Electrostatic spray drying nozzle assembly

Abstract

An electrostatic sprayer (10, 70) capable of operating at high flow rates and low pressures, particularly suitable for spray drying. The sprayer (10, 70) includes an elongated body (12) having a downstream spray nozzle assembly (14, 71) through which electrically charged liquid is directed via a central feed tube (18) within the nozzle body (12) and atomizing air is supplied via an annular passageway (25) around the liquid feed tube (18). In one embodiment, the nozzle assembly is an external mix cluster spray nozzle assembly (14) having a plurality of circumferentially spaced metallic spray tips (40). In another embodiment, the spray nozzle is an internal mix nozzle assembly (71) having a spray tip (71) with an internal mixing chamber (72a) for atomizing the liquid prior to discharge.

Description

[0001] Cross-references to related applications This patent application claims the benefit of U.S. Patent Application No. 62 / 773,875, filed November 30, 2018, which is incorporated herein by reference. Technical Field

[0002] The present invention generally relates to liquid spray nozzle assemblies, and more particularly, to electrostatic spray nozzle assemblies particularly suitable for spraying dry liquids by electrostatically charging the fluid to promote the decomposition and distribution of fine liquid particles. Background Technology

[0003] In the spray drying industry, electrostatic spray nozzle assemblies are now used to improve drying efficiency and product quality. While the use of internal components made of non-metallic materials is desirable, the solvents used in many spray drying applications corrode and degrade such materials. Therefore, it is essential that spray dryer equipment be designed to ensure that the solvent in its liquid state does not come into contact with such degradable plastic components. Typically, electrostatic spray dryers utilize external mixing spray nozzle assemblies, where the liquid supply and atomizing gas interact outside the nozzle.

[0004] However, external mixing spray nozzles operate at very low liquid flow rates, such as feed feeds less than 10 kg / hr. These low-flow nozzles produce very fine droplets at easily controllable low pressures. However, to increase the flow rate, increasing the diameter of the nozzle's liquid discharge orifice is necessary. However, as the diameter of the liquid discharge orifice increases to achieve higher flow rates, the droplet size of the spray also increases. If the droplet size is too large, the droplet will not be adequately dried in the dryer chamber (even when electrostatically charged). Inadequately dried liquid droplets can coat the internal components of the sprayer, hindering optimal operation and requiring cleaning and / or replacement. Larger spray nozzle discharge orifices also result in the spray being emitted at greater velocities and momentum. In spray drying applications, this requires longer and more expensive drying chambers to accommodate such emitted sprays. To improve spray capacity while maintaining optimal liquid atomization at low flow rates, it is necessary to use a variety of electrostatic sprayers with multiple nozzle bodies, supply lines, compressed gas lines, pumps, and high-voltage cables, which is expensive and can be cumbersome in terms of installation and use.

[0005] Internally mixed spray nozzle assemblies are known, offering the benefit of multi-stage liquid decomposition during atomization, which allows the nozzle to produce very fine liquid particles. However, internally mixed spray nozzles operate at higher liquid pressures, which precludes the use of peristaltic pumps operating at low pressures, particularly preferred for spray drying in the pharmaceutical and fragrance industries. Internally mixed spray nozzles also utilize a relatively small amount of compressed atomizing gas, which is advantageous when atomizing non-air gases such as hydrogen, desirable in various spray drying applications. Summary of the Invention

[0006] The purpose of this invention is to provide an electrostatic sprayer with an electrostatic spray nozzle assembly that can generate a controllable fine liquid droplet spray with a relatively high flow rate, which is particularly advantageous for spray drying applications.

[0007] Another objective is to provide an externally mixed electrostatic spray nozzle assembly as described above, which can operate at a relatively high flow rate in a spray dryer having a shorter and more compact drying chamber.

[0008] Another objective is to provide an electrostatic spray nozzle assembly of the aforementioned type, wherein the internal biodegradable plastic or other non-metallic components of the spray nozzle assembly are isolated from the sprayed liquid.

[0009] Another objective is to provide an electrostatic sprayer having the above-mentioned type of spray nozzle assembly, which can operate at relatively low pressure and thus can economically utilize a low-pressure peristaltic pump.

[0010] Another objective is to provide an electrostatic spray nozzle assembly of the above type, having an internal mixing spray nozzle for more effectively generating controllable fine liquid droplets at a lower atomizing gas flow rate, which is particularly beneficial for spray drying.

