A metal cavity filter

Abstract

This invention relates to the field of filter technology and discloses a metal cavity filter, comprising a cavity. A cover plate is detachably and sealed to the upper end of the cavity via multiple bolts. Two resonant pillars are symmetrically fixed to the bottom of the cavity along its center. Three metal tuning rods are slidably connected through the sidewall of the cover plate, with two of the metal tuning rods extending into the two resonant pillars respectively. An adjustment mechanism is provided at the upper end of the cover plate. The adjustment mechanism includes three fixed frames fixedly connected to the upper end of the cover plate, each corresponding to one of the three metal tuning rods. A first plate is slidably and sealed to the inner wall of each of the three fixed frames. This invention allows for the adjustment of the height of specific metal tuning rods, thereby adjusting the frequency of the filter. During this process, the adjustment of the metal tuning rods is performed in a sealed environment, preventing external dust from entering the cavity.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and in particular to a metal cavity filter. Background Technology

[0002] As a typical frequency selection device, a filter allows specific frequency components in a signal to pass through smoothly while significantly attenuating other frequency components. It is mainly used to filter out or reduce useless components such as noise and interference in the input signal, thereby achieving accurate extraction of useful signals.

[0003] In the patent application "A Variable Coupling Value Structure for a Filter Coupling Window" with application number "202210996649.8", the center frequency of the filter is determined by the resonant pillar and the tuning screw on the resonant pillar. Different coupling values ​​are obtained by using copper sheet metal supports of different heights and adjustable window coupling copper sheets of different lengths, widths, and folding heights between the two resonant cavities. The models of the copper sheet metal supports and adjustable window coupling copper sheets are selected according to the required passband width to meet the customer's needs for different passband widths. However, the following defects exist in actual use:

[0004] 1. The tuning screw and the cover plate are installed with a threaded connection. During the adjustment process of the tuning screw rotating relative to the cover plate, dust is easily attached to the threaded connection between the two, which makes it easy for dust to fall into the filter cavity and affect the tuning accuracy and performance of the filter.

[0005] 2. When adjusting the coupling value, the adjustable window coupling copper plate needs to be disassembled, replaced and reinstalled. The entire filter needs to be disassembled and reassembled during the operation, which will not only damage the sealed environment of the cavity and affect the electromagnetic performance of the filter, but also reduce the adjustment efficiency of the coupling value and increase the debugging and maintenance costs. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art by proposing a metal cavity filter.

[0007] To achieve the above objectives, this application adopts the following technical solution: a metal cavity filter, including a cavity, a cover plate detachably connected to the upper end of the cavity by multiple bolts, two resonant columns fixedly and symmetrically connected to the bottom of the cavity along the center, three metal tuning rods slidably connected through the side wall of the cover plate, two of the metal tuning rods extending into the two resonant columns respectively, and an adjustment mechanism provided at the upper end of the cover plate;

[0008] The adjustment mechanism includes three fixed frames fixedly connected to the upper end of the cover plate. Each of the three fixed frames corresponds to one of the three metal tuning rods. The inner walls of each of the three fixed frames are sealed and slidably connected to a first plate. The upper end of the first plate is fixedly connected to the upper end of its corresponding metal tuning rod via a U-shaped rod. The lower end of the first plate is elastically connected to the bottom of the fixed frame via multiple springs. The upper end of the cover plate is detachably and sealed with a dust cover via multiple bolts. The three fixed frames are all located inside the dust cover. A pump frame is fixedly connected to the upper end of the cover plate. The inner wall of the pump frame is sealed and slidably connected to a second plate. The inner walls of the three fixed frames are fixedly connected to the inner wall of the pump frame via fixed pipes. The side walls of the three fixed pipes are sealed and fixedly connected to the side walls of the dust cover.

[0009] Preferably, each of the three fixed pipes is equipped with a manual regulating valve on its inner wall to control the opening and closing of the fixed pipes, and the pump frame contains coolant.

[0010] Preferably, an L-shaped plate is fixedly connected to the side wall of the pump frame away from the fixed pipe, and a threaded rod is threadedly connected to the side wall of the L-shaped plate. The side wall of the threaded rod is rotatably connected to the side wall of the second plate. Nuts are threadedly connected to the side walls of the threaded rod on both sides of the L-shaped plate, and anti-loosening washers are sleeved on the side wall of the threaded rod between the L-shaped plate and the nuts.

