FR2599503A1 - METHOD FOR MEASURING THE PARAMETERS OF THE SOLID PHASE OF A SUSPENSION AND DEVICE USING THE SAME - Google Patents

Abstract

THE INVENTION CONCERNS MEASURING TECHNIQUES USING ULTRA-SOUND WAVES. THE DEVICE WHICH IS THE OBJECT OF THE INVENTION IS CHARACTERIZED IN THAT IT CONTAINS, IN EACH MEASUREMENT CHANNEL I AND II, A LOGARITHMIC CONVERTER 28, 41 CONNECTED TO THE OUTPUT OF THE SIGNAL AMPLIFIER RECEIVED 26, 39, A SUBTRACTOR 47 WHICH HAS ITS INPUTS CONNECTED TO THE OUTPUTS OF THE LOGARITHMIC CONVERTERS OF THE TWO WAYS, AND A DIVIDER 48 WHOSE INPUTS ARE CONNECTED TO THE OUTPUT OF THE SUBTRACTOR 47 AND TO THE OUTPUT OF THE LOGARITHMIC CONVERTER 41 OF THE SECOND MEASUREMENT, AND THE TRANSMITTER 35 AND RECEIVER 37 ULTRA-SOUND OF THE SECOND MEASUREMENT TRACK BEING PLACED ON SHAPING PRISMS 36, 38 FIXED TO THE WALL OF THE CONTAINER 49 CONTAINING THE MEDIUM TO STUDY 1. THE DEVICE IN QUESTION CAN BE USED IN PARTICULAR IN THE TRANSFORMATION INDUSTRY MINERALS AND THE CHEMICAL INDUSTRY.

Description

The present invention relates to the means for measuring the parameters of the

  technological processes and particularly relates to a method for measuring the parameters of the solid phase of a suspension and a device for carrying out this method ,. The method for measuring the parameters of the solid phase of a suspension according to the invention and the device for producing it can be used in the mineral processing industry and the chemical industry, in the building and in the branches. to measure the concentration, the size and the mineralogical composition of the particles of crushed material

in a gas supension.

  There is currently a wide variety of methods for measuring the parameters of the solid phase

of a suspension.

  Thus, a method and a device for measuring the particle size of the solid phase of a suspension are widely used (see "Testing and control of technological enrichment processes" by Khan GA, Moscow, Editions "Nedra", 1979, pp. 119-120), based on the determination of the position of a reciprocating micrometer probe in the flow of the suspension to be studied, at the moment of its arrest due to the particles. of solid phase retained between the surface of the micrometer probe and that of the trough

conveying the medium to be studied.

  The existing method and device have the disadvantage of rapid wear and therefore reduced reliability of the micrometer probe which is permanently in contact with the abrasive particles of the suspension to be studied. This results in a dispersion of the results of measurements of phase particles of the same size, that is to say a loss of accuracy of the measurements. There is also a method and a device for measuring the particle size of the solid phase of a suspension (see "Analyzer scanning photosedimentograph 20", presentation sheet of the company "FRITSCH" D-6580, IDAR-Oberstein -1 (FRG) implementing the measurement of the precipitation time of the particles of the solid phase of the suspension in a

vase of water.

  However, said method requires that the suspension to be studied be taken beforehand on the technological flow, that the solid phase be isolated, weighed and brought to the

  measured. This leads to an extended duration of measurements, of the order of 20 to 40 minutes, which significantly deteriorates its application possibilities.

  There is a method for measuring the parameters of the solid phase of a suspension (see the advertisement of Armco Grinding Systems company "Take Control of Your Grinding Circuit") based on the emission, in the medium to ultrasonic waves of two fixed frequencies and on the measurement of the amplitude of the ultrasound transmitted by the medium to be studied, which gives information on the concentration of the solid phase and that of the reference particle size class of the solid phase of the suspension to be studied, the suspension to be studied being degassed before the ultrasound is passed into a special reservoir by the combined effect of vacuum and centrifugal forces produced by

  a stirrer pallet in rotation.

  There is a device for carrying out this method of measuring the parameters of the solid phase of suspensions (see ibi-d) comprising two measurement channels each of which comprises in series a pulse generator, a power amplifier, a transducer-transmitter ultrasound, an ultra-sound transducer-receiver, a received pulse amplifier and an electronic gate. The device also contains a monostable placed between the pulse generator and said gate and, in addition, a switch mounted between the pulse generators of the channels, a multivibrator which has its output connected to the input of the switch, a comparator, a setpoint device, a test mode mode switch, a recorder and a mechanical bubble separator consisting of an air discharge tank and an agitator paddle with a drive motor. The emitter and receiver transducers of the measuring channels are fixed directly on the walls of the container containing the medium to be studied. However, since said measuring method and said device for carrying it out require a prior evacuation of the gas phase from the medium to be studied, and consequently the presence of a mechanical separator of gas bubbles, that is to say of a device with a rotary stirrer pallet, the reliability of the measurements of the parameters of the solid phase

  suspension is significantly reduced.

  The abrasive particles of the suspensions to be studied are at the origin of intense wear of the rotating parts of the mechanical separator of gaseous bubbles, which causes variations in its characteristics and, consequently, an alteration of the degassing quality during operation. . The requirement of maintaining the required level of degassing quality requires periodic stops of the device for measuring the parameters of the solid phase of suspensions, its maintenance and the replacement of worn mechanical elements. The high power consumption of the drive motor of the stirrer pallet, which operates continuously, incurs additional costs. In this way, the presence of the mechanical gas-bubble separator compromises the reliability, deteriorates the measurement accuracy and increases the cost both of

  the entire measuring device than its use.

  The invention therefore relates to a method for measuring the parameters of the solid phase of a suspension and a device for producing it, making it possible to improve the accuracy and the reliability of the measurements of the concentration of the solid phase and that of the reference particle size class of the solid phase of the slurry to be studied, by eliminating the mechanical separator of gaseous bubbles and by measuring the concentration of the useful component in the fractions

  reference of the medium to be studied.

