Double-layer electromagnetic shielding cabinet with isolated inner layer

Abstract

The utility model relates to a double-layer electromagnetic shielding cabinet with an inner layer isolated from the ground, and solves the technical problems that an existing electromagnetic shielding cabinet is few in grounding selection, poor in shielding effect of an inner layer shielding box body, free of filtering in power supply, large in occupied space of a shielding door, and poor in heat dissipation of an interlayer between the inner layer shielding box body and the outer layer shielding box body. The shielding box comprises an inner-layer shielding box body provided with an inner-layer shielding door, an outer-layer shielding box body provided with an outer-layer shielding door, an insulating supporting block arranged between the inner-layer shielding box body and the outer-layer shielding box body, a cable switching disc and a power supply filter which are arranged on the inner-layer shielding box body, and a waveguide window and a grounding column which are arranged on the outer-layer shielding box body, the inner-layer shielding box body and the outer-layer shielding box body are electrically isolated, a moisture-proof insulating supporting block is filled between the inner-layer shielding box body and the outer-layer shielding box body, and a filtering design is added And shielding of complex electromagnetic signals and isolation of the external environment are realized through the cable switching disc and the waveguide tube.

Description

Technical Field

[0001] The utility model relates to an electromagnetic shielding device, in particular to a double-layer electromagnetic shielding cabinet with an inner layer ground isolation. Background Art

[0002] When conducting special experiments such as electromagnetic experiments and other scientific research, electromagnetic shielding cabinets often face many problems, such as complex and changeable electromagnetic environments. As experimental requirements change, the requirements for electromagnetic shielding cabinets are also constantly increasing. In order to ensure that the data obtained is safe, true and reliable, it is necessary to ensure the normal and stable operation of instruments and equipment, so the electromagnetic shielding cabinet needs to be reliable.

[0003] To ensure the reliability of the electromagnetic shielding cabinet, first of all, the electromagnetic shielding cabinet needs to have high safety and reliability to ensure that the instruments and equipment can be safely placed and work stably under special experimental conditions. This requires the electromagnetic shielding cabinet to have high structural strength and environmental adaptability; secondly, the electromagnetic shielding cabinet needs to have good electromagnetic shielding function to reduce the impact of external electromagnetic interference on internal instruments and equipment; in addition, since the grounding methods of different instruments and equipment may be different, the electromagnetic shielding cabinet needs to provide a variety of grounding options.

[0004] As the demand for special experiments gradually increases, researchers have begun to use double-layer electromagnetic shielding cabinets with better electromagnetic shielding performance. Double-layer electromagnetic shielding cabinets are made up of two layers of electromagnetic shielding cabinets, the inner and outer layers, and the instruments and equipment are installed on the equipment bracket of the inner shielding cabinet. Compared with single-layer electromagnetic shielding cabinets, double-layer electromagnetic shielding cabinets can ensure that when the outer shielding cabinet forms a Faraday cage and is grounded, the inner shielding cabinet can be floated or connected to an external transmission line to connect to the interference-free ground, achieving better electromagnetic shielding and moisture-proof effects.

[0005] However, in actual use, the existing double-layer electromagnetic shielding cabinet has the following problems:

[0006] (1) The cable interfaces of the inner and outer shielding boxes are connected to each other. When an armored cable (a cable with a shielding layer on the surface) is introduced from the outside as a signal transmission line, the armor of the armored cable is connected to the cable interface of the inner shielding box after contacting the outer shielding box, resulting in direct connection between the inner and outer shielding boxes. This makes it impossible for the actual electromagnetic shielding efficiency of the inner shielding box to achieve the ideal effect. In fact, it only has the shielding effect of a single-layer electromagnetic shielding cabinet, and it is impossible to provide a variety of grounding schemes for internal instruments and equipment;

[0007] (2) There is no filtering design in the power supply system, which cannot provide stable power supply for sensitive instruments and equipment in complex electromagnetic environments;

[0008] (iii) The heat dissipation effect between the inner and outer shielding boxes is poor. When the equipment installed in the inner shielding box is unattended, the heat generated cannot be discharged in time, which will cause it to be unable to work for a long time and easily cause overheating problems. If an electric-driven fan is used in the outer shielding box for heat dissipation, it is necessary to open holes in the inner shielding box for lead wires, which will increase the difficulty of power supply design of the electromagnetic shielding cabinet in a complex electromagnetic environment and reduce the effect of electromagnetic shielding.

