Apparatus and method for removing liquid from liquid bearing material

An apparatus and method for removing liquid from liquid bearing material is provided, the apparatus comprising a pair of spaced apart electroes for being disposed on opposite sides of the material, a unit for creating an electrostatic field between the electrodes for acting through the material to remove liquid from the material, a plurality of projections for being disposed in the material between the electrodes to assist in removing liquid from the liquid bearing material, one of the electrodes having a plurality of openings passing therethrough for respectively receciving the projections therethrough so that the projections can project into the material between the electrodes, a unit operatively interconnected to the projections to move the projections through the opening means of that one electrode to different positions thereof relative to the material between the electrodes and relative to the one electrode, and a unit for causing at least one of the projections to create an electrostatic field with another of the projections so that that electrostatic field extends between those two projections and through the material to act thereon.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a new apparatus for removing liquid from liquid 
bearing material and to a new method for removing liquid from liquid 
bearing material. 
2. Prior Art Statement 
It is known to provide an apparatus for removing liquid from liquid bearing 
material and comprising a pair of spaced electrodes for being disposed on 
opposite sides of the material, means for creating an electrostatic field 
between the electrodes for acting through the material to remove liquid 
from the material, and a plurality of needle-like projections for being 
disposed in the material between the electrodes to assist in removing 
liquid from the liquid bearing material. For example, see the U.S. Pat. 
No. to Candor, 4,236,317. 
It is also known to have the projections of such an arrangement project 
through a plurality of opening means passing through one of the 
electrodes. For example see the U.S. Pat. No. 4,341,617 to King. 
While the aforementioned U.S. Pat. No. 4,236,317, to Candor, also describes 
that the needle-like projections and the electrodes can be sonically or 
ultrasonically vibrated while the needle-like projections are projecting 
into and/or through the liquid bearing material that is disposed between 
the electrodes for further enhancing the electrostatic action in removing 
liquid from the liquid bearing material, also see the U.S. Pat. No. 
3,931,682; to Candor, the U.S. Pat. No. 4,561,953, to Muralidhara et al, 
and Chapter 14, pages 335-374 of the book Advances in Solid-Liquid 
Separation edited by H. S. Muralidhara for other examples of apparatus 
that utilize sonic or ultrasonic vibrations in combination with an 
electrostatic field to remove liquid from liquid bearing material. 
It is also known that liquid in capillaries or porous material tends to 
physically move in the direction of increasing field inhomogeneity to the 
capillary or pore mouth when an inhomogeneous electrostatic or electric 
field or non-uniform electrostatic or electric field is directed across 
that capillary or porous body. For example, see the article "Effect of a 
Corona Discharge Field On Evaporation of Liquids From Capillaries" by 
Karpovich et al, J. Eng. Phys., 1981, 41, 1333. In addition, see the 
article "Study of Electric Field-Induced Effects on Water Vapor Adsorption 
in Porous Adsorbents" by Someshwar et al, Ind. Eng. Chem. Fundam., 1985, 
24, 215-220; the article "Effect of an Electric Field on the Kinetics of 
Water Sorption by a Capillary-Porous Material" by Panchenko et al, J. Eng. 
Phys., 1972, 22, 554 and the article "Influence of Inhomogeneous Electric 
and Magnetic Fields on Internal Mass Transfer In Capillary-Porous Bodies" 
by Panasyuk et al, J. Eng. Phys., 1978, 35, 827. 
SUMMARY OF THE INVENTION 
One feature of this invention is to provide a new apparatus and method for 
removing liquid from liquid bearing material by disposing a plurality of 
projections in the material between the electrodes in a unique manner to 
assist in removing liquid from the liquid bearing material. 
In particular, it is believed according to the teachings of this invention 
that at least one of the projections can create an electrostatic field 
with another of the projections so that that electrostatic field extends 
between those two projections and through the material to act on the same 
to enhance the dewatering action of the apparatus and method. 
For example, one embodiment of this invention provides an apparatus for 
removing liquid from liquid bearing material and comprising a pair of 
spaced apart electrodes for being disposed on opposite sides of the 
material, means for creating an electrostatic field between the electrodes 
for acting through the material to remove liquid from the material, a 
plurality of projections for being disposed in the material between the 
electrodes to assist in removing liquid from the liquid bearing material, 
one of the electrodes having a plurality of opening means passing 
therethrough respectively receiving the projections therethrough so that 
the projections can project into the material between the electrodes, 
means operatively interconnected to the projections to move the 
projections through the opening means of the one electrode to different 
positions thereof relative to the material between the electrodes and 
relative to the one electrode, and means for causing at least one of the 
projections to create an electrostatic field with another of the 
projections so that that electrostatic field extends between those two 
projections and through the material to act thereon. 
Accordingly, it is an object of this invention to provide a new apparatus 
for removing liquid from liquid bearing material and having one or more of 
the novel features of this invention as set forth above or hereinafter 
shown or described. 
Another object of this invention is to provide a new method for removing 
liquid from liquid bearing material, the method of this invention having 
one or more of the novel features of this invention as set forth above or 
hereinafter shown or described.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
While the various features of this invention are hereinafter described and 
illustrated as being particularly adapted to provide an apparatus and 
method for dewatering certain types of liquid bearing material, it is to 
be understood that the various features of this invention can be utilized 
singly or in various combinations thereof to remove liquid from other 
types of liquid bearing material or to merely reduce the liquid content of 
a liquid bearing material with the resulting dewatered product still being 
considered as being relatively liquid. 
Therefore, this invention is not to be limited to only the embodiments 
illustrated in the drawings, because the drawings are merely utilized to 
illustrate some of the wide variety of uses of this invention. 
Referring now to FIGS. 1 and 2, the method and apparatus of this invention 
is generally indicated by the reference numeral 20 and comprises a pair of 
spaced apart electrodes 21 and 22 disposed on opposite sides of a liquid 
bearing material 23, such as a slurry of a liquid and particles, fibers, 
etc., the electrodes 21 and 22 being formed of any suitable electrically 
conductive material and respectively having facing sides 24 and 25 for 
being disposed in engagement with the material 23 in any of the manners 
set forth in the aforementioned four U.S. patents and Chapter 14 of the 
book Advances in Solid-Liquid Separation whereby the U.S. Pat. No. 
4,236,317; to Candorn, the U.S. Pat. No. 3,931,682, to Candor; the U.S. 
Patent to Muralidhara et al, U.S. Pat. No. 4,561,953; the U.S. Pat. No. 
4,341,617 to King, and Chapter 14 of the book Advances in Solid-Liquid 
Separation edited by H. S. Muralidhara are being incorporated into this 
disclosure by this reference thereto not only for the teachings of the 
apparatus and methods thereof but also for the teachings of some of the 
types of liquid bearing materials that can be utilized in the apparatus 
and method 20 of this invention. 
Thus, it can be seen that the electrodes 21 and 22 can comprise part of a 
stationary apparatus wherein the only movement of the electrodes 21 and 22 
is that the electrode 21 can move toward the electrode 22 as the liquid in 
the liquid bearing material 23 is being removed therefrom in a manner 
hereinafter set forth or that the electrodes 21 and 22 can comprise 
movable endless belt means for continuously dewatering the material 23 
disposed therebetween together with the belt means 21 being movable toward 
the belt means 22 as the liquid in the liquid bearing material 23 is being 
removed threfrom as will be apparent hereinafter. 
In any event, the lower electrode 22 has a plurality of passages 26 passing 
completely therethrough and normally being of a size that will permit 
liquid of the liquid bearing material 23 to pass therethrough without any 
substantial amount of the solid particles of the material 23 passing 
through the passages 26 in a manner well known in the art of dewatering 
material, such as suspensions, slurries or sludges of particles and 
liquid, etc. 
The apparatus 20 comprises means 27 for creating an electrostatic field or 
electric field 28 between the electrodes 21 and 22 for acting through the 
material 23 to remove liquid from the material 23 by the well-known 
phenomena of electrophoresis and electro-osmosis, the electrostatic field 
28 being generally uniform and theoretically having a plurality of field 
lines 29 that are disposed in spaced parallel relation and extend at right 
angles between the facing surfaces 24 and 25 of the electrodes 21 and 22 
as illustrated in FIG. 1. 
The means 27 creates such electrostatic field 28 by at least charging one 
of the electrodes 21 and 22 with either a negative or a positive potential 
while either oppositely charging the other of the electrodes 21 and 22 or 
grounding such other electrode 21 or 22, the means 27 being adapted to 
maintain the desired amount of potential differential between the 
electrodes 21 and 22 from just a few volts to many kilovolts such as 
desired, even though there may be an electrical current flow created 
between the electrodes 21 and 22. 
