Oil concentrator

In an apparatus for efficiently and thoroughly cleaning tramp oil and contaminants from machine coolant; a tank 12 having three compartments 32, 52 and 66 with a quietener baffle 58 located between the first compartment 32 and the main compartment 52, a torturous path between the main compartment 52 and the clean coolant storage compartment 66, and an agglomeration baffle 76 between the main and storage compartments 52, 66, respectively, is provided. Further, the flow quietener baffle 76 is arranged within the tank 12 so that material flowing from the first compartment 32 to the main compartment 52 will flow generally down the quietener baffle 58 and arrive in the main compartment 52, substantially at the level of the interface 46 between the floating light material 42 and the heavy material 44 with a minimum of disturbance to interface 46. Rapid and complete floatation of oily material containing heavy contaminants is achieved by the addition of aeration bubbles 62 within the first compartment 32.

TECHNICAL FIELD 
The present invention relates to apparatii used for removing and 
concentrating oily contaminants from a fluid, and more particularly to an 
apparatus for removing oily contaminants, and oil globular entrained fines 
from machine coolant in order to reclaim and reuse the coolant. 
BACKGROUND OF THE INVENTION 
Devices for removing oil from fluids are generally known in the art, as are 
devices for removing solid particles suspended within a fluid. Many of 
these devices include the use of torturous fluid paths to encourage the 
separation of fluids of differing specific gravities. Other devices within 
this field employ large settling tanks for the separation of solid 
material from the fluid. 
There are, however, recurring problems with the use of such tanks and 
systems for the separation of oily contaminants from machine coolant. 
These problems include the fact that a complicated structure for passing a 
fluid through a torturous path will necessarily be complicated to clean, 
and thus will more easily allow bacteria to accumulate within the oil 
concentrator. Further, the settling out of particulate matter increases 
the contaminant content within the oil concentrator thus reducing the 
cleaning efficiency of the mechanism. 
The preferred embodiment of the present invention overcomes these 
difficulties by employing a rather simple torturous path which is easy to 
clean and provides little area for bacteria to grow, with a cleaning 
action which encourages particulate matter to float to the surface and 
thus be removed with the oily contaminant. 
The fact that certain materials of differing specific gravities will 
separate themselves within a chamber is also known within the background 
of oil separators. The present invention is directed to providing a 
mechanism which encourages a thorough cleaning of machine coolant by 
efficiently removing the majority of contaminants from the coolant. This 
is accomplished by allowing the materials to separate according to the 
specific gravity of the various materials with the "light" material of 
lower specific gravity being skimmed from the surface of the "heavy" 
material of higher specific gravity. The present invention also provides 
an apparatus which will encourage the rapid separation of materials within 
a tank. 
The removal of oil contaminants from the coolant is necessary as these 
substances often harbor bacteria which degrade the machine coolant and 
cause an unpleasant odor. As the coolant is expensive to produce and 
expensive to dispose of for environmental reasons, there is a need to 
extend the useful life of the machine coolant by efficiently and 
economically removing the tramp oil, metal fines, and other contaminants 
from the coolant. 
The use of machine coolant including cutting oil and the like to cool 
cutting tools in industry is well known. The present invention is part of 
a complete machine coolant recovery system including a series of settling 
tanks for removing large particles and solid materials and an 
ultracentrifuge employed for removing smaller suspended particles and 
mechanically emulsified oil from the coolant. Following these steps, the 
fluid mixture entering the oil concentrator will, however, contain a 
quantity of tramp oil. This oil finds its way into the machine coolant 
from leaks within the machine being cooled and from environmental 
surfaces. Additionally, this tramp oil may contain fine particulate 
matter, such as minute machine shavings or cuttings known as fines. These 
fines may range in size from 25 to 30 microns for heavy metals and up to 
approximately 75 microns for aluminum or lighter metals. These fines are 
typically suspended within oil bubbles contained in the mixed fluid, and 
thus are not always removed by the ultracentrifuge. However, the oil 
concentrator is suited for use without a centrifuge. 