  The object thus achieved is achieved by the fact that in a method of measuring the parameters of the solid phase of a suspension, consisting of generating ultrasonic pulses, passing them through the medium to be studied comprising the suspension and measuring the amplitude of the ultrasound transmitted by this medium, according to the invention is further produced lambian waves and is passed through the wall of the container containing the medium to be studied, after which the amplitude of the lambian waves having a given distance on the wall of the medium container to be studied, this amplitude characterizing the concentration of the solid phase of the suspension, the ratio of the difference in the logarithms of the measured amplitudes of the ultrasound waves having passed through the medium to be studied is then calculated. and lambian waves which have traveled said given distance on the wall of the medium container to be studied at the logarithm of said lambian waves, report representative of the concentration of the reference granulometric class of the solid phase of the suspension, acoustic currents and a radiation pressure whose intensity is proportional to the mass of the particles of the phase are then produced in the medium to be studied. of the suspension, and for a number of fixed intensity values of the acoustic currents and the sound radiation pressure, the quotient of said ratios found in the presence of these fixed values of intensity of the acoustic currents and the sound radiation pressure by the same magnitude without the effect of acoustic currents and sound radiation pressure, which quotient characterizes the concentration of the useful constituent in the fractions

  reference of the suspension to be studied.

  This offers the possibility of measuring the concentration of the solid phase, the concentration of the solid phase belonging to a certain reference size class and the concentration of the useful constituent of the reference fractions of the medium to be studied without having to degas it beforehand, which facilitates measurements and increases their reliability and accuracy. It is also useful to form two levels of measurement of the durations of the ultrasonic impulses transmitted by the medium to be studied and of the Lambian waves which have traveled a fixed distance on the wall of the container containing the medium to be studied by successively limiting their amplitude; the measurement levels of the durations of these pulses are modified in proportion to their amplitude, the duration of the pulses captured at the levels thus formed is measured, the difference of the values measured for the Lambian waves which have traveled the fixed distance on the wall of the container containing the medium to be studied, this difference characterizing the concentration of the solid phase of the suspensions, the ratio of the difference of the measured values of the ultrasound transmitted by the medium to be studied is also calculated, unlike the values measured for the waves. which have traveled the fixed distance on the wall of the receptacle containing the medium to be studied, without the effect of the acoustic currents and the sound radiation pressure, this ratio representing the concentration of the reference granulometric class

  of the solid phase of the suspension.

  This makes it possible to improve the accuracy of the measurement of the concentration of the solid phase, of the reference particle size class of the solid phase and of

  the concentration of the useful component in the reference fractions of the medium to be studied in the cases where the volume concentration of the gaseous phase exceeds that of the solid phase.

  The object described above is also achieved by the fact that the device for measuring the parameters of the solid phase of a suspension comprising two measurement channels, each of which contains, connected together in series, a pulse generator and a transducer. ultra-sound transmitter, as well as, connected together in series, a

  ultra-sound transducer-receiver and an amplifier of the received signal, the transducer-transmitter and the transducer-

  the receiver-receiver of the same measurement channel being fixed directly on the walls of the container containing the medium to be studied, comprises, according to the invention, in each measurement channel, a logarithmic converter connected to the output of the signal amplifier received, a subtractor which has its inputs connected to the outputs of the log converters of the two channels, and a divider at the inputs of which are connected the output of the subtractor and the output of the logarithmic converter of the second measurement channel, the ultrasonic transducers transmitter and receiver of the second way

  measuring devices being placed on forming prisms fixed to the wall of the container containing the medium to be studied.

  The forming prisms can be carried by a plate closing a longitudinal slot in the wall of the container containing the medium to be studied and fixed.

to the wall of the container.

  This makes it possible not to use the mechanical bubble separator of the suspension phase solid phase parameter measuring device, which not only improves the accuracy and reliability of the overall device, but also reduces the cost. of manufacture and use. Yet another advantage of the device is that it is possible to simultaneously measure the concentration of the solid phase and that of the reference grain size class of the solid phase of the medium to be studied. Each measurement channel may comprise a pulse expander which has its input connected to the output of the received pulse amplifier, and its outputs to the inputs of the subtractor the output of the pulse expander of the second. measuring channel being more -related

at the entrance of the divider.

  It is useful that the device comprises a counter having its input connected to the output of the received signal amplifier, an OR logic whose output is connected through its own delay line to the inputs of the pulse generators, a decoder having its inputs connected to the output of the counter, and its output, at the input of the logic circuit OR, and a control circuit of the process for measuring and calculating the parameters of the solid phase of the suspension,

  cooperating with the decoder and with the OR logic circuit.

  This solution makes it possible simultaneously to measure the concentration of the solid phase, that of the reference particle size class of the solid phase and that of the useful constituent of the reference fractions of the suspension to be studied, without having to

  first eliminate the gas phase.

  It is advantageous for the control circuit of the measurement and calculation process of the solid phase parameters of the suspension to contain, connected to one another in series, a second OR logic circuit, a third pulse generator and a third fixed transmitter-transmitter. on the wall of the container above the first two and facing the transducers placed on the forming prisms, the inputs of the second OR logic being connected through its own monostable to the inputs of the first OR logic circuit and outputs

of the decoder.

  It is also useful that the control circuit of the measurement and calculation process of the parameters of the solid phase of the suspension comprises at least four identical circuits comprising, interconnected in

  series, a delay line, a first electronic door

  that, an amplitude detector and a second electronic gate, and that it also comprises a second divider whose inputs are connected to the outputs of all the circuits and whose output constitutes the information output of the entire device, the outputs of at least three circuits having a common point, the inputs of the delay lines of all the circuits being connected to the inputs of the decoder, the information input of the first gate of each circuit being connected to the output of the first divider, the control input of the second gate of the first circuit, through a logic circuit OR and a monostable connected together in series, the control input of the second gate of the other circuits whose outputs are joined together , through their own monostable, and the control input of the amplitude detector of each circuit

  being connected to the outputs of the decoder.

  It is advantageous that, in each measurement channel, the output of the log converter is connected to the following elements connected in series with a delay line, an amplitude limiter, a control circuit and a difference calculator. durations of impulses at various levels of limitation, the

  output of each of these elements being connected to the input 25 of the subtracter.

  The device may have two forming circuits of identical limitation levels, each having a limitation level selector which has its input connected to the output of the respective log converter 30, and its output to the control input of the respective amplitude limiter. , and, connected to the respective amplitude limiter, the following elements connected together in series: a second amplitude limiter and a control circuit of a clock whose output is connected to the input of the computing device differences

respective durations.

