CN107570343B - A gas-liquid two-fluid electrostatic atomization device - Google Patents

Abstract

The invention provides a gas-liquid double-fluid electrostatic atomization device, which comprises an air discharge cavity, a brush-shaped electrode, a needle-shaped grounding electrode, an electrified air channel, a shell, a gas-liquid mixing cavity, an isolation tube, a pressing body and a pressing cover, wherein the air discharge cavity is provided with a plurality of air inlets; the air discharge cavity is communicated with the gas-liquid mixing cavity through an electrified air channel; one end of the isolation tube is vertically connected with the shell; the outer side of the isolation tube is a circular air passage, the inside of the isolation tube is a cylindrical liquid passage, and a plurality of pairs of vent holes are arranged between the air passage and the liquid passage; the liquid channel is communicated with the gas-liquid mixing cavity; an air inlet channel is designed at the other end of the isolation tube, and the air inlet channel is communicated with the air channel; the invention utilizes the corona discharge of the electrode to generate a large amount of electrons and anions, and the electrons and anions are fully mixed with the liquid after the air enters the mixing cavity, so that the liquid is charged, the electrode is prevented from being in direct contact with the liquid, and the safety is improved. Meanwhile, inflow liquid forms two-phase fluid with gas-liquid phase, so that the liquid drop has higher resistance, effectively prevents charge loss, and greatly improves the charge-to-mass ratio of liquid drops.

Description

A gas-liquid two-fluid electrostatic atomization device

technical field

The invention relates to a gas-liquid two-fluid electrostatic atomization device, in particular to a gas-liquid two-fluid electrostatic atomization device which utilizes air discharge to realize efficient charging of droplets, and belongs to the technical field of fluid machinery.

Background technique

Electrostatic spray technology is an atomization technology in which liquid is broken into charged droplets under the participation of high-voltage static electricity. Compared with other spray methods, this atomization process has many advantages over conventional atomization. Droplet charging can reduce the surface tension of the liquid and the atomization resistance, so that the droplets are broken into smaller droplets, and the diameter distribution becomes more uniform. Due to its good spray characteristics and deposition effect, electrostatic spray technology is widely used in pesticide spraying, sanitation and epidemic prevention disinfection, spray cooling and other fields. In order to apply electrostatic spray technology to charge droplets, relevant researchers have provided different solutions.

The nozzle disclosed in the patent application number CN201510161434.4 and named "An Electrostatic Atomization Nozzle" uses a ribbed rotating body to rotate at high speed to form a cone-shaped liquid mist, and realizes a charged low-voltage rotating electrostatic mist through a needle-shaped electrode. Nozzle device. The device is charged by adding an external electrostatic ring in front of the nozzle. Because the external electrostatic ring is easily adhered by the liquid medicine when the mist passes through, resulting in short circuit or high voltage breakdown, the electrostatic effect and safety are difficult to guarantee. At the same time, in this device, the gas enters the nozzle from the axial direction, and the liquid enters the nozzle from the tangential direction. When the gas-liquid two-phase is mixed, there is not enough mixing space, so a strong turbulent vortex will be generated, so that a stable gas-liquid cannot be formed. The two-phase flow field structure affects the atomization effect;

The nozzle disclosed in the patent application number CN201510105034.1, titled "A Liquid Fuel Electrostatic Atomization Nozzle with Gas-liquid Coaxial Injection", uses high-voltage static electricity and compressed airflow to improve the atomization effect of fuel, but its charging electrode directly Contact with the fuel, on the one hand, the fuel will act as a conductor to lead the current to the fuel tank, which increases the danger. On the other hand, the fuel is mixed with air and directly contacts the high-voltage electrode, so the safety is difficult to guarantee.

The nozzle structure disclosed by the patent application number CN200920047470.8, titled "air-liquid coaxial inflow electrostatic atomization nozzle" mainly solves the problem of efficient and safe pesticide application on agricultural plant protection machinery. It simply adopts the gas-liquid coaxial method, A gas-liquid mixed flow state is formed in the mixing chamber, and the mixed liquid passes through the swirl sheet with liquid flow holes to form a spray. Since the pesticide solution is generally conductive, the charging method of the liquid spray is inductive charging, and the atomization effect and the activity of the droplets are improved by inductive charging. However, since liquid fuels are polar media with extremely low conductivity, they cannot be charged by induction charging, but can only be charged by contact charging and corona charging, so the spray efficiency of this nozzle is not high.

