CA2022337A1 - Method of marine pest control by acoustical pulse generated by plasma spark device - Google Patents
Method of marine pest control by acoustical pulse generated by plasma spark deviceInfo
- Publication number
- CA2022337A1 CA2022337A1 CA 2022337 CA2022337A CA2022337A1 CA 2022337 A1 CA2022337 A1 CA 2022337A1 CA 2022337 CA2022337 CA 2022337 CA 2022337 A CA2022337 A CA 2022337A CA 2022337 A1 CA2022337 A1 CA 2022337A1
- Authority
- CA
- Canada
- Prior art keywords
- sparking device
- plasma
- plasma sparking
- underwater
- marine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Abstract
Method of Marine Pest Control by Acoustical Pulses Generated by Plasma Sparking Device ABSTRACT
Certain marine organisms, particularly small mollusks like zebra mussels, are often considerable nuisances when they proliferate on the bottoms of boats, water intake pipes, and other submarine objects. Chemical methods for their control are generally regarded as undesirable because of potentially adverse effects on the marine environment, and much thought in recent years has been given to developing devices which will generate suitable underwater acoustical pulses to kill or damage the organisms over a limited area. Most of these devices have proven impractical for one reason or another. However a plasma sparking device, developed in various versions for underwater depth sounding and seismic imaging, is capable of producing powerful acoustical pulses at tunable frequencies. This characteristic, plus advantages of light weight, controlability, economy and safety, makes the plasma sparking device, or plasma gun, an ideal and key component of an underwater method or system designed to kill or control unwanted marine organisms in a defined area.
Certain marine organisms, particularly small mollusks like zebra mussels, are often considerable nuisances when they proliferate on the bottoms of boats, water intake pipes, and other submarine objects. Chemical methods for their control are generally regarded as undesirable because of potentially adverse effects on the marine environment, and much thought in recent years has been given to developing devices which will generate suitable underwater acoustical pulses to kill or damage the organisms over a limited area. Most of these devices have proven impractical for one reason or another. However a plasma sparking device, developed in various versions for underwater depth sounding and seismic imaging, is capable of producing powerful acoustical pulses at tunable frequencies. This characteristic, plus advantages of light weight, controlability, economy and safety, makes the plasma sparking device, or plasma gun, an ideal and key component of an underwater method or system designed to kill or control unwanted marine organisms in a defined area.
Description
20~2337 ~fethod of Marine Pest Control by ~coustical Pulses Generated by Plasma Sparking ~evice ~ISCLOSIJR~:
(1) This invention relates to a method of killing or otherwise controlling unwanted marine organisms in an underwater environment over a defined area by means of acoustical pulses generated specifically by plasma sparking devices sometimes also referred to as "sparkers" or "plasma guns."
(1) This invention relates to a method of killing or otherwise controlling unwanted marine organisms in an underwater environment over a defined area by means of acoustical pulses generated specifically by plasma sparking devices sometimes also referred to as "sparkers" or "plasma guns."
(2) The propensity of certain marine organisms like mollusks to affix themselves to man made underwater objects has long been a difficult and expensive problem for organizations engaged in marine operations. The most well-known aspect of the problem is the fouling of ships' hulls by marine organisms which can materially retard the progress of a vessel through water.
Recently, a more celebrated aspect of the prob]em has occurred with the invasion of the Great Lakes by a non-indigenous mollusk known as the zebra mussel.
At maturity, the zebra mussel is only a few inches long but it proliferates at a tremendous rate, forming massive colonies on underwater objects. Of most immediate concern has been the way in 202~37 which these colonies have collected around water intake yipes for hydro-electric projects and municipalities, retarding the flow of water and even threatening to block it.
So far the only proven method for controlling the growth of the mussels at water intakes has been the use of chemicals, particularly chlorination. This, however, has proved to be clumsy, expensive and of some potential hazard to the underwater environment.
Also, on the Great Lakes there has been growing concern, resulting in the introduction of controls, about the use of chemicals in anti-fouling paints for the hulls of vessels. It has been concluded that some of the most effective chemicals used in these paints may be having an adverse effect on the marine environment and water quality.
Much thought, therefore, has been given to the development of a practical means of generating acoustical pulses to kill or control unwanted marine animals like zebra mussels in specifiable or highly localized areas. It is well known that the acoustical shock wave of an underwater explosion can locally kill or stun marine animals. An acoustical pulse, generated by similar or other mechanical or electrical means, can have the same local effect.