[0011] Preferably, the lower end of the cavity has a groove, and a rigid tube is fixedly connected through the top of the groove. A hollow plate is rotatably connected through the upper end of the rigid tube. Hollow columns are fixedly connected to both ends of the hollow plate. Copper sheets are rotatably connected to the side walls of the two hollow columns. A first opening groove is opened in the top of the two hollow columns. A rotating shaft is rotatably connected to the inner wall of the two hollow columns. The side wall of the rotating shaft is fixedly connected to the lower end of its corresponding copper sheet through two connecting rods. The side walls of the two connecting rods penetrate the inner wall of the first opening groove.

[0012] Preferably, the hollow plate is provided with a driving mechanism, which includes two fixed plates fixedly connected to the inner wall of the hollow plate. The side walls of the two fixed plates are slidably connected with toothed plates. The inner walls of the two hollow columns are provided with second opening slots that communicate with the inside of the hollow plate. The two toothed plates pass through the two second opening slots respectively. The side walls of the two rotating shafts are fixedly connected with gears. The side walls of the two toothed plates mesh with the side walls of the two gears respectively.

[0013] Preferably, the inner wall of the groove has two sliding grooves, and the inner walls of the two sliding grooves are slidably connected to a sliding plate. A vertical rod is rotatably connected through the side wall of the sliding plate, and the side wall of the vertical rod penetrates the inner wall of the rigid tube. The upper end of the vertical rod is rotatably connected to the side wall of the two toothed plates through two rotating rods respectively.

[0014] Preferably, a handplate is fixedly connected to the side wall of the skateboard, the side wall of the handplate is in contact with the side wall of the cavity, and two first hexagonal screws are threaded through the side wall of the handplate. The side walls of the two first hexagonal screws abut against the side wall of the cavity, and the side wall of the skateboard and the side wall of the handplate are threaded together with a second hexagonal screw, the side wall of the second hexagonal screw abutting against the side wall of the vertical rod.

[0015] Preferably, an input connector is fixedly connected to one side wall of the cavity, and an output connector is fixedly connected to the other side wall of the cavity. The inner cores of both the input connector and the output connector extend into the cavity, and a mounting plate is fixedly connected to the side wall of the cavity.

[0016] The technical effects and advantages of this invention are as follows:

[0017] 1. An adjustment mechanism is provided to adjust the height of a specific metal tuning rod, thereby adjusting the frequency of the filter. During this process, the adjustment of the metal tuning rod is carried out in a sealed environment, preventing external dust from entering the cavity. This avoids the problem in existing technologies where the tuning screw is installed with a threaded connection to the cover plate, and dust can easily fall into the filter cavity during the adjustment process of the tuning screw relative to the cover plate, affecting the tuning accuracy and performance of the filter.

[0018] 2. A drive mechanism is set up so that two rotating shafts drive two copper plates to rotate along the shaft axis through two connecting rods, changing the relative overlap area between the two copper plates and the two resonant pillars. Combined with the detection of the coupling value change by an external capacitor sensor, the position is corrected in real time by an external control module based on feedback, so as to achieve precise matching of the coupling value. When it is not necessary to adjust the coupling value of the two copper plates, they can be disassembled, replaced and reinstalled, avoiding damage to the sealed environment of the cavity, which would affect the electromagnetic performance of the filter and reduce the adjustment efficiency of the coupling value, thus increasing the debugging and maintenance costs.

[0019] 3. Simultaneously, when the vertical rod rotates, the two rotating rods drive the two toothed plates to rotate, which in turn drive the hollow plate to rotate through the two fixed plates, causing the two copper plates to rotate along the axis of the rigid tube. This can again change the relative overlap area between the two copper plates and the two resonant pillars, thus accelerating the adjustment of the coupling value. Attached Figure Description

[0020] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0021] Figure 1 This is a schematic diagram of the structure of a metal cavity filter according to the present invention;

[0022] Figure 2 for Figure 1A schematic diagram of the vertical sectional structure;

[0023] Figure 3 for Figure 2 Enlarged structural diagram at point A;

[0024] Figure 4 for Figure 1 A schematic diagram of the rear structure after the mounting plate has been removed;

[0025] Figure 5 This is a top sectional view of the adjustment mechanism in this invention.

