CH627840A5 - Method and device for monitoring the position of gas/liquid and liquid/liquid interfaces of media in a container - Google Patents

Description

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PATENT CLAIMS

1. A method for checking the position of separating surfaces of the media gas-liquid or liquid-liquid in a container constructed from single-layer walls, wherein an acoustic wave is generated and is supplied to the container through a sound-conducting medium which contacts the container wall at a first point and wherein a sound wave passing through this container and a further sound-conducting medium, which touches the container wall at a second point, is received for evaluation, characterized in that the direction of propagation of the acoustic wave (2) in the sound-conducting medium (3) is included the wall (4) of the container (5) encloses an acute angle, by means of this wave (2) at the corresponding first location in the container wall (4) sound waves (10) are excited, which pass through the wall (4) the direction of the acoustic wave (2) generated in the sound-conducting medium (3) and its entry angle (9) into the wall (4) given propagation direction plant, the entry angle 0 being chosen such that the velocity component of the acoustic wave (2) along the wall (4) is equal to the propagation speed of the sound waves (10) in this wall, and the amplitude of the acoustic wave (13), which is obtained at the second point from the sound wave (10) transmitted via the wall (4), is used as information about the position of the separating surface (8).

2. Apparatus for carrying out the method according to claim 1, which contains an electroacoustic transducer connected to an electrical generator (14) as a transmitter (1) for acoustic waves (2), an identical transducer as in the direction of propagation of said wave (2) Receiver (12) for acoustic waves is arranged, which, together with the transmitter (1), is coupled to the wall (4) of the container (5) by means of a sound conductor (3, 11), the contact surfaces (19) of which the container wall ( 4) and their effective areas (18) each touch the effective area of the transmitter (1) or the receiver (12), the electrical signals coming from the receiver (12) passing through an amplifier (15) and finally a measuring device (17) for the amplitude of these electrical signals, characterized in that the contact surface (19) and the effective surface (18) of each sound conductor (3, 11) form an angle 0 to one another, which defines the relationship:

whose damping when passing through the wall section is different from the damping of the first wave, the position of the separating surface of the media being determined from the amplitude ratio of the first and second waves.

5. The method according to claim 4, characterized in that said section of the container wall is periodically excited by an acoustic shock wave, the spectrum of which is at least the frequency range of the mechanical natural vibrations of the container wall at the various positions io of the separating surface of the media in relation to the excited wall section comprises, in addition the frequency of the received acoustic shock wave being determined, in order to then further assess the type of liquid when the separating surface of the media is located above or below the excited section 15 of the container wall.

6. The method according to claim 4, characterized in that said section of the container wall is periodically excited by an acoustic shock wave, the relative spectral width (Af / f) equal to or greater than the relative thickness-Än-

20 change of the excited section of the container wall (Ad / d) is selected.

7. The device according to claim 2, characterized in that with a variable cross-section of the wall (4) of the container (5), the sound conductors (3, 11) each have two parts (22, 23),

25 whose materials differ by the propagation speed of the acoustic wave (2,13), and which have a circular cylindrical contact surface (24), the axis of the cylinder surface perpendicularly intersecting the central axis of the electroacoustic transducer (1) or of the receiver (12) , 30 where the radius of the interface (24) is from the relationship:

Rér c <+ c *.

CH -t-Cc

C.L C. 5

c "-c2

A dg ö

35

6 = arcs / n (SjL)

fulfilled, where C3 is the propagation speed of the acoustic wave (2,13) in the sound conductors (3,11), and C is the propagation speed in the wall (4) of the container (5).

3. The method according to claim 1, characterized in that with a variable cross-section of the wall (4) of the container, a section of the latter is excited by a diverging or converging acoustic wave (2), the maximum entry angle 0! and the minimum entry angle 02 of this wave according to the relationship:

is determined with C1; C2 the maximum or minimum propagation speed of the sound wave (10) on the section (9) of the wall (4) of the container (5) excited by the acoustic wave (2);

40 C4, C5 the propagation speeds of the acoustic wave (2) or the wave (13) in the individual parts (22, 23) of the sound conductor (3, 11) and

A is the diameter of the effective surface (18) of the sound conductor (3), (11) in the plane determined by the direction of propagation of the excited 45 sound wave (10) and a normal to the surface (18), which is a divergence or convergence the acoustic wave (2) and the wave (13) guaranteed.

8. The device according to claim 2, characterized in that with a variable cross-section of the wall (4) of the container-50 ter (5), the sound conductor (3.11) have an effective surface (18) which is cylindrical with a radius of curvature R. after the relationship:

55

Re:

.2 (c4-C *)

A cta ©

sin © -1 sin

£ ± ^ 3.

can be selected, where 0l5 02 is formed by the direction of propagation of these waves and a normal to the container wall (4) at the corresponding point, and Cj, C2 is the corresponding maximum or minimum propagation speed of the sound waves along the container wall (4).

4. The method according to claim 1, characterized in that a further sound wave is generated in said section of the container wall by a second transducer (33),

where Q, Q is the maximum or minimum speed of propagation of the sound wave (10) on the section (9) of the wall (4) of the container (5) excited by the acoustic wave (2); and A is the diameter of the effective surface (18) of the sound conductor (3, 11) in the plane determined by the direction of propagation of the excited sound wave (10) and a normal to the «surface (18); and wherein the transmitter (1) for the acoustic wave (2) and the receiver (12) for the wave (13) have effective areas which correspond to the shape of the effective areas (18) of the sound conductors (3, 11)

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are adjusted, which ensures divergence or convergence of the acoustic wave (2) and the wave (13).

9. The device according to claim 2, characterized in that in the case of a variable cross-section of the wall (4) of the container (5), the diameter A of the effective surface (18) of the sound conductor (3.11) in a surface normal to this effective surface ( 18) and the direction of propagation of the sound waves (10) generated in the wall (4) of the container (5) according to the relationship:

is sufficient, Ht and H2 being the distances between the centers of the effective main surfaces (18, 32) and the contact surface (19) of the sound conductors (3, 11).

12. The device according to claim 8, characterized in that for the double excitation of the section (9) of the wall (4) of the container (5) by the acoustic wave (34) the sound conductors (3, 11) have a reflective surface (39) , which is arranged at an angle β to its effective surface (18), which has the relationship:

A éz k-lC <+ Ca

Cyf - CZ

.7 ^ djQ

is chosen

Q, C2 denote the maximum or minimum propagation speed of the sound wave (10) on the section (9) of the wall (4) of the container (5) excited by the acoustic wave (2),

K is a factor which is determined by the shape of the effective area (18) of the sound conductor (3, 11) and

X is the wavelength of the acoustic wave (2) in the sound conductors (3.11) and the minimum distance Hmin from the effective surface (18) to the contact surface (19) of the sound conductor (3.11) of the condition:

* Un> -

cos B

is sufficient, which ensures divergence of the acoustic wave (2).

10. The device according to claim 8 or 9, for performing the method according to claim 4, characterized in that with a double excitation of the section (9) of the wall (4) of the container (5) by the acoustic wave (2) the sound conductor ( 3.11) have an additional effective surface (32) which is inclined at an angle y to the contact surface (19), which corresponds to the relationship:

is sufficient, where C6 is the propagation speed of the second sound wave (38) excited on said section (9) of the wall (4) of the container (5), and it is an additional transmitter (33) for an acoustic wave (34) and an additional receiver (35) for a shaft (36), which are arranged on the additional effective surfaces (32) of the corresponding sound conductors (3), (11), the additional transmitter (33) together with the main transmitter (1) being connected to the Generator (14) for electrical vibrations is connected, and a series circuit comprising an additional amplifier (37) for electrical signals connected to the additional receiver (35), a circuit arrangement (29) for an electrical reference signal and a comparison unit (30) for an electrical one Measurement signal and the reference signal and a signal shaper (31) for the electrical measurement signal, the input to the output of the main amplifier (15) and the output to the other input of the comparison unit (3 0) is connected, the electrical coupling of the main amplifier (15) to a recording device (17) for the amplitude of the electrical signals via signal formers (31) and the comparison unit (30).

11. The device according to claim 10, characterized in that the distance E between the projections of the centers of the effective main surfaces (18) of the two transmitters (1, 33) on the contact surface (19) of the sound conductor (3, 11) of the relationship:

E = ft, ~ t% 6 - H.