[0009] (IV) Shield doors that are generally hinged and open single-door are heavy and bulky. When opened, they take up a lot of space and are difficult to operate, making it difficult for experimental personnel to carry out work in a limited space. Utility Model Content

[0010] The purpose of the utility model is to solve the technical problems of the existing electromagnetic shielding cabinets, such as few grounding options, poor shielding effect of the inner shielding box, no filtering of the power supply, large space occupied by the shielding door, and poor heat dissipation of the interlayer between the inner and outer shielding boxes, and to provide a double-layer electromagnetic shielding cabinet with inner ground isolation.

[0011] In order to achieve the above purpose, the technical solutions provided by the utility model are as follows:

[0012] A double-layer electromagnetic shielding cabinet with inner ground isolation comprises an outer shielding box and an inner shielding box embedded in the outer shielding box, an outer shielding door is arranged on one side of the outer shielding box, and an inner shielding door is arranged on the side of the inner shielding box corresponding to the outer shielding door. The cabinet is special in that:

[0013] Definition: The outer shielding box has one side with an outer shielding door as the front surface and the lower side as the bottom surface. Among the remaining sides of the outer shielding box except the front surface and the bottom surface, two sides are respectively provided with waveguide windows, and the two waveguide windows are connected through the gap between the outer shielding box and the inner shielding box;

[0014] The outer shielding door and the inner shielding door are both shielding doors of slot-type structure, and the contact parts with the outer shielding box or the inner shielding box are installed with beryllium bronze finger-type springs; the upper sides of the front of the outer shielding box and the inner shielding box are provided with corresponding slots, and the outer shielding door and the inner shielding door are respectively snapped into the corresponding slots;

[0015] A waveguide is provided on the outer shielding box under the outer shielding door, which is used to transfer external cables into the outer shielding box; a cable transfer tray is provided on the inner shielding box under the inner shielding door, which is used to transfer cables into the inner shielding box to connect instruments and equipment, and the cable transfer tray is insulated from the inner shielding box;

[0016] The outer shielding box and the inner shielding box are insulated by a plurality of insulating support blocks, which are used to cooperate with the cable adapter plate to realize the nesting of two Faraday cages formed by the outer shielding box and the inner shielding box;

[0017] The inner shielding box is provided with a partition fixing bracket inside for fixing instruments and equipment, and PDU socket strips are provided on both sides for powering the instruments and equipment. A camera bracket and a lighting device are provided near the top surface. The camera bracket is used to install a camera for monitoring inside the cabinet, and the power supply cables of the camera and the lighting device are connected to the PDU socket strip;

[0018] A power supply filter is provided on the outer surface of the inner shielding box, the input end of the power supply filter is used to connect with the power supply cable passing through the waveguide and connected to the power supply, and the output end is used to connect with the power supply cable passing through the cable adapter tray and connected to the PDU socket strip;

[0019] A grounding column is arranged on the bottom surface of the outer shielding box.

[0020] Furthermore, the cable adapter tray is a rectangular plate on which a cable adapter with a through-hole structure is provided for connecting the cables to the internal instruments and equipment;

[0021] The cable switching tray is provided with at least one cable switching waveguide, which is used for switching insulating transmission lines such as optical fibers to avoid losses such as light attenuation when switching through the cable adapter.

[0022] Furthermore, the waveguide on the outer shielding box is provided with an extension interface for externally connecting a corrugated tube filled with a good conductor material to improve the electromagnetic shielding effect, impact resistance and moisture resistance;

[0023] Metal blind covers are installed on the outer end interfaces of the waveguides on the outer shielding box and the cable adapter plate to shield the unused spare waveguides.

[0024] Furthermore, the insulating support block is made of insulating ceramic support material, and the outer surface is covered with thermally conductive insulating silica gel to assist in heat conduction;

[0025] A plurality of insulating support blocks are respectively located between the gaps on the sides of the outer shielding box and the inner shielding box except the front side.

