CN107101915A - A kind of efficient charge device of nano-scale particle thing and method - Google Patents

Abstract

The invention relates to a high-efficiency charging device and method for nanoscale particles. The charging device includes a coaxial high-voltage electrode, a discharge needle, an outer sleeve and a shell. The casing includes a casing body with a cavity inside, a sample gas inlet arranged on the top of the casing body and communicated with the cavity, a ground electrode, an outlet for charged particles, and a first opening at the bottom of the casing body. The middle and upper section of the outer sleeve extends into the cavity through the first opening. The outer sleeve includes an outer sleeve body with a discharge chamber inside, an ion injection port, a clean air inlet arranged at the lower end of the outer sleeve body and communicated with the discharge chamber, a pulling electrode, and a second Open your mouth. The middle and upper section of the high-voltage electrode and the discharge needle installed on the top of the high-voltage electrode are located in the discharge chamber, and the lower end of the high-voltage electrode is connected with the high-voltage power supply. The invention can solve the deficiencies in the prior art and realize the high-efficiency charging of nano-scale particles.

Description

An efficient charging device and method for nanoscale particles

technical field

The invention relates to the technical field of atmospheric particle charging, in particular to a device and method for efficiently charging nanoscale particles.

Background technique

For particle spectrometers based on the electromigration characteristics of particles, obtaining the known charge distribution of particles is a prerequisite for particle size classification. However, due to the diversity and complexity of particulate matter in the atmosphere, the model analysis results are often very different from the actual charging status of the particulate matter. Therefore, it is necessary to recharge the particulate matter with the help of a particulate matter charger. Generally, the charging efficiency of particles decreases continuously with the decrease of particle size, especially for nano-scale ultrafine particles, it is more difficult to achieve effective charging. The existing high-efficiency charging device for atmospheric fine particles transports free charges to the particle charging area by introducing a transfer electrode. Although this device greatly reduces the high-voltage electrostatic adsorption loss inside the charging chamber, it improves the charge of atmospheric fine particles. Electrical efficiency; but because the discharge needle is directly exposed to the air, it is easy to cause particle deposition on the discharge needle, which affects the ionization efficiency of the discharge needle, and needs to be cleaned or replaced regularly before it can continue to be used. In addition, the direction of the ion flow in the existing charging device is the same as that of the sample air flow, and many particles directly flow out from the outlet along with the air flow, without contacting the ions to complete the charging process of the particles.

Contents of the invention

The purpose of the present invention is to provide an efficient charging device and method for nano-scale particles, which can solve the deficiencies in the prior art and realize high-efficiency charging for nano-scale particles.

To achieve the above object, the present invention adopts the following technical solutions:

A high-efficiency charging device for nano-scale particles, including a coaxially arranged high-voltage electrode, a discharge needle, an outer sleeve and a casing;

The housing includes a housing body with a cavity inside, a sample gas inlet arranged on the top of the housing body and connected to the cavity, a grounding electrode arranged on the top of the housing body, and arranged at the lower section of the housing body and communicated with the cavity. The charged particle outlet and the first opening at the bottom of the shell body;

The middle and upper section of the outer sleeve extends into the cavity through the first opening; the outer sleeve includes an outer sleeve body with a discharge chamber inside, an ion injection port set on the top of the outer sleeve body, and an outer sleeve body. The lower end of the sleeve body and the clean air inlet connected to the discharge chamber, the traction electrode arranged on the outer wall of the lower end of the outer sleeve body, and the second opening opened at the bottom of the outer sleeve body;

The middle and upper sections of the high-voltage electrode and the discharge needle installed on the top of the high-voltage electrode are all located in the discharge chamber, and the lower end of the high-voltage electrode is connected with a high-voltage power supply.

Further, the upper end of the discharge chamber is in the shape of a truncated cone, and the lower end is in the shape of a cylinder.

Further, an insulating ring is provided between the outer sleeve and the first opening; the insulating ring is made of polytetrafluoroethylene.

Further, the lower end of the high-voltage electrode is installed at the second opening through an insulating sleeve; the insulating sleeve is made of polytetrafluoroethylene.

Further, the shell body, the outer sleeve body, the sample gas inlet and the clean air inlet are all made of stainless steel.

Further, a sealing ring is provided between the insulating sleeve and the outer sleeve.

Further, the discharge needle is made of tungsten.

Further, the high voltage electrode, the traction electrode and the ground electrode are all made of copper.

