UA106840C2 - DEVICE FOR MEASURING LIQUID level IN gas PIPELINE cavity - Google Patents

Abstract

The invention relates to the field of process measurements and may be used for determining the actual liquid level in processing gas line cavities. Device for measuring the level of liquid in the cavity of the pipeline consists of an ultrasonic piezoelectric transducer and a measuring unit and is equipped with an acoustic unit, installed on the pipeline with a seal rubber sleeve, in the body of which capability of contact with the pipeline surface a sensor and an ultrasonic piezoelectric transducer are mounted, this is pressed to the surface of the pipeline with a spring and has in the contact point a concave acoustic lens, wherein the measuring unit is placed above the ground surface and connected to the acoustic unit through a connector built into the column of electrochemical protection, and contains a module working on basis of algorithm for determining the liquid level from the maxima of constructed envelope curve of dynamics of the ultrasonic waves propagation and the actual value of fluid temperature. Realization of the proposed device allows to measure the liquid level in the cavity of the pipeline with high precision and provides an opportunity to measure the liquid level in the pipeline cavity that is less than 10.6 cm without discontinuation of the pipeline wall and its excavation.

Description

The invention belongs to the field of technological measurements and can be used to determine the actual liquid level in the cavities of technological gas pipelines.

A well-known device for continuous control of the liquid level in closed containers under pressure |(|1Й, which consists of two ultrasonic transducers (radiating and receiving) designed to emit and receive an asymmetric Lamb acoustic wave in the container wall, as well as a high-frequency generator .

The disadvantage of this device is the difficulty of installation on the gas pipeline pipe and significant geometric dimensions due to the presence of two ultrasonic transducers. In addition, the device is designed to determine the boundary of phase separation only in vertically placed pipelines, which significantly limits its use on process and main gas pipelines. Another disadvantage of the device is that when measuring the level of the liquid column, the temperature of the medium is not taken into account, as one of the important factors that significantly affects the speed of propagation of ultrasonic vibrations in the medium.

In the conditions of operation of technological and main pipelines, determining the level of liquid in their cavities is very important, since the presence of liquid negatively affects the operation of all nodes of the gas transportation system, complicates the process of conducting intra-pipe diagnostics of main gas pipelines and significantly worsens gas quality.

The presence of liquid in the cavity of the gas pipeline is one of the factors that significantly reduces the efficiency of the gas transportation system. On the horizontal and descending sections of the route, the liquid moves in the form of a film along the walls of the pipe. The presence of a liquid film significantly increases the hydraulic resistance of the gas flow. The largest amount of liquid accumulates in the ascending sections of the gas pipeline, forming a hydraulic jam, partially or completely blocking the section of the pipe, increasing hydraulic resistance and hydrostatic pressure drop.

In addition, the presence of water in the gas pipeline significantly complicates the procedure of intra-pipe diagnostics of the pipeline, since in this case it is possible to damage or destroy the cleaning and diagnostic pistons, which will undergo hydraulic shocks. In areas of air and river transitions, the cleaning piston, moving in the gas pipeline, will accumulate a significant volume of water in front of it, which can lead to a significant increase in internal stresses in the wall of the gas pipeline and, as a result, its destruction.

Also known is the method and device for measuring the levels of multicomponent media |21, the principle of which is that the generator forms ultrasonic waves that are emitted into the measuring medium by means of a sensitive element. The sensitive element is also used to receive ultrasonic waves reflected from the environment.

To increase the accuracy of measurements and ensure the possibility of determining the levels of multicomponent media, ultrasonic waves are generated at different frequencies in the range from 10 MHz to 130 MHz, which is implemented using a variable frequency generator. The sensitive element is made in the form of a long segment. The position of the boundaries of multicomponent media is determined by analog-to-digital conversion and amplitude detection of the received signal. The value of the frequency range and the step of changing the frequency are chosen based on the technical capabilities of the implementation of the measuring equipment and the maximum values of the measured values.

The disadvantage of this device is the impossibility of measuring the levels of media when their thickness is less than 0.8 m, the need for additional calculations to determine the step of changing the frequency of oscillations. In addition, the large size of the sensitive element makes it impossible to carry out measurements on gas pipelines of small diameter. The lack of compensation for the effect of the temperature of the measuring medium on the measurement results and negative interference in the pipeline operation due to the need to install a sensitive element in the gas pipeline cavity can also be attributed to the disadvantages.

