KR20000024565A - The method and apparatus of gauging oil in an oil tank by utilizing ultrasonic waves - Google Patents

Abstract

PURPOSE: A method and apparatus for measuring flow amount of oil storage tank using ultrasonic wave is provided to decrease an error by improving an accuracy of a measuring device. CONSTITUTION: A transmitting unit(1) transmits an ultrasonic wave to an object-measured body. A receiving unit(2) receives the ultrasonic wave reflected from the object-measured body. A temperature detecting unit(3) measures an atmosphere temperature. A control unit(4) receives a value received in the receiving unit(2) and a value measured in the temperature detecting unit(3), and computes a distance value between a measuring device and the object-measured body according to values of the receiving unit(2) and the temperature detecting unit(3). A control unit of a managing computer receives the distance value and displays a last value through an output unit.

Description

The method and apparatus of gauging oil in an oil tank by utilizing ultrasonic waves

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring flow rates of oil storage tanks using ultrasonic waves. The present invention relates to a flow rate measuring method and an apparatus of an oil storage tank using ultrasonic waves, which can reduce the error in measuring the flow rate by improving the precision of the measuring device using a statistical method.

In general, in order to measure the flow rate stored in a storage tank buried underground, such as a gas station, a person directly measures the flow rate using a simple measuring device such as a rope, ruler, or rod.

In the case of measuring the flow rate using the simple physical measuring device as described above, it is efficient when the storage tank is relatively small, but it is actually installed to store crude oil or crude oil imported from foreign countries in the refinery and the like. In the case of bulky storage tanks that require large capacity, such as oil storage tankers and oil tankers, there are difficulties in surveying, and even when surveying, many errors occur and accurate flow rates cannot be measured.

In the case of a tank for storing a large amount of liquid, such as a large amount of oil, even if a small error is accompanied by a huge economic loss, it is necessary to measure the exact flow rate from the perspective of inventory management. There was a problem in that it is not possible to supply the correct amount due to the occurrence of an error in the flow rate when oiling even in order to supply to the oil.

Due to the trouble of having to use a measuring device and error, a user can use the measuring device in a place and storage facility where it is not easy to measure the exact distance using a physical measuring tool. Automatic measuring devices have been developed that can calculate the volume by measuring.

As the automatic measuring device, a measuring device using a capacitance method, an encoder method, an ultrasonic method, or a radar method is used, and the radar method generates an error. Small measurement accuracy is high, but the production cost is high, there is a problem that it is difficult to commercialize, on the other hand, the capacitive method has a problem that the measurement precision is greatly reduced, because the production cost is much reduced, but the error is large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and detects that sound waves are reflected off the surface of a measurement medium using a measuring device that emits ultrasonic waves. The objective is to increase the measurement accuracy to the maximum by reducing errors in surveying by displaying them in a conventional manner.

In order to achieve the above object, in order to increase the efficiency of transmission and reception, a horn is manufactured in a parabolic form, and a transmitter and receiver having an ultrasonic sensor built into the horn and a temperature detector for detecting the atmospheric temperature in the storage tank; It is an object of the present invention to provide a flow rate measuring device for an oil storage tank using ultrasonic waves, which includes a control unit for processing and outputting the detected value by a signal processing technique and an arithmetic and statistical method.

1 is an overall configuration of the ultrasonic flow rate measuring apparatus according to the present invention

2 is a block diagram of a transmitter according to the present invention

3 is an arrangement diagram of the ultrasonic sensor for transmission according to the present invention.

4 is a block diagram of a receiver according to the present invention;

5 is a flowchart illustrating a distance detection method between a flow rate measuring device and a measurement target in a control unit according to the present invention.

6 is a cross-sectional view of a Horn according to the present invention.

Fig. 7 is a graph showing the variation of the time data when the ultrasonic wave reaches the subject under the present invention.