However, in the embodiment illustrated in FIG. 1, the means 27 is adapted 
to charge the electrode 21 with one potential through a lead 30 that is 
disposed in electrical contact with the electrode 21 and to oppositely 
charge the electrode 22 through a lead 31 that is electrically 
interconnected to the electrode 22 as illustrated. 
It is generally well known that if the electrode 21 is positively charged 
and the electrode 22 is negatively charged with the particles of thc 
liquid bearing material 23 being negatively charged, the resulting 
electrostatic field 28 causes the particles of the liquid bearing material 
23 to migrate toward the electrode 21 by the phenomena of electrophoresis 
and the liquid of the liquid bearing material 23 to be forced through the 
passages 26 of the lower electrode 22 by the phenomena of electro-osmosis. 
In order to assist in the removal of the liquid from the liquid bearing 
material 23 as the electrostatic field 28 is being applied through the 
material 23 by the electrodes 21 and 22, a pressure differential is 
created across the electrode 22 by a suction device 32 having its inlet 33 
disposed in fluid communication with a chamber defining means 34 that is 
disposed in substantial sealing relation with the lower surface 35 of the 
electrode 22 and defines a chamber 36 therewith which is in fluid 
communication with the inlet 33 of the suction device 32 so that the 
suction device 32 tends to draw the liquid through the passages 26 in the 
lower electrode 22 in a manner well known for an evacuating apparatus, the 
suction device 32 having an outlet 37 for dispensing the removed liquid 
from the suction device 32 in a manner well known in the art. 
The apparatus 20 of this invention includes a plurality of needle-like 
projections 38 formed of any suitable conductive material and being 
adapted to project into the material 23 between the electrodes 21 and 22, 
such as illustrated in FIG. 2, to assist in the dewatering or in the 
liquid removal of the liquid of the liquid bearing material 23 for the 
reasons fully set forth in the aforementioned U.S. Pat. No. 4,236,317 to 
Candor. 
If desired, the projections 38 can each have an end 39 that is secured to a 
plate 40 so that as the plate 40 moves upwardly or downwardly in the 
drawings, the projections 38 will move in unison therewith, the plate 40 
being illustrated in FIGS. 1 and 2 as being integral and one-piece with 
the projections 38 and thereby being formed of the same metallic material 
as the projections 38. However, it is to be understood that plate 40 could 
be formed of any other suitable material and could actually be formed of 
electrically insulating material as will be apparent hereinafter. 
The upper electrode 21 is provided with a plurality of openings 41 passing 
completely through the outer surface 42 and the inner surface 24 thereof 
and respectively receive the projections 38 therein so that the 
projections 38 can pass through the openings 41 to be received into the 
space between the electrodes 21 and 22 depending upon the position of the 
plate 40 relative to the electrode 21. 
The projections 38 are adapted to have a desired electrical potential 
imposed thereon by any suitable means and the means 27 previously 
described can be utilized for such purpose. However, a separate means can 
be utilized for charging the projections 38 and such separate means is 
generally indicated by the reference numeral 43 in the drawings and is 
adapted to charge the plate 40 and, thus, the projections 38 through a 
suitable lead 44 that is electrically interconnected to the plate 40 in 
any suitable manner. 
The projections 38 each has a diameter that substantially fills the 
diameter of its respective opening 41 of the electrode 21 and has a 
substantially flat end surface 45 that is adapted to be disposed 
substantially flush with the inside surface 24 of the electrode 21 in the 
manner illustrated in FIG. 1 so that not only does the liquid bearing 
material 23 become completely blocked from entering the openings 41 in the 
electrode 21, but also when the projections 38 are charged with a 
potential that is the same potential that the upper electrode 21 is being 
charged with by the means 27, the resulting electrostatic field 28 between 
the electrodes 21 and 22 is initially substantially uniform as illustrated 
in FIG. 1 by the uniformly spaced apart parallel field lines 29. However, 
as the projections 38 are being progressively moved into the material 23 
as the plate 40 is being progressively moved toward the electrode plate 21 
in the manner illustrated in FIG. 2 by suitable ram means or the like 40' 
shown in FIG. 1, the end surfaces 45 of the projections 38 create 
substantially nonuniform electrostatic fields or electric fields 46 with 
the lower electrode 22 in the manner illustrated in FIG. 2 while the 
electrode 21 is still tending to maintain the substantially uniform field 
28 with the lower electrode 22 whereby the fields 28 and 46 are 
respectively imposed on the material 23 for a purpose hereinafter 
described. 
If desired, the electrode 21, the electrode 22 and the projections 38 can 
be sonically or ultrasonically vibrated in any suitable manner during the 
dewatering operation of the apparatus 20 of this invention, such sonic or 
ultrasonic vibration imparting means being respectively illustrated by 
devices 47, 48 and 49 and being of any suitable type, such as being of the 
sonic and ultrasonic vibrating types set forth in the aforementioned three 
U.S. patents and book. However, it is to be understood that only the 
projections 38 need be vibrated, only the upper electrode 21 needs to be 
vibrated, only the lower electrode 22 needs to be vibrated or any desired 
combination thereof needs to be vibrated as desired. 
Therefore, it can be seen that the method and apparatus 20 of this 
invention can be formed of relatively simple parts to operate in a manner 
now to be described. 
With the projections 38 disposed in the up position illustrated in FIG. 1 
wherein the lower surfaces 45 thereof are disposed substantially flush 
with the lower surface 24 of the upper electrode 21, the moisture bearing 
material 23 is disposed between the electrodes 21 and 22 so as to be in 
electrical contact with the lower surface 24 of the upper electrode 21 and 
in electrical contact with the upper surface 25 of the lower electrode 22. 
The means 27 and 43 are operated in such a manner that the upper electrode 
21 and projections 38 are provided with a positive charge of the same 
value while the lower electrode 22 is provided with an equal and opposite 
negative charge so that a substantially uniform electrostatic field 28 is 
formed between the lower electrode 22 and the upper electrode 21 and ends 
45 of the projections 38 as illustrated in the drawings to act through the 
moisture bearing material 23 and thereby to begin the dewatering of the 
material 23 by causing the liquid to flow through the passages 26 by the 
phenomenon of electro-osmosis while the particles of the material 23 tend 
to migrate or move toward the upper electrode 21 by the phenomenon of 
electrophoresis. Of course, if the particles of the material 23 are 
already in a preset condition thereof so that the same will not move 
toward the electrode 21, such as would be the case as if the material 23 
was a closely packed sludge cake, a mat of fibrous material, etc., the 
liquid of the material 23, nevertheless, will tend to move toward the 
lower electrode 22 and pass out of the passages 26 thereof by the 
phenomenon of electro-osmosis and the suction being created by the suction 
device 32 and acting in the chamber 36 to tend to evactuate the chamber 36 
will assist such electrostatic field 28 in removing the liquid from the 
liquid bearing material 23. In addition, by sonically or ultrasonically 
vibrating the material 23 between the electrodes 21 and 22 by any one or 
all of the means 47, 48 and 49, such vibrating action coupled with the 
electrostatic field action 28 will further tend to remove liquid from the 
material 23 as fully set forth in the aforementioned three U.S. patents 
and book and, therefore, the theories for such liquid removal need not be 
further discussed. 
However, at any desired time during such dewatering operation of the 
apparatus 20 on the material 23, the plate 40 can be moved downwardly 
toward the electrode 21 so as to cause the projections 38 to begin to 
project inbto the material 23 below the surface 24 of the upper electrode 
21 whereby the ends 45 of the projections 38 begin to form the nonuniform 
electrostatic fields 46 with the lower electrode 22 and it is believed 
that the nonuniform fields 46 create a greater dewatering effect on the 
material 23 than is provided by a uniform electrostatic field. 
In particular, it is believed that because the nonuniform fields 46 have 
the field lines 50 thereof disposed more closely adjacent each other the 
closer the same are to the ends 45 of the projections 38 as illustrated in 
FIG. 2, such more intense portions of the electrostatic fields 46 more 
closely pack the particles of the liquid material 23 together than if the 
fields 46 had been uniform adjacent the surfaces 45 of the projections 38 
to thereby cause a greater dewatering from those particles being more 
closely compacted not only by the squeezing action between the particles 
of the material 23, but also by the electro-osmotic effect of the more 
intense position of the nonuniform fields 46. 
