Note: Descriptions are shown in the official language in which they were submitted.
HYDRODYNAMIC SEPARATOR
TECHNICAL FIELD
[0001] This application relates generally to separator tanks that
receive stormwater
runoff, and, more particularly, to separator tanks having high sedimentation,
floatables
and/or debris removal and retention even in the case of high flow rates
through their lower
chambers.
BACKGROUND
[0002] The protection of ground water and natural bodies of water
requires systems
for diverting and/or treating water that contacts roadways, parking lots, and
other man-
made structures. If such diversion or treatment systems are not provided,
particulates and
other contaminants located on or forming part of such structures may be
carried by drain
water or stomiwater to the natural water bodies and contaminate them. Local,
state and
federal laws and rules require municipalities, businesses and, in some
instances, private
entities, to establish means to reduce particulate and contaminant levels
permissibly
transferred to natural bodies of water from property under their control.
Particular
requirements may vary from jurisdiction to jurisdiction, but all are likely to
become more,
rather than less, stringent.
[0003] Most new land development plans and upgrades to existing paved
surfaces
involve the insertion of a preliminary separation system, generally for
connection to the
municipal water-handling infrastructure. Any preliminary separation system
should be
designed with the capability to receive fluid flowing in at a wide range of
rates. It is
desirable, then, to have a separation system capable of handling variable
fluid flow rates
with reduced likelihood of backup and flooding of the surface above. It is
also desirable to
control the flow through the system such that trapped particulates are not
scoured or
washed out of the device and re-entrained during high flows for passage
downstream.
[0004] A variety of stomiwater separation systems exist. These
systems generally
include a tank or container including a storage or treatment chamber within
which, ideally,
floating particulates are retained, and non-floating particulates are allowed
to settle. The
storage chamber includes an inlet for receiving untreated water, and an outlet
for
movement of treated water out of the chamber. The tank may also include a
bypass
arrangement to allow excess untreated water to exit the tank without passing
through the
storage chamber. In one implementation of such systems the storage chamber is
located in
1
Date Regue/Date Received 2022-09-23
a lower part of the tank and the bypass is located in an upper part of the
tank, with an insert
or deck located within the tank to separate the two chambers, the insert
having one opening
that defines the storage chamber inlet and another opening that defines the
storage chamber
outlet.
[0005] The device shown in U.S. Patent No. 7,666,303 is exemplary of
such a
separator and utilizes a T-shaped drop tube at the storage chamber inlet to
direct inflows
into the storage chamber, a riser tube at the storage chamber outlet to define
a floatables
collection area in the upper part of the storage chamber and a weir atop the
insert to direct
incoming stormwater to the storage chamber. As flows through the storage
chamber of
such a separator system are increased (e.g., by raising the height of the
weir), less
stormwater flow bypasses, but potential for scouring and washout within the
storage
chamber increases.
[0006] Accordingly, it would be desirable to provide a separator with
increased
treatment flow capacity while at the same time incorporating one or more cost-
effective
features to limit scouring and washout.
SUMMARY
[0007] In one aspect, a separator unit includes a tank defining an
internal volume
and having an inlet and an outlet. An insert within the tank separates the
tank into an upper
chamber and a lower chamber. The insert includes a weir at an upper side of
the insert to
define an inlet side atop the insert for receiving an influent liquid and an
outlet side atop
the insert, a first opening through the insert on the inlet side for
delivering liquid down into
the lower chamber, and a second opening through the insert on the outlet side
for delivering
liquid from the lower chamber back up into the upper chamber. The second
opening is
located substantially centrally on the insert, the weir is formed by a central
curved wall
segment and a pair of lateral wall segments, and the central curved wall
segment extending
along a portion of a peripheral boundary of the second opening.
[0008] In another aspect, a separator unit includes a tank defining
an internal
volume and having an inlet and an outlet. A deck within the tank separates the
tank into an
upper chamber and a lower chamber, with a weir at an upper side of the deck to
define an
inlet side atop the deck for receiving an influent liquid and an outlet side
atop the deck, a
first opening through the deck on the inlet side for delivering liquid down
into the lower
chamber, and a second opening through the deck on the outlet side for
delivering liquid
from the lower chamber back up into the upper chamber. A drop pipe extends
downward
2
Date Regue/Date Received 2022-09-23
from the first opening to a dispersal manifold having a first primary lateral
opening to
direct water laterally into the lower chamber in one direction and a second
primary lateral
opening to direct water laterally into the lower chamber in another direction.
The dispersal
manifold includes a central segment, a first side segment and a second side
segment,
wherein the central segment has a lower wall that is non-perforated and a
first sidewall
facing a near wall of the tank and extending upward from the bottom wall and
that is
perforated.
