(12) United States Patent
`Senkiw
`
`USOO6689262B2
`US 6,689,262 B2
`Feb. 10, 2004
`
`(10) Patent No.:
`(45) Date of Patent:
`
`(54) MICROBUBBLES OF OXYGEN
`(75) Inventor: James Andrew Senkiw, Minneapolis,
`MN (US)
`
`(73) ASSignee: yovation, Inc., Bloomington,
`
`4,908,109 A * 3/1990 Wright ....................... 210/703
`5,049.252 A * 9/1991 Murrell ...................... 204/268
`5,182,014 A
`1/1993 Goodman ................... 209/164
`5,534,143 A * 7/1996 Portier et al. ............... 210/151
`6,315,886 B1 * 11/2001 Zappi et al. ................ 205/701
`6,394,429 B2
`5/2002 Ganan-Calvo ............... 261/77
`6,471,873 B1 * 10/2002 Greenberg et al........... 210/748
`
`(*) Notice:
`
`-
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by O. davs.
`(b) by 0 days
`
`FOREIGN PATENT DOCUMENTS
`WO95/21795
`US
`* 8/1995
`* cited by examiner
`
`(21) Appl. No.: 10/372,017
`(22) Filed:
`Feb. 21, 2003
`(65)
`Prior Publication Data
`US 2003/0164306 A1 Sep. 4, 2003
`
`Related U.S. Application Data
`(60) Provisional application No. 60/358,534, filed on Feb. 22,
`2002.
`(51) Int. Cl. .................................................. C25B 9/00
`(52) U.S. Cl. ................. 2041278.5: 204/272, 204/275.1
`205/755, 205/756; 205/757; 205/758; 205/626;
`s
`s 205(628. 2051633. 205701
`(58) Field of Search ................................. 20575s,756,
`205/757, 758, 626, 628, 633, 701; 204/255
`256 263 266 270 27 275 1, 278 s
`s
`s
`s
`s
`s
`• us
`References Cited
`
`(56)
`
`U.S. PATENT DOCUMENTS
`
`3,975,269 A *
`4.012,319 A *
`4,732,661. A *
`
`8/1976 Ramirez ..................... 210/707
`3/1977 Ramirez ....
`... 210/707
`3/1988 Wright .................... 204/278.5
`
`Primary Examiner Bruce F. Bell
`(74) Attorney, Agent, or Firm- Kathleen R. Terry
`(57)
`ABSTRACT
`An oxygen emitter which is an electrolytic cell is disclosed.
`When the anode and cathode are Separated by a critical
`distance, very small microbubbles and nanobubbles of oxy
`gen are generated. The hydrogen forms bubbles at the
`cathode, which bubbles rise to the surface. The very small
`OXygen bubbles remain in Suspension, forming a Solution
`SuperSaturated in oxygen. The electrodes may be a metal or
`oxide of at least one metal Selected from the group consist
`ing of ruthenium, iridium, nickel, iron, rhodium, rhenium,
`cobalt, tungsten, manganese, tantalum, molybdenum, lead,
`titanium, platinum, palladium and OSmium or oxides thereof.
`The electrodes may be formed into open grids or may be
`closed Surfaces. The most preferred cathode is a stainless
`steel mesh. The most preferred mesh is a /16 inch grid. The
`most preferred anode is platinum and iridium oxide on a
`Support. A preferred Support is titanium. Models Suitable for
`different uses are disclosed.
`
`14 Claims, 5 Drawing Sheets
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`6
`V
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`2
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`-
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`3.
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`Tennant Company
`Exhibit 1006
`
`

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`U.S. Patent
`US. Patent
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`Feb. 10, 2004
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`U.S. Patent
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`Feb. 10, 2004
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`U.S. Patent
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`Feb. 10, 2004
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`Sheet 3 of 5
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`US 6,689,262 B2
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`THERMISTOR
`TEMP
`SENSOR
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`TIMER CONTROL
`CIRCUIT
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`CATHODE
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`Alig. 3
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`U.S. Patent
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`U.S. Patent
`US. Patent
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`Feb. 10, 2004
`Feb. 10, 2004
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`Sheet 5 of 5
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`US 6,689,262 B2
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`

`1
`MICROBUBBLES OF OXYGEN
`
`US 6,689,262 B2
`
`RELATED APPLICATIONS
`This application claim the priority of U.S. Provisional
`Patent Application No. 60/358,534, filed Feb. 22, 2002.
