APPARATUS FOR SEPARATING A LIGHT FROM A HEAVY FLUID

APPAREIL POUR SEPARER UN FLUIDE LEGER D'UN FLUIDE LOURD

English Abstract

The oil is separated from the rainwater that runs off a parking lot or off the
pavement of a filling station. An inlet tank (12) receives
the runoff water. When the water is entering that tank at a very low rate, the
surface water and/or oil in the inlet tank drains to a main
separation tank (21) where the oil floats on clean water. That clean water is
fed to an outlet conduit (l8) that feeds unpolluted water to the
city sewer or to a river. When the inlet flow increases to an intermediate
rate, a pipe of inverted L-shape (14) feeds clean water from the
inlet tank (12) to the outlet conduit (18). When the inlet fluid has a very
large flow rate, as might occur during a heavy downpour of rain,
the fluid level in the inlet tank (12) rises to a level at which there is a
direct overflow into the outlet conduit (18).

French Abstract

L'invention concerne la séparation de l'huile et de l'eau de pluie s'écoulant d'un parking ou d'une surface cimentée d'une station d'essence. Un réservoir d'entrée (12) reçoit l'eau de ruissellement. Quand l'eau de ruissellement entre dans ce réservoir avec un débit faible, l'eau ou/et l'huile de surface dans le réservoir d'entrée s'écoulent vers le réservoir de séparation principal (21) où l'huile flotte sur de l'eau propre. Cette eau propre est dirigée vers une conduite de sortie (18) qui amène l'eau non polluée vers des égouts urbains ou vers une rivière. Lorsque le débit d'entrée augmente à une valeur moyenne, une conduite ayant la forme d'un L renversé (14) amène l'eau propre du réservoir d'entrée (12) vers la conduite de sortie (18). Quand le débit d'entrée devient très important, par exemple en cas d'une pluie importante, le niveau du fluide dans le réservoir d'entrée (12) monte jusqu'à un niveau où il y a un débordement direct vers la conduite de sortie (18).

Claims

CLAIMS:

1. An apparatus for separating a relatively low density fluid from a
relatively
high density fluid in a stream of fluid that may vary from a very low rate of
flow to a very
large rate of flow, comprising:
(a) an inlet tank (12) for receiving into a body of fluid therein said
stream of fluid;
(b) a separation tank (21) for separating at least some of said
relatively low density fluid from said relatively high density fluid by
allowing said
relatively low density fluid to float on said relatively high density fluid;
(c) a first conduit (20), said first conduit receiving fluid from a surface of
said body of fluid in said inlet tank and discharging said received fluid into
said
separation tank;
(d) an outlet conduit (18) in fluid communication with said inlet tank,
said outlet conduit (18) operative to discharge fluid from said body of fluid;
(e) a bypass conduit (14) for receiving said relatively high density fluid
from below said surface of said body of fluid in said inlet tank and feeding
said relatively
high density fluid to said outlet conduit, said bypass conduit having an inlet
below said
surface of said body of fluid in said inlet tank and an outlet in said outlet
conduit; and
(f) a second conduit connected to said separation tank for feeding said
high density fluid to said outlet conduit;
(g) said apparatus providing at least three paths for fluid entering
said inlet tank (12) as follows:
(i) a first path from said inlet tank (12) via said first conduit (20)

13



to said separation tank (21) and then via said second conduit (122)
to said outlet conduit (18);

(ii) a second path from said inlet tank via said bypass conduit (14)
to said outlet conduit; and

(iii) a third path from said inlet tank (12) to said outlet conduit.

2. ~An apparatus as defined in claim 1, wherein said first conduit (20)
includes
an opening (27), said opening having a height and a width that communicates
with said
inlet tank (12) and permits fluid from said body of fluid in said inlet tank
(12) to flow into
said first conduit and to said separation tank (21), when said body of fluid
in said inlet
tank rises to a level of said opening.

3. ~An apparatus as defined in claim 2, wherein said width of said opening
(27) increases as said height of said opening increases (27).

4. ~An apparatus as defined in claim 1, wherein said outlet of said bypass
conduit (14) is at an elevation above said first conduit (20) so that said
first path passes
fluid when there has been prolonged fluid flow into said inlet tank (12) at
said very low
rate and that said second path passes fluid flow when there has been fluid
flow into said
inlet tank (12) at a rate higher than said very low rate.

5. ~An apparatus as defined in claim 1, further comprising an enclosure (28)
mounted in said outlet conduit, said enclosure having an opening (27) in
communication
with said inlet tank, and an outlet in communication with said first conduit.

6. ~An apparatus as defined in claim 5, wherein said enclosure (28) is located
in a lower portion of said outlet conduit (18), and said opening is operative
to permit fluid
from said body of fluid in said inlet tank (12) to flow into said first
conduit and to said
separation tank (21), when said body of fluid in said inlet tank rises to a
level of said

14


opening, and a upper portion of said outlet conduit (18) is operative for
passing fluid
from said body of fluid to downstream of said enclosure when said very large
rate of
flow occurs.

7. ~An apparatus as defined in claim 6, wherein said width of said opening
(27) increases as said height of said opening increases (27).

8. ~An apparatus as defined in claim 5, wherein said width of said opening
(27) increases as said height of said opening increases (27).

9. ~An apparatus as defined in claim 8, wherein said bypass conduit (14),
comprises at least one pipe (14) in said inlet tank, said at least one pipe
being generally
upright, and having a generally horizontal portion that passes through said
enclosure
(28) and having a portion thereof higher than the lowest portion of said
opening thereby
limiting the flow through said at least one pipe (14) to a condition where a
level of said
body of fluid in said inlet tank (12) is substantially above the lowest part
of said opening.

10. ~An apparatus as defined in claim 1,wherein said relatively high density
fluid is water and said relatively low density fluid is oil.