[0026] Furthermore, the two waveguide windows are respectively located on the back and top of the outer shielding box body, the waveguide window located on the back is higher than the insulating support block in the back gap, and the waveguide window located on the top is arranged closer to the back than the insulating support block in the top gap.

[0027] Furthermore, the waveguide 5 is made of the same material as the outer shielding box and is welded to the outer shielding box.

[0028] Furthermore, four fixable rollers are arranged on the bottom surface of the outer shielding box body, and four hanging rings are arranged on the top surface.

[0029] Furthermore, the thickness of the insulating support block is 8 cm, and the length and width are 15 cm;

[0030] The thickness of the thermally conductive insulating silicone is 0.5 cm;

[0031] The insulating support blocks located in the gaps on the back, left and right sides are respectively located in the middle of the sides and are provided with two at an interval of 30 cm;

[0032] There are nine insulating support blocks located in the bottom surface gap, which are evenly distributed in the bottom surface gap;

[0033] The front gap between the outer shielding box and the inner shielding box is also filled with an insulating support block to make the gap smooth.

[0034] Furthermore, the lighting device includes an LED lamp and a switch thereof.

[0035] Furthermore, the specifications of the power supply filter are rated voltage 220AC, operating frequency 50 / 60Hz, maximum current 32A, and electromagnetic shielding effectiveness 100dB@(1MHz-10GHz); it can also be a power supply filter of other specifications that meet the experimental conditions.

[0036] Compared with the prior art, the utility model has the following beneficial effects:

[0037] 1. The utility model provides a double-layer electromagnetic shielding cabinet with inner ground isolation, which adopts a design in which the inner and outer boxes are insulated from each other, and realizes the nesting of two complete Faraday cages through multiple insulating support blocks and insulating cable adapter plates; the double-layer shielding box improves the electromagnetic shielding efficiency, and the nesting design can improve the insulation, moisture-proof and shielding capabilities of the inner shielding box; the cable adapter plate of the inner shielding box and the inner shielding box are insulated, and the electromagnetic cannot be coupled to the inner shielding box through the cable, which effectively utilizes the shielding design of the double-layer shielding box; based on this, multiple grounding of equipment in the cabinet is realized, and the inner shielding box is completely isolated from the ground, providing good experimental conditions for various types of tests, solving the problem of few grounding options for electromagnetic shielding cabinets, and improving the electromagnetic shielding effect of the electromagnetic shielding cabinet, which can achieve an electromagnetic shielding efficiency greater than or equal to 100dB@(14KHz~10GHz).

[0038] 2. The utility model provides a double-layer electromagnetic shielding cabinet with an inner layer isolated from the ground. Through the design of the waveguide window, while ensuring the shielding effectiveness, air convection will be formed between the inner and outer shielding box interlayers to achieve passive cooling of internal instruments and equipment. The heat dissipation effect is good and it is suitable for stable operation of high-power instruments and equipment. It can enable the instruments and equipment inside the electromagnetic shielding cabinet to operate for a long time without supervision; at the same time, it avoids relying on insulating thermal conductive materials to fill the interlayer for heat dissipation and increase costs.

[0039] 3. The utility model provides a double-layer electromagnetic shielding cabinet with inner ground isolation. In order to facilitate the opening and closing of the door in limited space operations, a slot-type shielding door is adopted. Compared with the existing hinged shielding door, the door body is lighter and occupies less space after opening the door, which is more convenient for equipment debugging in limited experimental space.

[0040] 4. The utility model provides a double-layer electromagnetic shielding cabinet with an inner ground isolation. A power supply filtering design is added to the power supply system of the electromagnetic shielding cabinet, and a power supply filter is installed on the side wall of the inner shielding box, which solves the problem of electromagnetic coupling to the power supply line affecting the normal operation of the equipment and meets the stable power supply requirements for sensitive instruments and equipment in complex electromagnetic environments.

[0041] 5. The utility model provides a double-layer electromagnetic shielding cabinet with an inner ground isolation, and designs a monitoring camera installation position and an LED lighting device inside the cabinet to facilitate monitoring and operation of the cabinet.