  It is possible that in each channel, at the output of the log converter is connected a second limit level selector whose output is connected to the control input of the respective second amplitude limiter. The technical solution which is the subject of the invention makes it possible to improve the measurement accuracy of the parameters of the solid phase of the suspensions in the cases where the concentration of the gas phase exceeds in volume that of the solid phase, without having to eliminate

beforehand the gas phase.

  The invention will be better understood and other purposes, details and advantages thereof will become more apparent in the

  light of the following explanatory description of various embodiments given only to

  Nonlimiting examples with reference to the accompanying non-limiting drawings in which: FIG. 1 schematically illustrates the operations of the method for measuring the parameters of the solid phase of a suspension, according to the invention; FIG. 2 schematically illustrates the operations of the method for measuring the parameters of the solid phase of a suspension, with control of the duration of the ultrasonic pulses transmitted by the medium to be studied and of the Lambian waves which have traveled a fixed distance. on the wall of the container containing the medium to be studied, according to the invention; FIG. 3 represents a block diagram of a device implementing the method for measuring the parameters of the solid phase of a suspension, which measures the concentration of the solid phase and that of the reference particle size class of the solid phase. of the suspension, according to the invention; FIG. 4 is a block diagram of a device implementing the method for measuring the parameters of the solid phase of a suspension, which measures the concentration of the solid phase, the concentration of the reference particle size class of the solid phase and that of the useful component of the reference fractions of the medium to be studied, according to the invention; - Figure 5 is a block diagram of a device implementing the method of measuring the parameters of the solid phase of a suspension, which measures. the concentration of the solid phase and that of the reference particle size class of the solid phase, with control of the duration of the ultrasonic pulses 15 sensed, transmitted by the medium to be studied, and Lambian waves which have traveled a fixed distance on the wall of the container containing the medium to be studied,

according to the invention.

  The method for measuring the parameters of the solid phase of a suspension according to the invention consists of

what follows.

  Ultrasound waves 2, the length of which is commensurable with the particle size of the solid phase of the suspension to be studied, are produced and passed through a medium to be studied 1 (FIG. 1). 2 sounds in the suspension 1, there is absorption and dissipation of their energy, the dissipation of ultrasound 2 prevailing considerably on the absorption when the size of the particles is commensurable with their wavelength. However, overall, the importance of the attenuation of ultrasound 2 of a fixed frequency in the suspension to be studied is determined by the concentration and size of the solid phase particles. The ratio between the absorption and dispersion components of ultrasound 2 then depends on the quantity of solid phase particles whose size is of the same order of magnitude as the length of the waves 2 used. The disturbance of the measurements of the attenuation of ultrasound 2 in the suspension to be studied is due to the gaseous bubbles. Ultrasonic attenuation 2

  on gaseous bubbles has a well-marked resonance character.

  With the growth of the frequency of ultrasound 2, the amount of resonant-sized bubbles in the medium to be studied 1 undergoes a sharp decrease to become practically zero at frequencies greater than 5 MHz. This is because the resonant frequency of the gaseous bubbles decreases with the decrease of their size and, when it reaches a certain

  limit, the gaseous bubble dissolves in water.

  In this way, the attenuation of the high frequency ultrasound propagating in the medium to be studied depends practically only on the size of the solid phase particles and their concentration, and only in high concentrations of the phase

  It is influenced by gaseous bubbles of non-resonant size.

  Simultaneously, lambian waves 3 are produced and passed through the wall of the container containing the medium to be studied 1. However, the attenuation of the Lambian waves 3 in the wall of the vessel is determined only by the distance traveled and by the concentration of the solid phase of the medium to be studied 1 irrespective of the size of the solid phase particles and the concentration of the gaseous bubbles (given their low mass). After the ultrasound 2 has traveled through the medium to be studied 1, and the lambian waves 3, a fixed distance Y on the wall of the container containing the medium

  to study 1, we measure their amplitude 4,5. The logarithms 5, 6 of the measured amplitudes 4.5 and the logarithmic difference 8 are calculated.

Size 9 equals

S = S2 - S1

S1

  S1 o S1 is the logarithm of the amplitude of the lambian waves 3 which have traveled a fixed distance I on the wall of the container containing the medium to be studied 1; S2 is the logarithm of the amplitude of the ultrasound transmitted by the medium to be studied, represents the concentration of the reference granulometric class of the solid phase of the suspension.

  to study 1, that is to say the concentration w of the particles of crushed material whose size is greater or less than the reference.

  The difference of particles of known size from the equilibrium state or the established path of their movement under an external effect in a suspension of known concentration is determined by their specific gravity. In the case where the specific weight of the useful constituent of the medium to be studied 1 is known and that, therefore, it is possible to estimate in advance the deviation of the particles of this constituent of any size, the difference of the rest of the particles of known size relative to the equilibrium state or to the established trajectory of their movement characterizes the concentration of the useful constituent in the reference fractions of the suspension at

to study 1.

  In order to measure this magnitude in the medium to be studied 1, acoustic currents and a pressure of the sound radiation 10 are formed under the effect of strong ultrasonic waves. The intensity of the acoustic currents and the pressure is regulated. of sound radiation by varying the amplitude 11 of the powerful ultrasonic waves. Their action on the different fractions of the medium to be studied is thus obtained. The ratio 12 of the size S is calculated for the medium to be studied, O without the effect of the powerful ultrasonic waves, at the same size S but under effect of the acoustic currents and the pressure of sound radiation 10 of known intensity, this ratio characterizing the concentration r of the

  constituent useful in the reference fractions of the suspension to be studied.

  In the case where the volume concentration of the gaseous phase is commensurable with the solid phase, which is very rare in practice, it is advantageous, for reasons of precision of measurement of the parameters of the solid phase of the suspension, to carry out a double treatment of the medium to be studied 1 by the acoustic currents and the sound radiation pressure 10. In the first stage, before the arrival of the medium to be studied 1 in the measurement zone of the parameters of its solid phase, 25 which favors the degassing to the atmosphere, and the second, to measure the concentration of the useful constituent in the reference fractions of the medium to be studied

  in accordance with the above.