The above-mentioned patents apply electrostatic spraying technology, and most of them use high-voltage electrode contact charging or corona charging to atomize and charge the droplets, so that the electrodes are easy to break down, and there are potential safety hazards. At the same time, the charged droplets are good conductors, and the high-voltage current will cause damage to the device components.

Contents of the invention

In order to avoid and overcome the above disadvantages, the object of the present invention is to provide a stable gas-liquid two-phase flow field structure, improve the charging efficiency and electrical safety of droplets, achieve good spray characteristics and atomization capabilities, and realize liquid A gas-liquid two-fluid electrostatic atomization device with high-efficiency charging.

The technical solution for realizing the present invention is: a gas-liquid two-fluid electrostatic atomization device, including an air discharge chamber, a brush-shaped electrode, a needle-shaped ground electrode, a charged air channel, a casing, a gas-liquid mixing chamber, an isolation tube, and a pressing body and gland;

The air discharge chamber is a hollow cylinder with a brush-shaped electrode and a needle-shaped ground electrode inside. The air discharge chamber communicates with the gas-liquid mixing chamber in the shell through a charged air channel; the charged air channel and the air discharge chamber have a shaft to the included angle;

The lower end of the shell seals the gas-liquid mixing chamber through a circular pressure body, and a nozzle is arranged at the center of the pressure body; the gland fixes the pressure body, and the gland is connected to the lower end of the shell through threads;

In the middle part of the shell, one end of the isolating tube is vertically connected to the shell through threads; the outside of the isolating tube is a circular air channel, and the inside of the isolating tube is a cylindrical liquid channel. Several pairs of symmetrical air holes, the air channel and the liquid channel are connected through the air hole; the liquid channel is coaxial with the air channel, and the liquid channel is connected with the gas-liquid mixing chamber; the other end of the isolation tube is designed to have a certain angle with the liquid channel. The air intake channel communicates with the air channel;

The isolating tube is made of insulating material, and the inner wall of the part of the isolating tube that is distributed with vent holes is coated with a hydrophobic surface coating.

In the above solution, the tip of the needle-shaped ground electrode points to the brush part of the brush-shaped electrode, and the needle-shaped ground electrode and the brush-shaped electrode are coaxially distributed with the air discharge chamber and fixed in the air discharge chamber;

There is a wire hole on the air discharge chamber, and the wire is connected to the two electrodes through the wire hole; the brush-shaped electrode is connected to the negative high voltage generator outside the air discharge chamber through the wire, and the needle-shaped grounding electrode is connected to the ground through the wire.

Further, the axial distance from the tip of the needle-shaped ground electrode to the brush-shaped electrode is 13mm-16mm.

Further, the axial distance from the tip of the needle-shaped ground electrode to the brush-shaped electrode is 15 mm.

In the above solution, the number of the ventilation holes is at least 3 pairs, and the interval between the ventilation holes is 10 mm; the diameter of the ventilation holes is 3 mm.

In the above solution, the isolation tube is made of insulating polytetrafluoroethylene material.

In the above scheme, the axial angle between the charged air passage and the air discharge chamber is 20°-30°; the lower end of the charged air passage coincides with the axis of the gas-liquid mixing chamber.

In the above solution, the included angle between the liquid channel and the air inlet channel is 60°.

