NZ741663B2 - Underdrain Assembly - Google Patents
Underdrain Assembly Download PDFInfo
- Publication number
- NZ741663B2 NZ741663B2 NZ741663A NZ74166314A NZ741663B2 NZ 741663 B2 NZ741663 B2 NZ 741663B2 NZ 741663 A NZ741663 A NZ 741663A NZ 74166314 A NZ74166314 A NZ 74166314A NZ 741663 B2 NZ741663 B2 NZ 741663B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- underdrain
- water inlet
- air
- assembly
- water
- Prior art date
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 97
- 238000001914 filtration Methods 0.000 claims abstract description 70
- 239000012530 fluid Substances 0.000 claims abstract description 49
- 238000009826 distribution Methods 0.000 description 19
- 230000007246 mechanism Effects 0.000 description 10
- 230000000712 assembly Effects 0.000 description 7
- 238000000429 assembly Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000005755 formation reaction Methods 0.000 description 5
- 239000003351 stiffener Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 230000035939 shock Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 210000005069 ears Anatomy 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
- B01D24/10—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being held in a closed container
- B01D24/12—Downward filtration, the filtering material being supported by pervious surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
- B01D24/20—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being provided in an open container
- B01D24/24—Downward filtration, the container having distribution or collection headers or pervious conduits
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/46—Regenerating the filtering material in the filter
- B01D24/4631—Counter-current flushing, e.g. by air
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
-
- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03F—SEWERS; CESSPOOLS
- E03F1/00—Methods, systems, or installations for draining-off sewage or storm water
Abstract
underdrain assembly for filtering particulates from a fluid having an upper structure connected to a bottom plate. At least one flow control vane is positioned between the upper structure and the bottom plate for directing and managing fluid flow through the assembly. The upper structure can have first and second filtration members, the second filtration member positioned between the first filtration member and the bottom plate. The second filtration member can have a shape that restricts fluid flow within the underdrain. The underdrain can have air and water inlets. The water inlet can have an end with a plate covering an upper portion thereof. The end can also include an opening having an angular cut forming an angle with respect to a longitudinal axis of the water inlet. Thus arranged, air is prevented from migrating out the water line. A resilient mounting arrangement for the underdrain is also disclosed. first and second filtration members, the second filtration member positioned between the first filtration member and the bottom plate. The second filtration member can have a shape that restricts fluid flow within the underdrain. The underdrain can have air and water inlets. The water inlet can have an end with a plate covering an upper portion thereof. The end can also include an opening having an angular cut forming an angle with respect to a longitudinal axis of the water inlet. Thus arranged, air is prevented from migrating out the water line. A resilient mounting arrangement for the underdrain is also disclosed.
Description
UNDERDRAIN ASSEMBLY
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to pending U.S. Provisional Patent Application
Serial No. 61/765,375 filed February 15, 2013, the entirety of which provisional application
is incorporated by reference herein.
BACKGROUND OF THE INVENTION
Field of the Invention
Embodiments of the invention generally relate to an assembly and method of
filtration. More specifically, the invention relates to an assembly and method for underdrain
filtration.
Description of the Related Art
Underdrain assemblies are designed to filter various particulates from large
volumes of fluid, such as water. In general, "dirty" water is sent through filter media to help
remove particulates, and reaches a plurality of underdrains that are designed to keep the filter
media out, yet allow for the water to drain into and through the underdrain. Each underdrain
has an opening that leads to a centralized trench that collects all filtered water, and the
filtered water is eventually removed from the trench. Underdrain assemblies may also allow
water to be backwashed for cleaning and/or filtering purposes. During the backwash
process, water may be injected into the centralized trench, moved up through the plurality of
underdrains, and out through the filter media.
SUBSTITUTE SHEET (RULE 26)
Ideally, fluid is evenly distributed throughout the length of an underdrain, and
fluid flow rates are steady throughout the length of the underdrain into the trench. However,
underdrain assemblies have increased in size over the years, and the distribution of fluid and
fluid flow through the underdrain assemblies have become problematic. In addition, the
design of current flume plates, which support underdrains on top of trenches, may lead to
issues when fluid moves from the underdrains into the trench, and installing extended lengths
of underdrain assemblies have also become more challenging.
What is needed is an assembly and method of underdrain filtration that avoids
problems associated with current underdrain assemblies.
SUMMARY OF THE INVENTION
In one embodiment, the invention generally relates to an underdrain apparatus
that includes an upper structure for filtering particulates from a fluid which is connected to a
bottom plate. At least one flow control vane is positioned between the upper structure and
the bottom plate.
In one embodiment, the invention relates to an underdrain apparatus comprising
an upper structure for filtering particulates from a fluid and a bottom plate connected to the
upper structure. The upper structure includes a first filtration member and a second filtration
member, wherein the second filtration member is positioned between the first filtration
member and the bottom plate and includes a formation that restricts fluid flow within the
underdrain.
In one embodiment, the invention relates to an underdrain assembly comprising a
trench, one or more underdrains positioned across the trench, and a layer of filter media
SUBSTITUTE SHEET (RULE 26)
placed over the one or more underdrains. The underdrains include an upper structure for
filtering particulates from a fluid, a bottom plate connected to the upper structure that
includes an opening for draining the fluid into the trench, and at least one flow control vane
positioned between the upper structure and the bottom plate.
In one embodiment, the underdrain assembly may further comprise flume plate or
tubular member positioned in the trench for directing fluid flow. The flume plate or tubular
member may include smaller pipe extensions, which are then embedded into a floor of the
trench, and may allow for the inflow or outflow of fluid.
In one embodiment, in place of a plate over a trench, a large pipe with smaller
pipe extensions which are embedded into the floor of the basin can be used. The larger pipe
may be connected to piping external to the basin allowing for the inflow and outflow of fluid.