  The measurement accuracy of the concentration of the solid phase and that of the reference particle size class of the solid phase of the suspensions in case of high concentration of the gas phase can be

  also improved in another way.

  For this purpose, the shape change of the ultrasonic pulses 2 transmitted by the medium to be studied 1 and Lambian waves 3 which have traveled a fixed distance 1 on the wall of the container containing the medium to be studied are analyzed. The inertial properties of the suspension to be studied 1 have the effect of altering the initial shape of the pulse. In the case where an emitted pulse is rectangular, this results in a progressive rise and fall, respectively, of its front edge and its rear edge. The inertial properties of the actual suspensions are determined, practically, only by the concentration and fractional composition of their solid phase because the mass of the particles of the milled material exceeds a few orders of magnitude.

that of gaseous bubbles.

  The crushed material particles move with the liquid transporting them in an ultrasonic field. The character of this movement depends on the frequency of the ultrasounds and the size of the particles: with the growth of the size of the solid particles, for a fixed frequency of the ultrasounds, or with the growth of the frequency of these particles. here, but for a size

  As the particles of crushed material are constant, these particles are increasingly exceeded by the moving liquid.

  The difference in the inertia properties of the medium to be studied is manifested by a modification of the shape of the ultrasonic pulses 2 transmitted by the medium to be studied 1 and Lambian waves 3 which have traveled a fixed distance 30 on the wall of the container containing the medium to be studied 1, and is determined by the frequency of the ultrasound by the concentration and by the fractional composition of the phase

solid of the suspension.

-2599503

  After the measurement of the amplitude 4, 5 of the ultrasonic pulses 2 and the Lambian waves 3, two

  levels 13, 14 (Figure 2) at which their durations are measured.

  For this purpose, the received pulses are successively limited in amplitude. The limitation levels, 16 are chosen so that the ratio of the measured amplitude 4, 5 of the pulses received to the value

  absolute amplitude at said levels is constant.

  After having measured at the two levels 13, 14 the durations 17, 18 of the ultrasonic pulses 2 transmitted by the medium to be studied 1 and Lambian waves 3 which have traveled a fixed distance λ on the wall of the container containing the medium to be studied 1, we evaluate the

  differences 19, 20 between the durations of each pulse 15 at both levels 13, 14.

  The difference of the pulse durations of the Lambian waves which have traveled a fixed distance λ on the wall of the container containing the medium to be studied 1

  characterizes the solid phase of the suspension.

  The ratio 21 of the difference 19 between the durations 17, 18 of an ultrasonic pulse 2 transmitted by the medium to be studied 1 to the difference between the pulse durations of the Lambian waves 3 having traveled the fixed distance A on the The wall of the container containing the medium to be studied 1 represents the concentration of the reference particle size class of the solid phase.

of the suspension.

  The device carrying out the method for measuring the parameters of the solid phase of a suspension, which makes it possible to measure the concentration of the solid phase and that of the reference granulometric class of the solid phase of the suspension, comprises two channels of

Measurement I and II (Figure 3). The first measuring channel I comprises, connected together in series, a

  monostable trigger 22, a pulse generator 23, an ultrasonic sound transducer-transmitter 24, an ultrasonic transducer-receiver 25, a received pulse amplifier 26, an electronic gate 27 and a logarithmic converter 28. At the input of the tripping monostable 22 are connected the following interconnected elements in series: a delay monostable 29, a differentiator 30, an amplitude limiter 31, and a monostable trainer 32 whose output is connected to a second input of the

door 27.

  The second measuring channel II comprises, connected to one another in series, a tripping monostable 33, a pulse generator 34, an ultrasonic sound transducer-transmitter 35 placed on a first forming prism 36, an ultrasonic transducer-receiver sound 37 placed on a second forming prism 38, a pulse amplifier

  received 39, an electronic gate 40 and a logarithmic converter 41.

  At the input of the tripping monostable 33 are connected the following interconnected elements in series: a delay monostable 42, a differentiator 43, an amplitude limiter 44 and a monostable former 45 which has its output connected to a second entrance to the

door 40.

  The trigger monostables 22 and 33 have their inputs connected to a multivibrator 46. Between the logarithmic converters 28 and 41 of the two measurement channels I and II there is a subtractor 47 which has its output connected to one of the inputs of the divider 48 having a second input connected to the output of the converter

  logarithmic 41 of the second measurement channel II.

  The ultrasonic transmitters transmitter 24 and receiver 25 of the first measuring channel, as well as the forming prisms 36 and 38 of the second measurement channel II, are placed on the container 49 containing

the environment to be studied 1.

  The multivibrator 46 delivers pulses each of which triggers, by means of the trigger monostables 22 and 33, the pulse generators 23 and 34 producing rectangular pulses filled with electrical oscillations of a given frequency. The

  generating time of the pulse generators 23 and 34 and, therefore, the duration of the rectangular pulses which they deliver are determined by the duration of the pulses emitted by the trigger monostables 22 and 33.

  The emitting transducers 24 and 35, for example of the piezoelectric type, transform, by piezoelectricity in reverse, the electrical oscillations into ultrasonic vibrations of the medium with which they

are in contact.

  The first transducer-emitter 24, placed directly on the wall of the container 49 of medium to be studied 1, generates in the material of the wall longitudinal ultrasonic waves 2 which are emitted towards the

suspension to be studied 1.

  The wavelength of the ultrasound 2 produced by the ultra-sonic transducer-emitter 24 is of the same order of magnitude as the particle size of the solid phase of the medium to be studied 1. In this case, the frequency of the ultra-sound The products must be such (ie sufficiently high) so that there are no gaseous bubbles of resonant size. The attenuation of ultrasound 2 transmitted by the environment to be studied

  1 is then determined only by the size of the solid phase particles and their concentration.

  In order to evaluate the concentration of the solid phase, the attenuation of the lambian waves 3 which have traveled a fixed distance t on the wall of the container 49 containing the medium to be studied is measured. In order to generate the Lambian waves 3, the transducer ultrasonic transmitter 10 35 is placed on a shaping prism 36 fixed to the wall of the

  container 49 containing the medium to be studied 1.

