Note: Descriptions are shown in the official language in which they were submitted.
CA 02458282 2004-03-04
TNTEGRATED DIVERTER AND WASTE CO~2~lINUTOR
H~ACKGROUND OF TI3E INVENT I ON
1. Cross Reference to Other Patents.
This invention is related to commonly assigned U.S. Patents
5,478,020, 5,505, 388 and 5,593,100.
2. Prior .Art
This invention relates to the combination of a solid waste
coznminuting apparatus and a screening system to divert solid matter
contained in an influent stream to the comminutor for .purposes of
size reduction. Prior screening/ comminuting systems are disclosed
in U.S. Patent 5,505,388. ~s- .set
forth in the '388 patent, as is well known in waste water
treatment, there are many environments where large volumes of
liquid require initial processing for purposes of coarse screening
so that large solid objects are diverted in the influent stream and
their size reduced by a grinding unit. The material, now of a
reduced size, is either removed at the point of reduction cr
re-introduced into the stream for further processing downstream.
This invention is an improvement~over the technology disclosed
in U.S. Patent 5,505,388. The '388 patent and the coaunercial
technology steauning from it represented a significant improvement
over prior vertically oriented bar screens which .were typically
used in waste water treatment plants for the purposes of removing
solids from a liquid flow. Those prior devices thus utilized rakes,
1
S
CA 02458282 2004-03-04
or the like which moved at an angle generally vertical, and
therefore perpendicular to the fluid flow in a vertical plane. This
resulted i.n undesirable hydrostatic effects in addition to a
propensity of such systems to clog, when fine screens are used, and
require a considerable amount of power for purposes of lifting
solid materials.
The '388 technology departed from this prior technique by
integrating into a common housing a diverter unit, for example a
rotating drum placed directly in the fluid flow with an adjacent
comminutor disposed in that flow to receive solids that were
diverted by the drum. The drum and the comminutor were commonly
powered. Consequently, the drum allowed fluid to pass through it
but at the same time presented a barrier for solid matter that
could not pass through the screening elements. The solid matter was
then diverted to one side of the fluid flow where it was then
ground into smaller particles and then those particles remain in
the stream for substantive downstream processing.
A variant of this basic technique of diverting solids in the
stream used double drums, one placed on each side of the
comminutor. This system is particular effective for wide flow
channels. By this technique, flow rates are maintained in the
stream but, solids are efficiently diverted toward the comminutor
for size reduction.
These systems have been commercially successful and as a
result of that success a number of areas of further improvement
2
CA 02458282 2004-03-04
have been identified. One area of improvement is in the drive
system for the comminutor and the drum. For example it is desirable
to incorporate the capability to tighten the stack of the
comminutor from the top as disclosed in U.S. Patent 5,478,020.
However since the screen assembly and the drive train are located
in the top end housing of integrated systems, top stack tightening
was not considered to be feasible.- Additionally in prior systems
rags could wrap around the lowest cutters and combined with grit
would degrade the casting material of the end housing. The result
was an expensive repair for the entire end housing.
Another area of improvement deals with the diverter and the
manner of support. The diverter, typically a drum, employed a side
rail on one side to improve flow characteristics and provide
structural support. To maintain overall rigidity of the system
additional components were required. This was a face plate attached
to top and bottom end housings to complete the frame with the side
rail. As a part of the frame prior designs used a face plate bolted
to the front of the device which served as structure extending the
width of the unit. This framing served to mount the overall frame
in a sewage channel when it was lowered and secured to a fixed
metal structure fastened to opposing walls of the channel. As can
be appreciated the face plate is a fixed dimension and mounting was
thus a function of channel width and the need to size the framework
to match.
Prior designs used a drum having a center shaft running
3
CA 02458282 2004-03-04
vertically the length of the drum. Small particles of rags and
other solids in the waste stream entering the interior of the drum
through screen apertures could wrap on the center shaft. Eventually
this buildup on the shaft would increase, enlarging in diameter and
caused an internal blockage. In turn a loss of flow through the
screen could result decreasing the efficiency of the screen.
