by the sound wave receiver 7 (a), and the sound wave reflected from the surface of the fluid is received again by the sound wave receiver 7 after the measurement point (b). If it starts (c), it uses the time difference between two time points (a, c) at which two sound waves are measured. However, as shown in FIG. 2 (B), the sound waves reflected from the surface of the fluid before the time point b 'at which the sound waves transmitted downward from the sound wave receiver 6 are terminated at the sound wave receiver 7 When received by the acoustic wave receiver 7, two sound waves are overlapped and measured as one sound wave, so that the time difference between two time points a 'and c' at which the two sound waves start to be measured cannot be measured. The phenomenon that can not be measured occurs. This phenomenon occurs because the distance between the surface of the sound wave receiver and the sound receiver is close, and the dead zone from the surface to the point where this phenomenon can occur is called.

That is, in the conventional case, in order to measure the water level, the waveguide 5 having a length greater than the dead period must be separately installed, and thus the size of the obesity pipe flowmeter 9 becomes large, and therefore, in the installation of the obesity pipe flowmeter 9 There is a problem that space limitation or difficulty occurs.

The present invention has been made to solve the above problems, an object of the present invention is to provide an ultrasonic flow meter and ultrasonic flow rate measuring method capable of accurately measuring the flow rate of the fluid flowing in the obesity tube state.

In order to achieve the above object, the ultrasonic flowmeter according to the present invention is installed in the conduit so as to face each other on the upstream side and the downstream side of the flow direction and the flow direction of the fluid and the ultrasonic wave to send and receive mutually And a pair of ultrasonic vibrators, each of which has a plurality of ultrasonic flow rate measuring lines disposed side by side and spaced apart from each other along a direction crossing the flow direction of the fluid, and installed in the conduit to transmit ultrasonic waves upwards. An ultrasonic sensor which is ultrasonically advanced upward through the fluid and is reflected from the surface of the fluid and receives ultrasonic waves downwardly, and is electrically connected to the ultrasonic vibrator and the ultrasonic sensor, wherein each ultrasonic flow velocity is measured Measure the time it takes for ultrasound to pass between a pair of ultrasonic vibrators on the line. Using this time, the flow velocity of the fluid is measured, and the time taken from the time when the ultrasonic wave is transmitted by the ultrasonic sensor to the time when the ultrasonic wave is reflected from the surface of the fluid and received by the ultrasonic sensor is measured. Measure the level of the fluid using the, characterized in that it comprises a controller for calculating the flow rate of the fluid using the measured flow rate and level.

The ultrasonic flow rate measuring method according to the present invention comprises a pair of ultrasonic vibrators disposed to face each other upstream and downstream of the flow direction of the fluid flowing along the conduit and each other in a direction crossing the flow direction of the fluid. In the ultrasonic flow rate measuring method for measuring the flow rate of the fluid by using a plurality of ultrasonic flow rate measuring lines provided in the flow pipe, the ultrasonic wave is upstream of the two ultrasonic vibrators of each ultrasonic flow rate measuring line The time required for receiving the ultrasonic wave transmitted by the upstream ultrasonic vibrator from the downstream ultrasonic vibrator from the time point at which it is transmitted, and the downstream ultrasonic wave in the upstream ultrasonic vibrator from the time when the ultrasonic wave is transmitted from the downstream ultrasonic vibrator. Until you receive the ultrasound from the vibrator Measuring the difference in the time taken, the main flow rate measuring step of measuring the flow rate of the fluid passing between the two ultrasonic vibrator, and the ultrasonic wave proceeds upward through the fluid from the time when the ultrasonic sensor sends the ultrasonic wave A water level measurement step of measuring the level of the fluid by measuring a time required until it is received by the ultrasonic sensor after being reflected from the surface of the fluid, and the flow velocity measured in the main flow rate measurement step, And a flow rate calculation step of calculating a flow rate of the fluid flowing along the duct using the level measured in the level measurement step.

According to the present invention having the above-described configuration, since both ultrasonic waves are used in the flow rate and level measurement process, an error occurs in the required time measured due to the difference in the frequency bands of the radio waves used in the flow rate and level measurement process as in the prior art. It is possible to accurately measure the flow rate of the fluid flowing in the obesity tube state.

In addition, since the size of the device is smaller, space limitations and difficulties in installing the device are reduced.

3 is a perspective view of an ultrasonic flowmeter according to an embodiment of the present invention, FIG. 4 is a schematic projection view of the projection line I of FIG. 3 as the flow direction a of the fluid, and FIG. 5 is V- of FIG. 3. It is sectional drawing of the V line.

3 to 5, the ultrasonic flowmeter 100 according to the present embodiment includes an oil pipe 10, an ultrasonic flow rate measuring line 21 to 25, an ultrasonic sensor 30, and a controller (not shown). Include.

"과 같은 형태, 예를 들어 하천이나 개수로 등이 될 수도 있다.Oil pipe 10 is formed in a hollow shape, the fluid flows therein. In the present embodiment, the oil pipe 10 is formed in a cylindrical shape having a radius of R in its cross section. However, the duct is not closed in cross-section, such as circular or square, "

It may be in the form of, for example, a river or a river.

및

만큼 이격된 지점에 각각 배치되며, 제4초음파 유속측정회선(24) 및 제5초음파 유속측정회선(25)은 제1초음파 유속측정회선(21)으로부터 상방으로

및

만큼 이격된 지점에 각각 배치된다. 각 초음파 유속측정회선(21~25)은 한 쌍의 초음파 진동자(21A~25B)를 포함하는데, 한 쌍의 초음파 진동자 중 하나의 초음파 진동자(21A,22A,23A,24A,25A)는 유체의 흐름방향(a) 상 상류측에 배치되며, 다른 하나의 초음파 진동자(21B,22B,23B,24B,25B)는 유체의 흐름방향(a) 상 하류측에 배치된다. 한 쌍의 초음파 진동자는 서로 마주보게 배치되며, 한 쌍의 초음파를 연결한 직선과 유체의 흐름방향은 일정각도(θ)를 이루게 된다. 후술하는 바와 같이, 각 초음파 진동자(21A~25B)는 컨트롤러(미도시)와 전기적으로 연결되며, 초음파를 수신 및 발신한다.Ultrasonic flow rate measuring lines 21 to 25 are provided in plural, and in this embodiment, five ultrasonic flow rate measuring lines 21 to 25 are provided. As shown in FIG. 4, of the five ultrasonic flow rate measuring lines 21 to 25, the first ultrasonic flow rate measuring line 21 is disposed on the center line of the projection plane, and the second ultrasonic flow rate measuring line 22 and the third line. The ultrasonic flow rate measurement line 23 moves downward from the first ultrasonic flow rate measurement line 21.