[0009] In yet another aspect, a separator unit includes a tank
defining an internal
volume and having an inlet and an outlet. A deck within the tank separates the
tank into an
upper chamber and a lower chamber, with a weir at an upper side of the deck to
define an
inlet side atop the deck for receiving an influent liquid and an outlet side
atop the deck, a
mount opening through the deck on the inlet side, and another opening through
the deck on
the outlet side. A drop pipe assembly is connected to the mount opening, and
the drop pipe
assembly includes an upper support plate, a drop pipe and a dispersal manifold
integrated
as a unit. The upper support plate has a periphery that sits atop the mount
opening, and an
opening is formed in the upper support plate to deliver liquid into the drop
pipe.
[0010] In a further aspect, a separator unit includes a tank defining
an internal
volume and having an inlet and an outlet. A deck within the tank separates the
tank into an
upper chamber and a lower chamber, with a weir at an upper side of the deck to
define an
inlet side atop the deck for receiving an influent liquid and an outlet side
atop the deck, a
first opening through the deck on the inlet side for delivering liquid down
into the lower
chamber, and a second opening through the deck on the outlet side for
delivering liquid
from the lower chamber back up into the upper chamber. A riser pipe extends
downwardly
into the lower chamber from the second opening, wherein the riser pipe
includes at least
one vortex disrupting vane extending inwardly from an inner surface of the
riser ripe.
[0011] In another aspect, a hydrodynamic separator unit for treating
stormwater
flows includes a tank defining an internal volume and having an inlet and an
outlet, the
tank being of right circular cylinder shape to define a tank diameter. A deck
within the
tank separates the tank into an upper chamber and a lower chamber, with a weir
at an upper
side of the deck to define an inlet side atop the deck for receiving an
influent liquid and an
outlet side atop the deck, a first opening through the deck on the inlet side
for delivering
liquid down into the lower chamber, and a second opening through the deck on
the outlet
side for delivering liquid from the lower chamber back up into the upper
chamber. A drop
3
Date Regue/Date Received 2022-09-23
pipe extends downward from the first opening and is of a conical shape such
that a bottom
opening of the drop pipe is smaller than the first opening, wherein a diameter
of the first
opening is between about 10% and 12% of the tank diameter, and a diameter of
the bottom
opening is between about 8% and 10% of the tank diameter. The second opening
is located
substantially centrally within the tank, the weir is formed by a central
curved wall segment
and a pair of lateral wall segments, the central curved wall segment extending
along a
portion of a peripheral boundary of the second opening, wherein each lateral
wall segment
is substantially planar in shape and extends from the central curved wall
segment to an
inside surface of the tank, wherein the lateral wall segments are positioned
such that an
arcuate extent of the inlet side of the deck is about two-hundred forty
degrees. A riser pipe
extends downward from the second opening, wherein a diameter of the second
opening and
the riser pipe is between about 30% and 35% of the tank diameter.
[0012] In yet another aspect, a method of providing multiple sizes of
separator
units, comprises: utilizing a consistent separator unit configuration among
multiple sizes,
wherein the separator unit configuration comprises a tank defining an internal
volume and
having an inlet and an outlet, the tank being of right circular cylinder shape
to define a tank
diameter that specifies the size of the separator unit, a deck within the tank
and separating
the tank into an upper chamber and a lower chamber, a weir at an upper side of
the deck to
define an inlet side atop the deck for receiving an influent liquid and an
outlet side atop the
deck, a first opening through the deck on the inlet side for delivering liquid
down into the
lower chamber, and a second opening through the deck on the outlet side for
delivering
liquid from the lower chamber back up into the upper chamber, a drop pipe
extending
downward from the first opening and having a conical shape such that a bottom
opening of
the drop pipe is smaller than the first opening, and a riser pipe extending
downward from
the second opening; and for each of the multiples sizes, setting each of (i) a
diameter of the
first opening as a first consistent function of the tank diameter, a diameter
of the bottom
opening as a second consistent function of the tank diameter, and (iii) a
diameter of the
second opening as a third consistent function of the tank diameter.
[0013] In still another aspect, a separator unit includes a tank
defining an internal
volume and having an inlet and an outlet. An insert is located within the tank
and separates
the tank into an upper chamber and a lower chamber. The insert includes a weir
at an
upper side of the insert to define an inlet side atop the insert for receiving
an influent liquid
and an outlet side atop the insert. A first opening through the insert is on
the inlet side for
4
Date Recue/Date Received 2022-09-23
delivering liquid down into the lower chamber, and a second opening through
the insert is
on the outlet side for delivering liquid from the lower chamber back up into
the upper
chamber. The second opening is located along a perimeter of the insert and
defined in part
by a wall of the tank.