`FIELD OF THE INVENTION
`This invention relates to the electrolytic generation of
`microbubbles of oxygen for increasing the oxygen content
`of aqueous media.
`
`1O
`
`15
`
`25
`
`BACKGROUND OF THE INVENTION
`Many benefits may be obtained through raising the Oxy
`gen content of aqueous media. Efforts have been made to
`achieve higher Saturated or SuperSaturated oxygen levels for
`applications Such as the improvement of water quality in
`ponds, lakes, marshes and reservoirs, the detoxification of
`contaminated water, culture of fish, Shrimp and other aquatic
`animals, biological culture and hydroponic culture. For
`example, fish held in a limited environment Such as an
`aquarium, a bait bucket or a live hold tank may quickly use
`up the dissolved oxygen in the course of normal respiration
`and are then Subject to hypoxic StreSS, which can lead to
`death. A similar effect is seen in cell cultures, where the
`respiring cells would benefit from higher oxygen content of
`the medium. Organic pollutants from agricultural, municipal
`and industrial facilities spread through the ground and
`surface water and adversely affect life forms. Many pollut
`ants are toxic, carcinogenic or mutagenic. Decomposition of
`these pollutants is facilitated by oxygen, both by direct
`chemical detoxifying reactions or by Stimulating the growth
`of detoxifying microflora. Contaminated water is described
`as having an increased biological oxygen demand (BOD)
`and water treatment is aimed at decreasing the BOD So as to
`make more oxygen available for fish and other life forms.
`The most common method of increasing the oxygen
`content of a medium is by Sparging with air or oxygen.
`While this is a simple method, the resulting large bubbles
`produced simply break the Surface and are discharged into
`the atmosphere. Attempts have been made to reduce the size
`of the bubbles in order to facilitate oxygen transfer by
`increasing the total Surface area of the Oxygen bubbles. U.S.
`Pat. No. 5,534,143 discloses a microbubble generator that
`achieves a bubble size of about 0.10 millimeters to about 3
`millimeters in diameter. U.S. Pat. No. 6,394,429 discloses a
`device for producing microbubbles, ranging in size from 0.1
`to 100 microns in diameter, by forcing air into the fluid at
`high pressure through a Small orifice.
`When the object of generating bubbles is to oxygenate the
`water, either air, with an oxygen content of about 21%, or
`pure oxygen may be used. The production of oxygen and
`hydrogen by the electrolysis of water is well known. A
`current is applied across an anode and a cathode which are
`55
`immersed in an aqueous medium. The current may be a
`direct current from a battery or an AC/DC converter from a
`line. Hydrogen gas is produced at the cathode and oxygen
`gas is produced at the anode. The reactions are:
`
`35
`
`40
`
`45
`
`50
`
`AT THE CATHODE:
`AT THE ANODE:
`NET REACTION:
`
`4 HO + 4 e -> 4 OH + 2 H,
`2 HO -> O + 4 H + 4 e.
`6 HO -> 4 OH + 4 H + 2 H., +O,
`
`286 kilojoules of energy is required to generate one mole of
`OXygen.
`
`60
`
`65
`
`2
`The gasses form bubbles which rise to the surface of the
`fluid and may be collected. Either the oxygen or the hydro
`gen may be collected for various uses. The "electrolytic
`water Surrounding the anode becomes acidic while the
`electrolytic water Surrounding the cathode becomes basic.
`Therefore, the electrodes tend to foul or pit and have a
`limited life in these corrosive environments.
`Many cathodes and anodes are commercially available.