Previous drum configurations used intermediate sprockets to
support the drum in a spatial arrangement along the central shaft
of the drum. Any portion of the screen between the sprockets was
unsupported except by the interconnection of the screen material
itself. This lack of support caused an hour glass effect between
the interface of the screen and the grinder. That is the outer
surface of the screen parallel to the axis of rotation would not be
in alignment causing gaps at the interface with the grinder.
Prior screening systems, for example those described in U.S.
Patent 4,919,346 used an internal deflector. This was possible
since the diverter was a screen, elongated with two interior
shafts . However, in the context of a rotating drum of the type in
the '388 patent such internal deflectors could not be incorporated
because the diverter was configured around sprockets containing
spokes.
SU~.RY OF THE INVENTION
Given the desire to improve the state of the art in the
screening and size reduction of solids in a fluid stream it is an
object of this invention to provide an integrated diverter and
4
CA 02458282 2004-03-04
grinder unit that has improved construction yet is easily
maintained.
It is yet another object of this invention to provide an
integrator diverter and grinder unit which has improved flow
characteristics using an internal deflector and side rails.
A further object of this invention is to provide a combined
diverter and grinder unit which has an improved screen
configuration that improves flow yet efficiently diverts solids to
the grinder.
These and other objects of this invention are accomplished by
means of an integrated system which utilizes a common mounting
structure for both the diverter and the grinding unit including an
integral vertical guide rail to facilitate mounting in the waste
water channel.
A wear plate is provided for the bottom end housing that bolts
on and protects the main end housing casting.
Preferably the diverter is in the form of a cylinder that is
shaftless within the cavity of the drum. Vertical ribs of the drum
which attach top intermediate and bottom sprockets extend inwardly
towards the interior of the drum. The ribs form and assist in the
removal of solids from the face of the drum.
In one preferred embodiment of the drum a continuous coil is
used in an helical or ~~slinky" type of configuration. This type of
drum, also a centerless shaft configuration, permits a higher
percentage of open area to enhance flow capabilities through the
CA 02458282 2004-03-04
device.
The drum is positioned so that its outer circumferential
surface is substantially tangential to a circle drawn to
circumscribe the elements of an adjacent cutter blade assembly.
The screen may be placed at either the right or the left of the
grinder unit. Alternatively, a pair of diverters can be employed
with the grinder unit positioned in the center, with both diverters
driven by a common drive source off the grinding unit. The drive
system utilizes stub shafts at top and bottom to facilitate removal
of the drum without disassembly of the unit.
This invention will be described in greater detail by
referring to the drawings and the description of the preferred
embodiments which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a cutaway perspective view of a first preferred
embodiment of this invention;
Fig. 2 is a back view illustrating the essential components of
the first preferred embodiment and the provision for top stack
tightening;
Fig. 3 is a top view illustrating the alignment of the grinder
unit with the diverter element of the first preferred embodiment
and the provisions for side rail flow control
Fig. 4 is a cutaway perspective view of a second preferred
embodiment of this invention utilizing a pair of rotating diverter
elements with a grinder unit centered there between:
6
CA 02458282 2004-03-04
Fig. 5 is a top view of the second preferred embodiment of
this invention illustrating flow control;
Fig. 6 is a sectional view illustrating the seal configuration
of this invention; and
Fig. 7 is a side view of a diverter unit in accordance with
this invention using a helical coil drum.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figs. 1, 2, and 3 a first preferred
embodiment of this invention will be described. This first
preferred embodiment comprises three major sub-components which are
integrated together to form a unitary system. These are the frame
element 100, the grinder element 200 and a single rotating screen
30-0. Referring now to Figs_ 1 and 2, the frame comprises a top
cover 19 and a bottom cover 13. An end housing 17 is associated
with the top cover and an end housing 18 is associated with the
bottom cover 13. The top cover 19 is affixed to the end housing 17
by means of a series of fasteners 25. Similarly, the bottom cover
13 is coupled to the end housing by means of appropriate fixing
elements, not illustrated. Lifting rings 26 are provided to raise
and lower the unit into position.
