RU30974U1 - Ultrasonic device for measuring liquid level in tanks - Google Patents

Description

The device relates to instrumentation, in particular, to ultrasonic level meters, and can be used to measure the liquid level in tanks, including automobile and aviation (wing and fuselage) fuel tanks.

Known ultrasonic devices for measuring the level of liquid in tanks containing electro-acoustic transducer,

in contact with the outer surface of the bottom of the tank, connected to the first input of the electronic unit for transmitting and processing information, and a second electro-acoustic transducer in contact with the side surface of the tank at a level known to be lower than the minimum liquid level in the tank at a known distance L from the opposite wall of the tank, connected to the second input of the electronic unit for transmitting and processing information 1-5-3.

The disadvantages of the known devices is the limited scope and low accuracy.

The disadvantages of the known devices are explained as follows.

The use of known devices is possible only for those tanks whose bottoms allow horizontal installation of an electro-acoustic transducer. Otherwise, due to the fact that the reflection of the acoustic pulse from the liquid-gas interface and from the walls of the tank

occurs according to the laws of geometric acoustics, a signal repeatedly detected by the interface and the walls of the reservoir gets onto the electro-acoustic transducer, the exact calculation of the passage path of which is impossible.

The use of the known device is possible only for those tanks

on the side wall of which a second electro-acoustic transducer is possible.

Changes in fluid temperature, level of loading, wind load, deformation of the tank lead to a deviation of the true value of the measured base Lucm from the value of the measured base L in the calculation formula.

The technical essence of the closest to the proposed is an ultrasonic device for measuring the liquid level in the tank 4, containing an electro-acoustic transducer in contact with the outside

the surface of the bottom of the tank, connected to the input of the electronic unit

receiving and transmitting and processing information, and a pipe placed inside the tank coaxially to the contact surface of the electro-acoustic transducer.

The known device allows you to measure the liquid level at a non-horizontal position of the bottom of the tank. However, in this case, the known device has low accuracy. In addition, the known device does not allow measurement of low levels.

The disadvantages of the known device are explained as follows.

If the bottom of the tank is different from the horizontal, the pulse reflected from the gas-liquid interface propagates in accordance with the laws of geometric acoustics and arrives at the contact surface of the electro-acoustic transducer after reflections from the walls

t

pipe, as a result of which its transit time increases, and, therefore, the measured signal transit time depends on the angle of inclination of the tank bottom and does not correspond to the time of direct passage of the acoustic signal to the interface.

To ensure the same level of fluid in the pipe and tank in accordance with the laws of communicating vessels, the prototype proposed in the device prototype is perforated in the upper part of the vessel filled with gas, while in the lower part of the pipe located in the liquid there is a conical socket. Such a design limits the minimum measurable level, in particular, the levels below the conical socket cannot be measured. In addition, the presence of a conical bell leads to the appearance of an echo signal reflected from it, which complicates the noise-signal situation and makes it difficult to isolate useful signals reflected from the phase boundary.

The objective of the utility model is to eliminate these disadvantages. The technical result in this case is to increase the accuracy of measurements and expand the measurement range in terms of measuring small levels.

The achievement of the specified technical result is achieved by the fact that in the known device for measuring the liquid level in the tank, containing an electro-acoustic transducer in contact with the outer surface of the bottom of the tank, connected to the input of the electronic unit for transmitting and processing information, and a pipe placed inside the tank coaxially on the contact surface of an electro-acoustic transducer having perforation in a part located in the region of a reservoir filled with gas

The following features are introduced, namely: perforated pipe

a transducer, while an electronic sensor of the angle of inclination is introduced into the ultrasonic device, the output of which is connected to the second input of the electronic unit for transmitting and analyzing information.

The best results are achieved if the pipe diameter D, the diameter of the contact surface of the electro-acoustic transducer d, and the maximum measured level L are related by

59 ° L D

d L and also if the diameter of the pipe is O, the diameter of the perforations b and

radiation frequency f are related by

(s h s)

where C is the speed of sound in a working environment,

S is the surface area of the pipe per hole.

The achievement of the claimed technical result is explained as follows. Each angle of inclination of the tank and, accordingly, the deviation of the axis of the pipe from the vertical, for a given diameter of the pipe, the time

the passage of the reflected momentum and the true value

fluid level in the tank.

The ratio minimizes the emission of acoustic energy outside the pipe.

59 ° A D

The condition given that the solution of the main lobe

d L

directivity characteristics of a circular transducer of diameter d is 5

directivity of the emitter inside the pipe and, therefore, the absence of multiple re-reflections inside the pipe.

In papers 6,7, the propagation of a sound wave in a rigid pipe of circular cross section D perforated with holes was studied, and it was shown that under the condition

B ± "(± Ltf S I C)

where b is the diameter of the perforating hole;

S is the surface area of the pipe per hole;

f- radiation frequency;

C is the speed of sound in a working environment,

sound attenuation in the pipe can be neglected, and the field structure in the pipe does not differ from the field structure in the pipe without holes, i.e. there is practically no radiation from the holes into the region external to the pipe.

In practice, the “replace with the 0.1 sign is enough.