And

The fourth ultrasonic flow rate measurement line 24 and the fifth ultrasonic flow rate measurement line 25 are upwardly disposed from the first ultrasonic flow rate measurement line 21.

And

It is disposed at each spaced apart point. Each ultrasonic flow rate measurement line 21 to 25 includes a pair of ultrasonic vibrators 21A to 25B, and one of the ultrasonic vibrators 21A, 22A, 23A, 24A, and 25A is a fluid flow. The ultrasonic wave transducers 21B, 22B, 23B, 24B, and 25B are disposed upstream of the direction a and upstream of the fluid flow direction a. A pair of ultrasonic vibrators are disposed to face each other, the straight line connecting the pair of ultrasonic waves and the flow direction of the fluid to form a certain angle (θ). As will be described later, each of the ultrasonic vibrators 21A to 25B is electrically connected to a controller (not shown), and receives and transmits ultrasonic waves.

The ultrasonic sensor 30 is a known device capable of transmitting and receiving ultrasonic waves, and its operation principle and structure are the same as those of an ultrasonic vibrator. In the present embodiment, the ultrasonic sensor 30 transmits and receives ultrasonic waves in the same frequency range (hundreds of kilohertz) as the ultrasonic vibrators 21A to 25B described above. As shown in FIG. 5, the ultrasonic sensor 30 is installed at the bottom of the canal 10 to transmit ultrasonic waves in an upward direction, in particular, in a direction orthogonal to the surface of the fluid. And receives an ultrasonic wave traveling downward. The ultrasonic sensor 30 is electrically connected to the controller as described later.

The controller is electrically connected to the ultrasonic vibrators 21A to 25B and the ultrasonic sensor 30. The controller measures the flow rate of the fluid using the time required for the ultrasonic wave to be transmitted between the ultrasonic vibrators of the ultrasonic flow rate measuring lines 21 to 25, and the fluid flowing inside the oil pipe 10 based on the measured flow rates. Calculate the average flow velocity of. Then, the controller measures the time required for the ultrasonic wave transmitted from the ultrasonic sensor 30 to be reflected back to the ultrasonic sensor 30 after being reflected from the surface of the fluid, and using this time, the water level (h) Is calculated. In addition, the controller calculates the flow rate of the fluid flowing along the oil pipe 10 by using the calculated average flow velocity of the fluid and the fluid level h. Details of flow rate, water level, and flow rate measurement performed in the controller will be described in the ultrasonic flow rate measurement method.

6 is a schematic flowchart of an ultrasonic flow rate measuring method according to an exemplary embodiment of the present invention, FIG. 7 is a schematic view for explaining Snell's law, and FIG. 8 illustrates an end flow rate measuring step shown in FIG. 6. FIG. 9 is a graph for explaining the effect of measuring the flow rate using the ultrasonic flow rate measurement method, and FIG. 10 is a graph showing a case where the ultrasonic wave is received by the ultrasonic sensor without overlapping the ultrasonic wave. FIG. 11 is a graph for describing a method of measuring a time required when ultrasonic waves are received by an ultrasonic sensor in an overlapped state.

6 to 11, the ultrasonic flow rate measuring method M100 according to the present embodiment includes a first preparation step S10, a second preparation step S20, a main flow rate measurement step S30, and an end flow rate measurement step. (S40), the average flow rate calculation step (S50), the water level measurement step (S60) and the flow rate calculation step (S70).

In the first preparation step (S10), a plurality of ultrasonic flow rate measuring lines 21 to 25 are installed in the oil pipe 10. At this time, as shown in FIG. 3, the plurality of ultrasonic flow rate measuring lines 21 to 25 are installed to be spaced apart from each other in a direction crossing the flow direction a of the fluid, and a pair of ultrasonic vibrators of each ultrasonic flow rate measuring line are provided. Are installed on the upstream and downstream sides of each other. Thereafter, each of the ultrasonic vibrators 21A to 25b and the controller are electrically connected.

In the second preparation step (S20), as shown in FIG. 5, the ultrasonic sensor 30 is installed at the bottom of the milk pipe. At this time, the ultrasonic wave transmitted from the ultrasonic sensor 30 is installed in parallel with the ultrasonic transmitting surface of the ultrasonic sensor and the surface of the fluid so that the ultrasonic wave proceeds in a vertical direction with respect to the surface of the fluid. Thereafter, the installed ultrasonic sensor 30 and the controller are electrically connected.

On the other hand, the first preparation step (S10) and the second preparation step (S20) in the present embodiment by installing the ultrasonic flow rate measuring lines 21 to 25 and the ultrasonic sensor 30 directly in the oil pipe 10 as described above. However, as shown in FIG. 3, the first preparation step in the present embodiment may be performed by providing an oil pipe 10 in which the ultrasonic flow rate measuring lines 21 to 25 and the ultrasonic sensor 30 are installed. S10) and the second preparation step S20 may be performed.

