EP0076121A2 - Procédé et appareil pour la pulvérisation électrostatique de plusieurs liquides - Google Patents
Procédé et appareil pour la pulvérisation électrostatique de plusieurs liquides Download PDFInfo
- Publication number
- EP0076121A2 EP0076121A2 EP82305056A EP82305056A EP0076121A2 EP 0076121 A2 EP0076121 A2 EP 0076121A2 EP 82305056 A EP82305056 A EP 82305056A EP 82305056 A EP82305056 A EP 82305056A EP 0076121 A2 EP0076121 A2 EP 0076121A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- liquid
- cloud
- nozzles
- droplets
- atomized
- 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.)
- Granted
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 78
- 238000005507 spraying Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 13
- 230000002363 herbicidal effect Effects 0.000 claims abstract description 9
- 239000004009 herbicide Substances 0.000 claims abstract description 9
- 239000002917 insecticide Substances 0.000 claims abstract description 7
- 238000007590 electrostatic spraying Methods 0.000 claims description 6
- 239000000126 substance Substances 0.000 abstract description 11
- 239000004480 active ingredient Substances 0.000 abstract 1
- 230000008021 deposition Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 5
- 239000004033 plastic Substances 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 239000012530 fluid Substances 0.000 description 3
- 239000000575 pesticide Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002420 orchard Substances 0.000 description 2
- DHKHKXVYLBGOIT-UHFFFAOYSA-N 1,1-Diethoxyethane Chemical compound CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 description 1
- 229920004943 Delrin® Polymers 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 244000182264 Lucuma nervosa Species 0.000 description 1
- 239000011354 acetal resin Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 230000001846 repelling effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/08—Plant for applying liquids or other fluent materials to objects
- B05B5/085—Plant for applying liquids or other fluent materials to objects the plant being provided on a vehicle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/24—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas with means, e.g. a container, for supplying liquid or other fluent material to a discharge device
- B05B7/26—Apparatus in which liquids or other fluent materials from different sources are brought together before entering the discharge device
Definitions
- the present invention relates to the spraying of liquids and, in particular, to the electrostatic spraying of liquids.
- Spraying apparatus in which a high velocity air stream is used to atomize a liquid issuing from a nozzle for subsequent deposition on a crop or plant.
- the droplets are charged electrostatically as they pass through the outlet duct and thereby improve the deposition of the droplets on the crop.
- Canadian Patent 1,114,427 which issued on December 15, 1981, to I.I. Inculet and G.S.P. Castle, a system is described wherein an electrode is placed in the duct facing the nozzles and connected to one terminal of a high voltage source. The other terminal of the source is connected through the apparatus to ground. An electric charge is induced on the droplets as they are formed in the duct. The charged droplets are attracted electrostatically to the leaves of the crop being sprayed. This has improved the deposition of liquid droplets on the crop and increased the efficiency of the spraying apparatus.
- the droplets are also attracted to ground potential exhibited by the trees, leaves, etc.
- the droplets also repel one another causing the cloud to expand.
- one side of the cloud will tend to expand away from the intended object to be sprayed.
- this loss would be less severe since the spray would usually drift to the next row.
- an atomized cloud of droplets having an electric charge is generated wherein different discrete parts of the cloud are formed from different liquids.
- the discrete part of the cloud which includes an active liquid such as the chemical insecticide or herbicide is contained such as by enveloping it or directing it in a particular direction by a further discrete part of the cloud which includes an inert or inactive liquid, such as water.
- the discrete parts of the cloud may be either horizontal or vertical layers and the liquids used to form the layers may be an inert liquid and/or an active liquid of different concentrations.
- a spraying apparatus comprising a plurality of nozzles positioned in a high velocity air stream to disperse liquid and generate an atomized cloud of such liquid, the nozzles are grouped into at least two sets, each set being arranged to generate a part of the cloud; electrostatic charge generating means is disposed in the air stream downstream of the nozzles to electrostatically charge droplets emitted from the nozzles; a reservoir for each set of nozzles is connected to nozzles to dispense a liquid therefore, through each reservoir containing a different liquid.
