U.S. patent application number 13/394882 was filed with the patent office on 2012-08-16 for system and method for prevention of adhesion of marine organisms to a substrate contacting with seawater.
This patent application is currently assigned to ECOSPEC GLOBAL TECHNOLOGY PTE. LTD. Invention is credited to Hwee Hong Chew.
Application Number | 20120205246 13/394882 |
Document ID | / |
Family ID | 43731912 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120205246 |
Kind Code |
A1 |
Chew; Hwee Hong |
August 16, 2012 |
SYSTEM AND METHOD FOR PREVENTION OF ADHESION OF MARINE ORGANISMS TO
A SUBSTRATE CONTACTING WITH SEAWATER
Abstract
A system and a method for prevention of adhesion of marine
organisms to a substrate contacted with seawater are provided. The
system comprises a generator (120, 220) for producing an electrical
signal (150) operating in desirable frequencies in which the marine
organisms can be chased or killed, said generator (120, 220) having
at least two output connectors (122, 124, 222, 224), means for
oscillating and propagating the electrical signal (150) along a
surface of the substrate, said means being adapted to make
electrical connection with the at least two output connectors (122,
124, 222, 224) of the generator (120, 220) and being submerged in
seawater, and an electric power source (110, 210) connected to the
generator (122, 124, 222, 224) for applying a selected voltage to
the generator (122, 124, 222, 224) to produce the electrical signal
(150).
Inventors: |
Chew; Hwee Hong; (Singapore,
SG) |
Assignee: |
ECOSPEC GLOBAL TECHNOLOGY PTE.
LTD
SG
|
Family ID: |
43731912 |
Appl. No.: |
13/394882 |
Filed: |
September 8, 2009 |
PCT Filed: |
September 8, 2009 |
PCT NO: |
PCT/CN09/73799 |
371 Date: |
May 2, 2012 |
Current U.S.
Class: |
204/554 ;
204/660 |
Current CPC
Class: |
B63B 59/04 20130101;
C02F 2201/483 20130101; C25F 1/00 20130101; C02F 2201/486 20130101;
C02F 1/48 20130101; C02F 2303/20 20130101; C25F 7/00 20130101 |
Class at
Publication: |
204/554 ;
204/660 |
International
Class: |
B03C 5/00 20060101
B03C005/00; B03C 5/02 20060101 B03C005/02 |
Claims
1. A system for prevention of adhesion of marine organisms to a
substrate contacting with seawater, comprising: a generator for
producing an electrical signal operating with desirable frequencies
which are able to chase or kill the marine organisms, said
generator having at least two output connectors; means for
oscillating and propagating the electrical signal along a surface
of the substrate, said means being adapted to make electrical
connection with the at least two output connectors of the generator
and being submerged in water; and an electric power source
connected to the generator for applying a selected voltage to the
generator to produce the electrical signal.
2. The system as claimed in claim 1, wherein the generator
comprises a card console and a plurality of transistors connected
to the card console to produce the electrical signal having the
frequencies in square wave form.
3. The system as claimed in claim 1, wherein the means for
oscillating and propagating the electrical signal comprises at
least two spaced electrode antennas between which the electrical
signal oscillates and propagates, each of the electrode antennas
being adapted to make electrical connection with the respective
output connectors of the generator.
4. The system as claimed in claim 3, wherein the means for
oscillating and propagating the electrical signal comprises a
plurality of spaced electrode antennas which are arranged in an
array configuration, and the array configuration having two ends
adapted to make electrical connection with the respective output
connectors of the generator.
5. The system as claimed in claim 3, wherein the frequencies
generated by the generator vary in the range of 5 kHz to 200
kHz.
6. The system as claimed in claim 5, wherein the frequencies are
selected in the range of 5 kHz to 50 kHz.
7. The system as claimed in claim 3, wherein the electrodes are
made of a material selected from metal, metal oxide, and
graphite.
8. The system as claimed in claim 3, wherein the electric power
source supplies to the generator a low voltage of 24V, 30V, 36V,
45V or 48V.
9. The system as claimed in claim 1, wherein the means for
oscillating and propagating the electrical signal comprises an
antenna, and a coil wound around the antenna and having two ends
adapted to make electrical connection with the respective output
connectors of the generator.
