RU134317U1 - MAGNETOSTRICTIONAL LEVEL METER - Google Patents

Abstract

1. Magnetostrictive level gauge, characterized in that it includes a sensitive element with a sound guide made of magnetostrictive material placed in a magnetically permeable tube, an autonomous measuring module located at a known distance from the bottom of the tank, a piezoelectric receiver, and a unit for calculating the time interval for the passage of ultrasonic vibrations from the surface (interface between fractions ) liquid to the bottom of the tank, at least one float, and in the floats placed active autonomous modules that measure the temperature y and the fluid pressure at the location, with measuring circuits controlled by microprocessors, sound pipe excitation coils and magnetic blocks of n permanent magnets (ring magnets with a radially oriented magnetic field), where n = 1, 2 ... i, placed around the tube with the possibility of movement along it, and also additionally contains the "Radomsky anchor", which is a rack with a heavier base, three pointed conical supports and a sealed volume in the upper part to accommodate an autonomous module. 2. The magnetostrictive level gauge according to claim 1, characterized in that it has an autonomous power source, a digital storage circuit for the measurement results, a radio modem and an antenna.

Description

The claimed technical solution relates to measuring equipment and can be used to measure the liquid level mainly in tanks.

A device for measuring the level of a liquid using ultrasonic waves for its operation is known. The device contains a level gauge tube, a special sound duct in the form of a metal core, on which the primary winding of the linear transformer is located, an electro-acoustic transducer loaded on the sound duct, and also a float covering the level gauge tube. The block of secondary electronic equipment includes a pulse generator, a pulse shaper of reflected signals, a logic block and other elements, the content of which depends on the measurement scheme of the time interval [O. Babikov Ultrasonic monitoring devices. - L .: Engineering, Leningrad Branch, 1985, p. 117; A.S. USSR No. 620828, cl. G01F 23/28, 1978].

The disadvantages of this device for measuring the liquid level are low accuracy when measuring large levels, the inability to measure more than one level, which is especially true for liquids consisting of several fractions.

A known ultrasonic level gauge containing a rectilinear magnetostrictive sound pipe, signal electro-acoustic transducer, a float element with a polarizer, a wave reflector, a recording amplifier, a reading amplifier, a coding and computing unit. The coding and computing unit is connected to the sound pipe through a recording amplifier. The other output of the coding and computing unit is connected through a read amplifier to the terminals of the signal electro-acoustic transducer. The signal electro-acoustic transducer is fixed at a reference distance from the end of the sound duct and is connected to the terminals of the reading amplifier. At the other end of the sound duct, a wave reflector is rigidly fixed. A float element with a polarizer is placed between the signal electro-acoustic transducer and the wave reflector [RF Patent No. 2213940, cl. G01F 23/28, G01F 23/30, 2003].

The disadvantages of this device are the large supply voltages necessary for the formation of an ultrasonic wave by an electro-acoustic transducer (especially with a long length of the sound duct), which requires solving the intrinsic safety problem, low measurement accuracy, since the uncertainty of the location of the wave reflector relative to the bottom of the capacitor, the impossibility of measuring several levels, which is typical for liquids consisting of several fractions.

Known float level gauge containing conductive sound pipe, processing unit, a float mounted on the sound pipe with the ability to move along it, and a conductive element. In addition, the level gauge contains an alternating current generator, an acoustic transducer connected to the upper end of the sound duct, a discriminator-shaper, an intermediate transformer, and the float contains an electric pulse generator, a rectifier located concentrically with the hole of the float, a toroidal transformer and an excitation coil connected to the electric pulse generator [RF patent No. 2463566, cl. G01F 23/28, 2012].

The disadvantages of this level gauge are the low accuracy of the measurement, since the distance from the top cover of the tank (which may undergo deformation from temperature, overpressure, etc.) to the float is measured, and not the distance from the float to the bottom of the tank, the inability to measure several levels, which typical for liquids consisting of several fractions, the inability to measure additional parameters of the liquid (liquid fractions), such as temperature, pressure, density, etc.

Of the known technical solutions, the closest in purpose and technical nature to the claimed object is a magnetostrictive level gauge containing a sensing element with a sound duct made of magnetostrictive material placed in a dielectric tube, a winding wound on a dielectric tube, at least one float with a magnetic block of n constants magnets, where n = 1, 2 ... i, placed around the insulating shell with the possibility of movement along it, an electric pulse generator, ur determination unit a ram, a piezoelectric receiver, a digital pulse generator from the converted electric vibrations from the piezoelectric receiver, a unit for determining a time interval between the time of formation of the magnetoelastic effect and the time of formation of the piezoelectric effect [RF Patent No. 2222786, cl. G01F 23/28, 2004].