11. ~An apparatus as defined in claim 1, wherein said outlet conduit (18)
includes:
(a) an enclosure (28) located in said outlet conduit, said enclosure
comprising a roof (25), an opening (27), a separating wall (26), and an inlet
to said first
conduit, said enclosure (18) being closed on all sides except that it is open
at said
opening and at said inlet, said opening feeding fluid from said body of fluid
to said
enclosure, and said inlet feeding said separation tank (21); and
(b) said bypass conduit (14), passing through said

15~



enclosure (28) and discharging said relatively high density fluid passing
through said
bypass conduit downstream of said enclosure.

12. ~An apparatus as defined in claim 11, wherein said opening (27) of said
enclosure gets wider as its elevation increases.

13. ~A system for separating a relatively low density fluid from a relatively
high
density fluid in a stream of fluid that may vary from a very low rate of flow
to a very large
rate of flow, comprising:
(a) an inlet tank (12) that may receive said stream of fluid from an inlet
conduit (11) into a body of fluid therein, said inlet tank (12) comprising an
outlet conduit
(18) for receiving fluid from said body of fluid when said very large rate of
flow occurs;
(b) a separation tank (21), which when fed with fluid from said body of
fluid, will allow said relatively low density fluid to float on said
relatively high density
fluid, said separation tank having an inlet and an outlet;
(c) a first conduit (20) for receiving fluid from said body of
fluid and feeding said fluid to said inlet of said separation tank;
(d) a second conduit (122) for receiving said relatively high
density fluid from said outlet of said separation tank and delivering said
relatively high
density fluid to said outlet conduit;
(e) said inlet to said separation tank feeding fluid to said separation
tank and said outlet of said separation tank receiving fluid from said
separation tank;
(f) said first and second conduits (20, 122) being connected

16



to said outlet conduit wherein said second conduit (122) is connected to said
outlet
conduit (18) downstream of an adjacent location at which said first conduit
(20) is
connected to said outlet conduit; and
(g) a separating means (26) in said outlet conduit (18) between said
adjacent location for separating said first and second conduits and thereby
raising the
level of fluid from said body of fluid entering said first conduit.

14. ~A system as defined in claim 13, wherein said inlet to said separation
tank
(21) is at a higher elevation than said outlet of said separation tank.

15. ~A system as defined in claim 13, wherein said relatively high density
fluid
is water and said relatively low density fluid is oil.

16. ~A system according to claim 14 wherein said inlet conduit is located at
least partly in the line of sight of said outlet conduit.

17. ~A system according to claim 16 wherein said inlet conduit directs said
stream at said very large rate of flow into said inlet tank in a horizontal
direction.

18. ~A system for separating a relatively low density fluid from a relatively
high
density fluid in a stream of fluid that may vary from a low rate of flow to a
high rate of
flow, comprising:
(a) an inlet chamber (12) for receiving a body of fluid therein;
(b) an inlet pipe (11) that feeds said stream of fluid to said body
of fluid in said inlet chamber, said inlet pipe having an outlet mouth;
(c) a settling chamber (21) for separating said

17



relatively low density fluid from said relatively high density fluid by
allowing said
relatively low density fluid to float on said relatively high density fluid;
(d) a first passageway (20) for receiving fluid from said
body of fluid and delivering some of said fluid to said settling chamber, when
the rate of
flow of said stream of fluid to said inlet chamber (12) is said low rate of
flow;
(e) an outlet chamber (18) having an inlet mouth operative to
receive fluid directly from an upper surface of said body of fluid when the
rate of flow of
said stream of fluid to said inlet tank is said high rate of flow, said outlet
chamber also
having an outlet pipe; and
(f) a second passageway (122) for receiving from said settling
chamber at least some of said relatively high density fluid and delivering
said relatively
high density fluid to said outlet chamber (18) when the rate of flow of said
stream of fluid
to said inlet tank is one of said low rate of flow and said very high rate of
flow;
(g) wherein a portion of said settling chamber extends
at least as high as the fluid in said outlet chamber;
(h) said inlet mouth and said outlet mouth being at substantially the
same level, and said inlet pipe and the outlet mouth are so positioned to
provide a direct
flow path, along the upper surface of the fluid in said inlet chamber, from
said inlet pipe
to said outlet mouth.

19. ~A system according to claim 18, wherein said outlet mouth of said inlet
conduit (11) is at a level higher than said first passageway.

20. ~A system according to claim 18 in which said outlet mouth is at a higher
elevation than said second passageway.

18



21. ~A system according to claim 18, in which said outlet mouth discharges its
fluid in a substantially horizontal direction.

22. ~A device for separating a relatively low density fluid from a relatively
high
density fluid in a stream of fluid that may vary from a very low rate of flow
to a very high
rate of flow, comprising:
(a) an outlet conduit (18) having an inlet end and which
defines a passageway for said relatively high density fluid, said passageway
having a
lower part;
(b) an enclosure (28) mounted in said lower part of said passageway;
(c) said enclosure (28) having an opening proximate said inlet end of
said outlet conduit, a roof (25), a drain opening, and a separating wall (26);
(d) said enclosure (28) being closed on all sides, except at said
opening proximate said inlet end of said outlet conduit and at said drain
opening;
(e) means for feeding said relatively high density fluid that may contain
said relatively low density fluid to said inlet end of said outlet conduit;
(f) said enclosure (28) having a size substantially less than the size of
said passageway to thereby provide a space in said outlet conduit (18) around
said
enclosure thus permitting said stream of fluid entering said inlet end at said
very high
rate of flow to pass around said enclosure;
(g) said inlet end of said outlet conduit (18) comprising,

19



(i) means to allow said relatively high density fluid entering said
inlet end at said very low rate of flow to enter said enclosure and to
exit said enclosure via said drain opening; and

(ii) means to allow said stream of fluid entering said inlet end at
said very high rate of flow to flow around said enclosure (28) and to
enter said outlet conduit downstream of said enclosure;

(h) at least one bypass conduit (14) extending at least part way
through said enclosure and having an open end inside said outlet conduit; and

(i) said at least one bypass conduit (14) having an inlet end upstream
of said enclosure for receiving said relatively high density fluid that is
relatively free of
said relatively low density fluid when the rate of flow of said stream of
fluid through the
device exceeds said very low rate of flow.

