Three-way valve applied to online verification of SF6 density relay

Abstract

The invention discloses a three-way valve applied to online verification of an SF6 density relay. The three-way valve comprises a three-way valve body, a port A, a port B, a port C, a valve rod, an operating rod, a cleaning and filtering assembly and a back flushing assembly. The three-way valve has the beneficial effects that on one hand, the three-way valve body can be prevented from being blocked, impurities can be prevented from being possibly accumulated in key parts such as a valve element and a valve seat in an internal structure of the three-way valve, a gas passage is narrowed or even blocked, and normal gas circulation is affected; the three-way valve is simple in structure and convenient to use, can smoothly switch gas circuit connection states, ensures normal operation of verification work, can timely clean cleaned impurities through arrangement of a plug, does not need to dismount the whole three-way valve for cleaning or replacement, is simple to operate, reduces operation and maintenance cost and time, avoids secondary damage to equipment, and improves work efficiency. And the reliability and the stability of the electrical equipment are further improved.

Description

Technical Field

[0001] The invention relates to a three-way valve, in particular to a three-way valve used for online calibration of an SF6 density relay, belonging to the technical field of three-way valves. Background Art

[0002] In the power system, SF6 gas-insulated electrical equipment is widely used due to its excellent insulation and arc extinguishing performance. As a key component for monitoring the SF6 gas density in the equipment, the accuracy of the SF6 density relay is directly related to the safe and stable operation of the electrical equipment. The traditional verification method requires cumbersome steps such as equipment power outage and gas recovery, which not only increases the operation and maintenance cost and power outage time, but also may cause safety hazards such as gas leakage due to improper operation. Therefore, the online verification method is often used. In this method, the three-way valve is the core component to achieve this function; In the prior art, a three-way valve and a three-way valve assembly disclosed in announcement number CN220416325U, through the cooperation between the U-shaped rod, the first straight wheel, the hand wheel and the second gear, during which the first straight wheel will rotate so as to be accurately stuck in the tooth gap, and then the hand wheel will be turned to drive the first straight wheel to rotate, and the first straight wheel will drive the second gear to rotate slowly, and the second gear will drive the ball valve to rotate through the rotating rod, so as to close the valve body of the three-way valve, thereby avoiding the failure to close the valve body of the three-way valve in time when the drive control component is damaged, and realizing the control of the internal fluid; However, when using the existing technology to monitor the SF6 gas density in the monitoring equipment, since SF6 gas may contain trace amounts of moisture and impurities during use, these substances are easy to accumulate inside the three-way valve, especially at the sealing part of the valve core and the valve seat and at the corners of the gas channel. The accumulation of impurities will cause the valve core to be blocked, making it impossible to smoothly switch the gas connection state, affecting the normal progress of the calibration work; on the other hand, it will destroy the sealing performance between the valve core and the valve seat, causing SF6 gas leakage, reducing the insulation performance of the equipment, and may even cause safety accidents. Moreover, the existing three-way valve is difficult to clean and maintain conveniently due to its structure. Once the problem of impurity accumulation occurs, it is often necessary to disassemble the entire three-way valve for cleaning or replacement, which is not only cumbersome to operate and increase the cost and time of operation and maintenance, but may also cause secondary damage to the equipment during the disassembly process, further affecting the reliability and stability of the electrical equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a three-way valve for online calibration of SF6 density relay in order to solve at least one of the above technical problems.