10. The system as claimed in claim 9, wherein the means for
oscillating and propagating the electrical signal further comprises
a housing in which the antenna and the coil are disposed.
11. The system as claimed in claim 9, wherein the frequencies
generated by the generator vary in the range of 5 kHz to 200
kHz.
12. The system as claimed in claim 11, wherein the frequencies are
selected in the range of 5 kHz to 30 kHz.
13. The system as claimed in claim 9, wherein the antenna is made
of ferrite or a hollow non-metallic tube.
14. The system as claimed in claim 9, wherein the electric power
source supplies to the generator a low voltage of 24V, 30V, 36V,
45V or 48V.
15. A method for prevention of adhesion of marine organisms to a
substrate contacting with seawater, comprising the steps of:
providing a generator for producing an electrical signal operating
with desirable frequencies which are able to chase or kill the
marine organisms, said generator having at least two output
connectors; providing means for oscillating and propagating the
electrical signal, and disposing the means along a surface of the
substrate to be submerged in water, said means being adapted to
make electrical connection with the at least two output connectors
of the generator; and connecting the generator to an electric power
source for applying a selected voltage thereto in order to produce
the electrical signal.
16. The method as claimed in claim 15, wherein the step of
providing the means for oscillating and propagating the electrical
signal comprises providing at least two spaced electrode antennas
between which the electrical signal propagates, each of the
electrode antennas being adapted to make electrical connection with
the respective output connectors of the generator, wherein the
generator produces the electrical signal operating with frequencies
in the range of 5 kHz to 200 kHz.
17. The method as claimed in claim 15, wherein the step of
providing the means for oscillating and propagating the electrical
signal comprises providing an antenna, and a coil wound around the
antenna and having two ends adapted to make electrical connection
with the respective output connectors of the generator, wherein the
generator produces the electrical signal operating with frequencies
in the range of 5 kHz to 200 kHz.
18. The system as claimed in claim 2, wherein the means for
oscillating and propagating the electrical signal comprises at
least two spaced electrode antennas between which the electrical
signal oscillates and propagates, each of the electrode antennas
being adapted to make electrical connection with the respective
output connectors of the generator.
19. The system as claimed in claim 5, wherein the electrodes are
made of a material selected from metal, metal oxide, and
graphite.
20. The system as claimed in claim 2, wherein the means for
oscillating and propagating the electrical signal comprises an
antenna, and a coil wound around the antenna and having two ends
adapted to make electrical connection with the respective output
connectors of the generator.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to the field of prevention
of marine organisms from attaching themselves to a substrate
exposed to seawater, and more particularly, to system and method
for prevention of adhesion of marine organisms to a substrate, such
as ships' hulls, marine vessels, pipelines, contacting with
seawater by use of an electrical signal operating with high
frequencies.
BACKGROUND OF THE INVENTION
[0002] Biofouling or biological fouling is the undesirable
settling, attaching and growing of microorganisms, plants, algae
and/or animals on submerged marine surfaces. The biofouling of
submerged marine surfaces by marine organisms is a well-know
problem. If the accumulation of marine growth on the ships, it can
drastically reduce the ship's speed, increase fuel consumption, and
clog up the seawater cooling, ballast systems or any seawater
intake and discharge lines. Apart from the ship applications,
biofouling control is also necessary for seawater cooling systems
such as power station seawater cooling water intake and condenser
cooling systems. Another problem associated with the biofouling is
that the marine organisms which are native to one water area would
be transported to other areas along with the travelling of the
ship, which inevitably influences the biological system of the
other areas.
[0003] In addition to the biofouling attachment, in many industrial
plant installations, it is necessary to prevent the intrusion of
marine organisms into the seawater cooling system. For examples,
the massive shrimps intrusion into the power plant cooling system
can possibly choke up the filter screens or gates and cause
shutdown of the plant.
[0004] Various methods have been developed to tackle the above
problem, in order to remove the accumulation or prevent the
accumulation of the marine organisms. One of these methods is the
use of bio-dispersants to control the biofouling. Another method,
which is the most commonly used in the art, is to apply paints or
some other type of coatings onto the submerged substrates, in an
attempt to control or prevent attachment of unwanted organisms.