In the main flow rate measuring step (S30), the flow rate of the fluid is measured using a so-called propagation time difference method while the fluid flows in the oil pipe 10. That is, the ultrasonic wave is generated in the upstream ultrasonic vibrator 21A of the first ultrasonic flow rate measuring line 21 and the ultrasonic wave 21A generated in the upstream ultrasonic vibrator 21B is received in the downstream ultrasonic vibrator 21B, but the upstream ultrasonic wave is received. The time T ₁₂ taken from the time when the ultrasonic wave is generated in the vibrator 21A until the downstream ultrasonic vibrator 21B receives the ultrasonic wave generated in the upstream ultrasonic vibrator 21A is measured. On the contrary, the ultrasonic wave is generated in the downstream ultrasonic vibrator 21B and the ultrasonic wave 21B in the downstream ultrasonic wave generator 21B receives the ultrasonic wave generated from the upstream ultrasonic vibrator 21B. the side ultrasonic transducer (21A), the time T ₂₁ it took until it receives the ultrasonic waves generated by counting the downstream-side ultrasonic transducer (21B) is measured. At this time, the ultrasonic vibrators of the other ultrasonic flow rate measurement lines except for the first ultrasonic flow rate measurement line 21 to be measured are not operated. If ultrasonic waves are also received by the ultrasonic vibrators other than the ultrasonic vibrators 21A and 21B of the first ultrasonic flow rate measurement line, the received signal indicating that the ultrasonic waves have also been received is transmitted to the controller. In addition, when a plurality of received signals are received together with the controller as described above, side effects occur and measurement results are inaccurate.

On the other hand, the sound velocity that the ultrasonic wave emitted from the ultrasonic vibrator propagates through the fluid under the condition that the fluid does not move is called C, and the flow velocity of the fluid passing through the straight line K1 connecting the two ultrasonic vibrators 21A and 21B. If V ₁ , and the distance between two ultrasonic vibrators 21A and 21B is L, T ₁₂ and T ₂₁ are as follows.

,

,

The time T _{12 when} the ultrasonic wave is fired in the forward direction with respect to the flow direction of the fluid is shorter than the time T ₂₁ when the ultrasonic wave is fired in the reverse direction with respect to the flow direction of the fluid. If we find the time difference ΔT,

항은 무시할 수 있을 정도로 작은 양이다. 따라서, 두 초음파 진동자(21A, 21B)를 연결한 직선(K1)상을 통과하는 유체의 유속 V₁은

이 된다. here

The term is negligibly small. Therefore, the flow rate V ₁ of the fluid passing through the straight line K1 connecting the two ultrasonic vibrators 21A and 21B is

.

In the same manner, the flow rates V ₂ to V ₅ of the fluid passing through the straight lines K2 to K5 are measured using the remaining ultrasonic flow rate measuring lines 22 to 25. In this case, in the case of the ultrasonic flow rate measurement line 25, that is, the fifth ultrasonic flow rate measurement line 25 in FIG. 4, the ultrasonic velocity measurement line is disposed outside the fluid. The difference does not occur. That is, the time required for transmitting the ultrasonic wave when transmitting the ultrasonic wave in the forward direction with respect to the flow direction of the fluid and the time required for transmitting in the reverse direction become ΔT = 0. Therefore, the flow rate of the fluid passing through this point becomes zero, and as will be described later, the flow rate V ₅ at this point is excluded in the process of obtaining the average flow rate of the fluid.

In the end velocity measurement step (S40), the ultrasonic flow velocity measurement line disposed at the lowermost side of the five ultrasonic flow velocity measurement lines 21 to 25, that is, the third ultrasonic flow velocity measurement line 23 and the point surrounded by the bottom surface of the tube, pass through. Measure the flow rate of the fluid. Hereinafter, the total reflection phenomenon used in the end velocity measurement step S40 will be described first, and then the process of the end velocity measurement step S40 will be described in detail.

Snell's law, which represents the relationship between the angle of incidence and the angle of refraction when light rays or radio waves enter and pass through the interface of different media, is expressed by the following equation.

C ₁ / C ₂ = sinθ ₁ / sinθ ₂ = n ₂ / n ₁

In this case, C ₁ and C ₂ are the speeds of propagation propagating through the medium 1 and the medium 2, θ ₁ and θ ₂ are the incident angle and the refractive angle, n ₁ and n ₂ are the refractive index of the medium 1 and medium 2.

According to Snell's law, the refractive index of the medium and the propagation speed of the propagation in the medium are inversely proportional to each other, and as shown in FIG. 7, the radio wave is incident from the medium having a small refractive index n ₁ to the medium having a large refractive index n ₂ . In this case, the reflection angle θ ₂ is larger than the incident angle θ ₁ . In addition, as the incident angle θ ₁ of the radio wave increases, the reflection angle θ ₂ also becomes larger and larger, and the incident angle at the instant when the reflection angle becomes 90 ° is referred to as the critical angle θ _c . When the incident angle θ ₁ is greater than or equal to the critical angle θ _c , total reflection occurs at the interface of the medium, and as shown by the dashed-dotted line in FIG. 6, radio waves are reflected at the same angle as the incident angle at the interface of the medium. When the critical angle (θ _c ) in which total reflection occurs is represented by the propagation speed of the propagation in the medium, θ _c = arcsin (C ₁ / C ₂ ). For example, the transmission speed of ultrasonic waves in the steel tube material of the present embodiment is about 5900m / s, and the ultrasonic transmission speed of the fluid flowing in the milk pipe, in particular water is about 1480m / s. Therefore, when ultrasonic waves are transmitted from the water to the steel direction, the critical angle θ _c becomes arcsin (1480/5900) ≒ 14.53 °.

On the other hand, the ultrasonic wave transmitted from the ultrasonic vibrator is not only propagated in the linear direction but is spread at a predetermined angle (direction angle) and propagates in the fluid. Therefore, as shown in FIG. 8, the ultrasonic waves transmitted from the upstream ultrasonic vibrator 23A of the third ultrasonic flow rate measurement line 23 also propagate toward the inner wall of the milk pipe, that is, the bottom surface, and the upstream ultrasonic vibrator 23A. ) And the ultrasonic wave incident to the central point of the downstream ultrasonic vibrator 23B, that is, the first reflection point H ₁ , are received by the downstream ultrasonic vibrator 23B after being reflected from the bottom surface of the milk pipe. For reference, in order for the ultrasonic wave to be totally reflected at the first reflection point H ₁ , the ultrasonic wave passes through the incident angle θ _i , that is, the first reflection point H ₁ , and is in contact with the first reflection point H ₁ . The first incident angle formed between the vertical straight line, that is, the diameter line T, and the straight line connecting the ultrasonic vibrator 23A and the first reflecting point H ₁ should be equal to or greater than the critical angle θ _c , that is, 14.53 °. do. When the first incident angle θ _i in the present embodiment is calculated using the geometry shown in FIG. 8, the first incident angle θ _i is arctan (5 ^0.5 ) ≒ 65.9 °. That is, since the first square θ _i of the ultrasonic waves is much larger than the critical angle θ _c , it can be seen that the ultrasonic waves transmitted from the upstream ultrasonic vibrator 23A are totally reflected at the first reflection point H ₁ . Therefore, the ultrasonic waves transmitted from the upstream ultrasonic vibrator 23A are received by the downstream ultrasonic vibrator 23B while maintaining almost the same intensity.

