JPS6393364A - Electrostatic spray head - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic spray head for inductive charging of four-electrolic liquids.

[Conventional technology and problems]

The use of electrostatic forces applied industrially to solid and liquid surface coatings has been known for over 40 years. When early attempts were made to utilize this technology for agricultural hazardous substance control, the operational demands encountered were markedly different from those found in industry due to a long lack of success, and the basic The charge transfer method was also poorly understood.

This lack of knowledge was remedied during the 1960's by research conducted by North Carolina State University on the activation phenomena that occur during the application of charged particles to plants.

During this period of time, further industrial research and development has focused on reliable electrostatic spray processing and typical machinery, particularly machines suitable for harsh applications in crop feeding and hazardous material control, that are both economical and environmentally friendly. It helped motivate me.

The use of electrostatic forces to augment the effects of gravity and inertia in the control of finely divided elements has long been recognized. The scientific basis for this effect is given by Felici (1965).
pointed out by. He demonstrated mathematically that under a given electrolytic field, the ratio of charge to a particle per unit mass varies inversely to the diameter of the particle. Fe
Lici also established that the motion of particles depends on the ratio of electrostatic force and gravitational force, which is also inversely proportional. Utilizing electrostatics to improve spray delivery and precipitation solves traditional problems encountered with droplets smaller than 100 μm.

Two physical conditions are met in order to be able to use electrostatic forces for spraying. These conditions are, firstly, that each droplet must be endowed with a sufficient net charge, and secondly that the charged droplet must be acted upon by an electric field.

The charge required for droplets with a diameter of 50 μm is typically between 0.5 and 1.5×10′. The electromagnetic field may be self-excited or may be provided by other adjacent charged objects such as metal electrodes or other charged droplets.

In the development of reliable droplet charging systems for crop spray applications, there are three areas of proven methods for imparting the necessary charge to insecticide spray droplets. These are: 1. Ionized field droplet charging for charging both conductive and non-conductive liquids; 2. Charging and direct electrostatic atomization of non-conductive liquids; 3. Electrostatic induction droplet charging of conductive liquids. Each of the three charging methods has its own advantages and disadvantages, but all are used complementary.

[Object and outline of the invention]

However, electrostatic induction is a very satisfactory method for agricultural charge spray droplets, and it is an object of the present invention to provide an electrostatic spray head for carrying out this method.

In the electrostatic induction method, direct charge transfer of a liquid jet to the droplet generation zone is by electrostatic induction of a continuous jet of electrons. This is to maintain it at ground potential in the presence of a nearby positive induction electrode. The surface density of free electrons is typically on the order of 10"/cIII. Each droplet formed from the surface of a negatively charged jet has a droplet formation zone acting between the non-ionizing electrode and the jet. As long as it is subjected to an induced electrostatic field, a net negative charge can be released.The GauSS law states that the maximum droplet charging should occur in the droplet generation zone located at the region of the jet end surface that gives the maximum different intensity. The process is completely reversible for polarity.

The level of droplet charge imparted by electrostatic induction depends on the time the charge is transferred to the droplet generation zone relative to the time required for droplet generation. The ability to conduct charge transfer through a liquid emanating from a grounded metal nozzle is due to the electrical properties of the liquid forming a continuous jet. For insecticides, this liquid property is specified by the charge transfer time constant, which must be smaller than the droplet formation time in order to be sufficiently charged by this induction process.

Spray liquids with a resistance of less than 106 ohms/meter are static M, F.
It must be sufficiently charged by 's guidance.

For water-based sprays the charge transfer limit is 10'
It is encountered at a resistivity of 1/m or more. In contrast, for oil-based sprays, 106 ohms/
Encounter resistivity greater than that of rice.

According to a principal aspect of the invention, a spray head for propelling a spray of inductively charged droplets includes an electrically non-conducting spray head formed for separably connecting at its rear end to a liquid supply pipe. a main body, and a rear end protruding from the rear end of said main body for connecting to a liquid-tight connection to the liquid supply at the rear end, and a rear end of said main body at the front thereof; a non-conductive spray tube projecting beyond the front surface and containing a mixture of a nozzle and a filter made of a metallic material; and a non-conductive spray tube separably secured to the front surface of the main body, enclosing the nozzle concentrically and extending forward from the nozzle. an annular metal foam electrode mounted on the front part of the main body and surrounding the rear of the nozzle and the induction electrode assembly, with a central open metal foam electrode located at its rear end and in the path of the spray emanating from said nozzle front end; an inductive electrode assembly having a counter electrode;
The counter electrode is maintained at an opposite polarity to the guiding electrode to minimize spray drift and prevent spray particles from clogging the spray head.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

The illustrated electrostatic spray head mainly has three parts: a main body 1, a spray tube 2 and an induction electrode assembly 1.
2 (Figure 2).