[0011] Another objective is to provide an electrostatic spray nozzle assembly for use in spray drying that is relatively simple in structure and conducive to economical manufacturing. Attached Figure Description

[0012] Other objects and advantages of the present invention will become apparent when reading the following detailed description and referring to the accompanying drawings, wherein: Figure 1 A longitudinal cross-sectional view of an illustrative electrostatic sprayer with an external mixing spray nozzle assembly according to the present invention; Figure 2 for Figure 1 The image shows an enlarged, incomplete cross-sectional view of the external mixing spray nozzle assembly of the electrostatic sprayer. Figure 3 for Figure 2 An enlarged, incomplete cross-sectional view of one of the spray tip assemblies of the spray nozzle assembly shown in the figure; Figure 4 for Figure 1 and Figure 2 An exploded view of the spray nozzle assembly shown in the figure; Figure 5 To depict Figure 1 The image shows a longitudinal cross-sectional view of the assembled spray nozzle assembly in an electrostatic sprayer. Figure 6 A longitudinal cross-sectional view of another embodiment of the electrostatic sprayer according to the present invention, in which the electrostatic sprayer has an internal mixing spray nozzle assembly; Figure 7 for Figure 6 The image shows an enlarged, incomplete cross-sectional view of the spray nozzle assembly of the sprayer. Figure 8 For similar Figure 6 The longitudinal cross-sectional view shows the components of the assembled sprayer; Figure 9 for Figure 6 An exploded view of the internal mixing spray nozzle assembly of the electrostatic sprayer is shown in the figure; and Figure 10 To show Figure 6 The image shows an enlarged, incomplete perspective view and partial cross-sectional view of the discharge end of the electrostatic sprayer.

[0013] While the invention allows for various modifications and alternative structures, certain illustrative embodiments are shown in the accompanying drawings and will be described in detail below. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed, but rather, on the contrary, it is intended to cover all modifications, alternative structures, and equivalents falling within the spirit and scope of the invention. Detailed Implementation

[0014] Now refer more specifically to the attached diagram. Figure 1An illustrative electrostatic sprayer 10 according to the present invention is shown. The illustrated electrostatic sprayer 10 includes a fluid and high-pressure inlet head 11, an elongated nozzle tube or body 12 extending downstream from the inlet head 11, and an outlet spray nozzle assembly 14 at the downstream end of the elongated nozzle body 12. It will be understood that the electrostatic sprayer 10 can be used in spray drying systems, such as the spray drying system disclosed in U.S. Application No. 15 / 342,710, filed November 3, 2016, assigned to the same assignee as this application, the disclosure of which is incorporated herein by reference. The nozzle body 12 may be relatively long in length relative to its diameter for mounting the sprayer 10 in the wall of a processing vessel, etc., wherein the outlet spray nozzle assembly 14 is inside the vessel, while the inlet head 11 is remotely positioned outside the vessel. The input head 11 and nozzle body 12 are preferably made of hard plastic or other non-conductive material, such as thermoplastic polyetherimide (PEI) sold under the trademark Ultem 1000, which can be machined into its final shape. In practice, the elongated nozzle body 12 may have a length that is 10 times or more the diameter of the nozzle body 12 (up to 12 inches or more).

[0015] The input head 11 is cylindrical in shape, and the elongated body 12 is a cylindrical body component 15. The cylindrical body component 15 has an upstream end that can be through-engaged in a threaded opening in the input housing (hub) 11, wherein a sealing O-ring 16 is inserted between the cylindrical body component 15 and the input head 11. A liquid supply tube 18, made of stainless steel or other conductive material, extends axially through the outer cylindrical body component 15, wherein the upstream end 18... a It is supported therein and extends outward therein for connection to the pressurized liquid supply device 19. In this case, the liquid supply pipe 18 has an upstream end section 18 with a reduced diameter. b Its positioning shoulder 18 is limited to be installed in the countersunk hole of the input head 11. c A sealing O-ring 17 is inserted between the liquid supply pipe 18 and the inlet head 11.

[0016] A liquid supply tube 18 extends axially through the cylindrical body component 14 to define an annular atomizing gas passage 25 between the liquid supply tube 18 and the outer cylindrical body component 15. An input head 11 has a radial pressurized gas inlet passage 26 that receives a gas inlet filler 28 connected to a suitable pressurized gas supply device 29. The gas inlet passage 26 communicates with an annular gas chamber 30 surrounding the liquid supply tube 18 within the input head 11, and the annular gas chamber 30 in turn communicates with the annular atomizing gas passage 25 passing through the cylindrical body component 15.