The present invention also relates to a charging method of the above-mentioned high-efficiency charging device for nano-scale particles, the method comprising the following steps:

(1) The clean air flow enters the discharge chamber from the clean air inlet;

(2) The end of the high-voltage electrode is connected to high voltage through a high-voltage power supply, and the tip of the discharge needle generates a tip discharge, thereby ionizing the clean air flow entering the discharge chamber and generating a large number of ions;

(3) Connect the end of the traction electrode to the traction voltage to form a traction electric field in the cavity of the casing;

(4) Under the impetus of the unionized clean air flow, the ions in the discharge chamber enter the cavity of the shell through the ion injection port, and under the action of the traction electric field, the ions accelerate upward;

(5) The sample gas enters the cavity of the shell from the sample gas inlet;

(6) In the cavity of the shell, the ions collide with the sample gas, and the ions are attached to the particles in the sample gas to charge the particles, thereby obtaining charged particles;

(7) Under the action of the sample gas flow, the charged particles flow out from the outlet of the charged particles.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention passes clean air into the discharge chamber, and by setting the flow rate of the sample gas and the clean air flow, the sample gas will not enter the discharge chamber, so that the discharge needle will not be The pollution ensures the stability of the discharge, so that the charging device of the present invention can work for a long time. The invention separates the discharge chamber from the chamber where the sample gas is combined with ions to ensure that the discharge needle will not be polluted and the stability of the discharge is ensured, thereby ensuring the stability of the ion concentration.

(2) In the present invention, the clean air flow is ionized in the discharge chamber below the sample gas inlet by passing the sample gas from the top of the entire device, so that the positive and negative ions generated after the clean air flow is ionized and in the sample gas Particles move relative to each other and collide. Moreover, the present invention accelerates the movement of positive and negative ions by introducing a traction electric field, which can increase the chance of collision between ions and particles, and improve the charging efficiency of particles.

Description of drawings

Fig. 1 is a schematic structural view of a device for efficiently charging nanoscale particles in the present invention.

in:

1. High voltage electrode, 2. Insulating sleeve, 3. Outer sleeve, 4. Traction electrode, 5. Discharge needle, 6. Charged particle outlet, 7. Shell, 8. Grounding electrode, 9. Insulating ring, 10. Sample gas inlet, 11, clean air inlet, 12, sealing ring.

detailed description

The present invention will be further described below in conjunction with accompanying drawing:

As shown in FIG. 1 , an efficient charging device for nanoscale particles includes a coaxial high-voltage electrode 1 , a discharge needle 5 , an outer sleeve 3 and a casing 7 .

The housing 7 includes a housing body with a cavity inside, a sample gas inlet 10 arranged on the top of the housing body and connected to the cavity, a ground electrode 8 arranged on the top of the housing body, and a ground electrode 8 arranged at the middle and lower section of the housing body and connected to the cavity. The cavity is connected with the charged particle outlet 6 and the first opening at the bottom of the shell body.

The middle and upper section of the outer sleeve 3 protrudes into the cavity through the first opening. The outer sleeve 3 includes an outer sleeve body with a discharge chamber inside, an ion injection port provided on the top of the outer sleeve body, a clean air inlet 11 arranged at the lower end of the outer sleeve body and communicated with the discharge chamber, a set The pulling electrode 4 on the outer wall at the lower end of the outer sleeve body and the second opening opened at the bottom of the outer sleeve body. The introduction of the pull electrode can accelerate the movement of ions, thereby increasing the chance of collision between ions and particles, making particles more easily charged.

The middle and upper sections of the high-voltage electrode 1 and the discharge needle 5 screwed to the top of the high-voltage electrode 1 are located in the discharge chamber, and the lower end of the high-voltage electrode 1 is connected to a high-voltage power supply.

Further, the upper end of the discharge chamber is in the shape of a truncated cone or a cone, and the lower end is in the shape of a cylinder. By designing the upper end of the discharge chamber into a frustoconical or conical shape, the diameter of the air outlet can be gradually reduced from large to accelerated ion movement speed.

Further, an insulating ring 9 is provided between the outer sleeve 3 and the first opening; the insulating ring 9 is made of polytetrafluoroethylene.

Further, the lower end of the high-voltage electrode 1 is installed at the second opening through an insulating sleeve 2; the insulating sleeve 2 is made of polytetrafluoroethylene. The insulating sleeve separates the high-voltage electrode from the outer sleeve to ensure insulation of the outer sleeve and safe operation.

Further, the shell body, outer sleeve body, sample gas inlet 10 and clean air inlet 11 are all made of stainless steel.

Further, a sealing ring 12 is provided between the insulating sleeve 2 and the outer sleeve 3 .

Further, the discharge needle 5 is made of tungsten.