SUMMARY OF THE INVENTION 
The present invention includes a tank having different chambers for 
separating fluids of differing specific gravities. The material enters a 
first chamber having an angled bottom within the tank. Within this first 
chamber an initial separation of the mixture takes place. The oil, will 
separate from and float effectively on the machine coolant which has a 
specific gravity very nearly equal that of water. Aeration is provided 
through an aeration inlet near the bottom of the first chamber. Air is 
provided in the form of many minute air bubbles injected into the mixture 
at a relatively low pressure. The aeration aids in the separation of oil 
from the coolant and helps oil particles containing metal fines and other 
contaminants rise to the surface of the fluid within the first chamber. 
As the first chamber is generally full when the oil concentrator is 
activated, material floating on the surface within the first chamber 
immediately begins to flow into the main chamber through an opening. This 
opening is equipped with a flow quietener baffle which facilitates a 
smooth flow or transition of the material floating within the first 
chamber to the main portion of the tank. The quietener baffle minimizes 
any disturbance to the interface between the floating light weight 
material and the heavier machine coolant. As the floating oil progresses 
across the surface of the main body of the tank it approaches a waste oil 
outlet having its lowermost portion at or slightly above the interface 
between the light weight and heavy weight materials. The waste oil is then 
removed or "skimmed" from the tank by the waste oil outlet for storage, or 
reclamation. 
Fluid flow within the tank continues as machine coolant passes through a 
torturous path formed by two vertical baffles. The first vertical baffle 
is affixed to the top of the tank and descends to within a short distance 
of the bottom, and is attached to the interior surface of both sides of 
the tank. The second baffle is affixed to the bottom of the tank and 
ascends to within a short distance of the top of the tank. The top of the 
second baffle defines the level of fluid contained within the main portion 
of the tank. Machine coolant then will spill over the upper limit of the 
second baffle into a clean coolant storage chamber where it is immediately 
removed through a clean fluid outlet. The second baffle is equipped with 
an agglomeration baffle on its upper edge. This baffle extends toward the 
first vertical baffle in a direction approximately forty-five degrees 
below a horizontal plane. This agglomeration baffle helps in the 
agglomeration of any remaining fluid of light specific gravity which has 
survived the torturous path. This agglomeration takes place because of a 
velocity differential caused by the reduced area through which the fluid 
is forced to flow near the agglomeration baffle. 
These and other aspects and advantages which characterize the present 
invention are pointed out with particularity in the claims attached hereto 
and forming a part hereof. However, for a better understanding of the 
invention, its advantages, and objects attained by its use, reference 
should be had to the drawings which form a further part hereof, and to the 
accompanying descriptive disclosure, in which there is illustrated and 
described a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, wherein like reference numerals are used 
throughout the several views to indicate the same or similar elements of 
the invention, the oil concentrator 10 is shown comprising a fluid tight 
tank 12. The tank 12 has a bottom side 14, and generally vertical first 
and second end walls 16 and 18, respectively. The tank 12 further has a 
front and a back side wall, 22 and 24, respectively (see FIG. 1). The side 
and end walls rise to a common edge 26 which encircles the entire tank 12 
a uniform distance above the bottom side 14. 
