Transformer insulating oil sampling device and method

Abstract

The invention relates to the technical field of transformer insulating oil sampling, in particular to a transformer insulating oil sampling device and method. The transformer insulating oil sampling device comprises a four-way valve, and a first interface of the four-way valve is connected with a transformer oil outlet; a second interface of the four-way valve is connected with a waste oil barrel; a third interface of the four-way valve is connected with an empty pipeline; a fourth interface of the four-way valve is connected with an inlet of the water-gas dual-purpose pump; a liquid outlet of the water-gas dual-purpose pump is connected with the side wall of the temporary storage barrel; and a gas outlet of the water-gas dual-purpose pump is connected with the top surface of the temporary storage barrel. Compared with the prior art, manual operation is reduced, the repeated operation time is shortened, the working efficiency is improved, the use amount of oil taking consumption is reduced, and meanwhile, the harm of insulating oil to the body of sampling personnel is reduced. The transformer insulating oil sampling method adopts the transformer insulating oil sampling device.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer insulating oil sampling, and in particular to a transformer insulating oil sampling device and a transformer insulating oil sampling method. Background Art

[0002] Transformer insulating oil is an indispensable liquid insulating medium in a transformer. It plays multiple roles such as insulation, heat dissipation, and arc extinction in the transformer. It can effectively isolate the electrical connection between the high- and low-voltage windings, take away heat, and quickly extinguish the arc to prevent the expansion of faults and damage to equipment.

[0003] When the transformer is in normal operation, since the oil and solid insulation will gradually age, deteriorate, and decompose a very small amount of gases, mainly hydrogen, methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide, etc. Therefore, it is of great significance to analyze the dissolved gas components in the transformer insulating oil. Currently, the commonly used method for analyzing the dissolved gas components in the internal insulating oil of a transformer is the chromatographic analysis of the transformer insulating oil. And in this test, taking oil is one of the basic tasks, and whether the taken sample is true and reliable will directly affect the accuracy of the chromatographic analysis result.

[0004] With the gradual expansion of the scale of the substation, the workload of the transformer oil chromatographic test also increases accordingly, and the existing sampling technology is completed manually. Among them, manual sampling requires a large number of repeated operations, and the consumption of consumables used by the sampling personnel is also very large, and the sampling cost is relatively high. In addition, transformer insulating oil is harmful to the human body, and long-term manual sampling will have a certain impact on physical health. Summary of the Invention

[0005] In view of the problems of large labor intensity, high cost, and health impact caused by manual operation in the current sampling of transformer insulating oil, the present invention provides a transformer insulating oil sampling device.

[0006] To solve the above problems, the technical solution adopted by the present invention is A transformer insulating oil sampling device includes a four-way valve. The first interface of the four-way valve is connected to the transformer oil drain port; the second interface of the four-way valve is connected to the waste oil barrel; the third interface of the four-way valve is connected to an empty pipeline; the fourth interface of the four-way valve is connected to the inlet of a water-air dual-purpose pump. The liquid outlet of the water-air dual-purpose pump is connected to the side wall of a temporary storage cylinder, and the gas outlet of the water-air dual-purpose pump is connected to the top surface of the temporary storage cylinder. Through the settings of the water-air dual-purpose pump and the four-way valve, the waste oil in the temporary storage cylinder can be discharged in time; insulating oil can be extracted from the transformer and discharged into the temporary storage cylinder, and then the insulating oil can be discharged from the temporary storage cylinder into the sampling tube; the temporary storage cylinder and the four-way valve can also be backwashed, which is convenient for subsequent use and ensures the accuracy of subsequent sampling. It reduces manual operation, reduces the repetitive operation time, improves work efficiency, reduces the usage amount of sampling consumables, and at the same time reduces the physical harm of insulating oil to sampling personnel.

