Ultrasonic methods and apparatus for separating materials in a fluid mixture

An efficient method of separating a first material from a second material in a fluid mixture is provided. The fluid mixture of interest is caused to flow through two different sonic wave fields. In one field, the sonic waves travel in a direction perpendicular to the direction of flow of the fluid mixture. In the other field, the sonic waves travel in a direction parallel to the direction of flow of the fluid mixture. The overall effect of the sonic waves in these two fields is to irreversibly break any molecular bonding between a substantial portion of a first material and a second material in the fluid mixture. In one embodiment, the perpendicular-directed sonic waves are cavitation waves and the parallel-directed sonic waves are standing waves.

TECHNICAL FIELD 
This invention relates to sonic and ultrasonic methods and apparatus for 
separating a first material from a second material in a fluid mixture. It 
is particularly useful for separating hydrocarbons, organics, suspended 
solids and inorganic materials from a fluid solution. 
The term "sonic" is used in this description and in the appended claims in 
a generic sense and is intended to include all sonic, ultrasonic, 
supersonic and hypersonic type vibrations and pressure waves. 
BACKGROUND OF THE INVENTION 
The separation of hydrocarbons, organic materials, suspended solids and 
inorganic materials from a fluid solution has been practiced for many 
generations. Many of these practices include, but are not limited to: 
applied heat or pressure or both; 
addition of chemicals to oxidize, reduce and neutralize electrical 
unbalance; 
addition of emulsion breakers; 
use of centrifugal forces; 
flocculating; 
filtrating; 
and similar processes. 
These previously used or proposed processes suffer from one or more of the 
following disadvantages: 
heat driven chemical reactions; 
relatively long processing times; 
complicated and costly equipment; 
high energy consumption; 
complicated operating procedures; 
limited versatility; 
require extensive maintenance; 
short useful lifetimes; or 
high cost per volume processed. 
In general, it would be desirable to have separation methods and apparatus 
which can easily and efficiently separate different materials with a 
minimum of processing time. It would also be desirable to provide a method 
which is economical in operation and requires a minimum amount of fixed 
equipment. 
SUMMARY OF THE INVENTION 
The present invention provides a relatively easy and uncomplicated, yet 
very efficient method of separating a first material from a second 
material in a fluid mixture. In particular, the fluid mixture of interest 
is caused to flow through two different sonic wave fields. In one field, 
the sonic waves travel in a direction perpendicular to the direction of 
flow of the fluid mixture. In the other field, the sonic waves travel in a 
direction parallel to the direction of flow of the fluid mixture. The 
overall effect of the sonic waves in these two fields is to break any 
molecular bonding between a substantial portion of a first material and a 
second material in the fluid mixture. 
In one embodiment, the perpendicular-directed sonic waves are cavitation 
waves and the parallel-directed sonic waves are standing waves. The 
cavitation waves provide a homogenizing action whereby the material 
particles are broken up and more or less uniformly dispersed. The standing 
waves, on the other hand, cause an agglomeration or gathering together of 
like particles at the nodes and antinodes of the of the standing waves. 
These wave actions serve to break or sever any molecular bonding between 
the different materials. And this process is irreversible. The treated 
components do not recombine and may be physically separated by known 
weight-sensitive separation techniques. For example, the treated mixture 
may be supplied to an appropriate settling tank and allowed to settle. In 
this case, the particles of the heavier material will fall to the bottom 
of the tank, while the particles of the lighter material will rise to the 
top. 