Within the tank 12 angled baffle plate 28 defines a first chamber 32 having 
a generally angled or sloping bottom 34 (see FIG. 3). Fluid to be 
separated, containing machine coolant, tramp oil, and contaminants, enters 
first chamber 32 through an inlet port 36. Inlet port 36 is a pipe or 
other structure for transporting the oil and coolant mixture from a 
holding tank or centrifuge filter or other vessel (not shown). Inlet port 
36 is supported by an inlet support plate 82 which extends between the 
front and back side walls 22 and 24 (see FIGS. 1 and 4). The mixed 
material enters the first chamber 32 where it undergoes initial 
separation. This separation segregates oil from the mixture into an upper 
"light" layer and machine coolant into a lower "heavy" layer. This 
separation is caused by the differing specific gravities of oil and 
machine coolant. The two layers form an interface 46, representing the 
common boundary between the oil and the coolant. This initial separation 
is improved by a trumpet like flange 38 which helps spread material 
exiting the inlet port 36 to the sides of the first chamber 32. The 
mixture of coolant and contaminants passing through the flange 38 then 
contacts the sloping bottom 34 of the angled baffle plate 28. This contact 
also encourages any solids within the mixture to settle to the bottom of 
the first chamber 32. This contact changes the direction of flow of the 
liquids and encourages the tramp oil to rise to the surface. It is 
important for this contact to be gentle so that solid particles and other 
contaminants are carried to the surface to be removed from the tank with 
the tramp oil. Only particles too large to remain with the tramp oil 
should settle to the bottom and remain in first chamber 32. 
Oil particles containing metal fines or shavings are encouraged to rapidly 
rise to the surface of first chamber 32, and remain with the oil layer 
above interface 46 in main chamber 52, by the injection of minute bubbles 
62 into first chamber 32 through aeration inlet 84. Aeration is 
accomplished by injecting air into the mixture at a relatively low 
pressure. Pressures of 2 to 3 pounds per square inch are found to be 
satisfactory. The size of the aeration bubbles 62 is decreased by passing 
the air through sintered bronze filter screen 68 or a similar device. 
Ideally, the bubbles should be small in size so that they attach readily 
to small size oil globules within the mixture and rise to the surface 
gently. These bubbles should also permeate all of the first chamber 32. 
Larger bubbles would, of course, rise to the surface more rapidly and 
might disturb the formation of an oil/water interface within the first 
chamber 32. The injection of air under high pressure might contribute to 
foaming of the oil-coolant mixture, and form a scum which might interfere 
with the operation of the oil exit port 54. The injection of air into 
first chamber 32 increases the amount of contaminants which can be removed 
with the tramp oil. However, an amount of solid material, globular 
entrained fines, and other heavy matter may settle to the bottom of first 
chamber 32. These heavy contaminants may be removed through a drain plug 
(not shown) located in the first end wall 16 slightly above the junction 
of first end wall 16 and angled baffle plate 28. Alternatively, these 30 
heavy contaminants may be removed when the tank 12 is drained, as is 
explained below. 
Following the initial separation taking place within first chamber 32, the 
partially separated liquids egress or leave chamber 32 and enter or 
ingress main or third chamber 52. Main or third chamber 52 is relatively 
larger than first chamber 32 and contains the fluids as they undergo 
further separation. The chamber 52 is equipped with an oil exit or egress 
port 54 in the back side wall 24. The oil exit port 54 has its lowermost 
portion at or slightly above the interface 46, between oil 42 and machine 
coolant 44. This allows the oil exit port 54 to skim the lighter specific 
gravity liquid from tank 12. 
The level of oil exit port 54 relative to the interface 46 can be "fine 
tuned" by manual adjustment of elbow 55 attached to oil exit port 54. 
Elbow 55 is a ninety degree pipe elbow which is threadably engaged to a 
nipple or other fitting. Elbow 55 can be adjusted on the nipple to allow 
oil exit port 54 to "skim" the fluid above interface 46 (see FIG. 5). This 
allows the effective level of oil exit port 54 to be located slightly 
above the interface 46. This adjustment is helpful as the level of the 
interface 46 within the tank 12 may change slightly with the volume of oil 
and the specific gravity of the oil within the tank 12 at any given time. 
For example, if the elbow 55 is positioned horizontal to oil exit port 54, 
the effective level of oil exit port 54 is unchanged. If however elbow 55 
is twisted to lie above a horizontal plane, the effective level of oil 
exit port 54 is raised to the lowermost portion of the opening in elbow 
55. Elbow 55 illustrates an alternative embodiment of oil exit port 54. 
The partially separated liquids egressing or exiting the first chamber 32 
and entering or ingressing the main or third chamber 52 pass through an 
opening 56 formed within the angled baffle plate 28. The opening 56 is 
equipped with a flow quietener baffle 58 directly beneath the opening 56. 
