Note: Descriptions are shown in the official language in which they were submitted.
CA 02592214 2007-06-26
SYSTEMS AND METHODS FOR CONVERTING ORGANIC WASTE MATERIALS
INTO USEFUL PRODUCTS
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
[]] The present invention relates generally to processing of waste materials,
and more
particularly to systems and processes for handling organic waste materials.
2. DESCRIPTION OF THE PRIOR ART
[2] The traditional method of waste handling has been landfilling, the process
of burying
waste in a landfill. However, landfilling can cause environmentally
unacceptable pollution,
discharges to the water and, as real estate values increase, is considered to
be an unattractive use
of land. Thus, current waste management strategies seek to limit the amount of
refuse directed to
landfills. Recycling and composting programs have become widely accepted for
both
commercial and residential waste to reduce the demands on landfills.
[3] An alternative to composting for non-recyclable waste are refuse-to-energy
plants where
material is burned to create energy. Refuse-to-energy plants first process the
waste by grinding
and then burning the ground material. Although efforts are made to separate
out hazardous
materials from the waste stream, these plants have had a history of emissions
and operational
problems related to contaminants. The residual ash created from this burning
has also, in some
cases, been found to be hazardous.
[41 Anaerobic digestion presents an altemative for handling organic waste
materials. The
primary objective of anaerobic digestion is the production of a mixture of
hydrocarbon gases
("biogas"), which may be utilized as an energy source to generate electricity
and/or heat. Any
1
CA 02592214 2007-06-26
solid material remaining at the completion of the anaerobic digestion process
is typically
disposed of by conventional landfilling or composted into a soil amendment.
151 Because of the high capital costs associated with anaerobic digestion
equipment, and the
environmental issues associated with refuse-to-energy plants, composting has
become the
dominant method in the United States for the management and re-use of organic
waste materials
generated in rural and suburban settings. The growing use of composting as a
preferred
alternative to disposal of organic waste material has also created some
environmental problems.
These problems include emissions of noxious gases and ozone pre-cursors,
runoff from the
compost facility, and high energy consumption during material processing.
These problems may
become particularly acute if the organic waste material contains large amounts
of food waste or
other high moisture content waste.
161 Commercial-scale composting is also subject to a variety of financial
considerations
including capital investment related to accommodating peak seasonal feedstock
deliveries,
compost process time, and controlling the timing of compost production to
match the seasonal
demand of the agricultural industry and other compost buyers. Further, the
compost produced by
these facilities is a low-value product, therefore municipalities have to pay
to have the waste
accepted.
2
CA 02592214 2007-06-26
SUMMARY
[7] An exemplary system for converting organic waste materials comprises a
biomixer, a
first screening apparatus, a hydropulper, and a hydrocyclone. The biomixer is
configured to
convert a first portion of the organic waste materials into a partially
hydrolyzed biomass, and the
first screening apparatus is configured to screen the partially hydrolyzed
biomass into unders that
pass through a screen mesh. The hydropulper is configured to receive the
unders from the first
screening apparatus and to create a slurry therefrom. The hydrocyclone is
configured to remove
grit from the slurry. In some embodiments, the system further comprises a
second screening
apparatus, including a screen mesh, configured to screen a second portion of
the organic waste
materials into unders that pass through the screen mesh and overs that do not,
wherein the
hydropulper is configured to also receive the unders from the second screening
apparatus. In
some of these embodiments, a grinder is configured to grind the unders from
the second
screening apparatus, and the hydropulper is configured to receive the ground
unders. The system
can also comprise a sorting facility configured to remove undesirable
materials from.the organic
waste materials. In some embodiments, the system further comprises an
anaerobic digester
configured to receive the slurry, and some of these embodiments further
comprise a compost
facility configured to receive residual solids from the anaerobic digester.
18] An exemplary method for converting organic waste materials comprises
processing a first
portion of the organic waste materials in a biomixer to create a partially
hydrolyzed biomass,
screening the partially hydrolyzed biomass into unders that pass through a
first screen mesh,
hydropulping the unders to remove heavier and lighter materials and to create
a slurry of the
remainder, and removing grit from the slurry. In some embodiments, the method
further
comprises screening a second portion of the organic waste materials into
unders that pass
3
CA 02592214 2007-06-26
through a second screen mesh and overs that do not pass through the second
screen mesh. In
these embodiments the unders from the second portion of the organic waste
materials are
hydropulped with the unders from the partially hydrolyzed biomass to create
the slurry. In
further embodiments, the overs are processed in the biomixer with the first
portion of the organic
waste materials. In still other embodiments, the slurry is anaerobically
digesting to produce
biogas and a residual solid which can be dewatered and composted. In some
instances, the water
from dewatering the residual solid can be recycled back to hydropulping.