In addition, because some of the particles in the liquid bearing material 
23 may not be charged or be chargeable, the more intense portions 50 of 
the nonuniform fields 46 pack such particles together by the theory of 
dielectrophoresis. For example, see the U.S. Pat. No. 4,164,460, to Jordan 
et al, which is being incorporated into this disclosure by this reference 
thereto. 
Thus, it is believed that as the projections 38 have their ends 45 thereof 
moved downwardly and further away from the lower surface 24 of the upper 
electrode 21, such nonuniform fields 46 act on the material 23 in the 
above manner with the fields 46 becoming more nonuniform as the ends 45 of 
the projections 38 approach the upper surface 25 of the lower electrode 
22. In fact, the length of the projections 38 could be such that the 
projections 38 will actually eventually engage against the surface 25 of 
the lower electrode 22 except that under such conditions there would be a 
direct shorting between the projections 38 and the lower electrode 22 
whereby it may be desired to stop the movement of the projections 38 into 
the material 23 before the ends 45 of the projections 38 cause arcing or 
shorting to the lower electrode 22. 
Therefore, it can be seen that initially the apparatus 20 provides a 
uniform electrostatic or electric field 28 between the electrodes 21 and 
22 and then subsequently provides a combination of uniform field 28 and 
nonuniform electrostatic or electric fields 46 in a manner believed to 
more greatly dewater the material 23 either at a faster rate and/or with a 
greater amount of liquid removal than if the projections 38 were not being 
utilized and only the uniform field 28 was being provided between the 
electrodes 21 and 22 regardless of whether or not the vibration and 
suction means are being utilized in combination therewith or not. 
After the material 23 has been dewatered a desired amount by the apparatus 
20, the material 23 can be readily removed therefrom by merely raising the 
plate 40 relative to the electrode 21 to remove the projections 38 from 
the space between the electrodes 21 and 22, such raising of the plate 40 
causing the upper electrode 21 to strip any material that would tend to 
stick to the projections 38 off of the projections 38 as the same are 
removed to the position illustrated in FIG. 1 so that the material 23 can 
be removed from the apparatus 20 in any suitable manner, such as by 
removing the electrode 21 and plate 40 if the apparatus 20 is a batch 
apparatus or by having the material 23 removed out from between the 
electrodes 21 and 22 at the end of the belt travel thereof as in the case 
of the aforementioned U.S. Pat. No. 4,236,317 to Candor. 
Of course, the projections 38 can be utilized for dewatering by also moving 
the electrodes 38 back upwardly from their down positions to the up 
position of FIG. 1 or could be moved many times upwardly and downwardly 
within the material 23 to cause a dewatering of the material 23. In fact, 
the projections 38 can begin the dewatering operation thereof when the 
same are fully disposed downwardly in the material 23 so that the 
dewatering action takes place as the projections 38 are merely being moved 
upwardly from their fully down position to their fully up position. 
Likewise, the projections 38 can begin the dewatering process in any 
position thereof whether the same are projected into the material a 
certain amount, the full amount or not into the material 23 at all as the 
case may be and then the projections 38 may be operated in any manner and 
degree of projection and rates of movement thereof during the dewatering 
process in order to provide for an optimum dewatering action therewith. 
In addition, it may be found that it is desirable to change the value of 
the potential differential between the projections 38 and the lower 
electrode 22 during the various positions of the projections 38 relative 
to the electrode 22 so as to vary the intensity of the nonuniform fields 
46 during the dewatering operation. 
Also, it is to be understood that the ends 45 of the projections 38 can be 
shaped in any suitable manner so as to enhance not only the projecting 
action thereof into the material 23, but also to enhance the shape of the 
nonuniform fields 46 being created thereby. 
For example, another method and apparatus of this invention is generally 
indicated by the reference numeral 20A in FIGS. 3-5 and parts thereof 
similar to the parts of the method and apparatus 20 previously described 
are indicated by like reference numerals followed by the reference "A". 
In regards to the method and apparatus 20A illustrated in FIGS. 3-5 and the 
other embodiments of this invention as illustrated in FIGS. 6-15, it is to 
be understood that such methods and apparatus can have the suction means 
32 and chamber defining means 34 utilized therewith as well as the 
charging means 27 and 43 previously described as the same are merely not 
illustrated in FIGS. 3-15 (as well as in FIG. 2) in order to simplify the 
drawings and not for the purpose of indicating that such means are not 
being utilized therewith. In fact, the embodiments illustrated in FIGS. 
8-15 merely illustrate one projection and it is to be understood that a 
plurality of like projections would be utilized therewith. Also, the 
embodiments illustrated in FIGS. 8-15 do not provide the vibrating means 
47, 48 and 49 as provided in FIGS. 1-5 and it is to be understood that 
such vibration means would be utilized with the embodiments illustrated in 
FIGS. 8-15 if desired. 
As illustrated in FIGS. 3-5, it can be seen that the apparatus and method 
20A is substantially the same as the method and apparatus 20 previously 
described except that the projection means 38A respectively have 
substantially pointed end surface means 51 that are substantially conical 
and have sharp pointed apexes 52 whereby such pointed end surfaces 51 
create the nonuniform electrostatic fields 46A previously described with 
the lower electrode means 22A but with the more intense portions 50A of 
the fields 46A being morc intense than the intense portions 50 of the 
nonuniform fields 46 previously described because of the pointed 
arrangement 51, 52 of the projection means 38A. Thus, it is believed that 
a greater amount of dewatering will be created by the more intense 
portions 50A of the nonuniform fields 46A than by the intensive portions 
50 of the nonuniform fields 46 previously described. 
Therefore, since the operation of the method and apparatus 20A is 
substantially the same as the operation of the method and apparatus 20 
previously described, a further description of the operation of the method 
and apparatus 20A is not necessary. 
While the methods and apparatus 20 and 20A previously described each has 
the means 32 for creating a pressure differential across the lower 
electrode 22 or 22A, it is to be understood that a pressure differential 
could be created also across the upper electrode 21 or 21A together with 
or without the means 32 for creating a pressure differential across the 
lower electrode 22 or 22A. 
For example, reference is now made to FIG. 5 wherein it can be seen that 
the projections 38A of the apparatus 20A have been moved upwardly so as to 
provide means for directing air or any desired fluid under pressure as 
indicated by the arrows 53, into the openings 41A in the upper electrode 
21A so as to create a pressure differential across the upper electrode 21A 
and thereby act on the liquid bearing material 23A to tend to force liquid 
from the material 23A out through the lower electrode 22A as previously 
set forth, such upper electrode pressure differential creating means and 
lower electrode pressure differential creating means also being provided 
in the aforementioned U.S. Pat. No. 3,931,682 to Candor. 
While the needle-like projections 38 and 38A have been illustrated and 
described as being, in effect, in electrical contact with their respective 
upper electrodes 21 and 21A whereby separate means for charging the 
projections 38 and 38A need not be provided because merely charging the 
electrode plates 21 and 21A will cause the projections 38 and 38A to be 
charged therefrom without requiring the extra charging means 43 previously 
described, it is to be understood that the needle-like projections of this 
invention can be insulated from the upper electrode that receives the same 
respectively through opening means of such upper electrode so that the 
projections can be charged with a different potential than the potential 
being imposed upon thc electrode carrying such projections. 
For example, reference is now made to FIGS. 6 and 7 wherein another 
apparatus and method of this invention is generally indicated by the 
reference numeral 20B and parts thereof similar to the parts of the method 
and apparatus 20 and 20A previously described are indicated by like 
reference numerals followed by the reference letter "B". 
As illustrated in FIGS. 6 and 7, the apparatus and method 20B is 
substantially the same as the method and apparatus 20 previously described 
except that the upper electrode 21B carries electrically isulating means 
54 that not only lines the opening means 41B thereof so as to prevent the 
projections 38B from making elcctrical contact with the upper electrode 
21B, but also the insulating means 54 covers the upper surface 42B of the 
electrode 21B so that should the plate 40B for the needle-like projections 
38B be charged with a charge different than the potential charge of the 
upper electrode 21B, a resulting field therebetween will be muted and 
thereby not adversely affect the operation of the apparatus 20B as 
hereinafter set forth. 
The initial operation of the apparatus and method 20B of FIGS. 6 and 7 is 
substantially the same as the method and apparatus 20 of FIGS. 1 and 2 
wherein the upper electrode 21B and plate 40B are charged with the same 
potential, such as positive, while the lower electrode 22B is charged with 
the opposite potential, such as negative, to create the uniform field 28B 
therebetween for acting on the material 23B disposed between the 
electrodes 21B and 22B. 