In one embodiment, an underdrain assembly is disclosed, comprising a trench and
an underdrain positioned across the trench. The underdrain can include an upper structure
for filtering particulates from a fluid, a bottom plate connected to the upper structure and
including an opening for draining the fluid into the trench. A water inlet may be provided for
introducing water from a chamber into an interior portion of the underdrain. An air inlet may
be provided for introducing air into the interior portion of the underdrain. The water inlet
may include a first end exposed to the chamber and a second end exposed to the interior
portion of the underdrain. The second end may have an end plate covering an upper portion
of the second end. The second end further may include an opening having an angular cut
that forms an angle with respect to a longitudinal axis of the water inlet.
SUBSTITUTE SHEET (RULE 26)
In one embodiment, an underdrain assembly is disclosed, comprising an
underdrain positioned on a base. The underdrain may include an upper structure for filtering
particulates from a fluid, a bottom plate connected to the upper structure, and a hold-down
mechanism for adjustably coupling the underdrain to the base. The hold-down mechanism
may include an anchor bolt coupled to the base, a hold-down bar coupled to one end of the
anchor bolt via a resilient member, and a leveling bolt having a first end in contact with the
hold-down bar and a second end in contact with the base. Rotating the leveling bolt may
adjust a position of the bottom plate with respect to the base.
In one embodiment, a manifold assembly for a plurality of underdrains,
comprising a plurality of underdrains, each of the plurality of underdrains comprising an end
connection, and a manifold having a plurality of receiving connections disposed along a
longitudinal length of the manifold, each of the plurality of receiving connections configured
to receive the end connection of a respective one of the plurality of underdrains.
In one embodiment, an underdrain using sets of perforations for air and water
control, can position the perforations strategically to optimize the operational installed angle
of the underdrain from a perfect horizontal line. The perforations can be placed in either or
the U-shaped channels or the flow control plate.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the invention can be
understood in detail, a more particular description of the invention, briefly summarized
above, may be had by reference to embodiments, some of which are illustrated in the
SUBSTITUTE SHEET (RULE 26)
appended drawings. It is to be noted, however, that the appended drawings illustrate only
typical embodiments of this invention and are therefore not to be considered limiting of its
scope, for the invention may admit to other equally effective embodiments.
Figure 1 is a perspective view of a typical underdrain assembly.
Figure 2 is a perspective view of an underdrain according to one embodiment of
the invention.
Figure 3 is a perspective view of an underdrain according to one embodiment of
the invention.
Figure 4A is a cutaway perspective view of an underdrain according to one
embodiment of the invention.
Figure 4B is a cutaway perspective view of an underdrain according to one
embodiment of the invention.
Figure 5 is a perspective view of a top cap according to one embodiment of the
invention.
Figure 6 is a perspective view of an underdrain according to one embodiment of
the invention.
Figure 7A is a perspective view of an underdrain according to one embodiment of
the invention.
Figure 7B is a perspective view of an underdrain according to one embodiment of
the invention;
SUBSTITUTE SHEET (RULE 26)
Figure 7C is a partial cutaway view of the underdrain of Figure 7B.
Figure 7D is an end view of the underdrain of Figure 7B.
Figure 7E is a cross-section view of the underdrain of Figure 7B, taken alone line
V-V of Figure 7D.
Figure 7F is a perspective view of an underdrain according to one embodiment of
the invention.
Figures 7G and 7H are partial cutaway views of the underdrain of Figure 7F.
Figure 71 is an end view of the underdrain of Figure 7F.
Figure 7J is a cross-section view of the underdrain of Figure 7F, taken alone line
W-W of Figure 71.
Figure 7K is a cross-section view of an underdrain according to one embodiment
of the invention.
Figure 8 is an illustration of a manifold assembly for a plurality of underdrains
according to one embodiment of the invention.
Figure 9 is a perspective view of a flume plate for an underdrain assembly
according to one embodiment of the invention.
Figure 10 is a side view of a further embodiment of an underdrain assembly
according to an embodiment of the invention;
SUBSTITUTE SHEET (RULE 26)
Figure 11 is a cross-section view of the underdrain assembly of Figure 10 taken
along line 11-11 of Figure 10.
Figure 12 is a detail view of a portion of the cross-section view of Figure 11.
Figure 13 is an isometric cutaway view of the underdrain assembly of Figure 10.
Figure 14 is a detail cutaway view of a portion of the view of Figure 13.
Figure 15 is a detail view of a water inlet line and plate portion of the underdrain
assembly of Figure 10.
Figure 16 is a partial cross-section view of an embodiment of a water inlet line of
the underdrain assembly of Figure 10.
Figure 17 is a partial cross-section view of another embodiment of a water inlet
line of the underdrain assembly of Figure 10.
Figure 18 is a perspective view of an embodiment of an underdrain according to
one embodiment of the invention, the underdrain positioned apart from a water chamber
assembly.
Figure 19 is a reverse perspective view of the underdrain of Figure 18.
Figure 20 is a cutaway perspective view of the underdrain of Figure 18 engaged
with the water chamber assembly.
Figure 21 is a cross-section view of the underdrain of Figure 18 engaged with the
water chamber assembly.
SUBSTITUTE SHEET (RULE 26)
Figures 22 and 23 are cross-section views of embodiments of air inlet lines for
use with the underdrain assembly of Figure 10.
Figure 24 is a perspective view of a portion of an underdrain assembly according
to an embodiment of the invention.
Figure 25 is a cross section of an underdrain assembly incorporation the portion
shown in Figure 24.
Figure 26 is a perspective view of an underdrain assembly according to an
embodiment of the invention.
Figure 27 is a partial cutaway view of the underdrain assembly of Figure 26.
Figure 28 is an end view of the underdrain assembly of Figure 26.
Figure 29 is a cross-section view of the underdrain assembly of Figure 26, taken
alone line Z-Z of Figure 28.
Figure 30 is a cross-section view of an underdrain assembly according to an
embodiment of the invention.
Figure 31 is a cross-section view of an underdrain assembly according to an
embodiment of the invention.
Figure 32 is a side view of an improved hold-down mechanism for use with the
disclosed underdrain assembly.