ß - ÜL - (O - anzstn (Sb) \

C. £,

is sufficient, C6 being the propagation speed of the second sound wave (38) excited on said section (9) of the wall (4) of the container (5) and the device being a series circuit comprising a first gate (42) for electrical signals, the input of which is coupled to the output of the amplifier (15), has a signal former (31) for an electrical measurement signal and a comparison unit (30) and has a circuit arrangement (29) for an electrical reference signal, the output of which is connected to the other input of the comparison unit (30) is coupled, and further a second gate (43) for electrical signals, the output of which is connected to the input of the circuit arrangement (29) and the input of which is connected to the output of the aforementioned amplifier (15), and a circuit (44) for gate pulses, the outputs of which are connected to the controlled inputs of the gates (42, 43), and that as a generator (14) for electrical vibrations, a generator for pulse amplitudes The modulated vibrations are used, at the output of which the input of the circuit (44) for gate pulses is coupled, the electrical connection of the amplifier (15) to the recording device (17) via said series circuit from the first gate (42). , the signal former (31) and the comparison unit (30). 35 13. Device according to claims 7, 8 and 9, characterized in that when the section (9) of the wall (4) of the container (5) is excited by an acoustic shock wave, the generator (14) for electrical vibrations has a signal former ( 45) for electrical pulses with a broad spectrum and ■ »o contains a power amplifier (46) for electrical pulses connected to the latter, the output of which is connected to the transmitter (1) for the acoustic wave (2), and the device includes a signal shaper (31 ) for an electrical measurement signal, the input of which is connected to the output of the amplifier (15) for electrical signals, the comparison unit (30), the input of which is coupled to the output of the signal shaper (31), the circuit arrangement (29) for an electrical reference signal, the input of which is coupled to the power amplifier (46) and the output of which is coupled to the other input of the comparison unit (30), a frequency measuring unit (47) whose input is connected to the Au is connected to the amplifier (15), the electrical connection of the amplifier (15) to the recording device (17) for the amplitude of the electrical signals through a series circuit of said Si-55 signal former (31) and said comparison unit (30 ) is formed for an electrical measurement and a reference signal.

14. The device according to claim 12, characterized in that the sound conductor (3, 11) made of a material from the group: quartz, porcelain, silicate glass, lead, tin and lead-tin.

60 alloys with acoustic impedance in a range from 0.3 to 1.7 of the acoustic impedance of the radiator (1) for the acoustic wave (2) or the receiver (12) for the acoustic wave (13) are executed.

15. Device according to claims 9, 11 and 12,

65 characterized in that the sound conductors (3), (11) are made from a substance from the group: aqueous alcoholic solutions, alkaline solutions, acid solutions and salt solutions of inorganic acids, which are at least approximately a square

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4th

table dependency of the speed of propagation of the acute interface of the media is recorded. Have the static wave (2,34) by temperature. In addition to the floating body, the device for performing this method contains a measuring arrangement for detecting the

Displacement of the float. For this, e.g. an in-

5 induction coil and a sensor for a change in the electroma- The present invention relates to a method for the convergent field of the coil, which is caused by the displacement of the position of separating surfaces of the media, the gas-liquid of the float with respect to the coil, and liquid -Liquids in from single-layer walls- The method and the device in question, however, have built containers, whereby an acoustic wave generates and a low reliability and accuracy in the control by a sound-conducting medium, which holds a container wall on the parting surface layer of viscous media touched on, as a result of the first point, the container is fed and where- sticking of the float in one of the two media to one of these containers and another sound-conducting measurement- as well as in the control of the separating surface of the media gas-liquid, which the Container wall touched at a second point, liquid in the case of the front the presence of a dense foam on a continuous sound wave is received for evaluation, the surface of the liquid that covers the floating body like a corresponding device. 15 draws.

Such methods can be used in automatic control systems for hydrometallurgical processing processes in the egg Media (for example, the magazine "Devices and automation-contactless control of the interface of various means of measurement", Moscow, 1962, N. 7, pp. 439 to 440) known.

are used in single-layer containers. This procedure consists in the fact that within the container

A control of the position of interfaces of media ters a sensing element in the form of two plates (or rods) with the use of a difference between certain egg and a free gap and the capacity of the sensing properties of these media. ment is measured by the dielectric constant of the

The production processes to be monitored can depend on the medium located in the gap mentioned, the position of the media interface to be checked, which determines certain media malfunctions, being identified according to the various properties of this capacity which are subject to fluctuations. In addition to the capacitive sensing element, the device for carrying out and difficulties in controlling the position of the separating surface contains gas-liquid and liquid-liquid. A display device for changing the capacity of the relevant properties of this type includes in a series of industrial elements which, when the productions to be controlled are shifted, variable density of liquids, variable pressure separating surface of the media in relation to these takes place.

ke and viscosity, variable dielectric constant, di- The disadvantage of the described method and the constant

the liquid with air bubbles, thick foam layer control device for the interface layer of the media, the low-consistency on the surface of the liquid, suspect reliability, which due to the fluctuations in the dielectric composition's inconsistent composition within the liquid 35 fresh constant of the media and a change in the gap, among others in the sensing element and consequently its capacity due to

The control procedures and devices for the La presence of suspension particles are caused by the separation of gas-liquid and liquid-liquid interfaces. There is also an impedance of the first group, which comes down to the influences of the process and a control device for the Interface of the aforementioned fluctuating factors on the secure media (see, for example, US Pat. No. 3,246,546).

control and accuracy to a minimum. The method mentioned consists in measuring the electrical

put. Other requirements include sensitivity, see impedance of the control housed inside the container, safety for the operating personnel, simple ultrasound transmitters, the value of which changes as the level passes through the separation of the construction of the device and no high trade area of the media on which the station prizes. 45 is arranged. The facility for carrying out this

To control the position of the separating surface of media, an ultrasound transmitter, a generator for electrical vibrations coupled to it according to its physical nature and a device that implements and implements it, are used to display the change of the media electrical impedance of the Senn divided into two groups according to technological features.

are: probe methods and non-contact methods and set-up. The method and the corresponding equipment. In the first of these groups, sensing elements, due to a low dynamic range for the control, by means of which information about the separation area to be controlled, the separation area of the media gas-liquid with regard to the area of the media are taken, into the interior of the container density of the liquid media and introduced a not sufficiently high state in which the media in question are located, reliability in checking the interface of two liquid and in contact with these media. In the second group 55 labeled media. The latter phenomenon is due to the fact that the sensing elements are outside of the control - a slight difference between the electrical impedances of the container and are not due to any direct influence of the transmitter, which is subjected to liquids by the media whose interface is to be controlled. is damped, the interface of which is to be checked.

It is a float group belonging to the first group. Common disadvantage of all three of the above-

drive and a control device for the position of the separating surfaces. Process and installation of the first group is the Notehe (see eg the book by DI Agejkin, EN Kostina and NN maneuverability to arrange sensing elements within the container, Kusnezowa "transmitter for control and regulation", Publishing house “What a setting of the respective process during assembly, schinostrojenije”, 1965) known. This procedure requires maintenance or repair of the facility.

by making a hermetic, hollow, or loan in the container. In addition, the lifespan and low-density float housings greatly reduce the reliability of these devices if the container is not wetted by the liquid in question and is filled with chemically aggressive liquids.

experiences a buoyancy in the lower medium. The vertical connection of these disadvantages are the second to the above

Movement of this body, through the location of which the procedures and facilities belonging to the control group are free.

5

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It is a radioisotope that falls into the second group - a strong increase in the power of the generator for electric driving and a control device for the separating surface of the vibrations with corresponding complication

Media (see e.g. the book by A.K. Makarow and W.M. Swerd- and price increase of the facility is necessary,

lin «Automatic level control devices», publisher, In addition, the presence of gas bubbles

"Energija", 1966). 5 sen and solid particles in the liquid media within the

This method consists in the determination of the sub-container a considerable spread of the spreading of the absorption of the radioactive radiation which affects the sound wave with an increase in the container mass of the container in an exponential amplitude decrease of the reception wave coinciding with its axis. This

Direction penetrates through media in the container, the separation of which causes large errors and makes the practical evaluation of the area to be checked. The facility to carry out the procedure in question and the facility in a series of this procedure contains on opposite sides of cases impossible.

Sources arranged on its outer surface and the object of the present invention is a receiver for radioactive radiation and a measuring device coupled to the receiver control method for the separating surface position of the media gas. Liquid and liquid-liquid in from single layer

The disadvantages of this method and the development of the control-walled containers and the device for the separating surface of the media include the fact that the accuracy of the implementation of this method has to be low, in terms of simplicity, constructive complexity and high cost of use of a container wall section as information

direction and a possible danger to the operating function source for the position of the medium to be controlled or personnel due to the radiation. the separating surface of the media in the area of the relevant

There is also a further control method for the separation section and the execution of the sound conductors, a surface of the media gas-liquid and liquid-liquid in excitation of the mentioned section of the container wall.

Containers built from single-layer walls (see e.g. the shape that allows to control the interface surface)

U.S. Patent No. 3 213 438). media in a wide range of material,

This method boils down to the fact that an acoustic state and properties can be carried out independently, the wave generated by a sound-conducting medium, the 25 control accuracy increase, and the construction of one wall of the container device made of single-layer walls and its operation lowering the price and ters in a first place, introduces into this container, simplifying the maintenance costs.

one this container and another sound-conducting medium, this task is achieved by the method according to patent

that solved the wall of the single-layer container on a second saying 1, and the inventive device for

Touched point, receiving continuous sound wave and from the execution of the method is defined in claim 2.

Amplitude of the sound wave passed through on the separation. The described in more detail with reference to the drawings. Show it:

Changes in amplitude are here with a difference in Fig. 1, the overall view of a single-layer container

Passage of the sound wave through the media within the transmitter or receiver arranged on its side surface

attributed to halters, the interface in this process 35 ger for a sound wave;

is checked. Figure 2 shows a cross section through the container in plan view.

