Heat insulation device of hollow cathode and hollow cathode

Abstract

The invention discloses a heat insulation device of a hollow cathode and the hollow cathode. The heat insulation device comprises a sleeve, a heat insulation assembly, a top cover and a base, the sleeve comprises an inner sleeve body and an outer sleeve body, a first cavity used for installing the heater assembly is defined between the inner circumferential walls of the inner sleeve body, and a second cavity used for installing the heat insulation assembly is formed between the inner sleeve body and the outer sleeve body. The other part of the lower end face of the heat insulation sleeve is sunken upwards to form a heat insulation interlayer used for clamping a heat insulation layer, a first gap is formed between the heat insulation sleeve and the inner sleeve, and a second gap is formed between the heat insulation sleeve and the outer sleeve. According to the technical scheme, through the arrangement of the two layers of heat insulation structures (the heat insulation sleeve and the heat insulation layer), heat of the heater assembly can be effectively isolated in the first cavity, heat exchange between the heater assembly and the outside is effectively reduced, the heat insulation efficiency of the heat insulation device is improved, the reliability of the hollow cathode is improved, and the power consumption of the hollow cathode is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of propulsion systems, and in particular to a heat insulation device for a hollow cathode and the hollow cathode. Background Art

[0002] Hollow cathodes are widely used in plasma discharge-related fields, such as surface treatment, vacuum coating, vacuum welding, etc. They can also be used as electron sources and neutralizers in aerospace electric propulsion systems. At present, most hollow cathodes used in electric propulsion systems are hot cathodes, and thermal insulation devices are key components of hollow cathodes.

[0003] In electric propulsion systems, after the heater heats the hollow cathode emitter to the desired temperature, the emitter emits electrons, which, after avalanche ionization, reduces the heating energy input. Thermal insulation in electric propulsion systems is used to minimize heat loss and maintain a constant temperature in the launch area. The thermal insulation capability of these devices directly impacts the launch performance and reliability of the hollow cathode. However, conventional thermal insulation systems are inefficient, resulting in excessively high heating power for the hollow cathode, which can severely lead to the hollow cathode becoming unsustainable and the thruster becoming inoperable.

[0004] In summary, how to improve the thermal insulation efficiency of thermal insulation devices is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a heat insulation device for a hollow cathode, which can improve the efficiency of thermal insulation.

[0006] The present invention also provides a hollow cathode comprising the above-mentioned heat insulation device.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A heat insulation device for a hollow cathode, comprising: a sleeve, a heat insulation component, a top cover and a base;

[0009] The sleeve includes an inner sleeve and an outer sleeve, wherein the inner circumferential wall of the inner sleeve forms a first cavity, and the outer circumferential wall of the inner sleeve and the inner circumferential wall of the outer sleeve form a second cavity, the first cavity is used to install the heater assembly, and the second cavity is used to install the thermal insulation assembly;

[0010] The top cover is mounted on the top end of the sleeve to close the top end of the second cavity, and the base is mounted on the bottom end of the sleeve to close the bottom end of the second cavity;

[0011] The thermal insulation assembly includes: a thermal insulation sleeve and a thermal insulation layer, wherein a portion of the lower end surface of the thermal insulation sleeve is used to be mounted on the base, and another portion of the lower end surface of the thermal insulation sleeve is recessed upward to form a thermal insulation interlayer, and the thermal insulation interlayer is used to sandwich the thermal insulation layer;

[0012] Wherein, a first gap is formed between the inner circumferential wall of the heat-insulating sleeve and the outer circumferential wall of the inner sleeve, and a second gap is formed between the outer circumferential wall of the heat-insulating sleeve and the inner circumferential wall of the outer sleeve.

[0013] Preferably, the axial dimension of the thermal insulation sleeve is smaller than the axial dimension of the second cavity, so that a third gap is formed between the upper end surface of the thermal insulation sleeve and the top cover.

[0014] Preferably, the size of the first gap is 1-2 mm.

[0015] Preferably, the size of the second gap is 0.3-1.5 mm.

