U.S. patent application number 10/235779 was filed with the patent office on 2004-03-11 for siloxane removal system.
This patent application is currently assigned to Pioneer Air Systems, Inc.. Invention is credited to Baseen, Sanjiv K., Sulaiman, Rame.
Application Number | 20040045440 10/235779 |
Document ID | / |
Family ID | 31990562 |
Filed Date | 2004-03-11 |
United States Patent
Application |
20040045440 |
Kind Code |
A1 |
Baseen, Sanjiv K. ; et
al. |
March 11, 2004 |
SILOXANE REMOVAL SYSTEM
Abstract
A method and apparatus for continuously removing siloxanes and
H.sub.2O from a waste gas stream containing H.sub.2O and siloxanes
comprises cooling the waste gas stream in a primary heat exchanger
to a temperature of greater than 32.degree. F. to condense a
portion of the H.sub.2O from the waste gas stream, chilling the
waste gas stream in a first gas-refrigerant heat exchanger to a
temperature of about -20.degree. F. to condense the siloxanes and
freeze the H.sub.2O, and then directing the cooled waste gas stream
from the primary heat exchanger to a second gas-refrigerant heat
exchanger while the first gas-refrigerant heat exchanger is
defrosted to remove frozen H.sub.2O and siloxanes.
Inventors: |
Baseen, Sanjiv K.; (Oak
Ridge, TN) ; Sulaiman, Rame; (Knoxville, TN) |
Correspondence
Address: |
PITTS AND BRITTIAN P C
P O BOX 51295
KNOXVILLE
TN
37950-1295
US
|
Assignee: |
Pioneer Air Systems, Inc.
210 Flatfork Road
Wartburg
TN
37887-3201
|
Family ID: |
31990562 |
Appl. No.: |
10/235779 |
Filed: |
September 5, 2002 |
Current U.S.
Class: |
95/288 ;
62/617 |
Current CPC
Class: |
B01D 53/002
20130101 |
Class at
Publication: |
095/288 ;
062/617 |
International
Class: |
B01D 053/00 |
Claims
Having thus described the aforementioned invention, we claim:
1. An apparatus for removing H.sub.2O and siloxanes from a waste
gas stream containing H.sub.2O and siloxanes, said apparatus
comprising: a source of waste gas containing H.sub.2O and
siloxanes, a primary heat exchanger, a first conduit providing flow
communication for said waste gas from said source to said primary
heat exchanger, a first gas-refrigerant heat exchanger, a second
conduit providing flow communication for said waste gas from said
primary heat exchanger to said first gas-refrigerant heat
exchanger, a second gas-refrigerant heat exchanger, a third conduit
providing flow communication for said waste gas from said primary
heat exchanger to said second gas-refrigerant heat exchanger, and a
valve for alternating the flow of said waste gas stream between
said second conduit and said third conduit.
2. An apparatus as defined in claim 1 and further comprising: a
source of defrosting fluid, a fourth conduit providing flow
communication for said defrosting fluid from said source of
defrosting fluid to said first gas-refrigerant heat exchanger, a
fifth conduit providing flow communication for said defrosting
fluid from said source of defrosting fluid to said second
gas-refrigerant heat exchanger, and a valve for alternating the
flow of said waste gas stream between said fourth conduit and said
fifth conduit, whereby one of said first gas-refrigerant heat
exchanger or said second gas-refrigerant heat exchanger is
defrosted while waste gas is directed to the other of said first
gas-refrigerant heat exchanger or said second gas-refrigerant heat
exchanger.
3. An apparatus as defined in claim 1 wherein said first heat
exchanger comprises a gas-gas heat exchanger.
4. An apparatus as defined in claim 3 wherein cooling gas for said
gas-
4. gas heat exchanger comprises waste gas exiting from said first
gas-refrigerant heat exchanger or said second gas-refrigerant heat
exchanger.
5. An apparatus as defined in claim 1 and further comprising a
secondary heat exchanger within said second conduit.
6. An apparatus as defined in claim 5 wherein said secondary heat
exchanger comprises a gas-gas heat exchanger.
7. An apparatus as defined in claim 6 wherein cooling gas for said
secondary gas-gas heat exchanger comprises waste gas exiting from
said first gas-refrigerant heat exchanger or said second
gas-refrigerant heat exchanger.