23. ~A device as defined in claim 22, further comprising:
(a) a separation tank (21);
(b) a first conduit (20) for feeding fluid at said drain opening
to said separation tank (21); and
(c) a second conduit (122) connecting said separation tank
to said outlet conduit, downstream of and adjacent to said enclosure, for
discharging
said relatively high density fluid from said separation tank.

24. A device as defined in claim 22, wherein said enclosure (28) includes a
weir (13) at said opening.




25. ~A device as defined in claim 22, wherein said relatively high density
fluid is
rainwater and said relatively low density fluid is oil.

26. ~A system for separating a relatively low density fluid from a relatively
high
density fluid in a stream of fluid that may vary from a very low rate of flow
to a large rate
of flow, comprising:
(a) an inlet pipe (11) having an outlet mouth;
(b) an inlet chamber (12), fed by said outlet mouth, for receiving said
stream of fluid and having a body of fluid therein;
(c) an outlet chamber (18);
(d) a settling chamber (21) for separating at least
some of the relatively low density fluid from the relatively high density
fluid by allowing
said relatively low density fluid to float on said relatively high density
fluid;
(e) a first passageway (20) extending between said inlet chamber and
said settling chamber, which, when said stream of fluid has said low rate of
flow, feeds
fluid from said body of fluid in said inlet chamber to said settling chamber;
(f) a second passageway (122) for discharging from said settling
chamber to said outlet chamber (18) at least some of said relatively high
density fluid
when said stream of fluid has said very low rate of flow;~
(g) said relatively high density fluid in said settling chamber being
substantially free of said relatively low density fluid, while allowing said
relatively low
density fluid to collect in said settling chamber; said second passageway
having an
outlet;

21



(h) wherein said inlet chamber (12) and said outlet chamber are
positioned such that when said stream of fluid has said low rate of flow said
fluid enters
said outlet chamber via said first passageway, said settling chamber and said
second
passageway;
(i) that when said stream of fluid has said high rate of flow
said fluid enters said outlet chamber (18) directly from said inlet chamber
(12);
(j) a third passageway for passing said stream from said inlet chamber
to said outlet chamber;
(k) said inlet chamber and said passageways preventing fluid flow
through said third passageway into said outlet chamber (18) when said inlet
stream has
a low rate of flow and allows flow through said third passageway into the
outlet chamber
during periods of said high rate of flow, said outlet mouth feeding said high
rate of flow
to the fluid into said inlet chamber and into or near the surface of any fluid
in said inlet
chamber;
(l) said settling chamber (21) extending to a higher level than the fluid
level in said outlet chamber during said low rate of flow;
(m) said outlet mouth being at a substantially higher elevation than said
first passageway.

27. ~A system according to claim 26, wherein a baffle is located in said inlet
tank between said inlet conduit and said outlet conduit.

28. ~A system for separating a relatively low density fluid from a relatively
high
density fluid in a stream of fluid that may vary from a low rate of flow to a
high rate of
flow, comprising:

22


(a) an inlet pipe (11) operative to guide said stream of fluid containing
said high and low density fluid into an inlet chamber (12), said inlet pipe
having an outlet
mouth;
(b) a first passageway (20) coupled between said inlet chamber and a
settling chamber (21) operative to conduct fluid at or near a surface of fluid
in said inlet
chamber to flow to said settling chamber when said inlet flow rate is said low
rate of
flow;
(c) an outlet chamber (18), having an inlet mouth and also having an
outlet pipe;

(d) a return passageway (122) from said settling chamber to said outlet
chamber positioned to conduct fluid from below a surface of fluid in said
settling
chamber and from a region occupied by said high density fluid to said outlet
chamber
during said low rate of flow, and
(e) said settling chamber (21) extending to a vertical height
greater than said outlet pipe;~
(f) said outlet mouth feeding said high rate of flow into or near the
surface of the fluid in said inlet chamber.

29. ~Apparatus for separating a relatively light fluid from a relatively heavy
fluid in a
stream of fluid that may vary in its rate of flow from a very low to a very
high rate,
comprising:
(a) first means in the form of input means (11, 12; 51, 52;61,62;71,72) for
receiving said stream, said input means including an inlet conduit (11; 51;61;
71) and
also including an inlet tank (12;52;62;72) downstream of said inlet conduit
(11;etc) for

23


receiving said stream both when said stream has said very low rate of flow and
when
said stream has a rate of flow above said very low rate,
(b) said inlet conduit (11;etc) having an outlet mouth where said inlet
conduit (11; etc) feeds said stream to said inlet tank (12;etc);
(c) a main separation tank (21;511;611;711) for separating at least
some of said relatively light fluid from said relatively heavy fluid by
allowing said
relatively light fluid to float on said relatively heavy fluid;
(d) second means (20;510;610;722) which, when said stream has a
relatively very low rate of flow, feeds fluid from said inlet tank (12;etc) to
said main
separation tank (21;etc) in which at least some of said relatively fight fluid
floats on said
relatively heavy fluid;
(e) an outlet conduit (18;58;68;78), at least a portion of said main
separation tank (21;etc) extending at least as high as the level of at least a
portion of
said outlet conduit (18; etc);
(f) third means (25';57';64';74') which when said stream has a relatively
very high rate of flow allows most of said relatively heavy fluid of said
stream to flow
directly from said inlet tank (12;etc) to said outlet conduit (18;etc) without
passing
through said main separation tank (21;etc), said third means (25';57';64';74')
comprising
an inlet mouth (25';57';64';74') of said outlet conduit (18;etc) at said inlet
tank (12;etc);
and
(g) fourth means (122;512;612;70) for feeding said relatively heavy fluid in
said main separation tank (21;etc) to said outlet conduit (18;etc),
characterized in that
said inlet mouth (25';etc) of said outlet conduit (18;etc) is at substantially
the same level
as said outlet mouth of said inlet conduit (11;etc).