[0026] Figure 6 for Figure 5 Enlarged structural diagram at point B;

[0027] Figure 7 for Figure 2 Enlarged structural diagram at point C;

[0028] Figure 8 for Figure 7 Enlarged structural diagram at point D;

[0029] Figure 9 for Figure 1 A schematic diagram of the structure viewed from below;

[0030] Figure 10 for Figure 9 A schematic diagram of the transverse cross-sectional structure at the middle skateboard and handboard;

[0031] Figure 11 for Figure 10 A magnified schematic diagram of the structure at point E in the middle.

[0032] Legend: 1. Cavity; 2. Cover plate; 3. Input connector; 4. Output connector; 5. Resonant column; 6. Metal tuning rod; 7. Fixing frame; 8. First plate; 9. U-shaped rod; 10. Spring; 11. Dust cover; 12. Pump frame; 13. Second plate; 14. Fixing pipe; 15. Manual regulating valve; 16. L-shaped plate; 17. Threaded rod; 18. Anti-loosening washer; 19. Nut; 20. Groove; 21. Rigid tube; 22. Hollow plate; 23. Hollow column; 24. Copper sheet; 25. First opening groove; 26. Rotating shaft; 27. Connecting rod; 28. Second opening groove; 29. ​​Fixing plate; 30. Toothed plate; 31. Gear; 32. Slide groove; 33. Slide plate; 34. Vertical rod; 35. Rotating rod; 36. Hand plate; 37. First hexagonal screw; 38. Second hexagonal screw. Detailed Implementation

[0033] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0034] Reference Figures 1-11 As shown, the present invention provides a technical solution: a metal cavity filter, including a cavity 1, a cover plate 2 detachably connected to the upper end of the cavity 1 by multiple bolts, an input connector 3 fixedly connected to one side wall of the cavity 1, and an output connector 4 fixedly connected to the other side wall of the cavity 1. The inner cores of the input connector 3 and the output connector 4 both extend into the cavity 1. A mounting plate is fixedly connected to the side wall of the cavity 1. Two resonant pillars 5 are symmetrically fixedly connected to the bottom of the cavity 1 along the center. Three metal tuning rods 6 are slidably connected through the side wall of the cover plate 2, wherein two of the metal tuning rods 6 extend into the two resonant pillars 5 respectively (e.g., Figure 2 (As shown).

[0035] It should be noted that the resonant column 5 is a component used to adjust the frequency response of the filter. By adjusting its parameters, the filter can be made to allow signals within a specific frequency range to pass through, thereby achieving frequency selection. By changing its resonant frequency, the gain of the filter at a specific frequency can be adjusted, and the signal can be amplified or attenuated.

[0036] The upper end of the cover plate 2 is provided with an adjustment mechanism, which includes three fixed frames 7 fixedly connected to the upper end of the cover plate 2. The three fixed frames 7 correspond one-to-one with three metal tuning rods 6. The inner walls of the three fixed frames 7 are all sealed and slidably connected with a first plate 8. The upper end of the first plate 8 is fixedly connected to the upper end of its corresponding metal tuning rod 6 through a U-shaped rod 9. The lower end of the first plate 8 is elastically connected to the bottom of the fixed frame 7 through multiple springs 10. The upper end of the cover plate 2 is detachably connected to a dust cover 11 sealed by multiple bolts. The three fixed frames 7 are all located inside the dust cover 11. The upper end of the cover plate 2 is fixedly connected to a pump frame 12. The inner wall of the pump frame 12 is sealed and slidably connected with a second plate 13. The inner walls of the three fixed frames 7 are all fixedly connected to the inner wall of the pump frame 12 through fixed pipes 14. The side walls of the three fixed pipes 14 are all sealed and fixedly connected to the side walls of the dust cover 11.

[0037] Each of the three fixed pipes 14 has a manual regulating valve 15 installed on its inner wall (e.g., Figure 4 and Figure 5 As shown), it is used to control the opening and closing of the fixed pipe 14, and the pump frame 12 is filled with coolant.

