A cathode discharge tube

Abstract

The present invention discloses a cathode discharge tube, belonging to the field of optical and ionization devices. It includes a body part, a cathode discharge part and a connection part. Among them, the body part forms a closed hollow accommodation space, and a radioactive gas and / or a protective gas is filled in the accommodation space; the cathode discharge part is arranged in the accommodation space, one end of the connection part is exposed outside the body part and is suitable for being connected to the negative pole of a power supply; the other end is hermetically passed through the body part and is connected to the cathode discharge part. In the present invention, the cathode discharge part is always located under a protective atmosphere composed of a radioactive gas and / or a protective gas, without contacting with air or oxygen, ensuring that the cathode is not oxidized, prolonging the service life of the emission cathode product, and reducing the use cost of the product.

Description

Technical Field

[0001] The present invention belongs to the field of ionization devices, and in particular, to a cathode discharge tube. Background Art

[0002] The process of cathode electron emission plays an important role in gas discharge. The cathode provides electrons and maintains the current circulation. In a metal cathode, electrons can move freely, but at the cathode surface, due to the electrostatic force between electrons and lattice ions, a potential barrier is formed, preventing electrons from leaving the electrode surface. To overcome the obstacle of the surface potential barrier and move electrons outside the cathode, it is necessary to apply the work function (or called the work function). The work function depends on the material and surface state of the cathode. Ways to provide energy to electrons and release electrons from the cathode include photoemission, thermionic emission, field emission, secondary electron emission, etc.

[0003] Under the action of an externally applied strong electric field, some electrons in the cathode "pass through" the potential barrier and are emitted from the surface. According to the theory of quantum mechanics, electrons in a potential well, even if their energy does not exceed the potential energy of the potential barrier, have a certain probability of passing through the potential barrier and escaping, which is the so-called "tunneling effect". Under the action of a strong electric field, the shape of the potential barrier becomes narrower and lower, and electrons can easily pass through the potential barrier and be emitted from the surface. For a certain metal, its field emission current density can be calculated according to wave mechanics using the Fowler-Nordheim formula.

[0004] However, the cathode of the existing cathode discharge tube will come into contact with air or oxygen, resulting in cathode oxidation and cathode poisoning, and a large loss of electrons. The low work function of the cathode and the low electron emission density cause excessive electrical loss. Taking an ozone generator as an example, the ozone conversion efficiency at the beginning of the emission cathode is generally about 12%. As the use time prolongs, the ozone conversion efficiency will decrease. Summary of the Invention

[0005] In order to overcome the above technical defects, the present invention provides a cathode discharge tube to solve the problems involved in the background art.

[0006] The present invention provides a cathode discharge tube, comprising:

[0007] A body part, forming a closed hollow accommodation space, filled with radioactive gas and / or protective gas in the accommodation space;

[0008] A cathode discharge part, arranged in the accommodation space;

[0009] A connecting part, one end of which is exposed outside the body part and is adapted to be connected to the negative pole of the power supply; the other end is hermetically passed through the body part and is connected to the cathode discharge part.

[0010] Preferably or optionally, the cathode discharge part is a spiral structure formed by a conductive wire.

[0011] Preferably or optionally, the conductive wire is made of iron, cobalt, tungsten, molybdenum, nickel, gold, silver, copper, carbon or their alloy materials.

[0012] Preferably or optionally, an electron emission material is coated on the outer surface of the cathode discharge part.

[0013] Preferably or optionally, the electron emission material at least includes one of barium carbonate, strontium carbonate, and calcium carbonate.

[0014] Preferably or optionally, the body part is an ionization tube made of an insulating material.

[0015] Preferably or optionally, the ionization tube is a ceramic tube, a glass tube or a quartz tube.

[0016] Preferably or optionally, the connecting part is a tungsten rod.

[0017] Preferably or optionally, the body part and the connecting part are hermetically connected by a molybdenum sheet.

[0018] Preferably or optionally, the protective gas is nitrogen, argon, krypton, xenon, tritium, helium, neon, argon or a mixture of them.

[0019] Preferably or optionally, when the cathode discharge tube is in use, it can generate one or more reactions of light, plasma, corona, electroion, and arc.