8. An apparatus in accordance with claim 1 wherein said
gas-refrigerant heat exchanger comprises an inner shell and an
outer shell.
9. A method of removing siloxanes from a waste gas stream
containing H.sub.2O and siloxanes comprising: cooling said waste
gas stream in a primary heat exchanger to a temperature above
32.degree. F. to condense a portion of said H.sub.2O from said
waste gas stream, chilling said waste gas stream in a first
gas-refrigerant heat exchanger to a temperature of about
-20.degree. F. to condense said siloxanes and freeze H.sub.2O, and
directing said cooled waste gas stream to a second gas-refrigerant
heat exchanger while said first gas-refrigerant heat exchanger is
defrosted to remove frozen H.sub.2O.
10. A method in accordance with claim 9 and further comprising:
cooling said primary heat exchanger with said waste gas stream
exiting said first gas-refrigerant heat exchanger or said second
gas-refrigerant heat exchanger.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of Invention
[0004] This invention pertains to the removal of siloxanes from a
waste gas stream containing siloxanes and H.sub.2O.
[0005] More particularly, this invention pertains to a system for
sequentially removing first H.sub.2O in a primary heat exchanger
and then H.sub.2O and siloxanes in alternating gas-refrigerant heat
exchangers to provide continuous removal of siloxanes from a waste
gas stream.
[0006] A secondary benefit of the invention is the significant
reduction in the amount of numerous other contaminants e.g.
hydrogen sulfide, sulfur dioxide, halogens, volatile organic
compounds (VOC), etc., commonly present in the waste gas stream.
Washing of the gas and solubility of the contaminants in the
condensed moisture, as well as the attraction between neighboring
atoms by van der waals forces cleanse the gas even more and convert
it into a useful "green energy source."
[0007] 2. Description of the Related Art
[0008] Landfills and digesters generate substantial amounts of
waste gas streams containing methane. It is desirable to use this
methane as fuel for boilers, turbines and other energy sources,
particularly in contrast to allowing it to escape into the
atmosphere, where it exacerbates the "greenhouse effect."
Unfortunately, the waste gas streams collected from landfills and
digesters also contain various other organic compounds, some of
which are quite damaging to the boilers, combustion engines,
turbines and the systems used to treat the exhaust gases generated
upon burning the waste gas.
[0009] One family of compounds that has proven to be particularly
troublesome when burning waste gases is siloxanes, cyclic organic
silicon monomers. Siloxanes are widely used as dispersion agents in
various consumer products, including deodorants, shampoos and
shaving cream. In addition, siloxanes are used in a variety of
industrial applications and are periodically discharged in
wastewater. Accordingly, it is quite common for siloxanes to be
found in landfills and wastewater.
[0010] Siloxanes are frequently volatile, having a dew point of
about -9.degree. F., and therefore the waste gas streams from
landfills and digesters generally contain siloxanes. When the waste
gas is burned, the silicon contained in the siloxanes is deposited
on the turbine and engine parts or boiler tubes, for example,
reducing the efficiency of the energy generating equipment. In
addition, the selective catalytic reduction equipment used to
remove NOx is particularly sensitive to fouling by silicon.
[0011] Various efforts have been made to remove siloxanes from the
waste gas streams prior to burning. For example, activated carbon
filters have been used, but the activated carbon must be
regenerated periodically in a kiln. Filtering resins and collection
in methanol and tetraglyme have also been used. Costs have been
prohibitive and regeneration of the resins has proven to be quite
difficult.
[0012] It has been recognized that cooling a waste gas stream to a
temperature of -10.degree. to -20.degree. F. results in
substantially complete removal of siloxanes temperature of
-10.degree. to -20.degree. F. results in substantially complete
removal of siloxanes from a waste gas stream. Ed Wheless and Dan
Gary, Siloxanes in Landfill And Digester Gas, 25th Annual Landfill
Symposium, Solid Waste Association of North America, 2002. However,
chilling the raw waste gas below the freezing temperature of water
rapidly clogs the heat exchanger tubes with frozen condensate.
[0013] It is an object of the present invention to provide a cost
effective system for removing H.sub.2O, siloxanes and other
substances soluble in the condensate from waste gas streams.