On the contrary, the ultrasonic wave transmitted from the downstream ultrasonic vibrator 23B of the third ultrasonic flow rate measurement line 23 also propagates toward the bottom surface of the milk pipe, wherein the upstream ultrasonic vibrator 23A and the downstream ultrasonic vibrator 23B The ultrasonic wave incident to the center point, that is, the second reflection point H ₂ , is reflected by the bottom surface of the milk pipe and then received by the upstream ultrasonic vibrator 23A. As shown in FIG. 8, since the first reflection point H ₁ and the second reflection point H ₂ coincide with each other, the second incidence angle is the same as the first incidence angle, and thus, in the downstream ultrasonic vibrator 23B. The transmitted ultrasound is also totally reflected at the second reflection point (H ₂ ).

That is, the ultrasonic wave transmitted from the third ultrasonic flow rate measurement line 23 is totally reflected at the bottom surface of the duct, and the process of the end velocity measurement step S40 will be described based on this.

First, when the ultrasonic wave is transmitted from the ultrasonic wave oscillator 23A upstream of the third ultrasonic flow rate measurement line 23, the ultrasonic wave propagates at a predetermined direction angle and is totally reflected at the first reflection point H ₁ and then the third ultrasonic wave. It is received by the ultrasonic vibrator 23B downstream of the flow rate measuring line. At this time, the first time required from the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator 23A until the ultrasonic wave is reflected at the _first reflecting point H ₁ and received by the downstream ultrasonic vibrator 23B. Measure On the contrary, when the ultrasonic wave is transmitted from the downstream ultrasonic vibrator 23B, the ultrasonic wave is reflected at the second reflection point H ₂ and then received by the upstream ultrasonic vibrator 23A, where the downstream ultrasonic vibrator 23B is received. From the time point at which the ultrasonic waves are transmitted, the second time required for the ultrasonic waves to be reflected by the second reflection point H ₂ and received by the upstream ultrasonic vibrator 23A is measured. Subsequently, by using the difference between the first time required and the second time required and the propagation time difference method described above, the flow rate V ₆ of the fluid passing on the path G through which the ultrasonic waves proceed can be obtained. However, as shown in FIG. 8, the ultrasonic wave proceeds while traversing the region surrounded by the third ultrasonic flow rate measurement line 23 and the bottom surface of the duct in which the ultrasonic wave is reflected, that is, the bottom layer region P of the duct shown by hatching. Therefore, the ultrasonic waves are evenly affected by the fluid passing through the region P. Therefore, the flow velocity of the fluid passing on the traveling path G of the ultrasonic wave may be set to the flow rate of the fluid passing through the bottom layer region P of the oil pipe.

In particular, in the case of the bottom layer region P, as shown in FIG. 9, since the change of the flow velocity is very severe by friction with the bottom surface of the milk pipe, it is necessary to be measured in order to calculate an accurate average flow speed in the milk pipe. However, it was not easy to provide an ultrasonic flow rate measurement line, so it was difficult to measure the flow rate by the conventional method. However, in the present embodiment, it is possible to measure the flow rate of the bottom layer region P by using ultrasonic waves totally reflected from the bottom surface of the milk pipe, and as a result, it is possible to measure the average flow velocity more accurately than in the prior art.

인 지점을 지나는 직선(K₆) 상을 통과하는 유체의 유속으로 설정한다. 다만, 설정되는 위치는 유관의 형상 또는 유관 바닥면의 마찰에 의한 영향 등에 따라서 달라질 수 있는 것으로서, 그 위치는 실험을 통하여 최적화된 지점으로 변경될 수 있을 것이다.Meanwhile, the flow velocity V ₆ measured in the end velocity measurement step S40 is included in the bottom layer region P of the oil pipe and passes through a straight line K ₆ parallel to the third ultrasonic flow velocity measurement line 23. Set to flow rate. In particular, in the present embodiment, the flow velocity V ₆ measured in the end velocity measurement step S40 is parallel to the third ultrasonic flow velocity measurement line 23, and the center of the bottom layer region P, that is, the height, is increased.

It is set to the flow rate of the fluid passing on the straight line K ₆ passing through the phosphorus point. However, the position to be set may vary depending on the shape of the tube or the effect of friction of the bottom surface of the tube, and the position may be changed to an optimized point through the experiment.

In the average flow rate calculation step (S50), the average flow rate (V) of the fluid using the _five flow rates V ₁ to V ₅ measured in the main flow rate measurement step (S30) and the flow rate V ₆ obtained in the end flow rate measurement step (S40). ) However, when the fluid is not filled at the point where the fifth ultrasonic flow rate measuring line 25 is arranged as in the present embodiment, the flow rate at this point should be excluded. The average flow velocity V of the fluid flowing in the oil pipe 10 is obtained by using the remaining flow rates excluding the flow rate V ₅ , that is, five flow rates V ₁ to V ₄ and V ₅ shown in the graph of FIG. 9. That is, in the average flow rate calculation step (S50), multiply each of the _five flow rates (V ₁ to V ₄ , V ₅ ) by weighting factors, add them up, and divide the sum by 5 to average the flow rate of the fluid flowing inside the pipe. Find (V).

The multiplication by multiplying the weighting factor is called the weighting factor method, which is a known method. The weighting factor depends on the arrangement of the ultrasonic vibrators placed in the canal, which can be determined by taking into account the repeated shape or the geometric shape of the canal cross section. As a known arrangement of the ultrasonic vibrators and a weighting factor accordingly, weighting factors such as a "Gaussian" shape, a "Shevysef" shape, and a "Taylor" shape are known and the description thereof will be omitted.