Figure 33 is an isometric view of the hold-down mechanism of Figure 32.
SUBSTITUTE SHEET (RULE 26)
DETAILED DESCRIPTION
An underdrain assembly 5 is shown in Figure 1, according to one embodiment.
The underdrain assembly 5 includes a base 10 that is comprised of a compact fill, such as
concrete, which is placed in a designated underdrain area. The base 10 includes a trench 15
that provides a centralized fluid flow collection area. A flume plate 20, which is typically a
steel plate, is inserted into the trench 15, and includes tubes 25 (shown in Figure 9) for
connecting to individual underdrains 30 located above the trench 15. A plurality of
underdrains 30 traverse the trench 15 and the flume plate 20. The underdrains 30 include a
bottom plate 35 which includes an opening for receiving the flume plate tube 25, and an
upper structure 40 that prevents filter media from entering into the underdrain, while
allowing fluid into the underdrain. A layer of filter media 45 is placed over the plurality of
underdrains 30. Water 50 is then allowed to move over and through the filter media 45,
through the underdrains 30, and through the trench 15. Alternatively, in the backwash
process, water may be pushed through the trench 15, through the flume plate tubes 25,
through the plurality of underdrains 30, and through the filter media 45.
Various embodiments of underdrains are described herein, and all may be used in
conjunction with the general underdrain assembly described above and shown in Figure 1.
Figure 2 is a perspective view of an underdrain 30 according to one embodiment of the
invention. The underdrain 30 includes a bottom plate 35, an upper structure 40 that prevents
filter media from entering into the underdrain, and one or more flow control vanes 60 that
extend at least partially within the underdrain 30.
The upper structure 40 includes a first filtration member 42 such as a wire mesh
screen, a plurality of screen elements, a perforated plate, or any other structure capable of
SUBSTITUTE SHEET (RULE 26)
filtering media known in the art. The first filtration member 42 allows water or liquid to
flow through the upper structure 40 while preventing media and other particulates from
moving through the upper structure 40. An exemplary first filtration member 42 includes a
Vee-Wire® screen. Optionally, the upper structure 40 further includes a support member 44,
which is coupled to the first filtration member 42. The support member 44 provides support
to the first filtration member 42, which in turn supports the weight of the fluid and filter
media sitting on top of the underdrain 30. The support member 44 includes holes or
perforations that allow the fluid or water to flow through the upper structure 40. The support
member 44 could be any structure that supports the weight of the fluid and includes holes. In
one embodiment, as shown in Figures 2 and 3, the support member 44 is a series of channel
rods with perforations or holes along the length of each channel rod. A channel rod in the
embodiment shown is a member that extends longitudinally along the first filtration member
42 and includes a u-shaped cross section. The channel rods may run adjacent to one another
wherein outer faces of sides of the channel rods interface, and wherein top portions of the
sides interface with the first filtration member 42. In one embodiment, the support member
44 is a perforated plate that is adjacent the first filtration member 42. The perforations of any
embodiment can be strategically placed to maximize the performance and tolerance of the air
water interface plenum.
The upper structure 40 may be semi-cylindrical, arced or curved, as shown in
Figures 2 and 3. The upper structure 40 may also be configured into a box-like structure
with the first filtration member 42 on at least a portion of a top side. The first filtration
member 42 could also be positioned on at least a portion of a side of the upper structure 40.
It is contemplated that the upper structure 40 may comprise a variety of configurations, so
SUBSTITUTE SHEET (RULE 26)
long as water or liquid is allowed to flow through the upper structure 40 and prevent media
and particulates from entering into the underdrain 30. The upper structure could be
constructed to house multiple instances of the lower control devices.
The upper structure 40 connects to the bottom plate 35 of the underdrain 30. The
bottom plate 35 of the underdrain 30 can be flat to allow fluid to uniformly move through the
underdrain. Formed or curved shapes that enhance structural or flow performance can also
be used. The bottom 35 includes at least one opening that leads to a trench 15, pipe or other
header assembly beneath the underdrain 30. This opening can also be located at the ends of
the underdrain for flow chambers with vertical cover plates. The opening allows water or
fluid to drain into the trench 15 so that the water or fluid may be collected in a centralized
location. The opening may also receive a flume tube from a flume plate 20 located in the
trench 15 to assist with drainage of the fluid.
The underdrain 30 also includes one or more control vanes 60 for controlling the
distribution of fluid flow within the underdrain 30. The control vanes 60 may restrict or
redirect fluid flow to approximate the change in resistance that would be achieved with a
variable geometry or step-down header without actually changing the geometry of the upper
structure 40 of the underdrain 30. The control vanes 60 may be of any geometry, such as a
rectangular plate, slotted plate, semi-circular plate or tubular configuration. The control
vanes 60 may also be of any width or length, and such width or length may vary from control
vane to control vane. The angle of the control vanes 60 relative to the centerline of the
underdrain 30 can also be altered as needed to improve flow distribution and control. As
shown in Figure 2, in one embodiment, one or more control vanes 60 may extend at least
partially from the upper structure 40 towards the bottom plate 35. In one embodiment, one
SUBSTITUTE SHEET (RULE 26)
or more control vanes 60 may extend at least partially from the bottom plate 35 toward the
upper structure 40. In one embodiment, one or more control vanes 60 may extend from the
upper structure 40 towards the bottom plate 35 while one or more control vanes 60 extend
from the bottom plate 35 towards the upper structure 40. In one embodiment, one or more
control vanes 60 can extend at least partially from a first side of the upper structure to a
second side of the upper structure, as shown in Figure 3.
One or more of the control vanes 60 may be positioned perpendicular to the
bottom plate 35, as shown in Figure 2. One or more of the control vanes 60 could be
positioned at one or more angles with respect to the bottom plate 35. One or more of the
control vanes 60 may also be positioned parallel to the bottom plate, as shown in Figure 3.
In some embodiments, the control vanes can include one or more pipes or tubes
of any appropriate cross-section that can be used in a similar fashion to the vertical or
horizontal control vanes 60 described herein.