[0038] When the height of the three metal tuning rods 6 needs to be adjusted, the manual adjustment valve 15 corresponding to the metal tuning rod 6 to be adjusted can be opened, so that the fixed tube 14 corresponding to the metal tuning rod 6 to be adjusted can be opened. Then, the second plate 13 slides on the inner wall of the pump frame 12, so that the coolant in the pump frame 12 can flow through the fixed tube 14 into the fixed frame 7 corresponding to the metal tuning rod 6 to be adjusted. This causes the first plate 8 in the fixed frame 7 to move up and down, and through the U-shaped rod 9, it drives the metal tuning rod 6 to move up and down, thereby adjusting the height of the metal tuning rod 6 and thus adjusting the frequency of the filter. During this process, the adjustment of the metal tuning rod 6 is carried out in a closed environment, which will not cause external dust to enter the cavity 1. This avoids the problem in the prior art where the tuning screw is installed by threaded engagement with the cover plate 2. During the adjustment process of the tuning screw relative to the cover plate 2, dust can easily fall into the filter cavity, affecting the tuning accuracy and performance of the filter.

[0039] At the same time, coolant is provided to absorb the heat in the cavity 1 that is passed through the first plate 8, U-shaped rod 9 and metal tuning rod 6, so as to avoid the frequency instability of the filter caused by the temperature rise in the cavity 1.

[0040] An L-shaped plate 16 is fixedly connected to the side wall of the pump frame 12 away from the fixed pipe 14. A threaded rod 17 is threadedly connected through the side wall of the L-shaped plate 16. The side wall of the threaded rod 17 is rotatably connected to the side wall of the second plate 13. Nuts 19 are threadedly connected to the side walls of the threaded rod 17 on both sides of the L-shaped plate 16. Anti-loosening gaskets 18 are fitted on the side wall of the threaded rod 17 between the L-shaped plate 16 and the nuts 19.

[0041] The threaded rod 17 can rotate in either the forward or reverse direction to drive the second plate 13 to slide on the inner wall of the pump frame 12. After the frequency of the filter is adjusted, the two nuts 19 can be rotated to fit tightly against the side walls of the L-shaped plate 16, fixing the rotation position of the threaded rod 17 and ensuring the stability of the filter frequency.

[0042] A groove 20 is provided at the lower end of cavity 1. A rigid tube 21 is fixedly connected through the top of the groove 20. A hollow plate 22 is rotatably connected through the upper end of the rigid tube 21. Hollow columns 23 are fixedly connected to both ends of the hollow plate 22. Copper sheets 24 are rotatably connected to the side walls of the two hollow columns 23. A first opening groove 25 is provided at the top of the two hollow columns 23. A rotating shaft 26 is rotatably connected to the inner wall of the two hollow columns 23. The side walls of the rotating shaft 26 are fixedly connected to the lower ends of the corresponding copper sheets 24 via two connecting rods 27 (e.g., Figure 8 As shown), the sidewalls of the two connecting rods 27 penetrate the inner wall of the first opening slot 25.

[0043] It should be noted that the metal tuning lever 6 in the middle is directly opposite the two copper plates 24.

[0044] The hollow plate 22 is equipped with a driving mechanism, which includes two fixed plates 29 fixedly connected to the inner wall of the hollow plate 22. The side walls of the two fixed plates 29 are slidably connected with toothed plates 30. The inner walls of the two hollow columns 23 are provided with second opening slots 28 that communicate with the hollow plate 22. The two toothed plates 30 pass through the two second opening slots 28 respectively. The side walls of the two rotating shafts 26 are fixedly connected with gears 31. The side walls of the two toothed plates 30 mesh with the side walls of the two gears 31 respectively.

[0045] The inner wall of the groove 20 has two sliding grooves 32, and the inner walls of the two sliding grooves 32 are slidably connected to a slide plate 33. The side wall of the slide plate 33 is rotatably connected to a vertical rod 34, and the side wall of the vertical rod 34 passes through the inner wall of the rigid tube 21. The upper end of the vertical rod 34 is rotatably connected to the side wall of the two toothed plates 30 respectively through two rotating rods 35.