4
CA 02592214 2007-06-26
BRIEF DESCRIPTION OF THE FIGURES
191 FIG. I is schematic representation of a system for the treatment of
organic waste
materials according to an embodiment of the present invention.
lio] FIG. 2 is a schematic representation of a screening apparatus for use in
the system of
FIG. 1.
i1i] FIG. 3 is a schematic representation of a biomixer for use in the system
of FIG. 1.
(12] FIG. 4 is a flowchart representation of exemplary methods of the present
invention.
CA 02592214 2007-06-26
DETAILED DESCRIPTION
1131 Systems and methods are provided for converting organic waste materials
from a
municipal waste stream to useful products. These systems and methods are
capable of receiving
organic waste materials having a wide range of compositions such as, for
example, yard waste,
food waste, paper, and the organic fraction of municipal solid waste (MSW).
The systems and
methods convert the organic waste materials into a uniform biomass that is
suitable for
conversion to useful products, such as fuels. Through the steps of the various
methods, the
organic waste materials are progressively reduced in size and cleaned of
contamination. Final
sizing and cleaning is performed with a hydropulper and a hydrocyclone. A
biomixer is
advantageously provided, prior to the hydropulper, to partially hydrolyze
organic waste materials
that are not initially suitable for processing in the hydropulper. Anaerobic
digestion of the
resulting uniform material, can be employed, for instance, to convert the
uniform biomass to
biogas and a residual solid that is suitable for producing a high quality
compost.
1141 FIG. 1 provides a schematic representation of an exemplary system 100 for
the treatment
of organic waste materials. The system 100 is configured to receive and
process organic waste
materials into a uniform biomass that is a suitable feedstock for conversion
to useful products.
As discussed below, in some embodiments, the components of the system 100 are
sited together
as one facility, while in other embodiments the components are distributed
across more than one
facility and materials have to be transported between them, for example, by
pipeline, truck, or
rail.
1151 The system 100 comprises a receiving area 105, such as a tipping floor,
where the
organic waste materials can be delivered to the system 100, for example, by
municipal garbage
trucks. In some embodiments, the organic waste materials are source separated
before being
6
CA 02592214 2007-06-26
brought to the facility 100, meaning that at the point of collection the
organic waste materials
have been segregated from non-organic waste materials. Source separated
organic waste
materials can comprise, for example, food waste, yard waste, paper, or any
combination thereof,
and can be derived from both residential and commercial sources. A source
separated organic
stream refers to the source separated organic materials of a common type that
are collected from
multiple sources.
1161 An exemplary source separated food waste stream includes processed foods,
vegetable
matter, meat and dairy products, animal fat, vegetable oil, kitchen grease,
and bones. An
exemplary source separated yard waste stream includes branches, grass
clippings, leaves, and
other plant matter. An exemplary source separated paper stream includes
newsprint, junk mail,
paper and cardboard, some contaminated with food, fat, or kitchen grease, and
organic paper
associated with food preparation or consumption such as paper towels, paper
plates, tissue,
waxed paper, and waxed cardboard. Certain businesses can produce highly
specific source
separated organic streams such as sawdust and wood scraps from lumber yards
and bread
products from bakeries.
1171 Thus, source separated organic waste materials can comprise a
veryspecific type of
waste material (e.g., food waste) or a diverse mixture of the various organic
materials noted
above. It is also noted that the composition of a source separated organic
stream can vary over
time. The composition of a source separated yard waste stream, for instance,
will vary with the
seasons and will include a larger fraction of lavAm clippings during the
Spring and Summer
months. As will be described elsewhere herein, the system 100 is able to
accommodate the
compositional range of source separated organic streams.
7
CA 02592214 2007-06-26
p81 As described below, decisions regarding how various organic waste
materials of different
compositions are to be handled by the system 100 can be made, for example, at
the time the
organic waste materials are received in the receiving area 105. Organic waste
materials from
various source separated organic streams can be commingled in the receiving
area 105 before
being further processed, or can be kept separated until later stages of the
processing.