[0042] 6. The utility model provides a double-layer electromagnetic shielding cabinet with an inner layer isolated from the ground. It effectively dissipates heat through waveguide windows, isolates the inner and outer layers through insulating support blocks and insulating cable adapter trays, and enables stable operation of sensitive electronic equipment by adding a power supply filtering design. The above designs are combined to enable the double-layer electromagnetic shielding cabinet to achieve long-term and stable operation of instruments and equipment, and achieve better electromagnetic shielding efficiency, which can meet the needs of electromagnetic experiments in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of a double-layer electromagnetic shielding cabinet with inner ground isolation of the utility model;

[0044] Figure 2 It is a schematic diagram of the three-dimensional structure of the embodiment of the utility model after the outer shielding door is disassembled;

[0045] Figure 3 It is a schematic diagram of the three-dimensional structure of the embodiment of the utility model after the outer shielding door and the inner shielding door are disassembled;

[0046] Figure 4 It is a schematic diagram of the position of the waveguide window on the outer shielding box in the embodiment of the utility model;

[0047] Figure 5 It is a schematic diagram of the structure between the inner shielding box and the outer shielding box in the embodiment of the utility model (the outer shielding box is a cross-sectional view);

[0048] Figure 6 It is a structural schematic diagram of a cable adapter tray in an embodiment of the utility model;

[0049] Figure 7 It is a schematic diagram of the card slot structure of the outer shielding box in the embodiment of the utility model;

[0050] Figure 8 It is a schematic structural diagram of the outer shielding door in an embodiment of the utility model.

[0051] The following are the descriptions of the accompanying figures:

[0052] 1-Outer shielding box; 2-Inner shielding box; 3-Outer shielding door; 4-Inner shielding door; 5-Waveguide tube; 6-Cable transfer tray; 7-Power supply filter; 8-Partition fixing bracket; 9-Camera bracket; 10-Lighting device; 11-Waveguide window; 12-Lifting ring; 13-Fixable roller; 14-Insulating support block; 15-Grounding column; 16-Cable adapter; 17-Cable transfer waveguide tube. DETAILED DESCRIPTION

[0053] The specific technical solutions in the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0054] It should be noted that the design directional indications in this embodiment (such as up, down, top, bottom, inside, outside, back, etc.) are only used to explain the relative position relationship between the components in a certain posture (as shown in the drawings) to facilitate the description of the utility model, and do not indicate that the parts must have a specific orientation.

[0055] Figure 1 The utility model provides a double-layer electromagnetic shielding cabinet with inner ground isolation. The main structure of the double-layer cabinet is composed of an outer shielding box 1 and an inner shielding box 2. The inner shielding box 2 is embedded in the outer shielding box 1. The gap between the outer shielding box 1 and the inner shielding box 2 is filled with an insulating support block 14 to support the inner shielding box.

[0056] refer to Figure 5, the insulating support block 14 is made of insulating ceramic support material, and the outer surface is covered with thermally conductive insulating silicone to assist heat conduction; the thickness of the insulating support block 14 is 8cm, the length and width are both 15cm, and the thickness of the thermally conductive insulating silicone is 0.5cm; the insulating support blocks located in the back, left and right gaps are respectively located in the middle of the surface and are set at an interval of 30cm. There are nine insulating support blocks located in the bottom gap, which are evenly distributed in the bottom gap; an insulating support block 14 is also provided between the front gap of the outer shielding box 1 and the inner shielding box 2 to make the interlayer gap smooth and aesthetically pleasing;

[0057] The insulation support 14 between the outer shielding box 1 and the inner shielding box 2 is reasonably arranged under the premise of ensuring strength and insulation performance, and the weight is controlled by reducing the laying area of ​​the insulation material; the interlayer spacing between the inner and outer shielding boxes is 80mm, and after testing, it can be guaranteed that the insulation resistance is greater than or equal to 100MΩ@1000V;