It is also a control device for the separating surfaces; FIG. 3 shows a longitudinal section through the container with the gas-liquid and liquid-liquid media arranged in this on a control device;

single-layer containers known, one to a generator; FIG. 4 shows a section of the container wall with the transmitter connected thereon for electrical vibrations for a transmitter arranged;

contains acoustic wave, wherein in the direction of propagation of FIG. 5 is a side view of FIG. 4;

6, a further embodiment of the transmitter arrangement is set up.

is that together with the transmitter on the wall of the stratification;

gene container is arranged with the help of a sound conductor, FIG. 7 is a side view of FIG. 6;

The contact surface in each case the container wall and its effective surface.

me area the effective area of the transmitter for the wave ac- tion;

static vibrations or the receiver for the sound wave Fig. 9 is a side view of Fig. 8;

touches, whose output to a series circuit from a Fig. 10, a variant of Fig. 3, with a reference signal

Amplifier that works in the electrical circuit arriving from the output of the receiver;

electrical signals and a measuring device for the amplitude, so FIG. 11 shows a variant of FIG. 10;

electrical signals are connected, from which a further embodiment variant of FIG. 10 is shown in FIG. 12;

Separation surface of the media gas-liquid or liquid-flow. FIG. 13 shows a further variant of FIG.

liquid is closed. the acoustic wave is stimulated;

14-20 different variants of the arrangement of the transmitter media gas-liquid, in particular liquid-liquid, on the container wall with the aid of a sound conductor.

speed, and the device for its implementation does not permit control when used in many industrial productions, for example the present control device for the interfaces in processing, hydrometallurgical and a number of layers of the media gas-liquid and liquid-liquid in chemical productions With the required single-layer containers, a transmitter 1 (FIGS. 1 and 2) contains accuracy to be carried out, which results in considerable errors, 60 for an acoustic wave 2, which by means of a sound conductor 3 increases structural complication and increases the price of the equipment Wall 4 of a prayer made up of single-layer walls. holder 5 is coupled, in which there is a gaseous and a This is due to the fact that the diameters of the containers of liquid medium 6 and 7 are located with a separating surface 8. 8 to 10 meters, which is a strong scattering of the sound. The transmitter 1 is arranged on a section 9 in such a way with a strong decrease in amplitude in the reception area 65 net that in the wall 4 (FIG. 2) by the acoustic wave 2 that caused. In order to reduce the scatter, a transmitter requires a sound wave 10 to be excited, which propagates in the predetermined magnification of the dimensions of the radiating surface of the sensor.

ders and the frequency of the emitted wave, which in turn The device also has a means of a sound conductor

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6

11 on the section 9 in the direction of propagation of the sound wave 10 receiver 12 set up for this.

At the transmitter 1 is a generator 14 (Fig. 3) for electrical vibrations and at the receiver 12 a series circuit of an amplifier 15 for electrical signals, the amplitude of which depends on the type of a medium 16 touching the section 9 of the wall 4, that is located above or below the separating surface 8 (FIG. 1), and a measuring device 17 (FIG. 3) is switched on for the amplitude of these signals.

So that the speed of the track of the acoustic wave 2 fed to the container 5 along the wall 4 is approximately equal to the speed of propagation of the sound waves 10 in this wall, the effective area 18 is the sound conductors 3 and 11 on which the transmitter 1 and the receiver 12 respectively are arranged, and the contact surface 19 of these sound conductors 3 and 11 touching the wall 4 are arranged at an angle 0 to one another, which results from the relationship:

Shaft can be reached with the entry angle according to the relationship:

are approx

^ _

sin 6 *

(z)

e =

arcs / n (* ~ 3 1 C

;

L4)

is determined (critical angle of total reflection), C3 being the speed of propagation of sound waves 2.13 in sound conductors 3.11 and

C are the propagation speed of the sound waves in the wall 4.

The sound conductors 3.11 are made of a material whose propagation speed of the sound wave 2.12 is lower than that of the wave 10 in the wall 4.

The sound conductor 3.11 can be made of the same or different materials. In the latter case, the angles 0 in the sound conductors 3 and 11, as follows from the relationship (1), will be different. In all of the following variants, the design of the two sound conductors 3, 11 made of the same material is assumed.

In the variant described, the sound conductors 3.11 are made of plexiglass; they can also consist of containers filled with a 16% aqueous solution of ethyl alcohol.

The sound conductors 3.11 are arranged with the contact surfaces 19 on the wall 4 of the container 5 on the section 9 to be excited with the aid of a flange 20 which, in the variant described, is attached to stud bolts (not shown) previously welded to the container 5, which protrude through mounting holes in flange 20. As another variant, it is possible to glue the flange 20 to the wall 4 of the container 5.

Part of the surface of the sound conductor 3, 11 is covered with a layer 21 made of a material which improves the coupling of sound waves, a mixture of epoxy resin provided with tungsten powder and a polymerization activator.

A piezoelectric element (see e.g. U.S. Patent No. 2,931,223) is used as the transmitter 1 for an acoustic wave. The receiver 12 has a construction analogous to that of the transmitter 1. The generator 14 is provided with frequency stabilization by quartz control for continuous wave operation. The measuring device 17 for the amplitude of the electrical signals is a recording device of known construction (see, for example, US Pat. No. 3,345,861). If digital signaling about the presence or absence of the interface of the media to be checked is required at the predetermined level, the measuring device 17 can be designed as a relay unit.

The reduction in the influence of a variable cross-section of the wall 4 of the container 5 on the control of the separating surface 8 (FIG. 1) of the media 6 and 7 can be selected by exciting the section 9 of the wall 4 of the single-layer container 5 by means of a diverging or converging acoustic ,

where 0j, 02 are the maximum or minimum entry angles of the acoustic wave 2 (FIG. 4), the angles io between the direction of propagation and the normal to the wall 4 of the container 5 being designated, Cb C2 the maximum or minimum rate of propagation of the wave on the section of the wall that is in contact with the sound conductor.

15 Here, for each value of the variable cross-section of the wall 4 in the range dt to d2, there is an entry angle which fulfills the equation (1), which ensures the maintenance of an optimal excitation of the acoustic whiff in the wall.

To introduce a converging or diverging wave in the angular range from 0t to 02, each of the sound conductors 3 and 11 is produced from two parts 22 and 23, the materials of which are characterized by the propagation speeds of the acoustic waves 2,13 (FIG. 2). differentiate. The parts 22 and 23 (FIG. 4) have a circular cylindrical contact surface 24 with an axis which lies in a plane with the central axis of the transmitter 1 and the receiver 12 (FIG. 3) and perpendicular to this central axis. Here, the radius of the cylindrical surfaces 24 (FIG. 4) is determined according to the relationship:

30th

Re

C4 + Ctz. CH + cs

I A.. dg G it)

cH-c2

selected, where C4, C5 the propagation velocities of the acoustic wave in parts 22 and 23 and 35 Ä the expansion of the effective surface 18 of the sound conductor 3.11 in a direction through the trace of the normal plane extending in the direction of propagation to the wall 4 on the Area 18 is determined

Here, the central beam 25 (FIG. 4) of the acoustic wave 2 passes without refraction through the contact surface 24 and into the wall 4 at an angle to the normal which is equal to the angle of inclination 0 of the effective surface 18 of the part 22 of the sound conductor 3, while the outermost rays 26 and 27 are broken on this surface 24 and enter the wall 4 at the 45 angles 0j and 02 greater or less than the entry angle 0 of the central ray 25.

To eliminate interference caused by the occurrence of multiple reflections of the acoustic wave 2, 13, part of the sound conductor 3, 11, as in the variant shown in FIG. 3 50, has a layer 21 made of a layer that absorbs the sound waves Material covered.

The reduction in the influence of the different wall thickness 4 of the container 5 is also achieved in that the effective surface 18 of the sound conductor 3 (FIG. 6) of the transmitter 1 55 and the sound conductor 11 (FIG. 3) of the receiver 12 are cylindrical with a radius of curvature R. (Fig. 6), which results from the relationship:

60

CA ~ Cz + C2

0-)

is determined.

The transmitter 1 and the receiver 12 (FIG. 3) in the form of a part of a hollow cylinder with an inner radius of curvature are equal to the radius R (FIG. 6) of the effective surface 18 (FIG. 7) of the sound conductors 3 and 33 ( 3), and the converging beam is introduced into the wall 4 in an angular range from 0j (FIG. 6) to 02, which is an optimal

7

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Male excitation of the sound wave 10 of the section of the wall 4 guaranteed at thicknesses from dt to d2.

The weakening of the influence of the different thickness of the wall 4 of the container 5 can also be achieved according to FIG. 8 by the length A of the effective surface 18 of the sound conductor 3.11 (FIG. 3) from the relationship:

A é: K

Cjf + C 3. CA - C-2.

? id $ Q (S)

is determined, where K is a factor which is determined by the shape of the effective area 18 of the sound conductors 3.11 (0.86 for a round and 0.7 for a rectangular effective area) (numerical values are from analytical formulas for the directional diagrams of the radiators having the aforementioned shapes of the radiation surface);

X the length of the wave 2.13 acoustic vibrations in the sound conductors 3.11 and

0 are the angle of inclination of the effective surface 18 of the sound conductors 3, 11.

