Page 1
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`Meras Ex. 1006
`IPR Petition - USP RE45,550
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`

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`U.S. Patent
`
`Oct. 13, 2009
`
`US 7,601,266 B2
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`12
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`FI[G..]l
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`Page 2
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`EE
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`2:
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`Z 9 5
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`US 7,601,266 B2
`
`1
`METHOD OF PROMOTING UNRESTRICTED
`FLOW OF IRRIGATION WATER THROUGH
`IRRIGATION NETWORKS
`
`TECHNICAL FIELD
`
`This invention relates to a method of promoting unre-
`stricted flow of irrigation water through conduits, filters and
`emitters in an irrigation network. More particularly, it relates
`to the treatment of irrigation water for substantially eliminat-
`ing biofilm formation in the emitters, and for causing mineral
`deposits in the network to be amorphous so that they can be
`easily washed away by the irrigation water.
`
`BACKGROUND OF THE INVENTION
`
`Irrigation water is commonly pumped through filters and
`conduits to emitters which discharge the irrigation water onto
`the plants. It is critical that the designed flow rates be main-
`tained, particularly in low flow (e.g. drip) irrigation networks.
`In these networks, even a small drop in the flow rate will
`damage the plants. As explained in U.S. Pat. No. 6,350,410
`B1, granted Feb. 26, 2002, to Carl E. Iverson and Joyce
`Prindle, biological fouling can develop buildups resulting in
`the loss of flow rate through the irrigation network. It is
`common to feed micronutrients such as iron to promote plant
`growth. When mineral micronutrients are being fed to the
`plants, oxidizers cause them to precipitate out of solution,
`compounding the plugging of low flow emitters. Oxidizers
`such as chlorine gas and hydrogen peroxide have been used to
`treat the irrigation water but such treatment has had a limited
`effect on biofilms and a negative affect on the formation of
`mineral deposits. Oxidizing compounds do not prevent crys-
`talline mineral structures at emitter tips.
`There is a need for a method ofpromoting unrestricted flow
`of irrigation water through the low flow rate emitters that
`discharge the water onto the plants. Specifically, there is a
`need for effectively eliminating both biofilm and mineral
`deposit restrictions and plugging of low flow emitters in irri-
`gation networks.A principal obj ect ofthis invention is to meet
`this need.
`
`BRIEF SUMMARY OF THE INVENTION
`
`The present invention provides a method of substantially
`preserving unrestricted flow of irrigation water through the
`emitters of an irrigation network. The invention comprises
`admixing a biofilm reducing agent (BRA) and a mineral
`deposit distorting agent (MDDA) to the irrigation water. The
`BRA agent substantially eliminates biofilm formation in the
`system. The MDDA agent causes mineral deposits that are
`formed to be amorphous. The BRA and MDDA agents are
`admixed to the irrigation water in amounts sufficient to sub-
`stantially eliminate biofilm formation in the emitters and
`produce amorphous mineral deposits in the emitters that are
`easily washed away by the irrigation water as it flows through
`the emitters.
`
`The BRA agent may be an oxidizer selected from the group
`consisting of chlorine, ozone, chlorine dioxide, hydrogen
`peroxide, peracetic acid, iodine, bromine, hydrogen dioxide,
`chlorate salts, chlorite salts and hypochlorite compounds and
`mixtures thereof. A preferred form of oxidizer is chlorine
`dioxide.
`
`The MDDA agent is selected from the group consisting of
`phosphonate compounds, phosphonic acid compounds,
`derivative of phosphorus, blends of pho sphonate phosphorus
`derivatives, and phosphonic acid compounds, anti-scalent
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`50
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`55
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`60
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`65
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`2
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`polymers, citric acid, acetic acid, mineral acid and mixtures
`thereof. The phosphonate may be selected from the group
`consisting of, but not limited to; ATMP, HEDP, EDTMPA,
`HMDTMPA, DETPMPA, PHMPTMPA, PBTC, HPA, PCA,
`NTMP, and DTPMP. A preferred phosphonate is 2 phospho-
`nobutane-l2, 4 tricarboxylic acid (PBTC).