[0058] refer to Figure 3 A partition fixing bracket 8 is arranged inside the inner shielding box 2, and an instrument partition is installed on the partition fixing bracket 8 to place instruments and equipment; an LED lamp and its switch (illumination device 10) and a camera bracket 9 are arranged on the inner side of the inner shielding box 2 near the top, which are used to monitor the long-term operation of the cabinet under unattended operation; PDU socket strips are fixed on the side panels on both sides of the inner shielding box 2 for power supply of instruments and equipment; the power supply cables of the LED lamp and the camera are connected to the PDU socket strip;

[0059] refer to Figure 2 , Figure 6 A cable transfer tray 6 is provided on the front of the inner shielding box 2. The cable transfer tray 6 is a rectangular metal plate on which a cable adapter 16 with a through-hole structure is provided, so that the introduced cables are transferred to the instrument equipment through the cable adapter 16 for data transmission; two cable transfer waveguides 17 are provided on the cable transfer tray 6 for transferring optical fibers to avoid optical attenuation when the optical fibers are transferred through the cable adapter; the flange on the cable transfer tray 6 is fixed to the inner shielding box 2 by insulating nylon screws, and the cable transfer tray 6 is connected to the inner shielding box 2. The inner shielding box 2 is isolated by insulating rubber, and the cable adapter and the inner shielding box 2 are completely insulated; based on the design of the cable adapter plate 6 and the insulating support block 14, the ground of the instrument and equipment inside the inner shielding box 2 can be short-circuited with the inner shielding box 2 to achieve floating ground, and completely isolated from the external electromagnetic environment, or it can be transferred to the external and remote independent ground connection through the cable adapter 16, or it can be transferred to the external and connected to the terminal 15 through the cable adapter 16;

[0060] Cables refer to data cables such as electrical cables and optical fibers, and power cables;

[0061] A power supply filter 7 is provided on the outside of the inner shielding box 2, on the left side surface of the cable adapter tray 6. The rated voltage of the power supply filter is 220AC, the operating frequency is 50 / 60Hz, the maximum current is 32A, and the electromagnetic shielding effectiveness of the filter is 100dB@(1MHz-10GHz); the output end of the power supply filter is connected to the PDU socket through the power supply cable passing through the cable adapter tray;

[0062] A manual shielding door (inner shielding door 4) is arranged on the front of the inner shielding box 2, and a manual shielding door (outer shielding door 3) is arranged on the front of the outer shielding box 1. The contact parts between the manual shielding door and the outer shielding box 1 or the inner shielding box 2 are all installed with beryllium bronze finger-shaped springs; corresponding card slots are arranged on the upper positions of the front of the outer shielding box 1 and the inner shielding box 2, and the outer shielding door 3 and the inner shielding door 4 are respectively connected to the corresponding card slots; compared with the hinged shielding door, it is light in weight and occupies less space after opening the door, which is more convenient for equipment debugging in limited experimental space;

[0063] The outer shielding box 1 is made of 2mm steel plate, which is electroplated with zinc and fully welded. The inner shielding box 2 is made of 3mm steel plate, which is electroplated with copper and fully welded. The movable parts of the two manual shielding doors are equipped with beryllium bronze finger-shaped springs to form a complete Faraday cage structure, and are equipped with handles on both sides.

[0064] refer to Figure 7-8 The outer shielding box 1 is provided with a card slot, and its specific structure is a rectangular groove surrounded by two rectangular ring plates of different sizes, which are perpendicular to the front of the outer shielding box 1 and face outward; a beryllium bronze finger-type spring is installed in the rectangular groove; the outer shielding door 3 is a rectangular plate that can be clipped, and its specific structure is that the four sides of the rectangular plate are provided with rectangular card plates that are perpendicular to the rectangular plate and face inward and cooperate with the rectangular groove; for easy disassembly, a handle can be provided on the outer surface of the outer shielding door 3; similarly, the structures of the inner shielding box 2 and the inner shielding door 4 are the same.