`U.S. Pat. No. 5,982,609 discloses cathodes comprising a
`metal or metallic oxide of at least one metal Selected from
`the group consisting of ruthenium, iridium, nickel, iron,
`rhodium, rhenium, cobalt, tungsten, manganese, tantalum,
`molybdenum, lead, titanium, platinum, palladium and
`oSmium. Anodes are formed from the same metallic oxides
`or metals as cathodes. Electrodes may also be formed from
`alloys of the above metals or metals and oxides co-deposited
`on a Substrate. The cathode and anodes may be formed on
`any convenient Support in any desired shape or size. It is
`possible to use the same materials or different materials for
`both electrodes. The choice is determined according to the
`uses. Platinum and iron alloys (“stainless steel”) are often
`preferred materials due to their inherent resistance to the
`corrosive electrolytic water. An especially preferred anode
`disclosed in U.S. Pat. No. 4,252,856 comprises vacuum
`deposited iridium oxide.
`Holding vessels for live animals generally have a high
`population of animals which use up the available oxygen
`rapidly. Pumps to Supply oxygen have high power require
`ments and the noise and bubbling may further StreSS the
`animals. The available electrolytic generators likewise have
`high power requirements and additionally run at high Volt
`ages and produce acidic and basic water which are detri
`mental to live animals. Many of the uses of oxygenators,
`Such as keeping bait or caught fish alive, would benefit from
`portable devices that did not require a Source of high power.
`The need remains for quiet, portable, low Voltage means to
`OXygenate Water.
`
`SUMMARY OF THE INVENTION
`This invention provides an oxygen emitter which is an
`electrolytic cell which generates very small microbubbles
`and nanobubbles of oxygen in an aqueous medium, which
`bubbles are too small to break the Surface tension of the
`medium, resulting in a medium SuperSaturated with Oxygen.
`The electrodes may be a metal or oxide of at least one
`metal Selected from the group consisting of ruthenium,
`iridium, nickel, iron, rhodium, rhenium, cobalt, tungsten,
`manganese, tantalum, molybdenum, lead, titanium,
`platinum, palladium and OSmium or oxides thereof. The
`electrodes may be formed into open grids or may be closed
`Surfaces. The most preferred cathode is a StainleSS Steel
`mesh. The most preferred mesh is a /16 inch grid. The most
`preferred anode is platinum and iridium oxide on a Support.
`A preferred Support is titanium.
`In order to form microbubbles and nanobubbles, the
`anode and cathode are separated by a critical distance. The
`critical distance ranges from 0.005 inches to 0.140 inches.
`The preferred critical distance is from 0.045 to 0.060 inches.
`Models of different size are provided to be applicable to
`various Volumes of aqueous medium to be oxygenated. The
`public is directed to choose the applicable model based on
`Volume and power requirements of projected use. Those
`models with low Voltage requirements are especially Suited
`to oxygenating water in which animals are to be held.
`Controls are provided to regulate the current and timing of
`electrolysis.
`
`

`

`US 6,689,262 B2
`
`3
`DESCRIPTION OF THE DRAWINGS
`FIG. 1 is the O emitter of the invention.
`FIG. 2 is an assembled device.
`FIG. 3 is a diagram of the electronic controls of the O
`emitter.
`FIG. 4 shows a funnel or pyramid variation of the O
`emitter.
`FIG. 5 shows a multilayer sandwich O emitter.
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`5
`
`15
`
`4
`sheet of platinum on a Support of titanium (Eltech, Fairport
`Harbor, Ohio). The cathode 2 is a /16 inch mesh marine
`Stainless Steel Screen. The anode and cathode are separated
`by a non-conducting Spacer 3 containing a gap 4 for the
`passage of gas and mixing of anodic and cathodic water and
`connected to a power Source through a connection point 5.
`FIG. 2 shows a plan view of the assembled device. The O.