8 is a state diagram showing that the ultrasound is concentrated by the horn according to the present invention

Figure 9 is a state diagram showing a dispersion angle equipped with a horn according to the present invention

* Description of Signs of Main Parts of Drawings *

1. Transmitter 2. Receiver

3. Temperature detector 4. Control part

5. Sensor 6. Horn

7. Ultrasound 8. Subject

9. Storage tank 10. Sound source

Hereinafter, described in detail with reference to the accompanying drawings that are configured by an embodiment of the present invention will be described.

1 is an overall configuration of the ultrasonic flow rate measuring apparatus according to the present invention.

As shown, the transmitter 1 and the storage tank 9 which receive the ultrasonic wave 7 reflected by the target object 8 and emit the ultrasonic wave 7 to the object 8. The temperature detection unit 3 for measuring the temperature in the air and the value detected by the device allow the distance between the measuring device and the target object 8 to be calculated by a microcontroller using a signal processing technique and an arithmetic and statistical method. It consisted of the control part 4.

Sound waves emitted from the ultrasonic sensor 5 for transmission of the transmitter 1 are scattered due to the characteristics of the parabolic horn 6 formed in the transmitter 1 as shown in FIG. Focused on the area to be measured and having directivity, the energy of the ultrasonic wave 7 reached per unit area of the object 8 is maximized and diverged to the object 8, and the object 8 The reflected sound waves were concentrated and received by the parabolic horn 6 to the receiving ultrasonic sensor 5 of the receiver 2.

The temperature detector 3 detects the air temperature in the storage tank 9 and detects the thermal expansion rate of the oil according to the temperature. The air temperature in the storage tank 9 is transmitted to the control unit 4 so as to transmit ultrasonic waves ( It is used to calculate the speed of sound, which is the speed in the air of 7), and the oil's own temperature is transmitted to a management computer (not shown) to be used when calculating the volume of the flow rate stored in the storage tank 9. It was.

Each value detected by the receiver 2 and the temperature detector 3 is transmitted to the controller 4, and the apparatus and the device are controlled by a signal processing technique and an arithmetic and statistical method of the microcontroller as shown in FIG. The distance from the measuring body 8 is outputted, and the distance value is transmitted to the control unit (not shown) of the management computer so that the final value is displayed through the output unit. The exact value of the flow rate stored inside was obtained.

2 is a block diagram of a transmitter 1 according to the present invention.

The transmitting unit 1 is composed of a transmitting ultrasonic sensor 5 and a parabolic horn 6 to amplify a signal, which is permitted by the time recording processing circuit 13a, in the transmitting signal amplifying unit 12 to transmit the ultrasonic wave. Transmitted to the sensor 11, but a signal of 23KHz is generally allowed to be amplified into a signal of 24Vp-p to be transmitted to the sensor, which is a value that can be appropriately changed by various conditions, such as the capacity of the storage tank, It is not limited to an embodiment.

The sound wave emitted from the sensor 11 is directed by the parabolic horn 6 and is emitted to the measurement target object 8 so that the controller 4 transmits the time recording processing circuit 13a of the transmitter 1. By measuring the value of the time point at which the signal is allowed and the time point at which the signal is received by the ultrasonic sensor 20 of the receiver 2, the time required for the ultrasonic wave 7 to reach the object 8 is detected.

3 is an arrangement diagram of the ultrasonic sensor 11 for transmission according to the present invention.

Ultrasonic wave 7 is attenuated in air due to its characteristics, and its reach is shorter than that of liquids and solids. In the transmitter 1, the arrangement of the ultrasonic sensor 11 is shown to improve the transmission power of the ultrasonic wave 7. Arranged in the form of '+' and adopting the array source method to keep the distance between each sensor, but the arrangement is maintained by keeping the interval of about 29mm.

In the case of a measuring device that emits general ultrasonic waves, the output power is improved by driving one ultrasonic sensor at a high voltage. However, as shown above, the transmitting unit 1 uses the ultrasonic transmitting sensor 11 having a maximum measuring distance of 6 m. By adopting the array source method in which five ultrasonic transmitters are arranged in a '+' shape, the directivity and output are improved to reach the maximum measurement distance up to 20m.

4 is a block diagram of the receiver 2 according to the present invention.

