Note: Descriptions are shown in the official language in which they were submitted.
~L~8~530
~ETHOD A~D APPARATUS FOR .~ASURIN~ PAR~ T~RS OF
S~LID PHASE O~ SLURXIES
The invention relates to the equipment for measu-
ring parameters of pxoduction processes, and more par-
ticularly, it deals with methods ~or measuring parame-
ters of solid phase of slurries and with an apparatus
for carr~ing out the method.
~ he method and apparatus for measuring parameters
of solid p~ase of slurries according to the invention
may be advanta~eously used in the mining and ore pro-
cessing industry, chemical, construction and nei~hbou-
ring industries for measuring concentration, size and
mineral composition of particles of a comminuted ma-
terial in ~as-containi~ slurries.
~ nown in the art are various methods for measuring
parameters of solid phase of slurries.
Thus a method and apparatus are widel~ used for
measurin~ particle si~e of the solid phase in slurries
~hich are based on determining the position of a micro-
metric feeler~ which reciprocates in the flow of -the
slurry under study, at the moment it is stopped owing
to a solid phase particle being retained bet~een the
surfaces of the micrometric feeler and a trough along
~hich the slurry is supplied.
The prior art method and apparatus are deficient
in a rapid wear, hence, low reliabilit~ of the micro-
metric feeler which is permanentl~ in contact with
~ 3~
anrasive particles of the slurr~ under stud~. This
results in a scatter of results in measurin~ solid phase
particles in slurries having the same particle size,
i.e. in a low accurac~ of measurements.
~ lso known in the art are a method and apparatus
for measuring particle size o~ solid phase o~ slurries
based on the measurement of the -time of settling
of solid phase particles of a slurr~ in a vessel contai-
ning water.
However, the abovementioned method requires pre-
liminar~ sampling of the slurry under study lrom the
production flowS extraction of solid phase from the
slurry sample, weigh~3g and delivery to the place of
measurement. This results in a long measurement time
~about 2~ to 40 minutes) thus greatly restricting the
field of application.
~ nown in the art is a method for measuring parame-
ters of solid phase of slurries based on forming a ra-
diation and directin~ into the fluid under stud~ ultra-
sonic oscillations at t~o fixed frequencies, measuring
the amplitude of ultrasonic oscillations that passed
through the fluid under stud~ a~d assessin~ concentra-
tion of solid phase and concentration of a critical
particle size fraction of solid phase in the slurry
under s-tudy by the value of this amplitude, the slurry
under study bein~ deOassed before direc-ting ultrasonic
oscillations thereinto in a special tank by combined
action of vacuum and centrifugal forces generated b~
an impeller~
~ nown in the art is an apparatus for carr~ing out
the method for measuring parameters of aolid phase
of slurries,comprising two measurement channels, each
consistin~ of a series circuit including a pulse Oene-
rator, a power amplifier, an emitting ultrasonic trans-
ducer, a receiving ultrasonic transducer, a received
pul~se amplifier, and an electronic switch. The appara-tus
also comprises a one-shot multivibrator connected bet-
ween the pulse generator and electronic switch and also
a switching circuit connected bet~een the pulse genera-
tors of the t~o channels, a multivibrator having an
output connected to the input of the switching circuit,
a comparator, a setting means, a stud~ function selec-
tor, a recorder, and also mechanical ~as bubble separator
consistinf o~ a tank for air removal and an impeller
having a drive motor. The emitting and receiving
transducers of one of the measurement channels are
secured directl~ to the walls of a vessel containing
a fluid under stud~.
It should be, however, noted that, as it is neces-
sary in the abovedescribed method and apparatus, to
effect the preliminary removal of gaseous phase from
the fluid under stud~, hence, to have a mechanical gas
bubble separator in the form of an appara~us including
a rotar~ impeller, reliability of the process of measu-
~ ~ 4~3~
rement of parameters of solid phase in slurries israther low.
Under the action of abrasive particles in the
slurr~ under study, intensive wear of rotating parts
of the mechanical gas bubble separator occurs which
results in variations of its characteristi~s, hence,
in Ghan~es in quality of degassing during operation.
~o maintain quality of degassing at the desired level,
re~ular stopp~ge of the apparatus for measuring para-
meters of solid phase o~ slurries is necessary for
maintenance and replacement of worn mechanical componentsO
The drive motor of the impeller consumes much ener~
~hich results in added cost bearing in mind continuous
operation of the measurinæ apparatus. ~herefore, the
use of the mechanical 3as bubble separator lowers re-
liabilit~, impairs accurac~ of measurements and results
in an increased cost o~ both the apparatus for measure-
ment as a whole and its operation.
It is an object of the invention to provide a
method and apparatus for measuring parameters of solid
phase of slurries which make it possible to improve
accurac~ and reliability o~ measurements of concentra-
tion of solid phase and concentration o~ a critical
particle size fraction of solid phase in the slurry
under study.
This is accomplished by that in a method for measu-
ri~g parameters of solid phase of slurries, comprisingforming pulses of ultra 50nic oscillations, causing them
to pass throu6h a fluid un~er stud~ containing a slurr~,
measuring the amplitu~e of ultrasonic oscillations
that passed through the fluid, according to the in~en-
tion, the method also comprises formi~g Lamb waves and
causi~g them to pass along the wall of a vessel con-
taining the fluid under study, measuring the amplitude
of the Lamb waves that passed through a predtermined
distance along the wall of the vessel containi~ the
fluid under study, the amplitude characterizing con-
cen~ration of solid phase of the slurry, computing the
ratio of the differences between logarithms of the
measured amplitudes o~ the ultrasonic oscillations
that passed through the fluid under study and of the
Lamb waves that passed through the prede-termined dis-
tance along the wall of the vessel containin~ the fluid
under stud~ to a logarithm of the measured amplitude
of Lamb waves, the ratio corresponding to concentration
of a critical particle size ~raction of solid phase
o~ the slurry~ formin~ in the fluid under stud~ acous-
tic currents and a radiation pressure o~ a sonic ra-
diation, -the intensit~ of ~hich is proportional to
the mass of particles of solid phase of the slurr~,
determinin~ the quotient of division of the computed
ratios for several fixed values of intensities of
acoustic currents and radiation pressure of a sonic
radiation to the same value obtained without these
factors, which characterizes concentration of a useful
component in critical particle size fractions of the
slurry under study.