In the water level measurement step S60, the water level h of the fluid is measured. That is, in the water level measurement step S60, the time required for the ultrasonic wave to be received again after being reflected from the surface of the fluid from the time point at which the ultrasonic sensor 30 is transmitted is measured. Measure the water level.

As shown in an enlarged view in FIG. 5, some of the ultrasonic waves transmitted from the ultrasonic sensors are reflected at the interface between the duct 10 and the fluid, that is, the inner wall of the duct 10 and received by the ultrasonic sensor 30 again. Proceed upward through the fluid. The ultrasonic waves traveling upwards are reflected on the surface of the fluid and then moved downwards, and then received by the ultrasonic sensor 30 (in this case, a portion of the ultrasonic waves traveling downwards is reflected from the inner wall of the milk canal). Accordingly, the ultrasonic sensor is received by the ultrasonic sensor in the form of FIG. 10, and the time required from the time when the ultrasonic wave is transmitted to the ultrasonic sensor after the ultrasonic wave is reflected from the surface of the fluid can be measured. From the measured time (T _t) ultrasonic waves are subtracted time (T _e) it takes to pass through the oil pipe (10), becomes ultrasound is calculated time (T _t) required to proceed to the fluid, in this time After multiplying the speed of the ultrasonic waves in the fluid, dividing this value by 2 yields the fluid level h. In this case, the time (T _e ) for the ultrasonic wave to pass through the cannula 10 may be measured directly through the pulse shape received from the ultrasonic sensor, but the thickness of the canister 10 is the same material as that of the canister 10 and the corresponding material. It can also be obtained by dividing by the traveling speed of the ultrasonic wave at the temperature, wherein the temperature is set to the same temperature as the fluid.

On the other hand, when the fluid level is low, the ultrasonic waves reflected from the inner wall of the canal 10 and the ultrasonic waves reflected from the surface of the fluid overlap, so that ultrasonic waves are received in the form of FIG. In this case, since it is difficult to determine the reception time of the ultrasonic waves reflected from the surface of the fluid, the time required for the ultrasonic waves to proceed in the fluid is calculated in the following two manners rather than the method described above.

In the first method, two received ultrasounds are subjected to A / D conversion to generate a waveform in which a floor portion, that is, a peak portion, of two ultrasounds is connected, that is, a waveform of the shape shown in FIG. Then, the time (T _t ') between the two highest floors in the generated wave is defined as the time it takes for the ultrasonic wave to progress in the fluid, multiplying the traveling speed of the ultrasonic wave by 2 and dividing it by 2 (h) is calculated.

In the second method, new pulses are generated when the magnitude of the pulse in the two received ultrasounds is detected as a reference value, that is, a pulse higher than or equal to the reference line j shown in FIG. 11A, and FIG. 11C. Generate a waveform of the form shown in. At this time, the size of the reference value is preferably set to a size such that the number of times that the pulse is more than the reference value is detected in each of the two ultrasonic waves when the two ultrasonic waves are not overlapped. When the waveform of this type is generated, the generated wave is divided into two groups before and after the time when the two ultrasonic waves are overlapped, as shown in FIG. The time T _t '' is defined as the time it takes for the ultrasonic wave to progress in the fluid, and multiplying this time by the advancing speed of the ultrasonic wave and dividing by 2 yields the fluid level h.

In the flow rate calculation step (S70), the flow rate of the fluid is calculated by using the average flow rate and the water level previously obtained. That is, using the cross-sectional shape of the oil pipe 10 and the water level h of the fluid, the flow area X of the fluid flowing in the oil pipe 10, that is, the area of the hatched portion X of FIG. Multiplying the flow area (X) by the average flow rate yields the flow rate of the fluid.

As described above, in the present embodiment, the flow rate of the fluid and the water level are measured using the ultrasonic vibrators 21A to 25B and the ultrasonic sensor 30 having the same frequency band. Therefore, the measurement error is prevented from occurring in the controller due to the frequency difference of the radio waves (ultrasound and sound waves) used as in the prior art, and as a result, it is possible to accurately measure the flow rate of the fluid.

In addition, since a separate waveguide for level measurement is not required as in the prior art, an ultrasonic flowmeter can be manufactured in a smaller size than the conventional one, and thus space limitation and effort in installing the ultrasonic flowmeter are reduced.

In addition, in the present embodiment, since the flow rate of the fluid flowing through the bottom layer region of the milk pipe is reflected using the ultrasonic waves totally reflected from the bottom surface of the milk pipe and reflects it in the average flow speed of the fluid, the average flow speed of the fluid is measured more accurately, and thus the fluid The flow rate of can be measured more accurately.

On the other hand, as shown in phantom in Figure 6, the ultrasonic flow rate measuring method (M100) may further comprise a surface layer flow rate measuring step (S45). Surface layer flow rate measurement step (S45) is for measuring the flow rate around the surface of the fluid, the principle is the same as the above-described end flow rate measurement step (S40). In the surface layer flow rate measuring step (S45), an ultrasonic flow rate measuring line disposed below the surface of the fluid and disposed closest to the surface of the fluid is used, and using the water level (h) obtained in the above-described water level measuring step, As described in the flow rate measurement step, it is possible to determine which ultrasonic flow rate measurement line is to be used in the surface layer flow rate measurement step (S45) by using the time difference ΔT = 0 between the upward direction and the reverse direction in the ultrasonic flow rate measurement line where the fluid does not flow. . Hereinafter, with reference to the accompanying Figure 12, the surface layer flow rate measurement step (S45) will be described in detail.