[0017] To charge the liquid that is guided into and passes through the liquid supply pipe 18, the input head 11 also has a radial passage 31 (upstream of the gas inlet passage 26 in this case), which receives a fitting 32 secured to a high-voltage cable 34 connected to a high-voltage power source. In this case, the high-voltage cable 34 has a terminal adjacent segment 35 biased by a spring 36 to ensure reliable electrical conductivity with the liquid supply pipe 18. With the liquid supply pipe 18 electrically charged by the high-voltage cable 34, it can be seen that the supply liquid passing through the supply pipe 18 is charged along its entire travel length to the spray nozzle assembly 14. Simultaneously, pressurized gas is conveyed through an annular gas passage 25 between the liquid supply pipe 18 and the outer cylindrical body component 15.

[0018] According to this embodiment of the invention, the spray nozzle assembly 14 is an externally mixed spray nozzle assembly capable of operating at relatively high liquid flow rates and low pressures to produce a fine spray of liquid particles (particularly suitable for spray drying applications) for optimal and economical spray drying operation. For this purpose, the spray nozzle assembly 14 has a cluster head design comprising multiple independent spray tips 40 connected to a common pressurized liquid and gas supply device (in this case, from the liquid supply line 18 and the annular pressurized gas passage 25, respectively). The cluster head spray nozzle assembly 14 is shown (e.g., Figure 2-4 (Best depicted in the image) A nozzle head body 39 is provided, comprising a nozzle liquid manifold 41 and a nozzle cap 45. The nozzle liquid manifold 41 forms a plurality of outwardly angled liquid passages 42, each communicating between a common liquid supply pipe 18 and a plurality of corresponding downstream spray tip receiving openings 44, wherein corresponding spray tips 40 are mounted and held within the plurality of corresponding downstream spray tip receiving openings 44. Figure 2 and Figure 4 A nozzle cap 45, mounted on the downstream end of the nozzle liquid manifold 41, has a plurality of circumferentially spaced cylindrical openings 46 aligned with the spray tip 40. In this case, the nozzle liquid manifold 41 has a truncated conical upstream end 41 that extends outward in the downstream direction. a and the outwardly curved downstream end 41 b The spray tip receiving opening 44 extends outward in the downstream direction at a small angle (such as between approximately 12 and 15 degrees) relative to the central axis of the nozzle liquid manifold 41 and the cylindrical body component 15 through the outwardly curved downstream end 41. b .

[0019] In implementing this embodiment, the spray tip 40 is made of free conductive metal, and in this case, it has an upstream cylindrical sleeve 40. a The section that gradually narrows inward and extends forward is 40. b(having an outwardly extending radial flange 40 adjacent to its downstream end) c ), and a relatively small-diameter nose extending forward 40 d ( Figure 4 Each spray tip 40 has an upstream smaller diameter annular sleeve 40 positioned in the spray tip receiving opening 44 of the nozzle liquid manifold 41. e The sealing O-ring 48 is inserted into the upstream smaller diameter annular sleeve 40. e Between and the spray tip receiving opening 44 ( Figure 2 Each spray tip 40 has a relatively large diameter inlet passage section 49, which converges inwardly into a conical passage section 49. a Connecting, inwardly converging conical passageway section 49 a Then, extending through the nose 40 d Relatively small diameter liquid passages 49 b Connect, nose 40 d Limited to a relatively small discharge orifice 49 c Such as approximately 0.040 inches ( Figure 3 Each of the spray tip inlet passage sections 49 at the spray tip is connected to a corresponding one of the outward converging liquid flow passages 42 in the nozzle liquid manifold 41.