The above features allow concentration of solid
phase and concentraticn of a useful component in criti-
cal size fractions of the fluid under stud~ to be
measured without preliminarily removing gaseous phase
from the fluid thus simplifying the measurement process,
improving reliability and accuracy of measurement re-
sults.
It is preferred -that two la~els o~ measurement
of the pulse length of ultrasonic oscillations that
passed through the fluid under study and Lamb waves
-that passed through a predetermined distance along the
wall of a vessel containing the fluid under stud~
be formed by successively limiting their amplitude,
-the levels of measurement of the length of these pulses
bein~ varied proportionall~ with their amplitude, the
length of the received pulses at the levels thus formed
is measured, the difference bet~een the measured values
for the Lamb waves that passed through the predetermined
distance along the ~all of the vessel containing the
fluid under study is computed to characterize concent-
ration of solid phase of the slurry, and also the ratio
of the difference between the measured values for
ultrasonic oscil'a~ions that passed through the ~luid
~34~3
--7--
under study to the difference of the measured values
for the ~amb waves that passed through the predetermi-
ned distance along the wall o~ the vessel containin~
the fluid under study without the action of acoustic
currents and radiation pressure is also computed to
represent concentration of critical particle size frac-
tion o~ solid phase of the slurr~.
This facility makes it possible to improve accu-
racy of measurement of concentration of solid phase,
concentration of the critical particle size fraction
of solid phase and concentration of a useful component
in the critical fractions of the fluid under stud~ in
applications where concentration o~ gaseous phase
has a volume which is larger than that of solid phase.
The object is also accomplished by that an appa-
ratus for measuring parameters of solid phase of a
sl~rr~, comprising two measurement channels, each
haviDg a series circuit including a pulse generator
and an emitting ultrasonic transducer and a series
circuit including a receiving ultrasonic transducer
and a received signal amplifier, the emitting and
receivi~ ultrasonic transducers of one measurement
channel being secured directly to the walls of a vessel
containing a fluid u~er study, according to the
invention, the apparatus also comprises, in each
measurement channel, a logarithmic converter connected
to the output o~ the received signal amplifier, a
o
subtraction unit having inputs to which are connected
the outputs of the logarithmic converters of both
channels~ and a division unit having inputs to which
are connected the output of the subtraction unit and
the output of the lo~arithmic converter of the second
measurement channel, the ultrasonic emitting and recei-
ving transducers of the second measurement channel
bein~ mounted on forming prisms secured to the wall of
the vessel containin~ the fluid under study.
The forming prisms may be mounted on a plate co-
vering lon~i-tudinally extendin~ apertures in the wall
of the vessel containin~ the fluid under study, the
plate being secured to the vessel wall.
~ his construction allows a mechanical Das bubble
separator to be dispensed with in operation of the
apparatus ~or measuring parameters of solid phase of
a slurr~ thus improving accuracy and reliability of the
apparatu~ a whole and also lo~eri~g the cost of its
manufacture and operation. ~he apparatus allows co~-
centration of solid phase to be measured concurrently
~ith concentration of a critical particle size frac-
tion of solid phase of the fluid bçin~ studied.
Each measurement chan~el may comprise a pulse
expander, the input of each expander bein~ connected
to the output of the received pulse amplifier and.the
outputs, to the inputs of the subtractio~ unit, the
output of the pulse expander of the second measurement
_9_
channel bein~ also connected to the input of the divi-
sion unit.
The apparatus preferabl~ comprises a counter having
its input connec-ted to the output of the received si~nal
amplifier, an OR gate having its output connected, via
its own dela~ line, to the inputs of the pulse genera-
tors, a decoder having its inputs connected to the
output of the counter a~d an output connected to the
input of the OR gate, and a control system for control- -
ling the process of measurement and computation of para-
meters of solid phase of slurries cooperatin~ with
the decoder and OR gate.
~ his arrangement makes it possible to conduct measu-
rements of concentration of solid phase, concentration
of a critical particle size fraction of solid phase
and concentration of a useful component in critical
~ractions of the slurry under stud~ without preliminaril~
removing gaseous phase~.
It is preferred that the control s~stem for control-
ling the process of measurement and computation of
parameters of solid phase of a slurr~ under study
comprise a series circuit including a second OR gate,
a third pulse Oenerator and a third emitting transducer
secured to the wall of the vessel above the two former
transducers mounted on formin~ prisms and opposite
thereto, the inputs of the second OR gate bei~ con-
nected 9 Yia its own one-shot multivibrator, to the
-10
lnputs o~ the first OR ~ate and to the outputs of the
decoder.
~ he control system for controlling the measurement
process and for compu-ti~ parameters of solid phase
of a slurry under stud~ preferabl~ comprises at least
four identical series circuits each including: a delay
line, an electronic switch, an amplitude detector
and a second electronic switch, as a second division
unit havin~ inputs to which are connected the outputs
of all these series circuits, the output of this divisio~
unit being the data output of the whole apparatus;
the outputs of at lea-st three of said series circuits
bein~ put together to form a com~on output, the inputs
of said dela~ lines of all said series circuits being
connected to the inputs of said decoder; the data input
of said ~irst electronic switch of each said series`~
circuit bein~ co~nected to the output of said first
division unit; the control input of said second electro-
nic s~itch of said first series circuit bein~ connected,
via a series circuit including an OR gate and one-shot
multivibrator, to the fifth, sixth and seventh out-
puts o~ said decoder, the con-trol input of said second
electronic switch of said other series circuits having
their outputs put together being connected to the
output of said decoder via a respective one-shot
mul-tivibrator, and the control input of said amplitude
detector in each of said series circuits being connected
to the outputs of said decoder. In each measurernent
channel~ the output of the logarithmic converter is
preferabl~ connected to a series circuit including
a delay line, an amplitude limiter, a control cir-
cuit and a unit for compu-tin~ the difference between
pulse lengths at dif~erent limitation levels, the
output of each bei~ connected to the input of the
subtraction unit.