For a better understanding of the present invention, together with other 
and further advantages and features thereof, reference is made to the 
following description taken in connection with the accompanying drawings, 
the scope of the invention being pointed out in the appended claims.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Referring to FIGS. 1 and 2, there is shown sonic separator apparatus 10 for 
use in separating a first material from a second material in a fluid 
mixture. This sonic separator apparatus includes a generally-rectangular 
trough-like channel structure 11 which provides a flow channel for the 
fluid mixture. Channel structure 11 has an inlet end wall 13 and an outlet 
end wall 14. As seen in FIG. 2, the bottom of the channel structure 11 has 
a step construction with the outlet end portion 15 being at a lower 
elevation than the inlet end portion 16. The bottom portion 15 is 
connected to the bottom portion 16 by a vertical riser portion 17. The 
front and back sides of the channel structure 11 are solid metal walls and 
the top of the channel structure 11 is open. A metal flange 12 runs 
completely around the top edge of the channel structure 11 and, as seen in 
FIG. 2, extends outward from the channel structure 11. Flange 12 may be 
used for mounting and supporting the channel structure 11. 
The bottom and side walls of channel structure 11 are made of stainless 
steel having, for example, a 10-gage thickness. Thus, the channel 
structure 11 is rigid in nature and typically will have a length of some 
four to five feet. 
A wedge-shaped stainless steel header box 24 is welded to the inlet end 
wall 13 with the wider opening in the header box being aligned with a 
corresponding opening in the lower portion of end wall 13, such opening 
extending laterally across the width of the end wall 13. The narrow end of 
header box 24 is provided with a circular pipe portion 25 which is adapted 
for coupling to a fluid supply pipe 27. A sound velocity sensor 26 is 
connected between header pipe portion 25 and the fluid supply pipe 27 for 
measuring the velocity of sound waves in the fluid mixture entering 
through supply pipe 27. 
A second wedge-shaped stainless steel header box 28 is connected to the 
channel structure bottom portion 15 in a downward extending manner at the 
outlet end wall 14. The shape of this outlet header box 28 is best seen in 
FIG. 4. The opening in the wider upper end of header box 28 is aligned 
with a corresponding opening in the bottom portion 15 of the channel 
structure 11. The lower end of outlet header box 28 is provided with a 
circular pipe portion 29 which is adapted to be coupled to an appropriate 
discharge pipe (not shown). 
The fluid mixture flowing through channel structure 11 is indicated by 
reference number 30 in FIG. 2. This fluid mixture is supplied to the inlet 
header box 24 by the supply pipe 27. It enters the channel structure 11 by 
way of the inlet header box 24 and flows along the channel structure 
bottom portion 16, downward along the riser portion 17, across the channel 
structure bottom portion 15 and into the outlet header box 28. The fluid 
mixture 30 leaves the channel structure 11 by way of outlet header box 28 
and whatever discharge pipe is connected to header outlet pipe 29. 
The sonic separator apparatus 10 further includes a first sonic transducer 
mechanism 18 coupled to the channel structure bottom portion 16 for 
producing in the fluid mixture 30 first sonic waves which travel in a 
direction perpendicular to the direction of flow of the fluid mixture. In 
the illustrated case, the sonic vibrations emitted by transducer mechanism 
18 travel in a vertical direction toward the upper surface of the fluid 
mixture 30. As best seen in FIG. 3, the transducer mechanism 18 of the 
present embodiment is comprised of three individual transducers 18a, 18b 
and 18c which are mounted in a side-by-side manner across the width of the 
channel structure 11. The upper surfaces of these transducers 18a, 18b and 
18c are silver soldered to the underside of the channel structure bottom 
portion 16. Each individual transducer, for example, the transducer 18a, 
is comprised of a laminated E-shaped core piece 19 having a coil 20 of 
insulated electrical wire wrapped around the middle leg of the core piece 
19. Energizing the coil 20 with electrical alternating current causes the 
core piece 19 to vibrate back-and-forth in a vertical direction. 
The sonic separator apparatus 10 also includes a second sonic transducer 
mechanism 21 which is coupled to the underside of the channel structure 11 
for producing in the fluid mixture 30 additional sonic waves which travel 
in a direction parallel to the direction of flow of the fluid mixture 30. 