  The angle at which the ultrasonics are injected by the forming prism 36 into the wall of the container 49

  containing the medium to be studied 1 is selected so as to reveal lambian waves 3.

  During the propagation of the lambian waves 3 in the wall of the container 49 containing the medium to be studied 1, their attenuation is determined only by the concentration

  of the solid phase of the suspension.

  The ultrasonic transducer-receiver 25 transforms, by direct piezoelectricity, the ultrasound 2 transmitted by the medium to be studied 1 into electrical oscillations. A similar operation is also performed by the ultrasonic transducer-receiver 37 for Lambian waves 3 which have traveled a fixed distance on

  the wall of the container 49 of medium to be studied 1.

  The received signals are amplified by the received pulse amplifiers 26 and 39 and are then applied

at gates 27 and 40.

  The pulses coming from the multivibrator 46 trigger the delay monostables 29 and 42 which deliver rectangular pulses, for example of positive polarity, whose duration is equal to the minimum propagation time of the ultrasound 2 in the medium to be studied 1 and the minimal time that the lambian waves 3 put to travel a fixed distance on the wall of the container 49 containing the medium to be studied 1, respectively. The differentiators 30 and 43 differentiate the positive rectangular pulses provided by the delay monostables 29 and 42 by forming a succession of two short pulses, one of which is positive and the other negative. The amplitude limiters 31 and 44 pass only the second pulse (negative), and it is this which triggers the monostable trainers 32 and 45. The duration of the pulses delivered by the monostable trainers 32 and 45 is selected from it corresponds to the informative part of the ultrasonic impulses transmitted by the medium to be studied 1 and Lambian waves 3 which have traveled a fixed distance. on the wall of the container 49 containing the medium

to study 1.

  The pulses coming from the monostable forformers 32 and 45 turn on the doors 27 and 40, which thus allow only the information part of the ultrasonic pulses 2 transmitted by the medium to be studied and the Lambian waves 3 which have traveled

  a fixed distance on the wall of the container 49 containing the medium to be studied 1.

  The amplitude of the Lambian waves 3 which have traveled a fixed distance on the wall of the container

  49 containing the medium to be studied 1 characterizes the concentration of the solid phase of the suspension.

  The logarithmic converters 28 and 41 calculate the logarithms of the amplitudes of the signals whose

  passage was authorized by gates 27 and 40.

  Subtractor 47 calculates the logarithmic difference

  The device for carrying out the method for measuring the parameters of the solid phase of a suspension, making it possible to measure the concentration of the solid phase, that of the granulometric class of reference of the solid phase and that of the useful constituent in the reference fractions of the medium to be studied comprises,

  also, two measurement channels (Figure 4).

  The first measurement channel comprises, connected to one another in series, the pulse generator 23, the ultra-sound transducer-transmitter 24 placed on a waveguide, the ultrasonic-sounding transducer-receiver 25 placed on

  a waveguide 51, the received pulse amplifier 26 and a pulse expander 52.

  The second measurement channel comprises the series mounting of the pulse generator 34, the ultrasonic sound transducer-transmitter 35 placed on the forming prism 36, the transducer-receiver 37 placed on the forming prism 38, 20 of the amplifier of the amplifier. received pulse 39 and a pulse expander 53. The received pulse amplifiers 26, 39 of the first and second measurement channels

  are realized in the form of logarithmic amplifiers.

  The pulse expander 52 and 53 of the two measurement channels have their outputs connected to the inputs of the subtractor 47 whose output is connected to one of the inputs of a divider 48 having its second input connected to the output of the expander of pulses 53 of the second channel

measurement.

  The output of the first divider 48 is connected to the second inputs of the first (27), the second (40), a third (54) and a fourth (55) electronic gate, each having their first input together. , 259 through a first (56), a second (57), a third (58) and a fourth (59) delay line, to the first four outputs of a decoder 60 which are also connected to the inputs of a OR logic circuit 61 whose output is connected, through a fifth (62) and a sixth (63) delay line, to the inputs of the pulse generators 23 and 34 of the two measurement channels. A second, a third and a fourth output of the decoder 60 are connected to a first (64), a second (65) and a third (66) monostable which have their outputs connected to the inputs of a first logic circuit. OR 67 whose output is connected through

  a third generator 68 to a third ultrasonic transmitter transducer 69.

  The outputs of the first (27), second (40), third (54) and fourth (55) gates are connected to first inputs of a first (70), a second (71), a third ( 72) and a fourth (73) amplitude detector, which have their second inputs connected to an eighth output of the decoder 60, their outputs being connected to first inputs of a fifth (74), a sixth (75), a seventh (76) and a

eighth (77) electronic door.

  The output of the fifth gate 74 is connected to a first input of a second divider 78, a second input of which is connected to the outputs of the sixth (75), seventh (76) and eighth (77) gates, having their second inputs connected through a fifth (79), sixth (80) and seventh (81) monostable to fifth, sixth and seventh outputs of the decoder 60 and to the inputs of a second OR logic 82 whose output is connected through

259950L

  a fourth monostable 83 to a second entry of the

fifth door 74.

  At the input of the decoder 60 is connected a counter

84 connected to multivibrator 46.

  The third ultrasonic transducer-transmitter 69 is placed at the top of the container 49 containing the medium to be studied 1, at the bottom part are fixed the waveguides 50 and 51 carrying the ultrasonic transducer-transmitter 24 and the ultra-transducer-receiver. 25 of the first measurement channel, and the forming prisms 36 and 38 with the transmitter 35 and receiver transducers

  37 ultrasonic sound of the second measurement channel.

  The forming prisms 36 and 38 can also be installed on a measuring plate closing a longitudinal slot in the wall of the container 49 containing the

environment to be studied 1.

  The device for measuring the parameters of the phase

  solid of a suspension, shown in Figure 4, operates in the following manner.

  The multivibrator 46 delivers rectangular pulses to an electronic impulse dispenser using a counter 84 and an eight output decoder 60. In this way, one control cycle consists of eight sequences. In the first sequence, the pulse from the first output of the decoder 60, through the OR logic 61, the fifth (62) and the sixth (63) delay lines, triggers the first (23) and the second (23) (34) pulse generators. In order to reduce the interference between the measurement channels, the delay of the pulses through the delay lines 32 and 63 is adopted so as to shift in time the generation periods of the first (23) and second (34) generators pulses used to produce frequency HF wave trains and

of fixed duration.