The main body l is made of a non-conductive material and is bell-shaped with a vertical cylindrical cross-section 15 which cooperates with the recess 22 to hold a sealing ring (not shown).

This cross-section is designed to fit directly into a standard connector (not shown) for non-conductive pipe.

At the top of the main body 1 there is another recess 23 (FIG. 1) for locating the tip 24 in the spray tube 2. The main body 1 also has a counter electrode 5 (FIG. 2), which is a metal disc designed to snap in and out of the main body relatively easily. The electrostatic potential to the counterelectrode 5 is applied through a metal insert 6, which has a diamond-shaped cross section giving it stiffness to counter the bending forces acting on it. The end 25 of the insert 6 is in direct contact with the electrode 5 with the tip bent to maintain contact. The other end of the insert 6 is designed to accept a standard spade connector for easy opening and reconnection.

The spray tube 2 has a cross member or tip 2 at its head.
It is a rigid tube made of a non-conductive material with a thickness of 4. This cross member 24 is located in a recess 23 in the top of the main body 1, and the two parts are held in position by a standard vibe connector. The other end of the tube 2 is equipped with a metal nozzle 3 which cooperates with a filter fitted to the end of the tube. There are two diametrically opposed flat surfaces on the outside of the nozzle to facilitate separation of the nozzle and filter from the tube. A nozzle cap 4 made of a non-conductive material is provided to prevent the metal surface of the nozzle from being exposed to induced electrostatic fields.

The dielectric pole assembly 12 consists of a non-conductive hollow cylindrical case 16 having an outer diameter equal to the width of the central section 17 of the lower end of the main body 1. One end of the case is embedded in a metal ring 9 having inner and outer threads, and the main body 1
It is combined with another electrode ring 8 embedded in the electrode ring 8 by means of a wire.

The other end of the cylindrical case 16 is cut at 18 and ends in four symmetrical protrusions 13 which engage the convex rear surface of the induction electrode 11 made from a metal foam several inches thick. The side of the electrode 11 is concave and has four protrusions or corners 1.
9 which extend laterally beyond the wall of the case 16 when the electrodes are secured at one end of the case by four metal inserts 10. One end of each insert 10 fits into an opening 20 (FIG. 4) in metal ring 9, and the other end is soldered to opening 21 in inductive electrode 11. Electrostatic potential is insert 7,
Inductive electrode 1 via ring 8.9 and insert IO
1. Both the ring 8 and the metal insert 7 are embedded in the main body 1.

In operation, spray liquid, maintained at ground or earth potential, is supplied to the spray head via the spray tube 2 from a pressure source. A film of liquid several fins in diameter and length is produced at the nozzle orifice 26, which is broken into droplets to produce a spray. The induction electrode 11 is placed concentrically with the liquid film generated from the nozzle, and is separated into several parts 1, such that the water droplet generation zone is within the width of the induction electrode to maximize charge transfer. It has become. A positive potential (2-6) kV is applied to the inductive electrode 11 while the liquid film is kept at ground potential, and a negative potential is applied to the spray droplets by induction.

Due to the high specific charge, some of the small droplets are attracted towards the induction electrode 11.

This is an inherent drawback of the inductive charging method.

However, the purpose of using a metal foam electrode is to absorb the liquid that impinges on it by capillary action. Due to the metallic structure of the gold-flexed foam electrode, a dynamic equilibrium is finally reached, and less liquid is trapped on the protrusion. These liquid films at the protrusions are acted upon by a dense electrostatic field due to the creation of a Taylor cone that breaks up into positively charged droplets.

The induction electrode area is optimized for minimal collection of fine spray. Furthermore, if there is an induced electrode voltage (reverse polarity), T
Strengthens the electrostatic field at the top of the aylor cone and aids in the bursting process.

The amount of secondary droplets sprayed from the protrusion is small compared to the main spray. In this way, it is also possible to send an auxiliary gas through the channel 14 of the main body 1 and diffuse it through the induction electrode 11 to repel and cover the fine spray. Although the potential applied to the induction electrode and the geometrical position are not unique, any changes that may be made thereto must avoid the generation of corona in the system.