The apparatus ma~ comprise two identical circuits
for formin~ limitation level each comprising a unit
for selectinæ limi-tation level having its input con-
nected to the output of a respective logarithmic conver
ter and the output connected to the control input of a
respective amplitude limiter, and a series circuit in-
cludin~ a second ampliGude limi-ter and a clock control
circuit connected to a respective amplitude limiter,
the clock havi~ its output connected -to the input of
a respective unit for computin~ pulse len~th dlfference.
In each measuremen-t channel, the output of the
logarithmic converter ma~ be connected -to a second unit
for selectin~ limitation level havin~ its output con-
nected to the control input of a respective second
amplitude limiter.
The abovedescribed facilities make it possible
to improve accuracy of measurement o~ parameters of
solid phase in slurries in applioations where concentra-
tion of the gaseous phase is of a volume greater thau
-12-
that of the solid phase, without preliminar~ removal
of the gaseous phase.
~ he invention will now be described in details
with reference to specific e~bodiments shown in the
accompanyin~ drawin~s, in wh~ch.
Fi~ure 1 schematically shows steps of 2 method
for measuring parameters of solid phase of slurries
according to the invention;
Figure 2 schematically shows steps of a method
for measurin~ parameters of solid phase of slurries
with the control of the length of received pulses of
~ultrasonic oscillations that passed throu~h the fluid
under stud~ and Lamb waves that passed through a pre-
determined distance along the wall o~ a vessel con-
taining the fluid under stud~, accordin~ to the in-
vention;
Figure 3 sho~s a block-dia~ram of an apparatus
for carr~ing out the method for measurin~ parameters
of solid phase of slurries which is desi~ned for measu-
ring concentration of solid phase and concentration of
a critical particle size fraction of solid phase of
slurries according to the invention;
Fi~ure 4 shows a block-diagram of an appara~us
for carryi~ out the method for measuring parameters
of solid phase of slurries which is designed for measu-
ring concentration of solid phase, concentration of
a critical particle size fraction of solid phase and
concentration of a useful component in the critical
~4
-13-
particle size fractions of the fluid under s-tud~, ac-
cording to the invention;
Fi~ure 5 shows a block-diagram of an apparatus for
carryin~ out the method for measuring parameters of
solid phase o~ slurries which is designed ~or measuring
concentration of solid phase and concentration of a
critical particle size fraction of solid phase with
the control of the length of received pulses of ultra-
sonic oscillations that passed through the fluid under
study and Lamb waves that passed throu~h a predetermined
distance alon~ the wall of a vessel containing the
fluid under study, according to t~e invention.
A method for measuring parameters of solid phase
of slurries according to the invention comprises the
following steps.
Ultrasonic oscillations 2 are formed and caused
to pass through a fluid 1 under study (~igure 1), the
wavelength o~ the oscillations bein~ commensurable
~ith the particle size of solid phase of the slurr~ 1
being studied. When the ultrasonic oscillations 2
propagate throu~h the slurry 1, their ener~ is ab-
sorbed and dissipated. Dissipation o~ the ultrasonic
oscillations prevail over absorption in case the
particle size i9 co~ensurable with the oscillations
~avelength. Generally speakin~, the amount of dampin~
of ultrasonic oscillations 2 at a fixed ~requency in
the slurr~ 1 under stud~ depends on concentration and
-14-
particle size of solid phase. It should be noted that
the ratio between absorption and dissipation of the
ultrasonic oscillations 2 depends on the fraction
of particles of solid ~hase whose size is co~ensurable
with the wavelength ol the oscillations 2 being used.
Gas bubbles is the disturbin~ factor in measuring
the value of attenuation of ultrasonic oscillations 2
in the slurry 1 bein~ studied. ~he process of damping
of the ultrasonic oscillations 2 at gas bubbles is
of a ;~anifest resonance nature~
~ ;ith an increase in frequency o~ the ultrasonic
oscillations 2 the amount of resonance-size bubbles
in the slurry 1 being studied substantially decreases,
and this amount is practicall~ reduced to zero at
frequencies of 5 MHz and higher. This is due to the
fact that thè resonance ~requency of gas bubbles decrea-
ses with a decrease in their size, and when the gas
bubble is dimi~ished to a predetermined limit, it i9
dissolved in water.
Therefore, the amount of damping of the ultrasonic
oscillations 2 at hi~h frequency, when they are caused
to pass through the ~luid 1 under study, substantially
depend only on solid particle size and solid phase
concentration, gas bubbles o~ non-resonance size in-
fluencin~ this amount only with a very hioh concentra-
tion of gaseous phase.
-15-
Lamb waves 3 are concurrently formed and caused
to pass along -the wall of a vessel containing the
fluid 1 under study. The amount of dampin~ of Lamb wa-
ves 3 in the vessel wall only ~epending on the âistance
they pass throu~h an~ concentration of solid phase
of the fluid 1 being studied. This amount does not
depend on solid phase particle size and concentration
of gas bubbles (because of their small mass).
After the ultrasonic oscillations 2 have passed
through the fluid 1 under study and the ~amb waves 3
have passed through a predetermined distance ~ along
the wall of a vessel co,ntaining the fluid 1 un~er study,
their amplitudes 4,5 are measured. Logarithms 6, 7 of
the measured amplitudes 415 are computed, and a dif-
ference 8 is computed between the computed logarithms.
A value 9 equal to
s -S1
S 3 - 2 9 wherein
S1
S1 is the logarithm of -the amplitude o~ the ~amb waves 3
that passed through a prede-termined dis-tance alon~
the wall of a vessel containiL~ the fluid 1 under study;
S2 is the logari~hm of the amplitude of the ultrasonic
oscillations 2 that passed through the fluid 1 under
study, is the concentration of the critical particle
size of solid phase of the slurry 1 under study, i.e.
the concentration ~ of particles of a comminuted ma-
terial having a size which is larger than a pre~set
critical size.