The working process and charge atomization method of the present invention are as follows: the liquid flows through the vent hole of the isolation tube through the liquid channel, and the gas in the air channel divides the liquid column into several sections to form a two-phase fluid between the gas and liquid phases. Since the isolation tube is made of insulating polytetrafluoroethylene, and the inner wall is coated with a hydrophobic surface coating, the wall will not be stained with liquid, so that a stable two-phase fluid between gas and liquid is formed here. The two-phase fluid here has a high resistance, which can effectively prevent the charges in the gas-liquid mixing chamber from being led away. The formed two-phase fluid flows through the end of the liquid channel and is injected into the gas-liquid mixing chamber perpendicular to the axis of the air discharge chamber. At the same time, the two discharge electrodes installed in the air discharge chamber generate a large number of electrons and negative ions through corona discharge, and flow through the charged air channel into the gas-liquid mixing chamber. The charged air channel and the axis of the gas-liquid mixing chamber have an angle of 20° to 30°, forming a vortex, which makes the gas-liquid two-phase flow have greater shear force, and is more conducive to the full integration of electrons, negative ions and liquid in the gas-liquid mixing chamber. mix. The fully atomized and charged liquid is sprayed out through the nozzle on the pressure body to form an electrostatic spray.

Compared with prior art, the advantage of the present invention is:

1. The present invention uses air with a large number of electrons and negative ions to charge the droplets, avoiding direct contact between the electrodes and the liquid, and improving safety;

2. In the inflow section of the liquid channel, by designing the air channel coaxial with the liquid channel, the inflow liquid forms a two-phase fluid between gas and liquid, which has a high resistance, effectively prevents the loss of charge, and greatly improves The droplet charge-to-mass ratio;

3. In the present invention, because the isolation tube is made of insulating polytetrafluoroethylene material, and the inner wall is coated with a hydrophobic surface coating, the wall surface will not be stained with liquid, so that a stable two-phase fluid between gas and liquid is formed here;

4. In the present invention, the gas-liquid is mixed in advance in the gas-liquid mixing chamber, and a lower spray pressure is used to obtain better spray characteristics, so the energy consumption is lower;

5. The charged air channel of the present invention has an included angle of 20° to 30° with the axis of the gas-liquid mixing chamber, forming a vortex, so that the gas-liquid two-phase flow has greater shear force, which is more conducive to the electrons and negative ions in the gas-liquid mixing chamber Adequate mixing with liquid;

6. The present invention also has good adaptability to high-viscosity liquid atomization, and can be widely used in the fields of pesticide spraying, spray cooling, electrostatic spray desulfurization and dust removal, etc.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the present invention;

Fig. 2 is a schematic diagram of the shell structure of an embodiment of the present invention;

Fig. 3 is a schematic diagram of the structural arrangement of the liquid channel and the air channel of the embodiment of the present invention.

In Figure 1, 1. Liquid channel; 2. Inlet channel; 3. Air channel; 4. Vent hole; 5. Isolation tube; 6. Needle ground electrode; 7. Negative high voltage generator; 8. Brush electrode ; 9. Air discharge chamber; 10. Charged air channel; 11. Shell; 12. Gas-liquid mixing chamber; 13. Nozzle; 14. Pressure body; 15. Gland.

Detailed ways

The present invention will be described in further detail below in conjunction with the specific embodiments of the accompanying drawings, but the protection scope of the present invention is not limited thereto.

As shown in Figure 1, a gas-liquid two-fluid electrostatic atomization device includes an air discharge chamber 9, a brush-shaped electrode 8, a needle-shaped ground electrode 6, a negative high voltage generator 7, a charged air channel 10, and a gas-liquid mixing chamber 12. Liquid channel 1, air inlet channel 2, air channel 3, isolation tube 5, vent hole 4, casing 11, pressure body 14 and gland 15; the air discharge chamber 9 is a hollow cylinder with a brush-like The electrode 8 and the needle-shaped grounding electrode 6, the air discharge chamber 9 communicate with the gas-liquid mixing chamber 12 through the charged air channel 10; The nozzle 13; the gland 15 fixes the pressure body 14, and the gland 15 is connected to the lower end of the casing 11 through threads.

In the middle part of the housing 11, one end of the isolation tube 5 is vertically connected to the housing 11 through threads; the outer side of the isolation tube 5 is a circular air channel 3, and the inner side is a cylindrical liquid channel 1, and the gas channel 3 and the liquid channel are connected through the isolation tube 5. The channel 1 is separated; wherein the liquid channel 1 is coaxial with the air channel 3, and the liquid channel 1 is connected with the gas-liquid mixing chamber 12; at the left end of the isolation tube 5, an air inlet channel 2 with an angle of 60° with the liquid channel 1 is designed, The intake channel 2 communicates with the air channel 3 .