The counter electrode 5 is maintained at a negative potential (-2 to -6) kV to prevent the generated local electrostatic fields from fouling the spray and to minimize spray drift.

The polarity of both TL poles can be reversed if necessary. Below, ;; white

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an electrostatic spray head according to the present invention;
2 is a longitudinal cross-sectional view of the spray head of FIG. 1, FIG. 3 is an exploded cross-sectional view of the spray tube assembly, FIG. 4 is a perspective view of the case of the induction electrode assembly, FIG. 5, FIG. 6, and FIG. 7 is a perspective view, a plan view, and a cross-sectional view of the induction electrode, and FIG. 8 is a cross-sectional view taken along the line ■-■ in FIG. 6. 1... Main body, 2... Spray tube, 3...
Nozzle, 4... Nozzle gear, 5... Counter electrode, 6.7.10... Metal insert, 11... Metal foam electrode, 12... Inductive electrode assembly, 26... Nozzle orifice. The following is an engraving of the blank drawings (no changes to the content) Procedural amendment (method) July 8, 1985 Director General of the Patent Office Kunio Ogawa Patent side 2 submitted on June 24, 1986, name of the invention Electrostatic Spray Head 3, Relationship with the person making the amendment Patent applicant name: Firminde Limited 4, Agent address: October 6, Toranomon-8-chome, Minato-ku, Tokyo, 105
7. Description subject to amendment 7. Engraving of the description of the content of the amendment (no change in content) 8. Engraving of the specification of the attached documents 1 written procedural amendment (voluntary) July 8, 1985 Kuni Ogawa, Commissioner of the Japan Patent Office Husband Patent filed on June 24, 1986 2, Name of the invention Electrostatic Spray Head 3, Relationship to the case by the person making the amendment Patent applicant name Firmin Dep Limited 4, Agent address 105 Toranomon, Minato-ku, Tokyo -Chome 8-10-5,
Subject of amendment (11 "Claims" column (2) of the specification, "Detailed description of the invention" column 6, contents of amendment (1) Claims of the specification as shown in the attached sheet) (2) The detailed explanation column of the invention of Akira Iut is amended as follows. (a) Akira: SS page 9, line 1 r According to the main aspects of the present invention, page 10 The first line [Characteristic. Up to J are corrected as follows. rAccording to a main aspect of the invention, an electrostatic spray head for propelling a spray of inductively charged droplets, comprising:
an electrically non-conductive main body for connection to a liquid supply; and a spray tube having a nozzle of conductive material extending through the main body and projecting from the front of the main body at a forward end for connection to the liquid supply. and a non-conductive housing concentrically enclosing the nozzle and extending forward from the nozzle, secured to the front surface of the main body, the front end of which is located at a distance from the front end of the nozzle in the path of the spray emanating therefrom. The invention is characterized by having an induction electrode assembly having a concentric metal foam electrode and a concentric counter electrode mounted in front of the main body and surrounding the rear of the nozzle and the induction electrode assembly. J7, List of Attachments Claims 1, 2, Claim 1, An electrostatic spray head for propelling a spray of inductively charged droplets, the head comprising an electrostatic spray head for propelling a spray of inductively charged droplets, the head comprising: a spray tube having a nozzle of conductive material passing through the main body and having a nozzle of conductive material projecting from the front of the main body at a forward end for connection to the liquid supply; secured to the front surface of the main body in a non-conductive housing extending forward from the nozzle;
a concentric metal foam electrode located at its forward end and in the path of the spray emanating from said nozzle front end, and a concentric counter electrode mounted forward of said main body and surrounding the rear of the nozzle and the induction electrode assembly; An electrostatic spray head 2 characterized in that it has an inductive electrode assembly, said main body having a screw threaded metal ring cooperating with a similar ring at the rear end of said housing to secure the housing of said main body at its front end. Spray head 3o according to claim 1, characterized in that the electrode extends longitudinally from a metal ring soldered to the front end of the electrode through the wall of the housing. Spray head 4 according to claim 2, characterized in that the spray head 4 is secured to the housing by an insert, the electrode passing from the rear end of the main body through the metal insert, the metal ring and the cylindrical part. A spray head (5) according to claim 3, characterized in that the spray head (5) is adapted to be connected to a source of electrical potential through a metal conductor passing behind, said electrode being of arcuate cross section and the convex surface of said electrode being of arcuate cross section. 6. A spray head according to claim 3 or claim 4, wherein the spray head 6 is secured in a position that engages with the front end of the housing, the front end of the housing engages with the concave surface of the electrode, and 6. A spray head according to claim 5, characterized in that said electrode has four concave edges, said electrode having four concave edges, said concave edges having four concave edges; But in the meantime,
Spray head 8 according to any of the patents, characterized in that the outer side of the wall of the housing defines a projection which projects laterally when the electrode is secured in its position, said counter electrode Spray head 9 according to any of the preceding claims, characterized in that it is a metal disc snapped-fitted to the front end of the body, the counter electrode passing longitudinally through the body and the electrical potential source The spray head 10 according to any one of the preceding claims, characterized in that the spray head 10 engages with one end of a metal contact member protruding from the rear end of the main body to the other end in order to be able to connect to the nozzle in a minute. Spray head 11 according to any of the preceding claims, characterized in that the spray head 11 is adapted to a cap of non-conductive material 1'1 to prevent the exposed surface of the spray head from being exposed to induced electrostatic fields, characterized in that said main body has a longitudinally extending passageway for connecting said interior of said housing to an auxiliary supply of gas which diffuses it through said scrapers to dispel fine spray; Patent layhead procedure amendment (method) % formula % l. Display of the case 1986 patent wIM No. 155608 2, Name of the invention Electrostatic Spray Henodo 3, Person making the amendment Relationship to the case Patent applicant name Firmindepri Limited 4, Agent address 105 Toranomon, Minato-ku, Tokyo Chome 8 Lo No. 6,
Subject of amendment +11 "Applicant's representative" column of application (2) Power of attorney (3) Specification (4) Drawing 7, Contents of amendment (1) f2) As attached (4) Engraving of drawing ( (No change in content) However, regarding (3), we have already submitted it in the procedural amendment (method) dated July 8, 1988. 8. Attached document list file correction application 1 copy (2) Power of attorney and translation 1 copy each (3
) 1 engraving drawing