-16-
~ he amount of displacement of particles of a knoqn
size from the state of equilibrium or fro~ a steady
path of their movement under the action of external
factors in a slurr~ having a kno~n concentration ~
depends on their specific gravity. In case the specific
~ravit~ of a useful component of the fluid 1 under
study is known the amoun-t of deviation of particles of
the useful component can be determined, and the amount
of displacement of other particles of known size from
the state of equilibrium or a steady path of their
movement will characterize concentration of the useful
component in critical particle size fractions of the
slurry 1 under study.
~ or measuring this amount, acoustic currents and
radiation pressure of a sonic radiation 1~ are formed
in the fluid 1 under study under the action of power-
ful ultrasonic oscillations, ~he intensity of acoustic
currents and radiation pressure of the sonic radiation 10
is controlled by varying amplitude 11 of powerful ultra-
sonic oscillations. Thus, they can act upon various
fractions of the fluid 1 under study. ~hen a ratio 12
of a value S0 for the fluid under study without any
action of powerful ul-trasonic oscillations to the
same value S with the action of acoustic currents and
radiation pressure of the sonic radiation 1~ of a known
intensity is computed to characterize a concentration r
of the useful component in critical particle size frac-
tions of the slurry under study.
If concentra-tion of ~aseous phase has a volume
commensurable with concentration of solid phase which
is but very rare in practical applications, it is
preferable to carr~ out a double treatment of the fluid 1
under study with acoustic currents and radiation pres-
sure of the sonic radiation 10 to improve accuracy
of measurement of parameters of solid phase of slurries.
At the first stage, this is made before the fluid 1
under stud~ has been admitted to the zone where para-
meters of solid phase are measured so as to contribute
to a removal of gaseous phase into atmosphere, and at
the second stage, the same step is used for measuring
concentratio~ of the useful component in critical par-
ticle size fractions of the fluid under study as descri-
bed above.
Accuracy of measurement of concentration of solid
phase and concentration of critical particle size frac-
tions of solid phase of slurries with a high content
of gaseous phase may also be improved in another manner.
For that purpose, a change in the form of pulses
of the ultrasonic oscillations 2 that passed through
the fluid 1 under study and of the Lamb waves 3 that
passed through a predetermined disctance ~ along the
w311 of a vessel containing the fluid under study is
analyzed.
Under the action of inertia properties of the
.
-18-
slurry 1 under stud~, the ori~inal form of a pulse
is distorted. In case the emitted pulse is square,
the distortion manifests itself in a gradual rise of
the leading and decrease in the trailing ed~e. Inertia
properties of actual slurries depend substantially on
their concentration and gradi~ of solid phase of
slurries since the mass of particles of a cornminuted
material is several orders greater than the mass of gas
bubbles.
Particles of a comminuted material move together
v~ith liquid in the ultrasonic field. The character of
this movement depends on frequency of ultrasonic oscil-
lations and particle size; with an increase in particle
size, with a fixed ultrasonic oscillations frequency,
or with an increase in frequency, with a ~ixed particle
size of a comminuted material, the particles will lag
behind the movin~ liquid more and more. ~he difference
between inertia properties of a fluid under stud~
manifests itself in the form of a change in the form
of pulses of the ultrasonic oscillations 2 that passed
through the fluid 1 under study and of the ~amb waves 3
that passed through a predetermined distance along the
~all of a vessel containin~ -the fluid 1 under study
and depends on oscillations frequenc~, concentration
and grading of solid phase of slurries.
After the amplitudes 4,5 of pulses of the ultra-
-19-
sonic oscillations 2 and Lamb waves 3 have been measured,
two levels 13, 14 (Fi~ure 2) are formed at which to mea-
sure their len~-ths.
For that purpose, the received pulses are uuccessi-
vel~ limited by amplitude. Limitatio~ levels 15, 16
are chosen in such a manner that the ratio of the measu-
red amplitude 4,5 of the received pulses to the absolute
value of amplitudes of this value be a constant value.
After the measurement of leng~hs 17, 18 of the
ultrasonic oscillations pulses 2 that passed throu~h
the fluid 1 under study and ~amb waves ~ that passed
through a predetermined distance along the wall of a
vessel containing the fluid 1 under study at the two
levels 13, 14, differences 19, 20 between lengths
of each pulse at the two levels 13, 14 are computed.
The difference 20 between pulse lengths of the
Lamb waves that passed throu~h a predetermined distance e
along the wall of a vessel containing the fluid 1 under
study will characterize concentration of solid phase
of slurries.
A ratio 21 of the difference 19 between the
lengths 17, 18 of pulses of the ultrasonic oscillations 2
that passed through the fluid 1 under study to the
difference 20 between p~lse lengths of the ~amb waves 3
that passed through a predetermined distance e alOn6
the wall of a vessel containin~ the fluid 1 u~der study
represents concentration of a critical particle size
fraction of slurries.
~E34~:~Q
-2~-
. An apparatus for carryin~ out the method for measu-
ring parameters of solid phase and concentra-tion of
cri-~ical particle size of solid phase of slurries
comprises t~o measurement channels I and II (~i~ure 3).
The first measurement channel I consists of a
series circuit includin~ a tri~erin~ one-shot multi-
vibrator 22, a pulse ~enerator 23, an emitting ultrasonic
transducer 24, a receivi~g ultrasonic transducer 25, a
received pulse amplifier 26, and electronic switch 27
and a lo~ari-thmic converter 28. A series circuit con-
nected to the input of the triggerin~ one-shot multi-
vibrator 22 includes a one-shot delay multivlbrator 29,
a dif~ere-ntiator 3~, an amplitude limiter 31 and a
forminO one-shot multivibrator 32 havin~ its output
connected to the second input of the electronic switch 27.
~ he second measurement channel II consists of a
series circuit including a tri~gerin~ one-shot multivib-
rator 33, a pulse generator 34, an emitting ultrasonic
transducer 35 mounted on a first forming prism 36, a
receiving ultrasonic transducer 37 mounted on a second
forming prism 38, a received pulse ampli~ier 39, an
electronic switch 4~ and a logarith~ic converter 41.