Finding a practical and controllable method of generating ~ 20~2337 acoustical energy that will adversely affect unwanted marine organisms has been difficult. The use of explosive or mechanical un(lerwater acoustical generators has foundered due to the inability of researchers working with these devices to solve one or several problems involving repeatability, controllability, cost, complexity, bulkiness, efficiency and general effectiveness. For instance, the one-inch air gun which is used to generate acoustical pulses requires a floating platform equivalent to a tug. This makes it vulnerable to the hazards of weather and the sea while limiting how near it can be brought to the underwater target area. The pulses it produces are also spread over a broad band of frequencies thereby limiting the energy available to the those frequencies that may be found to have the optimum deleterious effect on the target organisms.
Electrically operated underwater acoustical generators, however, have existed for many years. They were developed to provide variable sound sources for the seismic exploration of bodies of water and their underlying sediments. One category of these devices involves the creating of an electric arc between two electrodes which, in effect, closely resembles a tiny explosion of T~'T which breaks down the gas or water at the electrodes (creating a "plasma") and generates an acoustical pulse. Known as sparkers or plasma guns, early versions of these devices have required high voltages when submerged to ionize 2 ~ 3 7 the water and create the arc, or mechanical techniques to provide a conductive passage between the electrodes.
Recent improvements in plama gun design have made it a much more efficient and practical source of acoustical energy.
Canadian Patent 1268851 by Reginald Clements et al involves feeding gas to the cavity where the arc is to occur and a means whereby the cavity can be enlarged or diminished to control the size of the plasma plume created at discharge. This makes it possible to control the frequency of the acoustic pulse generated by the spark which is also controlled by the voltage and energy supplied to the electrodes.
A plasma gun can be likened to a automobile spark plug in which the nature of the spark can be controlled by the separation of the electrodes and the amount of current and voltage that is supplied to them. In an underwater application, water is expelled from around the electrodes and replaced by a gas before the arc or spark is created. And like a spark plug, a plasma gun can be fired repeatedly at a high rate.
The plasma gun is attractive for underwater acoustical imaging or seismic exploration because it can be operated at will over a broad range of acoustical frequencies with pulses on far narrower band widths than available from mechanical acoustical generators like air guns. It can also generate acoustical pulses of short wavelengths at ultrasonic frequencies. This has many ;
' " ~ 2~2~7 advantages in terms of acoustical and seismic imaging.
Recently, a more celebrated aspect of the prob]em has occurred with the invasion of the Great Lakes by a non-indigenous mollusk known as the zebra mussel.
At maturity, the zebra mussel is only a few inches long but it proliferates at a tremendous rate, forming massive colonies on underwater objects. Of most immediate concern has been the way in 202~37 which these colonies have collected around water intake yipes for hydro-electric projects and municipalities, retarding the flow of water and even threatening to block it.
So far the only proven method for controlling the growth of the mussels at water intakes has been the use of chemicals, particularly chlorination. This, however, has proved to be clumsy, expensive and of some potential hazard to the underwater environment.
Also, on the Great Lakes there has been growing concern, resulting in the introduction of controls, about the use of chemicals in anti-fouling paints for the hulls of vessels. It has been concluded that some of the most effective chemicals used in these paints may be having an adverse effect on the marine environment and water quality.
Much thought, therefore, has been given to the development of a practical means of generating acoustical pulses to kill or control unwanted marine animals like zebra mussels in specifiable or highly localized areas. It is well known that the acoustical shock wave of an underwater explosion can locally kill or stun marine animals. An acoustical pulse, generated by similar or other mechanical or electrical means, can have the same local effect.
Finding a practical and controllable method of generating ~ 20~2337 acoustical energy that will adversely affect unwanted marine organisms has been difficult. The use of explosive or mechanical un(lerwater acoustical generators has foundered due to the inability of researchers working with these devices to solve one or several problems involving repeatability, controllability, cost, complexity, bulkiness, efficiency and general effectiveness. For instance, the one-inch air gun which is used to generate acoustical pulses requires a floating platform equivalent to a tug. This makes it vulnerable to the hazards of weather and the sea while limiting how near it can be brought to the underwater target area. The pulses it produces are also spread over a broad band of frequencies thereby limiting the energy available to the those frequencies that may be found to have the optimum deleterious effect on the target organisms.
Electrically operated underwater acoustical generators, however, have existed for many years. They were developed to provide variable sound sources for the seismic exploration of bodies of water and their underlying sediments. One category of these devices involves the creating of an electric arc between two electrodes which, in effect, closely resembles a tiny explosion of T~'T which breaks down the gas or water at the electrodes (creating a "plasma") and generates an acoustical pulse. Known as sparkers or plasma guns, early versions of these devices have required high voltages when submerged to ionize 2 ~ 3 7 the water and create the arc, or mechanical techniques to provide a conductive passage between the electrodes.