[0004] The present invention achieves the above-mentioned purpose through the following technical scheme: A three-way valve used for online calibration of SF density relay, comprising a three-way valve body and a port A and a port B symmetrically fixedly connected to the surface of the three-way valve body, a port C is also arranged on one side surface of the three-way valve body, a valve stem is rotatably connected to the surface of the three-way valve body, and the valve stem is fixedly connected to a valve core arranged inside the three-way valve body, and an operating lever is fixedly connected to the end of the valve stem; A cleaning filter assembly is provided between the three-way valve body and the port C, and the cleaning filter assembly includes a hollow cylinder fixedly connected to one end of the port C, a filter plate fixedly connected to the inside of the hollow cylinder, and a support column, a fixed plate, a first rotating rod, an L-shaped plate and bristles for cleaning impurities on the surface of the filter plate; A backwashing assembly is arranged between the three-way valve body and the hollow cylinder, and the backwashing assembly includes an annular water tank fixedly connected to the surface of the three-way valve body, a connecting pipe fixedly connected to the inner surface of the annular water tank, and a micro water pump, a water pipe, an annular water pipe and a high-pressure nozzle for backwashing the surface of the filter plate.

[0005] As a further solution of the present invention: circular through holes are symmetrically opened on both sides of the surface of the hollow cylinder, and the inner surfaces of the circular through holes are fixedly connected with support columns in a circular array, and a fixed disk is concentrically arranged in the circular through holes. The support column is fixedly connected between the hollow cylinder and the fixed disk, and a first rotating rod is rotatably connected between the two fixed disks. The first rotating rod penetrates the filter plate and is rotatably connected to the filter plate, and the surface of the first rotating rod is fixedly connected with three L-shaped plates in a circular array, and the surface of each L-shaped plate is fixedly connected with bristles.

[0006] As a further solution of the present invention: the bristles are in contact with the filter plate and the surface of the hollow cylinder respectively.

[0007] As a further solution of the present invention: a second rotating rod is inserted into the surface of the hollow cylinder, the second rotating rod is rotatably connected to the hollow cylinder, the bottom end of the second rotating rod extends to the interior of the hollow cylinder and is fixedly connected to the first bevel gear arranged inside the hollow cylinder, the surface of the first rotating rod is fixedly sleeved with the second bevel gear, the first bevel gear and the second bevel gear are meshingly connected, the top end of the second rotating rod extends to the outside of the hollow cylinder and is fixedly connected to the first pulley arranged on the outside of the hollow cylinder, the surface of the valve stem is fixedly sleeved with the second pulley, and the first pulley and the second pulley are connected by belt drive.

[0008] As a further solution of the present invention: the outer side covers of the first pulley and the second pulley are provided with protective covers, and the protective covers are fixedly connected to the surfaces of the three-way valve body and the hollow cylinder through connecting blocks.

[0009] As a further solution of the present invention: a discharge port is provided on the bottom surface of the hollow cylinder at the right side of the filter plate, a magnet is symmetrically fixedly connected to the inner wall of the discharge port, a plug is inserted inside the discharge port, the plug is made of magnetic material, and the plug is connected to the hollow cylinder through the magnet.

[0010] As a further solution of the present invention: the connecting pipe and the hollow cylinder are fixedly connected, a micro water pump is fixedly installed on the surface of the annular water tank, the water inlet end of the micro water pump extends to the interior of the annular water tank through the water inlet pipe, the water outlet end of the micro water pump is fixedly connected to a water supply pipe, the end of the water supply pipe is fixedly connected to an annular water pipe, the surface of the annular water pipe is fixedly connected with a plurality of high-pressure nozzles in a circular array, the high-pressure nozzles are inserted on the surface of the hollow cylinder and fixedly connected to the hollow cylinder, and the water spraying end of the high-pressure nozzles extends to the interior of the hollow cylinder.

[0011] As a further solution of the present invention: a water injection pipe with a sealing plug at the end is fixedly connected to the surface of the annular water tank.

[0012] The beneficial effects of the present invention are: The present invention is provided with a cleaning filter assembly, which can prevent the three-way valve body from being blocked. Impurities may accumulate in the internal structure of the three-way valve, such as the valve core, valve seat and other key parts, narrowing or even blocking the gas passage, affecting the normal circulation of the gas. The filter plate can block impurities, ensure the smooth passage of gas, make the equipment work stably, and smoothly switch the gas path connection state to ensure the normal operation of the calibration work. On the other hand, it is beneficial to ensure the safety of equipment. The presence of impurities may interfere with the normal function of SF6 gas. Pure SF6 gas has good insulation performance. Impurities will reduce the insulation performance and may cause insulation breakdown and other faults in the equipment. Filtering impurities can reduce this risk.