However, most of the paints or coatings have been found to be toxic
to marine organisms, and may be released slowly from the submerged
substrates into the sea water and persist in the water, killing
sealife, harming the environment and possibly entering the food
chain. One of the most effective anti-fouling paints, tributyltin
(TBT) even at an extremely low concentration, has been proven to
cause deformations in oysters and sex changes in whelks. Therefore,
use of these types of paints or coatings has caused damage to the
marine ecosystem, because of their accumulation in water. As such,
International Marine Organization (IMO) has recommended that
measures should be adopted to eliminate the use of anti-fouling
paints or coatings including organtins containing TBT or
triphenyltin (TPT).
[0005] It has been always a major challenge to develop alternative
technologies for the anti-fouling paints or coatings, in order to
prevent fouling on the submerged substrates such as ship's hulls.
To this end, copper and derivative compounds have been successfully
been developed, which are used in the paints though there is still
debate as to the safety of copper.
[0006] Thus, there is a need for a device and a method for
prevention of adhesion of marine organisms to a substrate submerged
in seawater, which is constructively very simple, relatively
inexpensive and more environmentally sound without leaching toxins,
irrespective of whether the substrate is stationary or moving,
however, allows an efficient control or prevent attachment of
unwanted organisms.
SUMMARY OF THE INVENTION
[0007] The present invention has been developed to fulfill the
needs noted above and therefore has a principle object of the
provision of a system for prevention of adhesion of marine
organisms to a substrate contacting with seawater which is
environmentally sound and does not leach toxins into the water.
[0008] Another object of the invention is to provide a system for
prevention of adhesion of marine organisms to a substrate
contacting with seawater which is significantly more economical and
convenient to utilize.
[0009] A yet further object of the invention is to provide a system
for prevention of adhesion of marine organisms to a substrate
contacting with seawater which allows an efficient control or
prevent attachment of unwanted organisms.
[0010] These and other objects and advantages of the invention are
satisfied by providing a system for prevention of adhesion of
marine organisms to a substrate contacting with seawater,
comprising:
[0011] a generator for producing an electrical signal operating
with desirable frequencies which are able to chase or kill the
marine organisms, said generator having at least two output
connectors;
[0012] means for oscillating and propagating the electrical signal
along a surface of the substrate, said means being adapted to make
electrical connection with the at least two output connectors of
the generator and being submerged in water; and
[0013] an electric power source connected to the generator for
applying a selected voltage to the generator to produce the
electrical signal.
[0014] In one preferred embodiment, the generator comprises a card
console and a plurality of transistors connected to the card
console to produce the electrical signal having the frequencies in
square wave form.
[0015] In one particularly preferred embodiment, the means for
oscillating and propagating the electrical signal comprises at
least two spaced electrode antennas between which the electrical
signal oscillates and propagates, each of the electrode antennas
being adapted to make electrical connection with the respective
output connectors of the generator. The frequencies generated by
the generator vary in the range of 5 kHz to 200 kHz, preferably in
the ranger of 5 kHz to 50 kHz, and more preferably in the range of
10 kHz to 15 kHz, of 15 kHz to 20 kHz, or of 5 kH to 10 kHz to 20
kHz.
[0016] A variant of the means for oscillating and propagating the
electrical signal comprises a plurality of spaced electrode
antennas which are arranged in an array configuration, and the
array configuration having two ends adapted to make electrical
connection with the respective output connectors of the generator.
For example, the array configuration may be linear or in the form
of a matrix array.
[0017] According to the invention, the electrodes may be made of a
metal material or metal oxide, or of graphite.
[0018] It would be understood that the shape of the electrode
antennas and the arrangement of the array may be varied according
to the actual requirements.
[0019] Advantageously, the electric power source supplies to the
generator a low voltage of 24V, 30V, 36V, 45V or 48V.
[0020] In another particularly preferred embodiment, the means for
oscillating and propagating the electrical signal comprises an
antenna, and a coil wound around the antenna and having two ends
adapted to make electrical connection with the respective output
connectors of the generator. A housing may be provided, in which
the antenna and the coil are disposed. The frequencies generated by
the generator vary in the range of 5 kHz to 200 kHz, preferably in
the range of 5 kHz to 30 kHz.