24



30. Apparatus for separating a relatively light fluid from a relatively heavy
fluid in a
stream of fluid that may vary in its rate of flow from a very low to a very
high rate,
comprising;
(a) first means in the form of input means (11, 12;51,52;61,62;71,72) for
receiving said stream, said input means (11,12,etc) including an inlet tank
(12;52;62;72)
for receiving at least a portion of said stream when said stream has a rate of
flow above
said very low rate;
(b) a main separation tank (21;511;6111;7111) for separating at least some of
said relatively light fluid form said relatively heavy fluid by allowing said
relatively light
fluid to float on said relatively heavy fluid;
(c) second means (20;510;610;722) which, when said stream has a relatively
very low rate of low, feeds fluid from said input means (11,12;etc) to said
main
separation tank (21;etc) in which any said relatively light fluid floats on
said relatively
heavy fluid;
(d) an outlet conduit (18;58,68;78);
(e) third means (25';57';64';74') which when said stream has a relatively very
high rate of flow allows most of said relatively very heavy fluid of said
stream to flow
directly from said inlet tank (12;etc) to said outlet conduit (18;etc) without
passing
through said main separation tank (21;etc); and
(f) fourth means (122;512;612;70) for feeding said relatively heavy fluid in
said main separation tank (21;etc) to said outlet conduit (18;etc),
(g) fifth means (14;54;64;74) associated with said inlet tank (12;etc) and
extending upwardly from a level below an upper end of said second means
(20;etc) to a
level no lower than said upper end and serving, when said stream has an
intermediate

25



rate of flow, to enable said relatively heavy fluid in said inlet tank
(12;etc) to flow to said
outlet conduit (18;etc) without contacting fluid in said separation tank
(21;etc).

31. A method of separating a relatively light fluid from a relatively heavy
fluid in a
stream of fluid, comprising;
(a) receiving at least a portion of said stream in an inlet tank (12;52;62;72)
when
said stream has a relatively very low flow rate, and/or an intermediate flow
rate and,
and/or, a relatively very high flow rate;
(b) when said stream has said relatively very low flow rate, feeding fluid
from said
inlet tank (12;etc) to a main separation tank (21;511;611;711) so that said
relatively light
fluid in said separation tank (21;etc) floats on said relatively heavy fluid
in said
separation tank (21;etc);
(c) when said stream has said relatively very high flow rate, most of said
relatively heavy fluid of said stream flowing directly from said inlet tank
(12;etc) to an
outlet conduit (18;58;68;78) without passing through said separation tank
(21;etc);
(d) feeding said relatively heavy fluid in said separation tank (21;etc) to
said
outlet conduit (18;etc); and
(e) characterized by, when said stream has said intermediate flow rate,
feeding
said relatively heavy fluid in said inlet tank (12;etc) from below a layer of
said relatively
light fluid in said inlet tank (12; etc) to said outlet conduit (18;etc)
without it contracting
fluid in said separation tank (21;etc).

32. A system for separating a relatively low density fluid from a relatively
high density
fluid in a stream of fluid that may vary from a very low rate of flow to a
very high rate of
flow, comprising:

26



a) an inlet tank (12) having a body of fluid therein;
b) an outlet conduit for passing fluid out of said system, said outlet conduit
having a first input and a second input;
c) a separation tank (21) comprising means for separating said relatively low
density fluid from said relatively high density fluid by allowing said
relatively low density
fluid to float on said relatively high density fluid, wherein at least a
portion of said
separation tank (21) extends at least as high as the level of at least a
portion of said
outlet conduit (18);
d) a first conduit (20) for receiving fluid from said body of fluid and
delivering
said fluid to said separation tank, when the rate of flow of said stream of
fluid is said
very low rate of flow;
e) a second conduit (122) for discharging from said separation tank at least
some of said relatively high density fluid to said first input, said
relatively high density
fluid being substantially free of said relatively low density fluid while
allowing said
relatively low density fluid to collect in said separation tank; and
f) an inlet conduit (11) that feeds said stream of fluid to said body of
fluid, said
inlet conduit being positioned to direct said stream of fluid along an upper
surface of
said body of fluid to said second input when the rate of flow of said stream
of fluid is
said very high rate of flow.

33. A system for separating a relatively low density fluid from a relatively
high density
fluid in a stream of fluid that may vary from a very low rate of flow to a
very high rate of
flow comprising:

27



a) an inlet tank for receiving into a body of fluid therein said stream of
fluid from
an inlet conduit;
b) a separation tank (21) for separating at least some of the relatively low
density fluid from the relatively high density fluid by allowing said
relatively low density
fluid to float on said relatively high density fluid;
c) a first conduit (20) extending between said inlet tank and said separation
tank, which feeds fluid from said body of fluid to said separation tank so
that any of said
relatively low density fluid in said separation tank may float on said
relatively high
density fluid in said separation tank;
d) a second conduit (122) for discharging from said separation tank at least
some of said relatively high density fluid, said relatively high density fluid
being
substantially free of said relatively low density fluid, while allowing said
relatively low
density fluid to collect in said separation tank;
e) an output conduit having a first input and a second input, said first input
operative to receive fluid from said second conduit (122), said second input
comprising
a weir over which fluid passes from said inlet tank during said very high rate
of flow; and
wherein said separation tank (21) extends to a vertical elevation at least as
high as the
lowest part of said outlet conduit (18),
and wherein during said very high rate of flow said inlet conduit feeds fluid
into said inlet
tank at a level near a surface of the body of fluid thus allowing the fluid to
pass directly
from said inlet conduit to said weir of said output conduit.
34. A system as defined in claim 26 in which said outlet mouth is at a
substantially
higher elevation than both of said passageways.
28


35. A system according to claim 28, wherein:
said inlet mouth and said outlet mouth being at substantially the same level,
and
said inlet mouth and said outlet mouth are so positioned so as to provide a
direct flow
path along the upper surface of the fluid in said inlet chamber from said
inlet mouth to
said outlet mouth.

36. A system according to claim 26 in which said outlet mouth is positioned to
discharge said stream into said input chamber horizontally and at
substantially the same
elevation as said flow over said wall.