To the input of the triggerin~ one-shot multi-
vibrator 33 is connected a series circuit including a
one-shot dela~ multivibtrator 43, an amplitude li-
miter 44 and a forming one-shot multivibtator 45 havin~
-21-
its output connected to the second input of the electro-
nic switch 4u.
h multivibtator 46 is connected to the inputs of
the tri~seriD~ one-shot multivibtators 22, 23. A subtrac-
tion unit 47 is connected between the lo~arithmic con-
verters 28, 41 of both measurement channels I,II, the
output of the subtraction unit being connected to one
input of a division unit 48 having a second input
to which is connected the output of the logarithmic
converter 41 of the second measurement channel II.
The emitting 24 and receivinæ 24 ultrasonic trans-
duoers of the first measurement channel I as well as
the forming prisms 36, 38 of the second measurement
channel II are mounted on a vessel 49 containing the
fluid 1 under study.
The multivibtator 46 ~enerates pulses, each pulse
tri~Oering; via the trig~ering one-shot multivibta-
tors 22, 33, the pulse generabors 23, 34 forming square
pulses filled wi~h electric oscillations at a pre-
determined frequency. ~he time during which the pulse
generators 23, 34 remain s~itched on, hence the len~th
of s~uare pulses formed thereby, will depend on the
len~th of pulses formed by the trigOering one-shot
multivibtators 22, 33~
The emitting transducers 24, 35, e.g. piezoelectric-
-type transducers, owin~ to the inverse piezoelectric
-22-
effect, transform the electric oscillations into elastic
ultrasonic oscilla-tions of a fluid with which they come
in contact.
~ he first emittin~ transducer 24 is mounted
directly on the wall of the vessel 49 containing the
fluid 1 under study and forms in the wall material lonOi-
tudinal ul~rasonic oscillations 2 which are radiated
into the slurr~ 1 under study.
~ he wavelength of the ultrasonic oscillations 2
emitted by the emittin6 ultrasonic transducer 24 is
chosen to be o~ the same order (commensurable with) as
the particle size of solid phase of the fluid 1 under
study. It should be noted that frequency of the ultra-
sonic oscillations thus formed should be such (high
enou~h) that there should be no Oas bubbles of resonance
size ~or such frequenc~. In this case the amount of
damping of the ultrasonic oscillations 2 that passed
through the fluid 1 under study is substantiall~ deter-
mined onl~ b~ the size of solid phase particles and
their concentration.
For evaluation of concentration of solid phase,
the amount of dampinO of the Lamb waves 3 that passed
through a predetermined disbance e alo~ the wall of
the vessel 4~ containin~ the fluid 1 under study is
~leasured. For formin~ the Lamb waves 3, the emitti~g
ultrasonic transducer ~5 is mounted on the forming
prism 36 which is secured to the wall of the vessel 49
~ ~8~5 ~
containin~ -the fluid 1 under stud~.
~ he angle at whIch the ultra~onic oscillations 2
are directed into the wall of the vessel 49 containing
the fluid 1 under study throu~h the forming prism 36
is chosen in such a manner as to ~enerate the Lamb
waves 3 in the wall.
~ he~n the ~amb waves 3 propaæate thrGugh the wall
o~ the vessel 49 containin~ -the fluid 1 under study,
the amount of their dampi~ is only determined by
concentration of solid phase of slurries.
The receiving ultrasonic transducer 25, owin~ to
the direct piezoelectric effect, transforms the ultra-
sonic oscillations 2 that passed throu~h the fluid 1
under study into electric oscillations. ~he same process
occurs in the receiving ultrasonic transducer 37 for
the ~amb waves 3 that passed through a predetermined
distance alon~ the wall of the vessel 49 containing
the fluid 1 under study.
The received pulses are amplified in the ampli-
fiers 26, 39 and are fed to the electronic switches 27, 40.
Pulses formed by the multivibrator 46 trigger the
one-shot delay multivibtators 29, 42 which ~enerate
square pulses, e.~. positive pulses9 the length o~
which is equal to the minimum time duri~ which the
ul~rasonic oscill~ions 2 propagate through the fluid 1
under study and minimum time durin~ which the Lamb
waves ~ pass through a predetermined dis-tance alon~
5 ~ ~
-24-
the ~Jall of the vessel 49 co~taining the fluid 1 un~er
study, respectively. The differentiators ~, 43 diffe-
reltiate the pOSib' ve square pulses formed by the
one-shot delay multivibta-tors 29, 42, these pulses
bein~ transformed into two successive short positive
and ne~ative pulses. ~he amplitude limi-ters 31, 44 let
throu~h only the second, negative pulse wilich will
trigger the one-shot formi~ multivibrators 32, 45.
The length of pulses formed by the forming one-shot
rnultivibbators 32, 45 is chosen in such a manner that
it should correspond to the infomative part OL pulses
of the ultrasonic oscillations 2 that passed through
the fluid 1 under study and Lamb waves 3 that passed
through a predetermined distance e alo~g the wall of
the vessel 49 containin~ the fluid 1 under study.
The pulses formed by the formin3 one-shot multi-
vibrators 32, 45 gate open the electronic sv,~itches 27, 4
which will pass throu~h only the informatice part of
pulses of the ultrasonic oscillations 2 -that passed
through the fluid under study and the Lamb waves 3
that passed -throuOh a predetermined distance e alo~
-the wall of the vessel 49 containir~ the fluid 1 under
study.
~ he amplitude of the Lamb waves 3 that passed
throu~h a predetermined distance along the wall
of the vessel 49 containing the fluid 1 un~er study
will characterize concentration of solid phase of a
slurry.
-25-
'~he logarithmic converters 28, 41 c~mpute lo~arithms
of amplitudes of the sigrlals that passed -throu~h the
electronic swi-tches 27, 4~.
The subtraction unit 47 computes the difference
between logarithms of -the ~easured amplituaes, and
the division unlt computes the value of S.
An apparatus for carrying out the method for
measuring parameters of solid phase of slurries, which
allows concentration of solid phase, concentration
of a critical particle si.ze fraction and concentration
of a useful component in critical particle size frac-
tions of a fluid under study ~o be measured also compri-
ses two measureme~t channels (Figure 4).