[0046] The sliding plate 33 moves up and down, causing the vertical rod 34 to move up and down. The vertical rod 34 drives the two toothed plates 30 to slide horizontally via two rotating rods 35. The two toothed plates 30 drive the two rotating shafts 26 to rotate via two gears 31. This causes the two rotating shafts 26 to drive the two copper plates 24 to rotate along the axis of the shafts 26 via two connecting rods 27, changing the relative overlap area between the two copper plates 24 and the two resonant pillars 5. Combined with the detection of changes in coupling value by an external capacitor sensor, and the real-time correction of position by an external control module based on feedback, the coupling value is accurately matched. This avoids the need to disassemble, replace, and reinstall the two copper plates 24 when the coupling value does not need to be adjusted, thus avoiding damage to the sealed environment of the cavity, which would affect the electromagnetic performance of the filter and reduce the adjustment efficiency of the coupling value, increasing debugging and maintenance costs.

[0047] Furthermore, the two hollow columns 23 are sealed and rotatably connected to the two copper plates 24. At the same time, when the two copper plates 24 rotate, the two connecting rods 27 will prevent the top of the two first opening slots 25 from opening, thus preventing external dust from entering the cavity 1. Meanwhile, the rigid tube 21 is sealed and rotatably connected to the hollow plate 22, which also prevents external dust from entering the cavity 1.

[0048] When the vertical rod 34 rotates, the two rotating rods 35 drive the two toothed plates 30 to rotate, which in turn drive the hollow plate 22 to rotate through the two fixed plates 29, causing the two copper plates 24 to rotate along the axis of the rigid tube 21. This can change the relative overlap area between the two copper plates 24 and the two resonant pillars 5, thus accelerating the adjustment of the coupling value.

[0049] A handplate 36 is fixedly connected to the side wall of the slide plate 33. The side wall of the handplate 36 fits against the side wall of the cavity 1. Two first hexagonal screws 37 are threadedly connected to the side wall of the handplate 36. Figure 11As shown), the sidewalls of the two first hexagonal screws 37 abut against the sidewall of the cavity 1 respectively, and the sidewalls of the slide plate 33 and the hand plate 36 are threadedly connected to the second hexagonal screw 38, and the sidewall of the second hexagonal screw 38 abuts against the sidewall of the vertical rod 34.

[0050] After adjusting the height of the slide plate 33, the two first hexagonal screws 37 are rotated to make their sidewalls abut against the sidewalls of the cavity 1, thereby adjusting the height of the slide plate 33 and fixing the rotation angle of the two copper plates 24 along the axis of the rotating shaft 26. After adjusting the rotation angle of the vertical rod 34, the second hexagonal screw 38 is rotated to make its sidewalls abut against the sidewalls of the vertical rod 34, thereby adjusting the height of the vertical rod 34 and fixing the rotation angle of the two copper plates 24 along the axis of the rigid tube 21.

[0051] When this metal cavity filter is in use, the external signal to be processed is transmitted into the cavity 1 through the input connector 3, and after filtering, it is exported through the output connector 4. The two resonant pillars 5, which are symmetrically arranged along the center at the bottom of the cavity 1, are the core components for frequency response adjustment. They can be adjusted through their own parameters so that the filter only allows signals in a specific frequency range to pass through.

[0052] When it is necessary to adjust the frequency of the two resonant columns 5, that is, to adjust the height of the two metal tuning rods 6 that are far apart from each other, first open the manual adjustment valves 15 on the two corresponding fixed tubes 14 to connect the two fixed tubes 14. Then, rotate the two nuts 19 to separate the two side walls of the L-shaped plate 16 respectively, and manually drive the threaded rod 17 to rotate in the forward or reverse direction, causing the second plate 13 to slide on the inner wall of the pump frame 12. The pressure difference is used to push the coolant to flow through the fixed tubes 14 into the corresponding fixed frame 7. The coolant pushes the first plate 8 to move up and down against the elastic force of the spring 10. The first plate 8 drives the metal tuning rod 6 to slide up and down synchronously through the U-shaped rod 9, thereby changing the depth of the metal tuning rod 6 into the resonant column 5, realizing the precise adjustment of the filter frequency. After the adjustment is completed, close the manual adjustment valve 15 to block the flow of coolant. The elastic force of the spring 10 can help fix the position of the first plate 8, ensuring the stability of the position of the metal tuning rod 6, and thus ensuring the stability after frequency adjustment.