In one embodiment, one or more control vanes 60 may be incrementally placed
along a longitudinal length of the underdrain 30, as shown in Figure 4A. The spacing
between each control vane 60 may vary or be equidistant from one another. Figure 4A
shows a cutaway perspective view of an underdrain 30, where two pairs of control vanes 60
are positioned perpendicular to the bottom plate 35 and parallel to one another. It will be
appreciated that one or more additional control vanes could be oriented, for example,
perpendicular to the bottom plate 35 and perpendicular to control vanes 60. In addition, the
control vanes 60 need not be positioned parallel or perpendicular to each other, and it is
SUBSTITUTE SHEET (RULE 26)
contemplated that some or all of the control vanes can be positioned at a variety of angles
with respect to each other. It is also contemplated that any number of control vanes 60 may
be positioned along the longitudinal length of the underdrain 30 at various positions to
provide a desired flow scheme and/or flow regime. For example, control vane 60 can be
positioned over the opening 65 in the bottom plate 35 of the underdrain 30, and may, in one
embodiment, extend into the trench 15 below the underdrain 30. The control vanes 60 may
be positioned and angled along the longitudinal length of the underdrain 30 to achieve a
desired fluid distribution along the underdrain 30.
Tubular geometry control vanes 60 can also be used. Figure 4B shows a set of
ring elements 60a and a tube element 60b disposed along the longitudinal length of the
underdrain 30 at various positions. These ring/tube elements 60a, 60b can be positioned as
desired to control the flow passing through the underdrain 30. Figure 4B shows a non-
limiting exemplary arrangement of a plurality of ring elements 60a and a tube element 60b
along the length of the underdrain 30. As can be seen, the sizes of the ring elements 60a can
be varied, as desired. In some embodiments, some or all of the ring elements 60a are
concentrically arranged, though this is not necessary. Likewise, the use, placement and
sizing of the tube element 60b (or elements) can also be varied to obtain a desired flow
scheme.
In one embodiment, the underdrain 30 further comprises a top cap 70 for
placement within the opening 65 in the bottom plate 35 of the underdrain 30. The top cap 70
may receive the flume tube 25 of a flume plate 20, such that fluid may flow into the top cap
70, out through the flume tube 25 and then into the trench 15. One embodiment of the top
cap 70 is illustrated in Figure 5. The top cap 70 may extend at least partially within or may
SUBSTITUTE SHEET (RULE 26)
be fully disposed within the underdrain 30. The top cap 70 is generally hollow with an outer
wall 71 and an inner wall 73. While the embodiment of the top cap 70 in Figure 5 is shown
as being cylindrical, the top cap 70 could include alternate configurations, such as a box-like
configuration. The top cap 70 includes one or more top cap openings 72 positioned along a
side of the top cap 70 and extending from the outer wall 71 to the inner wall 73. The top cap
openings 72 allow fluid to flow from the interior of the underdrain 30 into the top cap 70,
and move through the opening 65 and into the trench 15 below the underdrain 30. The top
cap openings 72 serve to provide a restriction for the fluid moving through the length of the
underdrain 30. Optionally, the top cap 70 may further include one or more top cap control
vanes 75 positioned within the top cap 70. The top cap control vanes 75 may extend from
one side of the inner wall to a second side of the inner wall, or from a top portion of the top
cap 70, and the top cap control vanes 75 may be positioned at any angle relative to the
bottom plate 35. The top cap control vanes 75 may extend above or below the top cap 70.
The top cap control vanes 75 further provide direction to the fluid flowing through the top
cap and also help restrict fluid flow in certain configurations.
Figure 6 is a perspective view of an underdrain 130 according to one
embodiment of the invention. The underdrain 130 includes an upper structure 140 and a
bottom plate 135, which are similar to those already described. The upper structure 140
includes a first filtration member 142, which allows water or liquid to flow through the upper
structure 140 while preventing media and other particulates from moving through the upper
structure 140. The upper structure 140 may optionally include a second filtration member
144, which in one embodiment, is a perforated plate. The second filtration member 144 may
be coupled to the first filtration member 142 so as to support the first filtration member, or
SUBSTITUTE SHEET (RULE 26)
may be positioned a distance away from the first filtration member 142, as shown in Figure
6. The second filtration member 144 includes perforations or holes that allow fluid or water
to move through the upper structure 140. When the second filtration member 144 is
positioned away from the first filtration member 142, as shown in Figure 6, the second
filtration member 144 effectively provides a restriction within the underdrain 130. The
second filtration member 144 may optionally include one or more formations 146 as shown
in Figure 7A, which may also provide a restriction for fluid flow through the underdrain
130, or may provide direction to the fluid flow. The configurations may also allow control
and separation of different types or phases of fluid flow, such as mixed air and water flows.
The formations 146 may include cross-sectional shapes in an s-shape pattern, a concave or
convex pattern, a z-shape pattern, a w-shaped patter, a v-shaped pattern, or any other pattern
known in the art. In one embodiment, the underdrain 130 includes control vanes 60 which
may be positioned between the first filtration member 142 and the second filtration member
144, or between the second filtration member 144 and the bottom plate 135. It is
contemplated that the control vanes 60 could be configured in a variety of ways as previously
discussed in order to distribute the fluid flow within the underdrain. The filtration member
144 can also be configured with a variable geometry to enhance the flow distribution, as
shown in Figures 7B-7J. These arrangements illustrate exemplary configurations that can
improve flow control, and can create a space for an air plenum to be developed in a more
contained space. These options illustrate geometries with both an open bottom plenum
(Figures 7B-7E) and a closed bottom plenum (Figures 7F-7J).