[0020] The present invention relates to a cathode discharge tube, which has the following beneficial effects compared with the prior art:

[0021] 1. Since the cathode discharge part is always under a protective atmosphere composed of an emissive gas and / or a protective gas and does not contact air or oxygen, the cathode is not oxidized, ensuring its use without oxidation and reducing the product use cost.

[0022] 2. The cathode discharge tube in the present invention can generate light, plasma, corona, electroion, and arc simultaneously according to the use needs, improving the use scenarios and effects of the product.

[0023] 3. The cathode discharge part is designed into structures such as spiral, grid, hole, and strip, and the cathode shape is selected according to the discharge needs, thereby meeting the electron emission needs.

[0024] 4. A layer of electron emission material is coated on the surface of the cathode discharge part, which can generate a large number of electrons. The cathode has a high work function of electron emission and a high electron emission density, greatly improving the electron emission energy.

[0025] 5. By installing the cathode and the anode on different carriers respectively and separating the anode from the cathode with an insulating material, it is ensured that the cathode discharge part meets the usage requirements.

[0026] 6. By using a molybdenum sheet as a seal, due to its similar expansion coefficient to glass and quartz, it has excellent sealing performance under high-temperature conditions.

[0027] 7. Using a tungsten rod as the connecting part, it has excellent electrical conductivity and high-temperature stability. Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of an ionization device in the prior art.

[0029] Figure 2 is a schematic structural diagram of the present invention.

[0030] Figure 3 is a cross-sectional schematic of the present invention Figure 1 .

[0031] Figure 4 is a cross-sectional schematic of the present invention Figure 2 .

[0032] Figure 5 is a cross-sectional schematic of the present invention Figure 3 .

[0033] Figure 6 is a schematic structural diagram of the ionization device in the present invention.

[0034] Figure 7 is a schematic structural diagram of the plasma processing device in the present invention.

[0035] The reference numerals are: glass tube 11, anode 12, cathode 13, open end 14, cathode discharge tube 20, body part 21, cathode discharge part 22, connecting part 23, molybdenum sheet 25, anode 30, gas channel 40. Detailed Embodiments

[0036] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other instances, some well-known technical features are not described to avoid confusion with the present invention. Summary of the Invention

[0038] In the ionization device in the prior art, the cathode 13 and the anode 12 are located in the same cavity. Specifically, refer to the attached Figure 1, which is a cathode 13 discharge tube in the prior art, comprises a glass tube 11 with two open ends 14, and an anode 12 and a cathode 13 are arranged in the glass tube 11 with a predetermined gap. During use, the anode 12 and the cathode 13 are connected to a power source respectively, an ionization reaction is formed in the glass tube 11, and then oxygen is introduced into the open end 14, and oxygen is discharged to realize gas circulation, and oxygen molecules form ozone under the ionization effect.

[0039] However, the cathode 13 of the existing cathode 13 discharge tube will come into contact with air or oxygen, and the cathode 13 will be oxidized, causing the cathode 13 to be poisoned and a large amount of electrons to be lost. The cathode 13 has a low work function and a low density of emitted electrons, resulting in excessive power loss. Taking an ozone generator as an example, the ozone conversion efficiency of the emission cathode 13 is generally around 12% at the beginning. As the use time increases, the ozone conversion efficiency will decrease.

[0040] Therefore, the present invention proposes a cathode discharge tube 20, comprising: a main body 21, a cathode discharge part 22 and a connecting part 23. The main body 21 forms a closed hollow accommodation space, in which the accommodation space is filled with radioactive gas and / or protective gas; the cathode discharge part 22 is arranged in the accommodation space, wherein the cathode discharge part 22 is designed as a spiral structure, which increases the surface area of ​​the cathode discharge part 22, thereby increasing the number of electrons emitted, and a layer of electron emission material is coated on the surface of the cathode discharge part 22, which can generate a large number of electrons, and the cathode 13 has a high work function and a high density of emitted electrons, which greatly increases the amount of electron emission. One end of the connecting part 23 is exposed outside the main body 21, suitable for connecting to the negative pole of the power supply; the other end is sealed and passes through the main body 21, and is connected to the cathode discharge part 22. Since the cathode discharge portion 22 is always located in a protective atmosphere composed of an emitting gas and / or a protective gas and is not in contact with air or oxygen, the cathode discharge portion 22 is protected from oxidation, thereby extending the life of the emitting cathode 13 product and reducing the cost of using the product. Furthermore, light, plasma, corona, ions, and arcs can be generated simultaneously according to usage needs, thereby improving the use effect of the product and improving the usage scenarios and effects of the product.