Thereafter, the upper plate 40B is moved toward the upper electrode 21B so 
as to cause the projections 38B to now have the ends 45B thereof received 
within the material 23B and at a certain point in the depth of projection 
of the projections 38B into the material 23B, the potential to the upper 
electrode 21B can be changed to ground or to a negative potential that is 
opposite to the potential of the projections 38B such as by being charged 
with the same potential as the lower electrode 22B so that the projections 
38B not only form the nonuniform fields 46B with the lower electrode 22B 
for the purpose previously described but also the projections 38B create 
upper nonuniform fields 55 with the upper electrode 21B to operate on the 
material 21B between the upper electrode 21B and the ends 45B of the 
projections 38B in such a manner that the more intense portions 56 of the 
upper nonuniform fields 55 tend to move the particles of the liquid 
bearing material 23B with a greater intensity toward the lower ends 45B of 
the projections 38B than if the fields had merely been uniform. 
If desired, during the operation of the apparatus and method 20B, the 
charging of the upper electrode 21B can be changed from being charged with 
the same potential as the projections 38B back to being grounded or being 
charged with an opposite potential to the projections 38B and then again 
back to the same potential as the projections 38B during the time the 
projections 38B are being utilized intermediate the electrodes 21B and 22B 
to dewater the material 23B therebetween. 
Other means of this invention for electrically insulating the projections 
from the electrode through which the projections are being moved is to 
insulate the projections themselves from the electrode receiving the same. 
For example, reference is now being made to FIGS. 8 and 9 wherein another 
apparatus and method of this invention is generally indicated by the 
reference numeral 20C and parts thereof similar to the parts of the 
methods and apparatus 20-20B previously described are indicated by like 
reference numerals followed by the reference letter "C". 
As illustrated in FIGS. 8 and 9, it can be seen that the projections 38C 
are each formed in a manner similar to a nail wherein the same has an 
enlarged disk-like head or end 57 and a substantially smaller diameter 
shaft-like portion or body 58 that is interconnected to the plate 40C, 
each head 57 having a diameter that is substantially the same as the 
diameter of its respective opening 41C that is formed through the upper 
electrode plate 21C as illustrated in FIG. 8. The shaft or body portion 38 
of each projection 38C is covered with electrically insulating material 59 
so that the projections 38C can readily move in their respective openings 
41C from the position illustrated in FIG. 8 to the position illustrated in 
FIG. 9 while completely blocking any fluid flow through the openings 41C 
in the same manner as the projections 38 previously described. 
In this manner, when the projections 38C are in the position illustrated in 
FIG. 8, it can be seen that the heads 57 of the projections 38C have their 
lower flat surfaces 60 disposed substantially flush with the lower flat 
surface 24C of the upper electrode 21C so that the upper electrode 21C can 
be charged with the same charge as the projections 38C to produce the 
uniform electrostatic field 28C previously described. 
However, as the projections 38C are being moved into the material 23C in 
the manner illustrated in FIG. 9, by maintaining the charge on the 
projections 38C with the same potential as the electrode 21C, the 
projections 38C will form the nonuniform fields 46 with the lower 
electrode 22C as previously described. 
However, by charging the projections 38C with the same potential as the 
lower electrode 22C and opposite to the upper electrode 21B, the enlarged 
heads 57 of the projections 38C will respectively form upper nonuniform 
fields 61 with the upper electrode 21C in such a manner that the more 
intense portions 62 of the nonuniform fields 61 will be adjacent the heads 
57 of the projections 38C and tend to move the water toward the heads 57 
with a greater intensity than the uniform field 28C as the projections 38C 
are completely insulated from the upper electrode 21C once the heads 57 
have cleared the openings 41C in the electrode 21C. 
Therefore, the charging of the projections 38C in upper electrode 21C after 
the heads 57 of the projections 38C have been moved into the material 23C 
beyond the lower surface 24C of the upper electrode 21C permits any 
combination of charging between the projections 38C and the upper 
electrode 21C as desired. 
While the various needle-like projections of this invention have been 
previously described as projecting through openings in the upper electrode 
of the various arrangements, it is to be understood that the projections 
of this invention can project through opening means in the lower electrode 
if desired. 
For example, reference is now made to FIGS. 10 and 11 wherein another 
apparatus and method of this invention is generally indicated by the 
reference numeral 20D and parts thereof similar to the parts of the 
apparatus and methods 20-20C previously described are indicated by like 
reference numerals followed by the reference letter "D". 
As illustrated in FIGS. 10 and 11, the lower electrode 22D is provided with 
a plurality of openings 41D in addition to the passages 26D thereof for 
having the projections 38D respectively received therein so that the 
projections 38D can be charged with the same charge as the lower electrode 
22D to form the nonuniform fields 46D with the upper electrode 21D so that 
the more intense portion 50D of each nonuniform field 46D is adjacent the 
end 45D of the respective projection 38D. 
In fact, it may be found that it is best to start with the projections 38D 
fully projected into the material 23D at the start of the dewatering 
operation and subsequently pull the projections 38D down to the final 
position illustrated in FIG. 11. But, of course, the projections 38D could 
start in the position of FIG. 11 if desired or in any other position as 
previously described. 
While the projections that project through the openings in the lower 
electrode of the arrangement of this invention can be insulated from such 
lower electrode in the same manner as illustrated in FIGS. 6 and 7, the 
projections are illustrated in FIGS. 12 and 13 as being insulated from the 
lower electrode in the same manner as the upper projections in FIGS. 8 and 
9. 
In particular, another method and apparatus of this invention is generally 
indicated by the reference numeral 20E in FIGS. 12 and 13 and parts 
thereof similar to the parts of the apparatus and methods 20-20D of this 
invention are indicated by like reference numerals followed by the 
reference "E". 
As illustrated in FIGS. 12 and 13, the projections 38E have the enlarged 
heads 57E and have the body portions 58E thereof covered with insulation 
59E so as to permit the electrodes 38E to be charged with a charge 
different than the charge on the lower electrode 22E, if desired. 
For example, it can be seen in FIG. 13 that when the projection 38E is 
charged with a charge different than the charge on the lower electrode 22E 
and the projection 38E has the head 57E disposed within the material 23E 
between the electrodes 21E and 22E, a lower nonuniform electrostatic field 
63 is formed between the head 57E and the lower electrode 22E with the 
nonuniform field 63 having its more intense portion 64 being disposed 
adjacent the head 57E as previously described. 
Therefore, it can be seen that when the head 57E of a projection 38E is 
closer to the upper electrode 21E as illustrated in FIG. 12, the 
projection 38E can be provided with a charge that is opposite to the 
charge of the upper electrode 21E to create the upper nonuniform field 46E 
in the same manner as the upper nonuniform field 46D previously described. 
However, as the projection 38E has its end 57E moved closer to the lower 
electrode 22E, the charge on the projection 38E can be changed to be 
opposite to the charge on the lower electrode 22E to form the lower 
nonuniform electrostatic field 63 as illustrated in FIG. 13. 
While the various apparatus and method of ths invention previously 
described has the plurality of needle-like projection means either being 
disposed through the upper electrode or through the lower electrode, it is 
to be understood that the needle-like projections of this invention can 
have one set thereof projecting through the upper electrode and another 
set thereof projecting through the lower electrode, the two sets of 
needle-like projections either being in an aligned relation or being 
staggered relative to each other in any desired pattern. 
For example, another apparatus and method of this invention is generally 
indicated by the reference numeral 20F in FIG. 14 and parts thereof 
similar to the parts of the apparatus and methods 20-20E previously 
described are indicated by like reference numerals followed by the 
reference letter "F". 
As illustrated in FIG. 14, the apparatus and method 20F has a plurality of 
needle-like electrodes 38F previously described and extending through 
cooperating opening means 41F in the upper electrode 21F. Similarly, a 
plurality of electrode means 38F extend through opening means 41F in the 
lower electrode 22F with the lower projections 38F being formed in a 
manner similar to the upper projections 38F. 
In addition, each projection 38F has insulating means 65 disposed on the 
outer end surface 60F of the enlarged head 57F thereof. 
While the projection means 38F of the apparatus and method 20F of this 
invention have the upper set and the lower set thereof disposed in axially 
aligned relation, it is to be understood that the same could be staggered 
relative to each other so that the lower set of projections 38F could 
extend all the way from the bottom electrode 22F to the upper electrode 
21F and the upper projections 38F could extend all the way from the upper 
electrode 21F to the bottom electrode 22F as desired. 