[0013] The present invention can maintain the filtering efficiency of the filter plate when in use by arranging a support column, a fixed plate, a first rotating rod, an L-shaped plate and bristles. When filtering SF6 gas, impurities will continuously accumulate on the surface of the filter plate. Long-term accumulation will clog the pores of the filter plate, resulting in a slow gas passage speed and poor filtering effect. By timely cleaning impurities with the bristles, the pores of the filter plate can be kept unobstructed, allowing the gas to pass smoothly, ensuring that the filter plate continuously and effectively filters impurities; at the same time, the interior of the hollow cylinder can also be maintained clean, impurities can be avoided from adhering to the inner wall of the hollow cylinder, and excessive accumulation of impurities can be prevented from falling back into the filtered gas. Cleaning the inner wall of the hollow cylinder with the bristles helps to maintain the cleanliness of the internal environment of the hollow cylinder, ensuring that the gas completes filtering and subsequent processes in a relatively clean space.

[0014] 3. The present invention provides a second rotating rod, a first bevel gear, a second bevel gear, a first pulley and a second pulley. First, the operation is convenient. During the routine operation of switching the three-way valve passage, the action of cleaning the bristles can be triggered at the same time. There is no need to arrange additional cleaning steps separately, which saves time and manpower. The operator does not need to stop other work specifically for cleaning, or to execute complex cleaning instructions, which makes the use and maintenance of the equipment more efficient. Second, the continuity of equipment performance is ensured. By cleaning the filter plate in time, it can effectively prevent excessive accumulation of impurities on the filter plate. Third, the integration and coordination of the equipment are improved. The linkage between the valve stem, the second rotating rod and the first rotating rod is used to organically combine the two functions of passage switching and equipment cleaning, which reflects the integrity and coordination of the equipment design, helps to reduce the complexity of the equipment, avoids potential failure points caused by too many independent functional modules, and improves the reliability of equipment operation.

[0015] 4. The back flushing component provided in the present invention can deeply clean the filter plate. For some tightly attached stubborn impurities, it may not be possible to completely remove them by brushing only. The back flushing component uses water pressure to flush these difficult-to-clean impurities from the surface of the filter plate, thereby achieving more thorough cleaning and ensuring the filtering performance of the filter plate.

[0016] 5. The present invention can clean up the cleaned impurities in time by arranging a plug at the bottom of the hollow cylinder, without the need to disassemble the entire three-way valve for cleaning or replacement. The operation is simple, the operation and maintenance cost and time are reduced, and secondary damage to the equipment during the disassembly process is avoided, thereby further improving the reliability and stability of the electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The overall structure of the present invention is shown in FIG. Figure 1 ; Figure 2 The overall structure of the present invention is shown in FIG. Figure 2 ; Figure 3 The overall structure of the present invention is shown in FIG. Figure 3 ; Figure 4 The cross-sectional structure of the present invention is shown in FIG. Figure 1 ; Figure 5 The cross-sectional structure of the present invention is shown in FIG. Figure 2 ; Figure 6 It is a structural schematic diagram of the backwashing component in the present invention; Figure 7 The cross-sectional structure of the hollow tube in the present invention is shown in FIG. Figure 1 ; Figure 8 The cross-sectional structure of the hollow tube in the present invention is shown in FIG. Figure 2 ; Fig. 9 This is a schematic diagram of the connection structure between the filter plate and the bristles in the present invention; Fig.10 It is a schematic diagram of the connection structure between the filter plate and the hollow cylinder in the present invention.