[0016] Preferably, a fourth gap is formed between the top surface of the thermal insulation layer and the thermal insulation sleeve, and a fifth gap is formed between the bottom surface of the thermal insulation layer and the base.

[0017] Preferably, the radial dimension of the heat insulation layer is 1-2.5 mm, and the axial dimension of the heat insulation layer is 10-35 mm.

[0018] Preferably, the material of the heat insulation layer is a porous non-metallic material, and the pores of the porous non-metallic material are filled with granular high-temperature resistant material.

[0019] Preferably, the porous non-metallic material is aerogel.

[0020] Preferably, a portion of the lower end surface of the thermal insulation sleeve is mounted on the base by welding.

[0021] A hollow cathode comprises the above-mentioned heat insulation device.

[0022] It can be seen from the above technical solution that the thermal insulation device provided by the present invention can effectively isolate the heat of the heater assembly in the first cavity through the setting of two layers of thermal insulation structure (thermal insulation sleeve and thermal insulation layer), effectively reduce the heat exchange between the heater assembly and the outside world, improve the thermal insulation efficiency of the thermal insulation device, increase the reliability of the hollow cathode, and reduce the power consumption of the hollow cathode; and further provide a first gap between the thermal insulation sleeve and the inner sleeve, and provide a second gap between the thermal insulation sleeve and the outer sleeve, thereby further reducing the heat exchange between the heater assembly and the outside world, thereby improving the thermal insulation efficiency of the thermal insulation device.

[0023] The present invention further provides a hollow cathode, which has corresponding beneficial effects due to the adoption of the above-mentioned heat insulation device. For details, please refer to the above description, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A full cross-sectional view of a heat insulation device provided by an embodiment of the present invention;

[0026] Figure 2 A partial cross-sectional view of a thermal insulation device provided in an embodiment of the present invention.

[0027] The meanings of the reference numerals in the figures are as follows:

[0028] 1 is the top cover, 2 is the inner sleeve, 3 is the thermal insulation sleeve, 31 is the thermal insulation interlayer, 4 is the thermal insulation layer, 5 is the outer sleeve, 6 is the base, 7 is the first cavity, 8 is the second cavity, 9 is the first gap, 10 is the second gap, 11 is the third gap, 12 is the fourth gap, and 13 is the fifth gap. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The heat insulation device of the hollow cathode provided by the embodiment of the present invention is as follows: Figure 1 and Figure 2 As shown, it includes: a sleeve, a heat insulation component, a top cover 1 and a base 6;

[0031] The sleeve includes: an inner sleeve 2 and an outer sleeve 5. The inner circumferential wall of the inner sleeve 2 forms a first cavity 7, and the outer circumferential wall of the inner sleeve 2 and the inner circumferential wall of the outer sleeve 5 form a second cavity 8. The first cavity 7 is used to install a heater assembly, and the second cavity 8 is used to install a heat insulation assembly. The heater assembly includes but is not limited to a heater.

[0032] The top cover 1 is mounted on the top of the sleeve to close the top of the second cavity 8, and the base 6 is mounted on the bottom of the sleeve to close the bottom of the second cavity 8;

[0033] The thermal insulation assembly includes: a thermal insulation sleeve 3 and a thermal insulation layer 4. A portion of the lower end surface of the thermal insulation sleeve 3 is used to be mounted on the base 6. Another portion of the lower end surface of the thermal insulation sleeve 3 is recessed upward to form a thermal insulation interlayer 31. The thermal insulation interlayer 31 is used to sandwich the thermal insulation layer 4.

[0034] A first gap 9 is formed between the inner circumferential wall of the thermal insulation sleeve 3 and the outer circumferential wall of the inner sleeve 2 , and a second gap 10 is formed between the outer circumferential wall of the thermal insulation sleeve 3 and the inner circumferential wall of the outer sleeve 5 .