[0014] It is also an object of the present invention to provide a
system for continuously removing H.sub.2O, siloxanes and other
substances soluble in the condensate from waste gas streams.
BRIEF SUMMARY OF THE INVENTION
[0015] According to one embodiment of the present invention, a
waste gas stream, which may have a temperature as high as
300.degree. F., is directed to a primary gas-to-gas heat exchanger,
whereby the waste gas is chilled to a temperature close to, but
above, 32.degree. F., to condense a substantial portion of the
H.sub.2O carried in the waste gas stream. The condensing H.sub.2O
also collects a portion of other impurities in the waste gas,
including siloxanes. The cooled waste gas is then directed to a
first of two gas-refrigerant heat exchangers, whereby the
temperature of the waste gas is reduced to about -20.degree. F.
Within the first gas-refrigerant heat exchanger, the remaining
H.sub.2O and the siloxanes are condensed and removed. Over time,
the frozen H.sub.2O begins to block the passage of waste gas
through the first gas-refrigerant heat exchanger. Before a
substantial blockage occurs, the chilled waste gas stream is
diverted to a second gas-refrigerant heat exchanger operating in
substantially the same manner as the first gas-refrigerant heat
exchanger. Simultaneously, the first gas-refrigerant heat exchanger
is defrosted using a defrosting fluid, e.g. a refrigerant, to
remove the frozen H.sub.2O and collected siloxanes. The first and
second gas-refrigerant heat exchangers alternate between freezing
and defrosting cycles to provide continuous removal of H2O and
siloxanes from the waste gas stream.
[0016] The cleansed and dry waste gas stream alternatingly exits
either of the first or second gas-refrigerant heat exchanger at a
temperature of about -20.degree. F. and is used as the coolant gas
for the primary gas-gas heat exchanger that provides initial
cooling of the waste gas, prior to discharge to points of use.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0017] The above-mentioned features of the invention will become
more clearly understood from the following detailed description of
the invention read together with the drawings in which:
[0018] The FIGURE is a schematic diagram of a system embodying
various of the features of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring to the drawings in which like numbers designate
like parts there is disclosed a system for continuously removing
H.sub.2O and siloxanes from a waste gas stream. An inlet conduit
10, including a temperature indicator 12 and a pressure indicator
13, provides flow communication for a waste gas stream to an inlet
14 of a first gas-gas heat exchanger 16. A conduit 18 provides flow
communication for the waste gas stream from an outlet 20 of the
first gas-gas heat exchanger 16 to an inlet 22 of a second gas-gas
heat exchanger 24. The second gas-gas heat exchanger 24 includes a
temperature indicator 25. A conduit 26 provides flow communication
for the waste gas stream from an outlet 28 of the second gas-gas
heat exchanger 24 to an inlet 29 of a tee 30. A drain assembly 32,
comprising an isolation valve 34, a y-strainer 36 and a drain valve
38 extends from the conduit 26.
[0020] The tee 30 includes two outlets 40 and 42. A conduit 44
provides flow communication for waste gas from the tee outlet 40 to
an inlet 46 to an outer shell 50 of a first gas-refrigerant heat
exchanger 48. A conduit 52 provides flow communication for the
waste gas stream from an outlet 54 of the outer shell 50 of the
first gas-refrigerant heat exchanger 48 to an inlet 51 to an inner
shell 132 of the heat exchanger 48. A conduit 55 provides flow
communication from an outlet 54 from the inner shell 132 to a first
inlet 56 of a tee 58. A valve 60 is located in the conduit 55 to
alternately open or close the conduit 55.
[0021] A conduit 62 provides flow communication for waste gas from
the tee outlet 42 to an inlet 64 to an outer shell 68 of a second
gas-refrigerant heat exchanger 66. A conduit 70 provides flow
communication for the waste gas stream from an outlet 67 of the
outer shell 68 to an inlet 71 to an inner shell 148 of the second
gas-refrigerant heat exchanger 66. A conduit 73 provides flow
communication for the waste gas stream from an outlet 72 from the
inner shell 148 to a second inlet 74 of the tee 58. A valve 76 is
located in the conduit 73 to alternately open or close the conduit
73.