[0018] In the figure: 1. three-way valve body, 2. valve stem, 3. joystick, 4. port A, 5. port B, 6. port C, 7. cleaning filter assembly, 71. hollow cylinder, 72. support column, 73. fixed plate, 74. first rotating rod, 75. filter plate, 76. second rotating rod, 77. first pulley, 78. first bevel gear, 79. second bevel gear, 710. circular through hole, 711. three L-shaped plates, 712. bristles, 713. discharge port, 714. magnet, 715. plug, 716. second pulley, 717. belt, 718. protective cover, 8. backwash assembly, 81. annular water tank, 82. water injection pipe, 83. connecting pipe, 84. micro water pump, 85. water pipe, 86. annular water pipe, 87. high-pressure nozzle. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0020] like Figures 1 to 10 As shown, a three-way valve used for online calibration of SF6 density relays comprises a three-way valve body 1 and ports A4 and B5 symmetrically fixedly connected to the surface of the three-way valve body 1, a port C6 is further provided on one side surface of the three-way valve body 1, a valve stem 2 is rotatably connected to the surface of the three-way valve body 1, and the valve stem 2 is fixedly connected to a valve core provided inside the three-way valve body 1, and an operating lever 3 is fixedly connected to the end of the valve stem 2; A cleaning filter assembly 7 is provided between the three-way valve body 1 and the port C6. The cleaning filter assembly 7 includes a hollow cylinder 71 fixedly connected to one end of the port C6, a filter plate 75 fixedly connected to the inside of the hollow cylinder 71, and a support column 72, a fixed plate 73, a first rotating rod 74, an L-shaped plate 711 and bristles 712 for cleaning impurities on the surface of the filter plate 75. The filter plate 75 can block impurities to ensure smooth passage of gas, so that the equipment can work stably, and the gas path connection state can be smoothly switched to ensure the normal progress of the calibration work; A backwashing assembly 8 is arranged between the three-way valve body 1 and the hollow cylinder 71. The backwashing assembly 8 includes an annular water tank 81 fixedly connected to the surface of the three-way valve body 1, a connecting pipe 83 fixedly connected to the inner surface of the annular water tank 81, and a micro water pump 84, a water pipe 85, an annular water pipe 86 and a high-pressure nozzle 87 for backwashing the surface of the filter plate 75. The backwashing assembly 8 uses water pressure to flush impurities that are difficult to clean from the surface of the filter plate 75, thereby achieving more thorough cleaning and ensuring the filtering performance of the filter plate 75. Example

[0021] In addition to all the technical features of the first embodiment, this embodiment also includes: Circular through holes 710 are symmetrically provided on both sides of the surface of the hollow cylinder 71. The inner surfaces of the circular through holes 710 are fixedly connected with support columns 72 in a circular array. A fixed disk 73 is concentrically arranged in the circular through holes 710. The support columns 72 are fixedly connected between the hollow cylinder 71 and the fixed disk 73. A first rotating rod 74 is rotatably connected between the two fixed disks 73. The first rotating rod 74 penetrates the filter plate 75 and is rotatably connected to the filter plate 75. The surface of the first rotating rod 74 is fixedly connected with three L-shaped plates 711 in a circular array. The surface of each L-shaped plate 711 is fixedly connected with bristles 712. The bristles 712 are used to clean impurities in time, so that the pores of the filter plate 75 can be kept unobstructed, allowing gas to pass smoothly, thereby ensuring that the filter plate 75 continuously and effectively filters impurities; at the same time, the cleanliness of the interior of the hollow cylinder 71 can be maintained to avoid impurities adhering to the inner wall of the hollow cylinder 71, and to prevent excessive accumulation of impurities from falling back into the filtered gas.

[0022] The bristles 712 are in contact with the surfaces of the filter plate 75 and the hollow cylinder 71 respectively, and the bristles 712 can be used to effectively clean impurities on the surfaces of the filter plate 75 and the hollow cylinder 71 .