A side rail 16 on the grinder side and the side rail SO for
the drum each have vertical grooves 117, 118 running top to bottom
of each end housing (See Fig. 3). These form integral alignment
paths to permit the unit to be lowered or raised. The grooves are
fashioned to permit a compatible flange from a fixed structural
7
CA 02458282 2004-03-04
element mounted to the wall of the sewage channel to serve as a
guide.
A wear plate 20 (See Fig. 3) bolts on to the bottom end
housing 18. This wear plate is replaceable and protects the bottom
end housing casting 18. In prior systems grit and the like would
degrade the casting material forming the lower end housing casting.
Also, debris tended to accumulate around the lowest cutters in the
stack requiring occasional replacement of the bottom end housing.
By the use of a sacrificial plate this problem is eliminated.
In accordance with this invention an access port 27 is
provided in the top housing to provide access to the top nut 28. A
cover plate, not illustrated, is removable. As illustrated in
Figures 1 and 2 a gear train 29, 30 transmits the output of the
power source 43 to the grinder unit 200. In this invention, grinder
shafts 32, 34 permit top shaft tightening. This is accomplished by
means of locking the nut 28 of shaft 34 through access port 27 and
applying torque to the screw 525 (Fig. l) of shaft 32. This
eliminates the need to dissemble components or remove the unit for
tightening at the bottom as was the past practice. It eliminates
the need to disassemble components or remove the unit for
tightening at the bottom as in the prior art.
The grinder unit comprises a dual shaft system comprising a
drive shaft 34 and a driven shaft 32. On the driven shaft '32
cutter elements 36 alternate with spacer elements 38. On the drive
shaft 34 cutter elements 40 alternate with spacers 42, as
8
CA 02458282 2004-03-04
illustrated in Fig. 2. The result is that at the overlapped point
between the two cutter assemblies the cutter elements on one shaft
interleave with the cutter elements on the other shaft because of
the staggered relationship between spacer elements on the two
shafts .
While the foregoing discusses rudimentary details of the
grinder element which will be disclosed in greater detail here,
reference is made to United States Patent 4,046,324 for a more
complete discussion of a suitable grinder system.
In accordance with this invention improved flow control is
established by the use of a number of flow guides and diverters.
These improve flow around both the grinder unit and its cutting
elements as well as the drum. The purpose is to maintain flow of
fluid through the system while at the same time diverting solids
for reduction and preventing accumulation of debris. These will now
be described with reference to Figures 1-3.
Positioned between the two end housings 17 and 18 is a side
rail 50 for drum 60. The side rail acts not only as a spacer
between the top and bottom end housings but also as a baffle to
guide solids toward the diverter and prevent them from passing
around the outside of the drum. This side rail 50 also supports
both the top and bottom housings 17~ and 18 since the drive and
driven cutter shafts 32, 34 are not centered front to back in ' the
frame.
Another side rail 70 is used in conjunction with the grinder
9
CA 02458282 2004-03-04
unit. This side rail is slotted and also runs top to bottom and
provides support on the grinder side of the frame. This side rail
promotes flow around the cutting elements on the stack mounted on
shaft 32.
Flow through the cutting unit is improved.by purposes of channeling
fluid direction in a manner generally parallel to the cutter
elements. This is accomplished by slotting the side rail to have a
series of parallel flow paths extending in a spaced but staggered
arrangement relative to the adjacent cutter stack on shaft 32.