For example, Figures 7B-71 show an embodiment of an underdrain 130 with a
plenum open to the interior of the underdrain 145 The underdrain 130 of this embodiment
SUBSTITUTE SHEET (RULE 26)
includes a first filtration member 142 and a spaced-apart second filtration member 144
formed as a multiply-trapezoidal shaped perforated plate. The second filtration member 144
thus provides the open bottom plenum 145 with a lower trapezoidal portion 145a and an
upper trapezoidal portion 145b (see Figure 7D). The upper trapezoidal portion 145b is in
direct communication with an air inlet line 102. The air inlet line 102 may be coupled to a
source of compressed or pressurized air (not shown) to provide a desired air plenum in an
upper portion of the underdrain 130.
Figures 7F-7J show an embodiment of an underdrain 130 with a closed bottom
plenum. The underdrain 130 of this embodiment includes a first filtration member 142 and a
spaced-apart second filtration member 144. The second filtration member 144 is again
formed as a multiply-trapezoidal shaped perforated plate. In this embodiment, however, the
lower trapezoidal portion 145a and the upper trapezoidal portion 145b of the bottom plenum
145 are separated by a plate 144a (best seen in Figures 7F and 71), thus separating the upper
plenum portion from the lower plenum portion. The upper trapezoidal portion 145b is in
direct communication with the air inlet line 102. The air inlet line 102 may be coupled to a
source of compressed or pressurized air (not shown) to provide a desired air plenum in an
upper portion of the underdrain 130.
Figure 7K illustrates an embodiment of an underdrain 130 that employs multiple
second filtration member 144. In this embodiment, a pair of second filtration members 144
are positioned side-by-side on the bottom plate 135. It will be appreciated, however, that
greater numbers of second filtration members 144 can be used, as desired. It will also be
appreciated that this multiple second filtration member 144 arrangement can be implemented
in any or all of the embodiments described in relation of Figures 7A-7J.
SUBSTITUTE SHEET (RULE 26)
As will be appreciated, the embodiments of Figures 7A-K employ a secondary
screening surface to distance the filter media from the air release, providing better
distribution and less damage to the media.
Figure 8 is an illustration of a manifold assembly for a plurality of underdrains
according to one embodiment of the invention. In one embodiment, each underdrain 30
includes an end connection 82 that connects to a manifold 80. The end connection 82
includes formations that may be accepted by a reciprocal receiving connection 84 included
on the manifold 80. The manifold 80 provides one or more receiving connections 84 along a
longitudinal length, wherein one or more underdrains 30 may connect. The manifold 80 may
also provide the one or more receiving connections 84 on opposing sides of the manifold 80.
For example, one underdrain 30 may connect to the manifold 80 from one side, and a second
underdrain 30 may connect to the manifold 80 directly opposite of the other underdrain 30.
The manifold 80 allows underdrains 30 to be accurately positioned relative to one another.
Furthermore, the manifold 80 allows for easy installation of multiple underdrains 30 installed
in series to obtain a desired length. It is contemplated that each underdrain 30 could be
manufactured to a variety of standard lengths, each with the end connection 82 for
connection to a manifold or an end cap. Depending on the design needs and underdrain
length of a particular facility, an underdrain assembly could be easily and quickly assembled
by joining multiple underdrains 30 via a manifold connection.
In one embodiment, the manifold receiving connection 84 includes at least one
seal to prevent fluids from leaking out of the underdrain assembly and a locking assembly to
couple the underdrain 30 to the manifold. In one embodiment, the receiving connection 84
of the manifold 80 and the end connection 82 of the underdrain 30 may include a QuicklocTM
SUBSTITUTE SHEET (RULE 26)
connection. A receiving connection 84 and end connection 82 could be the connections,
such as reference numbers 10, 14, for example, described in U.S. Patent No. 8,516,678,
entitled "Push Lock Pipe Connection System," which is herein incorporated by reference in
its entirety.
It is also contemplated that instead of the manifold 80 receiving the underdrains
, that the underdrains 30 could receive the manifold. For example, the flume tubes 25 of
the flume plate 20 may extend into the manifold 80 that connects one or more underdrains 30
together. In either configuration, both the manifold 80 and the underdrains 30 include
reciprocal formations that lock together and form a seal.
Figure 9 is a perspective view of a flume plate 20 for an underdrain assembly
according to one embodiment of the invention. The flume plate 20 is formed to fit within the
trench 15 of an underdrain assembly. The flume plate 20 includes a top portion 24 and two
side portions 26. The top portion 24 and two side portions 26 may consist of steel, but it is
also contemplated that it could consist of other materials such as a polypropylene or other
rigid material. The top portion 24 is substantially flat so that the bottom plate 35 of an
underdrain may be adequately supported by the flume plate 20, and the flume plate includes
one or more flume tubes 25 positioned along its longitudinal length. The flume tubes 25 are
positioned within openings 65 in the bottom plates 35 of the underdrains 30. The flume plate
further includes one or more lock-in tabs 22 positioned on the side portions 26 of the
flume plate 20. The lock-in tabs 22 are received by reciprocal slots in the trench 15 so that
the flume plate 20 may not move from its position within the trench 15. The flume plate 20
may also include a plurality of anchors 27 coupled to the two side portions 26 of the flume
plate 20. The plurality of anchors 27 extend upward and help position the underdrains 30,
SUBSTITUTE SHEET (RULE 26)
which generally run perpendicular to the trench 15 and flume plate 20, on the flume plate 20.
Furthermore, the anchors 27 may optionally be coupled to the underdrains 30 to ensure the
position of the flume plate 20 relative to the underdrains 30 remain constant. In one
embodiment, the flume tubes 25 of the flume plate 20 extend into the manifold 80 that
connects one or more underdrains 30 together and the anchors 27 are coupled to the manifold
80. In one embodiment, a tubular member or other connecting structure may be used in
place of the flume plate 20 to direct fluid flow through the trench 15. The tubular member
may also include smaller pipe extensions, which are then embedded into a floor of the trench,
and may allow for the inflow or outflow of fluid.