[0065] refer to Figure 4 , square holes are provided on the top and back of the outer shielding box 1, and waveguide windows 11 are installed respectively, and the two waveguide windows 11 are connected through the gap between the inner and outer boxes; the inner shielding box 2 will generate high temperature due to the operation of the equipment, which will cause the air temperature of the inner and outer shielding box interlayers to rise, resulting in a temperature difference and pressure difference between the interlayer and the external environment; through the design of the waveguide windows 11, while ensuring the shielding effectiveness, air convection can be formed between the cabinet gaps, so that the external low-temperature air can flow through the two waveguide windows 11, so as to achieve the purpose of passive heat dissipation;

[0066] Five waveguides 5 with metal blind covers are installed at the middle and lower part of the front of the outer shielding box 1. The same material as the outer shielding box 1 is selected and welded on its surface. The metal blind covers are used to shield the remaining unconnected waveguides; the waveguide 5 is designed with a radius / length ≥ 1:10, which can ensure that the electromagnetic signal strength attenuation within the cut-off frequency range is greater than 100dB;

[0067] The waveguide 5 on the outer shielding box 1 is provided with an extension interface, which can be externally connected to a seamless stainless steel bellows. The inside of the longer bellows can be filled with benign conductor materials such as copper wool, which can not only produce a good electromagnetic shielding effect, but also has good impact resistance and moisture resistance, and can better protect the cables or optical cables connected to the electromagnetic shielding cabinet;

[0068] The external transmission cable / optical fiber passes through the corrugated tube and waveguide 5 and is connected to the instrument through the cable adapter 16 or the cable adapter waveguide 17 on the cable adapter tray 6;

[0069] The external power supply cable is connected from the power supply, passes through the corrugated tube and the waveguide 5, and is connected to the input end of the power supply filter 7;

[0070] A grounding post 15 is installed at the bottom of the outer shielding box 1 for local grounding of the cabinet;

[0071] Four fixed rollers 13 are installed at the bottom of the outer shielding box 1 for pushing and moving the cabinet or forklift transportation; four lifting rings 12 are installed at the top of the outer shielding box for lifting.

[0072] In the embodiment of the utility model, the inner and outer shielding boxes are insulated by interlayers and nested with each other, realizing the nesting of two complete Faraday cages, and based on this, multiple grounding of the equipment in the cabinet is realized. Among them, the cable adapter plate of the inner shielding box is treated with insulation between the inner shielding box, and the electromagnetic will not be coupled to the inner shielding box through the cable, realizing the complete isolation of the inner shielding box, providing good experimental conditions for various types of tests, which is of great significance for the survival and stable operation of instruments and equipment under harsh working conditions.

[0073] In the embodiment of the utility model, under the premise of not affecting the shielding effectiveness, two waveguide windows of the outer shielding box are used to achieve simple and effective heat dissipation, so that the electromagnetic shielding cabinet can be suitable for stable operation of higher power equipment, reducing the power supply complexity of the cabinet and improving the reliability of the cabinet.

[0074] The above content is only an embodiment of the present utility model and is not intended to limit the protection scope of the present utility model. Any equivalent structural transformations made using the contents of the present utility model specification and drawings, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present utility model.

Claims

1. A double-layer electromagnetic shielding cabinet with inner ground isolation, comprising an outer shielding box (1) and an inner shielding box (2) embedded in the outer shielding box (1), an outer shielding door (3) being arranged on one side of the outer shielding box (1), and an inner shielding door (4) being arranged on the side of the inner shielding box (2) corresponding to the outer shielding door (3), characterized in that: Definition: The outer shielding box (1) is provided with an outer shielding door (3), one side of which is the front surface and the lower side is the bottom surface, then among the remaining sides of the outer shielding box (1) except the front surface and the bottom surface, two side surfaces are respectively provided with waveguide windows (11), and the two waveguide windows (11) are connected through the gap between the outer shielding box (1) and the inner shielding box (2); The outer shielding door (3) and the inner shielding door (4) are both shielding doors of a slot-type structure, and the contact parts with the outer shielding box (1) or the inner shielding box (2) are both equipped with beryllium bronze finger-shaped springs; the upper sides of the front faces of the outer shielding box (1) and the inner shielding box (2) are provided with corresponding slots, and the outer shielding door (3) and the inner shielding door (4) are respectively snapped into the corresponding slots; The outer shielding box (1) below the outer shielding door (3) is provided with a waveguide (5) for transferring external cables to the outer shielding box (1); the inner shielding box (2) below the inner shielding door (4) is provided with a cable transfer tray (6) for transferring cables to the inner shielding box (2) for connecting instruments and equipment, and the cable transfer tray (6) is insulated from the inner shielding box (2); The outer shielding box (1) and the inner shielding box (2) are insulated by a plurality of insulating support blocks (14), and are used to cooperate with the cable adapter plate (6) to achieve the nesting of two Faraday cages formed by the outer shielding box (1) and the inner shielding box (2); The inner shielding box (2) is provided with a partition fixing bracket (8) for fixing instruments and equipment, and PDU socket strips are provided on both sides for powering the instruments and equipment. A camera bracket (9) and a lighting device (10) are provided near the top surface. The camera bracket (9) is used to install a camera to monitor the inside of the cabinet, and the power supply cables of the camera and the lighting device (10) are connected to the PDU socket strip. The outer surface of the inner shielding box (2) is provided with a power supply filter (7), the input end of the power supply filter (7) is used to be connected to a power supply cable passing through the waveguide (5) and connected to a power source, and the output end of the power supply filter (7) is used to be connected to a power supply cable passing through a cable adapter plate (6) and connected to a PDU socket strip; A grounding column (15) is provided on the bottom surface of the outer shielding box (1).