Referring to FIG. 12, the ultrasonic waves transmitted from the upstream ultrasonic vibrator 24A of the fourth ultrasonic flow rate measurement line 24 are propagated at a predetermined direction angle and reflected from the surface of the fluid, and then the downstream ultrasonic vibrator 24B. The ultrasonic wave transmitted from the downstream ultrasonic vibrator 24B is also received by the upstream ultrasonic vibrator 24A after being reflected from the surface of the fluid. At this time, from the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator 24A, the time required until the ultrasonic wave is reflected from the surface of the fluid and received by the downstream ultrasonic vibrator 24B, and in the downstream ultrasonic vibrator 24B. From the time when the ultrasonic wave is transmitted, the time required for the ultrasonic wave to be reflected by the surface of the fluid and received by the upstream ultrasonic vibrator 24A is measured. In addition, if the propagation time difference method is used on the basis of the measured difference between the two times and the length of the path E through which the ultrasound proceeds, the flow velocity of the fluid passing through the path E through which the ultrasound proceeds can be obtained. At this time, the length of the path (E) through which the ultrasonic wave can be calculated using the above-mentioned fluid level (h) of the fluid and the geometry of the canal (10) (Pythagorean Theorem).

The ultrasonic wave proceeds across the surface layer region of the duct, i.e., the region surrounded by the surface of the fluid and the fourth ultrasonic flow velocity measurement line 24, and thus is evenly affected by the fluid passing through the surface layer region. Therefore, the flow velocity of the fluid passing on the traveling path E of the ultrasonic wave can be set to the flow rate of the fluid passing through the surface layer region of the oil pipe. In this way, if the average flow rate is calculated by reflecting the flow rate of the fluid passing through the surface layer region of the pipe in the average flow rate calculation step, the average flow rate of the fluid can be calculated more accurately, and as a result, the flow rate of the fluid can be obtained more accurately. It becomes possible.

Meanwhile, the water level measuring step may be performed in the following manner without using the ultrasonic sensor as described above. 13 is a view for explaining a water level measuring step according to another embodiment of the present invention. Hereinafter, the water level measuring step according to the present embodiment will be described with reference to FIG. 13.

First, among the plurality of ultrasonic flow rate measurement lines installed in the conduit, the ultrasonic flow rate measurement line, which is disposed below the surface of the fluid, is determined closest to the surface of the fluid. This can be determined using the fact that the time difference ΔT = 0 between the ultrasonic waves is transmitted.

Ultrasonic waves transmitted from the upstream ultrasonic vibrator 2A of the determined ultrasonic flow rate measurement line are received by the downstream ultrasonic vibrator 24B after being propagated at a predetermined direction angle and being reflected from the surface of the fluid, on the contrary, the downstream ultrasonic vibrator Ultrasonic waves transmitted from 24B are also reflected by the surface of the fluid and then received by the upstream ultrasonic vibrator 24A. At this time, the time T _r1 and the downstream ultrasonic vibrator from the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator 24A until the ultrasonic wave is reflected from the surface of the fluid and are received by the downstream ultrasonic vibrator 24B. The time T _r2 from the time when the ultrasonic wave is transmitted at 24B until the ultrasonic wave is reflected from the surface of the fluid and received by the upstream ultrasonic vibrator 24A is measured.

On the other hand, the flow velocity in the direction of the fluid from the upstream ultrasonic vibrator to the downstream ultrasonic vibrator is V, the velocity of the ultrasonic wave in the fluid is C, and the length of the path E 'through which the ultrasonic wave proceeds is L. ',

T _r1 = L '/ (C + Vcosθ) and T _r2 = L' / (C-Vcosθ).

Therefore, 1 / T _r1 + 1 / T _r2 = 2C / L ', and L _r can be known since T _r1 and T _r2 are measured values.

Since the distance 2L between the two ultrasonic vibrators 24A and 24B is known in advance, the distance (h ') from the ultrasonic velocity measurement line to the surface can be calculated using the geometry shown in FIG. Therefore, the fluid level can be known.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

For example, in the above-described embodiment, the ultrasonic sensor is configured to be installed on the outer wall of the milk pipe, but an insertion hole may be formed at the bottom of the milk pipe and the ultrasonic sensor may be inserted into the insertion hole. In this case, since the ultrasonic wave transmitted from the ultrasonic sensor proceeds directly through the fluid, as described above, there is an advantage in that the phenomenon that the ultrasonic wave is received after the portion of the ultrasonic wave is reflected from the inner wall of the milk canal is prevented.

In addition, the ultrasonic wave received from the upstream ultrasonic vibrator immediately after being transmitted from the upstream ultrasonic vibrator in the surface layer flow velocity measuring step and the end velocity measuring step, and reflected from the surface of the fluid or the bottom surface of the oil pipe after being emitted from the ultrasonic vibrator downstream The reflected waves received by the side ultrasonic vibrator may overlap each other. In this case, the difference in the time required for the two waves to be reached may be obtained by using the same two methods as in the above-described water level measurement step.

1 is a schematic cross-sectional view of a conventional obesity tube flow meter.

2 is a diagram for explaining a dead period.

3 is a perspective view of an ultrasonic flowmeter according to an embodiment of the present invention.

4 is a schematic projection of the projection line of FIG. 3 as viewed in the flow direction of the fluid.

5 is a cross-sectional view taken along the line VV of FIG. 3.

6 is a schematic flowchart of an ultrasonic flow rate measuring method according to an exemplary embodiment of the present invention.

7 is a schematic diagram for explaining Snell's law.

FIG. 8 is a projection view for explaining the end velocity measurement step shown in FIG. 6.

9 is a graph for explaining the effect of measuring the flow rate using the ultrasonic flow rate measurement method.

10 is a graph illustrating a case where ultrasonic waves are received by an ultrasonic sensor without overlapping.

FIG. 11 is a graph for describing a method of measuring a time required when ultrasonic waves are received by an ultrasonic sensor in an overlapped state.

12 is a cross-sectional view for explaining a surface layer flow rate measuring step.