The quietener baffle 58 is generally planar, and descends from the 
lowermost portion of the opening 56 in a plane approximately fifteen 
degrees below a horizontal plane in a direction generally toward the 
second end wall 18 and towards the coolant reservoir or second chamber 66. 
The lowermost portion of the quietener baffle 58 is at or slightly below 
the level of the interface 46 between the oil 42 and the machine coolant 
44 within the main chamber 52. The quietener baffle 58 facilitates a 
laminar flow of the partially separated mixture between the first chamber 
32 and the main chamber 52. This laminar flow is important as it minimizes 
the disturbance to the interface 46 from fluid passing between the first 
chamber and the main chamber. This aspect of the invention will allow a 
more rapid separation of light and heavy materials than could be 
accomplished if the interface were disturbed. A more rapid separation 
allows for the processing of larger amounts of mixture within a smaller 
size tank, and more importantly will allow any metal fines or shavings 
suspended within the tramp oil to be efficiently removed through oil exit 
port 54 before the particles have time to precipitate to the bottom of 
tank 12. 
Since the oil concentrator is essentially a closed vessel, the input of 
fluid through the inlet port 36 should equal the output of fluid through 
the oil exit port 54 when added to the amount of clean coolant removed 
from the tank. Clean fluid is removed through the clean coolant port 64 
located in the second end wall 18 near the lower portion thereof. Clean 
coolant port 64 is constructed and arranged to drain the coolant reservoir 
66 of its contents of clean coolant as rapidly as clean coolant passes 
over the second baffle 74. 
Although the oil concentrator operates at atmospheric pressure, as the top 
of tank 12 is open, the oil concentrator could function with a lid or 
cover (not shown) to keep out dirt and the like. 
The tank 12 is provided with a first vertical baffle 72 which is affixed 
between the front and back side walls 22 and 24, respectively, and depends 
from the edge 26 to within a short distance of the bottom side 14 (see 
FIG. 3). The first vertical baffle 72 cooperates with a second vertical 
baffle 74 to direct fluid exiting the main or third chamber into the 
relatively smaller second or reservoir chamber 66. The first and second 
baffles 72 and 74 form a torturous path for clean coolant egressing the 
main chamber 52 and ingressing coolant reservoir 66. In operation, it is 
anticipated that the vast majority of separation will take place within 
the first chamber 32 and the main chamber 52. Thus, practically no oily 
substances nor contaminants will pass the lowermost portion of first 
vertical baffle 72. 
However, it is found that a small amount of oily contaminant may still 
survive the torturous path formed by baffles 72 and 74. Removal of this 
contaminant will be greatly enhanced by the operation of the agglomeration 
baffle 76. The agglomeration baffle 76 extends from the upper portion of 
the second vertical baffle 74 toward the first baffle 72. Additionally, it 
is found that the function of the agglomeration baffle 76 is enhanced when 
it extends more than one-half of the distance between the first and second 
baffles 72 and 74. Further, when the agglomeration baffle is given a 
descending angle of approximately forty-five degrees below the horizontal, 
agglomeration baffle 76 will have a "syphoning" effect upon the 
particulate matter and oily substances which pass underneath first 
vertical baffle 72. 
The agglomeration baffle 76 causes oil globules and particulate matter 
suspended therein, to adhere to each other, mature and remain below baffle 
76. These mature or enlarged oil globules formed from smaller globules 
will accummulate underneath baffle 76 and rise toward the upper end 78 of 
the second vertical baffle 74 as they are trapped beneath the 
agglomeration baffle 76. These enlarged globules often contain particles 
of solid material and fines, consequently, when fluid flow is decreased or 
stopped these mature particles may settle to the bottom of tank 12 for 
later removal during cleaning (see below). 