The minimum distance Hmin (FIG. 9) from the effective surface 18 to the contact surface 19 of the sound conductors 3, 11 (FIG. 3) is determined from the relationship:

the above-mentioned transmitter 1 (Fig. 11) for the acoustic wave 2, which is connected to the generator 14 for electrical vibrations and arranged on the sound conductor 3, and the receiver 12 for the sound wave 13, which is connected to the amplifier 15 and on the sound conductor 11 is arrayed. The electrical circuit of the variant of the device described also contains a measuring device 17, a circuit arrangement 29 for an electrical reference signal, a comparison unit 30 and a signal shaper 31 for the electrical measurement signal.

In the variant of the device described, the sound conductors 3 and 11 have an additional effective surface 32, which extends at an angle y to the contact surface 19, which results from the relationship:

T

arcs »r>

fr)

20th

Al..cose

(6)

calculated.

The flat front 28 (FIG. 8) of the acoustic wave 2, which is retained over the distance B, is converted to a partially spherical front with divergent rays (near field), the entry angle of which for the wall, when approaching 30 the contact surface 19 is in a range from the maximum angle 0 to the minimum angle 02. These angles ensure the excitation of the mechanical vibrations 10 in the predetermined thickness range from di to d2 of the wall 4 of the container 5.

To eliminate the influence of fluctuations in the amplitude of the acoustic wave 2 excited in the sound conductor 3 on the measurement signal emitted by the receiver transducer, the latter is compared with an electrical reference signal 40 from the generator 14 (FIG. 12) via a circuit arrangement 29, a comparison unit 30 is supplied. The latter is also supplied with the electrical measurement signal from the receiver 12 via an amplifier 15 and a signal shaper 31. The output of the comparison unit 30 is connected to the measurement signal 17, 45 at which, depending on the control task set, a signal arrives that is proportional to the difference or the ratio of the measurement signal to the electrical reference signal.

During operation of the device, it is possible that the conditions for the introduction of the acoustic wave 2 (FIG. 50 10) change via the contact surface 19 into the wall 4, which changes the amplitude of the sound wave 10 on the excited section 9 of the wall 4 of the Container 5 and consequently errors in the control of the separation surface 8 (Fig. 1) of the media can result. 55

To eliminate these errors on the mentioned section 9 of the wall 4 of the container 5, a secondary acoustic wave excites a further sound wave with an attenuation which is different from the attenuation of the sound wave excited by the primary wave. Here, the separating surface 8 60 of the media is assessed according to the amplitude ratio of the sound waves caused by the primary and secondary acoustic waves.

To realize a double excitation of sound waves in the wall 4 of the container 5 by an acoustic wave 65, two embodiment variants of the device shown in FIGS. 11 and 12 are proposed.

The device according to the first of these variants contains is determined, where C6 is the speed of propagation of the secondary excited sound wave on said section 9 of the wall 4 of the container.

As explained in the publication "Physical Accoustics, Principle and Methods", vol. 1, chapter "Methods and Devices", part a, 1964, Academspress, New York and London, and confirmed in chapter 2 by experimental results, the rate of reproduction depends in a wall along its surface both on the wall thickness and on the excitation frequency. With different excitation frequencies, which are caused by the different entry angles of the acoustic waves, different propagation speeds therefore occur for the primary and secondary sound waves. The same are also subject to different damping in the container wall, which is caused by the dissipation of part of their energy into the medium touching the inner surface of the wall. The fact that the damping of sound waves is generally frequency-dependent, e.g. from Gerthsen, Physik, 9th ed., 1966, p. 123.

In the device according to FIG. 11, an additional transmitter 33 for an acoustic wave 34 and an additional receiver 35 for a sound wave 36 are provided, which are arranged on the additional effective surfaces 32 of the corresponding sound conductors 3 and 33. Here, the additional transmitter 33 together with the main transmitter 1 is connected to the generator 14 for electrical vibrations. In the electrical circuit of the device, an additional amplifier 37 for electrical signals is also provided, which is coupled to the additional receiver 35 for a shaft 36, which has been transformed from sound waves 38 generated in the wall 4 by the shaft 34, which, as explained above, have an attenuation that is different from the attenuation of the primarily generated sound waves 10. The output of the amplifier 37 is connected to the input of the circuit arrangement 29 for an electrical reference signal, the output of which is coupled to the input of the comparison unit 30 for the electrical measurement signal and the reference signal. The output of the signal shaper 31 for the electrical measurement signal, the input of which is connected to the output of the amplifier 15, is connected to the other input of the comparison unit 30. The output of the comparison unit 30 is coupled to the measuring device 17.

In the embodiment variant of the device described, the distance E between the projections of the centers of the effective main and additional areas 18 and 32 of the two sound conductors 3 and 11 on their contact surface 19 is expedient according to the relationship:

H = H, - - 4 ■

(8th)

11, which immediately results from the geometry of the arrangement according to FIG. 11, where Hj and H2 represent the distances between

627 840

8th

see the centers of the effective main and additional surface 18 and 32 and the contact surface 19 of the sound conductors 3 and 11 are.

The presence of an additional sound transmission path (transmitter 35 for an acoustic wave 34 - sound wave 38 5 in the wall 4 - receiver 35 for an acoustic wave 36) and an electrical circuit for a reference signal (amplifier 37 - viewing arrangement 29) allows the control accuracy The presence of instabilities when introducing the acoustic wave 2 into the wall 4 via the 10 contact surface 19 of the sound conductor 3 and when receiving the wave 13 in the sound conductor 11 via the contact surface 19 thereof is substantially increased.

In the variant of the device shown in FIG. 12, the sound conductors 3 and 11 have a reflection surface 39 to ensure double excitation of the wall section 9 of the container 5 by the sound wave from the transmitter 1, which are arranged at an angle β to the effective surface 18 is that from the relationship:

) 20

L9)

<—6

is determined.

The additional generation of the sound wave 38 in the wall 25 4, which propagates there at the speed C6, is caused by the acoustic wave 34, which results from a wave 40 of the transmitter 1 after its reflection on the reflection surface 39. The reception of the additional wave 36 transformed from the additionally generated sound wave 38 takes place after 30 reflection on the reflection surface 39 in the sound conductor 11 and its transformation into a wave 41 by the same receiver 12 which receives the primary acoustic wave 13.

The electrical circuit of the described variant of the device contains a series circuit comprising a first 35 circuit 42 for electrical signals, the input of which is connected to the output of the amplifier 15 for electrical signals, the circuit arrangement 31 for an electrical measurement signal, and the comparison unit 30 for the electrical measurement - and a reference signal. In the circuit there is also a circuit arrangement 29 for the electrical reference signal, the output of which is connected to the input of the unit 30, and a second gate circuit 43 for electrical signals, the input of which is likewise connected to the output of the amplifier 15 and the output the input of the circuit arrangement 29 is coupled. The 45 electrical circuit also includes a control circuit 44 for generating the gate pulses, the outputs of which are connected to the control inputs of the gate circuits 42 and 43.

In the variant described, a generator 14 is provided for vibrations with pulse amplitude modulation (which have a duration of t in each modulation period), to the output of which the input of the control circuit 44 is connected. The gate circuits 42 and 43 are designed in a known manner as an amplifier with an additional controlled input for a gate pulse, which corresponds in time to the reception of a selected signal which occurs from the amplifier 15. The control circuit 44 is designed as a scan generator (see, for example, the book by I.N. Jermolow "Ultrasound Review Process", Moscow, Verlag MGI, 1966, pp. 118 to 119). 60

When checking the interface 8 (FIG. 1) of the media, which differ significantly in their physical properties, the resonance frequency of the wall vibrations (FIG. 2) on the excited section 9 of the wall 4 of the container 5 changes depending on the position thereof Partition surface 8, which changes the conditions for their excitation by the acoustic wave 2 and their amplitude and the amplitude of the electrical vibrations at the output of the receiver 12

decreased. All of this can cause considerable errors in the control of the interface layer 8 (FIG. 1) of the media.

To eliminate the influence of these phenomena, section 9 of wall 4 (FIG. 2) of container 5 is periodically excited by an acoustic shock wave 2, the spectrum of which comprises a frequency range that is greater than that in which the mechanical natural vibrations of wall 4 of the Container 5 are at different positions of the interface 8 (Fig. 1) of the media 6 and 7 opposite the vibrating section 9. The excitation of the sound waves 10 (FIG. 2) in the wall 4 is determined by the wave 2 in the natural frequency of the wall regardless of the position of the separating surface 8 (FIG. 1) and the type of medium 16 (FIG. 3) that touches the inner surface of the excited portion 9 of the wall 4 of the container 5. The frequency of the incoming acoustic shock wave 13 is additionally determined, and this frequency is used to determine the type of liquid at the position of the separating surface 8 (FIG. 1) of the media above and below the vibrating section 9 of the wall 4 according to the above (Fig. 2) of the container 5 closed.