In the present embodiment, this second transducer mechanism 21 is attached 
to the vertical riser portion 17 (FIG. 2) which connects the two 
horizontal bottom portions 15 and 16 of the channel structure 11. The 
transducer mechanism 21 is oriented to emit sonic vibrations in a 
horizontal direction toward the outlet end wall 14. As seen in FIG. 1, the 
transducer mechanism 21 is comprised of three individual transducers 21a, 
21b and 21c which are mounted in a side-by-side manner across the width of 
the channel structure 11. Each of the transducers 21a, 21b and 21c has a 
laminated E-shaped core piece 22 and an electrical coil 23 which is 
wrapped around the middle leg of the core piece 22. The core pieces 22 are 
silver soldered to the riser portion 17. 
In the majority of applications, the sonic transducer mechanisms will be of 
the magnetostrictive type, as shown. For those applications where less 
sonic power needs to be applied to the fluid mixture being treated, 
piezoelectric type transducers may be used. 
The sonic separator apparatus 10 also includes a first transverse weir 
member 32 located in the inlet end portion of the channel structure 11 
downstream of the first sonic transducer mechanism 18. Weir member 32 
functions as a dam structure for controlling the flow of the fluid mixture 
30. The vertical position of weir member 32 is adjustable for adjusting 
the depth of the fluid mixture seen by the first sonic transducer 
mechanism 18. 
The construction of the elements associated with weir member 32 are best 
seen in FIG. 3. As there seen, weir member 32 is suspended from an 
overhead support beam 34 which is rigidly attached to the side walls of 
the channel structure 11. More particularly, the weir member 32 is 
supported by a drive shaft 33 having a threaded (worm gear) lower portion 
which engages a mating threaded passageway in the weir member 32 (see FIG. 
2). Drive shaft 33 extends upwardly through a passageway in the support 
beam 34 and is retained therein by upper and lower retaining clips 35. 
Drive shaft 33 is free to rotate in the support beam passageway. An 
electric motor 36 is connected to the upper end of drive shaft 33 and, 
when energized, serves to rotate the drive shaft 33. Depending on the 
direction of rotation, this rotation causes a raising or lowering of the 
weir member 32. Vertically-extending guide shafts 37 and 38 (FIG. 3) help 
stabilize the movement of the weir member 32, these guide shafts 37 and 38 
being slidably located in appropriate passageways extending through the 
support beam 34. 
An adjustable fluid flow guide member 40 is located a short distance away 
from the vertical riser portion 17, on the downstream side thereof The 
location of the guide member 40 along the longitudinal center line of the 
channel structure 11 may be adjusted by loosening the mounting nuts 41 and 
sliding the guide member 40 to the right or left, as may be needed. The 
purpose of the guide member 40 is to cause the fluid mixture 30 to flow 
downward along the inner wall of the riser portion 17, with the fluid 
mixture 30 in contact with such inner wall. This provides good sonic 
coupling of the transducer 21 vibrations into the fluid mixture 30 located 
downstream of the riser portion 17. 
The sonic separator apparatus 10 further includes a second transverse weir 
member 50 (see FIGS. 2 and 4) which is located in the outlet end portion 
of the channel structure 11 downstream of the second sonic transducer 
mechanism 21. The vertical position of this second weir member 50 is 
adjustable for adjusting the depth of the fluid mixture 30 seen by the 
second sonic transducer mechanism 21. The structure for providing this 
vertical position adjustment is generally, but not entirely, similiar to 
the corresponding structure for the first weir member 32. In particular, 
the second weir member 50 is suspended from a moveable support beam 52 by 
means of a threaded drive shaft 51. An electric motor 53, when energized, 
causes rotation of the drive shaft 51 to cause a raising or lowering of 
weir member 50, depending on the direction of rotation of motor 53. 
Vertical guide shafts 51a and 51b help maintain the proper orientation for 
the weir member 50 as it is raised or lowered. 