The first measurement channel consists of a series
circuit including a pulse generator 23, an emitting
ultrasonic transducer 24 mounted on a wave ~uide 5~,
a receivi~ ultrasonic transducer 25 mounted on a wave
guide 51, a received pulse amplifier 26,and a pulse
expander 52r
~ he second measurement channel consists of a
series circuit including a pulse æenerator 34, an
emitti~g ultrasonic transducer 35 mounted on a formin~
prism 36, a receivin~ ultrasonic transducer 37 mounted
on a forming prism 38, a received pulse amplifier 39,
and a pulse expander 53. The received pulse amplifiers 26
and 39 of the first and second measurement channels
com~rise logarithmic amplifiers.
,, r~ ~ rr~ ~
-2~-
To the outputs of the pulse e~panders 52, 53
of both measureluent chanrlels are connected in~uts of a
subtraction unit 47 havin~ its output connected to
one of the inputs of a division unit having its second
input con~ected to the ou~put of the pulse expander 53
of the second measurement chanrlel.
The output of a first division unit 48 is connected
to the second inputs of first 27, second 4u, third 54
and fourth 55 electronic switches each havin~ its
first input connected, via a first 56, second 57,
t~lird 58 and fourth 59 delay lines, to the first four
outputs of a decoder 6~ ~Jhich are also connected to
the inputs of an OR æate 61 havinO its output which
is conneoted, via a fifth 62 and a si~th 63 dela~
lines, to the inputs of the pulse ~enerators 23, 34
of both measurement channels.
To the second, third and fourth out~uts of the
decoder 6~ are con~ected first 64, second 65 and third 66
one-shot multivibra-tors havin~ -their ou-tputs connected
to the inputs of a first OR ~ate 67 havinO its output
which is connected, via a third 3enera~or 68, to
a th~rd emittin~ ultrasonic transducer 69.
To the outputs of the first 27, second 40, third 54
and fourth 55 electronic suitches are connected the
first inputs of a first 7~, second 71, third 72 and
fourth 73 amplitude detectors havin~ their second
inputs connected to the ei~hth output of -the decoder 6
-27-
and the ou-tputs connected to the first inputs of fi~th 74,
sixth 75, seventh 7~ and eighth 77 electronic switches.
To the output of the fifth el_ctronic sv~itch 74
is connected the first input of a second division
unit 78 havin~ its second input connected to the
outpu-ts of the sixth 75, seventh 76 anâ eiOht 77 electro-
nic svJitches having their second inputs connected, via
a f ~ th 79, sixth 8~ and seventh 81 one-shot multi-
vibrators, to the fifth, sixth and seventh outputs
of the decoder 6~ and to the inputs of a second OR
~a-te 82 havin~ its output connected, via a fourth one-
-shot multlvibtator 83, to the second input of the
fifth electronic switch 74~
To the input of -the decoder 6~ is connected a
counter 84 which is con~ected to the one-shot multi-
vibrator 46.
The third emitting ultrasonic transducer 69 is
mounted in the top part of the vessel 49 containing
the fluid 1 under study, in -the bot-tom part o~ which
there are provided wave ~uides 5~, 51 supportinO the
emittin~ 24 and receivinO ?5 ultrasonic transducers
of the ~irst measurement chan;.el and also the forminO
prisms 36, 38 supportin3 the emittin~ 35 and receiving 38
ul-trasonic transducers of the second measurement
channel.
The forming prisms 36, 38 may also be mounted
on a measurement plate covering a lon~ritudinal aperture
r~
--2~--
in the wall o~ the ves~el 49 containing the fluid 1
under study.
The apparatus for measurinJ parameters of solid
phase of slurries shown in ~i~ure 4 ~unctions in
the following manner.
The multivibrator 46 generates square pulses which
go to an electronic pulse distribltor built around
the counter 84 end decoder 6V havin~ eight outl)uts.
Thus one control cycle COllSi sts of eight steps. At
the first step, a pulse from the ~irst output o~ the
decoder 6~ will pass throu~h the OR gate 61, fifth 62
and sixth 63 delay lines to trig~er the first '23 and
second 34 pulse ~enerators. To reduce interference
between the measurement channels, the pulse delay time
in the delay lines 62, ~3 is chosen in such a manner
as to ensure a time shift between the periods of star-
ting the first 23 and second 34 pulse genera~ors which,
when triggered, will ~enerate trains of hi~h-frequency
electric oscillations at a predetermined frequency
and pulse length.
~ he emittin~ ultrasonic transducers 24, 35, e.g.
of the piezoelectric type, trans~orm the electric
signal into elastic oscillations of a medium with
which they come in contact.
~ he first emittin~ ultrasonic transducer 24
emits, through tne first wave guide 5~ ultrasonic
oscillations 2 intp the ~luid 1 under study in the
$~
-29-
vessel 49 in the direction to~ard the first receivin~
ultrasonic transducer 25 mounted on the second wave
Ouide 51. The second emittin~ ultrasonic transducer 35
forms, throu~h the first formin~ prism 36, in the
wall of the vessel 49 (or measurement pla-te) the Lamb
waves 3 which, havinæ passed throu~h the second forming
prism 38, are received by the second receiving ultrasonic
transducer 37.
The amount of dampin~ of the high-frequency ultra-
sonic oscillations 2 vihen they pass from the first
emittin~ ultrasonic transducer 24 to~ard the first
receiving ultrasonic transducer 25 substantially depends
only on particle size of solid phase and their concentra-
tion.
When the Lamb waves 3 pass throu~h a predetermined
distance e alo~g the v~all of the vessel 49 containin3
the fluid 1 under study, the amount of their dampin,
onl~ depends on concentration of solid phase of slurries.
The ultrasonic (elastic) oscilla~ions 2 that passed
through the fluid 1 under study and -the Lamb waves that
passed throuOh a predetermined distance along the
wall of the vessel 49 containing the fluid 1 under study
are transformed into electric oscilla~ions b~ the
receivin~ ultrasonic transducers 25, 37.
The high-frequency electric oscillations are
al~plified on logarithmic scale and detected in loæarith-
mic amplifiers 26, 39. As the len~th of the formed
-3~-
pulses is short, it is expanded in the pulse expanders 52,53
v~ithout chan3es in the amplitude.