`emitter 6 with the anode connecting wire 7 and the cathode
`connecting wire 8 is contained in an enclosure 9, connected
`to the battery compartment 10. The spacer thickness is
`critical as it Sets the critical distance. It must be of Sufficient
`thickness to prevent arcing of the current, but thin enough to
`separate the electrodes by no more than 0.140 inches. Above
`that thickness, the power needs are higher and the oxygen
`bubbles formed at higher Voltage will coalesce and escape
`the fluid. Preferably, the spacer is from 0.005 to 0.075 inches
`thick. At the lower limits, the emitter tends to foul more
`quickly. Most preferably, the spacer is about 0.050 inches
`thick. The Spacer may be any nonconductive material Such
`as nylon, fiberglass, Teflon(E) polymer or other plastic.
`Because of the criticality of the Space distance, it is prefer
`able to have a non-compressible Spacer. It was found that
`Buna, with a durometer measure of 60 was not acceptable
`due to decomposition. Viton, a common fluoroelastomer, has
`a durometer measure of 90 and was found to hold its shape
`well.
`In operation, a small device with an O emitter 1.485
`inches in diameter was driven by 4AA batteries. The critical
`distance was held at 0.050 inches with a Viton spacer. Five
`gallons of water became Saturated in Seven minutes. This
`Size is Suitable for raising oxygen levels in an aquarium or
`bait bucket.
`It is convenient to attach a control circuit which comprises
`a timer that is thermostatically controlled by a temperature
`sensor which determines the off time for the cathode. When
`the temperature of the Solution changes, the resistance of the
`thermistor changes, which causes an off time of a certain
`duration. In cool water, the duration is longer So in a given
`Volume, the emitter generates less oxygen. When the water
`is warmer and therefore hold leSS oxygen, the duration of off
`time is shorter. Thus the device is self-controlled to use
`power most economically. FIG. 3 shows a block diagram of
`a timer control with anode 1, cathode 2, thermistor tempera
`ture Sensor 3, timer control circuit 4 and wire from a direct
`current power Source 5.
`
`Definitions:
`For the purpose of describing the present invention, the
`following terms have these meanings:
`“Critical distance” means the distance Separating the
`anode and cathode at which evolved oxygen forms
`microbubbles and nanobubbles.
`“O2 emitter” means a cell comprised of at least one anode
`and at least one cathode Separated by the critical distance.
`“Metal' means a metal or an alloy of one or more metals.
`"Microbubble' means a bubble with a diameter less than
`50 microns.
`“Nanobubble” means a bubble with a diameter less than
`that necessary to break the Surface tension of water.
`Nanobubbles remain Suspended in the water, giving the
`water an opalescent or milky appearance.
`"SuperSaturated” means Oxygen at a higher concentration
`than normal calculated oxygen Solubility at a particular
`temperature and pressure.
`“Water” means any aqueous medium with resistance leSS
`than one ohm per Square centimeter, that is, a medium that
`can Support the electrolysis of water. In general, the lower
`limit of resistance for a medium that can Support electrolysis
`is water containing more than 2000 ppm total dissolved
`Solids.
`The present invention produces microbubbles and
`nanobubbles of oxygen via the electrolysis of water. AS
`molecular oxygen radical (atomic weight 8) is produced, it
`reacts to form molecular oxygen, O. In the Special dimen
`Sions of the invention, as explained in more detail in the
`following examples, O forms bubbles which are too small
`to break the Surface tension of the fluid. These bubbles
`remain Suspended indefinitely in the fluid and, when allowed
`to build up, make the fluid opalescent or milky. Only after
`Several hours do the bubbles begin to coalesce on the sides
`of the container and the water clears. During that time, the
`water is SuperSaturated with oxygen. In contrast, the H
`45
`formed readily coalesces into larger bubbles which are
`discharged into the atmosphere, as can be seen by bubble
`formation at the cathode.
`The first objective of this invention was to make an
`oxygen emitter with low power demands, low Voltage and
`low current for use with live animals. For that reason, a
`Small button emitter was devised. The anode and cathode
`were Set at varying distances. It was found that electrolysis
`took place at very short distances before arcing of the current
`occurred. Surprisingly, at Slightly larger distances, the water
`became milky and no bubbles formed at the anode, while
`hydrogen continued to be bubbled off the cathode. At
`distance of 0.140 inches between the anode and cathode, it
`was observed that the oxygen formed bubbles at the anode.