`These and other objects, advantages, and features will
`become apparent from the detailed description of the best
`mode for carrying out the invention, set forth below.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWINGS
`
`In the drawing, like element designations refer to like parts
`throughout the several views, and:
`FIG. 1 is a system diagram showing irrigation water flow-
`ing into a conduit and BRA and MDDA agents being intro-
`duced into the conduit and admixed with the irrigation water,
`such diagram also showing a plurality of emitters connected
`to the conduit for receiving and discharging irrigation water;
`and
`
`FIG. 2 is an enlarged scale sectional view taken through an
`emitter, showing a relatively small diameter passageway
`extending through the emitter.
`
`DETAILED DESCRIPTION OF THE
`ILLUSTRATED EMBODIMENT
`
`Referring to FIG. 1, a source ofirrigation water 10 is shown
`to be connected to a conduit 12 that leads to a plurality of
`emitters 14. FIG. 1 also shows BRA and MDDA being intro-
`duced into the conduit 12, in admixture with the irrigation
`water. The irrigation water is pumped through the conduit 12
`to and through the emitters 14. The constructional details of
`the emitters 14 are not important. However, the emitters 14
`will have relatively small size passageways 16 for the irriga-
`tion water, making them susceptible to plugging if the irriga-
`tion water does not receive the treatment provided by the
`present invention. For the purpose of this invention, it is
`important that the irrigation water, the BRA and MDDA
`agents form a mixture that flows through the conduit 12 to the
`emitters 14.
`
`The irrigation system shown schematically by FIG. 1 is
`designed to supply water, fertilizer, micronutrients, etc. at
`predetermined flow rates for the particular plants that are
`being watered. The illustrated conduit 12 may be only one of
`a number of conduits 12 that lead from the source 10 to the
`
`plants that are to receive water, nutrients, etc. The plants may
`be in a hothouse, a greenhouse, a vineyard, or in fields.
`The conduits 12 and emitters 14 are susceptible to being
`restricted and/or blocked by both biofilms and crystalline
`mineral deposits formed in the emitters 14. Biofilms are both
`organic and inorganic in nature. They are formed by one or
`more species of bacteria, fungi, algae, protozoa, moss, myce-
`lia, rotatoria, precipitates of fertilizers and source water min-
`erals, viruses, spores, and by debris. The different species
`assist each other with enzymes that breakdown food supplies
`that no single species could assimilate alone. Waste products
`from one species form a food source for another species.
`Pathogens in biofilms are protected by polysaccharide films
`(extracellular polymetric compounds) generated by bacteria.
`It is common to add chelated micronutrients (e.g. chelated
`iron) to the irrigation water to promote plant growth. Iron and
`trace metal salts are food for bacteria such as iron oxidizing
`bacteria and sulfate reducing bacteria (SRBs). Thus, they
`exacerbate the emitter blocking problem by “feeding” the
`biofilm. Also, when chelated mineral micronutrients are
`
`Page 3
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`US 7,601,266 B2
`
`3
`added to the water, oxidizing agents, including chlorine diox-
`ide, cause them to precipitate out of solution, enhancing the
`plugging of the low flow emitters 14.