37. A system according to claim 28 in which said outlet mouth is positioned to
discharge said stream into said input chamber horizontally and at
substantially the same
elevation as said inlet mouth.

38. A system according to claim 26, wherein:
said inlet mouth and said outlet mouth being at substantially the same level,
and
said inlet mouth and the outlet mouth are so positioned as to provide a direct
flow along
the upper surface of the fluid in said inlet chamber from said inlet mouth to
said outlet
mouth.

39. In a system that when fed by a stream of fluid, whose rate of flow varies
from a
low to a high rate and is composed of a first fluid and a second heavier
fluid, will
separate the first fluid from the second heavier fluid, comprising:
(a) an inlet chamber,
(b) a settling chamber,
(c) an outlet chamber,
(d) said inlet chamber having a sidewall,

29



(e) a first passageway through said sidewall, which if and when the fluid
level
in said inlet chamber rises to the elevation of said first passageway, feeds
fluid from
said inlet chamber to said settling chamber,
(f) said first passageway comprising means which will allow said low rate, but
not said high rate of flow therethrough,
(g) a second passageway for passing at least some of said second fluid from
said settling chamber to said outlet chamber,
(h) said inlet chamber and said outlet chamber having a common wall which
has an opening between those two chambers, so that if and when said stream is
fed to
said inlet chamber, the surface fluid in said inlet chamber will flow through
said first
passageway when there is said low rate of flow and will pass through both of
said first
passageway and said opening when said stream has said high rate of flow,
(i) said settling chamber extending to an elevation at least as high as said
outlet chamber, and
(j) said stream when fed to said system is fed into or near the surface of any
fluid in said inlet chamber.

40. In a system that when fed by a stream of fluid, whose rate of flow varies
from a
low to a high rate and is composed of a first fluid and a second heavier
fluid, will
separate the first fluid from the second heavier fluid, comprising:
(a) an inlet chamber,
(b) a settling chamber,

30



(c) an outlet chamber,
(d) said inlet chamber having a sidewall,
(e) a first passageway through said sidewall, which if and when the fluid
level
in said inlet chamber rises to the elevation of said first passageway, feeds
fluid from
said inlet chamber to said settling chamber,
(f) said first passageway comprising means which will allow said low rate, but
not said high rate of flow therethrough,
(g) a second passageway for passing at least some of said second fluid from
said settling chamber to said outlet chamber,
(h) said inlet chamber and said outlet chamber having a common wall which
has an opening between those two chambers, so that if and when said stream is
fed to
said inlet chamber, the surface fluid in said inlet chamber will flow through
said first
passageway when there is said low rate of flow and will pass through both of
said first
passageway and said opening when said stream has said high rate of flow,
(i) said settling chamber extending to an elevation at least as high as said
outlet chamber, and
(j) said sidewall having an inlet opening through which said stream may be
fed into said inlet chamber to or near the surface of the fluid in said inlet
chamber.

31

Description

CA 02236354 2004-03-25
APPARATUS FOR SEPARATING A
LIGHT FROM A HEAVY FLUID
TECHNICAL FIELD
This invention relates to separating a heavy fluid such
as water from a lighter fluid such as oil.
BACKGROUND OF THE INVENTION
Some local laws require the owners of filling stations,
parking lots, etc. to remove the oil from the runoff water that
drains from the premises. Oil enters said runoff water since
automobiles often leak oil. Moreover, there may be spillage from
a tanker truck. Such oil, if not removed from the runoff water,
will pollute the river or other place which receives the runoff
water.
Apparatus for removing oil from runoff water is
available but the only commercial devices for removing oil from
runoff water requires all of the parts to be shipped from the
factory. See, for example, U.S. Patent 4,985,148 granted January
15, 1991 to Monteith. It is desirable to provide a system that
can be fabricated and built by local contractors using locally
available parts to the extent possible.
It is also desirable to provide apparatus for removing
oil from runoff water that is more effective than the equipment
now available. This improved effectiveness, in the present
invention, involves improvements in systems that have two tanks.
The prior art includes a number of patents wherein two tanks are
used in processing water that is laden with oil. Such U.S.
Patents include:
Kuntzer 1,778,326
Sorg 2,820,550
Fontaine 3,258,123
Russell et al. 5,122,280
Guthy 5,196,123
Schweizer et al. 5,246,592
Greene 5,433,845
Monteith 5,498,331, and
British Patent document 2,127,319, Cochrane
None of these patents, however, solve the problem of
handling the various problems involved in removing oil from
runoff water. One of these problems involves the large

CA 02236354 2004-03-25
2
variations in the rate of flow of the water. The rate of flow
may be very low in the case of a very light rain and may be a
very high rate as would be involved during a heavy thunderstorm.
DISCLOSURE OF THE INVENTION
The runoff water enters an inlet tank where oil floats
on fairly clean water. When water enters the inlet tank at a low
rate, the surface of the liquid in the inlet tank is fed to a
main separation tank where again the oil floats and is thereby
separated from the water.
Clean (below surface) water from the main separation
tank is fed to an outlet conduit which delivers the clean water
to a city sewer, river or the like.
If the runoff stream has an intermediate rate of flow,
clean (below surface) water is fed from inlet tank directly to
the outlet conduit. This path for the water is in addition to
flow along the path described in the immediately preceding
paragraph.
When the runoff water enters the inlet tank at a very
high rate, for example during a thunderstorm, there is a third
path for the water that is in addition to the two paths
previously described. The runoff water takes this third path
when the flow rate causes the inlet tank to fill to a given high
level. The outlet conduit is fed directly by the inlet tank when
the fluid in the inlet tank reaches the aforesaid high level.
Most, if not all, of the oil on the pavement of the
filling station or parking lot is generally removed from the
pavement, and separated from the water in said main separation
tank, before the inlet tank is filled to said high level at which
the inlet tank directly feeds said outlet conduit.
The present invention is more effective than any other
system for cleaning runoff water.
In the preferred form of the invention, a small
enclosure, mounted in the outlet conduit, receives the surface
fluid of the inlet tank under normal conditions of a low intake
flow rate. The fluid in said enclosure drains to said main
separation tank. Under intermediate rates of fluid flow into the