[0022] A conduit 78, including a cold, 0.1 micron coalescer filter
81, a temperature indicator 82 and a differential pressure switch
83 provides flow communication for waste gas from the tee outlet 80
to an inlet 84 of a tee 86. A drain assembly 85, similar to the
drain assembly 32, extends from the cold coalescer filter 81.
[0023] A conduit 88 provides flow communication for waste gas from
a first tee outlet 90 to a cooling inlet 92 of the second gas-gas
heat exchanger 24. A conduit 94 provides flow communication for
waste gas from a second tee outlet 96 to a cooling inlet 98 of the
first gas-gas heat exchanger 16. A conduit 100 provides flow
communication for waste gas from a cooling outlet 102 of the second
gas-gas heat exchanger 24 to the conduit 94. A differential
pressure switch 103 is located between conduits 18 and 100. A valve
104 is located in the conduit 94 to alternately open or close the
conduit 94. A conduit 108 provides flow communication for waste gas
from a cooling outlet 108 to a storage, or points of use (not
shown). A carbon filter adsorber 109 is included in the conduit
108.
[0024] The liquid refrigerant for the gas-refrigerant heat
exchangers 48 and 66, which may comprise refrigerant R22, for
example, is re-circulated through the heat exchangers 48 and 66 to
alternatingly cool and heat the contents of the heat exchangers 48
and 66. It will be recognized by those skilled in the art that
indirect cooling, in which another liquid cooled by the refrigerant
is circulated through the heat exchangers 48 and 66, may be used
instead. A compressor 110 is provided for pressurizing the
refrigerant as is known to those skilled in the art. A conduit 112
provides flow communication from an outlet valve 114 to a condenser
116. The condenser 116 may be cooled by air or liquid systems well
known in the art.
[0025] A conduit 120 provides flow communication from the condenser
116 to an inlet 122 of a tee 124. A conduit 126 provides flow
communication from a first outlet 128 to an inlet 130 of the outer
shell of the first gas-refrigerant heat exchanger 48. A valve 131
is located in the conduit 126 to alternately open or close the
conduit 126. A conduit 134 provides flow communication from an
outlet 136 to a first inlet 137 of a tee 135. The conduit 134
includes a check valve 141 to prevent backflow of refrigerant
through the conduit 134.
[0026] A conduit 142 provides flow communication from a second
outlet 144 to an inlet 146 of the outer shell of the second
gas-refrigerant heat exchanger 66. A valve 149 is located in the
conduit 142 to alternately open or close the conduit 142. A conduit
150 provides flow communication from an outlet 152 to a second
inlet 143 of the tee 135. The conduit 150 includes a check valve
154 to prevent backflow of refrigerant through the conduit 134.
[0027] A conduit 145 provides flow communication from the outlet
139 of the tee 135 to an inlet 138 of a tee 140. The conduit 145
includes a liquid line filter 147 and a sight glass 151.
[0028] A conduit 156, including an expansion valve 155, provides
flow communication from a first outlet 158 of the tee 140 to an
inlet 160 of the shell of the first gas-refrigerant heat exchanger
48. A conduit 162 provides flow communication from a gas phase
outlet 164 of the inner shell of the first gas-refrigerant heat
exchanger 48 to a first inlet 166 of a tee 168. A conduit 170
provides flow communication from a liquid phase outlet 172 of the
first gas-refrigerant heat exchanger to the conduit 162. A valve
169 is located in the conduit 162 to alternately open or close the
conduit 162.
[0029] A conduit 174, including an expansion valve 176, provides
flow communication from a second outlet 178 of the tee 140 to the
inner shell of the second gas-liquid heat exchanger 66. A conduit
184 provides flow communication from a gas phase outlet 186 of the
second gas-refrigerant heat exchanger 66 to a second inlet 188 of a
tee 168. A conduit 190 provides flow communication from a liquid
phase outlet 192 of the second heat exchanger to the conduit 184. A
conduit 193 provides flow communication from the outlet 194 of the
tee 168 to the inlet valve 196 of the compressor 110.
[0030] A condensate conduit 198 extends from the first
gas-refrigerant heat exchanger 48 to provide an exit for
condensate. A drain assembly 200, substantially similar to the
drain assembly 32, extends from the conduit 198.