`Typical sources of the BRA agent are oxidizers selected
`from the group consisting of chlorine, ozone, chlorine diox-
`ide, hydrogen peroxide, peracitic acid,
`iodine, bromine,
`hydrogen dioxide, chlorate salts, chlorite salts and hypochlo-
`rite compounds and mixtures thereof. Example suppliers of
`the MDDA agent are phosphonates from the group consisting
`of phosphonate compounds, phosphonic acid compounds,
`derivative of phosphorus, blends of pho sphonate phosphorus
`derivatives, and phosphonic acid compounds, anti-scalent
`polymers (e.g., polvacrylic acid), citric acid, acetic acid, min-
`eral acid and mixtures thereof. The phosphonates may be
`derived from phosphorus or selected from the group compris-
`ing AMP, ATMP, HEDP, EDTMPA, HMDTMPA, DETP-
`MPA, BHMPTMPA, PBTC, HPA and PCA. The following is
`a list of phosphonates from the Wikipedia Online Encyclo-
`pedia: TABLE-US-00001 PHOSPHONATE COMMER-
`CIAL COMMON NAME NAME NAME CAS #Aminotri
`
`(methylemephosphonicAcid) Dequest 2000 ATMP 6419-19-
`81-Hydroxyethylidene-1,1-Dequest 2010 HEDP 2809-21 -4
`diphosphonic Acid Ethylenediaminetetra Dequest 2041
`EDTMPA 1429-50-1 (methylemephosphonic Acid) Hexam-
`ethylenediarninetetra Dequest 2054 HMDTMPA 38820-59-6
`(methylemephosphonic Acid) Diethylenetriaminepenta
`Dequest 2060 DETPMPA 15827-60-8 (methylemephospho-
`nic Acid) Bis(hexamethylene
`triamine Dequest 2090
`BHMPTMPA 34690-00-1
`penta(methylemephosphonic
`acid))
`2-Phosphonobutane-1,2,4-Dequest
`7000
`PBTC
`37971-36-1 tricarboxylic Acid 2-Hydroxy Phosphonoacetic
`Acid Belcor 575, HPA 23783-26-8 Belelene 494 Phosphi-
`nocarboxylic Acid Belelene 500, PCA 71050-62-9 Beisperse
`1 61
`
`10
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`15
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`20
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`25
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`30
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`4
`tion of the sodium chlorite into chlorine dioxide. The feed of
`the two solutions to the third container was 1500 milliliters
`
`per hour of each solution was introduced into a container. The
`reacted solution from the container was introduced into a 300
`
`gpm flowing water irrigation network that included emitters
`through which the irrigation water was discharged. This irri-
`gation water mixture was used by a greenhouse grower to
`irrigate plants in greenhouses. The grower saved a significant
`amount of money by substantially eliminating plant loss,
`maintenance costs to clean the emitters, filters and the cost of
`replacing the emitters. The mixture flowing through the emit-
`ters contained substantially 3.0 ppm chlorine dioxide, sub-
`stantially 6.0 ppm mixed oxidants and substantially 6.0 ppm
`phosphonate. When these levels were maintained, all issues
`with biofilms, crystalline minerals and fertilizers plugging
`the emitters were eliminated. All mineral deposits were amor-
`phous deposits that were washed away by the irrigation water
`flowing through the emitters.
`
`EXAMPLE 2
`
`A hothouse grower of tomatoes and cucumbers prepared a
`first solution of water (27%), hydroxyethylene dispho sphinic
`acid (18%), and hydrochloric acid (55%) in a first container.
`Water (85%) and sodium chlorite (15%) were mixed in a
`second container to form a second solution. The two solutions
`
`were mixed together in a container to form a food-grade
`composition. This composition was introduced into an irri-
`gation network in which water flow was 760 gpm. The two
`chemical solutions were fed into the container at the rate of
`
`1800 milliliters per hour. The reacted mixture was introduced
`into flowing irrigation water in an irrigation network. The
`
`’HOSPHONATE
`NAME
`
`Aminotri(methylemephosphonic Acid)
`-Hyd.roxyethy1idene-1,1-
`diphosphonic Acid
`Ethylenediaminetetra
`(methylemephosphonic Acid)
`Iexamethylenediaminetetra
`(methylemephosphonic Acid)
`Diethylenetriaminepenta
`(methylemephosphonic Acid)
`3is(hexamethy1ene triamine
`3enta(methy1emephosphonic acid))
`2-Phosphonobutane-1,2,4-
`ricarboxylic Acid
`2-Hydroxy Phosphonoacetic Acid
`
`’hosphinocarboxy1ic Acid
`
`COMMERCIAL COMMON
`NAME
`NAME
`
`Dequest 2000
`Dequest 2010
`
`ATMP
`HEDP
`
`Dequest 2041
`
`EDTMPA
`
`Dequest 2054
`
`HMDTMPA
`
`Dequest 2060
`
`DETPMPA
`
`Dequest 2090
`
`BHMPTMPA
`
`Dequest 7000
`
`PBTC
`
`3e1cor 575,
`3e1c1ene 494
`3e1c1ene 500,
`3e1sperse 161
`
`HPA
`
`PCA
`
`CAS #
`
`6419-19-8
`2809-21-4
`
`1429-50-1
`
`38820-59-6
`
`15827-60-8
`
`34690-00-1
`
`37971-36-1
`
`23783-26-8
`
`71050-62-9
`
`See http://en.wikipedia.org/wiki/phosphonate
`The following are some examples that are submitted for the
`purpose of making it easier to understand the invention:
`
`EXAMPLE 1
`
`acid
`phosphonobutanetricarboxylic
`(27.5%),
`Water
`(17.5%) and hydrochloric acid (55%) were mixed together in
`a solution. Water (85%) and sodium chlorite (15%) were
`mixed together to form a second solution. Suflicient contact
`time was allowed in a container to convert a substantial por-
`
`60
`
`65
`
`mixture of the solutions in the container yielded approxi-
`mately 0.5 ppm chlorine dioxide, approximately 1.0 ppm
`mixed oxidants, and approximately 1.0 ppm phosphonate.