[0020] 40 radial flanges at each spray tip 49 c Each is installed in a corresponding one of the cylindrical openings 46 of the nozzle cap 45, wherein the annular plastic air cap 50 has a radial flange 49. c The insertion seal between the nozzle cap opening 46 and the radial flange 49 around the spray tip is used to seal the nozzle cap opening 46. c Setup. In this case, the plastic air cap 50 has an L-shaped cross-sectional perimeter that surrounds the radial flange 40 at the tip of each spray nozzle. c The front and outer perimeters are set, with the lip extending forward 50. a Installed with respect to the overlapping relationship of the annular lip with respect to the nozzle cap opening 46. Figure 3 The nozzle cap 45 is secured to the nozzle liquid manifold 41 by a nylon or similar non-metallic retaining screw 52, ​​which extends centrally through the nozzle cap 45 and into the axial opening 41 of the nozzle liquid manifold 41. a The spray tip 40 and the plastic air cap 50 are threaded together to secure the spray tip 40 and the plastic air cap 50 in an assembly relationship.

[0021] To atomize the liquid discharged from the spray tip 40, the nozzle liquid manifold 41 and the nozzle cap 45 define an annular atomizing gas passage 55. Figure 2The annular atomizing gas passage 55 communicates with the annular gas passage 25 located between the metal liquid supply pipe 18 and the external nozzle body component 15, and the annular gas passage 56 surrounding each spray tip 40, via a corresponding right-angle inlet passage 58. Pressurized atomizing gas can thus be simultaneously guided around multiple spray tips 40, passing through the corresponding spray tip radial flange 40. b Circumferential air passage opening 40 d And outward along the axial direction from multiple spray tip discharge orifices 49 c The emitted liquids form interacting atomized bonds ( Figure 3 ).

[0022] In another feature of this embodiment, the liquid guided through the cluster spray nozzle assembly 14 undergoes multi-stage electrostatic charging to enhance liquid atomization upon discharge from the spray nozzle assembly. For this purpose, the downstream end of the electrically charged liquid supply pipe 18 has a sharp chamfered end 60 (preferably charged to approximately 30 kV). This sharp chamfered end 60 first focuses the electrostatic field onto the supplied material as it is discharged from the supply pipe 18 and before entering the spray tip 40. Furthermore, the gap between the sharp chamfered end 60 of the charged liquid supply pipe 18 and the spray tip 40 creates a capacitance within the gap, which unexpectedly increases the electrostatic charge on the liquid as it is guided to and through the spray tip 40.

[0023] In operation, the cluster-head spray nozzle assembly 14 has proven to produce a fine spray of liquid particles best suited for spray drying applications at relatively high liquid flow rates up to 125 kg / hr. However, each of the spray tips 40 has a relatively small discharge orifice 49. c This allows for low-pressure, controlled operation using peristaltic pumps advantageous in spray drying applications. Furthermore, the cluster-head spray nozzle assembly 14 can deliver such high flow rates of spray over much shorter lengths (e.g., three to five feet), and therefore, it is possible to increase the flow rate using spray nozzles with larger discharge orifices and liquid pressures in a more economical spray drying chamber than has been the case to date. It has also been found that multiple electrostatically charged spray patterns emitted from the cluster-head spray nozzle assembly within the same chamber cause particles to reattach to each other after they dry, thereby reducing the number of particles that are too fine to be controlled and can hinder coating efficiency. Finally, it can be seen that all internal components of the electrostatic sprayer subjected to contact with the sprayed liquid are made of Teflon or stainless steel, which is resistant to most of the liquids to be sprayed. The outer cylindrical body component 15 remains non-contact with the liquid supply material and is preferably made of a harder polyetherimide material that can be degraded by some solvents used in spray drying.

[0024] To facilitate the economical manufacture of the electrostatic sprayer 10, it will be recognized that the cluster spray nozzle assembly 14 can be pre-assembled for efficient installation within the nozzle body 12. In this case, the pre-assembled spray nozzle assembly 14 can be assembled within the cylindrical body component 15 by positioning it from its upstream end, as shown below. Figure 5 The cylindrical body component 15 shown is depicted with an annular lip 59 of smaller diameter at its downstream end, which supports another periphery of the nozzle cap 45 by means of a sealing O-ring 63 between the nozzle cap 45 and the cylindrical body component 15. The liquid supply tube 18 can thus be inserted into the central opening 61 of the nozzle liquid manifold 41, with the inserted annular O-ring 62 between the liquid supply tube 18 and the central opening 61. Although the spray nozzle assembly 14 shown has six spray tips, other numbers of spray tips may be used depending on the size of the nozzle liquid manifold, preferably between approximately three and eight.