As shown in Figure 2, the needle point of the needle-shaped ground electrode 6 points to the brush part of the brush-shaped electrode 8, and the two electrodes are coaxially distributed with the air discharge chamber 9, and are fixed in the air discharge chamber 9; The axial distance from the needle tip to the brush-shaped electrode 8 is 13 mm to 16 mm, preferably 15 mm. When the voltage is supplied by the negative high voltage generator, such an axial distance can not only ensure corona discharge, generate a large amount of negative ions, but also avoid Break down the air; there is a wire hole on the air discharge chamber 9, and the wire is connected to the two electrodes through the wire hole; the brush-shaped electrode 8 is connected to the negative high voltage generator 7 through the wire, and the negative high voltage generator 7 is fixed on the air discharge chamber 9 Outside; the needle ground electrode 6 is connected to the ground through a wire.

The axial angle between the charged air passage 10 and the air discharge chamber 9 is 20°-30°, and the lower end of the charged air passage 10 coincides with the axis of the gas-liquid mixing chamber 12 . The charged air channel 10 and the gas-liquid mixing chamber 12 have an included angle of 20° to 30°, which makes it easier to form eddy currents and make the gas-liquid two-phase flow have greater shear force, which is more conducive to the electrons and negative ions in the gas-liquid mixing chamber 12. Mix well with liquid.

As shown in Figure 3, at the place where the air channel 3 is separated from the liquid channel 1, the isolation tube 5 distributes four pairs of ventilation holes 4 with a symmetrical diameter of 3 mm up and down every 10 mm to the left; The channel 1 is connected; the isolation tube 5 is made of insulating polytetrafluoroethylene material, and at the same time, the inner wall of the isolation tube 5 is coated with a hydrophobic surface coating at the part where the vent holes 4 are distributed. The liquid flows through the vent hole 4 of the isolation tube through the liquid channel 1, and the gas in the air channel 3 will divide the liquid column into several sections to form a two-phase fluid between the gas and liquid phases. Since the isolation tube 5 is made of insulating polytetrafluoroethylene, and the inner wall is coated with a hydrophobic surface coating, the wall will not be stained with liquid, so that a stable two-phase fluid between gas and liquid is formed here. The two-phase fluid here has a relatively high resistance, which can effectively prevent the charges in the gas-liquid mixing chamber 12 from being led away. The formed two-phase fluid flows through the end of the liquid channel, and injects into the gas-liquid mixing chamber 12 perpendicular to the axis of the air discharge chamber 9 .

The working process and charge atomization method of the present invention are as follows: the liquid flows through the liquid channel 1 through the vent hole 4 of the isolation tube 5, and the gas in the air channel 3 will divide the liquid column into several sections to form a gas-liquid phase. two-phase fluid. Since the isolating tube 5 is made of insulating polytetrafluoroethylene material, and the inner wall is coated with the wall surface so as not to be stained with liquid, a stable two-phase fluid between gas and liquid is formed here. The two-phase fluid here has a relatively high resistance, which can effectively prevent the charges in the gas-liquid mixing chamber 12 from being led away. The formed two-phase fluid flows through the end of the liquid channel 1 and injects into the gas-liquid mixing chamber 12 perpendicular to the axis of the air discharge chamber 9 . At the same time, the two discharge electrodes installed in the air discharge chamber 9 generate a large number of electrons and negative ions through corona discharge, and flow through the charged air channel 10 into the gas-liquid mixing chamber 12 . The charged air channel 10 and the axis of the gas-liquid mixing chamber 12 have an included angle of 20° to 30°, forming a vortex, making the gas-liquid two-phase flow have greater shear force, which is more conducive to the interaction between electrons, negative ions and the gas-liquid mixing chamber 12. Thorough mixing of liquids. The fully atomized and charged liquid is sprayed out through the nozzle 13 on the pressure body 14 to form an electrostatic spray.