CA 02236354 2004-03-25
3
inlet tank, a further flow path through a pipe of inverted L-
shape delivers clean water from the inlet tank directly to the
outlet conduit. During very high rates of flow of the intake
fluid, the fluid in the intake tank overflows said enclosure and
passes directly to the outlet conduit. Clean water from the main
separation tank is fed to the outlet conduit.
In one modified form of the invention, said enclosure
is omitted. During periods of a low intake flow rate, surface
fluid in the intake tank flows directly through a side wall of
that tank to the pipe that feeds the main separation tank. An
inverted L-shaped pipe feeds clean water from the inlet tank to
the outlet conduit when the intake fluid has an intermediate flow
rate. At high rates of intake flow, the fluid in the intake tank
builds up in height until it overflows into the outlet conduit.
A further improvement is achieved if a baffle is
mounted in the inlet tank in front of the opening into the outlet
conduit. This baffle prevents oil from entering the outlet
conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a vertical sectional view through the
middle of a first embodiment of my invention.
Figure 2 is a sectional view along line 2-2 of Figure
1.
1.
1.
1.
Figure 3 is a sectional view along line 3-3 of Figure
Figure 4 is a sectional view along line 4-4 of Figure
Figure 5 is a sectional view along line 5-5 of Figure
Figure 6 is a top view of the embodiment of Figure 2.
Figure 7 is a schematic view of a first modified form
of the invention.
Figure 8 is a top view of the modified form of Figure
'7.

CA 02236354 2004-03-25
4
Figure 9 is a detailed view of certain parts of the
modified form of Figure 7.
Figure 10 is a detailed view of a portion of the outlet
conduit 58 of Figure 7.
Figure 11 is a schematic view of a second modified form
of the invention.
Figure 12 is a top view of said second modified form of
Figure 11.
Figure 13 shows a modified form of the inlet pipe that
may be used with the invention.
Figure 14 is a schematic diagram of another modified
form of the invention.
Figure 15 is a cut-away view along line 15-15 of Figure
14.
MODES FOR CARRYING OUT THE INVENTION
In the preferred form of Figure 1, the inlet tank 12 or
inlet chamber 12 is a drop manhole underground and has an inlet
pipe 11 or inlet chamber 11. The inlet pipe 11 is fed by the
rainwater runoff from parking lots for example. This runoff may
include oil that was left on the parking lot by automobiles. The
runoff may vary from a small amount that has a very low rate of
flow to a very high rate of flow. The low rate of flow may be
the result of a person washing the lot with a hose or from a
light rain. The very high rate of flow may be the result of a
heavy downpour such as might occur during a thunderstorm. The
inlet tank 12 and the main separation tank 21 or settling chamber
21 are preferably of round cross-section and are drop manholes
with their upper-ends closed by manhole covers (not shown). The
rainwater runoff enters the inlet tank 12 through inlet pipe 11
and fills the tank 12 until there is overflow at weir 13.
Surface water is skimmed by weir 13.
The outlet conduit 18 or outlet chamber 18 extends from
the inlet tank 12 to a suitable place for disposing of clean

CA 02236354 2004-03-25
water. There are at least two inputs to the outlet conduit 18,
which may be referred to as the first and second inputs,
respectively.
When water overflows the weir 13, it builds up in
5 enclosure 28, passes into pipe 20 or first passageway 20 and
builds up in main separation tank 21. Any oil in the runoff
water floats on the water in inlet tank 12 and also floats on the
water in the main separation tank 21. When the fluid in tank 21
builds up to a level higher than the outlet (top) end of pipe 122
or second passageway 122 or return passageway 112 the clean water
from the lower part of the main separation tank 21 flows via pipe
122 to outlet conduit 18. Pipe 122 may be referred to as the
first input of the outlet conduit 18.
When the rate of flow of the runoff water passing
through inlet 11 increases to an intermediate rate of flow,
substantially clean water from inlet tank 12 passes upward
through the vertical portions of the two pipes 14, then enters
the horizontal portions of those pipes and discharges into outlet
conduit 18 directly. Such discharge takes place downstream of
the enclosure 28 since the horizontal portions of pipes 14 pass
completely through the enclosure 28.
At a still higher rate of intake flow the so-called
second input of the outlet conduit 18 is active as the level of
the liquid in tank 12 increases until there is a direct flow path
along the upper surface of the body of fluid in inlet tank 12
from inlet 11 to the outlet conduit 18. This flow path is
through the space above the roof 25 of enclosure 28 and extends
from the inlet tank 12 to that part of the outlet conduit 18
which is downstream of the enclosure 28. In that situation the
enclosure 28 and roof 25 (see Figs. 1-4) act as a weir, allowing
high volume flow to flow out the second input to the outlet
conduit 18 only when tank 12 is filled above the level of roof
25. A separating wall 26 separates the enclosure 28 from the
outlet conduit 18.
The operation of the system of Figure 1 during different
rates of flow of the inlet stream will now be described. If rain