[0014] In another aspect, a separator unit includes a tank defining
an internal
volume and having an inlet and an outlet, the tank including a wall of
substantially a right
circular cylinder shape. An insert within the tank separates the tank into an
upper chamber
and a lower chamber, the insert including a deck and a downwardly extending
perimeter
wall. A weir at an upper side of the deck defines an inlet side atop the deck
for receiving
an influent liquid and an outlet side atop the deck. A first opening through
the deck is on
the inlet side for delivering liquid down into the lower chamber, and a second
opening
through the deck is on the outlet side for delivering liquid from the lower
chamber back up
into the upper chamber. The second opening is formed at a perimeter of the
insert and a
segment of the perimeter wall that runs along the second opening combines with
the wall
of the tank to form a riser path up out of the lower chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Fig. 1 is a perspective view of one embodiment of a separator
unit;
[0016] Figs. 2 is a cross-section view of the separator unit of Fig.
1 along a vertical
plane to one side of the center of the separator;
[0017] Fig. 3 is a cross-section view of the separator unit of Fig. 1
along a vertical
plane passing through the center of the separator;
[0018] Fig. 4 is a perspective internal view of the separator with a
top portion of the
tank removed;
[0019] Fig. 5 is a top plan view of Fig. 4;
[0020] Figs. 6, 7 and 8 are perspective views of the deck insert of
the separator,
with inlet and outlet pipes also shown;
[0021] Fig. 9 is a top down cross-section view of the separator taken
along a
horizontal plane below the deck;
[0022] Figs. 10 and 11 are perspective views of a deck of the
separator;
[0023] Fig. 12 is an exploded perspective view of the deck insert
including the deck
and primary deck insert components;
[0024] Fig. 13 is a perspective view of a drop pipe assembly of the
deck insert;
Date Recue/Date Received 2022-09-23
[0025] Figs. 14 and 15 are perspective views of another embodiment of
a deck
insert;
[0026] Fig. 16 is an exploded perspective view of the deck insert of
Fig. 14;
[0027] Fig. 17 is partial cross-section of a separator unit
incorporating the deck
insert of Fig. 14, with the tank shown in dashed line fonn;
[0028] Fig. 18 is a top plan view of the deck insert of Fig. 14; and
[0029] Fig. 19 is a perspective view of another embodiment of deck.
DETAILED DESCRIPTION
[0030] Referring to Figs. 1-13, a separator 5 includes a tank 10 with
an upper
manhole access port 11, and in internal deck insert 12 that divides the tank
into an upper
chamber 14 and a lower chamber 16. The deck insert 12 may, by way of example,
be of
fiberglass construction and be attached to the tank sidewalls by brackets,
fasteners or other
suitable structure, but other variations are possible. The tank 10 includes
one or more
sidewall inlets 18 and a sidewall outlet 20. Exemplary inlet pipe 90 and
outlet pipe 92 are
shown connected to the inlet and outlet respectively. In one example the tank
may be of
cylindrical (e.g., a right circular cylinder) concrete manhole type
configuration, but other
tank structures are possible. The insert 12 includes a weir 22 that extends
upward from the
upper surface of the deck and across the deck from one location on the tank
sidewall to
another so as to divide the top of the insert into an upstream (inlet) side 24
and a
downstream (outlet side) 26. In the illustrated embodiment, the weir divides
the top of the
insert into an upstream side 24 of approximate arc of 240 and a downstream
side 26 of
approximate arc of 120 and thereby accommodates multiple inlet pipes and a
wide range
of inlet and outlet angles, largely dependent on unit diameter, pipe diameter
and pipe
material of construction.
[0031] The inlet side 24 of the insert may be sloped toward an
opening 30 of the
insert that leads down to the lower chamber 16 to deliver incoming water to be
treated into
the lower chamber 16. Such sloping reduces the potential for sediment
accumulation on
the top side of the deck, and increases capture of both sediment and gross
pollutants that
may settle on the deck's surface during an event by directing these pollutants
into the drop
pipe inlet opening 30 as flows subside. Water passing through the lower
chamber exits the
lower chamber through an opening 32 (with associate riser pipe 82) on the
opposite side of
the weir 22. Notably, the flow outlet opening 32 from the lower chamber 16 is
substantially centered on a central axis 34 of the cylindrical tank 10. The
weir 22 is formed
6
Date Regue/Date Received 2022-09-23
by a central arcuate wall segment 36 and a pair of lateral wall segments 38
extending
outward from the central segment 36. The central arcuate wall segment 36
extends along a
portion of a peripheral boundary of the opening 32 and has a convex surface
side 51 facing
toward the inlet 18 of the tank and a concave surface side 53 facing toward
the upright axis
34 of the tank and opening 32. Here, the central arcuate wall segment 36
extends through
at least two-hundred circumferential degrees (e.g., at least two-hundred
twenty
circumferential degrees, such as two-hundred forty circumferential degrees),
and each
lateral wall segment 38 extends generally linearly and is planar in
configuration. Here, the
central wall segment 36 also has a top edge that is higher than the top edge
of either of the
lateral wall segments 38. The height of the straight wall segments 38 of the
weir above the
outlet pipe 92 invert 93 may vary depending on the design surface loading rate
of the
device or any tailwater conditions within the stormwater network, and may
typically be
about 15 inches, but can vary as desired. The height of the curved arcuate
central segment
of the weir may be about 6 inches above the elevation of the straight wall
portions of the
weir.