Figure 1 shows a block diagram of the proposed device. An ultrasonic level measuring device contains an electro-acoustic transducer 1, for example, described in 8, in contact with the outer surface of the bottom of the tank 2, connected to the first input of the electronic unit for transmitting and processing information 3, for example, similar to that described in 2.3, an electronic angle sensor tilt 4, for example, the horizon, described in work 9, the output of which is connected to the second input of the electronic unit for transmitting and processing information 3, perforated with a constant section along the length, rigidly connected to the bottom of the tank, installed coaxially to the contact surface of the electro-acoustic transducer 1, pipe 5, the diameter of which is D, the diameter of the contact surface of the electro-acoustic transducer d, the maximum measured level L,

the diameter of the perforation holes b and the radiation frequency f are related by the relations

59 ° A D

o, (/ Y

s h s)

The operation of the device is as follows. When you turn on the block of reception, transmission and processing of information 3 generates an electrical signal of a given frequency f, which is fed to the electro-acoustic transducer 1, which converts the electrical pulse into acoustic vibrations. The latter pass through the wall of the tank 2, canalized by a perforated pipe 5, propagate in the working medium 6, reach the desired boundary of the working medium 7, are reflected from it and also, channelized inside the pipe 5, come to the wall of the tank 2, pass through it and are received by the electro-acoustic transducer 1. The electro-acoustic transducer 1 converts the acoustic vibrations reflected from the interface 7 into an electrical pulse, which is fed to the first input of the transmit-receive and information processing unit 3. One temporarily, data from the output of the electronic sensor of the angle of inclination 4 is received at the second input of the electronic unit for transmitting and processing information 3; in block 3, the received signals are processed and the distance L is calculated by the formula

6

C is the speed of sound in a working environment,

.t is the signal transit time to the liquid-gas interface and vice versa.

The presence of an electronic angle sensor allows you to solve

the stated technical task, namely, to increase the accuracy of measuring the liquid level in the tank and with size ratios that differ from the stated ones, while the design of the pipe provides measurement of small levels.

Sources of information.

1. Certificate of the Russian Federation for utility model No. 7497.

2.M.Ya. Andreev, Yu.A. Koryakin, I.L. Rubanov. Ultrasonic level meters UZU-2 and UZU-2T. Sensors and systems, No. 1, 2002

3.M. Andreev, Yu.Koryakin, I.Rubanov, Yu.Fleer, L.Voytasik. Ultrasonic level gauges and systems based on them. IT - solutions in the oil and gas industry. Special Supplement to No. 6 Oil and Capital, 2002

4. U.S. Patent No. 5119676.

5.M.D.Smaryshev. Orientation of sonar antennas. L., Shipbuilding, 1973

6.I.A. Urusovsky. Sound radiation from a perforated tube, inside which a harmonic wave propagates. Acoustics Well, 1972, v. 18, No. 3.

7.I.A. Urusovsky. Abstract for the degree of Doctor of Physical and Mathematical Sciences. M., Acoustic Institute. Academician NAAndreev, 1993

8. Certificate of the Russian Federation for utility model No. 23541.

USEFUL MODEL FORMULA

1.Ultrasonic device for measuring the liquid level in the tank, containing an electro-acoustic transducer in contact with the outer surface of the bottom of the tank, connected to the first input of the electronic unit for transmitting and processing information, and a pipe placed inside the tank coaxially to the contact surface of the electro-acoustic transducer and having a perforation in part of the pipe located in the gas phase, characterized in that the pipe is perforated along the entire length and having

along the entire length a constant section rigidly connected to the bottom of the tank at the point of contact with electro-acoustic

the transducer, while an electronic sensor of the angle of inclination is introduced into the ultrasonic device, the output of which is connected to the second input of the electronic unit for transmitting and analyzing information.

2. The ultrasonic device according to claim 1, characterized in that the diameter of the pipe D is connected with the diameter of the contact

the surface of the electro-acoustic transducer and

maximum measured level L ratio

t

59 ° I D

tg -

 d L

3. The ultrasonic device according to claim 1, characterized in that the pipe diameter D, the diameter of the perforating holes b and the radiation frequency f are related by the ratio

where C is the speed of sound in a working environment;

S is the surface area of the pipe per hole.

s (s)

Claims (3)

1. An ultrasonic device for measuring the liquid level in the tank, containing an electro-acoustic transducer in contact with the outer surface of the bottom of the tank, connected to the first input of the electronic unit for transmitting and processing information, and a pipe placed inside the tank coaxially to the contact surface of the electro-acoustic transducer and having a perforation in part of the pipe located in the gas phase, characterized in that the pipe is perforated along the entire length and having a constant along the entire length th section is rigidly connected to the tank bottom at the point of contact with it electroacoustic transducer, the ultrasound device is entered in the electronic tilt sensor, whose output is connected to the second input of the electronic unit receiving a transmission and analysis. 2. The ultrasonic device according to claim 1, characterized in that the pipe diameter D is associated with the diameter d of the contact surface of the electro-acoustic transducer and the maximum measured level L ratio D ≥ d

where λ is the sound wavelength in the working fluid. 3. The ultrasonic device according to claim 1, characterized in that the pipe diameter D, the diameter of the perforating holes b and the radiation frequency f are related by the ratio

where C is the speed of sound in a working environment; S is the surface area of the pipe per hole.