[0031] A condensate conduit 208 extends from the second
gas-refrigerant heat exchanger 66 to provide an exit for
condensate. A drain assembly 210, substantially similar to the
drain assembly 32, extends from the conduit 208.
[0032] A condensate conduit 211 extends from the outer shell of the
second gas-refrigerant heat exchanger 66 to provide an exit for
condensate. A drain assembly 212, substantially similar to the
drain assembly 32, extends from the conduit 211.
[0033] A condensate conduit 213 extends from the outer shell of the
first gas-refrigerant heat exchanger 48 to provide an exit for
condensate. A drain assembly 214, substantially similar to the
drain assembly 32, extends from the conduit 213.
[0034] A condensate conduit 217 extends from the first gas-gas heat
exchanger 16 to provide an exit for condensate. A drain assembly
218, substantially similar to the drain assembly 32, extends from
the conduit 217.
[0035] In operation, waste gas containing H.sub.2O, siloxanes and
other substances, from a digester or landfill, for example, is
directed through the conduit 10 to the inlet 14 of the first
gas-gas heat exchanger 16. The waste gas may be at a temperature of
up to 300.degree. F., but is typically about 120.degree. F. Within
the first gas-gas heat exchanger 16, the waste gas is at a pressure
of about 30 psig and enters at a rate of 5 to 10 SCFM. The cooling
gas flowing in a direction counter to the incoming waste gas is the
fully treated, outgoing, useful waste fuel gas.
[0036] Waste gas exiting from the first gas-gas heat exchanger 16
is directed through the conduit 18 to the inlet 22 of the second
gas-gas heat exchanger 24, wherein the waste gas temperature is
reduced to about 40.degree. F. The cooling gas flowing in a
direction counter to the waste gas is the fully treated waste gas.
It will be recognized by those skilled in the art that at lower
temperatures of incoming waste gas only one gas-gas heat exchanger
may be required. The valve 104 controls flow directly from the tee
86 to the inlet 98 of the first gas-gas heat exchanger 16.
[0037] Within the first gas-gas heat exchanger 16 and the second
gas-gas heat exchanger 24 a substantial portion of the H.sub.2O in
the waste is condensed to water and drained through the drain
assemblies 32 and 218. The condensed water also removes particulate
matter as well as a portion of the siloxanes and other water
soluble substances contained in the waste gas.
[0038] Waste gas exiting from the second gas-gas heat exchanger 24
is directed through the conduit 26 to the inlet 29 of the tee 30.
Initially, the valve 60 is open and the valve 76 is closed to
direct the waste gas through the conduit 44 to the inlet 46 of the
outer shell 50 of the first gas-refrigerant heat exchanger 48. From
the outlet 54 of the outer shell 50, the waste gas flows though the
conduit 52 to the inlet 51 and the tubes of the gas-refrigerant
heat exchanger 48. Within the first gas-refrigerant heat exchanger
48, the waste gas is cooled to a temperature of about -20.degree.
F., below the dew point of siloxanes, to condense for drainage
through the drain assembly 200. The flow rate remains at about 10
scfm and the pressure of the exiting waste gas is about 27
psig.
[0039] Waste gas exiting from the first gas-refrigerant heat
exchanger is directed through the conduit 55, the tee 58 and the
conduit 78 to the cold coalescer filter 81 for removal of any
remaining siloxanes. The temperature and pressure of the waste gas
exiting the cold coalescer filter 81 are monitored by the
temperature indicator 82 and the differential pressure switch 83,
respectively. The exiting waste gas is preferably at a temperature
of -20.degree. F., at a pressure of 26 psig, or higher, and flowing
at a rate of about 10 scfm. The waste gas is directed through the
conduit 78 to the inlet 84 of the tee 86.
[0040] Within the first gas-refrigerant heat exchanger 48, H.sub.2O
is condensed and frozen. Most of the moisture is frozen in the
outer shell 50, which has a higher capacity to hold frozen
condensate. Over a period of time, the waste gas tubes within the
first gas-refrigerant heat exchanger 48 become restricted by ice.