[0032] Notably, the diameter of the opening 32, and similarly the
effective diameter
of the arcuate wall segment 36, may be suitably sized for access to the lower
chamber 16
for cleanout using a suction pipe or hose, but may also be sized to enable a
person to access
the lower chamber if needed (e.g., a diameter of 20 inches or more, such as 24
inches).
Thus, the opening 32 serves the dual purpose of both functioning as the outlet
flow opening
from the lower chamber and functioning as the primary cleanout and/or
maintenance access
opening to the lower chamber.
[0033] A drop pipe 40 extends downward from the opening 30 to a
dispersal
manifold 42 for delivering water into the lower chamber 16. The dispersal
manifold 42 has
a unique and advantageous configuration for separator performance. In
particular, the
dispersal manifold has opposite primary lateral openings 44 to direct water
laterally into
the lower chamber 16 in respective opposite lateral directions (represented by
arrows 46 in
Fig. 9). The dispersal manifold 42 is made up of a central segment 50 and two
side
segments or wings 52, where the side segments are substantially arcuate, and
each have a
convex surface side facing toward the inlet side of the tank wall or near
location of the tank
wall and a concave surface side facing toward the riser pipe 82. As best seen
in Figs. 7-9,
here, the central segment has a bottom floor or wall 54, an outwardly facing
sidewall 56
and an inwardly facing sidewall 58 extending upward from the bottom wall,
where the
7
Date Regue/Date Received 2022-09-23
bottom floor or wall 54 is non-perforated, the outwardly facing sidewall 56 is
perforated
and the inwardly facing sidewall 58 is non-perforated. Each side segment 52 of
the
dispersal manifold includes a respective bottom floor or wall 60 and outwardly
and
inwardly facing sidewalls 62 and 64, where the bottom wall 60 is perforated
and the
sidewalls 62 and 64 are not perforated, with sidewall 62 forming the convex
surface side of
the side segment that faces the inlet side of the tank wall and with sidewall
64 forming the
concave surface side of the side segment that faces the riser pipe. The top
wall 66 of the
cential segment is non-perforated (but includes an opening with which the drop
pipe 40
connects), and the top walls 68 of the respective side segments are also non-
perforated.
[0034] Notably, the upper inlet section of the drop pipe 40 has a
circular opening
and a the drop pipe 40 is of conical shape (reducing in diameter when moving
downward)
favorable for creating a vortex to enhance pollutant capture by pulling
pollutants into the
lower treatment chamber 16. The bottom of the cone-shaped drop pipe 40 is
connected to
the top wall of central segment 50 of the dispersal manifold or duct 42. The
central
segment and side or wing segments of the dispersal manifold have perforated
and non-
perforated walls as described above. The two rectangular primary outlet
openings 44 of the
side segments or wings, combined with the secondary perforations in the
outwardly facing
wall of the central segment and the secondary perforations in the floor of
each side
segment, allow the dispersal manifold to diffuse the influent flow in multiple
directions and
at lower average discharge velocity into the lower treatment chamber 16, as
compared to a
similar drop pipe and dispersal manifold arrangement without any perforations.
The
diffusion of influent flow in multiple directions and at lower average
discharge velocity is
favorable for removal of sediment and floatable pollutants such as oil, and is
favorable for
reducing scour and washout of previously captured sediment. Additionally, the
perforations
in the bottom wall or floor 60 of each side segment or wing of the dispersal
manifold
prevent sediment from accumulating on the floor of each side segment which
might
otherwise cause eventual clogging and flow restriction in a similar
arrangement without
perforations.
[0035] Referring to Figs. 10-13, the deck insert is made up of a
number of primary
components, including a molded deck 80 (e.g., of fiberglass as described
above), the weir
wall segments 36 and 38, a riser pipe 82, an oil port pipe 84, and a drop pipe
assembly 70
formed by integration of the drop pipe 40 and dispersal manifold 42. The oil
port pipe 84
connects to an oil port stub 85 of the deck, and the height of the oil port
pipe is set to
8
Date Regue/Date Received 2022-09-23
prevent water atop the deck from entering the oil port pipe during even bypass
conditions
within the separator. The riser pipe 82 fits down into the deck opening 32 and
can be
connected by suitable fasteners. For this purpose, the deck 80 includes a part
conical rim
33 defining the opening 32, and the riser pipe 82 includes a part conical top
flange 83 that
is sized to sit within and against the rim 33, and two conical portions can be
bolted
together. The arcuate wall segment 36 of the weir fits within a similarly
shaped arcuate
boundary 35 of the opening 32 above the rim 33 and can be bolted thereto
and/or connected
to the lateral wall segments 38 for support. The deck includes an upper
surface drop from
the inlet side to the outlet side of the weir, forming a pair of angled steps
39, and the lower
portion 41 of each lateral wall segment 38 of the weir is angled slightly to
match the angle
of the step 39 so that the angled portions sit adjacent each other. Bolts can
be passed
between the two angled portions 41 and 39 to connect the lateral wall segments
38 to the
deck 80. Brackets 43 at the outer edges of the segments 38 connect to the tank
walls.