The difference between loOarithms of the received
si~nals i5 determined in the subtraction unit 47, and
the ~irst division unit 48 computes the value of S.
~ he amplitude of the Lamb waves 3 that passed
through a predetermined distance ~ along the wall of
the ~essel 45 containinO~ the fluid 1 under study will
characterize concentration of solid phase of the fluid 1
under study, and the value of S is the concentration
of a critical particle size fraction of the slurr~
under study.
. A pulse from the first output of the dec~der 6~
will pass throu~h the first delay line 5~ to ~ate open
the first electronic s~itch 27. Its delay time in the
first delay line 56 is determined by the time of propa-
~ation of the ultrasonic oscillations in the fluid 1
under study and the ~amb waves 3 in the wall of the
vessel 49 containin~ the iluid 1 under study, and this
dela~ time is chosen in such a manner so to ~ate open
the first electronic switch 27 by the moment the value
of S is computed in the division unit 48.
The first amplicude detector 70 ~Jill hold ("store")
the value of SO.
The second, third and fourth control steps are
effected similarly to the ~irst step since the second,
~ ~ 4~ ~
-31-
third and fourth pulses from the second, third and
fourth outputs, respectively, of the decoder 60 will
also trigger the pulse genera~ors 23~ 34 Vi3 the OR
,ate 61.
At the same time, each of these pulses will tri~Oer
the first 64, second 65 and third 66 one-shot multi-
vibrators v~hich, via the OR Oate 67, will trig3er the
-third ~e~erator 68 formin~ powerful electric oscilla-
tions v~hich are transformed by the third emitting ultra-
sonic transducer 69 into elastic oscillations of fluid.
Acoustic currents and radiation pressure of the
sonic radiation 10 are 3enerated under the action of
the powerful ultrasonic oscillations ~ thus formed to
cause displacements of solid phase particles in the
fluid 1 under study away from the third emitting ultra-
sonic transducer 69 in the direction toward the wall
of the vessel 49 on which are mounted the formi~ prisms 36,38
of the second measurement channel.
The displacement of solid phase particles ~ill
cause a chcmge in their distribution by size and
concentration in the zone adjacent to the wall of the
vessel 49 on which are mounted -the formi~ prisms 36,~8
of the second measurement chanflel and also in the
zone between the ~Jave Suides 509 51 of the first measu-
rement channel.
T~e amount of redistribution of the~e paremeters
for particles of identical size located at a pred~ter-
~845
--32--mined distance from the third emittinO~ ultrasonic trans-
ducer 69 depends only on specific gravi-ty of the par-
ticle material.
In practice, the material of the particles is
in the form of a combination of several components
one of which is a useful component the concentration
of which should be measured.
Since the specific gravity of the useful component
is known, the amou~t of displacement of particles of
a known size consistin~ of -this component onl~ under the
action of acoustic currents and radiation pressure of
the sonic radiation 1~ of a known intensit~ is deter-
mined analytically or by way of experiments.
The intensit~ of action of these ~actors will
change upon a change of either amplitude or length
when powerful ultrasonic oscillations formed by the third
emitting ultrasonic transducer 69 are applied.
In case of the pulsed nature of action of power-
ful ultrasonic oscillat~ons at â fixed amplitude the
effect of the acoustic currents and radiation pressure
of the sonic radiation 1~ formed thereby upon a particle
of solid phase of a slurry depends on the pulse length.
~ he length of pulses formed by the first 64,
second 65 and third 66 one-shot multivibrators is
chosen in such a manner that the effect of the acoustic
currents and radiation pressure of the sonic radiation 10
~ e sufficient to cause a displacement of particles
of three, and generally, more than three critical
particle size fractions of solid phase of slurries.
The computer value of S for each case (SI, SII, S
is fed, via the second 40, third 54 and fourth 5~
elcctronic switches ~ated open by pulses fed from the
second, third and fourth outputs of the decoder 60 and
aela~ed in the delay lines 57, 589 59, to the second,
third and fo~th amplitude detectors 71, 72, 73 which
will hold the amplitudes. The dela~ time in the delay
lines 57, 58, 59 is chosen bearin~ in mind the same
considerations as thosé for the dela~ line 56.
Pulses fed from the fifth, sixth and seventh outputs
of the decoder 6~ ~iill gate open, via the fifth, sixth
and seventh one-shot multivibrators 79, 8~, 81, the
sixth, seventh and eighth electronic switches 75, 76, 77.
Each of the pulses goin~ from the fifth, si~th and
seventh outputs of the decoder 6~ will ~ate op~n, via
the second OR gate 82 and the fourth one-shot multi-
vibrator 83, the fifth electronic switch 74. The values
of SO and SI, SO and SII, SO and SIII are fed pair~ise
to the second division unit where concentration ~ of
-the useful component is computed:
r~ ~ , i = I, II, III.
O
Still another embodiment of the apparatus for
measuring parameters of solid phase of slurries is
~l~{~
-34-
shown in Fi5ure 5 and also co~nprises two measurement
channels.
The first channel comprises a series circuit in-
cluding a pulse generator 23, a power amplifier 85,
and an emitting ultrasonic transducer 24 and also a
series circuit including a receivin~ ultrasonic trans-
ducer 25, a received siOnal amplifier 26, an electronic
switch 27, a logari-thmic converter 28, a delay line 56,
a first ampli-tude li~iter 31~ a first circuit B6 for
controlling a clock 87, and a unit 88 for computin~
the difference between lengths of pulses at different
limitation levels.
A blockin~ oscillator 89 is connected bet~een the
pulse generator 23 and electronic switch 27 and a unit 9
.for selecting limitation level is connected between
the lo~arithmic converter 28 and the li~iter 31.
~ o the output of the amplitude limiter 31 are con-
nected a second amplitude limiter 44, a second circuit
for controllin~ a clock 92 and the clock ~2 formin~
a series circuit, the output of the clock being con-
nected to the cecond input of the computin~ unit 88.
Between the logarithmic converter 28 and the second
amplitllde limiter 44 is connected a second unit 93 for
selectinO limitation level.