However, in the embodiment illustrated in FIG. 14 wherein the upper and 
lower projections 38F are disposed in axially aligned relation, it can be 
seen that when the projections 38F are respectively disposed within the 
liquid bearing material 23F between the electrodes 21F and 22F, the upper 
projections 38F can be charged with a potential that is opposite to the 
potential on the lower projections 38F so as to form a nonuniform field 66 
between the enlarged heads 57F of the axially aligned projections 38F as 
illustrated in FIG. 14 wherein it can be seen that each nonuniform field 
66 has the opposed intense portions 67 thereof respectively disposed 
adjacent the peripheral edges 68 of the respective enlarged head 57F that 
are not covered by insulation means, such nonuniform field 66 acting on 
the liquid bearing material 23F between the electrodes 21F and 22F to tend 
to cause the liquid to move from the upper projection 38F to the lower 
projection 38F and the particles in the liquid bearing material 23F to 
move from the lower projcction 38F to the upper projection 38F. 
In addition, the upper projection 38F can be charged with a potential 
different than the potential charge on the upper electrode 21F to form the 
upper nonuniform field 46F for the purpose previously described. Likewise, 
the lower projection 38F can be charged with a potential that is different 
than the potential on the lower electrode 22F to form the lower nonuniform 
field 63F. For example, the upper electrode 21F can have a positive charge 
thereon while the upper projection 38F has a negative charge thereon. The 
lower electrode 22F can have a negative charge thereon and the lower 
projection 38F can have a positive charge thereon. 
It is to be understood that during the operation of the apparatus and 
method 20F the upper and lower projections 38F can have the ends 65 
thereof disposed flush with the facing surfaces 24F and 25F of the 
electrodes 21F and 22F so that substantially uniform electrostatic fields 
are created between the electrodes 21F and 22F and thereafter the 
projections 38F can be moved inwardly to any desired degree into the 
material 23F and then moved outwardly relative to the material 23F as 
desired. For example, the two projections 38F illustrated can actually 
have the insulation means 65 thereof touching each other so that the 
projections 38F will move in unison with the intermediate electrostatic 
field 66 actually beginning just below the upper electrode 21F and then be 
caused to move downwardly to almost the bottom electrode 22F as desired. 
Also, it is to be understood that the spacing between the ends 65 of the 
projections 38F of the upper and lower projections 38F can be varied from 
a close spacing therebetween to a wide space therebetween so as to cause 
the various fields 46F, 66 and 63F to operate in any desired manner on the 
material 23F. 
While the method and apparatus 20F previously described has a plurality of 
upper projections 38F and a plurality of lower projections 38F, it is to 
be understood that the method and apparatus of this invention can have 
projections that always extend between both the upper and lower electrodes 
of the apparatus, if desired. 
For example, another apparatus and method of this invention is generally 
indicated by the reference numeral 20G in FIG. 15 and parts thereof 
similar to the parts of the apparatus and methods 20-20F previously 
described are indicated by like reference numerals followed by the 
reference letter "G". 
As illustrated in FIG. 15, a plurality of projections 38G are provided 
(only one such projection 38G being illustrated in FIG. 15) that 
respectively pass through aligned openings 41G in the upper electrode 21G 
and lower electrode 22G, each projection 38G comprising a body portion 58G 
and an enlarged disk-like intermediate portion 57G that has only its other 
peripheral edge 67G exposed as the remainder of the body portion 58G on 
opposite sides of the head 57G is covered by the insulating material 59G 
as previously described. 
In this manner, each projection 38G can be provided with a charge that is 
opposite to the charge on the upper electrode 21G so as to form the upper 
nonuniform field 46G therewith with such nonuniform field 46G being caused 
to move from the upper electrode 21G down toward the bottom electrode 22G 
as the intermediate portion 57G of the projection 38G is moved downwardly. 
Of course, as the projection 38G is moved downwardly, the projection 58G 
can have the charge thereon changed so as to be opposite to the charge on 
the lower electrode 22G and thereby cause a field similar to the field 63 
of FIG. 13 to now occur between the outer peripheral surface 68G of the 
enlarged head 57G and the lower electrode 22G as desired. 
Therefore, it can be seen that in all of the various embodiments of the 
apparatus and method of this invention, the projections are utilized to 
create nonuniform fields that will act on the liquid bearing material that 
is disposed between the normal or conventional electrodes so as to enhance 
the amount of dewatering and/or cake solidification as the case may be. 
It is also to be understood that during the operation of the various 
apparatus and methods of this invention, the charging of the various 
electrodes and projections can be arranged so that the same will oscillate 
between the chargings thereof so that the resulting electrostatic fields 
will oscillate and thereby cause a dielectric heating of the liquid 
bearing material to a certain degree and then the oscillation of the 
fields can be terminated and the fields then being used to perform their 
dewatering function in the manner previously described, the heating of the 
liquid bearing material facilitating the dewatering thereof because of the 
lowering of the viscosity of the liquid through the heating thereof. 
In fact, it may be found that the sonic or ultrasonic vibrating of the 
liquid bearing material through the nonuniform fields created by the 
projections of this invention will result in a dielectric heating of the 
liquid bearing material through just the action of the particles and 
liquid moving across the angled field lines created by the projections in 
much the same manner as fully set forth in the U.S. Pat. No. 4,404,754 to 
Candor, whereby this patent is also being incorporated into this 
disclosure by this reference thereto. 
It is to be understood that the projections of this invention can be 
uniformly arranged on their respective carrying plate or could be arranged 
in any desired pattern thereon. Also, the projections could have any 
desired lengths and diameters relative to each other or could be uniform 
relative to each other as desired. 
In fact, while the projections of this invention have been described as 
"needle-like," it is to be understood that such term could apply to 
projections that are similar in size and shape to sewing needles or 
smaller or could apply to large knitting needles or larger as desired. 
Also, it may be found that the vibration of the projections of this 
invention and/or the vibration of the liquid bearing material relative to 
the projections will not only enhance the dewatering operation as 
previously described, but also such vibration action may prevent the 
particles of the liquid bearing material from adhering to the projections 
and/or electrodes so as to enhance subsequent removal of the dewatered 
material from the apparatus of this invention. 
Also, while the projections of this invention have been illustrated and 
described as having a substantially circular transverse cross-sectional 
configuration, it is to be understood that the projections of this 
invention can have any desired transverse cross-sectional configuration 
and, in fact, can have a serrated, knife-like or rectangular configuration 
with the longitudinal axis of the projection extending parallel to the 
electrode carrying the same rather than transverse thereto as previously 
described. For example, see FIGS. 16-18 of the U.S. Pat. No. 3,633,282, to 
Candor et al, whereby this patent is being incorporated into this 
disclosure by this reference thereto. 
In all of the arrangements of this invention previously described, it is to 
be understood that the voltage between the upper and lower electrodes can 
be maintained substantially uniform throughout the entire dewatering 
operation or may vary throughout the entire dewatering operation. For 
example, the voltage between the two main electrodes can initially be any 
amount, such as 50 volts, and then as more and more liquid is removed, the 
voltage can be increased so that by the time the dewatering operation is 
ended, the voltage between the two main electrodes can be several thousand 
volts or more as desired. This is because the current flow, if any, 
between the main electrodes decreases as the liquid is being removed. 
Likewise, such uniform or varying voltage can be provided between the 
projections of this invention and their cooperating main electrode or 
electrodes. 
It may be found that when dewatering with the main pair of electrodes the 
removal of the liquid of the liquid bearing material by the uniform 
electrostatic field eventually produces a cake therefrom that prevents 
further dewatering thereof because the liquid remaining in the cake no 
longer is in electrical contact with at least one of the main electrodes. 
However, it is believed that by inserting the projections of this 
invention into such cake, further dewatering thereof will take place not 
only through the previously described nonuniform field action created 
thereby, but also by the fact that such charged electrodes will now be 
placed into electrical contact with the remaining liquid in the cake to 
provide an electrical current path therethrough which will occur between 
such projections and at least one of the electrodes that provide a 
potential differential therebetween as it may be found that it is best to 
always have some electrical current flow through the liquid bearing 
material to produce a liquid removing action therefrom. 
In contrast, it may be found that it is desirable to completely 
electrically insulate the projections of this invention from the liquid 
bearing material as well as to electrically insulate the main electrodes 
therefrom either by having the contacting surfaces of the main electrodes 
covered with electrically insulating material or having the same spaced 
from the liquid bearing material as fully illustrated and described in the 
aforementioned U.S. Pat. No. 4,236,317 to Candor. 