119] The system 100 comprises a sorting facility 110 where various unsuitable
materials can
be removed from the organic waste materials prior to further processing. The
sorting facility 110
can comprise a sorting floor, a sorting line, or both, for example. Depending
on the source of the
organic waste materials, various degrees of sorting may be employed. A sorting
floor is
appropriate where little sorting is required, Nvhile a soriing line is useful
for more significant
sorting. For example, MSW is typically directed to the sorting line. On the
other hand, some
source separated organic ~,aste streams may require a very limited amount of
sorting, for
instance, sawdust and wood debris collected from a lumber mill.
-20] Unsuitable materials typically fall into three categories, hazardous
waste, recyclable
items, and problematic items. Hazardous waste includes materials that would
otherwise
contaminate the end product or pose worker safety problems and includes items
such as batteries,
pesticides, and paint. Recyclable items include such materials as glass,
certain plastics, and
certain metals. Problematic items are those items that are neither hazardous
nor recyclable, but
pose a danger of interfering with the operation of down-stream equipment.
Examples of
problematic items include rope, hose, plastic bags, clothing, buckets, and
other large items.
Hazardous waste can be directed to appropriate disposal, recyclable items can
be directed to
appropriate recycling facilities, and problematic items can be directed to
reuse alternatives,
where appropriate, or landfilling.
8
CA 02592214 2007-06-26
(211 The system 100 further comprises a screening apparatus 115 that can
include, for
example, a trommel, a screening table, a perforated plate, a disc screen, a
finger screen, or a
shaker screen. The screening apparatus 115 is configured to screen the organic
waste materials
into a fraction of the smaller and more desirable "unders" that pass through a
mesh of the
screening apparatus 115 and a residual fraction of "overs" that do not pass
through the screen
mesh. As used herein, the terms "mesh" and "screen mesh" refer to the openings
in the
screening apparatus 115, which can be the square openings defined by a lattice
of wires or the
perforations of a perforated plate, for example. FIG. 2 shows a schematic
representation of a
screening apparatus 200 as described in U.S. Application No. 10/954,550. The
screening
apparatus 200 comprises a screen 210 and an optional mixer 220. The screen 210
in the
illustrated embodiment is a trommel. Mesh sizes for the screen 210 can be at
least P14 inch, in
the range from 2 to 12 inches, and in the range from 4 to 6 inches, in some
embodiments. The
mixer 220 can be used prior to the screen 210, where appropriate, to mix the
organic waste
materials. The mixer 220 serves to break open plastic bags, when present, and
to break apart
larger items such as melon rinds.
1221 For some source separated organic waste streams, such as source separated
food waste,
the unders from the screening apparatus 115 will include the most organics-
rich material, in
other Nvords, the material with the highest volatile solids content. The
overs, on the other hand,
will include more of the less desirable cellulostic material and plastics.
Depending on the
thoroughness of the sorting, the overs can also include unsuitable materials.
In order to optimize
the output of the screening apparatus 115, the mesh size of the screening
apparatus 115 can be
selected based on the composition of the organic waste materials and the
desired quality of the
unders. For a given organic waste stream, a smaller mesh size will increase
the quality of the
9
CA 02592214 2007-06-26
unders, but will also increase the amount of material in the residual
fraction. Thus, the optimum
mesh size for a given organic waste stream is the one that will pass the
largest fraction of the
organic waste stream without causing the unders to drop below a minimum
quality threshold.
1231 In some instances, the unders from the screening apparatus 115 are
directed to a grinder
120, such as grinder 230 shown in FIG. 2. In FIG. 2, the unders are directed
to the grinder 230 to
be ground into a uniform biomass, while the overs can be directed to
composting, landfilling, or
further processing as described below. An exemplary grinder 230 is a vertical-
feed hammer mill.
Exemplary final particle size requirements for the uniform biomass produced by
the grinder 230
specify a maximum particle size and allow for any size distribution below the
maximum, for
example, 3/ inch or less, 1/4 inch or less, and 1/16 inch or less.