`Water flow rates through the emitters increased from about
`2400 liters per minute to about 3000 liters per minute within
`a five-week period of time. The treatment eliminated plant
`loss due to water and nutrient deprivation and cleaning and
`replacement of water emitters. Accelerated plant growth
`occurred and there was significant increase in food product
`(tomatoes) productivity and the health of the plant root sys-
`tem was improved.
`
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`US 7,601,266 B2
`
`5
`EXAMPLE 3
`
`6
`EXAMPLE 6
`
`A hothouse grower growing certified organic food crops
`(tomatoes), admixed a solution of 80% water, 15% citric acid
`and 5% of acetic acid and another solution of 85% water and
`
`5
`
`15% sodium chlorite into a container. Approximately 65
`ounces ofthe citric acid, acetic acid and water solution and 30
`ounces of the sodium chlorite and water solution were intro-
`
`duced into the container per hour. This solution comprised of
`certified organic components was introduced into 130 gpn1
`flowing irrigation water to yield 1.75 ppm chlorine dioxide
`and 3.5 ppm mixed oxidants. Higher feed rates of the citric
`acid, acetic acid and water compound were fed to distort the
`source water minerals and iron based fertilizers so amorphous
`deposits would be formed, that are easily washed through to
`the irrigation emitters preventing plugging. After four weeks
`oftreatment the pre-filters and emitters were clear ofbiofilms,
`mineral and fertilizer build up. Prior to treatment this grower
`experienced severe plugging of filtration equipment, irriga-
`tion emitters, plant loss, and reduced tomato production. Suf-
`ficient treatment levels were maintained even in this high
`organic environment. To achieve organic certification, this
`grower used a fish-meal based fertilizer, unlike many other
`oxidizers, chlorine dioxide selective reactant nature provided
`treatment residuals and unrestricted irrigation water flow.
`Fish oils were even removed by the application of chlorine
`dioxide, which assisted in preventing the plugging of the
`irrigation network.
`
`EXAMPLE 4
`
`A greenhouse grower cleaned existing crystalline mineral
`formation and biofilm from a section of a glass building
`housing plants and an irrigation network. The fragile new
`plant cuttings were covered with a porous fabric (reme), to
`protect the plants and soils from the erosive nature of the
`overhead irrigation network and disperse the water evenly
`over the plant starts and soils. Irrigation water was used that
`included 3 ppm chlorine dioxide, 7 ppm mixed oxidants, and
`14 ppm phosphonate. The grower experienced the elimina-
`tion of overhead sprinkler plugging due to biofilms, fertilizers
`and crystalline mineral structures. The bacteria count on the
`source-water dropped from 105 to 0 at the emitter. The porous
`fabric (reme) remained free of algae, biofilm and crystalline
`mineral structures allowing proper application of water to the
`new plant cuttings and reduced diseases associated with
`growing in a ur1hygienic environment. The cleaned glass sec-
`tion remained free of crystalline mineral structures, algae and
`biofilm buildup and allowed sunlight infiltration for plant
`photosynthesis.
`
`EXAMPLE 5
`
`A greenhouse grower admixed eighty-eight ounces of a
`solution of 35% PBTC, 10% water and 55% HCL 20 Be with
`eighty-eight ounces of another solution of 15% sodium chlo-
`rite and 85% water in a chamber and fed the reacted compo-
`sition into an overhead irrigation network within the green-
`house flowing at 50 gpm to yield 2 ppm chlorine dioxide and
`4 ppm mixed oxidants and 4 ppm phosphonate. After two
`weeks of maintaining these treatment levels heavy biofilms
`and mineral deposits were removed from the windows, soil
`surfaces and concrete floors. Heavy biofilm buildup was
`removed from the planting tables. Clean windows allowed
`increased plant photosynthesis and overhead irrigating with
`the composition maintained a sterile environment for plant
`propagation and growing which greatly improved issues with
`plant disease.