Therefore, it can be seen that the terms "electrostatic field" and 
"electric field" as used in this application are synonomous and are 
intended to describe a uniform or nonuniform field that is created through 
the liquid bearing material disposed between two members that have a 
potential differential imposed thereon whether those members are in 
electrical contact with the liquid bearing material or electrically 
insulated therefrom. Thus, it is believed that a higher voltage between 
such members must be utilized to removed liquid from the liquid bearing 
material when no electrical current is flowing between such members and 
through the liquid bearing material than the voltage utilized when 
electrical current is flowing between such members and through the liquid 
bearing material. However, it is realized that different liquid bearing 
materials have different conductivities and that some liquid bearing 
materials have substantially no conductivity whereby the voltage utilized 
for dewatering a particular liquid bearing material will be different than 
the voltage utilized for dewatering another type of liquid bearing 
material and that the voltage utilized will be different than the voltage 
utilized for dewatering another type of liquid bearing material and that 
the voltage utilized will be different if the members are electrically 
insulated from a particular liquid bearing material than the voltage 
utilized if the members are in electrical contact with that particular 
liquid bearing material. 
While it has been previously theorized that the various nonuniform fields 
of this invention tend to more solidly move the particles of the liquid 
bearing material closer together to enhance the dewatering operation, it 
may be found that, in lieu thereof or in addition thereto, a more 
beneficial effect of the nonuniform fields of this invention is to 
actually cause a migration of the liquid in the resulting cake toward the 
projection means of this invention as it is believed that liquid in 
capillaries or porous material tends to physically move in the direction 
of increasing field inhomogeneity to the capillary or pore mouth when an 
inhomogeneous electrostatic or electric field or nonuniform electrostatic 
or electric field is directed across that capillary or porous body. For 
example, see the article "Effect of a Corona Discharge Field On 
Evaporation of Liquids From Capillaries" by Karpovich et al, J. Eng. 
Phys., 1981, 41, 1333. In addition, see the article "Study of Electric 
Field-Induced Effects On Water Vapor Adsorption In Porous Adsorbents" by 
Someshwar et al, Ind. Eng. Chem. Fundam., 1985, 24, 215-220; the article 
"Effect Of An Electric Field On The Kinetics of Water Sorption By A 
Capillary-Porous Material" by Panchenko et al, J. Eng. Phys., 1972, 22, 
554, and the article "Influence of Inhomogeneous Electric and Magnetic 
Fields on Internal Mass Transfer In Capillary-Porous Bodies" by Panasyuk 
et al, J. Eng. Phys., 1978, 35, 827, whereby these four articles are being 
incorporated into this disclosure by this reference thereto. 
Therefore, it may be found that when utilizing the basic upper and lower 
electrodes 21 and 22 to provide a uniform field therebetween for initially 
dewatering the slurry 23 disposed therebetween by the aforementioned 
electrophoretic and electro-osmotic operation, the resulting cake that 
forms against the underside 24 of the upper electrode 21 may be so 
dewatered that the upper electrode 21 no longer makes electrical contact 
with the remaining liquid in the material 23 disposed between the 
electrodes 21 and 22 even after the remaining material has been vibrated 
in the manner previously described. 
It is believed that by moving the projections 38, FIGS. 1 and 2, of this 
invention into the cake 23 below the surface 24 of the upper electrode 21, 
not only will the projections 38 be moved through the dewatered part of 
the cake adjacent the surface 24 of the upper electrode 21 so as to be 
placed into electrical contact with the liquid in the material 23 that is 
disposed below the surface 24 of the upper electrode 21 as previously set 
forth, but also it may be found that the nonuniform fields being created 
by the projections 38 with the lower electrode 22 as represented by the 
reference numeral 46 in FIG. 2 actually each has the field lines 50 
thereof radiating toward the respective projection 38 so that the 
radiating lines 50 actually cause a migration of the liquid in the pores 
of the material 23 toward the projections 38 for the reasons set forth in 
the previously mentioned four articles so that when the migrating liquid 
reaches the projections 38 then the same provides electrical continuity 
between the projections 38 and the lower electrode 22 to further the 
dewatering operation by the aforementioned electro-osmotic operation 
previously set forth. In order to enhance the migration of the liquid by 
the nonuniform fields 46 converging toward the projections 38, the 
vibration of the material 23 in any of the manners previously set forth 
may reduce the surface tension in the capillaries or pores of the material 
23 so as to further enhance the movement of the liquid in the pores or 
capillaries toward the projections 38 for the dewatering function of this 
invention as well as may form cracks or fissures in the cake material 23 
to enhance the migration toward the projections 38. 
Therefore, the operation of the method and apparatus of this invention 
illustrated in FIGS. 1 and 2 may occur as follows. 
After the electrodes 21 and 22 have been utilized to form the uniform field 
therebetween to initially dewater the material 23 as previously set forth, 
in combination with or without the vibratory action, and the cake forming 
against the under surface 24 of the electrode 21 has now been dewatered 
sufficiently that electrical continuity is no longer provided by the 
liquid in the material 23 between the upper and lower electrodes 21 and 
22, the projections 38 are initially moved downwardly so as to have the 
ends 45 thereof project below the surface 24 of the upper electrode 21 
whereby it is believed that the same will now be placed in electrical 
contact with the liquid in the material 23 that is still below the 
electrode 21 so as to further dewater the material 23 between those 
projections 38 and the lower electrode 22. However, even at this point of 
the initial insertion of the projections 38, eventually the liquid 
adjacent the projections 38 will have been dewatered away from the same so 
that it is desired to have the water flow to the projections 38. This may 
be accomplished by the aforementioned nonuniform fields 46 acting on the 
cake material around the projections 38 to tend to cause migration of the 
liquid in the pores or capillaries of the cake toward the projections 38 
and through the vibration of the cake material 23 the movement of the 
liquid will be enhanced toward the projections 38. However, it may be 
found that it is necessary to increase the voltage between the projections 
38 and the lower electrode 22 at this time in order to assure the 
migration of the liquid by the nonuniform fields 46 toward the projections 
38 as it is believed that the greater the voltage across the electrode 24 
to the projections 38, the greater the strength of the nonuniform fields 
46 in dewatering the material 23. Once the liquid reaches the projections 
38 so as to provide electrical continuity between the projections 38 and 
the lower electrode 22 for the aforementioned electro-osmotic operation, 
then the voltage between the projections 38 and the lower electrode 22 may 
be decreased until it is desired to again try to migrate liquid toward the 
projections 38 either in the last inserted position thereof or after the 
same have been further progressively moved into the cake material 23 
between the electrodes 21 and 22. Obviously, if vibration action is taking 
place when the projections 38 are being moved into the cake material 23, 
the vibrating action will reduce the force necessary to push the 
projections 38 into the cake 23. 
Thus, it can be seen that the projections 38 may not only cause the 
particles of the cake material 23 to become more closely packed by the 
nonuniform fields 46 as previously described, but also the nonuniform 
fields 46 may then cause the liquid within the pores and capillaries of 
the dewatered cake to migrate toward the projections 38 through the 
converging field lines 50 thereof as previously set forth. 
This nonuniform effect for moving the liquid that remains in the dewatered 
cake toward the projections of this invention is highlighted by the 
arrangement illustrated in FIGS. 6 and 7 of applicant's drawings wherein 
the upper nonuniform fields 55 being created between the upper electrode 
21B and the projections 38B by having the upper electrode 21B charged 
oppositely to the projections 38B obviously have the field lines 56 
thereof converging toward the projections 38B to provide nonuniform fields 
converging toward the projections 38B throughout the entire length thereof 
below the lower surface of the upper electrode 21B so that when the liquid 
reaches the projections 38B by the nonuniform field effect, the liquid 
will flow to the ends 45B of the projections 38B to be directed toward the 
lower electrode 21B by the lower fields 46B creating the electro-osmotic 
effect therebetween as previously set forth. And it can be seen that 
during the entire time the projections 38B are being moved downwardly into 
the material 23B, the upper nonuniform fields 55 are trying to direct 
liquid to the entire length of the respective projections 38B. 