  The ultra-sonic transducer-transmitters 24 and, for example of the piezoelectric type, transform the electrical signal into elastic vibrations of the medium with which they are in contact. The first ultrasonic transducer-emitter 24 transmits ultrasound to the study medium 1 through the first waveguide 50 in the container 49, to the first ultrasonic transducer-transducer 25 placed on the second waveguide 51. The second ultrasonic transducer-transmitter 35 via the first forming prism 36, forms

  in the wall of the container 49 (or in the measuring plate), lambian waves 3 which, after passing through the second forming prism 38, are received by the second ultra-sound transducer-receiver 37.

  The attenuation of high frequency ultrasound 2 during their passage, through the medium to be studied 1, from the first ultrasonic transducer-emitter 24 to the first ultra-sound transducer-receiver 25, is practically only determined by the size Particles of the phase

solid and their concentration.

  The attenuation of the Lambian waves 3 over a fixed distance> S on the wall of the container 49 containing the

  The medium to be studied is determined by the concentration of the solid phase of the suspensions alone.

  The ultrasonic (elastic) waves 2 transmitted by the medium to be studied 1 and the Lambian waves 3 which have traveled through the wall of the container 49 containing the medium 30 to be studied 1 are transofrmées in electrical oscillations

  by the ultrasonic transducer-receivers 25 and 37.

  High frequency electrical oscillations

  are amplified and detected in the amplifiers

  As the duration of the pulses thus formed is short, the pulse expander 52 and 53

  increase it without modifying the amplitude.

  The subtractor 47 provides the logarithmic difference of the received signals and the first divider 48 calculates the magnitude S. The amplitude of the lambian waves 3 which have traveled a fixed distance on the wall of the container 49 containing the medium to be studied I characterizes the concentration of the solid phase of the medium to be studied 1 and the size S represents the concentration of the reference particle size class of the solid phase particles of the suspension to be studied. The pulse coming from the first output of the decoder 60, passing through the first delay line 56 makes conductive the first gate 27. Its delay through the first delay line 56, determined by the propagation time of the ultrasound 2 in the medium to be studied 1 and Lambian waves 3 in the container wall 49 containing the medium to be studied 1, is chosen so as to pass the first gate 27 to the moment of

  determining the magnitude S in the divider 48.

  The first amplitude detector 70 fixes ("memorizes")

the size So.

  The second, third, and fourth control sequences operate in the same manner as the first, since the second, third, and fourth pulses from the second, third, and fourth outputs, respectively, of the decoder 60 also trigger. via the OR logic circuit 61, the

  pulse generators 23 and 34.

  Simultaneously, each of these pulses triggers the first (64), second (65) and third (66) monostable which, via the logic circuit OR 67,

259-9503

  attack the third generator 68 producing powerful electrical oscillations, transformed by the

  third ultrasonic transducer-transmitter 69 in elastic vibrations of the medium.

  The powerful ultrasonic waves 2 produce acoustic currents and sound radiation pressure causing the solid phase particles to move in the medium to be studied 1 from the third ultrasonic transducer-transmitter 69 towards the wall of the container 49. who carries the forming prisms 36 and

38 of the second measurement channel.

  The displacement of the solid phase particles leads to a change in their size distribution and concentration near the wall of the container 49 which carries the forming prisms 36 and 38 of the second measuring channel and between the waveguides 50 and 50. 51 of the first lane

measurement.

  For particles having the same size and arranged at a fixed distance from the third ultra-sound transmitter transducer 69, the importance of the redistribution of these parameters depends only on the specific weight of the

matter that constitutes them.

  In practice, this material generally represents a set of several constituents, one of which is useful, and it is the concentration of the latter that

it's about measuring.

  Since the specific gravity of the useful constituent is known, the displacement of the particles of known size, constituted solely by this constituent, under the effect of the acoustic currents and the sound radiation pressure, is determined analytically or experimentally.

of known intensity.

  The intensity of their action varies with the amplitude or the duration of application of the powerful ultrasonic vibrations provided by the third transducer-transmitter

ultra-sound 69.

  In the case where the action of the powerful ultra-sound vibrations of fixed amplitude takes on a pulse character, the importance of the effect of the acoustic currents and the sound radiation pressure they cause to act on a particle of the solid phase of the suspension depends

the pulse duration.

  The duration of the pulses produced by the first (64), second (65) and third (66) monostable is chosen so that the action of the acoustic currents and the sound radiation pressure is sufficient to cause the particles to be displaced by three ( and in the general case, a larger number) particle size classes

  reference of the solid phase of the suspension.

  II The value of S calculated in each case (S, SII, SIII) is applied, through the second (40), third (54) and fourth (55) gates, made by pulses from the second, third and fourth pulses. outputs of the decoder 60 and delayed by the delay lines 57, 58 and 59, the second, third and fourth amplitude detectors 71, 72, 73, which determine their amplitude. The delay time of the pulses by the delay lines 57, 58 and 59 is determined by the same conditions

  only in the case of the delay line 56.

  The pulses coming from the fifth, sixth and seventh outputs of the decoder 60, through the fifth, sixth and seventh monostables 79, 80 and 81 pass successively the sixth (75), seventh (76) and

eighth (77) doors.

  In this case, each of the pulses of the fifth, sixth and seventh outputs of the decoder 60 conducts

  via the second OR logic 82 and the fourth monostable 83, the fifth gate 74.

  The values of S and SI, S and SII, S and III oo SIII are applied in pairs to the second divisor, which calculates the concentration r of the useful constituent: r = S (i) i = I, II According to another particular embodiment of the device for measuring the parameters of the solid phase of a suspension, shown in FIG. 5, the device again comprises two measurement channels. The first channel comprises, connected together in series, the pulse generator 23, the power amplifier 85 and the ultrasonic transducer-transmitter 24, as well as a series connection of the ultra-sound transducer-receiver. 25, the received signal amplifier 26, the electronic gate 27, the logarithmic converter 28, the delay line 56, a first amplitude limiter 31, a first control circuit 86 of the clock 87 and a calculator of the difference in pulse durations

88 at various levels of limitation.