Also known is the device for determining the liquid level in the pipeline cavity (|Z), which was chosen as a prototype. It consists of an ultrasonic piezoelectric transducer capable of generating and receiving ultrasonic oscillations, a generator-receiver path and a measuring unit. A high-frequency voltage pulse is applied to the piezoelectric transducer, which generates directional ultrasonic oscillations. A piezoelectric transducer, which is located in the lower part of the pipeline, emits ultrasonic vibrations through the wall of the pipeline into the water. Ultrasonic vibrations reflected from the surface of the liquid and from the inner surface of the pipeline wall are received by an ultrasonic transducer, which converts them into electric voltage pulses, which, after amplification in the generator-receiver path, are fed to the measuring unit. The measuring unit calculates the value of the liquid level in the pipeline cavity based on the measured value of the time of appearance of the mentioned pulses and the corresponding values of the speed of propagation of ultrasonic vibrations in the material of the pipeline wall and liquid.

The disadvantages of this device include the following: - the temperature of the liquid, the level of which is measured, is not taken into account, as one of the important factors that affects the speed of propagation of ultrasonic waves in the environment; - the design of the acoustic transducer does not ensure reliable long-term acoustic contact between the transducer and the pipe surface, provided it is installed on operating underground gas pipelines under the influence of aggressive environments; - due to the use of a low-frequency acoustic transducer and the occurrence of the phenomenon of reverberation of acoustic vibrations in the pipe wall, it is impossible to measure the value of liquid less than 4 inches (10.16 cm).

The invention is based on the task of creating such a device, in which a new design of primary transducers and a method of information analysis would allow high-precision measurement of the liquid level in gas pipeline cavities without breaking the integrity of the pipeline wall and digging it up.

The task is solved as follows. In the known device, a temperature sensor is additionally introduced to increase the accuracy of measuring the speed of propagation of ultrasonic waves, which is in contact with the outer surface of the gas pipeline at the point of attachment of the ultrasonic piezoelectric transducer. The acoustic unit of the device consists of a case pre-filled with a substance (for example solidol) to ensure acoustic contact of the ultrasonic piezoelectric transducer with the gas pipeline pipe.

A sealing cuff is placed in the housing of the acoustic unit of the device, which prevents the penetration of aggressive substances contained in the soil to the internal elements of the acoustic unit. This design of the acoustic unit allows for reliable and long-term acoustic contact of the ultrasonic piezoelectric transducer with the underground gas pipeline. The piezoelectric transducer is spring-loaded to ensure reliable contact between it and the outer surface of the pipeline wall.

Additionally, to ensure reliable acoustic contact and reduce the loss of acoustic vibrations at the piezoelectric element-steel separation boundary, ultrasonic piezoelectric

The transducer is equipped with a concave acoustic prism made of a copper plate, which is placed between the piezo element and the outer surface of the gas pipeline, while the radius of curvature of the concave surface of the prism is equal to the outer radius of the gas pipeline pipe. In order to reduce the influence of the phenomenon of reverberation of acoustic vibrations in the pipe wall, additionally increase the accuracy of measurement and ensure the possibility of measuring the liquid level in the gas pipeline cavity, which is less than 10.6 cm, it is proposed to measure the time of passage of acoustic vibrations in the liquid according to the maxima of the constructed envelope curve of the dynamics of the reflection of ultrasonic waves, and also used a piezoelectric ultrasonic transducer with a resonant frequency of 2.5 MHz.

To measure the liquid level in the cavity of the gas pipeline without digging it up, the connecting conductors from the acoustic unit installed on the gas pipeline are brought out through the column of electrochemical protection, which is additionally equipped with a plug for connection to the measuring unit.

The measuring unit of the device contains a module that determines the level of the liquid by constructing the envelope curve of the dynamics of the reflection of ultrasonic waves from the surface of the separation of media, and the determination of the time of passage of acoustic waves T in the measuring medium is carried out according to the maxima of the envelope, taking into account the temperature of the liquid.

In fig. 1 shows the diagram of the device for determining the liquid level in the cavity of the gas pipeline.

The device for measuring the liquid level in the gas pipeline cavity consists of an acoustic unit 1, which is attached to the lower part of the gas pipeline 2, and a measuring unit 3. The cable of the acoustic unit 4, which is used to connect the acoustic unit 1 to the ground part, is led into the column of the electrochemical protection 5, and is connected to the measuring unit C by means of the cable of the measuring unit 6 through the connector 7, which is mounted in the wall of the column of electrochemical protection 5.