Therefore, it can be seen that in all of the embodiments of this invention 
that because the nonuniform fields have the more intense portions thereof 
converge toward the projections that cooperate in forming those nonuniform 
fields, such nonuniform fields can be utilized for the purpose of causing 
the liquid remaining in the pores and capillaries of the material being 
dewatered by the apparatus and method of this invention to migrate toward 
those projections by the nonuniform field effect previously set forth with 
the nonuniform field effect being enhanced by the vibration of the 
material which reduces the surface tension or capillary holding effect of 
the capillaries on that liquid so that the liquid is more readily drawn 
toward the projections by the nonuniform field effect previously set 
forth. 
In fact, it may be found that it is desired to enhance the nonuniform field 
effect acting across the partially dewatered cake to cause the remaining 
moisture therein to migrate toward the projections of this invention. 
One apparatus and method of this invention for further enhancing the 
nonuniform field effect is generally indicated by the reference numeral 
20H in FIGS. 16-18 and parts of the method and apparatus 20H of this 
invention that are similar to the parts of the methods and apparatus 
previously set forth are indicated by like reference numerals followed by 
the reference letter "H". 
As indicated in FIG. 16, the method and apparatus 20H of this invention 
includes the upper electrode means 21H and lower electrode means 22H with 
the material 23H being disposed therebetween in the manner previously set 
forth to be dewatered by the electrodes 21H and 22H being oppositely 
charged by any suitable means, such as by the electrode 21H having a 
positive charge imposed thereon and the lower electrode 22H having a 
negative charge imposed thereon. 
The method and apparatus 20H of this invention includes a plurality of 
conductive cylindrical projections 38H being carried in spaced apart 
relation by a plate means 40H that is formed of electrically insulating 
material so that the projections 38H are completely electrically separated 
from each other by the plate means 40H but are electrically interconnected 
together by a lead means 70 to a charging means 71 which is adapted to 
charge the projections 38H with any desired potential, such as the 
positive potential illustrated. 
In addition, the upper plate 40H carries a plurality of flat conductive 
projections or plates 72 which have opposed flat sides 73 respectively 
facing the projections 38H in the pattern illustrated in FIG. 18 so that 
it can be seen that each projection 38H has four sides 73 of four plates 
72 facing the same, the upper electrode 21H having the opening means 41H 
formed therethrough in the same pattern and in the same configuration as 
the projections 38H and plates 72 so that the plates 72 and projections 
38H can be moved through the openings 41H in unison by the plate 40H. The 
openings 41H and the upper surface 42H of the upper electrode 21H being 
lined with suitable electrically insulating means 54H in the same manner 
as the electrode 21B previously described. 
The plates 72 are carried by the upper insulating plate 40H in such a 
manner that the same are adapted to be all electrically interconnected to 
a lead means 74 that is adapted to be charged by a suitable charging means 
75 with any suitable charge, such as the negative charge as illustrated in 
FIG. 16. 
While the plates 72 and projections 38H are so arranged on the insulating 
plate 40H so that the lower ends or surfaces 45H of the projections 38H 
are at the same level as the lower ends 76 of the plates 72, it is to be 
understood that the ends 45H of the projections 38H could be above or 
below the surfaces 76 of the plates 72, if desired. 
In addition, it can be seen that the ends 76 of the plates 72 carry 
electrically insulating extensions 77 thereon so that the extensions 77 
are adapted to abut against the upper surface 25H of the lower electrode 
22H should the plate 40H be moved downwardly relative to the lower 
electrode 22H to a position wherein the extensions 77 abut the surface 25H 
so that it can be seen that the projections 38H in such a situation will 
still have the lower surfaces 45H thereof spaced above the surfaces 25H of 
the lower electrode 22H so as to prevent direct shorting therebetween. In 
addition, the extensions 77 could be of a length that spaces the bottoms 
76 of the plates 72 from the surface 25H of the electrode 22H when the 
extensions 77 are against the surface 25H a distance that is greater than 
the distance that the sides 73 of the plates 72 are spaced from their 
cooperating projections 38H for a purpose hereinafter set forth. 
While the method and apparatus 20H illustrated in FIG. 16 is not shown to 
have the evacuating means 32 previously described, it is to be understood 
that the same can have such evacuation means 32 as illustrated in FIG. 1 
utilized therewith and that the plates 40H, 21H and 22H can be vibrated by 
the respective means 49H, 47H ahd 48H as previously described, if desired. 
The operation of the method and apparatus 20H of this invention will now be 
described. 
When the material 23H is initially introduced between the upper and lower 
electrodes 21H and 23H, the plate 40H can be in a raised condition so that 
the ends 45H of the projections 38H are substantially flush with the lower 
surface 24H of the upper electrode 21H so that only a uniform field will 
be created between the electrodes 21H and 22H during the initial 
dewatering operation on the material 23H as previously set forth. 
However, after the formation of a cake against the surface 24H so that the 
retained liquid in such cake is no longer in electrical contact with the 
electrode 21H or even if the same is in electrical contact but the 
dewatering operation is slowed down, the plate 40H is moved downwardly so 
that the projections 38H and plates 72 are moved into the material 23H to 
a desired degree. At this time, the plates 72 and projections 38H are 
oppositely charged with the projections 38H having an opposite charge to 
the lower electrode 22H. Since the plates 72 are oppositely charged 
relative to the projections 38H nonuniform fields 80 are created with the 
projections 38H, as illustrated in FIG. 18 with each field 80 having its 
more intense portion 81 of its field lines 82 converging toward the 
projections 38H and away from the facing sides 73 of the plates 72. 
In this manner, it is believed that relatively strong nonuniform 
electrostatic or electric fields can be created between the plates 72 and 
projections 38H by creating a relatively large voltage between the plates 
72 and the projections 38H while a normal low voltage is maintained 
between the projections 38H and the lower electrodes 22H so that the 
liquid remaining in the cake material 23H between the projections 38H and 
the plates 72 will be caused to migrate toward the projections 38H and run 
down the projections 38H or be moved toward the ends 45H thereof and be 
directed toward the lower electrode 22H by the aforementioned 
electro-osmotic action. Of course, if a vibratory action is also being 
imposed at this time, the migration of the liquid toward the projections 
38H as well as the dewatering operation between the projections 38H and 
the bottom electrode plate 22H will be enhanced as previously set forth. 
Thus, as the projections 38H and plates 72 are projected further downwardly 
into the material 23H, a greater surface area of the plates 72 and 
projections 38H have the nonuniform fields acting therebetween for 
dewatering purposes and, of course, the vibration of the material 23H will 
enhance the migration of that retained liquid toward the projections 38H 
for the reasons previously set forth. Accordingly, it can be seen that the 
cake material 23H adjacent the upper electrode 21H continuously has the 
nonuniform fields 80 acting thereon the entire time the projections 38H 
and 72 are being moved toward the lower electrode 22H so that it is 
believed that the drier part of the cake material 23H will be subjected to 
the nonuniform field effect for a longer period of time than the more wet 
portions thereof. 
Eventually, the plates 72 can have the insulating extensions 77 thereof 
abut against the surface 25H of the lower electrode 22H so as to prevent 
further insertion of the projections 38H into the material 23H. Since the 
length of the extensions 77 can be longer than the distance of a side 73 
of a plate 72 relative to its associated projection 38H, no field effect 
will be created between the plates 72 and the bottom electrode 22H. 
However, by using a different length for the extensions 77, this could be 
different. 
Therefore, it can be seen that the voltage between the side 73 of each 
plate 72 and its associated projection means 38H can be several thousand 
volts whereas the voltage between that projection 38H and the lower 
electrode 22H could be only 50 volts, if desired. Of course, it is to be 
understood that the voltage between the plates 72, projections 38H and the 
projections 38H and the electrode 22H can be any desired voltage or any 
desired changing voltage as desired. 
While the plates 72 have been illustrated as having flat sides 73, it is to 
be understood that the plates 72 can have the sides 73 thereof of any 
desired configuration. 
For example, reference is now made to FIG. 19 wherein it can be seen that 
the plates 72J have the sides 73J thereof defined on arcs that would 
describe a complete circle 83 about a particular projection 38J as 
illustrated. 
Therefore, this invention is not to be limited to any shape of the plates 
72 that cooperate with the projections 38H in forming the nonuniform 
fields 80 for the reasons previously set forth. 
In regard to the lower nonuniform fields 46H being formed between the 
projections 38H and the lower electrode 22H, it can be seen from FIG. 17 
that the field lines 84 radiate through the material 23H toward the 
particular projection 38H to also tend to move the retained liquid in the 
material 23H toward that projection 38H while the field lines that are 
between the end 45H of that projection 38H and the upper surface 25H of 
the lower electrode 22H are merely substantially vertical and therefore 
uniform between the ends 45H and a like circle area on the surface 25H of 
the lower electrode 22H for the electro-osmotic function previously set 
forth. 