124] The system 100 also includes a biomixer 130. The biomixer 130 is a
biomechanical
device described in U.S. Patent Application I''o. 11/584,680. The biomixer 130
employs a
combination of mechanical shearing and biological activity in a controlled
environment to
produce a partially hydrolyzed biomass. An exemplary biomixer 300 is shown in
FIG. 3 and
comprises a rotatable drum 310 that is sloped relative to the horizontal so
that waste material
(represented by arrow 320) introduced at a feed end 330 traverses the biomixer
300 to a
discharge end 340. FIG. 3 also shows an air system for moving air (represented
by arrows 350)
tlu-ough the biomixer 300 and, in some embodiments, for recirculating and/or
recovering volatile
fatty acids from the air 350. Components of the air system that are shown in
FIG. 3 include an
air injector 360, such as a blower, and an air collection device 370, such as
a hood. Adjustments
to the air flow through the drum 310 can be used to control the fermentation
process therein.
The air system can also be used to recover volatile fatty acids from the
environment of the drum
310.
CA 02592214 2007-06-26
1251 The drum 310 includes bacteria capable of facilitating a fermentation
process. The
bacteria can include any bacteria capable of facilitating a fermentation
process, such as
aerotolerant anaerobic bacteria. Aerotolerant anaerobic bacteria are
specialized anaerobic
bacteria characterized by a ferrnentative-type of metabolism. These bacteria
live by fermentation
alone, regardless of the presence of oxygen in their environment. Exemplary
aerotolerant
anaerobic bacteria include species in the genera Desulfomonas, Bulyrivibrio,
Eubacterium,
Lactobacillus, Clostridium, and Ruminococcus.
126l In order to introduce the bacteria into the drum 310, the biological
content of the organic
waste materials can be adjusted, for instahce, by addition of select bacteria
prior to being loaded
into the biomixer 300. The added bacteria can either be a cultured bacteria,
or can be a bacteria
that is recovered from a biomass previously produced by the biomixer 300. In
the latter case, a
small f
raction of the biomass produced by the biomixer 300 is recirculated back into
the organic
waste materials being introduced into the biomixer 300. In some embodiments
the small fraction
of biomass added to the organic ,vaste materials is ten percent or less of the
mass of the incoming
organic waste materials.
(27) As shown in FIG. 1, the partially hydrolyzed biomass produced by the
biomixer 130 is
directed to a screening apparatus 135. The screening apparatus 135 can include
a tronvnel or a
screening table, for example. The screening apparatus 135 is configured to
screen the partially
hydrolyzed biomass into a fraction of unders that pass through a mesh of the
sci-eening apparatus
135 and a residual fraction of overs that do not pass through the screen mesh.
Mesh sizes for the
screen mesh can be at least 1'/ inch, in the range from 2 to 12 inches, and in
the range from 4 to
6 inches, in some embodiments.
11
CA 02592214 2007-06-26
1281 For some source separated organic waste streams, the unders from the
screening
apparatus 135 will include the most organics rich material, and the overs will
include more of the
less desirable cellulostic material and plastics. Depending on the
thoroughness of the sorting, the
overs can also include unsuitable materials. The mesh size of the screening
apparatus 135 can be
selected based on the composition of the organic waste materials and the
desired quality of the
unders in order to optimize the output of the screening apparatus 135. For a
given organic waste
stream, a smaller mesh size will increase the quality of the unders, but will
also increase the
amount of material in the residual fraction. Thus, the optimum mesh size for a
given organic
waste stream is the one that will pass the largest fraction of the organic
waste stream without
causing the unders to drop below a minimum quality threshold. As with the
overs from the
screening apparatus 115, the overs produced by the screening apparatus 135 can
be directed to
composting or a landfill.
1291 The system 100 also comprises a hydropulper 140 including a vessel having
an impeller.
Exemplary hydropulpers are described in U.S. patents 5,377,917 and 6,379,505
both to Wiljan et
al., both incorporated by reference herein. Organic waste materials are mixed
with water in the
vessel and agitated by the impeller. Through the addition of water, the solids
content of the
organic waste materials is reduced in the hydropulper 140 from a typica125 =L
7% solids content
to an 8 2% solids content. Agitation by the impeller creates a slurry and
tends to shear paper
and plastic materials and otherwise causes a reduction in the particle size of
the solids.