In some embodiments the flume plate 20 may include one or more stiffeners 86
positioned on the upper and/or lower surface thereof to enable the thickness of the flume
plate to be reduced. In the illustrated embodiment a pair of rectangular stiffeners 86 are
provided on the lower surface of the flume plate 20. By adjusting the size, shape and/or
position of these stiffeners 86 on the flume plate 20, fluid distribution may be adjusted as
desired. For example, in some embodiments the stiffeners 86 may be arranged adjacent to
each other to form a "V" shape that can be used to adjust fluid distribution. It will be
appreciated that the stiffeners 86 can be formed from the same material as the flume plate 20,
or they may be formed from a different material.
Figures 10-17 show an embodiment of the disclosed underdrain 30 in which a
water inlet line 88 is provided at a longitudinal end 90 of the underdrain. The water inlet line
88 passes through, and is sealed to, a plate 92 via an elastomeric seal 94 such as a rubber
gasket. Thus, on one side of the plate 92 the water inlet line 88 is exposed to a water
chamber 96 to enable water from the water chamber to flow through the water inlet line 88
SUBSTITUTE SHEET (RULE 26)
into an interior portion 98 of the underdrain 30. Air may be introduced into an air plenum
portion 100 of the underdrain 30 via an air inlet line 102. In the illustrated embodiment, the
air inlet line 102 is disposed through the top of the underdrain 30, but this is not critical and
in some embodiments the air inlet line 102 may be positioned so as to introduce air
horizontally into the air plenum portion 100. The air inlet line 102 may be coupled to an
appropriate source of compressed or pressurized air (not shown) so as to force air through the
air inlet line into the interior portion 98 of the underdrain 30. In some embodiments the air
inlet line 102 may be coupled to an air header that itself is disposed on top of the underdrain
and acts as a hold-down bar for the underdrain. In some embodiments, the air inlet line
may be coupled to an internal air pipe with perforations or other flow control devices to
distribute air along the length of the underdrain assembly. This internal air header can be
used independently, or in addition to a secondary distribution layer of channel rod or
perforated plate.
As can be seen best in Figure 12, an air/water interface 104 exists within the
underdrain 30, with the air plenum portion 100 positioned above a water filled portion 106.
As will be appreciated, it is desirable to prevent the air from the air plenum portion from
flowing back through the water inlet line 88 into the water chamber 96. Thus, the water inlet
line 88 may have an end plate 108 disposed at a first end 110 thereof. The end plate 108 may
block off an upper portion of an opening 112 in the water inlet line 88. In some
embodiments, the end plate 108 may be positioned so that a top end 108a is disposed in the
air plenum portion 100 while a bottom end 108b is disposed in the water filled portion 106.
Thus arranged, the opening 112 in the water inlet line 88 is disposed entirely within the water
SUBSTITUTE SHEET (RULE 26)
filled portion of the underdrain 30, thereby preventing air from the air plenum portion 100
from escaping into the chamber portion 96 via the water inlet line.
In the illustrated embodiment, the opening 112 in the water inlet line 88 is formed
by an angular cut 114 made in the water inlet line 88 adjacent to the first end 110, and the
end plate 108 is oriented substantially perpendicular with respect to a longitudinal axis A-A
of the water inlet line 88. In some embodiments the angular cut forms an angle a with
respect to the longitudinal axis of the water inlet line, which in the illustrated embodiment is
parallel to the bottom plate 35 of the underdrain 30. The angular cut can be oriented with
either a forward or a reverse angle as required to achieve the desired effect of isolating the
gas phase (air) and liquid phase (water) flows. Other embodiments can include openings in
the side of the inlet pipe that achieve the same effect. Thus arranged, the opening 112 in the
second end forms a plane that is non-parallel to the longitudinal axis of the water inlet line.
The size and orientation of the end plate 108 can be configured so that the opening 112 has
the same or more cross-sectional area as a traditional open-ended pipe.
In some embodiments, the end plate 108 can be oriented so as to be +/- 15-
degrees from an absolute vertical orientation with respect to the axis of the water inlet line
88. Such an arrangement is shown in Figure 16, in which the plane of the end plate 108 is
oriented at an oblique angle with respect to the longitudinal axis A-A of the water inlet line
88. In other embodiments, as shown in Figure 17, an end plate 108 is disposed at both ends
of the water inlet line 88 to further inhibit the ingress of air into the chamber 96. In this and
other embodiments, a weep hole 113 may be disposed in a top portion of the water inlet line
88 to allow any air that may be trapped between the end plates 108 to escape.
SUBSTITUTE SHEET (RULE 26)
Figures 18-21 show an alternative arrangement of an interface between the
underdrain 30 and the plate 92 that covers the water chamber 96 (see Figure 10). In this
embodiment, the water inlet line 88 is engaged with, and sealed to, the plate 92. The
longitudinal end 90 of the underdrain 30 includes an opening 91 for receiving the water inlet
line 88 therein. The opening 91 may have a seal 93 for sealing against an outer surface of the
water inlet line 88 and/or the plate 92. Figures 18 and 19 show the underdrain 30 positioned
adjacent to the plate 92 prior to engagement with the water inlet line 88. Figures 20 and 21
show the underdrain 30 fully engaged with the water inlet line 88.
The embodiment of Figure 21 also illustrates an alternative arrangement of the
air inlet line 102. In this embodiment, the air inlet line 102 is partially disposed within the
water inlet line 88, and has an inlet end 102d disposed on the chamber side of the plate 92
(out of the media basin). The outlet 103 of the air inlet 102 is disposed through an opening
in an upper surface of water inlet line 88 within the underdrain 30. In some embodiments the
outlet 103 is can direct air out of this upper surface of the water inlet line 88, or it could be
augmented by an additional connecting pipe that helps to facilitate the air transfer into the
underdrain 30.
Figures 22-29 show various alternative arrangements for enhancing the
introduction of air into the underdrain 30. In some instances, these arrangements may
improve and/or enable the distribution of air in cases in which a discrete air plenum is not
viable. Although these embodiments show an air inlet line 102 positioned at the top of the
underdrain 30, it will be appreciated that the air inlet line 102 can extend from any exterior
surface of the underdrain, including end connections as will be described.