The receiving unit 2 includes a receiving ultrasonic sensor 20 and a parabolic horn 6 so that the sound waves emitted from the transmitting unit 1 and reflected on the object 8 are parabolic in the receiving unit 2. Concentrated and received by the ultrasonic sensor 20 for receiving by the horn 6, the received signal should be converted into a digital signal in order to be recognized by the microcontroller of the controller 4, for this purpose, 21), the second 22, the third 23 amplify the signal about 100,000 times, and compared with the voltage generated by the reference voltage generator 24, the time when the received signal is larger The control unit 4 is inputted to the recording processing circuit 13b so that the control unit 4 receives the time when the transmission signal is applied from the time recording processing circuit 13a of the transmitting unit 1 and the time recording processing circuit 13b of the receiving unit 2. The ultrasonic wave 7 measures the value at the point of time at which the signal is received and the object under test 8 It was such that the detection time taken to not reach.

5 is a flowchart illustrating a distance detection method between the flow rate measuring device and the measurement target object 8 in the controller 4 according to the present invention.

The controller 4 measures the distance between the device and the measurement target 8 by measuring the signal received by the receiver 1 by the microcontroller using a signal processing technique and an arithmetic and statistical method. The accuracy of the measuring device is improved by almost no occurrence.

The process of measuring the distance between the apparatus and the object under test 8 by the controller 4 will now be described.

The transmitter 1 receives an ultrasound signal for a predetermined time from the time recording processing circuit 13a in the transmitting ultrasound sensor 11 arranged in an array source method and emits the ultrasound signal to the object 8 to be measured (100). 23KHz signal is allowed for 500 kHz, and when the sound wave emitted from the transmitter 1 is received by the receiver 2, it is reflected by another object that is not reflected by the object 8 to directly receive the receiver 2 Since a direct wave (not shown), which is a sound wave coming in), is first received, many errors occur when calculating the distance between the object 8 and the flow rate measuring device.

In order to solve this problem, the direct wave is not received during the time when the direct wave is received, so that the direct wave is not received and is a sound wave required for calculating the distance between the object 8 and the flow measurement device. Only the sound wave reflected by (8) is to be received by the receiver 2 (110), but the time to keep it from being received by the receiver 2 to remove the direct wave is generally about 1.2 ms.

The receiver 2 detects the time required for the ultrasonic wave 7 to reach the object 8 when the reflected wave reflected by the object 8 is received while the direct wave is excluded. (120).

As a device for detecting the time required for the ultrasonic wave 7 to reach the object 8, a transmitter having a 16-bit timer (not shown) having a resolution of 0.8 s is built into the microcontroller of the controller 4. The timer is initialized at the time point at which the signal is allowed in the time recording processing circuit 13a of (1), and the value of the timer is received at the time point at which the signal reflected by the measurement object 8 through the receiver 2 is received. Measurement was made.

As described above, the change width between the time data measured by the timer and the time data measured immediately before is measured (130), and as shown in FIG. However, assuming that the measured object 8 does not change by more than 3.0 mm in 150 ms, if the variation with the previously measured time data exceeds ± 5, that is, ± 40 ms, this value cannot be regarded as normal data and is ignored. (140), in this case, wait for a predetermined time until the afterimage of the ultrasound (7) is removed again to emit the ultrasound (7) in the transmission unit 1 to go through the above process, but of the ultrasound (7) Waiting time until afterimages were removed was usually about 150 ms.

In Fig. 7, the portion indicated as Error shows the case where the change range from the previous value is excluded in excess of the reference value.

If the rate of change from the previous value exceeds the reference value for one second to actively cope with the sudden change of the subject 8 in case the sudden change occurs in the storage tank 9, the error count is increased. If the error count exceeds 10, the value is set to a new reference value, and the error count is initialized (150).

The value assumed in the above process is set to a value based on the case of a large storage tank, so in the case of a small storage tank, the set value may be reset according to the storage tank of the corresponding capacity.