`
`10
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`A greenhouse grower experiencing severe contamination
`from pathogens and biofilm buildup in an ebb and flow irri-
`gation application. An ebb and flow containment table was
`flooded with irrigation water, fertilizers and nutrients. Differ-
`ent species of plants required variable exposure time to
`uptake the water, fertilizer and nutrients. The water was
`drained from the irrigation table to a holding tank and
`recycled when the plants require additional water, fertilizer
`and nutrients. The watering tables became severely fouled
`with biofilms and mineral deposits. The plant roots exposed
`to the contaminated irrigation water developed a biofilm coat-
`ing that turned the roots brown and hard, killing large portion
`ofthe plants on site and after shipping to greenhouse custom-
`ers. When eighty-eight ounces of a solution of 35% PBTC,
`10% water and 55% hydrochloric acid 20 Be was admixed
`with eighty-eight ounces of a solution of 15% sodium chlorite
`and 85% water in a chamber the resulting composition was
`fed to the irrigation water flowing at 125 gpn1 to the ebb and
`flow tables. Within 4 weeks complete removal ofbiofilms and
`mineral deposits occurred,
`the composition level
`in the
`recycled irrigation water was chlorine dioxide 2 ppm, mixed
`oxidants, 5 ppm and phosphonate 4 ppm. New plants irrigated
`with MDDA and BRA treatment, showed no signs of water
`borne disease and greatly improved the quality of the plants.
`The MDDA distorts the mineral structure so that
`it
`
`becomes an amorphous deposit on the walls of the emitter
`passageways rather than a crystalline structure. The emitter
`passageways are not plugged because the amorphous deposit
`is easily washed away by the irrigation water flowing through
`the system. The presence of the MDDA alone, however, does
`not insure unrestricted-flowing water and nutrients to the
`plants do to issues with biofilms.
`Chlorine dioxide functions essentially independent on pH
`and is an effective biocide in alkaline waters, an important
`advantage. It does not react with water and its eflicacy is the
`same whether it is dissolved in solution or is in a gaseous
`state. Chlorine dioxide is extremely soluble in water, allowing
`it to penetrate and remove biofilms at concentration levels as
`low as 0.5 to 1.0 ppm. It has been found that the reaction of
`chlorite and/or chlorate salts and various acids produces
`residual oxidants (by products) depending upon the type and
`concentration of acids admixed which participate in prevent-
`ing biofilms from plugging the emitters. The slow-release
`action of chlorine dioxide and its lower oxidation strength,
`combined with the mixture of byproduct oxidants provides
`thorough disinfection of very large, low-flow irrigation net-
`works, at low treatment levels.
`The mixed oxidants combined with the chlorine dioxide
`
`tend to be less reactive than strong oxidizers like chlorine gas
`and hydrogen peroxide in the presence of fertilizers, micro-
`nutrient metals, and organic materials, allowing residual oxi-
`dants to be maintained throughout the irrigation network for
`disinfecting in a cost effective manner. The combination of
`chlorine dioxide and the mixed oxidants, together with phos-
`phonic acid compounds, mineral distorting acids and/or anti-
`scalent polymers synergistically resolve all plugging issues
`and maintain unrestricted flow of the irrigation water and
`nutrients through the emitters to the plants. It also reduces the
`spread of pathogens and does not harm the environment like
`other chemicals that are used in the agricultural and golf
`course industries.
`
`Irrigation water treated in accordance with the present
`invention can be used in environments where the plants being
`watered are closely surrounded by architectural structures
`without subjecting them to biofilm and/or crystalline mineral
`
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`US 7,601,266 B2
`
`7
`deposits that adversely effect their functionality and appear-
`ance and are difficult to remove. Sunlight penetration on glass
`with crystalline mineral structures and/or biofilm coatings
`where strong acids are used to remove these crystalline com-
`pounds could damage the glass. This also is true of mineral
`deposits on concrete, building and landscape structures.