[0035] In the above technical solution, compared with the prior art, by setting up a two-layer thermal insulation structure (the thermal insulation sleeve 3 and the thermal insulation layer 4), the heat of the heater assembly can be effectively isolated in the first cavity 7, effectively reducing the heat exchange between the heater assembly and the outside world, improving the thermal insulation efficiency of the thermal insulation device, increasing the reliability of the hollow cathode, and reducing the power consumption of the hollow cathode; and by providing a first gap 9 between the thermal insulation sleeve 3 and the inner sleeve 2, and a second gap 10 between the thermal insulation sleeve 3 and the outer sleeve 5, the heat exchange between the heater assembly and the outside world is further reduced, thereby improving the thermal insulation efficiency of the thermal insulation device.

[0036] In an optional embodiment, the axial dimension of the thermal insulation sleeve 3 is smaller than the axial dimension of the second cavity 8, so that a third gap 11 is formed between the upper end surface of the thermal insulation sleeve 3 and the top cover 1, so that the thermal insulation sleeve 3 and the top cover 1 do not contact each other, further avoiding heat conduction and loss.

[0037] In order to make the structure of the thermal insulation device compact and avoid heat conduction loss, the size of the first gap 9 is 1-2 mm; in actual production needs, the size of the first gap 9 can be adjusted to facilitate effective control of the heat radiation efficiency between the thermal insulation sleeve 3 and the inner sleeve 2.

[0038] In order to further make the structure of the thermal insulation device compact and avoid heat conduction loss, the size of the second gap 10 is 0.3-1.5 mm. In actual production needs, the size of the second gap 10 can be adjusted to effectively control the heat radiation efficiency between the thermal insulation sleeve 3 and the outer sleeve 5.

[0039] In an optional embodiment, if Figure 2As shown, the top surface of the thermal insulation layer 4 and the thermal insulation sleeve 3 form a fourth gap 12, and the bottom surface of the thermal insulation layer 4 and the base 6 form a fifth gap 13. The setting of the fourth gap 12 reduces the contact area between the thermal insulation layer 4 and the thermal insulation sleeve 3, reducing heat conduction between the two. The fifth gap 13 avoids heat conduction between the thermal insulation layer 4 and the base 6, thereby improving the thermal insulation efficiency. It should be noted that the axial dimension of the thermal insulation layer 4 is smaller than the axial dimension of the thermal insulation interlayer 31. Preferably, the thermal insulation layer 4 is in partial contact with the thermal insulation sleeve 3 radially to reduce heat conduction. In addition, the specific dimensions of the fourth gap 12 and the fifth gap 13 can be adjusted according to actual needs.

[0040] The above technical solution is optimized, and the radial dimension of the heat insulation layer 4 is 1-2.5 mm, and the axial dimension of the heat insulation layer 4 is 10-35 mm, which ensures the heat insulation efficiency of the heat insulation device while also ensuring a compact structure.

[0041] To optimize the above technical solution, the material of the thermal insulation layer 4 is a porous non-metallic material, and the pores of the porous non-metallic material are filled with granular high-temperature resistant material, so that the thermal insulation layer 4 has the advantage of high temperature resistance; preferably, the granular high-temperature resistant material is graphite or silicon carbide.

[0042] To further optimize the above technical solution, the porous non-metallic material is aerogel. The thermal conductivity of aerogel is extremely low, only 0.12w / (mk), which has good thermal insulation performance and reduces energy exchange. At the same time, aerogel is an industrial part, which is conducive to reducing costs.

[0043] In an optional embodiment, a portion of the lower end surface of the thermal insulation sleeve 3 is mounted on the base 6 by welding. The welding method can make the structure more stable. Preferably, welding includes but is not limited to spot welding, electron beam welding, argon arc welding, laser welding and the like. It should be noted that electron beam welding is used between the thermal insulation sleeve 3 and the base 6, which can effectively control the gap between the thermal insulation sleeve 3 and the thermal insulation layer 4, and also ensure the gap between the thermal insulation sleeve 3 and the inner sleeve 2 and the outer sleeve 5 respectively, which is conducive to reducing the area of ​​heat transfer. After the aerogel is placed in the thermal insulation interlayer 31, the thermal insulation efficiency of the inner and outer layers is greatly increased (the inner and outer layers refer to the thermal insulation sleeve 3 and the thermal insulation layer 4).