The schematic structure of the acoustic unit is shown in fig. 2. The ultrasonic piezoelectric transducer 8 is located concentrically in the cylindrical groove of the housing 9 and is spring-loaded by a spring 10. The housing of the acoustic unit is equipped with a sealing rubber cuff 11. With the help of a clamp 12, a reliable attachment of the housing 9 to the wall 13 of the gas pipeline pipe 2 (Fig. 1) of the protected insulation 14. The temperature sensor 15, for example a thermocouple, is located in the housing 9 near the ultrasonic piezoelectric transducer 8 and is in contact with the outer surface of the wall 13 of the gas pipeline pipe. Two connecting conductors 16 of the ultrasonic piezoelectric transducer 8 and conductors 17 of the temperature sensor 15 converge in the cable of the acoustic unit 4. The hole in the housing 9 for the output of the cable of the acoustic unit 4 is sealed with the help of a rubber washer 18 and a fitting 19. Rubber gasket 20, which is located between the fitting 18 and the body 9, ensures reliable sealing of the acoustic unit.

The schematic structure of the ultrasonic piezoelectric transducer is shown in Fig. 3.

The ultrasonic piezoelectric transducer 8 (Fig. 3) consists of a metal housing of the transducer 21, a piezoceramic plate 22 made of barium titanate TBK-3 with a diameter of 20 mm, the resonance frequency of which is 2.5 MHz, a damper 23 and a concave acoustic prism 24, made of a copper plate with a diameter of 20 mm, while the radius of curvature B of the concave surface in contact with the outer surface of the gas pipeline is equal to the outer radius of the pipe of the same gas pipeline.

The device works as follows. The acoustic unit 1 (Fig. 1) is pressed against the outer surface of the gas pipe 2 in its lower part at the place of the most likely water collection by means of a clamp 12. The insulation 14 of the wall of the gas pipeline 13 of the lower part of the pipe of the gas pipeline 2 at the point of contact of the ultrasonic piezoelectric transducer 8 and the temperature sensor 15 is cleaned before installing the acoustic unit. The force of pressing the acoustic block to the gas pipeline pipe is selected so that due to the deformation of the cuff 11, reliable sealing of the cavity of the housing 9 of the acoustic block 1, previously filled with a substance to ensure acoustic contact, is ensured. The spring 10 ensures reliable contact of the ultrasonic piezoelectric transducer 8 with the outer surface of the wall 13 of the gas pipeline pipe 2. The hole through which the cable 4 passes, which connects the two conductors 16 of the ultrasonic piezoelectric transducer 8 and the conductors 17 of the temperature sensor 15 of the acoustic unit 1 , is sealed by screwing the fitting 19 into the hole of the housing 9 with a thread, which deforms the rubber washer 18 and the rubber gasket 20, thus pressing them to the cable of the acoustic unit 4 and the housing 9. The cable of the acoustic unit 4 is mounted at the other end in the column of electrochemical protection. The measuring unit C is connected with the cable of the measuring unit 6 to the cable of the acoustic unit 4 using the connector 7.

Zo The device for measuring the liquid level in the cavity of the gas pipeline works as follows.

The piezoelectric transducer 8 (Fig. 2) of the acoustic unit 1 (Fig. 1), which is supplied with a short-term high-voltage pulse from the measuring unit 3, generates ultrasonic acoustic waves that propagate in the wall of the gas pipeline 2, in which liquid and gas are located. At the liquid-gas interface, acoustic ultrasonic waves that have passed through the wall of the gas pipeline and the liquid will be partially reflected or refracted. Acoustic ultrasonic waves reflected from the liquid-gas separation boundary, having passed the return path, will also undergo partial reflection and refraction at the liquid-gas pipeline separation boundary. The refracted ultrasonic waves that passed through the wall of the gas pipeline fall on the piezo transducer.

Ultrasonic waves reflected from the boundary between the liquid and the wall of the gas pipeline, after passing through the liquid in the gas pipeline, are again reflected from the boundary between the liquid and gas and propagate in the opposite direction to the wall of the gas pipeline, where at the boundary between the liquid and the wall of the gas pipeline, they are re-emitted. reflection and refraction. The refracted ultrasonic waves, having passed through the wall of the gas pipeline, fall on the piezo transducer.

The piezo transducer converts the ultrasonic waves that hit it into electrical pulses. The latter are transmitted through the conductors 4 to the measuring unit 3, where they are amplified and visualized on a graphic display of the dynamics of the passage and reflection of ultrasonic waves from the liquid-gas separation surfaces, as well as the construction of the envelope curve of the dynamics of the reflection and passage of ultrasonic waves |4, 51.

In fig. 4 shows the stages of construction of the envelope curve of the dynamics of the reflection of ultrasonic waves from the surface of separation of media.

The construction of the enveloping curve of the dynamics of the reflection of ultrasonic waves from the surfaces of separation of media in the measuring unit takes place in three stages.

The first stage (Fig. 4, a) consists in constructing the actual curve of the dynamics of the reflection of ultrasonic waves from the surfaces of separation of media. On this curve there will be pulses of multiple reflections in the walls; pipeline 13, which have both positive and negative values, which makes it much more difficult to fix the time T.