The time required for the ultrasonic wave to reach the subject 8 detected through the above process is stored in a memory (not shown) (160), and typically about 80 data are detected for a time of about 12 seconds. If the distribution of data is considered, the maximum and minimum values of about 20 data are excluded (170), and the remaining 40 data are averaged (180), so that the ultrasound can be stable and reliable. The time taken for (7) to reach was detected.

When the time required for the ultrasonic wave 7 to reach the object 8 through the above process is detected, the temperature detection unit 3 measures the atmospheric temperature in the storage tank 9 (190). Sound velocity, which is the velocity in the air of 7), was calculated through the following equation (200).

Sound velocity [m / s] = 331.5 [m / s] + 0.607 [m / (sec

When the sound velocity is calculated through the above process, the distance between the object 8 and the flow rate measuring device is calculated through the following equation (210).

S [m] = V _SONIC [m / sec] × t _SONIC [sec]

S in the above formula is the distance between the measuring object 8 and the flow measuring device, V _SONIC is the sound velocity which is the air velocity of the ultrasonic wave 7, and t _SONIC is the ultrasonic wave 7 up to the measuring object 8. Represents the time it takes to reach.

As such, the distance measured through a series of processes and the temperature of the oil measured by the temperature detector 3 are transmitted to the management computer so that the accurate volume of the flow rate in the storage tank 9 is displayed through the output unit.

6 is a cross-sectional view of a horn according to the present invention.

The horn 6 has a built-in ultrasonic sensor (5), the outer shape in the form of a parabolic shape to maximize the directivity of the sound wave during transmission to improve the output, when received reflected on the object 8 Sound waves can concentrate on the ultrasonic sensor 20 for reception, thereby improving reception sensitivity.

Currently commercially available ultrasonic sensors are waterproof and designed to have a directivity of 70 °, but due to the characteristics of the waterproof type, the output is reduced, and when received, the signal of the sound wave reflected and diffused by the measurement target 8 is weak. And the horn 6 is mounted to improve the reception sensitivity, but in order to obtain the maximum effect, the appearance of the horn 6 was maintained in the form of a parabola. The technical elements are as follows.

All sound waves have the property of reflection, refraction and diffraction like light.

Sound waves originating from a sound source spread out in all directions and have the form of a sphere when represented as a set of sound waves with the same output.

When the ultrasonic wave 7 is transmitted using the physical properties of the sound wave, the sound wave is concentrated in one place to maximize the divergence effect, and when the ultrasonic wave 7 is received, it is scattered and reflected on the object 8 during reflection. In order to focus the sound waves in one place, the shape of the horn 6 has the highest efficiency when the parabolic shape is maintained.

The horn (6) follows the parabolic formula of xy = ² , which is produced by the result calculated using the mathematical properties of the parabola. The parabola is a line connecting a point on the parabola at its focal point. Then, when the line is rotated around the tangent line at a certain angle with the tangent at that point, the straight line becomes orthogonal to the y-axis.

Considering the mathematical properties of the parabola in relation to the physical properties of the sound waves, as shown in FIG. 8, the sound waves emitted in arbitrary directions at the location of the sound source 10 are located on the inner wall of the parabola-shaped horn 6. When bumped, the nature of the reflection causes the direction to switch in the vertical direction rather than the original direction.

In Fig. 8, the straight portions are sound waves vertically concentrated by the parabolic horn 6 below, and the radial shapes are sound waves emitted from the actual sound source 10.

Therefore, the horn 6 having a parabolic shape can collect the sound waves scattered from the sound source 10 into the area to be measured, so that the output can be concentrated at the time of transmission and the directivity can be maximized. 6) Ultrasonic waves reflected by the target object 8 in a large area at the entrance side can be focused to a location where the parabolic focal point exists, that is, the receiving ultrasonic sensor 20 can improve reception sensitivity. .

9 is a state diagram showing a dispersion angle in which the horn 6 according to the present invention is mounted.