  Between the generator 23 and the gate 27 there is a

  blocked oscillator 89, and between the logarithmic converter 28 and the limiter 31, a limiting level selector 90.

  At the output of the limiter 31 is connected a series connection of the second amplitude limiter 44, a second clock control circuit 91 and a clock 92 which has

  its output connected to the second input of computing unit 88.

  Between the logarithmic converter 28 and the

  second amplitude limiter 44, there is a second limitation level selector 93.

  The second measurement channel comprises, connected between

  the pulse generator 34, a power amplifier 94, the ultrasonic sound transducer-transmitter 35, the ultra-sound transducer-receiver 37, the ampli fi er

  received pulse driver 39, the gate 40, the logarithmic converter 41, the delay line 57, a third amplitude limiter 95, a third clock control circuit 96, a third clock 97 and a sub-tractor 98 calculating the difference of the pulse durations at various limitation levels 98. Between the pulse generator 34 and the gate 40 there is a locked oscillator 99. Between the logarithmic converter 41 and the third amplitude limiter 95 is a third 10 limitation level selector 100. Between the third amplitude limiter 95 and the subtraction member 98 is inserted a series connection of a fourth amplitude limiter 101, a fourth control circuit 102

  clock and a fourth clock 103.

  Between the logarithmic converter 41 and the fourth amplitude limiter 101 there is a fourth limit level selector 104. Between the units 88 and 98 for calculating the difference of the pulse durations at various levels of limitation is interposed the subtrac 20 47 which has its output connected to an input of the divider 48, a second input is connected to the output of the body 98 for calculating the difference in pulse times at various levels of limitation. Between the pulse generators 23 and 34 there is a switch 105 whose input is connected to the multivibrator 46. The ultrasonic transducer-transmitter 35 is carried by the forming prism 36, and the ultrasonic transducer 37, by the forming prism 38. A measuring plate 106 closes

  a longitudinal slot 107 of the wall of the measuring container 49.

  The device operates as follows.

  The pulse generators 23 and 34 deliver

  rectangular pulses with sinusoidal filling.

  The frequency of the pulse generator 23 of the first measurement channel I is chosen so that the wavelength of the oscillations it produces is commensurable with the size of the solid phase particles of the medium to be studied. In power amplifiers 85 and 94, the sinusoidal electric oscillations are transformed into ultra-sound elastic vibrations in the middle, emitted by the ultrasonic transducer-transmitter 24 to the medium to be studied 1, the ultrasonic transducer-emitter 35 serving the injecting via the forming prism 36 into the walls of the container 49 or into the measuring plate 106 closing the longitudinal slot 107 of the measurement container 49 containing the medium

  to study 1, in which the Lambian waves 3 are formed.

  The blocked oscillators 89 and 99 are triggered on the front edge of the rectangular pulses formed by the pulse generators 23 and 34 and the pulses they deliver turn on the gates 27 and 40, which, for a period of time chosen, let the signal from the pulse amplifiers pass

received 26 and 39.

  The logarithmic converters 28 and 41 deliver pulses whose amplitude is proportional to the logarithm of the amplitude of the signals that have passed through the

doors 27 and 40.

  The received pulses are applied through the delay lines 56 and 57 to the controlled amplitude limiters 31 and 95. The delay experienced by the pulses is determined by the characteristics of the limiting level selectors 90 and 100 which form a level of delay. limitation corresponding to the value, at this moment, of the amplitude of the received pulse and to the values of the reports of the amplitude of the pulses received at the limiting level. In this way, the absolute value of the level of limitation varies in proportion to the amplitude of the pulse received, the ratio of this level to the pulse amplitude remaining constant. This makes it possible to neutralize the effect of the dispersion of the attenuation values of the ultrasound 2 transmitted by the medium 1 due to the various factors and that of the Lambian waves 3 which have traveled a fixed distance A on the wall of the container 49. the medium to study 1 on the duration of the impulse received

at the measurement levels formed.

  The piloted amplitude limiters 44 and 101, associated with the limitation level selectors 93 and 104, provide the second level of limitation of the received pulse. The clock control circuits 91, 96 and 102 trigger the clocks 87, 92, 97 and 103 at the beginning of the limitation of the amplitude of the pulses received and cut them off as soon as possible.

  that their amplitude starts to decrease.

  The first calculator of the differences of the pulse durations at various limitation levels 88 calculates the difference ck of the durations of the ultrasonic pulse 2 transmitted by the medium to be studied 1 to the adopted measurement levels and the calculator of the differences. Pulse durations at various limiting levels 98 calculate the difference in Lambellian pulse duration 3 which has traveled the wall of the container 49 containing the medium to be studied 1. Subtractor 47 provides the difference

du_ / 3.

  The divider 48 calculates the magnitude S0 characterizing the concentration of the reference particle size class of the solid phase of the suspension: S = The size S0 is transformed into a shape signal

* and normal amplitude by a normalizer 104.

  In this way, the methods for measuring the parameters of the solid phase of suspensions and the devices for producing them according to the invention make it possible to measure, without contact, the concentration of the solid phase, the concentration of the reference particle size class of the solid phase. and the concentration of the useful component in the reference fractions of the slurry to be studied without any prior degassing thereof by mechanical means. In this way, the accuracy and reliability of the measurements can be improved and the cost of measuring devices can be reduced.

  solid phase suspensions and their use.

