A sealing structure of a secondary end of a current transformer

Abstract

This invention discloses a sealing structure for the secondary terminal of a current transformer, including a junction box, a transformer body, and a cover. The junction box is fixedly connected to the outer wall of the transformer body, and triangular connecting plates are fixedly connected to the four corners of the inner wall of the junction box. Each of the four triangular connecting plates has screw holes, and the cover also has screw holes at its four corners. The junction box and cover are connected by fixing screws through the corresponding screw holes. This invention provides two seals for the cable, effectively improving the sealing effect of the current transformer's secondary terminal. Even if one seal fails, it still provides a sealing and waterproof function. Furthermore, in cold outdoor environments with low temperatures, the annular gas liquefies at low temperatures, allowing for further expansion and re-inflation of the gasket to fill the gaps caused by the cold expansion and contraction of the cable sheath, ensuring a good sealing effect.

Description

Technical Field

[0001] This invention relates to the field of protective sealing technology, and in particular to a sealing structure for the secondary end of a current transformer. Background Technology

[0002] A current transformer is an instrument that converts a large primary current into a small secondary current based on the principle of electromagnetic induction. A current transformer consists of a primary coil, a secondary coil, and an iron core that forms the common magnetic circuit of these coils. The two important functions of a current transformer are to bill or measure the current of equipment in operation and to protect the circuit.

[0003] For current transformers currently used outdoors, since the current transformers are installed on the outside and the secondary wiring cable lacks a sealing mechanism or the sealing is poor, water seepage is likely to occur at the secondary wiring under the constant exposure to wind and rain, which can lead to leakage or poor contact in the wiring cable. Therefore, a sealing structure for the secondary end of the current transformer is proposed. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art by proposing a sealing structure for the secondary end of a current transformer.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A sealing structure for the secondary side of a current transformer includes a junction box, a transformer body, and a cover. The junction box is fixedly connected to the outer wall of the transformer body. Triangular connecting plates are fixedly connected to the four corners of the inner wall of the junction box. Each of the four triangular connecting plates has screw holes. Screw holes are also provided at the four corners of the cover. Fixing screws are provided in the corresponding screw holes of the junction box and the cover. Four wiring terminals are provided on the inner wall of the junction box near the transformer body. Two wire-passing holes are provided on both sides of the junction box. A fixing mechanism is provided at each wire-passing hole of the junction box.

[0007] In the sealing structure of the secondary terminal of the current transformer described above, the fixing mechanism includes a regular hexagonal prism-shaped connecting block, a connecting ring is coaxially fixedly connected to the outer wall of the junction box at each wire hole, the outer ring surface of the connecting ring is provided with an external thread, a cylindrical wire groove is provided through the connecting block, an internal thread is provided on the inner groove wall at one end of the wire groove, and the connecting block and the connecting ring are connected by threads.

[0008] In the sealing structure of the secondary end of the current transformer described above, a first annular groove is coaxially formed on the inner groove wall of the end of the connecting ring away from the internal thread. An annular slide plate is slidably connected in the first annular groove. An elastic sealing ring is glued to the side of the annular slide plate away from the internal thread. The end of the connecting ring away from the junction box is fixedly connected by two symmetrically distributed push rods.

[0009] In the sealing structure of the secondary terminal of the current transformer described above, a second annular groove is provided on the wall of each wire hole, and an annular airbag is fixedly connected inside the groove wall of the second annular groove. Cavities are provided at the four corners of the junction box, and sealing blocks are slidably connected inside the cavities. A vent pipe is sealed to the bottom of the cavity, and the end of the vent pipe away from the cavity is sealed to the annular airbag. A threaded groove is provided on the side of the sealing block away from the vent pipe. A main shaft is rotatably connected to one side wall of the cavity via a bearing. A threaded shaft is coaxially fixed to one end of the main shaft, and the threaded shaft is threadedly connected to the threaded groove on the sealing block. A rotating shaft is rotatably connected through the top wall of the cavity. A first bevel gear is coaxially fixed to the end of the main shaft away from the threaded shaft, and a second bevel gear is coaxially fixed to the end of the rotating shaft located inside the cavity. The first bevel gear and the second bevel gear mesh with each other. A control button is coaxially fixed to the end of the rotating shaft located outside the junction box.

[0010] In the sealing structure of the secondary end of the current transformer described above, a control box is fixedly connected to the top cavity wall of the cavity and to the side of the sealing block away from the main shaft. A piston block is slidably connected inside the control box. A connecting rod is fixedly connected to the side of the piston block away from the sealing block. The end of the connecting rod away from the piston block extends to the outside of the control box. A sealing plate is fixedly connected to the end of the connecting rod outside the control box. The sealing plate is slidably connected to the cavity wall of the cavity.