The disadvantage of this magnetostrictive level gauge is the low measurement accuracy (the distance from the top cover of the container, which may undergo deformation from temperature, gauge pressure, etc., to the float, and not the distance from the float to the bottom of the container, is not taken into account, the change in the length of the sound duct from temperature is not taken into account ), the impossibility of measuring at the location of the float additional liquid parameters (liquid fractions), such as temperature, pressure, density, etc., as well as a relatively high cost, falseness and low reliability sensing element (especially when long length) due to the need to accommodate the entire length of the winding.

The problem to which the claimed technical solution is directed is to create a magnetostrictive level gauge that can improve the accuracy of measuring the liquid level (levels of liquid fractions), in particular by compensating for the error associated with the temperature change in the length of the sound duct, and measure additional parameters of the liquid (fractions liquids) such as temperature, pressure, density, etc.

The task is achieved due to the fact that the magnetostrictive level gauge contains a sensitive element with a sound conductor made of magnetostrictive material placed in a magnetically permeable tube, an autonomous measuring module located at a known distance from the bottom of the tank, a piezoelectric receiver, and a unit for calculating the time interval of passage of ultrasonic vibrations from the surface (fraction interface ) liquids to the bottom of the tank, at least one float, and active autonomous modules with measured circuits controlled by microprocessors that measure the temperature and pressure of the liquid at the location, and the excitation coils of the sound pipe and magnetic blocks of n permanent magnets (ring magnets with a radially oriented magnetic field), where n = 1, 2 ... i, placed around the tube with the possibility moving along it. It also additionally contains a “Radomsky anchor”, which is a rack with a heavier base, three pointed conical supports and a sealed volume in the upper part for placing an autonomous module.

The technical result provided by the given set of features is to increase the accuracy of measuring the level (interface of fractions) by directly measuring the depth of the liquid, and not the distance from the surface of the liquid to the top cover of the installation nozzle of the tank, which changes its configuration under the influence of various factors (temperature, pressure etc.), compensation for the error caused by the temperature coefficient of expansion of the sound duct. Functionality expanded by measuring additional parameters of liquid fractions (temperature, pressure, density, etc.).

In addition, according to the claimed technical solution, the piezoelectric receiver can be connected to a microprocessor, which in turn is connected to an autonomous power source, non-volatile memory and a radio modem.

The essence of the proposed technical solution is illustrated using graphic materials in which:

- in FIG. 1 shows a functional diagram of the implementation of a magnetostrictive level gauge;

- in FIG. 2 shows a functional diagram of an active autonomous module with measuring circuits under the control of a microprocessor and a sound pipe excitation coil;

- in FIG. Figure 3 shows the basic geometric parameters of a magnetostrictive level gauge, which are important for understanding its operation.

The magnetostrictive level gauge consists of a sensitive element, which in turn contains a piezoelectric receiver 2 mounted on the upper end of the sound duct 3 in the form of a wire of magnetostrictive material, not fixed in the lower part, placed in a magneto-permeable sheath 4. The sound duct can also be made in the form of a rod, but in most designs prefer wire because of its flexibility (especially for large measuring ranges, i.e. with a long sound guide), which makes transportation easier magnetostrictive level gauge. A float (s) 6 is placed (placed) on the magnetically permeable shell 4 and can be moved along it (and thus along the sensing element), a communication coil, an autonomous module under the control of microprocessor 5, and a magnet block 7 made of a ring magnet with a radially oriented magnetic field or n permanent magnets, where n = 1, 2 ... i.

The lower part of the magnetically permeable shell 4 ends with a sealing end device 12, to which the load 13 is attached using a stud 14.

The lower part of the magnetically permeable shell 4 with the end device 12 and the load 13 is included in the Radomsky anchor structure (rack 11 with a weighted base, three pointed cones and a sealed volume 9 fixed in the upper part of the rack with an autonomous module controlled by microprocessor 8 and a magnetic block 10) .

To the output of the piezoelectric receiver 2, a block for determining the time interval 16 is connected, to which, in turn, a block for determining the level 15 is connected.

The upper part of the magnetically permeable shell 4 with a piezoelectric receiver 2, time interval determination units 16, and a level determination unit 15 is closed by a hermetic casing 1, which, with the help of a collet clamp 17, which allows the device to initially be set in the desired position relative to the armature, is fixed on the cover 18, which in turn attached to the top of the tank 19.

The float (floats) 6 float on the surface of the liquid 20 (at the interface of the liquid fractions).

Stand-alone module 5 (8) consists of liquid parameters sensors 21 and 22, a stand-alone power source 23, a microprocessor 24, an energy storage device 25, a pulse generating circuit 26, an inductor 27 wound on a sleeve into which a magnetically-permeable sheath 4 with sound duct 3 is passed.

The claimed technical solution is illustrated in the interaction between the individual elements in the process.