[0036] The molded deck 80 includes a drop inlet opening 86 that is
suitably sized to
enable the lower portion of the drop pipe assembly 70 to be passed through the
opening 86,
and the opening 86 is bounded by a slight recess 88 in the upper surface of
the deck that is
configured to match a configuration of an upper support plate 94 of the drop
pipe assembly
70. Notably, the peripheral shape of the recess 88 and the peripheral shape of
the support
plate 94 are non-symmetrical to assure desired orientation of the drop pipe
assembly unit
70 when assembled to the deck 80 (e.g., using bolts or other suitable
fasteners). The
attachment bolts are removable and thereby allow for removal of the drop unit
70 for
inspection and maintenance. Of course, alternative methods of mechanical
attachment of
the drop pipe other than bolting to the deck may be used to secure the drop
pipe assembly
in position. Here, the support plate 94 defines the opening 30 to the lower
chamber.
[0037] The circular opening 30 and conical shape of the inlet section
of the drop
pipe 40 is favorable for formation and sustenance of a vortex above the inlet
opening 30
that enhances pollutant capture by pulling the pollutants into the treatment
chamber. The
drop pipe 40 is positioned such that the circular inlet opening 30 is not in
the direct path of
influent flow from the inlet pipe (as best seen in Fig. 5), thereby enhancing
the formation
and sustenance of a strong vortex above the inlet opening 30 of the drop pipe
that might
otherwise be disrupted if the circular inlet opening was directly in the
influent flow path.
The entrance edge of the circular inlet opening 30 of the drop pipe may be of
variable
rounding to reduce the pressure drop across the inlet opening and increase
flow rate
9
Date Recue/Date Received 2022-09-23
entering the drop pipe 40.
[0038] The cone-shape of the drop pipe 40 assures that the circular
top opening 30
of the cone shaped drop pipe is of larger diameter than the circular bottom
opening of the
drop pipe. Thus, the bottom opening of the drop pipe 40 serves as the
treatment flow
control orifice for the separator unit, and the diameter of the top and bottom
openings of
the cone-shaped drop pipe may be set as desired to achieve the target design
flow rate into
the treatment chamber 16 and to modify the vortex strength within the cone-
shaped drop
pipe 40. The vertical length of the drop pipe 40 may be set as desired to
discharge the
influent at the desired elevation within the treatment chamber 16. The
dimensions of the
rectangular primary outlet openings 44 and the perforations of the dispersal
manifold 42
may be set as desired to modify the average discharge velocity of influent
flow into the
treatment chamber 16.
[0039] The cylindrical riser pipe 82 extends downward from opening 32
into the
lower treatment chamber 16, and is centrally located in the treatment chamber
based upon
the central position of the opening 32. Effluent from the lower treatment
chamber 16
enters the lower opening of the riser pipe 82 and discharges from the upper
opening of the
riser pipe onto the top surface the deck downstream of the weir 22. The
diameter of the
riser pipe is at least 1/2 the radius r16 of the lower treatment chamber 16,
such as about 2/3
the radius of the lower treatment chamber. The length of the riser pipe 82 may
be set in
conjunction with the depth of the treatment chamber 16 to increase or decrease
pollutant
storage volumes, and is typically a minimum 12 inches in length. An annular
channel 96 of
substantially uniform annular width W96 is thus formed in the treatment
chamber
surrounding the riser pipe 82, and the annular channel width W96 may be about
2/3 the
radius of the lower treatment chamber (in cases where the diameter of the
riser pipe 82 is
2/3 as suggested above).
[0040] In one implementation, where the tank is in the form of a
right circular
cylinder that defines a tank diameter, desirable scalability of the separator
configuration is
achieved by maintaining an arcuate inlet side 24 above the deck at between
about 235 and
245 degrees and setting each of a diameter of the opening 30 (the top opening
of the
conical drop pipe) as a first consistent function of the tank diameter, a
diameter of the
bottom opening of the conical drop pipe as a second consistent function of the
tank
diameter, and a diameter of the opening 32 as a third consistent function of
the tank
diameter. Preferably, the first consistent function sets the diameter of the
opening 30 to
Date Regue/Date Received 2022-09-23
between about 10% and 12% of the tank diameter, the second consistent function
sets the
diameter of the bottom opening to between about 8% and 10% of the tank
diameter, and
the third consistent function sets the diameter of the opening 32 to between
about 30% and
35% of the tank diameter. These functions/design parameters allow for
consistency across
a broad range of tank diameters, such 3, 4, 5, 6, 7, 8, 10 and 12 foot
standard manhole
diameters, as well as other diameters.