13 is a cross-sectional view for explaining a water level measuring step according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100 ... Ultrasonic flow meter 10 ... Oil pipe

21 ~ 25 ... Ultrasonic flow rate measurement line 21A ~ 25B ... Ultrasonic oscillator

30 ... Ultrasonic sensor M100 ... Ultrasonic flow measurement method

S10 ... Step 1 Preparation S20 ... Step 2 Preparation

S30 ... Main flow rate measurement step S40 ... Step flow rate measurement step

S50 ... Average velocity calculation step S60 ... Level measurement step

S70 ... flow calculation stage

Claims (10)

An oil pipe through which fluid flows; A pair of ultrasonic vibrators installed on the conduit so as to face each other on the upstream side and the downstream side in the flow direction of the fluid, each having a pair of ultrasonic vibrators for transmitting and receiving ultrasonic waves therebetween, and in a direction intersecting with the flow direction of the fluid. A plurality of ultrasonic flow rate measuring lines spaced apart from each other; An ultrasonic sensor installed in the canal and transmitting ultrasonic waves upwardly, the ultrasonic waves traveling upward through the fluid and being reflected from the surface of the fluid and receiving ultrasonic waves downwardly; And It is electrically connected to the ultrasonic vibrator and the ultrasonic sensor, and measures the time required for the ultrasonic wave to be transmitted between the pair of ultrasonic vibrators of each ultrasonic flow rate measurement line, and uses the time to measure the flow velocity of the fluid, Measuring the time taken from the time when the ultrasonic wave is sent from the ultrasonic sensor to the time when the ultrasonic wave is reflected from the surface of the fluid and received by the ultrasonic sensor, and using this time to measure the level of the fluid, the measurement And a controller configured to calculate the flow rate of the fluid using the flow rate and the level. The controller comprising: From the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator among the two ultrasonic vibrators of each ultrasonic flow rate measurement line, the time required from the downstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the upstream ultrasonic vibrator, and the downstream side Measuring the difference in the time taken from the time when the ultrasonic wave is sent from the ultrasonic transducer to the upstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the downstream ultrasonic vibrator to measure the flow rate of the fluid passing between the two ultrasonic vibrators The main flow rate measurement step, The ultrasonic wave is reflected from the bottom surface of the milk pipe from the time point at which the ultrasonic wave is transmitted from the upstream ultrasonic vibrator of the pair of ultrasonic vibrators of the ultrasonic flow rate measuring line disposed at the lowermost side of the plurality of ultrasonic flow rate measuring lines. The difference between the time taken to be received by the vibrator and the time taken from the time when the ultrasonic wave is sent by the downstream ultrasonic vibrator until it is received by the upstream ultrasonic vibrator after being reflected from the bottom surface of the canal. An end velocity measurement step of measuring a flow velocity of the fluid passing through an area surrounded by the bottom surface of the ultrasonic pipe, in which the ultrasonic flow velocity measurement line disposed at the lowermost side and the ultrasonic wave are reflected; Water level measurement for measuring the level of the fluid flowing through the inside of the conduit, using the time it takes from the time the ultrasonic sensor is sent to the ultrasonic sensor after the ultrasonic wave is reflected from the surface of the fluid Perform the steps, Ultrasonic flow meter, characterized in that for calculating the flow rate of the fluid flowing in the flow pipe using the flow rate of the fluid measured in the main flow rate measuring step and the end flow rate measuring step, and the level of the fluid measured in the water level measuring step. The method of claim 1, The ultrasonic sensor is installed on the bottom of the tube so that the ultrasonic wave is transmitted in a direction orthogonal to the surface of the fluid. delete A plurality of ultrasonic transducers each provided on the upstream and downstream sides of the fluid flowing along the conduit so as to be spaced apart from each other in a direction crossing the flow direction of the fluid; In the ultrasonic flow rate measuring method for measuring the flow rate of the fluid using a flow rate measuring line, From the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator among the two ultrasonic vibrators of each ultrasonic flow rate measurement line, the time required from the downstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the upstream ultrasonic vibrator, and the downstream side Measuring the difference in the time taken from the time when the ultrasonic wave is transmitted from the ultrasonic wave oscillator to the ultrasonic wave transmitted from the downstream ultrasonic wave vibrator, the flow rate of the fluid passing between the two ultrasonic vibrators A main flow rate measuring step; From the time when the ultrasonic wave is sent from the ultrasonic sensor installed in the conduit, the ultrasonic wave proceeds upward through the fluid, is reflected from the surface of the fluid, and then moves downward to receive the ultrasonic sensor. A level measuring step of measuring the level of the fluid by measuring; And And a flow rate calculation step of calculating a flow rate of the fluid flowing along the oil pipe using the flow rate measured in the main flow rate measuring step and the water level measured in the water level measuring step. The ultrasonic wave is reflected from the bottom surface of the milk pipe from the time point at which the ultrasonic wave is transmitted from the upstream ultrasonic vibrator of the pair of ultrasonic vibrators of the ultrasonic flow rate measuring line disposed at the lowermost side of the plurality of ultrasonic flow rate measuring lines. The difference between the time taken to be received by the vibrator and the time taken from the time when the ultrasonic wave is sent by the downstream ultrasonic vibrator until it is received by the upstream ultrasonic vibrator after being reflected from the bottom surface of the canal. And an end velocity measurement step of measuring a flow velocity of the fluid passing through an area surrounded by the bottom surface of the ultrasonic pipe with the ultrasonic wave velocity measurement line disposed at the lowermost side and measuring the ultrasonic wave. In the flow rate calculation step, the flow rate of the fluid flowing along the flow pipe using the flow rate measured in the main flow rate measurement step and the end flow rate measurement step, and the water level measured in the water level measurement step, characterized in that the ultrasonic wave Flow measurement method. delete 5. The method of claim 4, The ultrasonic wave is generated from the time point at which the ultrasonic wave is transmitted from an upstream ultrasonic vibrator of the pair of ultrasonic vibrators of the ultrasonic flow rate measurement line disposed adjacent to the surface of the fluid below the surface of the fluid among the plurality of ultrasonic flow rate measurement lines. The time required to be reflected on the surface of the fluid and received by the downstream ultrasonic vibrator, and from the time when the ultrasonic wave is transmitted from the downstream ultrasonic vibrator, is reflected from the surface of the fluid and then reflected on the upstream ultrasonic vibrator. And a surface layer flow rate measuring step of measuring a difference in time taken until received, and measuring a flow