In order to realize a periodic excitation of the section 9 of the wall 4 by the shock wave, the generator 14 (FIG. 13) in the electrical circuit of the described variant of the device contains a unit 45 for generating electrical pulses with a broad spectrum and a power amplifier 46 connected to it whose output is connected to the transmitter 1 for an acoustic wave 2. The electrical circuit comprises the signal former 31 for an electrical measurement signal, the input of which is coupled to the amplifier 15, the comparison unit 30 for the electrical measurement signal and the reference signal, the input of which is connected to the output of the former 31, the circuit arrangement 29 for an electrical reference signal whose input is coupled to the power amplifier 46 and the output to the input of the comparison unit 30. The electrical circuit also contains a frequency measuring unit 47, the input of which is connected to the output of the amplifier 15. Here, the output of the comparison unit 30 is connected to the measuring device 17.

In the variant described, the unit 45 for generating electrical pulses with a broad spectrum is designed in the form of a circuit for electrical video pulses according to the known arrangement of a blocking oscillator. The duration x0 of these video pulses is according to the relationship:

To = <? - 5 fi

—T

(40y

selected, where fQ is the average frequency of the pass band of transmitter 1 or receiver 12.

If a piezoelectric plate is present as an active element in the transmitter and receiver, the value f0 is the resonant oscillation frequency of this plate.

In the variant described, the power amplifier 46 is embodied in a known manner as an emitter follower.

When the cross section of the wall 4 in the excited section 9 of the container 5 changes, the frequency of the primarily excited mechanical vibrations 10 and of the secondary excited mechanical vibrations 38 (FIG. 11, 12) is different. This causes different conditions for their excitation and subsequent transformation into a sound wave and consequently sets their amplitude and the size of the electrical signals at the output of the receivers 12, 35 for the waves 13, 16, which have been transformed from the incoming sound waves 10, 38, down and causes significant errors in the control of the interface layer 8 (Fig. 1) of the media.

To reduce these errors, the section 9 of the wall 4 (FIG. 2) of the container 5 with an acoustic shock wave

9

627 840

periodically excited, their relative spectral width

Af equal to or greater than the relative change in the thickness of the vibrating section 9 of the wall 4 of the container 5:

_ 2 (i2 "£ t) ^ 2 (^ 4- ^ 2.) ^

h ^ + dZ

is selected, where Af = f2-fj is the absolute spectral width of the shock wave;

f2, fj the upper and lower limit frequency of the spectrum of the shock wave;

f3 = 0.5 (f! + f2) are the average frequency of the spectrum mentioned and dj, d2 are the maximum and minimum thickness of the wall 4 of the container 5.

In order to implement the relevant technical solution in the device shown in FIG. 13, the sound conductors 3.11 are made of fused quartz, porcelain, silicate glass, tin, lead, or lead-tin alloys with an acoustic impedance z, which is in the

Table 2

Factory-melting-porcelain-silicate-tin

Quartz lan glass fabric

Range between 0.3 and 1.7 of the acoustic impedance z, the radiator 1 and the receiver 12 moved for a sound wave.

The average values of the acoustic impedance z0 (dimension-106 kg / m2 s) of the piezoelectric emitters and receivers made from quartz with the x-shear surface, lead metaniobate, barium titanate and lead zirconate titanate are listed in Table 1.

10th

Table 1 Quartz with x-shear area

15.2

Lead metanobate

16

Barium titanate

30.2

Lead zirconate titanate

36.5

The average values of the acoustic impedance z (dimension 106 kg / m2 s) and the speed C3 (m / s) of the sound conductors 3.11 made from the materials mentioned are listed in Table 20.

lead

13

13.5

15

24.2 24.6

Lead-tin alloys,% 25 + 27 50 + 50 75 + 25

24.3

24.4

24.5

5570 5600 5500 3320 2160

3030

2740

2450

This makes it possible to significantly expand the spectrum for the acoustic wave and accordingly to reduce the errors caused by the variable cross section of the wall 4 of the container 5.

The change in temperature of the wall 4 of the container 5 causes a change in the temperature of the sound conductors 3.11 and accordingly the speed of propagation C3 of the acoustic wave 2.13. This leads to the violation of the conditions (1), (7) of the primary and secondary excitation (FIGS. 11, 12) in the wall 4 of the container 5 and, as a result, to the occurrence of additional temperature errors when checking the separating surface 8 (FIG. 1 ) the media.

The reduction of these errors is achieved by the design of the two sound conductors 3, 11, which are described below with reference to those in FIGS. 14 to 20 using the example of the sound conductor 3.

The shape of the sound conductor 3 shown in FIGS. 14 to 20 is similar to the shape of the sound conductor shown in FIGS. 3, 4, 6, 11 and 12.

The sound conductor 3 is, however, in the above-mentioned variants shown in FIGS. 14 to 20 based on aqueous alcoholic solutions of alkaline solutions, acid solutions, 35 or salt solutions of inorganic acids, which approximately have a quadratic dependence of the propagation speed C3 of the acoustic wave 2 on the Have temperature, and their respective concentration weight is selected such that the maximum value C3 max of the speed of propagation of the shaft 2 lies in the region of the average temperature t0 of the wall 4 of the container 5.

Table 3 below shows the values C3 max and t0 for water and a number of aqueous solutions of different media: sulfuric, nitric and hydrochloric acids 45 (H2S04, H2N03, HCl), caustic soda NaOH, ethyl alcohol

C2H5OH, zinc sulfate ZnS04, formic acid amide HCONH2 and acetic acid nitrile CH3CN with the weight concentration q are given, which have the above-mentioned dependence on the speed of propagation of the acoustic wave 2.

50

Table 3 Medium dissolved in water q,%

t0, ° C Csmax 'm / s medium dissolved in water q,%

t ° C

lOJ ^

c3 max. m / s h2o h2so4

0

74 1555

C2H5OH

33 30 1565

12.5 40 1580

16 20 1605

h2no3

20 50 1520

ZnSQ4

6.7 60 1630

HCl

NaOH

27 30 1525

12 40 1665

24 50 1530

HCONH,

30 30 1510

50 1760

CH, CN

12 30 1860

20 50 1565

36.5

30th

1575

10 50 1550

17 30 1545

The sound conductors 3 shown in FIGS. 14, 18, 20 consist of a solution 49 from a work selected from Table 3, consisting of a hollow housing 48 and an aqueous substance filling this, which has the aforementioned dependence on the propagation

627 840

10th

Speed of the acoustic wave 2 excited by the temperature wall 4 sound waves 10, which sits over the wall 4 in. A propagate from a material absorbing the sound waves in one direction, the layer 21 produced by the direction of propagation becomes the inner surface of the hollow housing 48 in the sound conductors 3 shown in FIGS. 14, 18 and 19 of the acoustic wave 2 and their entry angle 0.

The transmitter 1 is provided with a hermetic seal. In the constructive variant seal shown in FIGS. 3 to 20 at a predetermined angle in the housing 48 below the device, the angle 0 is brought between the acoustic one. Here, the effective area of the transmitter 1 is always pointed at the wave front direction 2 and the direction of propagation when an aqueous acid and alkaline solution is used as the excited sound wave 10. In the case of completely aqueous solution 49, it can be dull if the excited sound-wave non-absorbing coating (not shown in FIGS. 14 to 20) propagates io len 10 in a direction that is opposite to . As such a coating comes tetrafluoroethylene polymer runs in the directions indicated in FIGS. 3 to 20.

sat in question. When shaft 2 is oriented, the speed

In the sound conductor 3 shown in FIG. 15, which is similar to the C7 of the track of this wave on the wall 4 of the container 5 and not shown in FIG. 4, part of this sound is approximately equal to the propagation speed C of the sound waves conductor 3, on which the transmitter 1 is arranged, in the form of a 1510 on this wall:

an aqueous solution of a ^ selected from Table 3

Material 51 filled hollow housing 50 executed. The the C. ^. - 3 ~ CL (currently

Wall 4 of the container 5 contacting contact part of the sound conductor n 0

3 is made from a material selected from Table 2.

In the case of the sound conductor 3 shown in FIG. 17, which selects 20, C3 being the propagation speed of the acoustically similar to the sound conductor 3 shown in FIG. 4, see wave 2 in the sound conductor 3.

is the contact part contacting the wall 4 of the container 5? The setting of the required value of the speed of the sound conductor 3 consists of a value C selected from Table 3? the shaft 2, 13 on the wall is made by hollow housing 52 filled with the corresponding aqueous solution 53. The choice of the entry angle 0 and the material of the sound conductor is part of the sound conductor 3 on which the transmitter 1 is arranged, 25 ters 3. The Entry angle 0 of the shaft 2 on the wall 4 made of a material selected from Table 2. Container 4 corresponds to the angle of inclination of the effective surfaces

In the sound conductor 3 shown in FIG. 17, which is also surface 18 of the sound conductor 3, the wall conductor 4 of which is similar to the sound conductor 3 shown in FIG. 4, have the contact surface 19.

two parts of the sound conductor 3 separate, with an aqueous one. The excitation of the transmitter 1 is carried out by electrical continuous

Solution 51 or 53 filled housing 50 and 52, in which the 30 nuclear or pulsed amplitude-modulated vibrations, velocities of the sound wave differing from each other which are generated by the generator 14.