[0041] Incoming water to the treatment chamber 16 flows down the drop
pipe 40
into the dispersal manifold 42 and flows out from the rectangular outlet
openings 44 of
dispersal manifold and discharges in an approximately tangential direction
relative to the
near portion of treatment chamber wall. Flow through the perforations in the
outwardly
facing side wall 56 of the central segment 50 of the dispersal manifold is
discharged
outwardly away from the center of the treatment chamber toward the near wall
of the
treatment chamber. Flow through the perforations in the bottom wall or floor
60 of each
wing or side segment 52 of the dispersal manifold is discharged toward the
bottom of the
treatment chamber. Floatables, such as oil and gross pollutants, rise up
within the channel
96 surrounding the riser pipe 82 and are trapped beneath the deck. Sediment
settles to the
floor of the treatment chamber 16. Effluent from the treatment chamber enters
the lower
end of the riser pipe 82. Due to the relatively large diameter of the riser
pipe opening, the
velocity of the stream entering the lower opening of the riser pipe 82 is
relatively low, and
thereby enhances sediment removal and reduces the probability of increased
velocities
within the water column and resuspension of previous captured sediment from
the sump.
As mentioned above, the central riser pipe 82 also serves as the primary
inspection access
and maintenance access port, and provides adequate access for insertion of
both a vacuum
hose and spray wand to remove accumulated sediment and floatable pollutants.
[0042] A vertically oriented vortex-disrupting vane 98 is installed
within the riser
pipe 82, and prevents the formation of a vortex within the riser pipe 82 that
might
otherwise occur at high flow rates in a riser pipe without the vortex-
disrupting vane, and
thereby prevents the potential scour and washout of previously captured
sediment that such
a vortex might induce. The vortex-disrupting vane may be comprised of a
flexible material,
such as a single row or multiple rows of polymeric filaments, or a polymeric
blade. The
vertical length of the vane 98 may typically be at least one-half the length
of the riser pipe,
but may be lesser or greater as needed to effect vortex disruption. The
distance the vane
extends inwardly from the inside wall of the riser pipe 82 may typically be at
least about
11
Date Recue/Date Received 2022-09-23
one-half the radius of the riser pipe, but may be lesser or greater as needed
to effect vortex
disruption. A single vane 98 or multiple vanes may be installed to effect
vortex disruption.
The attachment of the vane to the riser pipe may be by bolting or gluing or
other suitable
means of mechanical attachment. The flexible nature of the vane allows
maintenance
activities, such as vacuuming and rinsing of the treatment chamber, to occur
with minimal
interference and with minimal damage to the vane 98.
[0043] Some embodiments may utilize an inlet grate and frame (e.g.
represented by
dashed line form 110 in Fig. 1) embedded in the precast concrete top slab 112
of the tank in
order to direct runoff into the treatment unit from above. In such cases, an
optional
removable flow deflector may be attached to the precast concrete top slab and
beneath the
inlet grate and frame, where the removable flow deflector channels inlet grate
runoff onto
the surface of the deck upstream of the weir (i.e., on the inlet side 24), and
allows favorable
positioning of the inlet frame and grate, and easy removal of the flow
deflector, to facilitate
inspection and maintenance. The flow deflector functions as a chute to convey
and direct
the runoff, and may be of varying width, length, and angle as needed to
accommodate
specific inlet frame dimensions and frame elevation above the insert weir.
[0044] In operation, the inlet pipe 90 (or in some case multiple
inlet pipes or top
grate inlet, or a combination of these) delivers stormwater influent to the
top of the deck
insert 12 on the upstream side 24 of the weir 22. A pond of variable depth
depending on
influent flow rate is formed on the upstream topside 24. Influent exiting the
inlet pipe(s)
90 immediately contacts the pond, which serves to attenuate the water velocity
for a wide
range of inlet pipe entrance slopes (e.g., 8 degrees downward angle from
horizontal) and
inlet pipe angles as flow moves toward the upstream side of the weir 22, and
thereby
reduces the potential for "hydraulic jump" over the weir 22. Additionally, the
curved and
elevated partially-cylindrical central segment 36 of the weir serves to split
the flow exiting
the primary inlet pipe 90, thereby preventing hydraulic jump over the central
portion of the
weir.