A mechanism is also provided for adjusting the longitudinal position of the 
second weir member 50 so as to change the distance between it and the 
second transducer mechanism 21. This adjustment is significant because the 
weir member 50 is also used as a reflector for the horizontally-traveling 
sonic waves emitted by the transducer mechanism 21. This longitudinal 
position adjustment is provided by a threaded drive shaft 57 having one 
end longitudinally fixed in a transverse support beam 56 which is firmly 
attached to the sidewalls of the channel structure 11 and having the other 
end extending into a threaded passageway in a tubular sleeve member 58 
which is securely attached to the moveable transverse support beam 52 The 
support beam 52 for the weir member 50 is slidably supported by a pair of 
horizontal guide shafts 54 and 55 which are securely attached at one end 
to the fixed support beam 56 and are securely attached at the other end to 
the outlet end wall 14 (see FIG. 1). An electric motor 59 is mounted on 
the fixed support beam 56 and is coupled to the horizontal drive shaft 57 
so that when the motor 59 is energized, it rotates the drive shaft 57 
which, in turn, causes the slidable support beam 52 to slide along the 
guide shafts 54 and 55, either in the direction of the transducer 
mechanism 21 or in the direction of the outlet end wall 14, depending on 
the direction of rotation of the drive shaft 57. 
Referring to FIG. 5 of the drawings, there is shown a block diagram of 
representative electrical circuits that may be used with the sonic 
separator apparatus 10 of FIGS. 1-4. For sake of cross-reference, the 
sound velocity sensor 26 of FIG. 5 corresponds to the like-numbered 
element shown in FIGS. 1 and 2 and connected between the inlet pipe 
portions 25 and 27. Sound velocity sensor 26 senses the velocity of sound 
waves in the fluid mixture 30 as it enters the channel structure 11. 
Sensor 26 produces an output signal which is indicative of such sound wave 
velocity. Sensor 26 may be, for example, a known type of sonic sensor for 
measuring the travel time of a sonic pulse over a known distance in the 
fluid mixture 30. 
Transducers 18 and 21 of FIG. 5 represent the like-numbered sonic 
transducer mechanisms shown in FIGS. 1-3. 
The electrical circuits shown in FIG. 5 further include a first variable 
frequency electrical wave generator 60 for energizing the sonic 
transducers 18. The electrical wave produced by generator 60 is supplied 
to transducers 18 by way of amplifier circuit 61. The power level of the 
wave supplied to transducers 18 can be adjusted by adjusting the gain of 
amplifier 61. The initial frequency for the electrical sine wave signal 
produced by generator 60 should be somewhere in the range of 15,000 Hertz 
(cycles per second) to 40,000 Hertz. A good choice for this initial 
operating frequency is 20,000 Hertz, which is slightly above the normal 
human hearing range. The generator 60 should be capable of varying its 
operating frequency by plus or minus 100 Hertz or more in response to 
signals from the sound velocity sensor 26. 
Generator 60 is responsive to the output signal produced by the sound 
velocity sensor 26 for adjusting the frequency of the generated electrical 
wave for minimizing any change in wavelength in the fluid mixture 30 of 
the sonic waves produced by transducers 18. As will be explained, the 
wavelength of the sonic waves in the fluid mixture is of considerable 
importance for obtaining optimum performance of the sonic separator 
apparatus 10. For any given set of physical parameters, there is an 
optimum wavelength and this wavelength should remain constant. This 
wavelength is dependent on the density of the fluid mixture 30. 
Unfortunately, there can be occasional changes in the density of the fluid 
mixture 30 and these changes will cause corresponding changes in the 
wavelength of the sonic waves. These changes can be neutralized, however, 
if the frequency produced by the generator 60 is changed in a 
corresponding manner. If, for example, the density increases and nothing 
else is done, the wavelength of the sonic waves will increase. If, 
however, the frequency produced by generator 60 is increased by a 
corresponding amount, this will reduce the wavelength in an offsetting 
manner. If perfectly matched, this will cause the wavelength to remain 
constant. 
The velocity sensed by sensor 26 is proportional to the density of the 
fluid mixture 30. Thus, this velocity signal can be used to control the 
frequency of generator 60 so as to hold the wavelength of the sonic waves 
in the fluid mixture substantially constant. And this is what is done by 
the circuit embodiment shown in FIG. 5. 