[0041] The present invention will be further described below in conjunction with embodiments. The examples of the embodiments are intended to explain the present invention and should not be construed as limiting the present invention.

[0042] Embodiment 1

[0043] A cathode discharge tube 20 is used in an ozone generator, see the attached Figure 2 , Attachment Figure 3 The cathode discharge tube 20 includes: a main body 21, a cathode discharge portion 222, a connecting portion 23, and a molybdenum sheet 25.

[0044] The body part 21 is a quartz tube. The quartz tube has an elongated cylindrical shape with both ends being closed ends, forming an enclosed hollow accommodation space. A protective gas is filled in the accommodation space. The protective gas can be gases such as nitrogen, argon, krypton, xenon, tritium, helium, neon, argon, etc. For those skilled in the art, a mixed gas of various substances and a circulating substance can be filled according to the usage requirements, which will not be elaborated further here. The radioactive gas can select a suitable gas formula according to the usage needs and is used to form an electron beam. For those skilled in the art, the body part 21 is not limited to a quartz tube and can also be an ionization tube made of insulating materials such as a ceramic tube or a glass tube. In one embodiment, the length of the quartz tube is 177 mm and the diameter is 12.1 mm. For those skilled in the art, the size of the quartz tube is related to the electron output, and this size is not restrictive.

[0045] The cathode discharge part 22 is arranged inside the quartz tube, with a predetermined gap left between it and the tube wall. The length of the cathode discharge part 22 is determined along with the length of the quartz tube, generally suitable for 1 / 2 to 3 / 4 of the length of the quartz tube, and is far from the sealed end of the molybdenum sheet 25. The shape of the cathode discharge part 22 can be strip-shaped or filamentous. Preferably, in order to improve the discharge capacity of the cathode discharge tube 20, refer to the attached Figure 3 attachment Figure 4 , when designing the cathode discharge part 22 as a spiral structure, a mesh cylindrical shape, holes, strips, etc. formed by conductive wires. During actual use, the cathode shape is selected according to the discharge needs, so as to meet the electron emission needs, which can greatly increase the area of the cathode discharge part 22 and thus improve the electron output capacity. The conductive wire includes but is not limited to being made of materials such as iron, cobalt, tungsten, molybdenum, nickel, gold, silver, copper, carbon or their alloys.

[0046] One end of the connecting part 23 is exposed outside the body part 21 and is suitable for connecting to the negative pole of the power supply; the other end is sealed through the body part 21 and is connected to the cathode discharge part 22. The connecting part 23 is used to communicate with an external power supply. Since a large amount of heat is generated during discharge, the connection not only needs to have excellent electrical conductivity but also requires a certain degree of high-temperature stability. Preferably, the connecting part 23 is a tungsten rod. In order to further improve the discharge capacity of the cathode discharge part 22, refer to the attached Figure 5 , two connecting parts 23 are provided, respectively located on both sides of the cathode discharge part 22, connecting multiple power supplies in parallel with the cathode discharge part 22 to increase the electron density and electron output capacity of the cathode discharge part 22.

[0047] An electron emission material is coated on the outer surface of the cathode discharge part 22. In the prior art, there are also some examples of coating electron emission materials in low-voltage discharge devices. However, in high-voltage discharge devices, electron emission materials are generally not coated because, under high-temperature and high-pressure conditions, electron emission materials are prone to react with air and oxygen, causing the electron powder to be "poisoned" and a large amount of electrons to be lost. This not only fails to increase the electron emission density but also causes the discharge efficiency to rapidly decline over time. Taking an ozone generator as an example, the ozone conversion efficiency is about 12% at the beginning stage and will rapidly decline with the usage time. In this embodiment, since the cathode discharge part 22 is isolated from the external environment and is always under a protective atmosphere, the phenomenon of "poisoning" of the electron powder will not occur, which can effectively improve the discharge efficiency and increase the service life of the cathode 13. Taking an ozone generator as an example, an electron emission material mainly composed of strontium carbonate is coated on the outer surface of the cathode discharge part 22, and its ozone conversion rate can be increased from 8% in the prior art to 30%. Of course, for those skilled in the art, the electron emission material can also be barium carbonate, calcium carbonate, etc.