[0045] Influent is conveyed into the inlet opening 30 of the drop
pipe 40. The
circular opening 30 and conical shape of the drop pipe 40, and offset location
of the drop
pipe inlet opening 30, are favorable for formation and sustenance of a vortex
above the
inlet opening 30 that enhances pollutant capture by pulling the pollutants
into the treatment
chamber 16. Influent is conveyed down through the drop pipe 40 into the
dispersal
manifold 42. Flow from the primary rectangular outlet openings 44 of each
lateral or wing
12
Date Regue/Date Received 2022-09-23
segment 52 of the dispersal manifold discharges in an approximately tangential
direction
relative to the near wall of the treatment chamber 16. Flow through the
perforations in the
outwardly facing sidewall 56 of the central segment 50 of the manifold 42 is
discharged
toward the near wall of the treatment chamber. Flow through the perforations
in the
bottom wall or floor of each side or wing segment 52 of the manifold is
discharged toward
the bottom of the treatment chamber 16. Floatables, such as oil and gross
pollutants, rise up
within the annular channel 96 surrounding the riser pipe 82 and are trapped
beneath the
deck 80. Sediment settles to the floor of the treatment chamber. Effluent from
the
treatment chamber enters the lower end of the riser pipe 82. The vortex-
disrupting vane 98
within the riser pipe 82 prevents formation of a vortex within the riser pipe
during high
flow rates, thereby preventing scour and washout of previously captured
sediment.
Effluent from the lower treatment chamber 16 flow up through the riser pipe
onto the top
side of the deck at the downstream side 26 of the weir, and is delivered out
the outlet pipe
92.
[0046I The flow rate into the lower treatment chamber 16 is a
function of the water
elevation on the upstream side 24 of the weir 22 and the area of the bottom
opening of the
cone-shaped drop pipe 40. During storm events with very high influent flow
rates, the
water elevation on the upstream side 24 of the weir 22 may exceed the height
of the weir,
and the excess flow passes over the top of the weir (e.g., over the top of the
two lateral weir
wall segments 38) to the downstream side 26 of the deck, and exits through the
outlet pipe.
This is an "internal bypass" feature.
[0047] When inspection or maintenance cleaning is performed, a
measuring stick or
vacuum hose is inserted through the centrally located riser pipe 82 to measure
or remove
sediment from the lower treatment chamber 16. For hydrocarbon presence,
measurement
and removal, inspection and maintenance can be performed through the oil
inspection port
84. As a supplemental inspection and maintenance procedure, the drop pipe unit
70 may
be removed and a vacuum hose or rinsing wand inserted through the deck opening
86 to
access accumulated sediment in the sump. Having multiple openings for
maintenance
access provides capability for more thorough cleaning of the device.
[0048] It is to be clearly understood that the above description is
intended by way
of illustration and example only, is not intended to be taken by way of
limitation, and that
other changes and modifications are possible. For example, in some
implementations the
deck portion of the insert, as well as other portions, may be formed as an
integral or unitary
13
Date Regue/Date Received 2022-09-23
part of a separator tank (e.g., where a tank is of molded plastic
configuration, or where the
deck is formed of concrete cast with a concrete manhole structure).
Regardless, the overall
configuration of the separator provides one or more advantageous features,
such as
increasing the design surface loading rate into the treatment chamber;
increasing the vortex
strength above the inlet opening to the treatment chamber by using a conically
shaped drop
pipe, thereby improving capability to pull pollutants down into the treatment
chamber and
improve sediment, oil and floatables capture; reducing disruption to the
vortex above the
inlet opening to the treatment chamber by offsetting the inlet opening such
that it is not in
the direct path of influent flow from the inlet pipe; increasing sediment
removal efficiency
by diffusion of the influent stream in multiple directions into the treatment
chamber
through a perforated outlet section on the dispersion manifold at the bottom
of the drop
pipe; increasing sediment removal efficiency and reducing scour potential at
high surface
loading rates by eliminating the vortex in the cylindrical riser pipe by use
of a vortex-
disrupting vane within the riser pipe; providing capability for a single inlet
pipe or multiple
inlet pipes with a single insert design, and flow entry from the surface via
an inlet grate at
grade; providing a centrally located primary maintenance cleanout port of
sufficient size
for vactoring and rinsing of the treatment chamber; providing a primary
maintenance
cleanout port that does not require removal of a drop pipe to gain maintenance
access;
attenuating influent water velocity at larger inlet pipe slopes as flow exits
the inlet pipe and
enters the upper chamber by increasing ponding volume over the insert upstream
of the
weir, thereby enhancing sediment removal and reducing the potential for
"hydraulic jump"
over the insert weir; providing a partially-cylindrical and elevated curvature
in the central
portion of the weir that serves to reduce the potential for "hydraulic jump"
over the weir;
providing a sloping deck top surface upstream of the weir that minimizes
accumulation of
pollutants on the surface of the insert and allowing flushing of pollutants
into the inlet to
the treatment chamber as storms subside; and/or providing an optional
removable flow
deflector that attaches to the precast concrete top slab and beneath an inlet
grate and frame,
the removable flow deflector channeling inlet grate runoff onto the surface of
the insert
upstream of the weir, and allowing favorable positioning of the inlet grate
and frame, and
easy removal of flow deflector, to facilitate inspection and maintenance.