rate of the fluid passing through the area surrounded by the ultrasonic flow rate measurement line and the surface of the fluid. In the flow rate calculation step, the flow rate of the fluid flowing along the flow pipe using the flow rate measured in the main flow rate measurement step and the surface layer flow rate measurement step, and the water level measured in the water level measurement step, characterized in that the ultrasonic wave Flow measurement method. A plurality of ultrasonic transducers each provided on the upstream and downstream sides of the fluid flowing along the conduit so as to be spaced apart from each other in a direction crossing the flow direction of the fluid; In the ultrasonic flow rate measuring method for measuring the flow rate of the fluid using a flow rate measuring line, From the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator of the two ultrasonic vibrators of each ultrasonic flow rate measurement line, the time required from the downstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the upstream ultrasonic vibrator, and the downstream The difference in the time taken from the time when the ultrasonic wave is transmitted from the side ultrasonic vibrator to the reception of the ultrasonic wave transmitted from the downstream ultrasonic vibrator by the upstream ultrasonic vibrator is measured to determine the flow velocity of the fluid passing between the two ultrasonic vibrators. A main flow rate measuring step; The ultrasonic waves are generated when the ultrasonic waves are transmitted from an upstream ultrasonic vibrator of the pair of ultrasonic vibrators of the ultrasonic flow velocity measurement line disposed adjacent to the surface of the fluid below the surface of the fluid among the plurality of ultrasonic flow rate measurement lines. The time required to be reflected on the surface of the fluid and received by the downstream ultrasonic vibrator, and from the time when the ultrasonic wave is transmitted from the downstream ultrasonic vibrator, is reflected from the surface of the fluid and then reflected on the upstream ultrasonic vibrator. A level measurement step of measuring a time required for reception to calculate a distance traveled by the ultrasonic wave, and calculating a level of the fluid based on the calculated distance; And And a flow rate calculation step of calculating a flow rate of the fluid flowing along the conduit using the flow rate measured in the main flow rate measuring step and the water level measured in the water level measuring step. delete A plurality of ultrasonic transducers each provided on the upstream and downstream sides of the fluid flowing along the conduit so as to be spaced apart from each other in a direction crossing the flow direction of the fluid; In the ultrasonic flow rate measuring method for measuring the flow rate of the fluid using a flow rate measuring line, From the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator among the two ultrasonic vibrators of each ultrasonic flow rate measurement line, the time required from the downstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the upstream ultrasonic vibrator, and the downstream side Measuring the difference in the time taken from the time when the ultrasonic wave is transmitted from the ultrasonic wave oscillator to the ultrasonic wave transmitted from the downstream ultrasonic wave vibrator, the flow rate of the fluid passing between the two ultrasonic vibrators A main flow rate measuring step; From the time when the ultrasonic wave is sent from the ultrasonic sensor installed in the conduit, the ultrasonic wave proceeds upward through the fluid, is reflected from the surface of the fluid, and then moves downward to receive the ultrasonic sensor. A level measuring step of measuring the level of the fluid by measuring; And And a flow rate calculation step of calculating a flow rate of the fluid flowing along the oil pipe using the flow rate measured in the main flow rate measuring step and the water level measured in the water level measuring step. In the level measurement step, the ultrasonic wave emitted from the ultrasonic sensor is reflected from the surface of the fluid and then received again after being reflected from the inner wall of the canal after the ultrasonic wave is fired from the time Tt. Multiply the sound velocity in the fluid of the ultrasonic wave by subtracting the time (Te), and divide this value by 2 to calculate the water level, After the ultrasonic wave is emitted from the ultrasonic sensor, when the first ultrasonic pulse reflected from the inner wall of the milk pipe and received and the second ultrasonic pulse reflected from the surface of the fluid overlap each other, Multiply the sound velocity in the fluid of the ultrasonic wave by the time Tt 'between the two highest pulse values in the total pulses generated by the first and second ultrasonic pulses, then divide this value by 2 to divide the fluid. Ultrasonic flow measurement method, characterized in that for calculating the water level. A plurality of ultrasonic transducers each provided on the upstream and downstream sides of the fluid flowing along the conduit so as to be spaced apart from each other in a direction crossing the flow direction of the fluid; In the ultrasonic flow rate measuring method for measuring the flow rate of the fluid using a flow rate measuring line, From the time when the ultrasonic wave is transmitted from the upstream ultrasonic vibrator among the two ultrasonic vibrators of each ultrasonic flow rate measurement line, the time required from the downstream ultrasonic vibrator to receive the ultrasonic wave transmitted from the upstream ultrasonic vibrator, and the downstream side Measuring the difference in the time taken from the time when the ultrasonic wave is transmitted from the ultrasonic wave oscillator to the ultrasonic wave transmitted from the downstream ultrasonic wave vibrator, the flow rate of the fluid passing between the two ultrasonic vibrators A main flow rate measuring step; From the time when the ultrasonic wave is sent from the ultrasonic sensor installed in the conduit, the ultrasonic wave proceeds upward through the fluid, is reflected from the surface of the fluid, and then moves downward to receive the ultrasonic sensor. A level measuring step of measuring the level of the fluid by measuring; And And a flow rate calculation step of calculating a flow rate of the fluid flowing along the oil pipe using the flow rate measured in the main flow rate measuring step and the water level measured in the water level measuring step. In the level measurement step, the ultrasonic wave emitted from the ultrasonic sensor is reflected from the surface of the fluid and then received again after being reflected from the inner wall of the canal after the ultrasonic wave is fired from the time Tt. Multiply the sound velocity in the fluid of the ultrasonic wave by subtracting the time (Te), and divide this value by 2 to calculate the water level, After the ultrasonic wave is emitted from the ultrasonic sensor, when the first ultrasonic pulse reflected from the inner wall of the milk pipe and received and the second ultrasonic pulse reflected from the surface of the fluid overlap each other, Selecting pulses exceeding a predetermined reference value from all pulses generated by the first ultrasonic pulses and the second ultrasonic pulses, and selecting the selected pulses before and when the first ultrasonic pulses and the second ultrasonic pulses overlap each other. After dividing into two groups, multiplying the sound velocity in the fluid of the ultrasonic wave by the time Tt '' between the last pulses of the two groups, and dividing this value by 2 to calculate the fluid level. Ultrasonic flow measurement method characterized in that.

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