- the sets of nozzles may be positioned to generate horizontal or vertical layers in the cloud, each adjacent layer being a different liquid or a liquid having a different concentration of the chemical in question.
- the spraying method in accordance with the present invention further enhances the electrostatic spraying method by using an inexpensive and harmless inert liquid, such as water, in an atomized electrostatic cloud to contain the atomized active liquid, which may be a herbicide or pesticide, by enveloping or directing the atomized active liquid spray.
- active liquid is used to designate the chemical or component one wishes to spray, while the term “inert” or “inactive” liquid is used for liquids which do not have an active coating or chemical ingredient.
- the layers in the atomized electrostatic cloud may be different in size and shape, and also have different droplet charge or droplet density.
- the multilayered cloud gives the necessary flexibility to adjust the factors which influence the desired deposition. For example, if it is necessary, for optimum deposition results to atomize the active liquid, i.e. the insecticide or herbicide, in the form of 20 ⁇ m diameter droplets, these small droplets will be easily entrained by air currents of a few mph velocity. By generating a much larger and/or denser upper cloud layer atomized from an inert liquid to a larger droplet size, such as 50 pm, a much larger deposition force will be produced on the 20 ⁇ m droplets in the lower layer of the cloud.
- the settling velocity for large droplets is greater than for small droplets.
- the settling velocity for a lAm diameter water droplet in -2 air is in the order of 5 x 10 cm/sec, while that of a 50 ⁇ m droplet is in the order fo 10 cm/sec.
- the larger droplets may also fall to the ground or vegetation, and in their fall also entrain some of the small droplets.
- the multilayer cloud provides a good control of the deposition of the expensive chemical formulations, while also eliminating any concern for environmental contamination due to the drifting fractions.
- All of the droplets in a multilayer sprayed cloud would normally have droplets of the same polarity. In general, it is easier to charge effectively larger droplets. Regardless of the level of charging, the identical polarity of the charge on all droplets will ensure cloud expansion and attraction to the vegetation at the same time. By making the upper layer with larger and better charged droplets, the control of the deposition of the lower layer is more easily achieved.
- a cloud could consist of three vertical layers or walls, a center vertical layer of water droplets with a vertical layer of insecticide on each side, all layers being sprayed between two rows of trees.
- the center water layer will perform the repelling function, directing the other two layers into the trees.
- the first layer with the highest concentration is subjected to the strongest electrical forces and will thus penetrate the foliage better than the subsequent layers which will deposit a larger mass mainly at the surface and in the upper part of the foliage.
- spraying apparatus 10 comprises a trailer chassis 12 upon which is mounted a pair of liquid reservoirs 14, 15, and a fan 16, to provide a source of pressurized air.
- the fan 16 may be driven either by the power take-off of a tractor which is conventionally used to draw the spraying apparatus or by a separate prime mover mounted on the trailer.
- the outlet from the fan 16 is directed to a pair of outlet ducts 18 mounted on the rear of the trailer chassis 12.
- Each of the ducts 18 includes a fan shaped shroud 20, each of which is adjust- ably mounted on the outlet ducts for rotation about a generally mounted longitudinal axis. 2
- the shroud 20 can best be seen with reference to figure 2 and comprises a tubular duct 22 connected to a fan-shaped terminal portion 24.
- the terminal portion 24 includes a forward wall 26 and a trailing wall 28.
- the forward and trailing walls are interconnected along their edges to provide a single elongated outlet mouth 30. Air is therefore blown by the fan along the tubular duct 22 and through the terminal portion 24 out of the outlet mouth 30.
- the shroud 20 is dimensioned to provide a high velocity air flow in the region of the fan-shaped terminal portion, typically in the order of 100 to 250 miles per hour.
- a number of nozzles 32 are located on the forward wall 26 of the shroud.