Claims (12)

R E V E N D I C A T I 0 N S   1. Method for measuring the parameters of the solid phase of a suspension, consisting in producing ultrasonic pulses (2), passing them through the medium to be studied (1) comprising a suspension, measuring the amplitude ultrasonic pulses (2) transmitted by this medium, from which the concentration of the solid phase and the concentration of the reference particle size class of the solid phase of the medium to be studied (1), characterized by in addition, lambian waves (3) are produced and passed over the wall of the container containing the medium to be studied (1), after which the amplitude (5) of the lambian waves (3) is measured. - which have traveled a fixed distance - on the wall of the container containing the medium to be studied (1), this amplitude characterizing the concentration of the solid phase of the suspension, then the ratio (9) of the difference (8) of the logarithms (6 and 7) of measured amplitudes of ultra-s (2) having passed through the medium to be studied (1) and lambian waves (3) having traveled said fixed distance on the wall of the container containing the medium to be studied, this ratio (9) corresponding to the concentration of the particle size class reference the solid phase of the suspension.   2. Method according to claim 1, characterized in that further creates, in the medium to be studied (1), acoustic currents and a sound radiating pressure (10) whose intensity is proportional to the mass of the particles of the solid phase of the suspension, then, for several fixed intensity values of the acoustic currents and the sound radiation pressure (10), the quotient (12) of the ratios calculated for several fixed values (11) of intensity of the acoustic currents and sound radiation pressure (10) by the same value without their effect, this quotient characterizing the concentration of the useful constituent in the reference fractions of the suspension to be studied (1). 3. Method according to claim 1, characterized in that two levels (13 and 14) for measuring the duration of the ultrasonic pulses (2) having passed through the medium to be studied (1) are formed. lambian waves (3) having traveled said fixed distance on the wall of the containercontenant the medium to be studied (1), by successively limiting their amplitude, the measurement levels of the duration of said pulses are varied in proportion to their amplitude, we measure the duration (17 and 18) of the pulses received at the levels thus formed, the difference (19) of the values measured for the Lambian waves (3) which have traveled said fixed distance on the wall of the container containing the medium to be studied (1) is calculated (1) , this difference characterizing the concentration of the solid phase of the suspension, as well as the ratio (21) between the difference (20) of the measured values for ultrasound (2) having passed through the medium to be studied (1) and the difference (19) in value s measured for the Lambian waves (3) having run said fixed distance on the wall of the container containing the medium to be studied (1), this ratio representing the concentration of the reference particle size class of the solid phase of the suspension.   4. Apparatus for carrying out the method according to claim (1), comprising two measuring channels (I and II) each of which comprises a series connection of a pulse generator (23, 34), an ultrasonic transducer transducer (24,35), an ultrasonic transducer-receiver 34 (25,37) and a received signal amplifier (26,39), the transmitter (24) and receiver (25) transducers one of the measurement channels being fixed directly on the walls of the container containing the medium to be studied (18, characterized in that it comprises, in each measuring channel I and II, a logarithmic converter (28, 41) connected to the output of the received signal amplifier (26, 39), a subtractor (47) which has its inputs connected to the outputs of the log converters of the two channels, and a divider (48) whose inputs are connected to the output of the subtracter (47) and at the output of the logarithmic converter (41) of the second measurement channel, the ultra-sound transmitter (35) and receiver (37) transducers of the second measurement channel   being placed on forming prisms (36,38) attached to the wall of the container (49) containing the medium to be studied (1).   5. Device according to claim 4, characterized   in that the forming prisms (36, 38) are placed on a plate closing a longitudinal slot of the wall of the container (49) containing the medium to be studied (1) and fixed on the wall of the container (49).   6. Device according to one of claims 4 and 5,   characterized in that each measurement channel comprises a pulse expander (52, 53), each pulse expander having its input connected to the output of the received pulse amplifier (26, 39), and its output , to the subtractor   (47), the output of the pulse expander (53) of the second measurement channel being joined to the input of the divider (48).   7. Device according to one of claims 4, 5 and   6, characterized in that it comprises a counter (84) whose input is connected to the output of the received signal amplifier (26, 39) of each channel, an OR logic circuit (61) whose output is connected through a delay line (62, 63) in each channel to the inputs of the pulse generators (23, 34), a decoder (60) having its inputs connected to the output of the counter (84), and its output, at the input of the OR logic circuit (61), and a control circuit of the process for measuring and calculating the parameters of the solid phase of the suspension, co-operating with the   decoder (60) and the OR logic circuit (61).   8. Device according to claim 7, characterized in that the circuit. for controlling the process for measuring and calculating the parameters of the solid phase of the suspension comprises a series connection of a second OR logic circuit (67), a third pulse generator (68) and a third transducer-transmitter (69) * fixed on the wall of the container (49) above the first two (24 and 35) and facing the transducers (35, 37) 15 placed on the forming prisms (36, 38), the inputs of the second OR logic circuit (67) being connected, through a monostable party to each input (64, 65, 66), to the inputs of the first OR logic circuit (61) and to the outputs of the decoder (60).   9. Device according to one of claims 6 and 7,   characterized in that the control circuit of the process for measuring and calculating the parameters of the solid phase of the suspension comprises at least four identical circuits consisting of the following elements connected together in series: a delay line (56), a first electronic gate (27), an amplitude detector (70), a second electronic gate (74, 75, 76, 77), and a second divider (78) at whose inputs the outputs of all the circuits are connected, and the output of which forms the output of the formation of the entire device, the outputs of at least three of said circuits having a common point, the inputs of the delay lines (56) of all said circuits being connected to the inputs of the decoder (60), the information input of the first gate of each circuit being connected to the output of the first divider (48), the control input of the second gate (74) of the first circuit, via an OR logic circuit (82) and a monostable (83) interconnected in series, the control input of the second gate (75, 76, 77) of the other circuits, the outputs of which are connected together by means of a monostable specific to each circuit (79, 80, 81), and the control input of the amplitude detector (70, 71, 72, 73) of each circuit, being connected at the outputs of the decoder (60).   10. Device according to claim 4, characterized in that, in each measuring channel, the output of the logarithmic converter (28, 41) is connected to a series connection of a delay line (56, 57), an amplitude limiter (31, 95), a control circuit (86, 96) and a pulse width difference calculator at various limiting levels (88, 98), each   of these elements having its output connected to the input of the subtractor (47).   11. Device according to claim 9, characterized in that it has two identical limit level formers each having a limit level selector (90, 100) which has its input connected to the output of the log converter (28). , 41) corresponding, and its output, to the control input of the corresponding amplitude limiter (31, 95), and, connected to the corresponding amplitude limiter (31, 95), a series connection of a second amplitude limiter (44, 101), a control circuit (91, 102) of a clock (92, 103) which has its output connected to the input of the member (88, 98)   corresponding calculation of the differences of durations.   Device according to claim 10, characterized in that, in each measuring channel, the output of the log converter (28, 41) is connected to a second limit level selector (93, 104) whose output is connected. at the control input of the second   corresponding amplitude limiter (44, 101).