[0021] According to the invention, the antenna may be formed as a
ferrite core, or made of a hollow non-metallic tube. Another aspect
of the invention is to provide a method for prevention of adhesion
of marine organisms to a substrate contacting with seawater,
comprising the steps of:
[0022] providing a generator for producing an electrical signal
operating with desirable frequencies which are able to chase or
kill the marine organisms, said generator having at least two
output connectors;
[0023] providing means for oscillating and propagating the
electrical signal, and disposing the means along a surface of the
substrate to be submerged in water, said means being adapted to
make electrical connection with the at least two output connectors
of the generator; and
[0024] connecting the generator to an electric power source for
applying a selected voltage thereto in order to produce the
electrical signal.
[0025] In one embodiment of the invention, the step of providing
the means for oscillating and propagating the electrical signal
comprises providing at least two spaced electrode antennas between
which the electrical signal propagates, each of the electrode
antennas being adapted to make electrical connection with the
respective output connectors of the generator, wherein the
generator produces the electrical signal operating with frequencies
in the range of 5 kHz to 200 kHz.
[0026] In a yet embodiment of the invention, the step of providing
the means for oscillating and propagating the electrical signal
comprises providing an antenna, and a coil wound around the antenna
and having two ends adapted to make electrical connection with the
respective output connectors of the generator, wherein the
generator produces the electrical signal operating with frequencies
in the range of 5 kHz to 200 kHz.
[0027] To have a better understanding of the invention reference is
made to the following detailed description of the invention and
embodiments thereof in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic view of a system for prevention of
adhesion of marine organisms to a substrate contacting with
seawater, which is constructed in accordance with a first
embodiment of the invention.
[0029] FIG. 2 is a schematic top view of a first variant of the
means for oscillating and propagating the electrical signal as
shown in FIG. 1, which is a linear array.
[0030] FIG. 3 is a schematic side view of the variant of FIG.
2.
[0031] FIG. 4 is a schematic view of a second variant of the means
for oscillating and propagating the electrical signal as shown in
FIG. 1, which is in the form of a matrix array.
[0032] FIG. 5 is a schematic view of a system for prevention of
adhesion of marine organisms to a substrate contacting with
seawater, which is constructed in accordance with a second
embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] While this invention is illustrated and described in
preferred embodiments, the system for prevention of adhesion of
marine organisms to a substrate contacting with seawater may be
produced in many different configurations, sizes, forms and
materials.
[0034] Referring now to the drawings, FIG. 1 provides a system 100
constructed consistent with a first embodiment of the present
invention. In this embodiment, the system 100 comprises a power
supply unit 110, a generator 120 for producing electrical signals
operating with desirable frequencies in square wave form, and means
for oscillating and propagating the electrical signals, which means
comprises two spaced electrode antennas 130, 140 submerged in
water.
[0035] The power supply unit 110 is electrically connected to the
generator 120. DC (e.g. battery) and AC power supplies can be used
in the power supply unit 110. Advantageously, the power supply unit
100 further comprises a rectifier for providing direct current
pulse voltage. The power supply unit 110 preferably supplies to the
generator a low voltage of 24V, 30V, 36V, 45V or 48V. It would be
understood that the higher the voltage is, the stronger the
strength outputted by the generator is.
[0036] The generator 120 comprises a card console 126 and a
plurality of transistors 128 connected to the card console 126 to
produce the electrical signals. The generator 120 has two output
connectors 122, 124 which are in electrical connection with the
electrode antennas 130, 140, respectively. The card console 126 has
a variety of ranges of frequency, which all fall into the scope of
desirable frequencies. In this embodiment, the desirable
frequencies are in the range of 5 kHz to 200 kHz, preferably in the
range of 5 kHz to 50 kHz, particularly in the range of 10 kHz to 15
kHz, of 15 kHz to 20 kHz, or of 5 kH to 10 kHz to 20 kHz. For
example, a spike card having a frequency at 5 kHz, 10 kHz and 20
kHz, a trapping card having a frequency at 10 kHz and a normal card
having a frequency ranging from 10 kHz to 15 kHz can be used in the
generator 120. The output current of the card console 126 depends
on the voltage of the power supply applied to the generator 120.
The system 100 consumes low voltage and low current.