[0023] A second rotating rod 76 is inserted into the surface of the hollow cylinder 71, and the second rotating rod 76 is rotatably connected to the hollow cylinder 71. The bottom end of the second rotating rod 76 extends to the interior of the hollow cylinder 71 and is fixedly connected to the first bevel gear 78 arranged inside the hollow cylinder 71. The surface of the first rotating rod 74 is fixedly sleeved with a second bevel gear 79, and the first bevel gear 78 and the second bevel gear 79 are meshed and connected. The top end of the second rotating rod 76 extends to the outside of the hollow cylinder 71 and is fixedly connected to the first pulley 77 arranged on the outside of the hollow cylinder 71. The surface of the valve stem 2 is fixedly sleeved with a second pulley 716, and the first pulley 77 and the second pulley 716 are connected by belt 717. The linkage between the valve stem 2, the second rotating rod 76 and the first rotating rod 74 is utilized to organically combine the two functions of passage switching and equipment cleaning, which reflects the integrity and coordination of the equipment design, helps to reduce the complexity of the equipment, avoids potential failure points caused by too many independent functional modules, and improves the reliability of equipment operation.

[0024] The outer covers of the first pulley 77 and the second pulley 716 are provided with protective covers 718, which are fixedly connected to the surfaces of the three-way valve body 1 and the hollow cylinder 71 through connecting blocks, and can play a certain protective role on the belt 717 and extend the service life of the belt 717. Example

[0025] In addition to all the technical features of the first embodiment, this embodiment also includes: A discharge port 713 is provided on the bottom surface of the hollow cylinder 71 at the right side of the filter plate 75. A magnet 714 is symmetrically fixedly connected to the inner wall of the discharge port 713. A plug 715 is inserted into the discharge port 713. The plug 715 is made of magnetic material. The plug 715 is connected to the hollow cylinder 71 through the magnet 714, so that the cleaned impurities can be cleaned in time without disassembling the entire three-way valve for cleaning or replacement. The operation is simple, which reduces the operation and maintenance cost and time, avoids secondary damage to the equipment during the disassembly process, and further improves the reliability and stability of the electrical equipment. Example

[0026] The connecting pipe 83 is fixedly connected to the hollow cylinder 71, and a micro water pump 84 is fixedly installed on the surface of the annular water tank 81. The water inlet end of the micro water pump 84 extends to the inside of the annular water tank 81 through the water inlet pipe, and the water outlet end of the micro water pump 84 is fixedly connected to a water delivery pipe 85, and the end of the water delivery pipe 85 is fixedly connected to an annular water pipe 86. The surface of the annular water pipe 86 is in a circular array and fixedly connected with a plurality of high-pressure nozzles 87. The high-pressure nozzles 87 are inserted on the surface of the hollow cylinder 71 and are fixedly connected to the hollow cylinder 71. The water spraying end of the high-pressure nozzles 87 extends to the inside of the hollow cylinder 71. The backwashing component 8 uses water pressure to flush these difficult-to-clean impurities from the surface of the filter plate 75, thereby achieving more thorough cleaning and ensuring the filtering performance of the filter plate 75.

[0027] A water injection pipe 82 with a sealing plug at the end is fixedly connected to the surface of the annular water tank 81 , so as to facilitate timely addition of water to the annular water tank 81 .

[0028] Working principle: When using this three-way valve, first tighten the connection pipe between port A4 and SF6 density relay through threads, install the sealing gasket, then connect the flange of port C6 with the SF6 gas line flange of the electrical equipment, install the metal sealing gasket and tighten it with bolts, and finally connect the quick-plug connector of port B5 with the calibration instrument; During normal operation, the three-way valve body 1 is in the initial state, and the SF6 gas in the electrical equipment can work normally through port A4 under the monitoring of the density relay.