[0044] The present invention also provides a hollow cathode, comprising: the above-mentioned active heat insulation device. Since this solution adopts the above-mentioned heat insulation device, it also has corresponding beneficial effects. For details, please refer to the above description and will not be repeated here.

[0045] The technical features mentioned above, the technical features described below, and the technical features shown individually in the accompanying drawings may be combined arbitrarily, as long as the combined technical features do not conflict with each other. All possible feature combinations are technical contents explicitly described in this document. Any of the multiple sub-features included in the same statement can be applied independently and does not necessarily have to be applied in conjunction with the other sub-features.

[0046] The present invention will be further described below with reference to specific embodiments:

[0047] This thermal insulation device can be used in the field of aerospace propulsion systems, including an inner sleeve 2, an outer sleeve 5 and a thermal insulation component. The thermal insulation layer 4 of the thermal insulation component further reduces the heat transfer efficiency due to its own low thermal conductivity, further effectively reducing the heat exchange between the heater and the outside world, thereby improving the thermal insulation efficiency of the hollow cathode thermal insulation device, increasing the reliability of the hollow cathode, and reducing the power consumption of the hollow cathode.

[0048] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0049] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hollow cathode insulation device, characterized in that: include: Sleeve, thermal insulation assembly, top cover (1) and base (6); The sleeve comprises: an inner sleeve (2) and an outer sleeve (5); a first cavity (7) is formed between the inner circumferential walls of the inner sleeve (2); a second cavity (8) is formed between the outer circumferential wall of the inner sleeve (2) and the inner circumferential wall of the outer sleeve (5); the first cavity (7) is used to install the heater assembly, and the second cavity (8) is used to install the heat insulation assembly; The top cover (1) is mounted on the top end of the sleeve and is used to close the top end of the second cavity (8); the base (6) is mounted on the bottom end of the sleeve and is used to close the bottom end of the second cavity (8); The thermal insulation assembly comprises: a thermal insulation sleeve (3) and a thermal insulation layer (4); a portion of the lower end surface of the thermal insulation sleeve (3) is used for mounting on the base (6); another portion of the lower end surface of the thermal insulation sleeve (3) is recessed upward to form a thermal insulation interlayer (31); and the thermal insulation interlayer (31) is used for clamping the thermal insulation layer (4); The inner peripheral wall of the heat-insulating sleeve (3) and the outer peripheral wall of the inner sleeve (2) form a first gap (9), and the outer peripheral wall of the heat-insulating sleeve (3) and the inner peripheral wall of the outer sleeve (5) form a second gap (10).

2. The thermal insulation device according to claim 1, characterized in that The axial dimension of the heat-insulating sleeve (3) is smaller than the axial dimension of the second cavity (8), so that a third gap (11) is formed between the upper end surface of the heat-insulating sleeve (3) and the top cover (1).

3. The thermal insulation device according to claim 2, characterized in that The size of the first gap (9) is 1-2 mm.

4. The thermal insulation device according to claim 3, characterized in that The size of the second gap (10) is 0.3-1.5 mm.

5. The thermal insulation device according to any one of claims 1 to 4, characterized in that: The top surface of the thermal insulation layer (4) and the thermal insulation sleeve (3) form a fourth gap (12), and the bottom surface of the thermal insulation layer (4) and the base (6) form a fifth gap (13).

6. The thermal insulation device according to claim 5, characterized in that The radial dimension of the heat insulation layer (4) is 1-2.5 mm, and the axial dimension of the heat insulation layer (4) is 10-35 mm.

7. The thermal insulation device according to claim 5, characterized in that The material of the heat insulation layer (4) is a porous non-metallic material, and the pores of the porous non-metallic material are filled with granular high-temperature resistant material.

8. The thermal insulation device according to claim 7, characterized in that The porous non-metallic material is aerogel.

9. The thermal insulation device according to claim 1, characterized in that A portion of the lower end surface of the heat-insulating sleeve (3) is mounted on the base (6) by welding.

10. A hollow cathode, characterized in that: include: The thermal insulation device according to any one of claims 1 to 9.

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