Therefore, it can be seen that while the various projections of this 
invention take up a relatively small area or volume of the total area or 
volume between the upper and lower electrodes, the projections reach out 
through the nonuniform field effect thereof so as to tend to pull from a 
large area or volume of the retained liquid in the liquid bearing material 
toward those projections when those projections are being utilized to form 
nonuniform fields in the various manners previously set forth. 
Of course, after a dewatering operation with the apparatus and method 20H 
of FIG. 16, the plate 40H is moved upwardly so as to remove the 
projections 38H and plates 72 from between the electrodes 21H and 22H with 
the electrode 21H stripping any material sticking to the projections 38H 
and plates 72 as the projections 38H and plates 72 move up through their 
cooperating openings 41H of the electrode 21H as previously set forth. 
It is also to be understood that the operation of the method and apparatus 
20H of FIG. 16 can have the projections 38H and plates 72 start in their 
completely down position or in any other degree of projection into the 
material 23H rather than wait until after a dewatering operation by the 
electrodes 21H and 22H. Also, the plates 72 and projections 38H could be 
extended up through the bottom electrode 22H rather than through the upper 
electrode 21H or could project separately from opposite electrodes and 
directions as desired. 
Also, it is to be understood that the plates 72 of this invention as 
previously described could be complete cylinders of electrically 
conductive material that completely surrounds a projection 38H in a 
concentric manner therewith, if desired. 
Of course, it is to be understood that all of the projections 38H and 72 
can be of the same size and shape so as to merely create electrostatic 
fields therebetween whether such fields are uniform or nonuniform as 
desired as an important feature of this invention is to create a field 
between projections that enhances the dewatering effect of at least one of 
those projections with the regular electrodes of the dewatering apparatus 
and method. 
In addition, it might be found that it is best to start the dewatering 
operation of the method and apparatus 30H with the projections 38H and 
plates 72 in their completely down position relative to the lower 
electrode 22H so that the nonuniform fields 80 between the plates 72 and 
projections 38H will cause a migration of the particles of the material 
23H toward the projections 38H by electrophoresis, as well as by 
dielectrophoresis, and liquid toward the plates 72 by electro-osmosis. The 
particles when reaching the projections 38H may then be drawn upwardly 
toward the upper electrode 21H by the normal electrophoretic action caused 
by the electrodes 21H and 22H and the liquid when reaching the plates 72 
may then be drawn downwardly toward the lower electrode 22H by the normal 
electro-osmotic action caused by the electrodes 21H and 22H. Thus, after a 
sufficient cake of the particles of the liquid bearing material 23H has 
formed against the upper electrode 21H, or before, the projections 38H and 
plates 72 can be moved upwardly to a desired up position thereof and then 
be progressively moved downwardly as previously set forth to dewater the 
cake between the plates 72 and projections 38H in the manner previously 
described wherein the nonuniform fields 80 cause the remaining liquid in 
the cake to now move toward the projections 38H as capillaries or pores 
have now been formed by the particles forming the cake therebetween. 
In the operation of the method and apparatus 20H previously described, it 
may be found that when it is desired to dewater the cake that has formed 
between the projections 72 and 38H after each movement of the projections 
72 and 38H toward the lower electrode 22H takes place, the plates 72 
should be first charged with a potential that is the same potential to 
which the upper electrode 21H had been charged while charging the 
projections 38H to the same potential to which the lower electrode 22H had 
been charged to tend to cause the particles of the cake 23H to move toward 
the plates 72 by electrophoresis for the same reasons that the particles 
initially tended to move toward the upper electrode 21H and to tend to 
cause the liquid of the cake 23H between the plates 72 and projections 38H 
to move toward the projections 38H not only for the same reason that the 
liquid initially tended to move by electro-osmosis toward the lower 
electrode 22H, but also because of the aforementioned nonuniform field 
pulling or pushing effect of the fields 80. Thereafter, the potential on 
the projections 38H and plates 72 can be reversed so that plates 72 have 
the same potential as the lower electrode 22H and the projections 38H have 
the same potential as the upper electrode 21H not only to tend to cause 
the liquid that had been drawn toward the projections 38H to now migrate 
toward the lower electrode 22H by electro-osmosis, but also to tend to 
further dewater the cake 23H between the plates 72 and projections 38H by 
the nonuniform field effect thereon for the reasons previously set forth. 
Of course, the vibratory action can be imposed during the entire time or 
any desired part or parts of the time that the projections 38H and 72 are 
being used. Also the electrodes 21H and 22H can be charged during all, 
some or none of the time that the projections 72 and 38H are being used, 
as desired. 
Referring now to FIGS. 18 and 19, it can be seen that the closer the plates 
72 or 72J come to completing a square, the greater the amount of area of 
the nonuniform fields 80 will cover between such plates 72 and 72J and 
their respective projections 38H and 38J. Also, it is to be understood 
that additional projections 38H and 38J could be disposed between the 
adjacent four corners defined by the plates 72 and 72J to form nonuniform 
fields therewith (such as disposing a projection 38J where the reference 
number 83 is located in FIG. 19 or where the lower left reference number 
80 is located in FIG. 18). 
In this manner, substantially the entire area between the plates and 
projections will have a nonuniform field acting therethrough with the 
closeness of the plates and projections being governed by the strength of 
the electrode 21H in having the cooperating openings 41H being relatively 
close to each other. 
Thus, it is believed that the projections 38H will act as a pump means to 
pump the liquid away from the ends or mouths of the capillaries or pores 
in the cake material 23H that are adjacent the projections 38H and direct 
the thus removed liquid toward the lower electrode 22H by electro-osmosis 
whereby the liquid in the capillaries or pores will continue to be moved 
toward the projections 38H by the nonuniform fields 80 as previously set 
forth to be subsequently pumped away therefrom as previously set forth. 
Accordingly, it can be seen that it is believed that this invention of 
FIGS. 16-19 will use two field effects to enhance the dewatering operation 
of the upper and lower electrodes 21H and 22H, one field effect being 
between adjacent projections 38H and 72 and the other field effect being 
between the projections 38H and the lower electrode 22H. Such two field 
effects can take effect in unison or in series, be continuous or 
intermittent, etc. as desired. Also, the voltage for creating the two 
field effects can be the same or different as previously set forth as well 
as be oscillated as previously set forth. 
While the nonuniformity of the fields 80 of FIGS. 16, 18 and 19 is in a 
radial direction relative to the projections 38H and 38J, it is to be 
understood that a nonuniformity of the fields 80 could also be in a 
vertical direction in FIG. 16 if the projections 38H are each provided 
with spaced annular bands or spaced circles of points that project 
outwardly therefrom in a radial direction, such as illustrated in FIGS. 10 
and 11 of the aforementioned U.S. Pat. No. 4,341,617 to King. 
Such an arrangement of this invention is illustrated in FIG. 20 wherein 
another method and apparatus of this invention is generally indicated by 
the reference numeral 20K and parts thereof that are similar to parts of 
the method and apparatus 20-20J previously described are indicated by like 
reference numerals followed by the reference letter "K". 
As illustrated in FIG. 20 the method and apparatus 20K is substantially 
identical to the method and apparatus 20H of FIGS. 16 and 18 except that 
each projection 38K has a plurality of radially outwardly extending 
annular conductive bands 57K separated from each other by annular rings of 
insulating material 59K as in FIG. 15 so that the resulting electrostatic 
fields 80K created between each projection 38K and its cooperating plates 
72K are in the nonuniform vertical arrangement illustrated in FIG. 20 as 
well as in the nonuniform horizontal arrangement as illustrated in FIG. 
18. 
Therefore, it can be seen that this invention not only provides a new 
apparatus for removing liquid from liquid bearing material and the like, 
but also this invention provides a new method for removing liquid from 
liquid bearing material or the like. 
While the forms and methods of this invention now preferred have been 
illustrated and described as required by the Patent Statute, it is to be 
understood that other forms and method steps can be utilized and still 
fall within the scope of the appended claims wherein each claim sets forth 
what is believed to be known in each claim prior to this invention in the 
portion of each claim that is disposed before the terms "the improvement" 
and sets forth what is believed to be new in each claim according to this 
invention in the portion of each claim that is disposed after the terms 
"the improvement" whereby it is believed that each claim sets forth a 
novel, useful and unobvious invention within the purview of the Patent 
Statute.