[0011] In the sealing structure of the secondary end of the current transformer described above, the control box is filled with low-temperature liquefied gas on the side of the piston block away from the connecting rod, and each cavity has a vent hole at both ends to communicate with the outside.

[0012] In the sealing structure of the secondary terminal of the current transformer described above, a U-shaped sealing groove is provided on the side of the junction box near the cover, and a U-shaped sealing strip is provided in the sealing groove. The junction box, cover, connecting ring and connecting block are all made of stainless steel.

[0013] In the sealing structure of the secondary terminal of the current transformer described above, the inner wall of the junction box and at each through hole are rotatably connected to a baffle by a pin, and a torsion spring is provided at the rotatable connection of each baffle.

[0014] The present invention has the following advantages:

[0015] 1. This invention improves the sealing effect of the secondary terminal of the current transformer by setting two seals at the wiring hole of the junction box for the cable connecting the wires, and still provides a sealing and water-proof function when one of the seals fails.

[0016] 2. This invention uses an elastic sealing ring to compress and expand towards the center, thus wrapping the cable sheath located in the cable groove. This achieves a sealing effect, preventing rainwater from damaging the cable sheath and flowing into the cable hole. It also serves to fix the cable and prevent the cable joint from falling off.

[0017] 3. In cold seasons when the outdoor ambient temperature is low, this invention utilizes the characteristic of methylamine gas liquefying at low temperatures to squeeze a portion of the air in the cavity back into the annular airbag, causing the annular airbag to inflate further and fill the gap caused by the cold expansion and contraction of the cable sheath due to the temperature drop, thus ensuring a good sealing effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the sealing structure of the secondary end of a current transformer proposed in this invention.

[0019] Figure 2 This is a cross-sectional view of the junction box portion in the sealing structure of the secondary terminal of a current transformer proposed in this invention.

[0020] Figure 3 This is a cross-sectional view of the connecting block portion in the sealing structure of the secondary end of a current transformer proposed in this invention.

[0021] Figure 4 This is an enlarged schematic diagram of point A of the sealing structure of the secondary terminal of a current transformer proposed in this invention;

[0022] Figure 5 This is an enlarged schematic diagram of point B of the sealing structure of the secondary end of a current transformer proposed in this invention.

[0023] In the diagram: 1 Junction box, 2 Current transformer body, 3 Box cover, 4 Triangular connecting plate, 5 Screw hole, 6 Fixing screw, 7 Wire hole, 8 Terminal block, 9 Connecting ring, 10 Connecting block, 11 Through groove, 12 Internal thread, 13 External thread, 14 First annular groove, 15 Annular slide plate, 16 Elastic sealing ring, 17 Push rod, 18 Sealing groove, 19 Baffle, 20 Second annular groove, 21 Annular airbag, 22 Cavity, 23 Air guide tube, 24 Sealing block, 25 Main shaft, 26 Thread groove, 27 Rotating shaft, 28 First bevel gear, 29 Second bevel gear, 30 Control button, 31 Sealing plate, 32 Control box, 33 Piston block, 34 Connecting rod. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0025] Reference Figure 1-5 A sealing structure for the secondary end of a current transformer includes a junction box 1, a transformer body 2, and a cover 3. The junction box 1 is fixedly connected to the outer wall of the transformer body 2. Triangular connecting plates 4 are fixedly connected to the four corners of the inner wall of the junction box 1. Each of the four triangular connecting plates 4 has screw holes 5. Each of the four corners of the cover 3 also has screw holes 5. The junction box 1 and the cover 3 are connected by fixing screws 6 through the corresponding screw holes 5. Four terminals 8 are provided on the inner wall of the junction box 1 near the transformer body 2. Two wire holes 7 are provided on both sides of the junction box 1. A fixing mechanism is provided at each wire hole 7 of the junction box 1.

[0026] The fixing mechanism includes a hexagonal prism-shaped connecting block 10. A connecting ring 9 is coaxially fixed to the outer wall of the junction box 1 at each wire hole 7. The outer ring surface of the connecting ring 9 is provided with an external thread 13. A cylindrical wire groove 11 is opened through the connecting block 10. An internal thread 12 is opened on the inner wall of one end of the wire groove 11. The connecting block 10 and the connecting ring 9 are connected by threads. A first annular groove 14 is coaxially opened on the inner wall of the connecting ring 9 away from the internal thread 12. An annular slide plate 15 is slidably connected in the first annular groove 14. An elastic sealing ring 16 is glued to the side of the annular slide plate 15 away from the internal thread 12. The end of the connecting ring 9 away from the junction box 1 is fixedly connected by two symmetrically distributed push rods 17. The inner diameter of the wire hole 7, the connecting ring 9 and the diameter of the wire groove 11 of the connecting block 10 are all the same.