A low flow solids diverter 80 is positioned as a part of the
bottom end housing 18_ This diverter is positioned on the
downstream side of the frame at the interface of the grinding unit
200 and the drum unit 300. The purpose of this diverter is to
prevent solids. that have exited the grinder unit from bypassing a
downstream device such as an auger attached to the frame.
The diverter 60 comprises a drum that is shaftless within the
interior of the drum. This ~is illustrated in Figure 1. Prior
systems employed a central shaft running vertically the length of
the drum. As a result debris such as small rags and the like would
enter the interior of the drum and wrap and accumulate around the
shaft. Over time they would build up and reduce flow through the
screen thereby reducing efficiency.
In accordance with this invention the diverter employsw a
. shaftless configuration. ht uses top and bottom hub sprockets 7~1
having radial spokes 72 coupled to an inner peripheral ring 74 of
CA 02458282 2004-03-04
the drum 60. An intermediate sprocket is also used. It will be
apparent that the spokes are aligned,with the flow path as opposed
to be placed perpendicular to it. The diverter itself has a grid
with openings and series .of screen segments 76. As illustrated in
Figure 3, the drum 60 rotates counterclockwise, toward the grinder
unit as indicated by the arrow A. The leading edge of the diverter
elements is tapered to facilitate diversion of solids toward the
grinder without having them adhere into an opening. Given this
tapering the screen tends to be self cleaning.
Additionally a series of vertically extending ribs 78 act as
internal deflectors. These ribs of the drum assembly attach to the
top bottom and. intermediate sprockets ~ 71 and extend inwardly
towards the interior of the diverter 60. ~Thile illustrated as
straight they may also be curved. Their purpose is to assist in the
removal of solids from the surface of the screen by hydraulic
action tending to force the material outward to the front surface
of the diverter. This action allows the solids to be picked up by a
cutter element of the grinder unit. As a result, unground solids
cannot pass between the diverter 60 and the grinder unit.
The diverter ~60 can be removed for servicing without complete
disassembly of the frame. The top and bottom sprockets 71 are
secured to the respective stub shafts 81, 82 by bolts 84. By
removal of these bolts the unit 60 may be separated from the drive
assembly for servicing.
The cutter assembly is journaled for rotation in the bottom
z1
CA 02458282 2004-03-04
1
_ l
end housing by means of a seal-bearing assembly 44 as illustrated
in Fig. 6. In this invention stack tightening,occurs at the top of
the stack. During initial assembly a snap ring fixes the shafts 32
and 34 into position'. The seal assembly 44 may be a separately
removable cartridge having, as a replaceable unit, bearings, stator
and rotating race assemblies together with associated internal
0-ring assemblies. This seal bearing assembly may be of the type
disclosed in U.S. patent 5,593,100y
It may also be a fixed seal and bearing assembly.
In accordance with this invention a groove 39 forms a tortuous
path within the cartridge itself. 'This path 39 extends between the
bearing cartridge 41 and the insert cartridge 43. This differs~from
prior configurations where the tortuous path was formed between the
housing and a compression disk.
As disclosed in the '100 patent, the bearing assembly has a
cartridge housing 92, a dynamic race 94 and a static race 96. A
bearing assembly 98. is an integral part of the structure. Further
details are set forth in the '100 patent.
At the upper end of the frame 100, the side rail 70 for the
grinder unit is fixed .into position by means of locking elements.
Shafts 32 and 34 are held relative to the top end housing I7 by
means of clamping elements and an upper seal assembly 72, 74. A
drive shaft 4 is coupled to a motor 43 by means of a~coupling 46.
The motor 43 is illustrated in Fig. 1 as an electric motor.
However, the motor may be hydraulic. Thus in this embodiment, as
12
CA 02458282 2004-03-04
in the case of this invention, the choice of motor drive for the
system is not significant.
The drive shaft 34 has mounted to it a pinion 35, which in
turn drives the gear 30 mounted on the driven shaft 32. The drive
shaft 34 also is used to drive the screen 60.