[0029] When online calibration is required, the calibration personnel rotate the joystick 3 on the top of the valve stem 2 to drive the valve core to rotate, so that SF6 gas flows into the calibration instrument from port B5. The calibration instrument calibrates the density relay according to the preset program, such as detecting the pressure value, alarm signal and other parameters, and compares and analyzes them with the standard values ​​to achieve the switching of the gas circuit between port A4, port B5 and port C6 to meet different calibration and equipment operation requirements; When the gas flows through the three-way valve body 1, the impurities in the gas are first filtered through the filter plate 75, and the pure gas passes through the filter plate 75, while the impurities are blocked on the right side of the filter plate 75. When the inspection is completed, the inspector rotates the valve stem 2. At this time, the valve stem 2 drives the second pulley 716 to rotate, and the second pulley 716 rotates and then drives the first pulley 77 to rotate synchronously through the belt 717. The first pulley 77 rotates and then drives the first bevel gear 78 and the second bevel gear 79 to rotate successively. The second bevel gear 79 rotates and then drives the first rotating rod 74 to rotate. The first rotating rod 74 rotates and then drives the L-shaped plate 711 and the bristles 712 to rotate. The bristles 712 are used to clean the filter plate 75 and the filter plate 75. Cleaning the impurities attached to the surface of the hollow cylinder 71 can keep the pores of the filter plate 75 unobstructed, allowing the gas to pass smoothly, ensuring that the filter plate 75 continuously and effectively filters impurities; at the same time, the cleanliness of the inside of the hollow cylinder 71 can be maintained to prevent impurities from being attached to the inner wall of the hollow cylinder 71, and prevent excessive accumulation of impurities from falling back into the filtered gas. At the same time, the linkage between the valve stem 2, the second rotating rod 76 and the first rotating rod 74 is used to organically combine the two functions of passage switching and equipment cleaning, which reflects the integrity and synergy of the equipment design, helps to reduce the complexity of the equipment, avoids potential failure points caused by too many independent functional modules, and improves the reliability of equipment operation; After the calibration is completed, the micro water pump 84 is started, and the clean water in the annular water tank 81 is transported to the annular water pipe 86 through the water pipe 85 by the micro water pump 84, and finally sprayed to one side of the filter plate 75 by the high-pressure nozzle 87. The stubborn impurities attached to the surface of the filter plate 75 can be cleaned by water pressure, so as to achieve more thorough cleaning, ensure the filtering performance of the filter plate 35, prevent the three-way valve body 1 from being blocked, and prevent impurities from accumulating in the internal structure of the three-way valve, such as the valve core, valve seat and other key parts, so that the gas passage becomes narrower or even blocked, and the normal circulation of the gas is avoided. By setting the filter plate 75, impurities can be blocked to ensure the smooth passage of gas, so that the equipment can work stably, and the gas path connection state can be smoothly switched to ensure the normal progress of the calibration work; Finally, the plug 715 is opened to clean the cleaned impurities in time without disassembling the entire three-way valve for cleaning or replacement. The operation is simple, which reduces the operation and maintenance cost and time, avoids secondary damage to the equipment during the disassembly process, and further improves the reliability and stability of the electrical equipment.

[0030] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0031] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A three-way valve for online calibration of an SF6 density relay, comprising a three-way valve body (1) and a port A (4) and a port B (5) symmetrically fixedly connected to the surface of the three-way valve body (1); a port C (6) is further provided on one side surface of the three-way valve body (1); a valve stem (2) is rotatably connected to the surface of the three-way valve body (1); the valve stem (2) is fixedly connected to a valve core provided inside the three-way valve body (1); and an operating lever (3) is fixedly connected to the end of the valve stem (2); Features: A cleaning filter assembly (7) is provided between the three-way valve body (1) and the port C (6), the cleaning filter assembly (7) comprising a hollow cylinder (71) fixedly connected to one end of the port C (6), a filter plate (75) fixedly connected to the interior of the hollow cylinder (71), and a support column (72) for cleaning impurities on the surface of the filter plate (75), a fixed plate (73), a first rotating rod (74), an L-shaped plate (711) and bristles (712); A backwashing assembly (8) is provided between the three-way valve body (1) and the hollow cylinder (71), the backwashing assembly (8) comprising an annular water tank (81) fixedly connected to the surface of the three-way valve body (1), a connecting pipe (83) fixedly connected to the inner surface of the annular water tank (81), and a micro water pump (84) for backwashing the surface of the filter plate (75), a water delivery pipe (85), an annular water pipe (86) and a high-pressure nozzle (87).