[0027] Each wire hole 7 has a second annular groove 20 on its wall. An annular airbag 21 is fixedly connected inside the groove wall of the second annular groove 20. Cavities 22 are provided at the four corners of the junction box 1. Sealing blocks 24 are slidably connected inside the cavities 22. A vent pipe 23 is sealed to the bottom of the cavity 22. The end of the vent pipe 23 away from the cavity 22 is sealed to the annular airbag 21. A threaded groove 26 is provided on the side of the sealing block 24 away from the vent pipe 23. A main bearing is rotatably connected to one side of the cavity wall of the cavity 22. Shaft 25, one end of the main shaft 25 is coaxially fixedly connected to a threaded shaft, the threaded shaft is threadedly connected to the threaded groove 26 on the sealing block 24, the top cavity wall of the cavity 22 is rotatably connected to a rotating shaft 27, the end of the main shaft 25 away from the threaded shaft is coaxially fixedly connected to a first bevel gear 28, the end of the rotating shaft 27 located in the cavity 22 is coaxially fixedly connected to a second bevel gear 29, the first bevel gear 28 and the second bevel gear 29 mesh with each other, the end of the rotating shaft 27 located outside the junction box 1 is coaxially fixedly connected to a control button 30.

[0028] A control box 32 is fixedly connected to the top wall of cavity 22 on the side of sealing block 24 away from main shaft 25. A piston block 33 is slidably connected inside control box 32. A connecting rod 34 is fixedly connected to the side of piston block 33 away from sealing block 24. The end of connecting rod 34 away from piston block 33 extends to the outside of control box 32. A sealing plate 31 is fixedly connected to the end of connecting rod 34 outside control box 32. The sealing plate 31 is slidably connected to the cavity wall of cavity 22. Low-temperature liquefied gas is filled inside control box 32 on the side of piston block 33 away from connecting rod 34. The low-temperature liquefied gas is methylamine gas with a boiling point of -6℃. Vent holes are opened at both ends of each cavity 22 to communicate with the outside.

[0029] A U-shaped sealing groove 18 is provided on the side of the junction box 1 near the cover 3. A U-shaped sealing strip is provided in the sealing groove 18. The junction box 1, cover 3, connecting ring 9 and connecting block 10 are all made of stainless steel. The inner wall of the junction box 1 is connected to a baffle 19 by a pin at each wire hole 7. A torsion spring is provided at the rotating connection of each baffle 19. When the wire hole 7 is not used for cable, the baffle 19 is in contact with the inner wall of the junction box 1 under the elastic force of the torsion spring to seal the wire hole 7 and prevent dust and insects from entering the junction box 1.

[0030] When using the cable connector in this invention, first unscrew the fixing screw 6 to remove the box cover 3 from the junction box 1. Then, pass one end of the cable connector through the through groove 11, connecting ring 9, and through hole 7 on the connecting block 10 in sequence. Then, connect and fix the cable connector inserted into the junction box 1 to the terminal 8. Afterward, rotate the connecting block 10 forward to tighten the screws between the connecting block 10 and the connecting ring 9. During the rotation of the connecting block 10, the push rod 17 on the connecting ring 9 will abut against the annular sliding plate 15 and push the annular sliding plate 15 to squeeze the elastic sealing ring 16. Due to the three-sided restriction of the first annular groove 14 and the annular sliding plate 15, the elastic sealing ring 16 expands and deforms towards the center after being squeezed by the annular sliding plate 15, and will be located in the through groove 11. The cable sheath inside serves two purposes: firstly, it provides a first layer of sealing, preventing rainwater from damaging the cable sheath and flowing into the cable hole 7; secondly, it secures the cable and prevents the cable joint from detaching. Then, rotating the control knob 30 drives the rotating shaft 27 to rotate, which in turn drives the main shaft 25 to rotate via the meshing of the second bevel gear 29 and the first bevel gear 28. The threaded control allows the sealing block 24 inside the cavity 22 to slide, pushing air from the cavity 22 into the annular airbag 21 through the air duct 23. The annular airbag 21 expands after inflation, wrapping the cable inside the cable hole 7 to form a second layer of sealing. By setting two layers of sealing, the sealing effect of the secondary end of the current transformer is improved, and it still provides a sealing and water-proof function even if one of the seals fails.