SUBSTITUTE SHEET (RULE 26)
Figures 22 and 23 show arrangements of an air inlet line 102 that extends
vertically from the top of the underdrain 30 to allow air to be introduced into the air plenum
portion 100 of the underdrain. In the Figure 22 embodiment, the air inlet line 102 is a
vertically oriented tube that extends through the first filtration member 142. A distal end
102a of the air inlet line 102 may have an angled opening 103 to orient the flow of air in a
particular direction. In the Figure 23 embodiment, the air inlet line 102 may have a
vertically oriented portion 102b that extends into the air plenum portion 100, and a
horizontally oriented portion 102c disposed within the air plenum portion. As will be
appreciated this arrangement can provide a desired orientation to the air introduced through
the air inlet line 102.
Figures 24 and 25 show an embodiment in which a horizontally oriented air inlet
line 102 is provided through the longitudinal end 90 of the underdrain 30. As can be seen,
the air inlet line 102 of this embodiment is oriented parallel to the water inlet line 88, though
this orientation is not critical and other orientations may also be used. The air inlet line 102
is also elongated so that it extends a distance "d" along the interior of the underdrain 30 to
facilitate air distribution through the underdrain. The air inlet line 102 is shown as being
disposed above the second filtration member 144. In some embodiments the elongated air
inlet line 102 includes perforations. In the illustrated embodiment the second filtration
member 144 is oriented at an oblique angle [3 with respect to the base plate 135 such that it is
closer to the air inlet line 102 directly adjacent the longitudinal end 90 of the underdrain 30
and is progressively spaced apart from the air inlet line as it extends along the underdrain 30.
As shown, the second filtration member 144 is angled downward within the underdrain 30.
It will be appreciated that in addition to, or apart from, the angled arrangement of the second
SUBSTITUTE SHEET (RULE 26)
filtration member 144, the second filtration member 144 can also transition through different
shapes (e.g., W-shaped, V-shaped, S-shaped) along its length.
Figures 26-29 illustrate an embodiment of the underdrain 30 in which an internal
distribution pipe 105 is provided along the length of the underdrain in the air plenum portion
100. The internal distribution pipe 105 is thus positioned between the first filtration member
142 and the second filtration member 144. The internal distribution pipe 105 can be coupled
to the air inlet line 102 to receive air from a pressurized air source. In the illustrated
embodiment, the air inlet line 102 couples to the internal distribution pipe 105 near, but not
at, the longitudinal end 90 of the underdrain 30. The air inlet line 102 can be perforated
along all, or a portion of, its length. Although a single internal distribution pipe 105 is
shown, it will be appreciated that multiple such internal distribution pipes may be employed,
and may be oriented to reach any internal portion of the underdrain 30 desired. In addition,
the internal distribution pipe 105 or pipes can be coupled to multiple air inlet lines 102, as
desired.
Figures 30 and 31 show arrangements of the underdrain 30 in which perforations
in the channel rods 44 (see Figure 2) or the second filtration member 144 are strategically
placed such that differences in height along the length of the underdrain can be
accommodated. This may be important because the concrete base 10 upon which the
underdrain 30 sits may not always be perfectly level. For example, if positioned atop a non-
level base 10, the underdrain 30 may be oriented at an angle y with respect to horizontal. It
is thus desirable to leave a large space between the perforations that will be subject to water
and the perforations that will be subject to air so that the air/water interface 104 (see Figure
12) can be maintained at a maximum tip angle y.
SUBSTITUTE SHEET (RULE 26)
In the Figure 30 embodiment, the channel rods 44 positioned adjacent to the
upper portion of the underdrain have perforations 44a that will be exposed to the air plenum
in use. The channel rods 44 positioned adjacent to the bottom plate 35 have perforations 44b
that will be exposed to the water filled portion 106. These perforations 44a, 44b may be
separated by a distance "PD" that will enable a desired air/water interface 104 to be
maintained even when the underdrain is oriented at a maximum tip angle y. In the Figure
31 embodiments, perforations are provided in the second filtration member 144. Upper
perforations 144a may be provided in the second filtration member 144 where it is adjacent
to an upper portion of the underdrain 30. One or more sets of lower perforations 144b may
be provided adjacent to the bottom plate 35. The upper and lower perforation groups (144a,
144b) may be separated by a distance "PD" that will enable a desired air/water interface 104
to be maintained even when the underdrain is oriented at a maximum tip angle y. An
advantage of the arrangement shown in Figures 30 and 31 is that it may enable the
underdrain 30 to be used without the need for additional external adjustment assemblies
which are currently employed to level the underdrain when it is positioned atop a non-level
base 10.
Figures 32 and 33 illustrate a hold-down mechanism 115 for the disclosed
underdrains 30. The hold-down mechanism 115 can perform a variety of functions,
including maintaining the underdrains 30 in a level state, and holding them in place during
normal and backwash operations. The hold-down mechanism 115 can also include a shock
absorbing feature 117 for providing a smooth distribution of forces during backwash
operations and for reducing the effects of water hammer in the system. The added flexibility
SUBSTITUTE SHEET (RULE 26)
afforded by the shock absorbing feature 117 can extend the fatigue life of the hold-down
mechanism 115 as well as one or more portions of the underdrains 30.
In the illustrated embodiment the hold-down mechanism 115 can include an
anchor bolt 118, a hold-down bar 120 and first and second leveling bolts 122, 124. The
anchor bolt 118 may have a first end 118a coupled to the base 10 (see Figure 1), and a
second end 118b that protrudes through an opening 126 in the hold-down bar 120 and
engages one or more threaded nuts 128. A bottom-most of the threaded nuts 128 may bear
against a washer 130, which itself engages a top surface of a resilient member 132. The
resilient member 132 may be configured to hold the washer 130 at predetermined offset
distance "d" from the hold-down bar 120.
The first and second leveling bolts 122, 124 may have first ends 122a, 124a that
abut the base 10 and are received by first and second leveling nuts 131, 133 that are fixed, by
welding, brazing or other appropriate technique, to the bottom plate 35 of the underdrain 30.