[0053] During the flow of the coolant, the heat generated in the cavity 1 can be absorbed through the first plate 8, U-shaped rod 9 and metal tuning rod 6, which prevents the temperature inside the cavity 1 from rising and causing the parameters of the resonant column 5 to deviate and the filter frequency to become unstable. This achieves the dual functions of heat dissipation and regulation. At the same time, the dust cover 11 encloses the three fixed frames 7, the adjustment mechanism and the pump frame 12 and is sealed to the cover plate 2, which increases the dustproof effect and prevents dust from entering the cavity 1, thus ensuring the adjustment accuracy and the service life of the filter.

[0054] After adjusting the frequency of the filter, the two nuts 19 can be rotated to fit tightly against the side walls of the L-shaped plate 16, fixing the rotation position of the threaded rod 17 and ensuring the stability of the filter's frequency.

[0055] When it is necessary to adjust the coupling value inside cavity 1, firstly rotate the two first hexagonal screws 37 to separate them from the side wall of cavity 1, and then slide the slide plate 33 up and down. The slide plate 33 slides up and down, which drives the vertical rod 34 to slide up and down. The vertical rod 34 drives the two toothed plates 30 to slide horizontally through the two rotating rods 35. The two toothed plates 30 drive the two rotating shafts 26 to rotate through the two gears 31. This causes the two rotating shafts 26 to drive the two copper plates 24 to rotate along the axis of the rotating shaft 26 through the two connecting rods 27, thereby changing the relative overlap area between the two copper plates 24 and the two resonant pillars 5. Combined with the detection of the coupling value change by the external capacitor sensor, the position is corrected in real time by the external control module based on the feedback, so as to achieve precise matching of the coupling value.

[0056] At the same time, the second hexagonal screw 38 can be rotated to separate from the vertical rod 34. Then, the vertical rod 34 can be manually rotated. At this time, the two rotating rods 35 drive the two toothed plates 30 to rotate, and then the two fixed plates 29 drive the hollow plate 22 to rotate, which drives the two copper plates 24 to rotate along the axis of the rigid tube 21. This can change the relative overlap area between the two copper plates 24 and the two resonant pillars 5 again, and speed up the adjustment of the coupling value.

[0057] After adjusting the height of the slide plate 33, rotate the two first hexagonal screws 37 so that their sidewalls are tightly against the sidewalls of the cavity 1 to adjust the height of the slide plate 33 and fix the angle of rotation of the two copper plates 24 along the axis of the rotating shaft 26. After adjusting the rotation angle of the vertical rod 34, rotate the second hexagonal screw 38 so that its sidewalls are tightly against the sidewalls of the vertical rod 34 to adjust the height of the vertical rod 34 and fix the angle of rotation of the two copper plates 24 along the axis of the rigid tube 21.

[0058] Then, adjust the height of the metal tuning rod 6 corresponding to the two copper plates 24 according to the above steps, and fine-tune its coupling value to determine it.

[0059] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A metal cavity filter, characterized in that, Includes a cavity (1), the upper end of which is detachably connected to a cover plate (2) by multiple bolts, and two resonant columns (5) are fixedly and symmetrically connected to the bottom of the cavity (1) along the center. Three metal tuning rods (6) are slidably connected through the side wall of the cover plate (2), two of which extend into the two resonant columns (5) respectively. An adjustment mechanism is provided at the upper end of the cover plate (2). The adjustment mechanism includes three fixed frames (7) fixedly connected to the upper end of the cover plate (2). The three fixed frames (7) correspond one-to-one with three metal tuning rods (6). The inner walls of the three fixed frames (7) are all sealed and slidably connected with a first plate (8). The upper end of the first plate (8) is fixedly connected to the upper end of its corresponding metal tuning rod (6) through a U-shaped rod (9). The lower end of the first plate (8) is elastically connected to the bottom of the fixed frame (7) through multiple springs (10). The cover plate (2) The upper end of the cover plate (2) is detachably connected to a dust cover (11) by multiple bolts. All three fixed frames (7) are located inside the dust cover (11). The upper end of the cover plate (2) is fixedly connected to a pump liquid frame (12). The inner wall of the pump liquid frame (12) is slidably connected to a second plate (13). The inner walls of the three fixed frames (7) are fixedly connected to the inner wall of the pump liquid frame (12) through fixed pipes (14). The side walls of the three fixed pipes (14) are fixedly connected to the side wall of the dust cover (11).