`Therefore, the critical distance for microbubble and
`nanobubble formation was determined to be between 0.005
`inches and 0.140 inches.
`EXAMPLE 1.
`Oxygen Emitter
`AS Shown in FIG. 1, the oxygen evolving anode 1 Selected
`as the most efficient is an iridium oxide coated Single sided
`
`25
`
`35
`
`40
`
`EXAMPLE 2
`
`Measurement of O Bubbles
`Attempts were made to measure the diameter of the O
`bubbles emitted by the device of Example 1. In the case of
`particles other than gasses, measurements can easily be
`made by Scanning electron microScopy, but gasses do not
`Survive electron microScopy. Large bubble may be measured
`by pore exclusion, for example, which is also not feasible
`when measuring a gas bubble. A black and white digital,
`high contrast, backlit photograph of treated water with a
`millimeter Scale reference was shot of water produced by the
`emitter of Example 1. About 125 bubbles were seen in the
`area Selected for measurement. Seven bubbles ranging from
`the Smallest clearly Seen to the largest were measured. The
`area was enlarged, giving a Scale multiplier of 0.029412.
`Recorded bubble diameters at Scale were 0.16, 0.22, 0.35,
`0.51, 0.76, 0.88 and 1.09 millimeters. The last three were
`considered outlines by reverse analysis of variance and were
`assumed to be hydrogen bubbles. When multiplied by the
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`US 6,689,262 B2
`
`S
`scale multiplier, the assumed O bubbles were found to
`range from 4.7 to 15 microns in diameter. This test was
`limited by the resolution of the camera and smaller bubbles
`in the nanometer range could not be resolved. It is known
`that white light cannot resolve features in the nanometer size
`range, So monochromatic laser light may give resolution
`Sensitive enough to measure Smaller bubbles. Efforts con
`tinue to increase the Sensitivity of measurement So that
`Sub-micron diameter bubbles can be measured.
`
`EXAMPLE 3
`
`Other Models of Oxygen Emitter
`Depending on the Volume of fluid to be oxygenated, the
`oxygen emitter of this invention may be shaped as a circle,
`rectangle, cone or other model. One or more may be Set in
`a Substrate that may be metal, glass, plastic or other material.
`The Substrate is not critical as long as the current is isolated
`to the electrodes by the nonconductor Spacer material of a
`thickness from 0.005 to 0.075 inches, preferably 0.050
`inches. It has been noticed that the flow of water seems to
`be at the periphery of the emitter, while the evolved visible
`bubbles (H) arise at the center of the emitter. Therefore, a
`funnel or pyramidal shaped emitter was constructed to treat
`larger Volumes of fluid. FIG. 4 is a croSS Sectional diagram
`of Such an emitter. The anode 1 is formed as an open grid
`Separated from a marine grade StainleSS Steel Screen cathode
`2 by the critical distance by Spacer 3 around the periphery of
`the emitter and at the apex. This flow-through embodiment
`is Suitable for treating large Volumes of water rapidly.
`The size may be varied as required. A round emitter for
`oxygenating a bait bucket may be about 2 inches in diameter,
`while a 3-inch diameter emitter is adequate for oxygenating
`a 10 to 40 gallon tank. The live well of a fishing boat will
`generally hold 40 to 80 gallons of water and require a 4-inch
`diameter emitter. It is within the scope of this invention to
`construct larger emitters or to use Several in a Series to
`oxygenate larger Volumes. It is also within the Scope of this
`invention to vary the model to provide for low voltage and
`amperage in cases where the need for oxygen is moderate
`and long lasting or conversely, to SuperSaturate water very
`quickly at higher Voltage and amperage. In the Special
`dimensions of the present invention, it has been found that
`a 6 volt battery Supplying a current as low as 40 milliam
`peres is Sufficient to generate oxygen. Such a model is
`especially useful with live plants or animals, while it is more
`convenient for industrial use to use a higher Voltage and
`current. Table I shows a number of models Suitable to
`various uses.
`
`TABLE I
`
`Emitter Model
`
`Gallons
`
`Volts
`
`Amps Max.