Standalone module 5 to ensure high energy efficiency most of the time is in low power mode (sleep mode) and only occasionally activated, forms a coded pulse sequence, which through the inductor surrounding the sensing element, causes a magnetic field, which, interacting with a constant magnetic field magnet (magnets), causes ultrasonic vibrations in the sound pipe propagating through the sound pipe up and down, and below or reflected from the end of the twin-turbo and also go up. Thus, at the output of the piezoelectric receiver from each autonomous module, two signals are received, delayed from each other by twice the transit time of ultrasonic vibrations from this autonomous module (for example, it is located on the surface of the liquid) to the lower end of the sound duct. However, since the sound duct is fixed from above to the container lid, the distance from the lower end of the sound duct to the bottom of the container can change with a change in temperature, causing a change in the length of the sound pipe, and other factors causing deformation of the roof of the container, so the depth of the immersed part of the sound pipe will also change, and therefore and the doubled time of passage of ultrasonic vibrations from this autonomous module to the lower end of the sound duct will change, because it is possible to change the length of the part of the sound guide located below the magnetic system of the autonomous module. In order to eliminate this error, another stand-alone module 8 is used, rigidly fixed relative to the bottom of the tank.

The calculation of the liquid level is carried out in accordance with the ratio (see Fig. 3):

Where

h is the distance from the measuring float to the bottom of the tank, m;

h ₁ - distance from the measuring float to the lower end of the sound duct, m;

h ₂ - distance from the measuring system of the armature to the lower end of the sound duct, m;

h ³ - distance from the measuring system of the armature to the bottom of the tank, m;

V _sv is the speed of sound in the sound duct, m / s.

The distance from the measuring system of the armature to the bottom of the tank ³ can be measured with high accuracy when the meter is initially placed in the tank with liquid as a result of linking a specific level gauge to the tank by measuring the level with a control tape measure relative to the high-altitude stencil according to the passport and calibration table. The value of this quantity is entered into the level determination unit and is used for calculations.

и

. С учетом кодирования принимаемых пьезоприемником ультразвуковых колебаний, производится разделение информации от каждого из автономных модулей, поэтому можно измерять нескольких уровней (границ раздела фаз жидкости) одновременно, причем в кодированной информации от каждого из них содержатся дополнительные параметры жидкости в точке расположения каждого из автономных модулей.The position of the lower end of the sound duct during operation can change due to changes in the length of the sound duct when the temperature changes, the roof of the container deforms when the temperature, pressure, and mechanical deformations change, but this will not introduce a measurement error, since this error will be compensated for when subtracting delays

and

. Taking into account the coding of ultrasonic vibrations received by the piezoelectric receiver, information is separated from each of the autonomous modules, therefore it is possible to measure several levels (liquid phase boundaries) at the same time, and the encoded information from each of them contains additional liquid parameters at the location of each of the autonomous modules.

The operation of the magnetostrictive level gauge can be understood in more detail by considering the interaction between its individual elements.

The microprocessor 24 of the autonomous module most of the time is in the low power consumption mode (sleep mode) and only occasionally activates, reads the parameters measured by sensors 21 and 22 (for example, temperature and pressure), issues a command to store energy to the drive 25 from the autonomous power source 23 and The necessary moments are triggered by the transmission pulse formation circuit 26, which connects the energy storage device to the inductor 27 forming a magnetic field, as a result of the interaction of which with the magnetic th field of the permanent magnet (e.g., 7) and the magnetostrictive effect ultrasonic vibrations occur in the acoustic line. The ultrasonic vibrations reaching the piezoelectric receiver 2, due to the piezoelectric effect, cause voltage pulses at the output of the latter, which are fed to the input of the unit for calculating the time interval for the passage of ultrasonic vibrations from the surface (interface of the fractions) of the liquid to the bottom of the tank 16, which calculates this time interval and delivers it to the level determination unit 15, the results of which can be displayed on an indicator device (for example, a digital type), or transferred for storage and display otrebitelyu. Additional liquid parameters transmitted from the sensors can be used in the algorithm for calculating the level determination unit, or transmitted to the consumer.

Claims (2)

1. Magnetostrictive level gauge, characterized in that it includes a sensitive element with a sound guide made of magnetostrictive material placed in a magnetically permeable tube, an autonomous measuring module located at a known distance from the bottom of the tank, a piezoelectric receiver, and a unit for calculating the time interval for the passage of ultrasonic vibrations from the surface (interface between fractions ) liquid to the bottom of the tank, at least one float, and in the floats placed active autonomous modules that measure the temperature y and fluid pressure at the location, with measuring circuits controlled by microprocessors, sound pipe excitation coils and magnetic blocks of n permanent magnets (ring magnets with a radially oriented magnetic field), where n = 1, 2 ... i, placed around the tube with the possibility of movement along it, and also additionally contains the “Radomsky anchor”, which is a rack with a heavier base, three pointed conical supports and a sealed volume in the upper part for placing an autonomous module. 2. The magnetostrictive level gauge according to claim 1, characterized in that it has an autonomous power supply, a digital storage circuit for the measurement results, a radio modem and an antenna.

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