CA 02236354 2004-03-25
6
falls at a very low rate, the inlet flow rate, in pipe 11, is
slow. The inlet tank may have water and oil in it from a
previous rain or it may begin to fill from the present rain. In
either case the inlet tank fills until it begins to overflow the
lowest part 24 of the U-shaped opening 22-24-22 of weir 13. The
width of the U-shaped weir increases as the height of the weir
increases. Weir 13 skims the surface fluid and allows it to
partially fill enclosure 28 then drain via pipe 20 to the main
separation tank 21. The tank 21 fills until the fluid level in
pipe 122 rises to the invert of outlet conduit 18. Since the
conditions in tank 21 are very calm the oil floats on the water
in this tank. Thus, the fluid fed from tank 21 via pipe 122 to
outlet conduit 18 is clear water.
The water level in enclosure 28 must be higher than the
outlet end of pipe 122 in order to have flow from the main
separation tank 21 to outlet conduit 18. This result is achieved
in Figure 1 by the weir 13 which holds water in enclosure 28 when
pipe 20 is full.
If now or at any later time the flow rate at the inlet
pipe 11 increases to what may be called an intermediate flow
rate, water in the two pipes 14 will pass clean (below surface)
water from inlet tank 12 directly to outlet conduit 18, as
previously explained.
If then, or later, the rate of flow in inlet pipe 11
increases to a very high rate, as during a heavy thunderstorm,
the fluid in inlet tank 12 will rise rapidly and overflow the
enclosure 28, passing above roof 25, and enter the outlet conduit
18.
It is noted that during the very high rate of flow,
just described, fluid is still passing over weir 13 into
enclosure 28 and via pipe 20 to the main separation tank 21, and
from there via pipe 122 to outlet conduit 18. Moreover, during
such very high rate of flow, water is still flowing through pipes
14 to the outlet conduit 18.
Similarly, during the intermediate rate of flow, water
is flowing not only through pipes 14, but also over weir 13,

CA 02236354 2004-03-25
7
through enclosure 28 to main separation tank 21, and via pipe 122
to the outlet 18.
While a very large flow of water through the outlet
conduit 18 may cause a small Bernoulli effect upon the water in
the main separation tank 12 and the pipe 122, the oil that is
floating on the water in the main separation tank 12 will remain
in place and substantially unaffected by the very large flow in
outlet conduit 18. Even if the outlet conduit became partially
or totally blocked, the oil that floats on the water in the main
separation tank will remain in tank 12 and separated from the
water therein irrespective of the amount of water received at
inlet 11.
Figures 7 to 10 illustrate a first modified form of the
invention. This modified form will now be described.
Water contaminated with oil enters the drop manhole 52,
also sometimes hereinafter referred to as an inlet tank, through
an orifice 51. In the drop manhole 52, the oil will float on the
water. Solids will settle to the bottom of the drop manhole 52.
As the drop manhole 52 fills with liquid, the oil (surface
liquid) will rise to the surface. The surface elevation is
controlled by a device such as the top surface 57 of pipe 54.
The device must be such that it controls the surface elevation of
the liquid such that it is higher than the ultimate outfall
height to allow for the separation process to occur. As the
liquid level rises it will first flow into a surface skimming
outlet port 55 which is connected to a pipe 510 which allows the
surface skimmed material (oil) to flow into the oil collection
manhole 511. This manhole 511 is hereafter sometimes referred to
as a main separation tank. In this manhole, the oil will float
on the surface. As additional oil flows into the oil collection
manhole 511 it will displace water because the oil will float to
the surface and the outlet of the manhole to pipe 512 is at a
below surface elevation. Keeping the invert elevation of the
outlet pipe 512 below that of the inlet pipe 510 is ideal. The
outlet pipe 512 will then carry treated water (oil removed) to an
orifice in the bottom of the clean water outlet conduit 58. This

CA 02236354 2004-03-25
will be cleaned flow with sediment settled to the bottom of both
manholes 52 and 511 and the oil removed and trapped in the oil
collection manhole 511.
During relatively high flow volumes, rainwater enters
the drop manhole 52, and flows through the skimming outlet port
55. The height of the fluid continues to rise in elevation until
it reaches the height of the elbow in the clean bypass pipe 54.
This pipe extends through dam 53. As the liquid level rises
above the invert of the elbow of the clean bypass pipe 54, clean
water will be forced through the pipe 54. Since the oil will be
at or near the surface, and the entrance point of the liquid into
the clean bypass pipe 54 is significantly below this, below
surface (clean) water will enter the lower open end of the pipe
54 and the gravity, acting on the surface, will force the water
up through the clean water bypass pipe 54 through the elbow in
the clean bypass pipe 54 and through dam 53 to the clean water
outlet 58 as "cleaned" bypass flow. Meanwhile the surface
liquids will continuously be treated by the process described in
the paragraph above.
During an extreme flow situation (such as a
thunderstorm), the system must continue to flow, and the height
of the liquid in the drop manhole 52 rises to the elevation
higher than the top 57 of the clean bypass pipe 54 and dam 53.
The top 57 of the clean bypass pipe 54 will then act as a weir
together with the elevation control dam 53 such that when the
flow is so great that separation can no longer occur, the entire
system goes into an untreated bypass mode so as not to cause any
backup in the system during this severe storm event. At this
point the surface flow will no longer be treated and will flow
over the top 57 of the dam 53 and bypass pipe 54 directly to the
clean water outlet 58. Flow will continue through the separation
system but it will no longer be surface flow so the primary
function of the system will cease. However, all previously
separated liquid will remain contained in the collection manhole
511 until it is removed by pumping.
The elevation of the dam 53 determines the elevation of

CA 02236354 2004-03-25
9
the liquid in the collection manhole 511 by the simple laws of
gravity, since they are connected and vented. As the liquid in
inlet tank 52 exceeds the elevation of the top 57 of dam 53 and
the bypass elbow pipe 54, it will flow directly and untreated
from the drop manhole 52 through to the clean water outlet 58.
The storage capacity of the collection manhole 511 can
be increased by inserting a pipe into the collection manhole 511
with an invert higher than the incoming pipe 510 but such that
the top of the calculated volume being no higher than the
elevation of the crest height of dam 53. The pipe will have a
bulkhead on the end with the length being determined by the
volume of containment needed.
The system should be cleaned by pumping the collection
manhole 511 and the invert of the drop manhole 52 as often as
conditions require.
Should the likelihood exist for other deleterious
floating particles to cause a blockage in the system, a screen
can be inserted over the surface skimming outlet port 55 such
that the deleterious material is kept in the drop manhole 52 and
out of the oil collection/separation system.
Figures 11 and 12 illustrate a modified form of the
invention. In those figures inlet pipe 61 feeds a runoff of ram
water and oil to inlet tank (or drop manhole) 62. The inlet tank
62 has a weir 63 at the connection between outlet conduit 68 and
inlet tank 62. An open baffle 64 protects the inlet of the
output conduit 68 from a large input flow from pipe 61, and
avoids disturbing the water that is about to enter the outlet
conduit 68. The baffle 64 forms a semi-cylindrical sheet around
the inlet of the outlet conduit 68. All side edges of the baffle
64 may be sealed to the inside wall of the inlet tank 62 to
prevent leakage. The top and bottom ends of the baffle 64 are
open, so that water can flow both over and under baffle 64 on its
way to outlet conduit 68. The open end at the bottom of the
baffle, is well below the level of any surface oil. Since the
oil floats on the water, oil cannot move low enough in tank 62 so
as to enter the open bottom of the baffle 64. Thus, in the