Claims (1)

Claims: 1. An electrostatic spray head for propelling a spray of inductively charged droplets, comprising: an electrically non-conducting main body for connection to a liquid supply; and said liquid supply. a spray tube passing through the main body and having a nozzle of conductive material protruding from the front of the main body at its front end for connection to the main body; and a non-conductive housing concentrically enclosing the nozzle and extending forward from the nozzle. secured at the front of the main body;
a concentric metal foam electrode located at its forward end and in the path of the spray emanating from said nozzle front end, and a concentric counter electrode mounted forward of said main body and surrounding the rear of the nozzle and induction electrode assembly; An electrostatic spray head 2 characterized in that it has an inductive electrode assembly, said main body having a screw threaded metal ring cooperating with a similar ring at the rear end of said housing to secure the housing of said main body at its front end. Spray head 3 according to claim 1, characterized in that said electrode extends longitudinally from a metal ring soldered thereon at its front end through the wall of the housing. Spray head 4 according to claim 2, characterized in that the spray head 4 is secured to the housing by a metal insert, the electrode passing through the metal insert, the metal ring and the cylindrical part to the rear end of the main body. Claim 3 adapted to be connected to a source of electrical potential through a metal conductor passing rearward from the
The spray head 5 according to claim 3, wherein the electrode has an arcuate cross section, and the convex surface thereof is secured at a position where it engages with the front end of the housing. 6. The front end of the housing is cut to leave a symmetrically disposed protrusion that engages a concave surface of the electrode and provides a passage for the metal insert. spray head 7, said electrode having four concave edges between which:
Spray head 8 according to any of the preceding claims, characterized in that the outer side of the wall of the housing defines a projection which projects laterally when the electrode is secured in its position, said opposing Spray head 9 according to any of the preceding claims, characterized in that the electrode is a metal disk snap-fitted to the front end of the main body, the counter electrode passing longitudinally through the body, A spray head 10 according to any of the preceding claims, characterized in that the spray head 10 engages one end of a metal contact member projecting from the rear end of the main body to the other end for releasably connecting to a potential source. Spray head 11 according to any of the preceding claims, characterized in that the nozzle is adapted to a cap of non-conducting material to prevent the metal surface from being exposed to induced electrostatic fields. said body having a longitudinally extending passageway for connecting the interior of said housing to an auxiliary supply of gas which diffuses through said electrode to dispel fine spray thereon; Spray head according to any of the claims