[0025] Now refer to more specifically Figure 6-10 The diagram illustrates an electrostatic sprayer 70 having an alternative embodiment of the electrostatic spray nozzle assembly 71 according to the invention, wherein parts (similar to those described above) are given similar reference numerals. The electrostatic sprayer 70 includes an input head 11 having a liquid supply tube 18, a pressurized gas inlet 26, and a high-voltage cable connection 34 similar to those described above. The sprayer 70 also includes an elongated nozzle body 12 fixed to the input head 11, wherein the electrically rechargeable liquid supply tube 18 is centrally disposed within the input head 11.

[0026] In this embodiment of the invention, the electrostatic spray nozzle assembly 71 is an internally mixed spray nozzle assembly capable of guiding a fine spray of liquid particles for optimal use in spray drying. The illustrated spray nozzle assembly 71 essentially includes a dome-shaped spray tip 72, an internal air guide 74 mounted directly upstream of the spray tip 72, and a center positioner 75 for centrally supporting the downstream end of the liquid supply pipe 18 within the air guide 74 and the spray tip 72.

[0027] The dome-shaped spray tip 71 shown has an inwardly converging mixing chamber 72. a The connected upstream cylindrical passage section 72, and the inwardly converging mixing chamber 72 a Then by limiting the spray discharge orifice 72 c Smaller diameter cylindrical passage section 72 bThe nozzle tip 71 is connected. The nozzle tip 71 has an outwardly extending radial flange 74, which supports a reduced-diameter annular retaining lip 75 abutting against the outer cylindrical nozzle body component 18. A sealing O-ring 76 is inserted between the dome of the nozzle tip 71 and the inner annular side of the retaining lip 75 of the cylindrical body component 15.

[0028] The air guide 74 has an outer cylindrical wall section 74 installed within the cylindrical body component 15. a and an annular sleeve 74 concentrically mounted within the annular countersunk hole at the spray tip 71, extending forward. b The center locator 75 has a center opening 75. a The liquid supply pipe 15 has a central opening of 75 degrees. a Extending and supported by multiple radial support legs 75 b In this case, the radial leg is 75 degrees. b In the cylindrical wall 74 of the air guide 74 a The air guide 74 is supported near its downstream end. The air guide 74 has an inwardly curved inner wall 74. c It is used to guide and converge pressurized atomized gas from the annular gas passage 25 through the small annular gas passage 78 surrounding the liquid supply pipe 18.

[0029] In a further embodiment, the liquid supply pipe 18 includes an end segment section 18 axially connected thereto. a 18 end segments a A liquid passage section 80 with a reduced diameter is formed, which communicates with a plurality of transverse grooves 81 to guide the pressurized liquid flow from the liquid supply pipe 18 radially outward, so as to guide the pressurized atomizing gas through the narrow annular air passage 78 directly across the transverse grooves 81 for interaction and atomization. In this case, there are four circumferentially spaced transverse grooves 81 in the supply pipe section 18. a An impact surface 82 is defined at the end of the liquid supply pipe 18, guiding the liquid passing through the liquid supply pipe 18 to impact the liquid against the impact surface 82 and forcefully guide it radially outward for interaction with the pressurized atomizing gas. It will be understood that the extension segment 18 of the liquid supply pipe 18... a It is also made of conductive metal material and is fixed in electrical contact with the liquid supply pipe 18.

[0030] Consistent with another important feature of this embodiment, the liquid supply pipe end segment 18 a It has sharp, pointed ends 18 b 18 sharp, pointed ends b Mixing chamber 72 located at the top of the spray nozzle 71 bInside, it is used to enhance the spray tip mixing chamber 72 from its focused electrostatic field in such a way that it is emitted from the spray nozzle assembly 14 before being discharged. b Electrostatic charging and atomization of the liquid particles within. The pointed end of the supply tube 18. a Centered at the top of the spray mixing chamber 72 b Inside, it is used to collect atomized liquid particles and exit the emission path 72 b The electrostatic field is then focused onto the atomized liquid particles.