~ he second measurement channel comprises a series
circuit includin~ a pulse ~enera-tor 34, a power ampli-
fier 94, an emittin6 ultrasonic transducer 35, a re-
-35-
ceiving ultrasonic transducer 37, a received pulse
amplifier 39, an electronic sv~i-tch 40, a lo~ari-thmic
converter 41, a delay line 57, a third amplitude li-
miter 95, a third circuit 95 for controlling a clock 979
the third clock 97 and a unit 98 for computing the dif-
ference betv~een pulse lengths at different lil~ita-tion
levels.
A blockin~ oscilla-tor 99 is provided between the
pulse genera-tor 34 and electronic switch 4~. A third
unit 1~ for selecting limitation level is provided
between the logarithmic converter 41 and third amplitude
limiter 95. A series circuit including a fourth ampli-
tude limiter 101, a fourth circuit for controlling a
clock 1~3 and the fourth clock 1~3 is providad between
the third amplitude limiter 95 and the subtraction
unit 98.
A fourth unit 1~ for selectin~ limitation level
is provided between the lo~arithmic converter 41 and
fourth ampli~ude limiter 101. h subtraction unit 47,
havin~ an output connected to one input of the division
unit 48 having its second input connected to the output
of the unit 98 for computin~ the difference between
the pulse lengths at different li~l~itation levels,
is provided between the units 88 and 98 for computing
the difference between pulse lengths at different limi-
tation levels. A switching circuit 105 havi~g an in-
put to which is connected a multivibratcr 47 is connected
~a~s:~
-3~-
bet~een the pulse ~enerators 23 and 34. The emitting
ultrasonic transducer 35 is mounted on a formin~ prism 36,
and -the receivin~ ultrasonic transducer 37 is mounted
on a formin~ prisrn 38. A measurement plate 1J6 covers
a lon~itudinal aperture 1~7 in the wall of a measurement
vessel 49.
~he apparatus functions in the followin~ manner.
~ he pulse generators 23, 34 form square pulses
filled with sinusoidal oscillations. ~he frequency of
oscillations formed by the pulse ~enerator 23 in the
first measurement channel I is cnosen in such a manner
that the wavelength of trlese oscillations be commensu-
rable with particle size of solid phase in the fluid 1
under stud~.
The sinusoidal electric oscillations amplified
in the power amplifiers 85, 94 are transformed into
ultrasonic elastic oscillations of the medium and are
emitted by the emitting ultrasonic transducer 24 into
the fluid 1 under study and by the emit~ing ultrasonic
transducer 35, via the forming prism 36, into the walls
of the vessel 49 or into the measurement plate 106 co-
vering the longitudinal aperture 107 of the measurement
vessel 4~ containing the fluid 1 under study, in which
the ~a~b waves 3 are induced.
~ he blocking oscillators 89, 99 are trig~ered
by the leading ed~e of square pulses generated by the
pulse generators 23, ~4, and pulses formed thereby
-3i-
will ~ate open the electronic switches 27, 40 which
will let throu~h, during a selected -ti~e ,in-terval, sio-
nals from th~ received si~nal amplifiers 26,39.
~ he logari-thmic converters 28, 41 for~ pulses havi~
ampli-tudes proportional to the logarithm of amplitude
of the pulses that passed through the electronic
s~itches 27, 40.
The received pulses ~o, via -the delay lines 56, 57,
to the variable amplitude limiters 31, 9~. ~he pulse
arrival delay time depends on characteristics Oî the
units 90 and 100 for selecting limitation level which
will form limitation level in accordance with the cur-
rent value of amplitude of the received pulse and
pre-set values of ratios of the ampli-tude of the received
pulse to the limitation level. ~herefore~ the absolute
value of limitation level will chan~e proportionally
with the amplitude of the received pulse, the ratio
of this level to the pulse amplitude remainin~ unchan-
~ed. This facility makes it possible to avoid the in-
fluence of fluctuations of damping of the ultrasonic
oscillations 2 caused by various factors ~hen they pass
throu,h the fluid 1 an~ the influence of fluctuations
of damping of the Lamb waves 3 that passed through a
pre~etermined distance e along the ~iall of the vessel 49
co~taining the fluid 1 under stud~ on the lenæth of the
received pulse at the formed measurement levels.
~ he variable amplitude limiters 44, 101, in combi-
nation with the units 93, 104 for selecti~ limitation
~ 4S~
~38-
levels, ~ill form a second level of limitation of the
received pulse. The clock control circuits 8~, 91, 96,
1~2 v~ill trig~er the clooks 87, 92, 97, 1~2 by the
moment the limitation of ~he amplitude of the received
pulse~ is started and will disable them when the ampli-
tude of these pulses will start ~ecreasing.
The first unit ~ for computin~ the difference bet-
ween the pulse len~ths at dlfferent limitation levels
will compute the difference cC between lengths of a
pulse of the ultrasonic oscillations 2 that passed
-throu~h the fluid 1 under st~dy at the formed measure-
ment levels, and the second unit 98 for computing the
difference between len~ths of pulses at different li-
mi-tation levels will compute the difference ~ of
lengths of pulses of the Lamb ~aves 3 that passed along
the wall of -the vessel 49 containin~ the fluid 1 under
stud~- The diff'erence c~ -J3 is computed in the sub-
traction unit 47.
~ he d:ivision unit 48 ~Jill compute the value of S0
which characterizes concentratio~ of a critical par-
ticle size fraction of solid phase of a slurry: S
~ he value of ~0 is transformed into a si~nal of a
s-tandard form and value in scaling uni-t 104.
~ herefore 9 the method and apparatus for meas~rinO
parameters of solid phase of slurries accordin~ to
the invention make it possible to measure by a non- -
-contact method concentration of solid phase, concentra-
tion of a critical particle size fraction of solid phase
-39-
and concentration of a useful component in critical
particle sizc fractions in a slurry un~er stud~ without
preliulinary removal of gaseous phase from the slurry
usin~ mechanical means. All this contributes to an
improvement of accuracy and reliability of measurements
and also to a reduction of tho cost of equipment for
measurin~ parameters of solid phase of slurries and ope-
ration cost of such equipment.