The syphoning effect is caused by a transition zone adjacent to the end of 
the agglomeration baffle 76 nearest the first vertical baffle 72. This 
effect is caused by the constriction in the flow of fluid created as the 
coolant attempts to pass the agglomeration baffle 76. As the fluid passes 
through the constricted area it will increase its velocity so that the 
volume of coolant passing over the agglomeration baffle 76 is equal to the 
volume of coolant passing underneath the lowermost portion of first 
vertical baffle 72 minus any fluid removed by the agglomeration baffle 76. 
This increase in velocity will create the syphoning effect as oily 
globules having different specific gravities will experience acceleration 
at different rates compared to coolant fluid. Should the agglomerated 
material underneath the agglomeration baffle 76 accumulate to an unwanted 
extent, it may be removed from the tank 12 through the bleed hole 86. The 
bleed hole 86 is located in either the front or back side walls 22 and 24, 
respectively, underneath the agglomeration baffle 76 at the upper end 78 
of the second vertical baffle 74. Alternatively, the contents of the main 
chamber 52 can be drained through drain plug 84 located in bottom side 14 
near baffles 72 and 74. 
In operation, it is expected that the contents of the tank 12 should be 
drained periodically through drain plug 90. The entire interior surface of 
the tank 12, including the first chamber 32, the main chamber 52 and the 
coolant reservoir 66 should be hygenically cleaned at this time to remove 
bacteria and contaminants remaining within the oil concentrator. It is 
expected that this procedure will be necessary only every few months, or 
when the coolant within the oil concentrator becomes discolored. The oil 
concentrator should then be recharged with clean coolant prior to being 
placed back in service. 
For the oil concentrator to operate most efficiently, it is important that 
the oil exit port 54 be located relative to the second vertical baffle 74 
so that the lowermost portion of oil exit port 54 is no lower than a 
horizontal plane passing through the uppermost portion 78 of second 
vertical baffle 74. This geometry is desired because the oil/water 
interface 46 will lie in a horizontal plane at the level of the upper 
portion 78 of the second vertical baffle 74. Further, the quietener baffle 
58 should extend downwardly at least to this horizontal plane so that 
fluid passing over the flow quietener baffle 58 will remain in contact 
with the flow quietener baffle 58 at least until it contacts the interface 
46. It is also important that the upper portion of the second vertical 
baffle 74 be "level" from the front side wall 22 to the back side wall 24 
so that the second vertical baffle acts as a dam, and coolant spills over 
the length of the upper portion of second vertical baffle 74. The oil 
concentrator disclosed should work suitably when constructed to hold 
approximately 20 U.S. gallons or 80 liters of fluid. With this dimension a 
flow rate of 1 to 2 gallons of fluid per minute should be possible. 
Certainly larger or smaller concentrators could be built to handle larger 
or smaller flow rates. 
The present invention provides a structure for efficiently and thoroughly 
cleaning tramp oil and contaminants from machine coolant. This is 
accomplished by ensuring that fluid flow through the tank is accomplished 
with a minimum of disturbance to the interface between the floating light 
material and the heavier material. The rapid and thorough cleaning of the 
coolant is facilitated by the employment of a tank having three 
compartments with a quietener baffle located between the first compartment 
and the main compartment, a torturous path between the main compartment 
and the clean coolant storage compartment, and an agglomeration baffle 
between the main and storage compartments. Further, the flow quietener 
baffle is arranged within the tank so that material flowing from the first 
compartment to the main compartment will flow generally down the quietener 
baffle and arrive in the main compartment, substantially at the level of 
the interface between the floating light material and the heavy material. 
Rapid and complete floatation of oily material containing heavy 
contaminants is achieved by the addition of aeration bubbles within the 
first compartment. 
A number of characteristics and advantages of the invention have been set 
forth, together with the structure and operation of the invention. The 
novel features thereof are pointed out in the following claims. The above 
disclosure is merely illustrative, and changes may be made in detail with 
respect to shape, size, and structural arrangement within the principles 
of the invention to the full extent intended by the broad general meaning 
of the terms expressed in the claims.