The rotating diverter 60 is mounted on a stub shaft 81. The
shaft is journaled for rotation by a bearing assembly 90 held in
place by a retaining- ring.
The diverter drum utilizes a gear drive employing a driven
shaft 80 having mounted thereon a gear 91. An intermediate gear is
employed so that for each rotation of the driven shaft 32 there is
corresponding rotation of the diverter 60. As appropriate, the
housings are gasketed by means of top gasket or bottom gasket to
provide the necessary resiliency and sealing between the housing
members.
While this embodiment employs a gear drive, it will be
appreciated that other drive mechanisms may be used such as
sprockets and chain, belts and the like. The relative rotational
speed of the grinder elements to that of the diverter is determined
by the diameters of the drive and driven elements. This is also
accomplished in the preferred embodiment by gearing arrangements,
differential sprocket geometries or other well known techniques to
create different rotational speeds between elements~,driven from a
common source. It will be appreciated that it is preferable for
the grinder to rotate at one speed and the diverter at another to
13
CA 02458282 2004-03-04
promote the effective transfer and grinding of debris. Also, to
that end the diameter of the diverter can be modified as a function
of channel size to increase flow characteristics of the system.
Referring now to Figs. 2 and 3, the relationship between the
diverter 300 and the cutting elements of the grinder unit 200 are
depicted. As illustrated in Fig. 3 the outer circumference of the
diverter 60 defines a circle of a drum. Likewise, the outer
circumferential points of the cutter elements of each of the
cutters 36 defines a circle. The tangent common to those two
circles is illustrated by the line T-T in Fig. 3. Consequently, in
mounting the diverter assembly 300, relative to the cutter assembly
200, this geometric orientation is satisfied by mounting those
elements on a frame element 100. The orientation is illustrated in
Fig. 3 such the grinder and the diverter have a generally side by
side orientation relative to the fluid stream. The position of the
low flow diverter with respect to the tangent line T-T is
illustrated in Figure 3.
Referring now to Figs . 4 and 5 a second preferred embodiment
of this invention is depicted. In the first preferred embodiment a
single rotating screen 'unit is illustrated. While illustrating a
"left hand model" in Fig. 2, that is, with the screen placed to the
left of the cutter assembly, it is obvious that the system could be
reversed having a "right handed model". The embodiment of Figs: 4
and 5 provides a pair of rotating diverter assemblies 300 and 400
together with a centrally disposed cutter unit 200. Figure 4
14
CA 02458282 2004-03-04
illustrates the components housed in a common frame 100. To the
extent like elements are depicted in this embodiment, the same
numbering is used as with the first preferred embodiment.
Figures 4 and 5 thus illustrate a symmetrical condition with
the cutter unit 200 positioned between diverters 300 and 400. The
diverters 300 and 400 are identical, driven off a centrally
disposed drive shaft having the gear drives as described with
respect to the first preferred embodiment. It is also noted that
the tangential alignment between cutter stack and a diverter which
exists with the single diverter and cutter embodiment of Figs.l, 2
and 3 is maintained in the dual .screen unit of Figs. 4 and 5. The
two tangential lines T-T and T'-T' are illustrated in Fig. 5.
By comparing the components forming the top and bottom, end
housings 17 and 18, as illustrated in Fig. 1, it can be appreciated
from Fig. 4 that those same units are employed by simply having the
unit completed as a second mirror image of that illustrated in Fig.
1. That is, the top housing 17 together with the top cover 19 is
replicated in Fig. 4 so that it provides the necessary mounting and
fixing points for the second diverter unit 400.