2. The three-way valve used for online calibration of SF6 density relay according to claim 1 is characterized in that: Circular through holes (710) are symmetrically provided on both sides of the surface of the hollow cylinder (71), and the inner surface of the circular through hole (710) is fixedly connected to a support column (72) in a circular array. A fixed disk (73) is concentrically arranged in the circular through hole (710), and the support column (72) is fixedly connected between the hollow cylinder (71) and the fixed disk (73). A first rotating rod (74) is rotatably connected between the two fixed disks (73), and the first rotating rod (74) passes through the filter plate (75) and is rotatably connected to the filter plate (75). Three L-shaped plates (711) are fixedly connected to the surface of the first rotating rod (74) in a circular array, and bristles (712) are fixedly connected to the surface of each L-shaped plate (711).

3. The three-way valve used for online calibration of SF6 density relay according to claim 2 is characterized in that: The bristles (712) are in contact with the surfaces of the filter plate (75) and the hollow cylinder (71), respectively.

4. The three-way valve used for online calibration of SF6 density relay according to claim 1 is characterized in that: A second rotating rod (76) is inserted into the surface of the hollow cylinder (71), and the second rotating rod (76) is rotatably connected to the hollow cylinder (71). The bottom end of the second rotating rod (76) extends to the interior of the hollow cylinder (71) and is fixedly connected to a first bevel gear (78) arranged inside the hollow cylinder. A second bevel gear (79) is fixedly sleeved on the surface of the first rotating rod (74), and the first bevel gear (78) and the second bevel gear (79) are meshingly connected. The top end of the second rotating rod (76) extends to the outside of the hollow cylinder (71) and is fixedly connected to a first pulley (77) arranged on the outside of the hollow cylinder (71). A second pulley (716) is fixedly sleeved on the surface of the valve stem (2), and the first pulley (77) and the second pulley (716) are connected by a belt (717).

5. The three-way valve used for online calibration of SF6 density relay according to claim 4 is characterized in that: The outer side covers of the first pulley (77) and the second pulley (716) are provided with protective covers (718), and the protective covers (718) are fixedly connected to the surfaces of the three-way valve body (1) and the hollow cylinder (71) via a connecting block.

6. The three-way valve used for online calibration of SF6 density relay according to claim 1 is characterized in that: A discharge port (713) is provided on the bottom surface of the hollow cylinder (71) at the right side of the filter plate (75); a magnet (714) is symmetrically fixedly connected to the inner wall surface of the discharge port (713); a plug (715) is inserted into the interior of the discharge port (713); the plug (715) is made of magnetic material, and the plug (715) is connected to the hollow cylinder (71) via the magnet (714).

7. The three-way valve used for online calibration of SF6 density relay according to claim 1 is characterized in that: The connecting pipe (83) is fixedly connected to the hollow cylinder (71); a micro water pump (84) is fixedly mounted on the surface of the annular water tank (81); a water inlet end of the micro water pump (84) extends to the interior of the annular water tank (81) through a water inlet pipe; a water outlet end of the micro water pump (84) is fixedly connected to a water delivery pipe (85); an end of the water delivery pipe (85) is fixedly connected to an annular water pipe (86); a plurality of high-pressure nozzles (87) are fixedly connected to the surface of the annular water pipe (86) in a circular array; the high-pressure nozzles (87) are inserted on the surface of the hollow cylinder (71) and are fixedly connected to the hollow cylinder (71); a water spraying end of the high-pressure nozzles (87) extends to the interior of the hollow cylinder (71).

8. The three-way valve used for online calibration of SF6 density relay according to claim 1 is characterized in that: A water injection pipe (82) having a sealing plug at the end is fixedly connected to the surface of the annular water tank (81).

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