In the case where the horn is not attached to the ultrasonic sensor unit, the horn has a dispersion angle of about 60 °, which is a dispersion angle of the general transmitting ultrasonic sensor 11, and in the case where the general horn having a cone shape is mounted to the ultrasonic sensor unit 11, 45 When the parabolic horn 6 is attached to the ultrasonic sensor unit 11, the ultrasonic sensor unit 11 has a minimum dispersion angle of about 30 degrees, and reaches the unit area of the object 8 under measurement. It can be seen that the energy is the maximum value, so it is usually preferable to use the horn 6 having a dispersion angle of about 30 °.

In this way, the higher the ultrasonic energy reaching per unit area of the object under test 8, the more attenuation in the atmosphere can be overcome, and the longer the measurement is possible, and the larger the amount of reflected energy, the higher the ultrasonic sensor for receiving ( 20) also improves the reception sensitivity.

As described above, in order to survey a liquid such as a flow rate stored in a large-capacity storage tank without occurrence of an error, the ultrasonic wave 7 is reflected by the measurement target object 8 and the received data is processed by a microcontroller. It is a very useful invention that can calculate the volume by measuring the exact distance using statistical method.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited to the drawings shown.

Equipped with a measuring device that emits ultrasonic waves to measure the flow rate in a large storage tank such as a low oil tanker or oil tanker, the control unit uses the signal processing technique and arithmetic and statistical methods to control It improves the precision of measuring equipment and reduces the occurrence of errors in surveying, which can reduce economic losses in terms of inventory management.

Claims (6)

In the flow rate measuring method of the oil storage tank using ultrasonic waves, A first step of emitting an ultrasonic wave (7) to the object under test (8) by the transmitting unit (1) receiving the ultrasonic signal from the time processing recording circuit (13a); A second step of removing the direct wave by preventing the ultrasonic wave 7 emitted from the transmitter 1 from being received by the receiver 2 for a predetermined time; The third step of receiving the ultrasound (7) at the receiving unit 2 and detects the time required for the ultrasound (7) to reach the object to be measured 8: A fourth step of determining whether the reference value is exceeded by a timer built in the microcontroller of the controller 4 with respect to the change width between the detected time data and the previous time data and storing the detected time in a memory; A fifth step of detecting an average time from the plurality of pieces of data stored in the memory by removing a predetermined amount of maximum and minimum values; 6th step of calculating the ultrasonic sound velocity in the atmosphere after measuring the atmospheric temperature in the storage tank (9): And a seventh step of outputting the distance between the measured object 8 and the measuring device by multiplying the average speed of the ultrasonic wave 7 to reach the measured object 8 by the sound velocity of the ultrasonic wave. Flow Measurement Method of Oil Storage Tank Using Ultrasonic Wave. The method of claim 1, When the time detected by the timer exceeds the reference value, the number of errors increases by one, and when the number exceeds 10, further comprising an eighth step of setting a new reference value and storing it in the memory. How to measure the flow rate of a storage tank. The method of claim 2, If the number of errors does not exceed 10, the oil storage using the ultrasonic wave, characterized in that it further comprises an ninth step of transmitting an error message, and waits until the afterimage is removed and then moves to the transmitter (1) How to measure the flow of a tank. In constructing a flow measuring device of an oil storage tank using ultrasonic waves, The transmitter 1 which mounts the horn 6 to the ultrasonic sensor 11 for transmission and emits the ultrasonic wave 7 to the to-be-measured object 8, and attaches the horn 6 to the ultrasonic sensor 20 for reception. A receiver 2 for receiving the ultrasonic wave 7 reflected by the object 8 and a temperature detector 3 for detecting atmospheric temperature in the storage tank 9; and a signal based on the data measured above. An apparatus for measuring the flow rate of an oil storage tank using ultrasonic waves, characterized in that it comprises a measuring device and a control unit (4) for calculating a distance between a measuring object and a processing technique and an arithmetic and statistical method. The method of claim 4, wherein The shape of the horn (6) attached to the ultrasonic sensor is a flow measuring device of the oil storage tank using ultrasonic waves, characterized in that the configuration of the parabolic form using the result calculated using the formula y = ax ² . The method according to claim 4 and 5, The transmission ultrasonic sensor (11) is a flow rate measuring device of the oil storage tank using ultrasonic waves, characterized in that further expansion in all directions from the central sensor.