At the second stage (Fig. 4, b), the lower (negative) part of the half-waves of multiple reflections in the pipeline wall (in Fig. 2, b are depicted by a thin line) is built symmetrically relative to the axis

OH.

The envelope of the curve of the dynamics of the reflection of ultrasonic waves from the surfaces of separation of media is constructed at the third stage (Fig. 4, c) according to the maxima of the half-waves of the dynamics of the reflection of ultrasonic waves from the surfaces of separation of media.

At the same time, the measuring unit measures the temperature of the liquid in the gas pipeline using a temperature sensor located in the acoustic unit.

The level of the liquid in the gas pipeline will be equal to half the product of the coefficient of dependence of the speed of propagation of ultrasonic waves in the liquid on its temperature, the temperature of the liquid, the speed of propagation of ultrasonic waves in the liquid under normal conditions and time T, which is equal to the time of passage of ultrasonic waves from the piezoelectric of the transducer to the boundary of the liquid-gas separation and in the opposite direction and is measured by the measuring unit after constructing the enveloping curve of the dynamics of the reflection of ultrasonic waves from the separation surfaces of the media (Fig. 4, c).

The coefficient of dependence of the speed of propagation of ultrasonic waves in a liquid on its temperature and the value of the speed of propagation of ultrasonic waves in a liquid under normal conditions are selected from reference data |b|.

Sources of information: 1. Patent of the Russian Federation Mo VO 2383869 IPC a 01 E 23/28. 2. Patent of the Russian Federation Mo VO 2184352 IPC C 01 E 23/28. 3. Patent of the United States of America Mo 5319972 C 01E 23/00. 4. Karpash O.M. Development of a system assessment of liquid level in cavities of operating gas pipelines. I.V. Rybytskyi, A.V. Yavorskyi, M.O. Karpash, R.Yu. Banakhevich // Gas industry. Pipeline transport. Appendix "Diagnostics of objects of gas transport systems". - Publishing house "Gazoil Press", "Gas Industry" - 2011. - P. 13-15. IB5M 0016-5581. 5. Banakhevich R.Yu. Liquid level monitoring system in gas pipeline cavities / R.Yu.

Banakhevich, O.M. Karpash, I.V. Rybytskyi, A.V. Yavorsky //Material! MY international scientific and technical conference "Reliability and safety of main pipeline transport" (November 22-25, 2011). - Novopolotsk: PTU. -2011. -WITH. 133-134. b. Non-destructive control and diagnostics: reference book / (Klyuyev V.V., Sosnyn F.R., Filinov

V.N. and others; under the editorship V.V. Klyueva. - M.: Mashinostroenie, 1995. - 448 p.

Claims (2)

FORMULA OF THE INVENTION A device for measuring the liquid level in the cavity of a gas pipeline, consisting of an ultrasonic piezoelectric transducer and a measuring unit, which is characterized by the fact that it is equipped with an acoustic unit installed on the gas pipeline with a rubber sleeve seal, in the body of which, with the possibility of contact with the surface of the gas pipeline, there are installed a temperature sensor and an ultrasonic piezoelectric transducer, which is pressed against the surface of the gas pipeline by a spring and has a concave acoustic prism at the point of contact, while the measuring unit is placed above the surface of the earth, connected to the acoustic unit through a connector mounted in the column of electrochemical protection , and contains a module whose work is based on the algorithm for determining the liquid level based on the maxima of the constructed envelope curve of the dynamics of the passage of ultrasonic waves and the actual value of the liquid temperature. And oh, and, and! ku si sh Fig. 1 Screen of the device for determining the liquid level in the cavity of the gas pipeline KO. Myni i l i o y Sha shi - shi av av Y o Y es A OSY ze : rak : 1. AH yu y, Fig. 2 Schematic structure of the acoustic block KA / / koi and pypnky, and KK and and ni zhd is. By KO t Kar r n Shk, Al I m ra y z, u ra : - ry Ky y g 7 y ky y y r sh- i | in o and in I; and xx year - in . I I 3 i ui y t ia a y y y M y I Kar r rak v i y i y I "Z sho sha I : y M r : K U y m i yak ra Y z ve y Te ra b bo i yes and ЖЖ uja Uushk Sho Ye den shi Pen 76 ie and E Pr iy Fig. C Schematic structure of an ultrasonic piezoelectric transducer (c) A y I y IN ! Still shi NN A Ko b A A Some NN NE Me Her | With MORE dm Where. She EVIEUNAENENI WOULD BE GUILTY EE 0 y Z. Snya sno 2 -o n zn yazhzhhhhya. residential area "and ! in Fig. 4 Stages of construction of the envelope curve of the dynamics of the reflection of ultrasonic waves