`The irrigation water treated in accordance with the present
`invention can be used on golf course greens, fairways, show-
`place lawns, etc. without adverse effect. As previously stated,
`it is common to add micronutrients to the irrigation water, and
`fertilizers, to promote plant growth. This can result in the soil
`base for the golf course greens and fairways becoming quite
`hard, and it can result in the creation of a film consisting of
`mineral/fertilizer and/or biofilm on the soil base that prevents
`rain and irrigation water from penetrating into the soil. It has
`been discovered that the BRA and/or MDDA that are deliv-
`
`ered through the irrigation system conduits and emitters for
`the purpose of substantially maintaining unrestricted flow of
`irrigation water through the conduits and emitters will also
`prevent hardening of the soil and/or the formation of biologi-
`cal film in the soil that prevents the flow of rain and irrigation
`water to the soil.
`
`Some irrigation networks are quite long and include a large
`number of emitters, some of which are spaced a considerable
`distance away from where the BRA and the MDDA are intro-
`duced into the system. Care should be taken in the selection of
`the oxidant (and quantity) used, so that there is a slow-release
`of oxygen of the oxidizer agent and this release continues
`throughout the full length of the irrigation system. It has been
`found that with slow oxidizer agent release the treatment is
`effective throughout the full extent of the irrigation network.
`The disclosed embodiments are only examples of the
`present invention and, therefore, are non-limitive. It is to be
`understood that changes can be made in the particular struc-
`ture, materials, steps and other features of the invention with-
`out departing from the spirit and scope of the invention.
`Therefore, it is my intention that my patent rights not be
`limited by the particular embodiments that are illustrated and
`described herein, but rather are to be determined by the fol-
`lowing claims, interpreted according to accepted doctrines of
`patent claim interpretation, including use of the doctrine of
`equivalents.
`
`What is claimed is:
`
`1. A method of substantially providing unrestricted flow of
`irrigation water through an irrigation network comprising
`water and discharge emitters and conduits that deliver irriga-
`tion water to the emitters, the emitters having small sized
`passageways susceptible to plugging, the method comprising
`the step of:
`admixing a biofilm reducing agent (BRA) and a mineral
`deposit distorting agent (MDDA) with the irrigation
`water, wherein the MDDA is selected from the group
`consisting of phosphonate compounds, phosphonic acid
`compounds, derivatives of phosphorus, blends of phos-
`
`10
`
`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`8
`phonate phosphorus derivatives, and phosphonic acid
`compounds, citric acid, acetic acid, mineral acid and
`mixtures thereof;
`wherein the BRA is an oxidizer that substantially elimi-
`nates biofilm formation;
`wherein the MDDA causes mineral deposits to be amor-
`phous; and
`wherein the BRA and the MDDA are admixed with the
`
`irrigation water in amounts sufficient to substantially
`eliminate biofilm formation in the emitters and produce
`amorphous mineral deposits in the emitters that are
`washed away by the irrigation water as it flows through
`the emitters, wherein plugging of the emitters is elimi-
`nated.
`2. The method of claim 1 wherein the oxidizer is selected
`
`from the group consisting of chlorine, ozone, chlorine diox-
`ide, hydrogen peroxide, hydroxyl peracetic acid, iodine, bro-
`mine, hydrogen dioxide, chlorate salts, chlorite salts,
`hypochlorite compounds and mixtures thereof.
`3. The method of claim 2 wherein the oxidizer is produced
`as a byproduct of a reaction between a chlorite salt and an
`acid.
`4. The method of claim 1 wherein the oxidizer is chlorine
`dioxide.
`
`5. The method of claim 1 wherein the MDDA is a phos-
`phonate.
`6. The method of claim 5 wherein the phosphonate is
`selected from the group consisting of AMP, ATMP, HEDP,
`EDIMPA, HMDTMPA, DETPMPA, BHMPTMPA, PBTC,
`HPA, PCA, NTMP, and DTPMP.
`7. The method of claim 5 wherein the phosphonate is 2
`phosphonobutane-1,2,4 tricarboxylic acid (PBTC).
`8. The method of claim 5 wherein the phosphonate is
`HEDP.