When the differential pressure switches 83 and/or 103 indicate a
pressure drop of greater than 5 psig, for example, a signal is sent
to a central controller (not shown). The controller closes the
valve 60 and opens the valve 76 to direct the waste gas through the
conduit 62 to the inlet 64 of the outer shell 68 of the second
gas-refrigerant heat exchanger 48. Alternatively, the controller
may be programmed to alternatingly cycle the waste gas at
predetermined time intervals through the first gas-refrigerant heat
exchanger 48 and the second gas-refrigerant heat exchanger 66.
[0041] While the waste gas is processed through the second
gas-refrigerant heat exchanger 66 in a manner similar to the first
gas-refrigerant heat exchanger 48, the first gas-refrigerant heat
exchanger 48 is defrosted as described herein below.
[0042] The tee 86 includes a first outlet 90 and a second outlet
96. When the valve 104 is closed, the fully processed waste gas is
directed through the conduit 88 to the inlet 92 of the second
gas-gas heat exchanger 24, where it cools the incoming waste gas to
a temperature of about 40.degree. F. When only one gas-gas heat
exchanger is required to cool incoming waste gas the valve 104 is
opened to direct the processed waste gas through the conduit 94 to
the inlet 98 of the gas-gas heat exchanger 16.
[0043] Processed waste exits the first gas-gas heat exchanger 16 at
a temperature of about 100.degree. F., a pressure of about 25 psig
and at a rate of about 10 scfm.
[0044] In operation, the refrigerant cycle begins at the compressor
110, where the refrigerant, such as refrigerant R22 for example, is
compressed which increases its pressure and temperature. It is then
directed through the conduit 112 to the condenser 116, where the
refrigerant is cooled and condensed into liquid to near the
temperature of its cooling media e.g. ambient air. Initially, the
valve 131 is closed and the valve 149 is open to direct the liquid
refrigerant, usually at about 100.degree. F. through the conduit
120, the tee 124 and the conduit 142 to the inlet 146 of the inner
shell 148 of the second gas-refrigerant heat exchanger 66. After
passage through the second gas-refrigerant heat exchanger 66, where
the liquid refrigerant melts the frozen H.sub.2O for exit through
the drain systems 210 and 212, the liquid phase of the refrigerant
is directed through the outlet 152 and the conduit 150 to the inlet
143 of the tee 135. From the outlet 139 of the tee 135, the liquid
refrigerant is directed through the conduit 145 to the inlet 138 of
the tee 140. From the outlet 158 of the tee 140, the liquid
refrigerant is directed through the conduit 156 and through the
expansion valve 155, where the refrigerant expands and its
temperature is reduced to about -30.degree. F., and then to the
inlet 160 Of the inner-shell of the first gas-refrigerant heat
exchanger 48. After passage through the inner shell 132 of the
first gas-refrigerant heat exchanger 48, the refrigerant is
directed through the outlets 164 and 172 and the conduits 162 and
170, respectively to the inlet 166of the tee 168.
[0045] Before the tubes of the first gas-refrigerant heat exchanger
48 become blocked with frozen H.sub.2O, as sensed by the pressure
differential switches 83 and 103, the valve 169 is closed, the
valve 185 is opened, the valve 131 is opened and the valve 149 is
closed to direct liquid refrigerant from the tee 124 to the inlet
164 of the inner shell 132 of the first gas-refrigerant heat
exchanger 48, where it operates as a defrosting fluid to thaw water
previously frozen in the first gas-refrigerant heat exchanger
48.
[0046] Using the method and apparatus herein described, a waste gas
stream is continuously processed to remove H2O, siloxanes and other
soluble substances. One of the first gas-refrigerant heat exchanger
or the second gas-refrigerant heat exchanger is defrosted while
waste gas is directed to the other of the first gas-refrigerant
heat exchanger or the second gas-refrigerant heat exchanger.
[0047] From the foregoing description, it will be recognized by
those skilled in the art that a novel system for continuously
removing siloxanes and H.sub.2O from a waste gas stream has been
provided.
[0048] While the present invention has been illustrated by
description of several embodiments and while the illustrative
embodiments have been described in considerable detail, it is not
the intention of the applicant to restrict or in any way limit the
scope of the appended claims to such detail. Additional advantages
and modifications will readily appear to those skilled in the art.
The invention in its broader aspects is therefore not limited to
the specific details, representative apparatus and methods, and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of applicant's general inventive concept.
* * * * *