1301 Within the hydropulper 140 the heavier materials such a glass, ceramics,
stones, and
metals tend to sink to the bottom, while lighter materials such as plastics
float to the top. The
lighter materials can be removed from the hydropulper 140, for example, be
skimming the top of
the slurry. The heavier materials can be periodically removed from the bottom
of the
12
CA 02592214 2007-06-26
hydropulper 140. The particle size of the solids can be controlled by
withdrawing the slurry
from a level beneath the level of the lighter fraction and screening the
slurry to a typical half inch
to one inch size, or less. The larger particles within the slurry that do not
pass the screen can be
recirculated for additional agitating.
1311 In the manner described above, the hydropulper 140 produces a slurry with
a uniform
particle size that is transferred to a hydrocyclone 145. The hydrocyclone 145
is effective to
remove grit from the slurry, as also described in U.S. patent 5,377,917. The
resulting slurry,
cleaned of grit, can be directed to an anaerobic digester 150. Anaerobic
digestion by the
anaerobic digester 150 produces biogas. The residual solids following
anaerobic digestion can
be dewatered by a dewaterer 1 55. The dewatered residual solids can then be
composted at a
compost facility 160. Hydrocyclones, anaerobic digesters, dewaterers, and
compost facilities are
all well known in the art.
132I As noted above, in some embodiments the components of the system are
located together
in one facility, while in other embodiments the components are distributed
across more than one
facility. For example, the receiving area 105, the sorting facility 110, the
screening apparatus
115 and 135, the ginder 120, and the biomixer 130, can be located in one
facility at or near a
solid waste transfer station while the hydropulper 140, hydrocyclone 145,
anaerobic digester 150
and dewaterer 155 can be located at or near a waste water treatment facility.
The compost
facility 160 can be located at or near the anaerobic digester 150, or located
at yet a third location.
[33] FIG. 4 shows a flowchart representation pertaining to exemplary methods
of processing
organic waste materials through anaerobic digestion to produce biogas and a
high quality
compost. The various methods begin with receiving 405 the organic waste
materials. The
organic waste materials are received 405 in the receiving area 105 (FIG. 1).
In the receiving area
13
CA 02592214 2007-06-26
105 a decision is made regarding wheiher sorting 415 is required, which will
depend on the
nature of the received organic waste materials. Organic waste materials that
do not need sorting
415 are directed to the screening apparatus 115 (FIG: l), while those that do
need sorting 415 are
directed to the sorting facility 110 (FIG. 1).
1341 Determining whether or not to sort 415 the organic waste materials, in
some instances,
relies on a visual inspection of the organic waste materials in the receiving
area 105 to assess the
presence of various unsuitable materials discussed above. If unsuitable
materials are visible, the
organic waste materials are directed to the sorting facility 110, otherwise,
to the screening
apparatus 115. In other instances the outcome of the decision is based on the
type of organic
waste materials without visual inspection. For example, MSW is always directed
to the sorting
facility 110. On the other hand, source separated food -,vaste from reliable
sources that is known
to consistently have very low quantities of unsuitable materials can be
directed to the screening
apparatus 115 without visual inspection. It is noted that even if some
unsuitable materials end up
in the screening apparatus 115, the screening apparatus 115 will tend to
screen those materials
into the overs and out of the overall process.
1351 Another factor to be assessed is whether the organic waste material
includes a sufficient
fraction of smaller particles that are suitable for immediate processing in
the hydropulper 140
(FIG. I). Such a fraction can be readily screened by the screening apparatus
115 to select that
fraction. Materials that are suitable for immediate processing in the
hydropulper 140 are those
that will readily disintegrate in response to agitation in water to form a
slurry. Source separated
food ,vaste ordinarily includes a sufficient fraction of such material. Source
separated yard
waste, on the other hand, typically does not include a sufficient fraction of
smaller particles that
are suitable for immediate processing in the hydropulper 140. These materials
are directed,
14
CA 02592214 2007-06-26
instead, to the biomixer 130 (FIG. 1) affler sorting 415. In sum, a general
rule is that sorting can
be omitted when the organic tvaste materials include a sufficient fraction of
smaller particles that
are suitable for immediate processing in the hydropulper 140 and when the
organic waste
materials are deemed to not include unsuitable materials either by having
passed a visual
inspection or by virtue of being from a reliable source.