[0037] The electrode antennas 130, 140 are disposed to be submerged
in seawater 160 in a spaced apart relation, and electrically
connected to the respective output connectors 122, 124 of the
generator 120, allowing the electrical signals produced by the
generator 120 to oscillate and propagate between the two electrode
antennas 130, 140 via ions and molecules in water. Advantageously,
the electrode antennas 130, 140 are spaced apart such that the
electrical signals 150 operating with the frequencies in the range
of 5 kHz to 50 kHz, which oscillate and propagate between the two
electrode antennas 130, 140 are strong sufficiently to repel, chase
and kill any marine organisms. The electrical field with the
frequencies ranging from 5 kHz to 200 kHz would penetrate and
destroy the nervous systems, muscle control systems, sensing
systems of marine organisms and planktons, thus providing the
protection for the area between the two electrode antennas.
[0038] The electrode antennas can be made of a metal material such
as silver, copper, iron, or metal oxide. Graphite is preferred for
the electrode antennas because it has a low consumption rate in
seawater and can be controlled not to produce chlorine gas in the
system. Therefore, in this embodiment, the electrode antennas are
made of graphite because of its inert characteristics in
seawater.
[0039] As discussed above, the generator 120 produces electrical
signals within the range of 5 kHz to 200 kHz, which signals are
continuously transmitted to the area defined by the two electrode
antennas 130, 140, and then oscillating and propagating within this
area. The strength of the electrical field in this area depends on
the current outputted from the card console 126, the frequencies
produced by the generator 120, the voltage of the power supply and
the distance between the two electrode antennas 130, 140. For
example, in the case that the voltage of the power supply is 48V,
the input DC current of the power supply is 0.87 A, the input DC
current of the card console is 4.5 A, the output DC current of the
card console is 5.1 A, then the electrical field between the
electrode antennas 130, 140 would be strong enough to chase and
kill any living organisms in seawater. The two electrode antennas
may be spaced apart to be, for example, within .mu.m or even more,
which depends on the strength of the electrical field, the water
condition in use, and the actual installation of the system.
[0040] FIGS. 2 to 4 illustrate first and second exemplary variants
of the means for oscillating and propagating the electrical signal
as shown in FIG. 1. In particular, these variants are formed in an
array configuration.
[0041] In FIGS. 2 and 3, the array configuration comprises a
plurality of spaced electrode antennas 171, which is a linear array
170. The alternate antennas 171 in the linear array 170 are in
parallel connection and then electrically connected to the
respective output connectors 122, 124 of the generator 120,
allowing the electrical signals produced by the generator 120 to
oscillate and propagate among the antennas 171 in the array 170. As
illustrated, the area where the electrical fields from the adjacent
antennas 171 overlaps produces the stronger electrical signals.
[0042] In FIG. 4, the array configuration also comprises a
plurality of spaced electrode antennas 181, which is in the form of
matrix array 180. The electrode antennas 181 at each side of this
matrix array 180 are in parallel connection and then electrically
connected to the respective output connectors 122, 124 of the
generator 120, allowing the electrical signals produced by the
generator 120 to oscillate and propagate among the antennas 181 in
the array 180. Like the first array configuration above, the area
where the electrical fields from the adjacent antennas 181 overlaps
produces the stronger electrical signals.
[0043] It would be appreciated that in operation, the adjacent
electrode antennas in the array may be spaced apart from each other
by a distance which is dependent on the strength of the electrical
filed applied, the power supply and the water condition. Actual
arrangement of the array configuration may be altered to suit the
actual application conditions.
[0044] Now referring to FIG. 5, there is illustrated a system 200
constructed consistent with a second embodiment of the present
invention. In this embodiment, the system 200 comprises a power
supply unit 210, a generator 220 for producing electrical signals
operating with desirable frequencies, and means for oscillating and
propagating the electrical signals, which means comprises a ferrite
core antenna 230 and a coil 240 would around the ferrite core
antenna 230 submerged in water.
[0045] Like the first embodiment mentioned above, the power supply
unit 210 is electrically connected to the generator 220. DC and AC
power supplies can be used in the power supply unit 210. The power
supply unit 100 may further comprise a rectifier for providing
direct current pulse voltage. A low voltage of 24V, 30V, 36V, 45V
or 48V is possible for the power supply unit 210.