Further, the high voltage electrode 1, the pulling electrode 4 and the ground electrode 8 are all made of copper.

The present invention also relates to a charging method of the above-mentioned high-efficiency charging device for nano-scale particles, the method comprising the following steps:

(1) The clean air flow enters the discharge chamber from the clean air inlet at a flow rate of 0.5 liters per minute;

(2) The end of the high-voltage electrode is connected to a positive or negative high voltage of 5 kV through a high-voltage power supply, and the tip of the discharge needle generates a tip discharge, thereby ionizing the clean air flow entering the discharge chamber and generating a large amount of positive or negative negative ions;

(3) Connect the end of the traction electrode to a 20V traction voltage to form a traction electric field in the cavity at the upper end of the casing;

(4) Under the impetus of the unionized clean air flow, the positive or negative ions in the discharge chamber enter the cavity at the upper end of the shell through the ion injection port, and under the action of the traction electric field, the positive or negative ions accelerate upward movement ;

(5) The sample gas enters the cavity of the shell from the sample gas inlet at a flow rate of 1.5 liters per minute;

(6) In the cavity of the shell, the positive or negative ions collide with the sample gas in opposite directions, and the positive or negative ions attach to the particles in the sample gas, making the particles positively or negatively charged, thereby obtaining charged particles. By setting the flow rate of the clean air flow, it can be ensured that the sample gas will not enter the frustum-shaped discharge chamber at the upper end of the insulating sleeve, and the discharge needle will not be polluted.

(7) Under the action of the sample gas flow, the charged particles flow out from the outlet of the charged particles.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (9)

1. a kind of efficient charge device of nano-scale particle thing, it is characterised in that：Including the high-field electrode being coaxially disposed, spray point, Outer sleeve and shell；

The shell includes the internal outer cover body provided with cavity, is arranged on the sample gas being connected at the top of outer cover body and with cavity Import, the grounding electrode being arranged at the top of outer cover body, charged for being arranged on hypomere in outer cover body and being connected with cavity The outlet of grain thing and the first opening for being opened in outer cover body bottom；

The middle epimere of the outer sleeve is extend into cavity by the first opening；The outer sleeve includes internal provided with electric discharge chamber Outer sleeve body, be opened in the ion jet of outer sleeve bodies top, be arranged on outer sleeve body lower end and and discharge cavity Pure air import that room is connected, the extraction electrodes being arranged on outer sleeve body lower end outer wall and it is opened in outer sleeve sheet Second opening of body bottom；

The middle epimere and the spray point at the top of high-field electrode of the high-field electrode are respectively positioned in discharge cavity room, high-field electrode Lower end be connected with high voltage power supply.

2. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The electric discharge chamber Upper end to be round table-like, lower end is cylindric.

3. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The outer sleeve with Dead ring is provided between first opening；The dead ring uses polytetrafluoroethylene (PTFE) material.

4. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The high-field electrode Lower end by insulating sleeve be arranged on the second opening at；The insulating sleeve uses polytetrafluoroethylene (PTFE) material.

5. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The shell sheet Body, outer sleeve body, the import of sample gas and pure air import use stainless steel.

6. a kind of efficient charge device of nano-scale particle thing according to claim 3, it is characterised in that：The insulating sleeve Sealing ring is provided between outer sleeve.

7. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The spray point is adopted Use tungsten material.

8. a kind of efficient charge device of nano-scale particle thing according to claim 1, it is characterised in that：The high-tension electricity Pole, extraction electrodes and grounding electrode use copper material.

9. the Charging Techniques of the efficient charge device of nano-scale particle thing according to claim 1 ~ 8 any one, its feature It is：This method comprises the following steps：

（1）Pure air stream is entered in electric discharge chamber by pure air import；

（2）The end of high-field electrode is accessed by high pressure by high voltage power supply, the tip of spray point produces point discharge, so that entering Enter to the pure air stream in electric discharge chamber and ionize, produce substantial amounts of ion；

（3）Traction voltage is accessed into the end of extraction electrodes, traction electric field is formed in the cavity of shell；

（4）Under the promotion for the pure air stream not being ionized, the ion in electric discharge chamber is entered outer by ion jet In the cavity of shell, and in the presence of traction electric field, ion accelerates upward motion；

（5）In the cavity that sample gas enters shell by sample gas import；

（6）In the cavity of shell, ion and sample gas are collided, and ion is attached on the particulate matter in sample gas, makes particulate matter It is powered, so as to obtain charged particle thing；

（7）In the presence of sample gas air-flow, charged particle thing is exported by electrically charged particle thing to flow out.