Have values C4 and C5. The two parts of the sound conductor 3 The sound waves 10 undergo an amplitude decrease, the degree of which separates a degree that can be determined from the relationship (3) from the acoustic one as a result of its propagation over the wall 4 of the container 5 through a sound-conducting sheath 54 Impedance of the medium 16 depends, which has the Mungradius R. As such a partition, an inner surface of the vibrating section 9 of the wall 4 can be stirred as part of a polymer made from tetrafluoroethylene. If this medium is a gas, the removal of the mini hollow cylinder with the radius of curvature R mentioned is minimal, if a liquid - at maximum. If, however, ner inner surface are used in the container. The thickness of the partition 5 is two liquids, so the damping of the me-54 is set in this case by an order of magnitude smaller than the mechanical vibrations greater for a liquid with a length of the acoustic wave 2. 40 rer acoustic impedance.

In the contact parts of the sound shown in FIGS. 16 and 17, when the sound wave 10 reaches the mounting location of the sound conductors 3, the inner surfaces of the hollow housing 52 are also reached with ter 11, it is partly transfor-into a layer 21 from a layer 21 in the sound wave Sound-absorbing material that is covered in the sound conductor 11 at an angle to the material. tact area 19 equal

The ones shown in Fig. 18,19 and 20 and those in Fig. 6,11 «^

and 12 reproduced variants of similar sound conductors 3 - 0

keep one selected with an aqueous solution 49 in analogy to the variants described above from table 3 i.e. normal to the effective area 18 on which the receiver 12

Material filled housing 48th is arranged, spreads. The latter converts the

All of the above-described embodiment variants of the incoming shaft 13 in electrical signals with an amplitude direction can be successfully used to determine the interface area proportional to the amplitude of the sound waves 10 at the location of the media liquid-liquid. Schalleiters 11 um. The electrical signals of the receiver 12 The control method for the interface position of the media reach the input of the amplifier 15. From its out-gas-liquid and liquid-liquid in a single-layer aisle, the amplified electrical signals, which run in containers in the variants described above, arrive The information about the degree of damping of the sound wave 10 in the direction is as follows. Section 9 of the wall 4 of the container 5 and accordingly

With the aid of the transmitter 1 (FIGS. 1, 2, 3) an acoustic medium is carried over the separating surface 8 (FIG. 1), into the measuring shaft 2, via which the wall 4 of the container 5 contacts 17 (Fig. 3). Depending on the amplitude of the switching conductor 3, containers 5 filled with two electrical signals strengthening a separating surface 8 pointing to the position of the interface 8 (FIG. 1) and 7 are filled with containers 5 (FIG 1) closed, this amplitude of that leads. The introduction of the wave 2 takes place on a section 9 of the sound wave 13 (FIG. 3) which is proportional to the sound waves 10 which propagate over the wall 4 of the tank 5 which is propagating at a predetermined level, on which the interface 8 has been lubricated by the present one.

direction should be set. Is the amplitude of the measured electrical signals

The front of the shaft 2 is before the introduction into the 65ximal, so the separating surface 8 (Fig. 1) of the media gas flow container in the sound conductor 3 is at an acute or obtuse angle below the section 9, it is minimal, it lies 0 (Fig. 3) to the wall 4 of the single-layer container just above it. When checking the interface 8, liquid-tet, and through this shaft 2 on the section 9 of the liquid, the cases considered relate to the liquid

11

627 840

the first of which has a lower acoustic impedance than the second.

A sudden change in the amplitude of the measured electrical signals testifies to the course of the interface 8 of the media at the level at which the vibrating section 9 of the wall 4 of the container 5 with the transmitter 1 and receiver 12 arranged thereon by means of a sound conductor 3 for a sound wave is located . This change in amplitude can be determined automatically by a recording device or a relay unit in the measuring device 17 (FIG. 3).

The control method described above for the interface surface position of the media gas-liquid and liquid-liquid is structurally simple and allows effective control with a constant cross section of the wall 4 of the container 5. A change in this cross section leads to a change in the propagation speed C of the sound waves 10 in the wall 4 and consequently destroys the equality between this and the speed C7 of the track of the introduced acoustic wave 2 on the wall. Furthermore, the amplitude of the sound waves 10 excited in the wall 4 and accordingly the amplitude of the electrical measurement signal decrease, which causes errors in the control.

The errors of the type mentioned can be reduced by using the control method implemented in the device shown in FIG. 3 for the separation surface of the media gas-liquid and liquid-liquid in conjunction with the variants of the switching conductors shown in FIGS. 4 to 9.

According to the first variant of the method, section 9 of wall 4 of single-layer container 5 is excited with a divergent or convergent wave 2. The maximum and minimum entry angle 0t or 02 of this shaft 2 is selected according to the relationship (2). There is an entry angle for each of the thicknesses of the wall 4 (FIG. 4) lying in the range from d 1 to d 2 and for the corresponding propagation speed C of the sound waves 10 in the range from C 1 to C2, which is in the range 0j to 02 and fulfills the condition (1) for an optimal excitation of the sound waves (10).

The formation of a divergent wave from the wave 2 of the radiator 1 in the angular range of 0! to 02 takes place by means of the cylindrical contact surface 24 of the two parts 22 and 23 of the sound conductor 3, which has a radius of curvature R. Here, the central beam 25 of the shaft 2 passes through this surface 24 without refraction and becomes at an angle 0 equal to the angle of inclination of the effective surface 18 of the sound conductor 3 introduced into the wall 4 opposite its contact surface 19. The side beams 26 and 27 of this wave 2 undergo refraction because they are incident on the interface 24 not normal to it, but at an angle e with respect to the normal, which is given by the relationship:

where C4, C5 - speed of propagation of the shaft 2 in the individual parts 22, 23 of the sound conductor 3. The rays 26 and 27 will be inserted into the wall 4 at the angles 0j and 02 resulting from the relationships:

Qi = Q - are sin (

2nd row

A Ct

2CS R

-)

10th

02 = e - «rcsW ^ I) + j)

surrender.

15 So that the maximum and minimum angle 0 [or 02 of the shaft corresponds to the required convergence or divergence of the shaft after refraction, the radius of curvature R of the cylindrical contact surface 24 of parts 22 and 23 in the two sound conductors 3 and 11 (FIG. 3 ) selected according to relationship (3) 20, which satisfies condition (2) and relationships (15) and (16). Fig. 4 shows an example of a divergent wave 2 when C4> C5. If C4 <C5, wave 2 converges.

The implementation of the first variant of the method described above, the method which eliminates errors associated with a reduction in the electrical information signal, is ensured by a rather complicated design of the sound conductors 3 and 11. A simpler construction of the sound conductors 3.11 has a different design, which is shown in FIGS. 6 and 7.

In this embodiment, the sound conductors 3.11 have a cylindrical effective surface 18, while the transmitter 1 and the receiver 12 (FIG. 3) are designed for a sound wave 13 with effective surfaces that correspond to the shape of the active surfaces 18 of the sound conductors Repeat 3.11, creating a divergence or convergence of wave 2.13. The divergence of the shaft 2 takes place with a concave effective surface 18 of the sound conductor 3 and the convergence (shown in FIG. 6) with a convex one. Here, the central beam 25 of the shaft 2 is introduced at an angle 0 (equal to the angle between the tan-40% to the center of the effective surface 18 and the contact surface 19 of the sound conductor 3). The side beams 26 and 27 of the shaft 2 are introduced into the wall at the angles 0] and 02:

45

a = e +

sin £ -

2 rows

(13)

50 Q2 =.

6

aresin / A \

\ 2R '

aresine (A) 2R '

(fì)

is determined

where A - length of the effective surface 18 of the sound conductor 3 (or of the transmitter 1 and, accordingly, of the receiver 12 (FIG. 3) in a sound waves 10 excited by the direction of propagation in the wall 4 of the container 5 and a normal going to this surface 18 Level is.

After the refraction on the cylindrical surface 24 (FIG. 4), the beams 26 and 27 in the second part 23 of the sound conductor 3 are planted at an angle 8j with respect to the normal K to this surface 24:

€ .a = arcsin away,

£ 5 Sin €

) -

macaws in x? r .. R /

'2C.R

and these angles are larger or smaller than the angle 0 by a value 8, which is determined by the relationship (13). 55 In order for the angles 0t and 02, which are defined by these relationships (17), (18), to meet the condition (2) of the required convergence or divergence of the shaft 2, the length A of the effective surfaces 18 of the sound conductor 3 (or of the transmitter 1 and, accordingly, of the receiver 12) and the 60 curvature radius R of the effective revenges 18 on the basis of the relationship (4).

The device shown in FIGS. 6 and 7 ensures a reduction of the above-mentioned errors in the control of the separating surface 8 (FIG. 1) of the media by a cylindrical design of the effective surface 18 of the sound conductors 3 and 11 (FIG. 3) , the radiator 1 and the receiver 12 without the wavelength of the acoustic wave 2 being subject to any different conditions.

627 840

12th

A simpler variant, however limited compared to the considered variants, with regard to the choice of the length X of the shaft 2 is the arrangement of the device with the sound conductor 3 shown in FIGS. 8 and 9.