[0031] When the outdoor ambient temperature is low during the cold season, the methylamine gas in the control box 32 will liquefy into liquid methylamine after the temperature drops to the boiling point. During the liquefaction process, the volume decreases. Under the action of air pressure, the piston block 33 will slide towards the liquid methylamine side. The connecting rod 34 pulls the sealing plate 31 closer to the sealing block 24, and a part of the air in the cavity 22 is squeezed into the annular airbag 21 again through the air guide pipe 23, so that the annular airbag 21 expands further, filling the gap caused by the cold expansion and contraction of the cable sheath due to the temperature drop, ensuring a good sealing effect. When the temperature rises, the methylamine gas will vaporize, pushing the sealing plate 31 back to its original position and retracting the annular airbag 21.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A sealing structure for the secondary terminal of a current transformer, comprising a junction box (1), a transformer body (2), and a cover (3), characterized in that, A junction box (1) is fixedly connected to the outer wall of the transformer body (2). Triangular connecting plates (4) are fixedly connected to the four corners of the inner wall of the junction box (1). Each of the four triangular connecting plates (4) has a screw hole (5). Each of the four corners of the cover (3) has a screw hole (5). The junction box (1) and the cover (3) are connected by fixing screws (6). Four wiring terminals (8) are provided on the inner wall of the junction box (1) near the transformer body (2). Two wire holes (7) are provided on both sides of the junction box (1). A fixing mechanism is provided at each wire hole (7) of the junction box (1). The fixing mechanism includes a regular hexagonal prism-shaped connecting block (10), and a connecting ring (9) is coaxially fixedly connected to the outer wall of the junction box (1) at each wire hole (7). The outer ring surface of the connecting ring (9) is provided with an external thread (13). A cylindrical wire groove (11) is opened through the connecting block (10), and an internal thread (12) is opened on the inner groove wall at one end of the wire groove (11). The connecting block (10) and the connecting ring (9) are connected by threads. The connecting ring (9) has a first annular groove (14) coaxially formed on the inner groove wall at the end away from the internal thread (12). An annular slide plate (15) is slidably connected in the first annular groove (14). An elastic sealing ring (16) is glued to the side of the annular slide plate (15) away from the internal thread (12). Two symmetrically distributed push rods (17) are fixedly connected to the end of the connecting ring (9) away from the junction box (1). A cavity (22) is provided at each of the four corners of the junction box (1). A control box (32) is fixedly connected to the top wall of the cavity (22) on the side of the sealing block (24) away from the main shaft (25). A piston block (33) is slidably connected inside the control box (32). A connecting rod (34) is fixedly connected to the side of the piston block (33) away from the sealing block (24). One end of the connecting rod (34) away from the piston block (33) extends to the outside of the control box (32). A sealing plate (31) is fixedly connected to the end of the connecting rod (34) outside the control box (32). The sealing plate (31) is slidably connected to the cavity wall of the cavity (22). The control box (32) is filled with low-temperature liquefied gas on the side of the piston block (33) away from the connecting rod (34), and each cavity (22) has a vent at both ends to communicate with the outside.

2. The sealing structure for the secondary end of a current transformer according to claim 1, characterized in that, Each of the threading holes (7) has a second annular groove (20) on its wall. An annular airbag (21) is fixedly connected to the wall of the second annular groove (20). A sealing block (24) is slidably connected to the cavity (22). An air guide tube (23) is sealed to the bottom of the cavity (22). The end of the air guide tube (23) away from the cavity (22) is sealed to the annular airbag (21). A threaded groove (26) is provided on the side of the sealing block (24) away from the air guide tube (23). A main shaft (25) is rotatably connected to one side wall of the cavity (22) via a bearing. One end of the main shaft (25) is coaxially fixedly connected to a threaded shaft, and the threaded shaft is threadedly connected to the threaded groove (26) on the sealing block (24). The top cavity wall of the cavity (22) is rotatably connected to a rotating shaft (27). The end of the main shaft (25) away from the threaded shaft is coaxially fixedly connected to a first bevel gear (28). The rotating shaft (27) is located inside the cavity (22) and is coaxially fixedly connected to a second bevel gear (29). The first bevel gear (28) and the second bevel gear (29) mesh with each other. The rotating shaft (27) is located outside the junction box (1) and is coaxially fixedly connected to a control button (30).

3. The sealing structure of the secondary end of a current transformer according to claim 1, characterized in that, The junction box (1) has a U-shaped sealing groove (18) on the side near the cover (3), and a U-shaped sealing strip is provided in the sealing groove (18). The junction box (1), cover (3), connecting ring (9) and connecting block (10) are all made of stainless steel.

4. The sealing structure of the secondary end of a current transformer according to claim 1, characterized in that, The inner wall of the junction box (1) and at each wire hole (7) are rotatably connected to a baffle (19) by a pin, and a torsion spring is provided at the rotatable connection of each baffle (19).

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