Recent improvements in plama gun design have made it a much more efficient and practical source of acoustical energy.
Canadian Patent 1268851 by Reginald Clements et al involves feeding gas to the cavity where the arc is to occur and a means whereby the cavity can be enlarged or diminished to control the size of the plasma plume created at discharge. This makes it possible to control the frequency of the acoustic pulse generated by the spark which is also controlled by the voltage and energy supplied to the electrodes.
A plasma gun can be likened to a automobile spark plug in which the nature of the spark can be controlled by the separation of the electrodes and the amount of current and voltage that is supplied to them. In an underwater application, water is expelled from around the electrodes and replaced by a gas before the arc or spark is created. And like a spark plug, a plasma gun can be fired repeatedly at a high rate.
The plasma gun is attractive for underwater acoustical imaging or seismic exploration because it can be operated at will over a broad range of acoustical frequencies with pulses on far narrower band widths than available from mechanical acoustical generators like air guns. It can also generate acoustical pulses of short wavelengths at ultrasonic frequencies. This has many ;
' " ~ 2~2~7 advantages in terms of acoustical and seismic imaging.
(3) The plasma sparking device or plasma gun was developed for underwater exploration but I have discovered it to be the embodiment of a novel method for killing or controlling marine animals like zebra mussels, or other marine organisms, over limited and previously defined areas without adversely affecting the larger underwater environment or water quality. It has advantages over all mechanical devices for generating acoustical energy in that it has a high rate of repeatability, efficiency, operates over a broad range of energies, and can produce pulses on narrow band widths over a much wider range of frequencies which can be pre-selected. It is also compact, lightweight, simple of construction and of operation, can be installed underwater close to the target area, and can be operated remotely.
(4) To achieve the desired effect of killing or controlling marine animals, the mechanical components of a plasma gun consisting of the electrode or electrodes, insulator and outer casing can be installed underwater next to the target area. These components will weigh at most only from two to a hundred pounds.
Gas and electricity can be supplied to the unit remotely, either from shore or from a small floating platform moored above. Where ~ : . -20~2337 necessary due to the mechanical t~nability of the device~
achieved by varying the size of the cavity where the arc occurs, more than one plasma jet can be installed in the target area.
Otherwise, control of the frequencies and energy of the acoustical pulses from the plasma gun will be managed remotely.
The fact that a plasma gun installed underwater can be controlled from the surface will enable an operator to determine by experiment the optimum frequency and energy level of acoustical pulse needed to achieve the desired effect of killing or controlling specific marine animals in the target area. As the plasma gun is capable of producing ultra sonic pulses, it should be possible to find an optimum frequency at which mechanical damage is inflicted on the target animal at various stages in its growth (or possibly even marine plants and single-cell organisms) within a distance from arc source determined by the amount of energy supplied. Also, the operator will have the choice of having the device fire at low energy at a high rate of repetition if this is found to be a suitable way in which to deter marine animals from colonizing the target area.
Thus the plasma sparking device embodies an economical, practical and flexible means of dealing with unwanted marine organisms in an underwater environment within a limited and specified area.
Gas and electricity can be supplied to the unit remotely, either from shore or from a small floating platform moored above. Where ~ : . -20~2337 necessary due to the mechanical t~nability of the device~
achieved by varying the size of the cavity where the arc occurs, more than one plasma jet can be installed in the target area.
Otherwise, control of the frequencies and energy of the acoustical pulses from the plasma gun will be managed remotely.
The fact that a plasma gun installed underwater can be controlled from the surface will enable an operator to determine by experiment the optimum frequency and energy level of acoustical pulse needed to achieve the desired effect of killing or controlling specific marine animals in the target area. As the plasma gun is capable of producing ultra sonic pulses, it should be possible to find an optimum frequency at which mechanical damage is inflicted on the target animal at various stages in its growth (or possibly even marine plants and single-cell organisms) within a distance from arc source determined by the amount of energy supplied. Also, the operator will have the choice of having the device fire at low energy at a high rate of repetition if this is found to be a suitable way in which to deter marine animals from colonizing the target area.
Thus the plasma sparking device embodies an economical, practical and flexible means of dealing with unwanted marine organisms in an underwater environment within a limited and specified area.
Claims (13)
1. A method for killing, damaging or otherwise controlling unwanted marine organisms by means of underwater acoustical pulses generated specifically by a plasma sparking device, sometimes also known as a "sparker" or "plasma gun."