- the nozzles are divided into two sets, names 32a, 32b in the first set, and 32c-32e in the second set.
- Each nozzle in the second set is connected to the liquid reservoir 14 by pipes 34 which are controlled by metering valves 36.
- Each of the nozzles of the first set is connected to reservoir 15 by a pipe 35 controlled by metering valve 37.
- an electrode 38 which is formed out of a plurality of petals 40 interconnected by a conducting strip 42.
- Each of the petals 40 is located opposite a respective nozzle 32 so that fluid issuing from the nozzle will pass the petal.
- the petals 40 are topically of sector shape and are made from a conducting material which may be either a metal or a conducting plastics material. Power is supplied to the electrode 38 by means of a high tension cable 43 imbedded within the trailing wall 28 and connected to a high voltage power pack k4 mounted on the chasis adjacent the fan 16. The high tension power pack is grounded through the vehicle chassis and a trailing conductor 46 so as to be at the same potential as the surrounding environment.
- the nozzle 32 is best seen with reference to figures 3 and 4, and comprises a body 48 with a fluid inlet 50 and a fluid outlet 52.
- the nozzle 32 is formed from a plastic material, preferably by moulding, so that in operation, with a potential being applied to the electrode 38, charge does not accumulate on the nozzle.
- the plastics material may be an acetal resin, such as that sold under the trade name Delrin by DuPont, although any suitable form of non-conducting plastics material may be used.
- the inlet 50 is formed by a tubular conduit 54 passing through the forward wall 26 to receive a pipe 34.
- a nut 56 is threaded onto the outer surface of the conduit 54 to secure the nozzle to the forward wall 26.
- the body is formed with a base 58 which is delimited by an upper edge 60 and a pair of side edges 62.
- Each of the side edges is shaped in the form of an ogee shape and the side edges 62 converge and intersect at a location spaced from the upper edge to define an apex 63 for the base 58.
- a pair of sides walls 64 are connected to the side edges and extend generally perpendicular from the base.
- Each side wall comprises an inner edge 66 which is connected to a respective one of the side edges 62 and an outer edge 68.
- the outer edge is defined by a radius portion 70 which intersects the inner edge 66 at a location corresponding to the apex 63.
- the outer edge is continued by a planar portion 72 which converges with the inner edge 66 toward the upper edge 60 of the base 58.
- An upper wall 74 extends from the apex 63 toward the upper edge 60 of the case 58.
- the upper wall 74 is connected to the outer edges of the side walls 64 and terminates in a trailing edge 76 located intermediate the apex 63 and the upper edge 60.
- the planar portion and radius portion of he outer edge are non-tangential so that an abrupt change in the surface of the upper wall 74 occurs to promote turbulence on the upper wall 74.
- a strengthening or spacer member 78 is provided on the outer surface of the base 58 and may be integrally formed with the base 58.
- the strengthening member 78 is generally tear-shaped and extends around the conduit 54 and up to the upper edge 60.
- the member 78 is of uniform depth so that the base 58 is maintained a constant spacing from the trailing wall 28 of the shroud 20 but side surfaces 80 of the strengthening member converge and intersect at a location corresponding to the upper edge m0.
- the member 78 therefore, provides a streamlined flow of air around the conduit 54 so that air passing between the base 58 and the forward wall. 26 maintains an undisturbed high velocity flow.
- turbulence is created in the air passing over the upper wall face 74 and a pair of contra-rotating vortices are formed at opposite ends of the trailing edge 76.
- air is delivered from the fan through the outlet duct 18 and attains a high velocity in the fan-shaped terminal portion 24.
- a high potential is applied to the electrode 38 and a liquid is delivered from the reservoir through the pipes 34 to the inlet 50 of the nozzle 32.
- Air passing over the upper wall 74 atomizes the liquid delivered to the nozzle to provide droplets which are of a uniform size.
- the droplets acquire a charge as they pass the petals 40 and are carried by the high velocity air stream out of the elongated outlet mouth 30.