2. A metal cavity filter according to claim 1, characterized in that: The inner walls of the three fixed tubes (14) are each equipped with a manual regulating valve (15) to control the opening and closing of the fixed tubes (14), and the pump frame (12) contains coolant.

3. A metal cavity filter according to claim 1, characterized in that: The pump frame (12) is fixedly connected to an L-shaped plate (16) on the side wall away from the fixed pipe (14). A threaded rod (17) is threaded through the side wall of the L-shaped plate (16). The side wall of the threaded rod (17) is rotatably connected to the side wall of the second plate (13). Nuts (19) are threadedly connected to the side walls of the threaded rod (17) on both sides of the L-shaped plate (16). Anti-loosening gaskets (18) are fitted on the side wall of the threaded rod (17) between the L-shaped plate (16) and the nuts (19).

4. A metal cavity filter according to claim 1, characterized in that: The cavity (1) has a groove (20) at its lower end. A rigid tube (21) is fixedly connected through the top of the groove (20). A hollow plate (22) is rotatably connected through the upper end of the rigid tube (21). Hollow columns (23) are fixedly connected to both ends of the hollow plate (22). Copper sheets (24) are rotatably connected to the side walls of the two hollow columns (23). A first opening groove (25) is opened at the top of the two hollow columns (23). A rotating shaft (26) is rotatably connected to the inner wall of the two hollow columns (23). The side wall of the rotating shaft (26) is fixedly connected to the lower end of the corresponding copper sheet (24) through two connecting rods (27). The side walls of the two connecting rods (27) penetrate the inner wall of the first opening groove (25).

5. A metal cavity filter according to claim 4, characterized in that: The hollow plate (22) is provided with a driving mechanism, which includes two fixed plates (29) fixedly connected to the inner wall of the hollow plate (22). The side walls of the two fixed plates (29) are slidably connected with toothed plates (30). The inner walls of the two hollow columns (23) are provided with second opening slots (28) that communicate with the hollow plate (22). The two toothed plates (30) are respectively connected to the two second opening slots (28). The side walls of the two rotating shafts (26) are fixedly connected with gears (31). The side walls of the two toothed plates (30) mesh with the side walls of the two gears (31).

6. A metal cavity filter according to claim 5, characterized in that: The inner wall of the groove (20) has two sliding grooves (32), and the inner walls of the two sliding grooves (32) are slidably connected to a sliding plate (33). The side wall of the sliding plate (33) is rotatably connected to a vertical rod (34), and the side wall of the vertical rod (34) penetrates the inner wall of the rigid tube (21). The upper end of the vertical rod (34) is rotatably connected to the side wall of the two toothed plates (30) respectively through two rotating rods (35).

7. A metal cavity filter according to claim 6, characterized in that: The side wall of the slide plate (33) is fixedly connected to a hand plate (36). The side wall of the hand plate (36) is in contact with the side wall of the cavity (1). The side wall of the hand plate (36) is threadedly connected to two first hexagonal screws (37). The side walls of the two first hexagonal screws (37) abut against the side wall of the cavity (1) respectively. The side wall of the slide plate (33) and the side wall of the hand plate (36) are threadedly connected to a second hexagonal screw (38). The side wall of the second hexagonal screw (38) abuts against the side wall of the vertical rod (34).

8. A metal cavity filter according to claim 1, characterized in that: An input connector (3) is fixedly connected to one side wall of the cavity (1), and an output connector (4) is fixedly connected to the other side wall of the cavity (1). The inner cores of the input connector (3) and the output connector (4) extend into the cavity (1). An installation plate is fixedly connected to the side wall of the cavity (1).

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