`9. The method of claim 1 wherein the MDDA is selected
`
`from the group consisting of citric acid, acetic acid, mineral
`acid and mixtures thereof.
`
`10. A method comprising the steps of:
`providing an irrigation network having at least one conduit
`leading to at least one emitter having a small sized pas-
`sageway susceptible to plugging, wherein irrigation
`water is directed into and through the at least one conduit
`and into and through the at least one emitter;
`introducing an oxidant and a phosphonate into the irriga-
`tion water; and
`controlling the amount of oxidant and phosphonate intro-
`duced into the irrigation water, such that biofilm forma-
`tion is substantially eliminated and amorphous mineral
`deposits in the emitter are washed away by the irrigation
`water, wherein plugging of the emitter is eliminated.
`11. The method of claim 10 wherein the network is a
`
`stationary network.
`12. The method of claim 10 wherein the network is a
`
`portable network.
`
`Page 6
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`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`APPLICATION NO.
`
`: 7,601,266 B2
`: 11/407414
`
`DATED
`INVENTOR(S)
`
`: October 13, 2009
`: Carl E. Iverson
`
`Page 1 of 1
`
`It is certified that error appears in the above—identified patent and that said Letters Patent is hereby corrected as shown below:
`
`Column 8
`
`Line 29, “EDIMPA” should read --EDTMPA--.
`
`Signed and Sealed this
`
`Eighteenth Day of May, 2010
`
`David J. Kappos
`Director ofthe United States Patent and Trademark Office
`
`Page 7
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`APPLICATION NO.
`
`: 7,601,266 B2
`: 11/407414
`
`DATED
`INVENTOR(S)
`
`: October 13, 2009
`: Carl E. Iverson
`
`Page 1 of 1
`
`It is certified that error appears in the above—identified patent and that said Letters Patent is hereby corrected as shown below:
`
`Title page, item
`
`Subject to any disclaimer, the term of this patent is extended or adjusted under 35
`(*) Notice:
`U.S.C. 154(b) by 364 days.
`
`Delete the phrase “by 364 days” and insert -- by 540 days --.
`
`Signed and Sealed this
`
`Seventeenth Day of August, 2010
`
`David J. Kappos
`Director ofthe United States Patent and Trademark Office
`
`Page 8
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`Page 8
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`

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`US007601266C1
`
`(12) EX PARTE REEXAMINATION CERTIFICATE (9639th)
`United States Patent
`Iverson
`
`US 7,601,266 C1
`(45) Certificate Issued:
`May 9, 2013
`
`(10) Number:
`
`(54) METHOD OF PROMOTING UNRESTRICTED
`FLOW OF IRRIGATION WATER THROUGH
`IRRIGATION NETWORKS
`
`(58) Field of Classification Search
`None
`See application file for complete search history.
`
`(75)
`
`Inventor: Carl E. Iverson, Olympia, WA (US)
`
`(56)
`
`References Cited
`
`(73) Assignee: CH2O, Olympia, WA (US)
`
`Reexamination Request:
`No. 90/011,958, Oct. 14, 2011
`
`Reexamination Certificate for:
`Patent No.:
`7,601,266
`Issued:
`Oct. 13, 2009
`App1.No.:
`11/407,414
`Filed:
`Apr. 20, 2006
`
`Certificate of Correction issued May 18, 2010
`
`Certificate of Correction issued Aug. 17, 2010
`
`(51)
`
`Int. Cl.
`C02F 1/76
`C02F 5/14
`(52) U.S.Cl.
`USPC ......... .. 210/696;210/698;210/699;210/700;
`210/747.5; 210/753; 210/754; 210/756; 210/758;
`210/759; 210/760; 210/764; 422/28; 422/37
`
`(2006.01)
`(2006.01)
`
`To View the complete listing of prior art documents cited
`during the proceeding for Reexamination Control Number
`90/011,958, please refer to the USPTO’s public Patent
`Application Information Retrieval (PAIR) system under the
`Display References tab.