CA 02236354 2004-03-25
absence of a high rate of flow of the incoming water, even if the
outlet 65 becomes clogged, oil will not enter outlet conduit 68
but will build up in inlet tank 62 until that tank is cleaned.
Pipe 610 receives fluid from opening 65 and delivers it to a low
5 level of the main separation tank 611. Further, pipe 612
delivers water from a low level of tank 611 to outlet conduit 68.
The top of weir 63 and the lowermost part of opening 65 are at a
higher level than the output end of pipe 612.
When the stream of water entering inlet pipe 61
10 increases to an intermediate rate of flow, the water will rise to
the elevation of the top of weir 63. Then the baffle 64 will
cause below surface water (without oil) to be forced by gravity
under baffle 64 and over weir 63 to the outlet conduit 68.
Then if there is a heavy flow of liquid such as during
a thunderstorm, the liquid will rise in manhole 62 so that it
crests at a level higher than the baffle 64 and flows directly to
conduit 68 as untreated bypass flow. Meanwhile, the two
previously said flows continue and all oil collected in the
storage or collection manhole 611 remains there until removed
under maintenance by pumping.
When the runoff stream that enters pipe 61 has a very
low rate of flow the fluid level in tank 62 rises until it
overflows into opening 65 that is in the sidewall of tank 62.
This overflow passes to tank 611 and raises the fluid level in
that tank until clean water from the lower half of tank 611
passes through pipe 612 to the output conduit 68.
When the stream of water entering inlet pipe 61 has a
high rate of flow the events described in the immediately
preceding paragraph also happen. In addition, water in tank 62
rises rapidly and overflows weir 63 and directly enters output
conduit 68 without passing through tank 611,
Another form of the invention is carried out if the
inlet tank 12 (Fig. 1) is omitted and inlet pipe 11 connected
directly to the inlet end of outlet conduit 18. The enclosure
28, the weir 13 and pipes 20 and 22 remain but pipes 24 are
omitted. In this form of the invention runoff water entering at

CA 02236354 2004-03-25
11
a relatively low rate builds up and flows over weir 13 and into
enclosure 28. From there the water flows via pipe 20 to the main
separation tank 21. When the fluid in tank 21 rises above the
level of outlet conduit 18, water flows via pipe 22 from tank 21
to the outlet conduit 18. If the runoff water enters at a very
high rate it soon overflows enclosure 28 and passes over roof 25
directly to outlet conduit 18.
Except for the enclosure 28 (Fig. 1) and the parts
associated with that enclosure, all of the separate components of
the invention can be constructed with widely available
construction materials, using well known construction techniques.
Thus, the various parts, individually, of the invention can
readily be fabricated by local contractors using locally
available materials, except as noted above.
My invention is shown and described as a device for
separating oil from rainwater. At least some forms of the
invention may have other applications where it is desirable to
separate fluids of different densities.
As previously explained, the oil remains in the main
separation tank. In all forms of the invention the oil may be
easily removed from that tank by removing the manhole cover over
that tank and pumping the oil from the surface of the tank.
Moreover, all forms of my invention may be easily
cleaned from time to time. To clean the system, the manhole
covers are removed, and the fluid in the tanks pumped out. The
cleaning personnel will then have access to the tanks.
Figure 13 shows a modified form for collecting the
water and oil and delivering them to the main separation tank 21
when the input flow is at a very low rate. Here, the very slow
input flow falls into stub 11a and drains into pipe 11b which in
turn feeds the main separation tank 21. This form of feeding tank
21 may be in addition to, or in place of, the enclosure 28 and
the pipe 20. A further modification involves feeding the inlet
(runoff) water into the open top of the inlet tank.
Figure 14 shows a further modified form of the
invention. The inlet tank 72 receives runoff water (that may

CA 02236354 2004-03-25
12
contain oil) through inlet pipe 71. At very low rates of input
flow, water drains through elliptical opening 75 to pipe 722 to
main separation tank 711. Fluid in tank 72 passes through
opening 75 in the sidewall of tank 72. The lower end of opening
75 is located at a lower level than the upper outlet opening in
conduit 74, and the inlet opening into outlet conduit 78 is at a
higher level than the outlet of conduit 74. Clean water from
tank 711 passes upward through pipe 70 to outlet pipe 78. The
upper end of pipe 70 must be lower than the lower end of opening
75. then there is an intermediate rate of flow entering pipe 71,
the water builds up in conduit 74 until it overflows into outlet
conduit 78. Unlike the pipes 14 in Figure 1, the conduit 74
completely blocks the lower part of the inlet opening to outlet
conduit 78 (as shown in Figure 15) so that until the water builds
up in tank 72 to a level of the top of conduit
74, no water can flow directly into outlet conduit 78 from the
interior of tank 72.
Finally, when there is a very high rate of flow into
tank 72 the main body of the water entering in tank 72 overflows
the top of conduit 74 and passes directly into outlet conduit 78.
The outlet conduit 78 has the shape shown in Figure 14.
The word "manhole" is hereby defined as a hole in the
ground for holding a liquid. The hole may be lined with a wall,
or have a tank in it, so that it will hold the liquid without
leakage.
INDUSTRIAL APPLICABILITY
The invention is applicable where it is desired to
separate fluids of different densities, and more particularly to
cases where runoff water is to be separated from any oil carried
off by the runoff water.

Representative Drawing