[0046] The generator 220 comprises a card console 226 and a
plurality of transistors 228 connected to the card console 226 to
produce the electrical signals. The generator 220 has two output
connectors 222, 224 which are in electrical connection with
respective ends of the coil 240. The card console 226 has a variety
of ranges of frequency, which all fall into the scope of desirable
frequencies. In this embodiment, the desirable frequencies are in
the range of 5 kHz to 200 kHz, preferably in the range of 5 kHz to
30 kHz. The output current of the card console 226 depends on the
voltage of the power supply applied to the generator 220.
[0047] The ferrite core antenna 230 and the coil 240 are disposed
within a housing 250, which are then submerged in seawater 260. The
coil 240 has two ends, each of which is electrically connected to
the respective output connector 222, 224 of the generator 220,
allowing the current to flow therethrough so as to generate
electromagnetic waves within the frequencies in the range of 5 kHz
to 200 kHz. As shown in FIG. 5, the electromagnetic field 270 is
then generated within the coil 240 and around the coil 240, which
is able to repel, chase and kill any marine organisms. Any marine
organism, which are subjected to the effects of the electromagnetic
field generated, can detect electromagnetic wave or field in this
range of frequencies, and can be repelled, chased away or killed.
Thus, the protection for the area covered by the electromagnetic
field 270 is provided.
[0048] In addition to the ferrite core antenna, the antenna may be
made of any other ferromagnetic material or a hollow non-metallic
tube. The antenna can act as a magnet to generate the
electromagnetic field when the current flows through the coil. The
number of turns of the coil 240 is determined according to the
current flow through the wire and according to the actual
requirements.
[0049] Like the generator 120 discussed above, the generator 220
produces electrical signals within the range of 5 kHz to 200 kHz,
which signals are continuously transmitted through the ferrite core
antenna 230 to oscillate and propagate electromagnetic signals
generated by the electromagnetic field. Low voltage and low current
are consumed in this system. The strength of the electromagnetic
field depends on the current outputted from the card console 226,
the frequencies produced by the generator 220, the voltage of the
power supply and the size of the ferrite core antenna 230. For
example, in the case that the voltage of the power supply is 48V,
the input DC current of the power supply is 0.87 A, the input DC
current of the power supply is 1.47 A, the input DC current of the
card console is 13 A, and the output DC current of the card console
is 4.8 A, then the electromagnetic field generated by the system
200 would be strong enough to chase and kill any living organisms
in seawater.
[0050] The method of the present invention for prevention of
adhesion of marine organisms to a substrate contacting with
seawater comprises the steps of providing a generator for producing
an electrical signal operating with desirable frequencies which are
able to chase or kill the marine organisms, said generator having
at least two output connectors; providing means for oscillating and
propagating the electrical signal, and disposing the means along a
surface of the substrate to be submerged in water, said means being
adapted to make electrical connection with the at least two output
connectors of the generator; and connecting the generator to an
electric power source for applying a selected voltage thereto in
order to produce the electrical signal.
[0051] Referring back to FIG. 1, the method of the preferred
embodiment comprises providing at least two spaced electrode
antennas 130, 140 between which the electrical signal oscillates
and propagates, each of the electrode antennas being adapted to
make electrical connection with the respective output connectors
122, 124 of the generator 120, wherein the generator 120 produces
the electrical signal operating with frequencies in the range of 5
kHz to 200 kHz.
[0052] Referring to FIG. 5, the method of the preferred embodiment
comprises providing a ferrite core antenna 230, and a coil 240
wound around the ferrite core antenna 230 and having two ends
adapted to make electrical connection with the respective output
connectors 222, 224 of the generator 220, wherein the generator 220
produces the electrical signal operating with frequencies in the
range of 5 kHz to 200 kHz.
[0053] The invention thus provides a system and a method for
prevention of adhesion of marine organisms to a substrate
contacting with seawater which is very simple, relatively
inexpensive and more environmentally sound without leaching toxins,
and which provides an efficient antifouling result.
[0054] While the embodiments described herein are intended as an
exemplary wall lamp fixture, it will be appreciated by those
skilled in the art that the present invention is not limited to the
embodiments illustrated. Those skilled in the art will envision
many other possible variations and modifications by means of the
skilled person's common knowledge without departing from the scope
of the invention, however, such variations and modifications should
fall into the scope of this invention.
* * * * *