2. A method as defined in claim 1 in which a plasma sparking device is installed underwater for the purpose of generating acoustical pulses in order locally to kill or damage marine organisms or otherwise to control them by limiting their ability to grow or colonize a defined area.
3. A method as claimed in claim 2 in which a plasma sparking device is used to kill or otherwise control zebra mussels.
4. A method as claimed in claim 2 in which a plasma sparking device is used to kill or otherwise control marine animals other than zebra mussels.
5. A method as claimed in claim 2 in which a plasma sparking device is used to kill or otherwise control marine plants.
6. A method as claimed in claim 2 in which a plasma sparking device is used to kill or otherwise control single-cell organisms.
7. A method as claimed in claim 2 in which a plasma sparking device is operated at different energy levels, frequencies and pulse rates.
8. A method as claimed in claim 2 in which a plasma sparking device is located underwater and is operated remotely or from the surface.
9. A method as claimed in claim 2 in which the size of the cavity of a plasma sparking device is adjusted before being installed under water.
10. A method as claimed in claim 2 in which a plasma sparking device is installed underwater in close proximity to a water intake pipe, the hull of a vessel, pipeline controls, oil rig or drilling platform, pier, piling or any other submarine object subject to unwanted fouling by marine organisms.
11. A method as claimed in claim 2 in which various gases are supplied to the cavity of the plasma sparking device.
12. A method as claimed in claim 2 in which the electrodes of the plasma sparking device are made of various metals, alloys or other elements or compounds.
13. A method as claimed in claim 2 in which a plasma sparking device is used to sterilize water or other liquids.
Priority Applications (13)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2022337 CA2022337A1 (en) | 1990-07-31 | 1990-07-31 | Method of marine pest control by acoustical pulse generated by plasma spark device |
| CA002088475A CA2088475C (en) | 1990-07-31 | 1991-07-31 | Zebra mussel (dreissena polymorpha) and other aquatic organism control |
| DK91913427.0T DK0541609T3 (en) | 1990-07-31 | 1991-07-31 | Control of zebra mussel (Dreissena Polymorpha) and other aquatic organisms |
| AU82876/91A AU8287691A (en) | 1990-07-31 | 1991-07-31 | Zebra mussel ((dreissena polymorpha)) and other aquatic organism control |
| US07/972,441 US5432756A (en) | 1990-07-31 | 1991-07-31 | Zebra mussel (Dreissena polymorpha) and other aquatic organism control |
| CN91105947A CN1041075C (en) | 1990-07-31 | 1991-07-31 | Zebra mussel control |
| ES91913427T ES2067947T3 (en) | 1990-07-31 | 1991-07-31 | CONTROL OF ZEBRA MUSSELS (DREISSENA POLIMORFA) AND OTHER TYPES OF AQUATIC ORGANISMS. |
| DE69106711T DE69106711T2 (en) | 1990-07-31 | 1991-07-31 | FIGHTING ZEBRA SHELLS (DREISSENA POLYMORPHA) AND OTHER WATER ORGANISMS. |
| PCT/CA1991/000269 WO1992002926A1 (en) | 1990-07-31 | 1991-07-31 | Zebra mussel (dreissena polymorpha) and other aquatic organism control |
| AT91913427T ATE117117T1 (en) | 1990-07-31 | 1991-07-31 | CONTROL OF ZEBRA MUSSELS (DREISSENA POLYMORPHA) AND OTHER AQUATIC ORGANISMS. |
| PL91294211A PL168256B1 (en) | 1990-07-31 | 1991-07-31 | Method of controlling growth of clams and other waterborne organism |
| EP91913427A EP0541609B1 (en) | 1990-07-31 | 1991-07-31 | Zebra mussel (dreissena polymorpha) and other aquatic organism control |
| GR950400595T GR3015464T3 (en) | 1990-07-31 | 1995-03-20 | Zebra mussel (dreissena polymorpha) and other aquatic organism control. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2022337 CA2022337A1 (en) | 1990-07-31 | 1990-07-31 | Method of marine pest control by acoustical pulse generated by plasma spark device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2022337A1 true CA2022337A1 (en) | 1992-02-01 |
Family
ID=4145599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2022337 Abandoned CA2022337A1 (en) | 1990-07-31 | 1990-07-31 | Method of marine pest control by acoustical pulse generated by plasma spark device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2022337A1 (en) |
-
1990
- 1990-07-31 CA CA 2022337 patent/CA2022337A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |