SYSTEM FOR MEASURING CHARGE-TO-MASS RATIO OF ELECTROSTATIC ATOMIZATION NOZZLE AND MEASUREMENT METHOD USING THE SAME

Abstract

The present disclosure discloses a system for measuring a charge-to-mass ratio of an electrostatic atomization nozzle and a measurement method using the same. The system includes an electrostatic atomization nozzle, an upper cylinder, a lower cylinder, an ammeter, a liquid level tube, an ultrasonic level meter, a water storage tank, and a liquid pump. The electrostatic atomization nozzle, the upper cylinder, and the lower cylinder are sequentially connected from top to bottom. The ammeter is connected to the lower-cylinder flange. The liquid level tube is communicated with the lower cylinder. The ultrasonic level meter is mounted on an upper end of the liquid level tube. The water storage tank is located below a lower-cylinder water outlet pipe. The liquid pump can deliver a liquid in the water storage tank to the electrostatic atomization nozzle. Measurement data of the ammeter is acquired and processed by a computer in real time.

Claims

1. A system for measuring a charge-to-mass ratio of an electrostatic atomization nozzle, comprising an electrostatic atomization nozzle, an insulating bracket, an upper cylinder, a water retaining ring, a vortex breaker, a flow regulating plate, a lower cylinder, a lower-cylinder water outlet pipe, an ammeter, a metal conducting wire, a liquid level tube, an ultrasonic level meter, a water storage tank, a water supply pipe, a liquid pump, a branch pipeline, a pressure regulating valve, a throttle valve, a filter, a flowmeter, and a computer, wherein the upper cylinder is formed by circumferentially connecting a gradually expanding upper-cylinder end cover and a thin-walled columnar upper-cylinder main body, a lower end of the upper cylinder is an opening, an upper end of the upper cylinder is the upper-cylinder end cover, and an end-cover central hole is provided at a center of the upper-cylinder end cover; the lower cylinder is formed by circumferentially welding a thin-walled columnar lower-cylinder main body and a gradually reducing lower-cylinder bottom cover, an upper end of the lower cylinder is an opening, and a lower end of the lower-cylinder bottom cover is connected to the lower-cylinder water outlet pipe; the upper cylinder and the lower cylinder are connected through an upper-cylinder flange and a lower-cylinder flange, thereby forming an internal cylindrical space with two open ends between the upper cylinder and the lower cylinder; the electrostatic atomization nozzle, the upper cylinder, and the lower cylinder are sequentially connected from top to bottom, and the electrostatic atomization nozzle is mounted in middle of the end-cover central hole and sprays charged droplets vertically downward; the ammeter is connected to the lower-cylinder flange through the metal conducting wire, and is capable of measuring in real time a current produced by the charged droplets sprayed by the electrostatic atomization nozzle into the lower cylinder; the charged droplets sprayed by the electrostatic atomization nozzle are gathered in the lower cylinder, and under influence of its own gravity, the liquid flows to the water storage tank through the lower-cylinder water outlet pipe, while a bottom end of the water storage tank is communicated with the water supply pipe and the liquid pump, enabling the liquid in the water storage tank to be delivered by the liquid pump to an inlet of the electrostatic atomization nozzle and again sprayed into the lower cylinder by the electrostatic atomization nozzle; the water supply pipe is communicated with the branch pipeline, and a part of the liquid delivered by the liquid pump flows back to the water storage tank through the branch pipeline; the liquid level tube is L-shaped and consists of a horizontal short tube and a vertical long tube which have thin-walled round tubular structures, the horizontal short tube is communicated with the lower cylinder, and the ultrasonic level meter is mounted on an upper end of the vertical long tube and is capable of measuring in real time a liquid level height in the liquid level tube and the lower cylinder; the ammeter, the ultrasonic level meter, and the flowmeter are connected to the computer through data cables, and the computer acquires and processes in real time measurement data of the ammeter, the ultrasonic level meter, and the flowmeter, thereby achieving real-time measurement and monitoring of the charge-to-mass ratio parameter of the electrostatic atomization nozzle.

2. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 1, wherein the upper cylinder is fixed to a top fixing end through the insulating bracket, and an inner diameter of the upper-cylinder main body is equal to an inner diameter D.sub.1 of the lower-cylinder main body; the water retaining ring is of a thin-walled columnar structure coaxial with the upper cylinder and is located in the upper cylinder, and an upper end surface of the water retaining ring is connected to a lower surface of the upper-cylinder end cover; an inner diameter of the water retaining ring is a half of the inner diameter D.sub.1 of the lower-cylinder main body; several end-cover vent holes are provided on an edge of the upper-cylinder end cover, so that the internal cylindrical space formed between the upper cylinder and the lower cylinder is open to atmosphere, and the end-cover vent holes are uniformly distributed along a circumference of the edge of the upper-cylinder end cover; the insulating bracket, the upper cylinder, and the water retaining ring are made of an insulating material; the vortex breaker and the flow regulating plate are disposed in the lower-cylinder main body, the vortex breaker is of a crossed structure formed by flat steel bars, and the flow regulating plate is of a circular steel plate structure provided with circular flow-through holes; the vortex breaker and the flow regulating plate are sequentially and horizontally arranged in the lower-cylinder main body from top to bottom, and the liquid gathered in the lower cylinder passes through the vortex breaker and the flow regulating plate in process of flowing downward; the lower-cylinder flange is welded on an upper end surface of the lower-cylinder main body, the lower-cylinder flange and the upper-cylinder flange are matched and fixedly connected with each other, so that the upper cylinder and the lower cylinder are coaxially and fixedly connected, and a gasket is arranged between the lower-cylinder flange and the upper-cylinder flange to prevent leakage of the liquid; the lower cylinder and the lower-cylinder water outlet pipe are made of a metal material, and outer surfaces thereof are treated with polymer spraying to improve insulation performance from outside.

3. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 2, wherein a wall of the upper cylinder is 8-12 millimeters thick; the water retaining ring is 2-4 millimeters thick; the insulating material comprises rubber, polyethylene, polypropylene, or polyvinyl chloride; walls of the lower cylinder and the lower-cylinder water outlet pipe are 5-8 millimeters thick; the metal material for fabricating the lower cylinder and the lower-cylinder water outlet pipe comprises carbon steel, stainless steel, and aluminum alloys.

4. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 1, wherein the upper-cylinder main body and the lower-cylinder main body are of thin-walled columnar structures, and the lower-cylinder water outlet pipe is of a columnar short pipe structure, wherein an inner diameter D.sub.1 of the lower-cylinder main body ranges from 0.3-0.6 meters, an inner diameter d.sub.1 of the lower-cylinder water outlet pipe ranges from 0.001 meter-0.005 meters, and a length L.sub.1 of the lower-cylinder water outlet pipe ranges from 4d.sub.1-5d.sub.1, the lower-cylinder main body, the lower-cylinder bottom cover, and the lower-cylinder water outlet pipe are sequentially connected from top to bottom, and a height H of the lower cylinder is designed by using the following formula: $H = k_{1} .Math. \frac{q^{2}}{{gd}_{1}^{4}}$ wherein H, in meters, is the height of the lower cylinder; q, in cubic meters/second, is designed spray flow of the measurement system; g, in meters/second squared, is gravitational acceleration; d.sub.1, in meters, is the inner diameter of the lower-cylinder water outlet pipe; k.sub.1 is modification coefficient, k.sub.1=1.6-2.4; the flow regulating plate of a circular steel plate structure is horizontally arranged in the lower-cylinder main body, a certain number of circular flow-through holes are provided on a surface of the flow regulating plate, and a diameter d.sub.2 of each of the circular flow-through holes, the number N of the circular flow-through holes, and the inner diameter D.sub.1 of the lower-cylinder main body satisfy the following relationship: $0.4 .Math. << \frac{{Nd}_{2}^{2}}{{D_{1}}^{2}} .Math. << 0.6$ wherein d.sub.2, in meters, is the diameter of each of the circular flow-through holes; N is the number of the circular flow-through holes; D.sub.1, in meters, is the inner diameter of the lower-cylinder main body.

5. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 1, wherein the liquid level tube is located on a side surface of the lower cylinder and consists of the horizontal short tube and the vertical long tube welded together, the horizontal short tube is horizontally arranged, and the vertical long tube is vertically arranged; a liquid level tube vent hole is provided on an upper end of the vertical long tube, so that the liquid level tube is open to atmosphere, and meanwhile, the horizontal short tube is communicated with the lower cylinder, thereby forming mutual communication between the liquid level tube, the lower cylinder, and the atmosphere, wherein a center of the liquid level tube vent hole is higher than an end surface of the lower-cylinder flange; the ultrasonic level meter is mounted on the upper end of the vertical long tube, a probe of the ultrasonic level meter faces vertically downward, and the ultrasonic level meter is capable of measuring in real time the liquid level height in the liquid level tube and the lower cylinder; the liquid level tube is made of a metal material, and an outer surface thereof is treated with polymer spraying; an input end of the ammeter is connected to an outer surface of the lower-cylinder flange through the metal conducting wire, and an output end of the ammeter is connected to a ground terminal; the water storage tank is a cylindrical vessel having a closed bottom end and an opening upper end and is located below the lower-cylinder water outlet pipe, the water storage tank is communicated with the inlet of the electrostatic atomization nozzle through the water supply pipe, the liquid pump, the throttle valve, the filter, and the flowmeter, and the flowmeter is located near the inlet of the electrostatic atomization nozzle and acquires in real time a spray flow of the electrostatic atomization nozzle; the water supply pipe is arranged between the liquid pump and the throttle valve and is connected to the branch pipeline; the pressure regulating valve is disposed on the branch pipeline and is capable of being controlled to adjust an output pressure of the liquid pump and a spray pressure of the electrostatic atomization nozzle; an outlet of the branch pipeline faces the opening upper end of the water storage tank, enabling a part of the liquid to flow back into the water storage tank through the branch pipeline and the pressure regulating valve; the water storage tank is made of a metal material, and the water supply pipe and the branch pipeline are made of an insulating material.

6. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 5, wherein a metal material for fabricating the liquid level tube and the water storage tank comprises carbon steel, stainless steel, and aluminum alloys; a wall of the liquid level tube is 4-6 millimeters thick and is not thicker than that of the lower cylinder; the ammeter is selected from a microammeter or picoammeter; the insulating material for fabricating the water supply pipe and the branch pipeline comprises rubber, polyethylene, polypropylene, or polyvinyl chloride.

7. The system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 1, wherein the measurement system has the following two working modes: first working mode, being used for measuring the charge-to-mass ratio parameter of the electrostatic atomization nozzle of an electrostatic sprayer in a working state, and in this case, the electrostatic sprayer is directly connected to the electrostatic atomization nozzle, the electrostatic atomization nozzle is a part of the electrostatic sprayer, and during a spray test, the electrostatic sprayer provides the electrostatic atomization nozzle with the liquid to be sprayed; when the charge-to-mass ratio parameter of the electrostatic atomization nozzle is measured in the first working mode, the liquid pump, the pressure regulating valve, and the throttle valve are in a closed state; and second working mode, wherein the electrostatic atomization nozzle functions as an independent component to be measured and is not connected to an external electrostatic sprayer, the liquid is driven by the liquid pump to flow in closed circulation in the electrostatic atomization nozzle, the lower cylinder, the lower-cylinder water outlet pipe, the water storage tank, and the water supply pipe, so that the electrostatic atomization nozzle is continuously supplied with the liquid to be sprayed and proceeding of the spray test is ensured, and meanwhile, the pressure regulating valve is controlled to adjust an output pressure of the liquid pump and a spray pressure of the electrostatic atomization nozzle, to realize measurement of the charge-to-mass ratio parameter under different spray pressures; when the charge-to-mass ratio parameter of the electrostatic atomization nozzle is measured in the second working mode, the liquid pump, the pressure regulating valve, and the throttle valve are in an open state.

8. A measurement method using the system for measuring the charge-to-mass ratio of the electrostatic atomization nozzle according to claim 7, wherein when the measurement system is in the first working mode, the computer acquires in real time the measurement data of the ammeter and the ultrasonic level meter, and the measurement method comprises specifically the following steps: during a spray test of the electrostatic atomization nozzle, acquiring, by the computer, in real time data of a current I output by the ammeter according to a sampling period T.sub.1 of the ammeter, and acquiring in real time data of a liquid level height h output by the ultrasonic level meter according to a sampling period T.sub.2 of the ultrasonic level meter, a sampling duration of the computer being t1 ranging from 30T-50T, wherein T is a larger value of T.sub.1 and T.sub.2; during a system test, acquiring, by the computer, data of the current I and the liquid level height h within the sampling duration t1 to respectively generate arrays I1=[I1.sub.1, I1.sub.2, . . . , I1.sub.n] and h1=[h1.sub.1, h1.sub.2, . . . , h1.sub.n]; firstly calculating, by the computer, coefficients of fluctuation $S .Math. 1_{h .Math. 1} = \frac{\max (h .Math. .Math. 1) - \min (h .Math. 1)}{\overline{h .Math. .Math. 1}} .Math. .Math. and .Math. .Math. {S2}_{h .Math. .Math. 1} = | \frac{h .Math. .Math. 1_{m}}{\overline{h .Math. .Math. 1}} |,$ wherein max(h1) is a maximum value in the array h1, min(h1) is a minimum value in the array h1, $\overline{h .Math. .Math. 1} = \frac{{.Math.}_{i = 1}^{n} .Math. h .Math. 1_{i}}{n},$ and h1.sub.m is a median of the array h1; when the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 satisfy both conditions S1.sub.h1≤6% and 97%≤S2.sub.h1≤103%, processing, by the computer, the arrays I1 and h1, respectively acquiring through calculation mean values $\overline{I .Math. .Math. 1} = \frac{Σ_{i = 1}^{n} .Math. I .Math. .Math. 1_{i}}{n} .Math. .Math. and .Math. .Math. \overline{h .Math. .Math. 1} = \frac{Σ_{i = 1}^{n} .Math. h .Math. .Math. 1_{i}}{n}$ of the arrays I1 and h1, and outputting I1 and h1 as a real-time current value and a real-time liquid level height of this spray test respectively; when the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 fail to satisfy both the conditions S1.sub.h1≤6% and 97%≤S2.sub.h1≤103%, still outputting, by the computer, I1 and h1 as the real-time current value and the real-time liquid level height of this spray test respectively, and meanwhile, outputting the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 synchronously for reference of testers; and when the measurement system is in the second working mode, the computer acquires in real time the measurement data of the ammeter, the ultrasonic level meter, and the flowmeter, and the measurement method comprises specifically the following steps: during the spray test of the electrostatic atomization nozzle, acquiring, by the computer, in real time data of the current I output by the ammeter according to the sampling period T.sub.1 of the ammeter, acquiring in real time data of the liquid level height h output by the ultrasonic level meter according to the sampling period T.sub.2 of the ultrasonic level meter, and acquiring in real time data of the spray flow q output by the flowmeter according to a sampling period T.sub.3 of the flowmeter, the sampling duration of the computer being t2 ranging from 30T-50T, wherein T is the maximum value of T.sub.1, T.sub.2, and T.sub.3; during the system test, acquiring, by the computer, the data of the current I, the liquid level height h, and the spray flow q within the sampling duration t2 to respectively generate arrays I2=[I2.sub.1, I2.sub.2, . . . , I2.sub.n], h2=[h2.sub.1, h2.sub.2, . . . , h2.sub.n], and q1=[q1.sub.1, q1.sub.2, . . . , q1.sub.n]; firstly calculating, by the computer, coefficients of fluctuation $S .Math. .Math. 1_{h .Math. .Math. 2} = \frac{\max (h .Math. .Math. 2) - \min (h .Math. .Math. 2)}{\overline{h .Math. .Math. 2}}, S .Math. .Math. 2_{h .Math. .Math. 2} =  \frac{h .Math. .Math. 2_{m}}{\overline{h .Math. .Math. 2}} , S .Math. .Math. 1_{q .Math. .Math. 1} = \frac{\max (q .Math. .Math. 1) - \min (q .Math. .Math. 1)}{\overline{q .Math. .Math. 1}}, and .Math. .Math. S .Math. .Math. 2_{q .Math. .Math. 1} =  \frac{q .Math. .Math. 1_{m}}{\overline{q .Math. .Math. 1}} $ of the arrays h2 and q1, wherein max(h2) is the maximum value in the array h2, min(h2) is the minimum value in the array h2, $\overline{h .Math. .Math. 2} = \frac{Σ_{i = 1}^{n} .Math. h .Math. .Math. 2_{i}}{n}$ and h2.sub.m is the median of the array h2, max(q1) is the maximum value in the array q1, min(q1) is the minimum value in the array q1, $\overline{q .Math. .Math. 1} = \frac{Σ_{i = 1}^{n} .Math. q .Math. .Math. 1_{i}}{n}$ and q1.sub.m is the median of the array q1; when the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 satisfy all the conditions S1.sub.h2≤6%, 97%≤S2.sub.h2≤103%, S1.sub.q1≤3%, and 98%≤S2.sub.q1≤102%, processing, by the computer, the arrays I2 and h2, respectively acquiring through calculation the mean values $\overline{I .Math. .Math. 2} = \frac{Σ_{i = 1}^{n} .Math. I .Math. .Math. 2_{i}}{n} .Math. .Math. and .Math. .Math. \overline{h .Math. .Math. 2} = \frac{Σ_{i = 1}^{n} .Math. h .Math. .Math. 2_{i}}{n}$ of the arrays I2 and h2, and outputting I2 and h2 as the real-time current value and the real-time liquid level height of this spray test respectively; when the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 fail to satisfy all the conditions S1.sub.h2≤6%, 97%≤S2.sub.h2≤103%, S1.sub.q1≤3%, and 98%≤S2.sub.q1≤102%, still outputting, by the computer, I2 and h2 as the real-time current value and the real-time liquid level height of this spray test respectively, and meanwhile, outputting the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 synchronously for the reference of testers.

9. The method according to claim 8, wherein when the measurement system is in the first working mode or the second working mode, the computer system calculates the charge-to-mass ratio parameter of the electrostatic atomization nozzle according to the real-time current value and the real-time liquid level height output in the spray test, and the charge-to-mass ratio parameter is specifically calculated by using the following formula: $.Math. = k_{1} .Math. \frac{\overline{I .Math. .Math. 1}}{{ρ .Math. d}_{1}^{2} .Math. \sqrt{g .Math. \overline{h .Math. .Math. 1}}} = k_{1} .Math. \frac{\overline{I .Math. .Math. 2}}{{ρ .Math. d}_{1}^{2} .Math. \sqrt{g .Math. \overline{h .Math. .Math. 2}}}$ wherein ε, in microcoulombs/kilogram, is the charge-to-mass ratio parameter of the electrostatic atomization nozzle; ρ, in kilograms/cubic meter, is the density of the liquid to be sprayed by the electrostatic atomization nozzle; d.sub.1, in meters, is the inner diameter of the lower-cylinder water outlet pipe; g, in meters/second squared, is gravitational acceleration; k.sub.1 is modification coefficient, k.sub.1=1080-1120; I1 and I2, in amperes, are real-time current values during the test of the measurement system; h1 and h2, in meters, are real-time liquid level heights during the test of the measurement system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present disclosure is further described below with reference to the accompanying drawings and specific embodiments.

[0057] FIG. 1 is a schematic structural view of an overall solution according to an embodiment of the present disclosure;

[0058] FIG. 2 is a partial cross-sectional view of the same embodiment, which includes components such as an upper cylinder, a lower cylinder, and a liquid level tube;

[0059] FIG. 3 is a radial cross-sectional view of a vortex breaker in the same embodiment; and

[0060] FIG. 4 is a radial cross-sectional view of a flow regulating plate in the same embodiment.

[0061] In the drawings, 1. electrostatic atomization nozzle, 2. insulating bracket, 3. upper cylinder, 4. water retaining ring, 5. vortex breaker, 6. flow regulating plate, 7. lower cylinder, 8. lower-cylinder water outlet pipe, 9. ammeter, 10. metal conducting wire, 11. liquid level tube, 12. ultrasonic level meter, 13. water storage tank, 14. water supply pipe, 15. liquid pump, 16. branch pipeline, 17. pressure regulating valve, 18. throttle valve, 19. filter, 20. flowmeter, 21. water supply pipe of an electrostatic sprayer, 22. end-cover central hole, 23. upper-cylinder end cover, 24. end-cover vent hole, 25. upper-cylinder main body, 26. upper-cylinder flange, 27. lower-cylinder flange, 28. lower-cylinder main body, 29. lower-cylinder bottom cover, 30. inner diameter D.sub.1 of the lower-cylinder main body, 31. height H of the lower cylinder, 32. inner diameter d.sub.1 of the lower-cylinder water outlet pipe, 33. length L.sub.1 of the lower-cylinder water outlet pipe, 34. horizontal short tube, 35. vertical long tube, 36. liquid level tube vent hole, 37. circular flow-through hole, 38. diameter d.sub.2 of the circular flow-through hole.

DESCRIPTION OF THE EMBODIMENTS

[0062] FIG. 1 to FIG. 4 show the structure of an embodiment of the measurement system. In this embodiment, the spray flow is designed to be q=1.2 liters/minute=2×10.sup.−5 cubic meters/second. The system for measuring the charge-to-mass ratio of an electrostatic atomization nozzle and the measurement method using the same provided by the present disclosure are described clearly and completely below with reference to the accompanying drawings of the embodiment of the present disclosure.

[0063] FIG. 1 and FIG. 2 are schematic views of the system for measuring the charge-to-mass ratio of an electrostatic atomization nozzle provided by the embodiment of the present disclosure. The measurement system consists of an electrostatic atomization nozzle 1, an insulating bracket 2, an upper cylinder 3, a water retaining ring 4, a vortex breaker 5, a flow regulating plate 6, a lower cylinder 7, a lower-cylinder water outlet pipe 8, an ammeter 9, a metal conducting wire 10, a liquid level tube 11, an ultrasonic level meter 12, a water storage tank 13, a water supply pipe 14, a liquid pump 15, a branch pipeline 16, a pressure regulating valve 17, a throttle valve 18, a filter 19, a flowmeter 20, and a computer. The upper cylinder 3 consists of a gradually expanding upper-cylinder end cover 23 and a thin-walled columnar upper-cylinder main body 25. The lower end of the upper cylinder 3 is an opening, and the upper end of the upper cylinder 3 is the upper-cylinder end cover 23. An end-cover central hole 22 is provided at the center of the upper-cylinder end cover 23. The lower cylinder 7 is formed by circumferentially welding a thin-walled columnar lower-cylinder main body 28 and a gradually reducing lower-cylinder bottom cover 29. The upper end of the lower cylinder 7 is an opening. The lower end of the lower-cylinder bottom cover 29 is connected to the lower-cylinder water outlet pipe 8. The upper cylinder 3 and the lower cylinder 7 are vertically connected through an upper-cylinder flange 26 and a lower-cylinder flange 27, thereby forming an internal cylindrical space with two open ends between the upper cylinder 3 and the lower cylinder 7. The electrostatic atomization nozzle 1, the upper cylinder 3, and the lower cylinder 7 are vertically and sequentially connected from top to bottom. The electrostatic atomization nozzle 1 is mounted in the middle of the end-cover central hole 22, and sprays charged droplets vertically downward. The ammeter 9 is connected to the lower-cylinder flange 27 through the metal conducting wire 10. The charged droplets sprayed by the electrostatic atomization nozzle 1 are gathered in the lower cylinder 7. Under the influence of its own gravity, the liquid flows to the water storage tank 13 through the lower-cylinder water outlet pipe 8. The bottom end of the water storage tank 13 is communicated with the water supply pipe 14 and the liquid pump 15, enabling the liquid in the water storage tank 13 to be delivered by the liquid pump 15 to an inlet of the electrostatic atomization nozzle 1 and again sprayed into the lower cylinder 7 by the electrostatic atomization nozzle 1. The water supply pipe 14 is communicated with the branch pipeline 16. A part of the liquid delivered by the liquid pump 15 flows back to the water storage tank 13 through the branch pipeline 16. The liquid level tube 11 is L-shaped and consists of a horizontal short tube 34 and a vertical long tube 35 which have thin-walled round tubular structures. The horizontal short tube 34 is communicated with the lower cylinder 7. The ultrasonic level meter 12 is mounted on the upper end of the vertical long tube 35 and is capable of measuring in real time the liquid level height in the liquid level tube 11 and the lower cylinder 7. The ammeter 9, the ultrasonic level meter 12, and the flowmeter 20 are connected to the computer through data cables. The computer acquires and processes in real time measurement data of the ammeter 9, the ultrasonic level meter 12, and the flowmeter 20, thereby achieving real-time measurement and monitoring of the charge-to-mass ratio parameter of the electrostatic atomization nozzle 1.

[0064] As shown in FIG. 1, the insulating bracket 2 is fixedly connected between the upper-cylinder end cover 23 and a top fixing end, and thus the upper cylinder 3 is fixed to the top fixing end through the insulating bracket 2. The inner diameter of the upper-cylinder main body 25 is equal to the inner diameter D.sub.1 of the lower-cylinder main body. The inner diameter of the upper-cylinder main body 25 is 0.4 meters, and the wall of the upper cylinder 3 is 8 millimeters thick. The water retaining ring 4 is of a thin-walled columnar structure coaxial with the upper cylinder 3, and is located in the upper cylinder 3. The upper end surface of the water retaining ring 4 is connected to the lower surface of the upper-cylinder end cover 23. The inner diameter of the water retaining ring 4 is 0.2 meters, ensuring that the charged droplets sprayed by the electrostatic atomization nozzle 1 may not directly hit the inner surface of the water retaining ring 4. The water retaining ring 4 is 2 millimeters thick. Several end-cover vent holes 24 are provided on the edge of the upper-cylinder end cover 23, so that the internal cylindrical space formed between the upper cylinder 3 and the lower cylinder 7 is open to the atmosphere. The end-cover vent holes 24 are uniformly distributed along the circumference of the edge of the upper-cylinder end cover 23. The inner diameter of the end-cover vent hole 24 is 10 millimeters, and the number of the end-cover vent holes 24 is 12. The insulating bracket 2, the upper cylinder 3, and the water retaining ring 4 are made of an insulating material, such as rubber, polyethylene, polypropylene, or polyvinyl chloride.

[0065] As shown in FIG. 2, the vortex breaker 5 and the flow regulating plate 6 are disposed in the lower-cylinder main body 28. As shown in FIG. 3, the vortex breaker 5 is of a crossed structure formed by flat steel bars. As shown in FIG. 4, the flow regulating plate 6 is of a circular steel plate structure provided with circular flow-through holes 37. As shown in FIG. 2, the vortex breaker 5 and the flow regulating plate 6 are sequentially and horizontally arranged in the lower-cylinder main body 28 from top to bottom. The liquid gathered in the lower cylinder 7 passes through the vortex breaker 5 and the flow regulating plate 6 in the process of flowing downward. The lower-cylinder flange 27 is welded on the upper end surface of the lower-cylinder main body 28. The lower-cylinder flange 27 and the upper-cylinder flange 26 are matched and fixedly connected with each other, so that the upper cylinder 3 and the lower cylinder 7 are fixedly connected. A gasket is arranged between the lower-cylinder flange 27 and the upper-cylinder flange 26 to prevent leakage of the liquid. The lower cylinder 7 and the lower-cylinder water outlet pipe 8 are made of a metal material such as carbon steel, stainless steel, and aluminum alloys, and the outer surfaces thereof are treated with polymer spraying to improve insulation performance from outside. The walls of the vortex breaker 5, the flow regulating plate 6, the lower cylinder 7, and the lower-cylinder water outlet pipe 8 are all 6 millimeters thick.

[0066] As shown in FIG. 2, the upper-cylinder main body 25 and the lower-cylinder main body 28 are of thin-walled columnar structures. The inner diameter D.sub.1 of the lower-cylinder main body is 0.4 meters. The lower-cylinder water outlet pipe 8 is of a columnar short pipe structure, the inner diameter d.sub.1 of the lower-cylinder water outlet pipe is 0.0035 meters, and the length L.sub.1 of the lower-cylinder water outlet pipe is 0.015 meters. The height H of the lower cylinder is designed by using the following formula:

[00013] $H = k_{1} .Math. \frac{q^{2}}{{gd}_{1}^{4}}$

wherein H, in meters, is the height of the lower cylinder; q, in cubic meters/second, is designed spray flow of the measurement system; g, in meters/second squared, is gravitational acceleration and the value thereof in this embodiment is 9.81 meters/second squared; d.sub.1, in meters, is the inner diameter of the lower-cylinder water outlet pipe; k.sub.1 is modification coefficient, k.sub.1=1.6-2.4. According to the above design formula, the height H of the lower cylinder in this embodiment ranges from 0.44-0.65 meters, and the height H of the lower cylinder is finally determined to be 0.5 meters.

[0067] As shown in FIG. 4, the flow regulating plate 6 of a circular steel plate structure is horizontally arranged in the lower-cylinder main body 28. A certain number of the circular flow-through holes 37 are provided on the surface of the flow regulating plate 6 and are distributed at equal intervals. The diameter d.sub.2 of the circular flow-through hole, the number N of the circular flow-through holes, and the inner diameter D.sub.1 of the lower-cylinder main body satisfy the following relationship:

[00014] $0.4 .Math. .Math. << .Math. \frac{{Nd}_{2}^{2}}{D_{1}^{2}} .Math. .Math. << .Math. 0.6$

wherein d.sub.2, in meters, is the diameter of the circular flow-through hole; N is the number of the circular flow-through holes; and D.sub.1, in meters, is the inner diameter of the lower-cylinder main body. In this embodiment, the inner diameter D.sub.1 of the lower-cylinder main body is 0.4 meters, the diameter d.sub.2 of the circular flow-through hole is 60 millimeters, and the number N of the circular flow-through holes is 21, which meet the above design requirement.

[0068] As shown in FIG. 2, the liquid level tube 11 is located on the side surface of the lower cylinder 7, and consists of the horizontal short tube 34 and the vertical long tube 35 welded together. The horizontal short tube 34 is horizontally arranged, and the vertical long tube 35 is vertically arranged. The inner diameters of the horizontal short tube 34 and the vertical long tube 35 are 0.1 meter, and the walls thereof are 6 millimeters thick. A liquid level tube vent hole 36 is provided on the upper end of the vertical long tube 35, so that the liquid level tube 11 is open to the atmosphere, and meanwhile, the horizontal short tube 34 is communicated with the lower cylinder 7, thereby forming mutual communication between the liquid level tube 11, the lower cylinder 7, and the atmosphere. The center of the liquid level tube vent hole 36 is higher than the end surface of the lower-cylinder flange 27. The diameter of the liquid level tube vent hole 36 is 50 millimeters. The ultrasonic level meter 12 is mounted on the upper end of the vertical long tube 35, and the probe of the ultrasonic level meter 12 faces vertically downward. The ultrasonic level meter 12 is capable of measuring in real time the liquid level height in the liquid level tube 11 and the lower cylinder 7. The liquid level tube 11 is made of a metal material such as carbon steel, stainless steel, and aluminum alloys, and the outer surface thereof is treated with polymer spraying. The ammeter 9 is a microammeter or picoammeter. The input end of the ammeter 9 is connected to the outer surface of the lower-cylinder flange 27 through the metal conducting wire 10, and the output end of the ammeter 9 is connected to a ground terminal.

[0069] As shown in FIG. 2, the water storage tank 13 is a cylindrical vessel having a closed bottom end and an opening upper end, and is located below the lower-cylinder water outlet pipe 8. The water storage tank 13 is communicated with the inlet of the electrostatic atomization nozzle 1 through the water supply pipe 14, the liquid pump 15, the throttle valve 18, the filter 19, and the flowmeter 20. The flowmeter 20 is located near the inlet of the electrostatic atomization nozzle 1, and acquires in real time the spray flow of the electrostatic atomization nozzle 1. The liquid in the water storage tank 13 is driven by the liquid pump 15 to flow through the water supply pipe 14, the throttle valve 18, the filter 19, the flowmeter 20, and the electrostatic atomization nozzle 1, is then sprayed by the electrostatic atomization nozzle 1 into the lower cylinder 7, and again flows to the water storage tank 13 through the lower-cylinder water outlet pipe 8; therefore, the liquid flows in closed circulation in the measurement system. The water supply pipe 14 is arranged between the liquid pump 15 and the throttle valve 18 and is connected to the branch pipeline 16. The pressure regulating valve 17 is disposed on the branch pipeline 16 and is capable of being controlled to adjust the output pressure of the liquid pump 15 and the spray pressure of the electrostatic atomization nozzle 1. An outlet of the branch pipeline 16 is located above the water storage tank 13, and faces the opening upper end of the water storage tank 13, enabling a part of the liquid to flow back to the water storage tank 13 through the branch pipeline 16 and the pressure regulating valve 17. The water storage tank 13 is made of a metal material such as carbon steel, stainless steel, and aluminum alloys. The water supply pipe 14 and the branch pipeline 16 are made of an insulating material, such as rubber, polyethylene, polypropylene, or polyvinyl chloride.

[0070] As shown in FIG. 1, the measurement system has two working modes.

[0071] The first working mode is used for measuring the charge-to-mass ratio parameter of the electrostatic atomization nozzle 1 of an electrostatic sprayer in a working state. In this case, the electrostatic atomization nozzle 1 is directly connected to the electrostatic sprayer, and the external electrostatic sprayer provides the electrostatic atomization nozzle 1 with the liquid to be sprayed. The electrostatic atomization nozzle 1 is a part of the electrostatic sprayer. When the charge-to-mass ratio parameter of the electrostatic atomization nozzle 1 is measured in the first working mode, the liquid pump 15, the pressure regulating valve 17, and the throttle valve 18 are in a closed state, the computer only acquires measurement data of the ammeter 9 and the ultrasonic level meter 12, and the liquid does not flow in closed circulation in the measurement system.

[0072] In the second working mode, the electrostatic atomization nozzle 1 functions as an independent component to be measured, and is not connected to the external electrostatic sprayer. Driven by the liquid pump 15, the liquid flows in closed circulation in the components such as the electrostatic atomization nozzle 1, the lower cylinder 7, the lower-cylinder water outlet pipe 8, the water storage tank 13, and the water supply pipe 14, so that the electrostatic atomization nozzle 1 is continuously supplied with the liquid to be sprayed and the proceeding of the spray test is ensured. When the charge-to-mass ratio parameter of the electrostatic atomization nozzle 1 is measured in the second working mode, the liquid pump 15, the pressure regulating valve 17, and the throttle valve 18 are in an open state, and the computer acquires measurement data of the ammeter 9, the ultrasonic level meter 12, and the flowmeter 20 at the same time.

[0073] When the measurement system is in the first working mode, the computer acquires in real time the measurement data of the ammeter and the ultrasonic level meter. The specific measurement method includes the following steps.

[0074] During the spray test of the electrostatic atomization nozzle 1, the computer acquires in real time data of the current I output by the ammeter 9 according to a sampling period T.sub.1 of the ammeter, and acquires in real time data of the liquid level height h output by the ultrasonic level meter 12 according to a sampling period T.sub.2 of the ultrasonic level meter. The sampling duration of the computer is t1 ranging from 30T-50T, wherein T is a larger value of T.sub.1 and T.sub.2.

[0075] During the system test, the computer acquires the data of the current I and the liquid level height h within the sampling duration t1 to respectively generate arrays I1=[I1.sub.1, I1.sub.2, . . . , I1.sub.n] and h1=[h1.sub.1, h1.sub.2, . . . , h1.sub.n]. The computer firstly calculates coefficients of fluctuation

[00015] $S .Math. .Math. 1_{h .Math. .Math. 1} = \frac{\max (h .Math. .Math. 1) - \min (h .Math. .Math. 1)}{\overline{h .Math. .Math. 1}} .Math. .Math. and .Math. .Math. S .Math. .Math. 2_{h .Math. .Math. 1} = .Math. \frac{h .Math. .Math. 1_{m}}{\overline{h .Math. .Math. 1}} .Math.$

of the array h1, wherein max(h1) is the maximum value in the array h1, min(h1) is the minimum value in the array h1,

[00016] $\overline{h .Math. .Math. 1} = \frac{{.Math.}_{i = 1}^{n} .Math. h .Math. .Math. 1_{i}}{n},$

and h1.sub.m is the median of the array h1.

[0076] When the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 satisfy both the conditions S1.sub.h1≤6% and 97%≤S2.sub.h1≤103%, the computer processes the arrays I1 and h1, respectively acquires through calculation the mean values

[00017] $\overline{I .Math. .Math. 1} = \frac{{.Math.}_{i = 1}^{n} .Math. I .Math. .Math. 1_{i}}{n} .Math. .Math. and .Math. .Math. \overline{h .Math. .Math. 1} = \frac{{.Math.}_{i = 1}^{n} .Math. h .Math. .Math. 1_{i}}{n}$

of the arrays I1 and h1, and outputs I1 and h1 as the real-time current value and the real-time liquid level height of this spray test respectively. When the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 fail to satisfy both the conditions S1.sub.h1≤6% and 97%≤S2.sub.h1≤103%, the computer still outputs I1 and h1 as the real-time current value and the real-time liquid level height of this spray test respectively, and meanwhile, outputs the coefficients of fluctuation S1.sub.h1 and S2.sub.h1 synchronously for the reference of testers.

[0077] When the measurement system is in the second working mode, the computer acquires in real time the measurement data of the ammeter, the ultrasonic level meter, and the flowmeter. The specific measurement method includes the following steps.

[0078] During the spray test of the electrostatic atomization nozzle 1, the computer acquires in real time data of the current I output by the ammeter 9 according to the sampling period T.sub.1 of the ammeter, acquires in real time data of the liquid level height h output by the ultrasonic level meter 12 according to the sampling period T.sub.2 of the ultrasonic level meter, and acquires in real time data of the spray flow q output by the flowmeter 20 according to a sampling period T.sub.3 of the flowmeter. The sampling duration of the computer is t2 ranging from 30T-50T, wherein T is the maximum value of T.sub.1, T.sub.2, and T.sub.3.

[0079] During the system test, the computer acquires the data of the current I, the liquid level height h, and the spray flow q within the sampling duration t2 to respectively generate arrays I2=[I2.sub.1, I2.sub.2, . . . , I2.sub.n], h2=[h2.sub.1, h2.sub.2, . . . , h2.sub.n], and q1=[q1.sub.1, q1.sub.2, . . . , q1.sub.n]. The computer firstly calculates coefficients of fluctuation

[00018] $S .Math. .Math. 1_{h .Math. .Math. 2} = \frac{\max (h .Math. .Math. 2) - \min (h .Math. .Math. 2)}{\overline{h .Math. .Math. 2}}, S .Math. .Math. 2_{h .Math. .Math. 2} =  \frac{h .Math. .Math. 2_{m}}{\overline{h .Math. .Math. 2}} , S .Math. .Math. 1_{q .Math. .Math. 1} = \frac{\max (q .Math. .Math. 1) - \min (q .Math. .Math. 1)}{\overline{q .Math. .Math. 1}}, and .Math. .Math. S .Math. .Math. 2_{q .Math. .Math. 1} =  \frac{q .Math. .Math. 1_{m}}{\overline{q .Math. .Math. 1}} $

of the arrays h2 and q1, wherein max(h2) is the maximum value in the array h2, min(h2) is the minimum value in the array h2,

[00019] $\bar{h .Math. 2} = \frac{{.Math.}_{i = 1}^{n} .Math. h .Math. .Math. 2_{i}}{n}$

and h2.sub.m is the median of the array h2, max(q1) is the maximum value in the array q1, min(q1) is the minimum value in the array q1,

[00020] $\overline{q .Math. .Math. 1} = \frac{Σ_{i = 1}^{n} .Math. q .Math. .Math. 1_{i}}{n}$

and q1.sub.m is the median of the array q1.

[0080] When the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 satisfy all the conditions S1.sub.h2≤6%, 97%≤S2.sub.h2≤103%, S1.sub.q1≤3%, and 98%≤S2.sub.q1≤102%, the computer processes the arrays I2 and h2, respectively acquires through calculation the mean values

[00021] $\overline{I .Math. .Math. 2} = \frac{Σ_{i = 1}^{n} .Math. I .Math. .Math. 2_{i}}{n} .Math. .Math. and .Math. .Math. \overline{h .Math. .Math. 2} = \frac{Σ_{i = 1}^{n} .Math. h .Math. .Math. 2_{i}}{n}$

of the arrays I2 and h2, and outputs I2 and h2 as the real-time current value and the real-time liquid level height of this spray test respectively. When the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 fail to satisfy all the conditions S1.sub.h2≤6%, 97%≤S2.sub.h2≤103%, S1.sub.q1≤3%, and 98%≤S2.sub.q1≤102%, the computer still outputs I2 and h2 as the real-time current value and the real-time liquid level height of this spray test respectively, and meanwhile, outputs the coefficients of fluctuation S1.sub.h2, S2.sub.h2, S1.sub.q1, and S2.sub.q1 synchronously for the reference of testers.

[0081] During the test, the computer system calculates the charge-to-mass ratio parameter of the electrostatic atomization nozzle according to the real-time current value and the real-time liquid level height output in the spray test. The charge-to-mass ratio parameter is specifically calculated by using the following formula:

[00022] $.Math. = k_{1} .Math. \frac{\overline{I .Math. .Math. 1}}{{ρ .Math. d}_{1}^{2} .Math. \sqrt{g .Math. \overline{h .Math. .Math. 1}}} = k_{1} .Math. \frac{\overline{I .Math. .Math. 2}}{{ρ .Math. d}_{1}^{2} .Math. \sqrt{g .Math. \overline{h .Math. .Math. 2}}}$

wherein ε, in microcoulombs/kilogram, is the charge-to-mass ratio parameter of the electrostatic atomization nozzle; ρ, in kilograms/cubic meter, is the density of the liquid to be sprayed by the electrostatic atomization nozzle; d.sub.1, in meters, is the inner diameter of the lower-cylinder water outlet pipe; g, in meters/second squared, is gravitational acceleration; k.sub.1 is modification coefficient, k.sub.1=1080-1120; I1 and I2, in amperes, are real-time current values during the test of the measurement system; h1 and h2, in meters, are real-time liquid level heights during the test of the measurement system.

SYSTEM FOR MEASURING CHARGE-TO-MASS RATIO OF ELECTROSTATIC ATOMIZATION NOZZLE AND MEASUREMENT METHOD USING THE SAME

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B05B14/00

PERFORMING OPERATIONS; TRANSPORTING

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B05B15/40

PERFORMING OPERATIONS; TRANSPORTING

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B05B5/025

PERFORMING OPERATIONS; TRANSPORTING

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G01R29/24

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A01M7/0096

HUMAN NECESSITIES

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G01M99/008

PHYSICS

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G01R29/24

PHYSICS

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B05B5/025

PERFORMING OPERATIONS; TRANSPORTING

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