Respective and second ends 122b, 124b of the first and second leveling bolts 122, 124 have
bolt heads 134, 136 that abut an underside surface 138 of the hold-down bar 120.
As noted, the first end 118a of the anchor bolt 118 may be fixed to the base 10.
By rotating the first and second leveling bolts 122, 124, the underdrain 30 can be raised or
lowered with respect to the base 10, adjusting an offset distance "OD" between the bottom
plate 35 and the base 10. The second ends 122b, 124b thus act as footings for the underdrain
The resilient member 132 imposes a downward force against the bolt heads 134,
136, allowing the hold-down bar 120 to gently "ride" up and down depending upon the
SUBSTITUTE SHEET (RULE 26)
forces applied to the underdrain 30. In this way, a rigid connection between the anchor bolt
118 (and base 10) and the underdrain 30 is avoided, which as will be appreciated will result
in less shock to the hold-down mechanism 115 and the underdrains 30 during operation.
In the illustrated embodiment (Figure 33) the resilient member 132 is a leaf
spring having a top base portion 148 and oppositely disposed first and second angled legs
150, 152. The first and second angled legs 150, 152 have respective first and second clips
154, 156 disposed at the distal ends of the first and second angled legs. The first and second
clips 154, 156 each has a pair of ears 158, 160 that wrap around a portion of the hold-down
bar 120 to provisionally the position of the leaf spring and the anchor bolt 118 with respect to
the hold-down bar. The anchor bolt 118 is received through an opening (not shown) in the
top base portion 148, and a washer - sandwiched between the lower-most of the one or more
threaded nuts 128 — bears against the top base portion. Upward motion of the hold-down bar
120 with respect to the anchor bolt 118 causes the leaf spring to compress, while downward
motion of the hold-down bar with respect to the anchor bolt 118 causes the leaf spring to
elongate. Both conditions result in the resilient leaf spring urging the hold-down bar 120
back to a neutral position with respect to the anchor bolt 118.
Although the illustrated embodiment shows the resilient member 132 as being a
leaf spring, it will be appreciated that other resilient elements can be used instead (or in
addition), including resilient (e.g., elastomeric) gaskets and/or o-rings, Belleville washers,
and the like, to achieve a desired effect of dampening vibrations expected during operation of
the device. In addition, although the illustrated embodiment shows the resilient member 132
positioned on top of the hold-down bar 120, it will be appreciated that the resilient member
could instead be provided below the hold-down bar to achieve a desired dampening effect.
SUBSTITUTE SHEET (RULE 26)
It will be appreciated that although the illustrated embodiments show the
underdrain 30, 130 as having a circular cross section, some or all of the aspects of the
disclosed flow control devices and other enhancements could be applied equally to an
underdrain having semi-circular, elliptical, trapezoidal, rectangular or other cross section
known in the art.
While the foregoing is directed to embodiments of the invention, other and further
embodiments of the invention may be devised without departing from the basic scope
thereof, and the scope thereof is determined by the claims that follow.
SUBSTITUTE SHEET (RULE 26)
Claims (14)
1. An underdrain assembly, comprising: a trench, enclosed header or flume; and an underdrain positioned across the trench, the underdrain including: an upper structure for filtering particulates from a fluid; a water inlet for introducing water from a chamber or header into an interior portion of the underdrain or extracting water from the underdrain into the chamber or header; and an air inlet for introducing air into the interior portion of the underdrain wherein the water inlet comprises a first end exposed to the chamber and a second end exposed to the interior portion of the underdrain, the second end having an end plate covering an upper portion of the second end, the second end further comprising an opening having an angular cut that forms an angle with respect to a longitudinal axis of the water inlet.
2. The underdrain assembly of claim 1, wherein the end plate is oriented perpendicular to the longitudinal axis of the water inlet.
3. The underdrain assembly of claim 1, wherein the end plate is oriented at an angle that is +/- 90-degrees from perpendicular with respect to the longitudinal axis of the water inlet.
4. The underdrain assembly of any one of claims 1 to 3, comprising a second end plate disposed at the first end of the water inlet, the second end plate covering an upper portion of the second end.
5. The underdrain assembly of any one of claims 1 to 4, wherein an opening in the first end of the water inlet forms a plane that is non-parallel to the longitudinal axis of the water inlet.
6. The underdrain assembly of any one of claims 1 to 5, wherein the water inlet includes a weep hole formed in an upper portion of the water inlet to allow trapped air to escape from the water inlet.
7. The underdrain assembly of any one of claims 1 to 6, wherein the end plate is configured to be positioned at an air/water interface region in the interior portion of the underdrain assembly.
8. The underdrain assembly of any one of claims 1 to 7, wherein the opening in the second end of the water inlet forms a plane that is non-parallel to the longitudinal axis of the water inlet.
9. The underdrain assembly of any one of claims 1 to 8, wherein the air inlet is coupled to a source of compressed or pressurized air.
10. The underdrain assembly of any one of claims 1 to 9, wherein the air inlet is coupled to a source of compressed or pressurized air and extends the length of the underdrain assembly.
11. The underdrain assembly of claim 10, wherein the air inlet is disposed on an external surface of the underdrain assembly to allow connection to the source of compressed or pressurized air.
12. The underdrain assembly of claim 11, wherein the external surface is selected from the list consisting of top, end, side and bottom.
13. The underdrain assembly of any one of claims 1 to 12, wherein the air inlet can include additional devices to redirect flow down the length of the underdrain assembly.
14. The underdrain assembly of any one of claims 1 to 13, wherein the water inlet is sealed to a plate separating the underdrain assembly from the chamber.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201361765375P | 2013-02-15 | 2013-02-15 | |
US61/765,375 | 2013-02-15 | ||
NZ712179A NZ712179A (en) | 2013-02-15 | 2014-02-14 | Underdrain assembly |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ741663A NZ741663A (en) | 2020-03-27 |
NZ741663B2 true NZ741663B2 (en) | 2021-04-28 |
Family
ID=
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