`
`Primary Examiner — Ling Xu
`
`(57)
`
`ABSTRACT
`
`A biofilm reducing agent (BRA) and a mineral deposit dis-
`torting agent (MDDA) are admixed to irrigation water in
`amounts sufficient to substantially eliminate biofilm forma-
`tion in the emitters (14) of an irrigation system (10) and
`produce amorphous mineral deposits in the emitters that are
`easily washed away by the irrigation water as it flows through
`the emitters (14). The BRA may be an oxidizer selected from
`the group consisting of chlorine, ozone, chlorine dioxide,
`hydrogen peroxide, hydroxy peracitic acid, iodine, bromine,
`hydrogen dioxide, chlorate salts, chlorite salts and hypochlo-
`rite compounds and mixtures thereof. The MDDA is a phos-
`phonate selected from the group comprising AMP, ATMP,
`HEDP, EDTMPA, HMDTMPA, DETPMPA, BHMPTMPA,
`PBTC, HPA, PCA, NTMP, and DTPMP.
`
`Page 9
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`
`
`
` IRRIGATION
`WATER
`
`Page 9
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`

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`1
`
`EX PARTE
`
`US 7,601,266 C1
`
`wherein:
`
`2
`
`REEXAMINATION CERTIFICATE
`
`ISSUED UNDER 35 U.S.C. 307
`
`THE PATENT IS HEREBY AMENDED AS
`INDICATED BELOW.
`
`Matter enclosed in heavy brackets [ ] appeared in the
`patent, but has been deleted and is no longer a part of the
`patent; matter printed in italics indicates additions made
`to the patent.
`
`10
`
`AS A RESULT OF REEXAMINATION, IT HAS BEEN
`DETERMINED THAT:
`
`15
`
`Claims 11-12 are cancelled.
`
`Claims 1 and 10 are determined to be patentable as
`amended.
`
`are
`
`Claims 2-9, dependent on an amended claim,
`determined to be patentable.
`1. A method of substantially providing unrestricted flow of
`irrigation water through an irrigation network [comprising]
`designed to supply irrigation water and optional fertilizer
`and micronutrients to plants, wherein the irrigation network
`comprises irrigation water and discharge emitters and con-
`duits that deliver the irrigation water to the emitters, the
`emitters having small sized passageways susceptible to plug-
`ging, the method comprising the step of:
`admixing a biofilm reducing agent (BRA) and a mineral
`deposit distorting agent (MDDA) with the irrigation
`water, wherein the MDDA is selected from the group
`consisting of phosphonate compounds, phosphonic acid
`compounds, derivatives of phosphorus, blends of phos-
`phonate and phosphorus derivatives, [and phosphonic
`acid compounds,] citric acid, acetic acid, mineral acid
`and mixtures thereof;
`
`20
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`25
`
`30
`
`35
`
`the BRA is an oxidizer that substantially eliminates biofilm
`formation;
`
`[wherein] the MDDA causes mineral deposits to be amor-
`phous; [and
`wherein] the BRA and the MDDA are admixed with the
`irrigation water in amounts sufficient to substantially
`eliminate biofilm formation in the emitters and produce
`amorphous mineral deposits in the emitters that are
`washed away by the irrigation water as it flows through
`the emitters[,] ;
`the BRA and the MDDA are admixed with the irrigation
`water such that a ratio of mixed oxidants to chlorine
`dioxide in the irrigation water dischargedfrom the emit-
`ters is 2.'I to 2.5:]; and
`
`[wherein] plugging of the emitters is eliminated.
`10. A method comprising the steps of:
`
`providing an irrigation network [having] designed to sup-
`ply irrigation water to plants, wherein the irrigation
`networkcomprises at least one conduit leading to at least
`one emitter having a small sized passageway susceptible
`to plugging, wherein the irrigation water is directed into
`and through the at least one conduit and into and through
`the at least one emitter;
`
`introducing an oxidant and a phosphonate into the irriga-
`tion water such that a ratio ofmixed oxidants to chlorine
`dioxide in the irrigation water discharged from the at
`least one emitter is 2:] to 2.5:]; and
`
`controlling the amount of oxidant and phosphonate intro-
`duced into the irrigation water, such that biofilm forma-
`tion is substantially eliminated and amorphous mineral
`deposits in the emitter are washed away by the irrigation
`water, wherein plugging of the emitter is eliminated.
`*
`*
`*
`*
`*
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`Page 10
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`Page 10
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