2. According to claim 1, a double-layer electromagnetic shielding cabinet with inner layer isolation is characterized in that: The cable adapter plate (6) is a rectangular plate on which a cable adapter (16) with a through-hole structure is provided for connecting cables to internal instruments and equipment; The cable switching tray (6) is provided with at least one cable switching waveguide tube (17) for switching optical fibers to avoid light attenuation when the optical fibers are switched through the cable adapter (16).

3. According to claim 2, a double-layer electromagnetic shielding cabinet with inner layer isolation is characterized in that: The waveguide tube (5) on the outer shielding box (1) is provided with an extension interface for externally connecting a corrugated tube filled with a conductive material to improve the electromagnetic shielding effect, impact resistance and moisture resistance; The outer end interfaces of the waveguide tubes (5) on the outer shielding box (1) and the cable adapter plate (6) are installed with metal blind covers for shielding unused free waveguide tubes.

4. According to claim 3, a double-layer electromagnetic shielding cabinet with inner ground isolation, characterized in that: The insulating support block (14) is made of insulating ceramic support material, and its outer surface is covered with thermally conductive insulating silica gel to assist in heat conduction; The plurality of insulating support blocks (14) are respectively located between the gaps on the sides of the outer shielding box (1) and the inner shielding box (2) except the front side.

5. A double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 4, characterized in that: The two waveguide windows (11) are respectively located on the back surface and the top surface of the outer shielding box body (1); the waveguide window (11) located on the back surface is higher than the insulating support block (14) in the back surface gap, and the waveguide window (11) located on the top surface is arranged closer to the back surface than the insulating support block (14) in the top surface gap.

6. The double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 5, characterized in that: The waveguide tube (5) is made of the same material as the outer shielding box (1) and is welded to the outer shielding box (1).

7. The double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 6, characterized in that: The bottom surface of the outer shielding box (1) is provided with four fixable rollers (13), and the top surface is provided with four hanging rings (12).

8. The double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 7, characterized in that: The insulating support block (14) has a thickness of 8 cm, and a length and width of 15 cm; The thickness of the thermally conductive insulating silica gel is 0.5 cm; The insulating support blocks (14) located in the gaps on the back, left and right sides are respectively located in the middle of the sides and are provided with two of them at an interval of 30 cm; Nine insulating support blocks (14) are provided in the bottom surface gap and are evenly distributed in the bottom surface gap; The insulating support block (14) is also provided between the front gaps of the outer shielding box (1) and the inner shielding box (2) to make the gaps smooth.

9. The double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 8, characterized in that: The lighting device (10) comprises an LED lamp and a switch thereof.

10. The double-layer electromagnetic shielding cabinet with inner ground isolation according to claim 9, characterized in that: The specifications of the power supply filter (7) are rated voltage 220AC, operating frequency 50 / 60Hz, maximum current 32A, and electromagnetic shielding effectiveness 100dB@(1MHz-10GHz).

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