- the nozzles of the first set namely 32a, 32b generate a cloud of droplets of the liquid from the reservoir 15 above a predetermined level, denoted A in figure 5.
- the nozzles in the second set namely 32c, d, e, generate a cloud below the level A of the liquid from the reservoir 14.
- the chemical to be applied to the foliage is stored in the reservoir 14 and, therefore, supplied to the second set of nozzles 32c-e.
- the reservoir 15 contains an inert liquid, such as water, which is supplied to the first set of nozzles 32a, b.
- the cloud above level A is, therefore, composed of essentially water whereas the cloud below level A is composed of the herbicide or pesticide with which the foliage is to be treated. It will be apparent, therefore, that substantially all the droplets of chemical are positively forced to the foliage whereas the dispersed droplets consist only of water. This reduces hazards caused by drifting and also reduces the consumption of the chemical.
- the same apparatus may be used to provide vertically layered clouds, such as by supplying one liquid to all of the nozzles 32a,...32e in the left hand shroud 20, and a different liquid to all of the nozzles 32a,...32e in the right hand shroud 20.
- a number of vertical or horizontal layers may be generated by supplying different liquids to different nozzles and adjusting the nozzle direction.
- the degree of separation of the different liquids between the layers will depend on the amount of overspray from one nozzle to the other and to the shape of the cloud generated by the nozzle. However, these factors may be adjusted by suitable manipulation of the nozzle position, the velocity of air delivered by the fan and the volume of liquid dispensed.
Landscapes
- Catching Or Destruction (AREA)
- Electrostatic Spraying Apparatus (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US30543881A | 1981-09-25 | 1981-09-25 | |
US305438 | 1981-09-25 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0076121A2 true EP0076121A2 (fr) | 1983-04-06 |
EP0076121A3 EP0076121A3 (en) | 1984-01-11 |
EP0076121B1 EP0076121B1 (fr) | 1986-05-28 |
Family
ID=23180782
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19820305056 Expired EP0076121B1 (fr) | 1981-09-25 | 1982-09-24 | Procédé et appareil pour la pulvérisation électrostatique de plusieurs liquides |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0076121B1 (fr) |
CA (1) | CA1179903A (fr) |
DE (1) | DE3271394D1 (fr) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE959236C (de) * | 1952-12-04 | 1957-02-28 | R Sigvardt As | Geblaesegehaeuse fuer eine Vorrichtung zum Verspruehen eines Insektenvertilgungsmittels |
FR2342796A1 (fr) * | 1976-03-05 | 1977-09-30 | Research Corp | Pulverisation electrostatique a charge d'espace reglee |
FR2416737A1 (fr) * | 1978-02-08 | 1979-09-07 | Loiseau Ets | Appareil pour le traitement de cultures par pulverisation d'un liquide |
-
1982
- 1982-09-21 CA CA000412896A patent/CA1179903A/fr not_active Expired
- 1982-09-24 EP EP19820305056 patent/EP0076121B1/fr not_active Expired
- 1982-09-24 DE DE8282305056T patent/DE3271394D1/de not_active Expired
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE959236C (de) * | 1952-12-04 | 1957-02-28 | R Sigvardt As | Geblaesegehaeuse fuer eine Vorrichtung zum Verspruehen eines Insektenvertilgungsmittels |
FR2342796A1 (fr) * | 1976-03-05 | 1977-09-30 | Research Corp | Pulverisation electrostatique a charge d'espace reglee |
FR2416737A1 (fr) * | 1978-02-08 | 1979-09-07 | Loiseau Ets | Appareil pour le traitement de cultures par pulverisation d'un liquide |
Also Published As
Publication number | Publication date |
---|---|
CA1179903A (fr) | 1984-12-27 |
EP0076121B1 (fr) | 1986-05-28 |
DE3271394D1 (en) | 1986-07-03 |
EP0076121A3 (en) | 1984-01-11 |
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