In both embodiments, the frame element 1-00 mounts directly
into the waste water channel. Preferably, the waste water channel
has concrete walls and the system is bolted into place. The
grinding unit of the first preferred embodiment has its rigidity
maintained by the use of the side rail 70 and the frame, especially
the top cover 19 and the top end housing 17 which, as illustrated
CA 02458282 2004-03-04
' ~ )
in Fig.2, mounts directly to the grinder unit. In the second
preferred embodiment, using a pair of diverter screens the side
rail for the grinder is not required. A pair of side rails 50, one
for each drum provides reinforcement_ Rigidity is also accomplished
by the inherent symmetry of the system., The entire system is
attached to the channel frame via groove members 117' and 118.
,Additional structural rigidity is provided by the input side guide
plates 51 and 450.
As illustrated in Figures 4 and 5 the drum assemblies 300 and
400 are identical. Both use the shaftless construction with hubs 71
.and 470 and radial spokes 72, 472. Internal diverters 78, 478 are
employed. In Fig. 5, "460" and "480" correspond to "60" and "81",
respectively.
As is apparent from the drive elements illustrated in Fig. 1,
the rotational direction of the diverter cylinder stub shaft 81 is
accomplished by means of a gear that is slaved to the drive shaft
34 by means of a gear assembly. Consequently, a reversal in the
direction of grinder rotation automatically reverses the direction
of cylinder rotation. This is done because the units rotate via a
common gear assembly: --
In the. case of the second preferred embodiment illustrated in
Figs. 4. and 5, the second diverter unit 400 is driven off a pinion
by means of a sprocket 436. This will permit the two screens 300
and 400 to rotate in opposite directions thus diverting solids into
the center of the grinding unit 200. That is, the direction of
rotation of screen 300 is the same as that of the driven shaft 32
16
CA 02458282 2004-03-04
while the direction of rotation of the screen 400 will be the same
as that of the drive shaft.
The diverter unit illustrated employs a segmented drum having
discrete openings. One modification of this structure is
illustrated in Fig. 7. This configuration is also centerless but
employs a continuous helical coil 500. This "slinky" type
configuration provides for increased open area. Additionally the
pitch of the helix may be varied to suit different flow
considerations such that the drum coil can be individually tailored
to specific dynamic conditions. The coil 500 is supported on four
vertical supports 502. Shafts 504 and 506 are used to mount the
diverter to the frame for rotation. Shaft 504 is splined or
otherwise formed to accept a gear. A top frame member 508 couples
the supports 502 to the shaft 504. Similarly, a frame 510 couples
the supports 502 to the bottom shaft 506.
While four vertical supports are illustrated it is apparent
that the number is not critical. Rather, so long as rigidity for
the coil is established the supports may be placed in a geometric
relationship. Each support 502 has a series of notches 503. The
coil is held in position by the notches at the proper spacing. The
coil is typically stainless steel having sufficient strength and
resiliency to mount on the supports 502 in tension. The diverter,
thus constructed, is an integral unit mountable or removable as a
whole.
A modification of either of the preferred embodiments can
17
CA 02458282 2004-03-04
employ an auger screen positioned immediately behind the grinder.
The auger screen may be positioned and be the type described and
illustrated in the '388 patent. It generally comprises an elongated
tapered tubular housing with the internal auger that is suitably
powered by a motor. Given this positioning of the auger, entrained
liquid from the grinder is returned to the flow path while the
coarse materials are lifted and removed via the chute for off-line
handling.
In addition to the modifications specifically delineated
herein, it is apparent that other modifications may be made to this
invention without departing from the scope thereof. For example,
while a dual shaft grinder unit is disclosed, this invention will
operate with a single shaft grinder unit. Also, the auger -screen
system can be employed with the single screen embodiment.
Additionally, the device can be constructed with or without
the stub shaft diverter. For example, Where issues of ease of
replacement are not a concern, the slinky type of diverter inay be
employed. Moreover, other components of this configuration, such
as the improved flow control permit construction of diverter units
employing the diverter drum of the '388 patent. Thus, while a
complete system has been disclosed with alternate type of
diverters, it will be appreciated that various other subassemblies
can be employed advantageously.
18