As indicated in FIG. 5, an adjustable pulser circuit 62 is connected by way 
of a switch 63 to a control terminal of the amplifier 61. When switch 61 
is open, pulser 62 has no effect on the operation of transducers 18. In 
this case, the sonic waves from transducers 18 are produced in a 
continuous manner. In some cases, however, it will be desirable to have 
the transducers emit the sonic waves in a pulsed manner. This is 
accomplished by repetitively turning the sonic waves on and off. In the 
FIG. 5 embodiment, this is accomplished by closing the switch 63. Pulser 
62 produces a rectangular "on-off" type of output signal. When switch 63 
is closed, this "on-off" type signal is supplied to a control terminal of 
amplifier 61. When the pulser signal is "on", it disables the amplifier 61 
so that electrical wave signals produced by generator 60 are not passed on 
to the transducers 18. Conversely, when the signal from pulser 62 is 
"off", the amplifier 61 operates in its normal manner to pass the 
electrical waves from generator 60 on to the transducers 18 to energize 
such transducers to cause them to emit the desired sonic waves. 
The purpose of periodically turning off the sonic waves is to give the 
fluid mixture 30 a chance to relax for a spell. For some types of fluid 
mixtures, this increases the amount of material separated. The "on" time 
for transducers 18 (the length of time sonic waves are emitted into the 
fluid mixture 30) should be on the order of two (2) seconds to ten (10) 
seconds, the exact value depending on the density of the fluid mixture 
being processed. A typical value for this "on" time is five (5) seconds. 
For a frequency of 20,000 Hertz, 100,000 sound wave cycles will be 
produced for such a five second interval. The duty cycle for the pulsed 
sonic waves (the ratio of the "on" time to the sum of "on" plus "off" 
time) will normally be in the range of 80% to 20%, the selected value 
depending on the density of the fluid mixture being processed. These "on" 
time and duty cycle parameters are established by adjustment of the 
appropriate controls in the adjustable pulser 62. 
As indicated in FIG. 5, the electrical circuits for operating the second 
set of transducers 21 may be of the same construction as those used for 
operating the first set of transducers 18. Thus, a variable frequency 
generator 65 generates an electrical wave signal which is supplied by way 
of an amplifier 66 to the input of the transducer mechanism 21. An 
adjustable pulser 67 can be connected by way of a switch 68 to a control 
terminal in the amplifier 66. The initial frequencies, amplifier gains, 
"on" times and duty cycles for the two transducer mechanisms 18 and 21 may 
be, but need not be, the same. Typically, the initial frequencies for the 
transducer mechanisms 18 and 21 will be set about ten to twenty Hertz 
apart from one another. 
Operation Of The Illustrated Embodiment 
Considering now the operation of the sonic separator apparatus 10, the 
fluid mixture to be processed is supplied in a continuous manner to the 
channel structure 11 by the fluid supply pipe 27 and the inlet header box 
24. This fluid mixture, designated by reference numeral 30, flows from 
left to right through the channel structure 11 and exits by way of the 
outlet header box 28 and its discharge pipe 29. As it moves through the 
channel structure 11, the fluid mixture 30 is subjected to two distinct 
sonic wave fields. One of these wave fields is a cavitation wave field 
comprised of sonic cavitation waves produced in the fluid mixture 30 by 
the leftmost transducer mechanism 18. 
These cavitation waves travel upward in a vertical direction through the 
fluid mixture 30 from the channel structure material which is in contact 
with the core pieces 19 of the transducer mechanism 18. This direction of 
travel for the cavitation waves is perpendicular to the direction of flow 
of the fluid mixture 30. These cavitation waves travel upward until they 
meet the interface formed by the upper surface of the fluid mixture 30 and 
the air above it. For maximum production of cavitation waves, the vertical 
distance from the inner surface of the channel structure material which is 
in contact with the core pieces 19 to the interface between the fluid 
mixture and the air above it should be equal to one-third the wavelength 
of the cavitation waves. 