In this variant of the device, the minimum distance Hmin from the effective surface 18 to the contact surface 19 of the sound conductor 3 is selected according to relationship (6) such that the beam path of the side beam 27 exceeds the extension B of the Fresnel zone in the sound field of the radiator 1, within which the shaft 2 has a flat front 28 of non-divergent rays. When leaving this zone, the flat front 28 of the shaft 2 is transformed into a partially spherical one with a divergent bundle of sound beams 26 and 27, the outer of which are inserted into the wall 4 at angles 0t and 02, the first of which is larger and the other the second is smaller than the entry angle 0 of the central beam 25.

If the distance from the boundary of the Fresnel zone is sufficient, the divergence angle of the shaft 2 is determined by the directional diagram of the transmitter 1, and the entire sound radiation energy is limited by this divergence angle, which has a value:

Q.— &? - A A arcs'in-l ^^}

i * v A

«3)

having,

where kj - factor that can be determined by the shape of the effective surface 18 of the sound conductor 3, for example equal to 1.22 for a round shape and 1 for a rectangular shape.

The angles 0j and 02 are expressed by the following expressions:

64 «Ô + 0.1 aresine.

Q2 -Q - 0.? arc sin)

ri

(2.0)

C2-Ü

certainly.

The solution of the system of equations (2), (20) and (21) specifies a relationship (5) between the length A of the effective surface 18 and the wavelength X, at which the required divergence of the wave 2 takes place, which optimally excites the Section 9 (FIG. 3) of the wall 4 of the container 5 secures in a range from Cx to Q of the propagation speeds of the sound waves 10.

The device shown in FIG. 3 and its variants with different constructions of the sound conductor 3 in FIGS. 4 to 9 have an electronic device which makes it possible to check only when there is little (temporal) amplitude fluctuation in the electrical vibrations of the generator 14 (FIG. 3) exercise by which the transmitter 1 is excited. Every change in the amplitude of the electrical vibrations of the generator 14 requires a periodic changeover of the measuring device 17 or a change in the amplification factor of the amplifier 15, which influences the performance and the stability of the control.

The performance and the stability of the control of the interface position of the media gas-liquid and liquid-liquid can be increased by using a device shown in FIG. 10.

In this variant of the device, an electrical reference signal is generated in analog or digital form from the electrical vibrations of the generator 14 by the circuit arrangement 29; in the same form, an electrical measurement signal is generated from the electrical signals of the amplifier 15 by means of the signal shaper 31 and is compared with the electrical reference signal in the comparison unit 30. The output signal of the comparison unit 30, which is proportional to the difference or the ratio of the signals to be compared, reaches the measuring device 17. The fact that the amplitude fluctuations of the electrical vibrations of the generator 14 have an equal effect on the value of the measuring and the reference signal the influence of the above-mentioned instability on the control results for the interface of the media is practically zero.

The device described in connection with the variants of the sound conductor according to FIGS. 4 to 9 works in the case of various amplitude fluctuations in the electrical vibrations of the generator 14 and changes in the speed C of the sound waves 10 of the excited section 9 of the wall 4 of the container 5 in the region from Q to effective. When changing the conditions for the introduction of the shaft 2 in 20, the wall 4 through the contact surface 19 of the sound conductor 3, which are possible both during stationary operation of the device and during a quick check of the separating surface 8 (FIG. 1) of the media, may change however, change the amplitude of the sound waves 10 (Fig. 10). The changes in the introductory conditions can be caused, for example, by inconsistency in the thickness of the contact lubricant between the contact surface 19 of the sound conductors 3 and 11 and the wall 4 of the container 5, unevenness on the surface of the wall 4 during the quick check and cracking, detachment and partially 30 destruction of the contact surface 19 of the sound conductors 3.11 with the wall 4 of the container 5 with stationary control of the separating surface of the media sticking together. The changes mentioned require a periodic changeover of the signal shaper 31 for the electrical measurement signal, whereby substantial errors can occur in the control of the interface of the media during the changeover period.

Errors of this kind can be reduced by using the control method for the interface of the Me-40 serving as the gas-liquid and liquid-liquid in the devices shown in FIGS. 11 and 12.

According to this control method for the separating surface of the media, additional acoustic waves 38 are excited on section 9 of the wall 4 of the container 5 by the acoustic wave 34, the attenuation of which is different from that of the acoustic waves 10 excited by the primary wave 45 2. Here, the change in the conditions for the introduction of waves 2 and 34 into wall 4, as well as the change in amplitude of the electrical vibrations of generator 14, cause the same changes in amplitude of the primary and the additionally excited 50 sound waves 10, 38. In analogy to this, the change in the parameters of the contact surface 19 in the sound conductor 11 brings about an equal change in the sound wave 13 transformed from the sound waves 10 primarily excited in the wall 4 and the 55 sound wave 36 transformed from the sound waves 38 additionally excited in the wall 4.

Thanks to these special features, it is possible to infer the separation surface 8 (FIG. 1) of the media 6 and 7 from the amplitude ratio of the sound waves 10 (FIGS. 11 and 12) and 38, which were caused 60 by the primary acoustic wave 2 and 34, This is independent of the changes in the conditions which are determined by the introduction of the shafts 2, 34 via the contact surface 19 in the sound conductor 3 and the transformation on the contact surface 19 of the sound conductor 11.

In the device shown in FIG. 11, the shaft 34 is introduced into 63 the wall 4 for the additional excitation of the sound waves 38 by an additional radiator 33. It is with its effective area, which is combined with the additional effective area 32 of the sound conductor 3, with respect to the contact area

13 627 840

19 oriented at an angle y, from which the equality part 40 of the acoustic wave of the transmitter 1 generates the reflection condition for the speed of the track of the wave 34 on the xions surface 39 of the sound conductor 3, which with respect to the effective wall and the speed of the mechanical floating surface 18 is inclined at an angle β which is chosen from the relationship 38 (7) which satisfies the requirements. The insertion relationships (7) and (9) as the shaft 34 into the wall 4 take place here under the 5 ^

called angle y. —— + y — 8

The sound wave 13 transformed in the sound conductor 11 from the primarily excited sound waves 10 spreads under which is determined. The other part of the acoustic wave 2 from the angle 0 with respect to the normal to the contact surface 19 and the transmitter 1 is introduced into the wall 4 at the angle 0 and reaches the main receiver 12 normally for its effective i0 and in addition to the primary excitation of the mechanical surface. The sound wave 36 transformed from the acoustic vibrations 10 additionally excited in the wall 4 in the wall 4 on the section g 38 is used in the sound. In the sound conductor 11, the primarily excited sounds 11 are transformed at an angle y with respect to the normal to its waves 10 into an acoustic main wave 13 which

Contact surface 19 and enters the additional receiver 35 at an angle 0 with respect to the normal to its normal to its effective area. 15 contact surface 19 spreads. The additionally excited sound

From the electrical waves 38 obtained via the main amplifier 15, trans-signals from the main receiver 12 are generated in the sound conductor 11 into a sound wave 36 in a sound wave 36, which signals form electrical signals (in digital or more analogous to the contact surface 19 in the direction of the reflection surface 39), the amplitude of which plants the amplitude of the primarily excited one. From the latter, the wave 36 is reflected and sound wave 10 is proportional, which arrives at the mounting location of the 20 in the form of additional sound wave 41 in the receiver sound conductor 11. The circuit arrangement 29 generates 12 normal to its effective area.

The additionally excited sound waves 38 have an Aus-trischen signals of the additional receiver 35 an electrical propagation speed C6 on the wall 4 which is different from the reference signal, the amplitude of the amplitude of the speed C of the primary excited sound waves 10 is separately excited sound wave 38 at the mounting location of the 25, as has already been explained (is proportional in the execution sound conductor 11. Here, the electrical example of the device shown in Fig. 12 is C6> C). With reference and measurement signal from the units 29 and 31 in the same way in a certain path of the sound waves 10 along the wall 4, mass influenced by the instabilities which therefore reach the contact, the acoustic primary and secondary waves 13, surfaces 19 of the sound conductor 3 when the waves 2 41 are introduced into the receiver 12 with a time shift At and 34 and the sound conductor 11 during the transformation of the 30 against one another, the duration x of the pulse-amplitude-modulated sound waves 10, 38 of the primary and secondary excitation-induced electrical vibrations of the generator 14, which occur on. As a result, the output signal of the comparison transmitter 1 arrive, significantly exceeds ch. As a result, the unit 30, which is obtained from the incoming electrical measurement, primary and secondary electrical signals of the reference signal, and the ratio of these signals to the receiver 12, whose amplitude is primarily proportional to the amplitudes and independent of the instabilities mentioned. 35 and secondary excited sound waves 10,38 are proportional,

That the sound waves 10, 38 of the primary and secondary are separated in time.