The present invention utilizes the electrode corona discharge to generate a large amount of electrons and negative ions, and follows the air into the gas-liquid mixing chamber 12 to fully mix with the liquid to charge the liquid, thus avoiding direct contact between the electrodes and the liquid and improving safety. At the same time, in the inflow section of the liquid passage, through the reasonable design of the air passage 3 and the liquid passage 1, the inflow liquid forms a two-phase fluid between gas and liquid, which has high resistance, effectively prevents the loss of charge, and greatly improves the liquid flow rate. Drop charge to mass ratio. The invention also has good adaptability to high-viscosity liquid atomization, and can be widely used in the fields of pesticide spraying, spray cooling, electrostatic spray desulfurization and dust removal, and the like.

The described embodiment is a preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation, without departing from the essence of the present invention, any obvious improvement, replacement or modification that those skilled in the art can make Modifications all belong to the protection scope of the present invention.

Claims (6)

1. The gas-liquid double-fluid electrostatic atomization device is characterized by comprising an air discharge cavity (9), a brush-shaped electrode (8), a needle-shaped grounding electrode (6), an electrified air channel (10), a shell (11), a gas-liquid mixing cavity (12), an isolation tube (5), a pressing body (14) and a pressing cover (15);

the air discharge cavity (9) is a hollow cylinder, a brush-shaped electrode (8) and a needle-shaped grounding electrode (6) are arranged in the air discharge cavity (9) and communicated with the gas-liquid mixing cavity (12) in the shell (11) through an electrified air channel (10), and the electrified air channel (10) and the air discharge cavity (9) have an axial included angle;

the lower end of the shell (11) seals the gas-liquid mixing cavity (12) through a circular pressing body (14), and a nozzle (13) is arranged at the center of the pressing body (14); the pressing cover (15) fixes the pressing body (14), and the pressing cover (15) is connected with the lower end of the shell (11);

one end of the isolation tube (5) is vertically connected with the shell (11) at the middle part of the shell (11); the outside of the isolation tube (5) is a circular air passage (3), the inside of the isolation tube (5) is a cylindrical liquid passage (1), a plurality of pairs of vent holes (4) which are vertically symmetrical are arranged between the air passage (3) and the liquid passage (1), and the air passage (3) is communicated with the liquid passage (1) through the vent holes (4); the liquid channel (1) is coaxial with the air channel (3), and the liquid channel (1) is communicated with the gas-liquid mixing cavity (12); an air inlet channel (2) with a certain included angle with the liquid channel (1) is designed at the other end of the isolation tube (5), and the air inlet channel (2) is communicated with the air channel (3);

the isolating pipe (5) is made of insulating materials, and part of the inner wall of the isolating pipe (5) with the air holes (4) distributed therein is plated with a hydrophobic surface coating;

the needle point of the needle-shaped grounding electrode (6) points to the brush part of the brush-shaped electrode (8), and the needle-shaped grounding electrode (6) and the brush-shaped electrode (8) are coaxially distributed with the air discharge cavity (9) and are fixed in the air discharge cavity (9);

the air discharge cavity (9) is provided with a wire guide hole, the brush-shaped electrode (8) is connected with a negative high-voltage generator (7) outside the air discharge cavity (9) through a wire, and the needle-shaped grounding electrode (6) is connected with the ground through a wire;

the axial included angle between the charged air channel (10) and the air discharge cavity (9) is 20-30 degrees; the lower end of the charged air channel (10) coincides with the axis of the gas-liquid mixing cavity (12).

2. A gas-liquid double-fluid electrostatic atomizer according to claim 1, wherein the axial distance from the tip of the needle-shaped grounding electrode (6) to the brush-shaped electrode (8) is 13-mm mm.

3. A gas-liquid double fluid electrostatic atomizer according to claim 2, characterized in that the axial distance from the tip of the needle-shaped earthing electrode (6) to the brush-shaped electrode (8) is 15mm.

4. A gas-liquid dual fluid electrostatic atomizer according to claim 1, wherein the number of said air holes (4) is at least 3 pairs, the spacing between the air holes (4) being 10mm; the diameter of the vent hole (4) is 3mm.

5. A gas-liquid dual fluid electrostatic atomizer according to claim 1, wherein said isolation tube (5) is made of an insulating polytetrafluoroethylene material.

6. A gas-liquid dual fluid electrostatic atomizer according to claim 1, wherein the liquid channel (1) is at an angle of 60 ° to the air inlet channel (2).