As the fluid mixture 30 continues its journey through the channel structure 
11, it soon encounters the second of the two sonic wave fields. This 
second wave field is a standing wave field comprised of sonic standing 
waves produced in the fluid mixture 30 by the second transducer mechanism 
21 in cooperation with a downstream sonic wave reflector formed by the 
nearer side of the weir member 50. These standing waves travel in a 
horizontal direction through the fluid mixture 30 in a back-and-forth 
manner between the channel structure material which is in contact with the 
core pieces 22 of the transducer mechanism 21 and the nearer side of the 
weir member 50. This direction of travel for the standing waves is 
parallel to the direction of flow of the fluid mixture 30. As such, it is 
perpendicular to the direction of travel of the cavitation waves produced 
by transducer mechanism 18. In order to produce standing waves, the 
horizontal distance between the inner surface of the channel structure 
material which is in contact with the core pieces 22 and the nearer side 
of the weir member 50 should be equal to a multiple of one-half of the 
wavelength of the standing wave. 
As the fluid mixture 30 passes though the cavitation wave field, the fluid 
goes through an oxidation and reduction process and becomes uniform or 
homogeneous in nature, somewhat similar to a uniform suspension. Once this 
homogeneous or uniformly suspended fluid flows beyond the influence of the 
cavitation wave field, it is exposed to the standing wave field between 
the riser portion 17 and the weir member 50. When irradiated by a standing 
wave field, agglomeration occurs at the nodes or antinodes of the standing 
wave. If the particles are denser than the fluid, they will sink after 
irradiation ceases. With an emulsion, a layer of the lighter liquid will 
form on the surface. In emulsions, the radiation pressure or steady 
component of the wave will often drive the coagulated particles to the 
surface. 
The foregoing process is irreversible. The components of the treated fluid 
mixture do not recombine. Thus, as indicated in FIG. 3, the treated 
mixture leaving the channel structure 11 may be discharged into a settling 
tank 70 and the heavier components will settle to the bottom and the 
lighter components will rise to the top. 
In the foregoing example, the first transducer mechanism 18 produced 
cavitation waves and the second transducer mechanism 21 produced standing 
waves. It should be noted, however, that this need not always be the case. 
For some types of mixtures, both of transducer mechanisms 18 and 21 may be 
operated to produce standing waves. For other types of mixtures, both of 
transducer mechanisms 18 and 21 may be operated to produce cavitation 
waves. 
Considering now the positioning of the weir members 32 and 50, it is noted 
that such positioning will be dependent on the type of fluid mixture being 
processed and on its rate of flow through the channel structure 11. At the 
beginning of a processing run, the flow of the fluid mixture should be 
started and the fluid levels in the channel structure should be checked. 
The vertical position of the leftmost weir member 32 should be adjusted to 
provide a fluid level above the transducer mechanism 18 which corresponds 
as near as possible to the desired one-third wavelength value if 
cavitation waves are to be produced. The horizontal position of the 
rightmost weir member 50 should be adjusted to provide the desired half 
wavelength multiple for the riser 17 to weir 50 spacing. The vertical 
position of the weir member 50 should be set to provide sufficient fluid 
depth to cover the active area for the transducer mechanism 21. 
The following listing is a partial list of possible applications for the 
sonic separator apparatus 10: 
(a) Separating a contaminant from oil; 
(b) Separating water from oil; 
(c) Separating a contaminant from water; 
(d) Separating impurities from coal; and 
(e) Separating contaminants from sand. 
For application (d), the fluid mixture is a slurry of impure coal particles 
mixed with an appropriate liquid. For application (e), the fluid mixture 
is a slurry of contaminated sand mixed with an appropriate liquid. 
While there have been described what are at present considered to be 
preferred embodiments of this invention, it will be obvious to those 
skilled in the art that various changes and modifications may be made 
therein without departing from the invention and it is, therefore, 
intended to cover all such changes and modifications as come within the 
true spirit and scope of the invention.