Excitation a different attenuation in the wall 4 of the The signals of the receiver 12 pass through the

Have container 5, which carries a portion of its amplifier 15 to the inputs of the gate circuits 42 rer energy into the inner surface of the vibrating section 43 and 43, at the control inputs of which control signals from the output 9 of this wall 4 is caused by the medium 16 the 40 of the control circuit 44 arrive. In this case, the impulse coming into the output signal of the comparison unit 30, a unique gate circuit 42, corresponds to the time course of the information about the position of the interface 8 (FIG. 1) of the main measurement signal and that coming into the unit 43 - the time line 6 and 7 in the container 5 to be checked, which is due to the course of the reference signal.

the measuring device 17 is determined. The electrical primary and secondary signals that are

The union of the lead-in zone for the primary and 45 circuits 42 and 43 are separated, get into the secondary shaft 2 and 34 on the contact surface 19 of the Schallei signal former 31 for an electrical measurement signal and in the switch 3 and the zones for the transformation the sound wave arrangement 29 for an electrical reference signal and who are given the primary and secondary excitation on the capacitor then to the inputs of the comparison unit 30, tactile surface 19 of the sound conductor 11 into the main acoustic wave. From the output of the latter, this becomes a clear one Informa-13 and the secondary shaft 36 are delivered to the measuring device 17 by the choice of the distance 50 over the separating surface of the media containment E to be checked between the projections of the center points.

The main and additional areas 18 and 32 on the con The control method described above for the tact area 19 and the heights H! and H2 the arrangement of this interface of the media in single-layer containers centered on the contact surface 19 in accordance with relationship (8) ensures control with high accuracy and stability. 55 in continuous operation. At the same time, the entire process

The device in question ensures, in the case of certain, errors that are reduced by the instability of the simplicity of the electronic device, the acoustic wave being created in the wall and the transformation effectively eliminating the influence of the instabilities mentioned in the Wall of the container of excited sound waves, however, there are changes over time in the transformation-specific contact surface of the sound conductor, on which the receiver arranges the transmitter, which is why the corresponding 60 is created. In the procedure described above, it can cause errors. but errors occur due to a change in natural frequency

These errors can be reduced by using the mechanical natural vibrations on the excited device described in the device shown in FIG. 12, the wall of the container cut at different positions with a transmitter 1, a receiver 12 and a complex separating surface of the media in this container evoked the electronic device realized process. Turn 65 here.

the additional shaft 34, which is inserted into the wall 4 at an angle, with which the secondary sound wave is added in this wall 4. This error allows the control method for the len 38 to be additionally excited by a reflection of a separating surface of the media gas-liquid and liquid -Flux

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Reduce liquid in single-layer containers, which is listed in Table 2. Such an embodiment of the device shown in FIG. 13 is realized. Sound conductors 3 and 11 cause an acoustic damping of the sensor. According to this method, the section 9 of the wall 4, the receiver 1 and the receiver 12 is periodically excited with an appropriate expansion of the container 5 by an acoustic shock wave 2 for the limits of the radiation and reception spectrum, whose spectrum has a frequency range that 5 an acoustic wave 2.13. The reduction in the size of the greater than the frequency range of the sound waves 10 of the wall 4 acoustic impedance of the sound conductors 3 and 11, which depends on that of the container 5 at different positions of the separating surface 8 (FIG. Material from which they are made, also results in a 1) of media 6 and 7 with respect to the vibrating section relative to the acoustic impedance of transmitter 1 and 9 (FIG. 13) of wall 4. Here, the spectral width is reduced to the transmitter 1 with the receiver 12. The type of mate-impulses having a broad spectrum from the inputs of the sound conductors 3, 11 and accordingly its impedance 45 acted upon, which pass through the power amplifier 46. (see Table 2) are set depending on the spectral width required according to These pulses have the shape of rectangular video pulses with the relationship (11), a duration xa defined by the relationship (10). As a result of the method described, the transmitter 1 emits a spectrum of the separating surface of the media and the type of liquid when ultrasonic vibrations are emitted, which all values of the flow of the separating surface of the liquids above or below of the changing frequencies of the sound wave 10 in the wall 4 in the case of a vibrating section of the container wall (in the case of the different positions of the interface 8 to be checked, the gas-liquid comprises - in the course of the separating surface above (FIG. 1) the media. this section) . However, when the temperature changes

The pulse signal of the receiver 12 has an amplitude and errors still occur during the control. The value of which is dependent on the position of the separating surface 8 20 to be checked essentially by the temperature dependence of the spreading (FIG. 1) of the media. In addition, the frequency of the wave of acoustic vibrations in f of the electrical vibrations depends on the type of section which determines the sound conductors.

9 of the medium 4 contacting the wall 4 of the container 5 (FIG.

13). 3 to 13 shown control devices for the interface

The frequency f mentioned is measured in the frequency measuring unit 25 position of the media gas-liquid and liquid-liquid-47 for electrical signals, at which the signal from speed when using the capacitor 12 shown in FIGS. 14 to 20 via the amplifier 15 is supplied, and the structures of the sound conductor are significantly reduced.

the type of liquid (the reduction in temperature errors is ensured, for example, by the value of its acoustic impedance, that the sound conductor 3, 11 is water-characterized on the basis of the measured frequency) with the position of the interface 8 (Fig. 1) of the media 30 gene alcoholic solutions, alkaline solutions, acid solutions above or below the vibrating section 9 of the wall solutions, or salt solutions of inorganic acids executed 4 (Fig. 13) of the container 5 assessed. where the dependence of the speed of propagation

From the pulse signals of the receiver 12, a measurement signal is generated in the speed C of the sound wave 2, 13 from the temperature t almost qua-signal former 31, the value of which is the amplitude:

tude of the pulse signals mentioned is proportional. In addition, 35

out is made from the at the output of the power amplifier 46 - £ _ £ r _ -14 \ z ~ j (2 z 1

video pulses taken using the circuit arrangement 3 3 M L '0) —5'

29 generates an electrical reference signal. The latter and that

The measurement signal reaches the comparison unit 30, the output of which, C3max, the maximum value of the propagation speed output signal, is information about the separation of the sound wave 2, 13 to be checked in an aqueous solution at t = t0. Surface 8 (Fig. 1) of the media supplies and by the measuring device 17 Here, the solution concentration q is selected such that (Fig. 13) is recorded. the maximum value C3rnax of the propagation speed in

The variant of the method described ensures a range of the mean temperature t0 of the wall 4 of the container 5, effectively reducing the influence of the frequency changes. As a result, the speed of the sound wave of the sound waves, which are caused by different positions of the separating surface of the media, which is very trolling in the sound conductor 3 in the working area for the temperatures t, has slight changes, which occur, for example, in the case of a temperature control and for additional control of the Type of liquid with door deviation from the mean value t0 by ± 20 ° C a value of constant cross-section of the vibrating wall section. Do not make more than 0.6%. This allows the con- nections to change considerably in cross-section of the vibrating troll accuracy for the interface of the media to wall sections within wide limits, which increase a frequency change.

of the mechanical vibrations in a wider range than The control method described above for the gas-liquid and liquid-flow effects when changing the position of the separating surface of the media in the container, in the control of the latter, errors occur. liquid in single-layer containers, which by means of the in Fig. 3 to

The reduction of these errors is realized by a control device, which ensures that the interface surface of the media gas-liquid 55 ensures a contactless, automatic control of the interface of the liquid and liquid, which is also ensured by means of media in containers in the Metallurgy, processing technology, Fig. 13 shown device is realized. in the petroleum, food and other industrial

According to this method, section 9 of wall 4 will branch.

of the container 5 by an acoustic shock wave 2 periodically. It has a number of advantages compared to the known ones, the relative spectral width of which according to relation (11) 60 methods and devices.

equal to or greater than the relative change in thickness of the vibrating

section 9 of the wall 4 of the container 5 is selected. it is possible to considerably reduce the errors in the control of the interface position of the die. This ensures that the switching conductors 3 and 11 media in containers made of quartz, porcelain, silicate glass, lead, tin or lead, which are built up from single-layer walls, are considerably reduced and the checking accuracy of tin Increase alloys with acoustic impedance in the range of 0.3 "and reliability.

up to 1.7 the acoustic impedance of the transmitter 1 and the Emp- First, the method completely closes the errors of the catcher 12 are executed for a sound wave. The concrete control of the interface gas-liquid and liquid-flow materials from which the sound conductors 3, 11 are made are liquid, caused by a diffraction divergence of the sound wave

are caused in media, the limit of which is controlled in the container, because there is no need to register the wave propagating in the media mentioned, while the scattering of the mechanical vibrations propagating in the container wall and to be registered according to the invention is very little effective and the Control speed practically not affected.

Secondly, the method described above makes it possible to completely eliminate the errors which are caused by a considerable spread of the sound wave propagating in liquid media, the interface of which is controlled. This is achieved in that in the present method asl parameters, according to which the separation surface of the media is assessed, the amplitude of the sound wave transformed from mechanical vibrations is selected, which propagate over the container wall, while the propagation of these vibrations from the

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Scattering of the sound wave in the liquid media filling the container to be checked is dependent.

In addition, the device for realizing the method described above has a significant design simplification by enabling the use of a radiator of smaller dimensions and a much less powerful generator for electrical vibrations. This is ensured by eliminating the need for an abrupt increase in power for the sound wave, which is the case with the known device for ensuring the passage of the sound wave through extensive industrial containers. This elimination is due to the fact that the reception of the acoustic information wave occurs through a receiver on the section which is practically at least an order of magnitude less from the cross-section of the container from the insertion section of the sound wave.

C.

5 sheets of drawings