`
`Ave
`
`Watts
`
`Bait keeper
`Livewell
`OEM 2 inch
`Bait store
`Double cycle
`OEM 3 inch
`OEM 4 inch
`Water pail
`Plate
`
`5
`32
`1O
`70
`2
`50
`8O
`2
`250
`
`6
`12
`12
`12
`12
`12
`12
`24
`12
`
`O.O90
`O.18O
`O.210
`O.18O
`O.18O
`O.SOO
`O.98O
`1.2OO
`S.OOO
`
`O.O60
`O.12O
`O.12O
`O.18O
`O.18O
`O.265
`O.410
`1.2OO
`2.5OO
`
`O.36
`1.44
`1.44
`2.16
`2.16
`3.48
`4.92
`28.8O
`3O.OO
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`EXAMPLE 4
`
`Multilayer Sandwich O Emitter
`An O emitter was made in a multilayer Sandwich
`embodiment. (FIG. 5) An iridium oxide coated platinum
`
`65
`
`6
`anode 1 was formed into a grid to allow good water flow and
`Sandwiched between two stainless Steel Screen cathodes 2.
`Spacing was held at the critical distance by nylon Spacers 3.
`The embodiment illustrated is held in a cassette 4 which is
`secured by nylon bolt 5 with a nylon washer 6. The dimen
`Sions Selected were:
`
`cathode screen
`nylon spacer
`anode grid
`nylon spacer
`cathode screen
`
`0.045 inches thick
`0.053 inches thick
`0.035 inches thick
`0.053 inches thick
`0.045 inches thick,
`
`for an overall emitter thickness of 0.231 inches.
`If a more powerful emitter is desired, it is within the Scope
`of this invention to repeat the Sequence of Stacking. For
`example, an embodiment may easily be constructed with
`this sequence: cathode, Spacer, anode, Spacer, cathode,
`Spacer, anode, Spacer, cathode, Spacer, anode, Spacer, cath
`ode. The number of layers in the sandwich is limited only by
`the power requirements acceptable for an application.
`Those skilled in the art will readily comprehend that
`variations, modifications and additions may in the embodi
`ments described herein may be made. Therefore, Such
`variations, modifications and additions are within the Scope
`of the appended claims.
`I claim:
`1. An emitter for electrolytic generation of microbubbles
`of oxygen comprising an anode Separated at a critical
`distance from a cathode and a power Source all in electrical
`communication with each other.
`2. The emitter of claim 1 wherein the anode is a metal or
`a metallic oxide or a combination of a metal and a metallic
`oxide.
`3. The emitter of claim 1 wherein the anode is platinum
`and iridium oxide on a Support.
`4. The emitter of claim 1 wherein the cathode is a metal
`or metallic oxide or a combination of a metal and a metallic
`oxide.
`5. The critical distance of claim 1 which is 0.005 to 0.140
`inches.
`6. The critical distance of claim 1 which is 0.045 to 0.060
`inches.
`7. A method for lowering the biologic oxygen demand of
`polluted water comprising passing the polluted water
`through a vessel containing the emitter of claim 1.
`8. The product of claim 1 wherein the water is Supersatu
`rated with oxygen and of an approximately neutral pH.
`9. An emitter for electrolytic generation of microbubbles
`of oxygen comprising a plurality of anodes Separated at a
`critical distance from a plurality of cathodes and a power
`Source all in electrical communication with each other.
`10. A method for keeping aquatic animals emitter alive
`comprising inserting the emitter of claim 1 or claim 9 into
`the aquatic medium of the aquatic animals.
`11. The method of claim 8 wherein the aquatic animal is
`a fish.
`12. The method of claim 8 wherein the aquatic animal is
`a shrimp.
`13. An emitter for electrolytic generation of microbubbles
`of oxygen comprising a platinum-iridium oxide anode on a
`titanium Support Separated at a critical distance of from
`0.045 inches to 0.060 inches from a stainless steel Screen /16
`inch thick cathode all in electrical communication with a
`battery.
`14. The emitter of claims 1, 9 or 13 further comprising a
`timer control.
`
`