[0048] To further understand the technical solution of a cathode discharge tube 20 in this embodiment, a brief description of its application is given as follows: Taking an ozone generator as an example, when the cathode discharge tube 20 in the embodiment is applied to an ozone generator, refer to the appendix Figure 6 , a metal cover is sleeved outside the ionization tube to form an anode. A predetermined gap is left between the metal cover and the ionization tube to form a gas channel 40 for the flow of air or oxygen. Specifically, the metal cover is the anode 12 of the ionization device. When air or oxygen passes through the reserved space, ionization occurs to convert oxygen into ozone.

[0049] Embodiment 2

[0050] A cathode discharge tube is applied to a corona machine. The cathode discharge tube includes: a body part 21, a cathode discharge part 22, a connecting part 23, and a molybdenum sheet 25, and its structure is the same as that in Embodiment 1. In the corona machine, refer to the appendix Figure 7 , the cathode discharge tube is placed parallel to one side of the processing roller with a predetermined distance left. The processing roller is made of an insulating material and is grounded to form an anode 40. When the film passes through the roller, the cathode discharge tube forms a corona to roughen the surface of the film material, improve the surface tension of the material, and enable ink, glue, and paint to better adhere to the surface of the processed material.

[0051] Embodiment 3

[0052] A cathode discharge tube is applied to a plasma processing device. The cathode discharge tube includes: a body portion 21, a cathode discharge portion 22, a connecting portion 23, and a molybdenum sheet 25, and its structure is the same as that of Embodiment 1. In the plasma processing device, the cathode discharge tube and an anode 30 form a gas channel 40. Low-pressure gas passes through the gas channel 40, and these low-pressure gases are excited and ionized. These ionized electrons and particles with high energy react with the surface of the workpiece, achieving the effects of cleaning, activating, etching, and depositing the surface of the workpiece. These ionized gases with positive and negative particles are overall electrically neutral due to the balance of the total positive and negative charges. The new particles floating in the cavity generated after the reaction of this plasma with the surface of the workpiece will be pumped out of the vacuum cavity by a vacuum pump that continuously operates to maintain the vacuum degree in the cavity, that is, the microscopic pollutants generated during the low-temperature plasma processing will be continuously pumped out of the cavity by the vacuum pump.

[0053] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A cathode discharge tube, characterized in that, Comprising: A main body part that forms a closed hollow accommodation space, in which a radioactive gas and / or a protective gas is filled; A cathode discharge part that is arranged in the accommodation space, and an electron emission material is coated on the outer surface of the cathode discharge part; Two connecting parts that are respectively located on both sides of the cathode discharge part; one end of each connecting part is exposed outside the main body part and is adapted to be connected to the negative pole of a power supply, and the other end hermetically passes through the main body part and is connected to the cathode discharge part.

2. The cathode discharge tube according to claim 1, characterized in that, The cathode discharge part is a spiral, mesh, hole, strip structure or a combined structure formed by a conductive wire.

3. The cathode discharge tube according to claim 2, characterized in that, The conductive wire is made of iron, cobalt, tungsten, molybdenum, nickel, gold, silver, copper, carbon or an alloy material thereof.

4. The cathode discharge tube according to claim 1, characterized in that, The electron emission material at least includes one of barium carbonate, strontium carbonate and calcium carbonate.

5. The cathode discharge tube according to claim 1, characterized in that, The main body part is an ionization tube made of an insulating material.

6. The cathode discharge tube according to claim 5, characterized in that, The ionization tube is a ceramic tube, a glass tube or a quartz tube.

7. The cathode discharge tube according to claim 6, characterized in that, The main body part and the connecting part are hermetically connected through a molybdenum sheet.

8. The cathode discharge tube according to claim 1, characterized in that, The connecting part is a tungsten rod.

9. The cathode discharge tube according to claim 1, characterized in that, The protective gas is one or a mixed gas of nitrogen, argon, krypton, xenon, tritium, helium, neon, argon.

10. The cathode discharge tube according to claim 1, characterized in that, When the cathode discharge tube is in use, it can generate one or more reactions among light, plasma, corona, ions, and arc.

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