1361 Organic waste materials that are deemed to require sorting are then
sorted 415 at the
sorting facility l 10. The sorted organic waste materials is then directed to
be screened 425 if the
sorted organic waste materials include a sufficient fraction of smaller
particles that are suitable
for immediate processing in the hydropulper 140, otherwise the sorted organic
waste materials
are directed to the biomixer. Regardless of whether the sorted organic waste
materials are
screened 425 or sent to the biomixer 130, it should be noted that sorting 415
need not be
exhaustive because in either pathway the organic waste materials will pass
through a screening
apparatus 115 or 135 that will tend to remove unsuitable materials. In
particular, however,
sorting 415 is intended to remove problematic materials that would interfere
with the operation
of the screening apparatus 115 or the biomixer 130. In the case of MSW,
sorting 415 can also be
used to remove recyclable materials.
(37] If the sorted organic ,vaste materials are to be screened 425, then the
organic waste
materials are directed to the screening apparatus 115. Following screening
425, the unders are
directed to the hydropulper 140, and optionally to an intermediate step of
grinding 435.
Grinding 435 can be advantageous in that it reduces the dwell time in the
hydropulper 140 that is
necessary to create a slurry with a sufficiently small particle size. Reducing
the dwell time in the
hydropulper 140 improves the throughput of the hydropulper 140. The overs from
screening 425
CA 02592214 2007-06-26
are preferably directed to the biomixer 130, but can alternatively be directed
to the composting
facility160 or to a landfill.
1381 As noted above, if the soried organic waste materials are not directed to
be screened 425,
then the sorted organic waste materials are directed to be processed 440 in
the biomixer 130.
Processing 440 in the biomixer 130, as described above, takes organic
materials that are not
suitable for immediate processing in the hydropulper 140 and creates a
partially hydrolyzed
biomass that is suitable for hydropulping 445. Prior to hydropulping 445, the
output of the
biomixer 130 is first screened 450 to remove unsuitable rriaterials that were
not previously
removed. These overs can be composted or directed to a landfill.
1391 Nydropulping 445, for example ,vith the hydropulper 140, agitates organic
waste
materials in -,vater to create a slurry and to further separate out
undesirable materials. The
organic waste materials that are hydropulped 445 can be unders from screening
425, ground
unders from grinding 435, or a pariially hydrolyzed and screened biomass from
processing 440
in the biomixer 130. The output from hydropulping 445 is directed to grit
removal 455, for
example, with the hydrocyclone 145 (FIG. 1). Grit remova1455 makes the slurry
less abrasive,
for instance, to pumps.
14o] The slurry, following grit removal 455, is a very uniform biomass product
that is a
suitable feedstock for different processes. In the examples shown herein, the
slurry is next
directed to anaerobic digestion 460, but it will be appreciated that the
slurry can be a feedstock
for conversion to ethanol or other fuels through ,vell known processes. In the
case of anaerobic
digestion 460, the resulting products are biogas and a residual solid. The
residual solid can then
be dewatered 465 and composted 470. The water that is removed can be recycled
back into
hydropulping 445 in those embodiments where the hydropulper 140, anaerobic
digester 150, and
16
CA 02592214 2007-06-26
dewaterer 155 are situated in close proximity to one another. Having been
through a multi-step
sizing and cleaning process, the dewatered residual solids from anaerobic
digestion 460 are ideal
for making a high quality compost.
1411 It will be appreciated that the system 100 and the various processes
outlined by FIG. 4
are highly adaptable. In some instances, for example, it may be more
advantageous to direct
some organic waste materials that would otherwise be suitable for hydropulping
445 instead to
the biomixer 130 simply because extra capacity to receive that material exists
in the biomixer
130 and those materials would otherwise have to ,ait for an extended period
for the hydropulper
140. It will also be appreciated that different types of source separated
waste materials can be
commingled at various points. For instance, source separated paper waste,
though typically
directed out of the present system 100 for paper recycling, can be added as
needed to the
biomixer 130 to decrease the moisture content therein.
1421 In the foregoing specification, the present invention is described with
reference to
specific embodiments the.reof, but those skilled in the art will recognize
that the present
invention is not limited thereto. Various features and aspects of the above-
described present
invention may be used individually or jointly. Further, the present invention
can be utilized in
any number of environments and applications beyond those described herein
without departing
from the broader spirit and scope of the specification. The specification and
drawings are,
accordingly, to be regarded as illustrative rather than restrictive. It will
be recognized that the
terms "comprising," "including," and "having," as used herein, are
specifically intended to be
read as open-ended terms of art.
17