[0049] Other variations are also possible.
[0050] Referring to Figs. 14-17, another embodiment of a deck insert
212 for a
separator unit 205 that includes a tank 210 is shown, where the tank includes
inlet pipe 290
14
Date Regue/Date Received 2022-09-23
and outlet pipe 292. The insert 212 includes a weir 222 that extends upward
from the
upper surface of the deck and across the deck from one location on the tank
sidewall to
another so as to divide the top of the insert into an upstream (inlet) side
224 and a
downstream (outlet side) 226. Similar to above, n the illustrated embodiment,
the weir
divides the top of the insert into an upstream side 224 of approximate arc of
2400 and a
downstream side 226 of approximate arc of 120 and thereby accommodates
multiple inlet
pipes and a wide range of inlet and outlet angles, largely dependent on unit
diameter, pipe
diameter and pipe material of construction.
[0051] The inlet side 224 of the insert may be sloped toward an
opening 230 of the
insert that leads down to the lower chamber 216 to deliver incoming water to
be treated
into the lower chamber 216. Water passing through the lower chamber exits the
lower
chamber through an opening 232 (with associate riser pipe 282) on the opposite
side of the
weir 222. Notably, the flow outlet opening 232 from the lower chamber 216 is
at the
perimeter of the insert and is formed in part by a wall of the tank 210. This
arrangement
maximizes the distance between the inlet 230 and the outlet 232. The riser
pipe 282 is
formed by a wall segment 283 that extends downward from is unitary with the
upper deck
surface of the insert. Thus, the riser path or upflow path from lower chamber
216 is
formed in part by the wall segment 283 and in part by the wall of the tank.
Here, the wall
segment or portion 283 is U-shaped, with substantially planar side segments
285 and a
curved central segment 287, and a convex side of the curved central segment
287 faces
toward a center axis 300 of the tank. Notably, a perimeter wall 275 extends
downward
from the upper deck portion of the insert and follows the entire perimeter of
the insert,
which facilitates mounting to and sealing against the tank wall. Wall segment
283 is
simply a segment of the overall continuous perimeter wall 275. As seen in Fig.
18, a vane
298 may be included in the riser path, and is here connected to wall segment
283,
specifically the center of the curved central segment 287. As described above,
the vane
prevents formation of vortex flows within the riser path.
[0052] The weir 222 is formed as a single piece with a V-shape that
defines lateral
wall segments 223 and 225 angled relative to each other to Timm the V-shape,
with the
vertex 227 pointing away from the outlet of the tank. The deck of the insert
is formed with
a pair of angled step-downs 231 and 233 from the inlet side to the outlet
side, which step-
downs form a similar V-shape, and each lateral wall segment 223 and 225 has a
lower
portion 223-1 and 225-1 that is angled and mated to a respective one of the
angled step-
Date Regue/Date Received 2022-09-23
downs of the deck. Notably, the central portion of the weir 222, formed by the
vertex
adjoining sides of wall segments 223 and 225, is higher than the outer
portions of the weir.
The weir configuration creates split flows of the incoming water, which flows
swirl back
atop the deck and push pollutants toward the vortex flow formed at the opening
230, per
flow arrows 237 in Fig. 18. The weir configuration also mitigates hydraulic
jump (over the
weir) at medium and high flows through the separator unit. Weir extensions
(for higher
height) could be installed at the manufacturing location or at an install
site.
[0053] As seen in Fig. 16, the insert 212 utilizes less parts, and
requires less
assembly than the insert 12. With the exception of the shape of upper support
plate 294,
the drop pipe assembly 270, including dispersion manifold 242, is of the same
configuration as drop pipe assembly 70 and dispersion manifold 242 described
above, and
therefore provides similar functions and advantages. The recess 288
surrounding the drop
inlet opening 286 in the deck is shaped to match upper support plate 294.
[0054] An oil port stub 285 is located on the outlet side 226 of the
weir 222, and an
oil port pipe 284 connects thereto.
[0055] Referring to Fig. 19, in another variation the wall segment
283' forming the
riser pipe may extend downward further than a remainder of the perimeter wall
275' of the
deck unit. This extended riser pipe version can be used for systems in which a
larger
floatables capture volume below the deck is desired. As also shown, a grate
unit 310 may
be positioned over the outlet opening 232 to provide a standing platform that
can be used
during maintenance activities of the separator. The grate may be hingedly
connected to the
deck (e.g., about a horizontal hinge axis 312 at one end) to enable pivot
between the
illustrated lowered position and a raised position, per arrow 314. The hinged
connection
may include a lock or latch system to hold the grate in the raised position
when desired.
Moreover, and particularly in the case of larger grate sizes, the grate itself
may be made of
two or more hinge dly connected pieces in order to enable the grate to fold
upon itself if
needed to avoid any interference with the top of the separator when the grate
is raised.
16
Date Regue/Date Received 2022-09-23