[0031] In operation, the electrostatic sprayer 70 is capable of efficiently producing fine liquid particle atomized sprays with minimal pressurized atomizing gas requirements at high liquid feed rates up to 125 kg / hr, which is particularly advantageous when using non-air atomizing gases (such as hydrogen gas commonly used in spray drying). Nitrogen is used to prevent dust explosions, which pose a higher risk with electrostatic spraying, and also has the ability to absorb large amounts of moisture. As in the previous embodiment, the liquid is charged simultaneously as it is guided through the metal liquid supply tube 18, along with the pressurized gas being guided through the annular chamber 25 surrounding the liquid supply tube 18. In this case, the charge is first generated by impacting the liquid supply tube segment 18. a The downstream end of the liquid is impacted by a surface 82 and laterally guided through a radial discharge passage 81 for interaction with pressurized atomizing gas guided across the radial liquid discharge passage 81, resulting in multi-stage liquid decomposition. The atomized liquid is then guided by the atomizing gas to the downstream mixing chamber 72 of the spray tip 71. b In the middle, the fine liquid particles are focused by an electrostatic field (from liquid supply pipe segment 18). b 18 sharp, pointed ends b (Emitting) further charging, used to charge from the outlet orifice 72 c Further atomization is achieved before emission, resulting in a very fine spray of liquid particles for efficient spray drying.

Claims

1. An electrostatic sprayer, comprising: High voltage input head; A slender nozzle body, which is supported in a downstream relationship with respect to the high-pressure input head; A liquid supply tube, made of conductive material, is disposed within the elongated nozzle body and extends downstream of the high-pressure input head; The liquid supply pipe can be connected to a pressurized liquid supply device to guide liquid through the liquid supply pipe; The elongated nozzle body and the liquid supply pipe define an annular atomizing gas passage within the elongated nozzle body; The high-voltage input head has a high-voltage cable input section, which is in electrical contact with the liquid supply pipe and is used to connect to a high-voltage power supply for charging the liquid supply pipe and the liquid that is guided through the liquid supply pipe. The high-pressure input head has a pressurized gas inlet, which is connected to the annular atomizing gas passage and is used to connect to the pressurized atomizing gas supply device to guide the pressurized atomizing gas through the annular atomizing gas passage. An internal mixing spray nozzle assembly is mounted at the downstream end of the elongated nozzle body; The spray nozzle assembly includes a spray tip mounted at the downstream end of the elongated nozzle body, the spray tip defining an internal mixing chamber downstream of the liquid supply pipe, the internal mixing chamber converging inward in the downstream direction along the length of the spray tip and communicating with the discharge orifice of the spray tip; The liquid supply tube includes an end section having a liquid passage with a reduced diameter for accelerating the liquid that guides the electrically charged liquid through the liquid supply tube. The end section of the liquid supply pipe has multiple transverse grooves for guiding the electrically charged liquid flow from the liquid supply pipe radially outward into the internal mixing chamber; An air guide, mounted near the upstream end of the spray tip in a wrapping relationship with respect to the liquid supply pipe, defines an inwardly converging gas passage communicating with the annular atomizing gas passage for directly guiding and converging pressurized atomized gas from the annular atomizing gas passage across the transverse groove through the annular gas passage defined between the air guide and the end section of the liquid supply pipe, wherein the pressurized atomized gas guided and converged by the air guide interacts with and atomizes electrically charged liquid discharged from the transverse groove, and guides the atomized liquid into the internal mixing chamber for subsequent discharge from the spray tip discharge orifice; as well as The liquid supply pipe has an inwardly converging downstream end coaxial with the inwardly converging internal mixing chamber for further charging the liquid traveling through the internal mixing chamber before being discharged from the spray tip discharge orifice.

2. The electrostatic sprayer according to claim 1, characterized in that, The electrostatic sprayer includes a center positioner for centrally supporting the downstream end of the liquid supply tube within the air guide and the spray tip. The center positioner has a central opening through which the liquid supply tube extends and a plurality of radial support legs centrally supporting the liquid supply tube within the elongated nozzle body, while allowing the passage and flow of atomized gas from the annular atomizing gas passage through an annular gas passage defined between the air guide and the end section of the liquid supply tube surrounding the liquid supply tube.

3. The electrostatic sprayer according to claim 1, characterized in that, The spray nozzle has a central discharge port aligned with the liquid supply pipe.

4. The electrostatic sprayer according to claim 1, characterized in that, The spray tip has an external radial flange that supports a reduced-diameter annular lip adjacent to the downstream end of the elongated nozzle body.

5. The electrostatic sprayer according to claim 1, characterized in that, The transverse groove defines an impact surface that guides electrically charged liquid passing through the liquid supply pipe to impact the impact surface and to be guided radially outward through the transverse groove for interaction with pressurized atomized gas guided by the air guide.

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