[0007] Preferably, a valve one is connected to the liquid outlet of the water-air dual-purpose pump; a filter is connected to the valve one; the filter is connected to the side wall of the temporary storage cylinder; the gas outlet of the water-air dual-purpose pump is connected to the top surface of the temporary storage cylinder through a valve two; a drain pipe is provided in the middle of the bottom surface of the temporary storage cylinder; a valve three is provided in the middle of the drain pipe; the transformer insulating oil sampling device further includes a controller; the controller is electrically connected to the four-way valve, the water-air dual-purpose pump, the valve one, the valve two, and the valve three. Through the setting of the controller, the manual operation labor amount is further reduced, and the physical harm of insulating oil to sampling personnel is further reduced.

[0008] Preferably, the first interface and the fourth interface are coaxially arranged and are arranged in a first plane; the second interface and the third interface are coaxially arranged and are arranged in a second plane; the first plane is perpendicular to the second plane. When in use, the first plane is set horizontally and the second plane is set vertically, which is convenient for the smooth operation of the water-air dual-purpose pump and convenient for the waste oil barrel to collect waste oil.

[0009] Preferably, the four-way valve includes a valve housing that is integrally cylindrical; the first interface, the second interface, the third interface, and the fourth interface are evenly arranged on the middle side wall of the valve housing along the circumferential direction; a motor one is provided on the outer wall of one end of the valve housing, and a motor two is provided on the outer wall of the other end of the valve housing; a first valve core is sleeved inside the valve housing; the first valve core is connected to the motor one; a second valve core is sleeved inside the first valve core; the second valve core is integrally cylindrical; the second valve core is connected to the motor two; a relief groove is provided on the middle side wall of the first valve core; a T-shaped communication hole is provided in the middle of the second valve core. Through the actions of the motor one and the motor two, the first valve core and the second valve core are driven to rotate coaxially. Through the cooperation of the T-shaped communication hole and the relief groove, the connection of the first interface, the second interface, the third interface, and the fourth interface is ensured.

[0010] Preferably, one end of the first valve core is provided with a first connecting shaft; the first connecting shaft penetrates through the valve housing and then connects to the first motor; the T-shaped communication hole includes a first through hole, a second through hole, and a third through hole; the first through hole and the third through hole are coaxially arranged; a circular truncated cone is arranged outside the first through hole; one end of the second valve core far from the first connecting shaft is provided with a second connecting shaft; the second connecting shaft penetrates through the first valve core and the valve housing and then connects to the second motor. The setting of the circular truncated cone can ensure the accuracy when connecting two of the first interface, the second interface, the third interface, and the fourth interface.

[0011] Preferably, there is a clearance fit between the first valve core and the valve housing; there is a clearance fit between the first valve core and the second valve core. This facilitates the smooth movement of the first valve core and the second valve core.

[0012] Preferably, a semi-circular ring convex platform is arranged on the side wall of the middle part of the second valve core; the semi-circular ring convex platform is coaxially arranged with the second through hole; the semi-circular ring convex platform faces the side of the circular truncated cone. The setting of the semi-circular ring convex platform can limit the rotation of the first valve core or the second valve core and ensure the accurate movement of the first valve core and the second valve core.

[0013] On the other hand, the present invention also provides a method for sampling transformer insulating oil, using the above-mentioned transformer insulating oil sampling device, including the following steps: S1. Drain waste oil: Connect the drain pipe to the waste oil barrel; the controller controls the four-way valve to act in the first position, controls the third interface to communicate with the fourth interface; closes valve one, and opens valve two and valve three; then the controller controls the water-air dual-purpose pump to act. The water-air dual-purpose pump extracts air from the empty pipe and injects it into the temporary storage cylinder, and uses the air flow to drain the residual waste oil in the temporary storage cylinder into the waste oil barrel through the drain pipe. S2. Extract oil sample: The controller controls the four-way valve to act in the second position, controls the first interface to communicate with the fourth interface; closes valve two and valve three, and opens valve one; then the controller controls the water-air dual-purpose pump to act. The water-air dual-purpose pump extracts insulating oil from the transformer oil drain port through the first interface, and injects the insulating oil into the temporary storage cylinder through valve one and the filter. S3. Save oil sample: The controller controls the four-way valve to act in the first position, controls the third interface to communicate with the fourth interface; manually hold the sampling tube and place it at the outlet of the drain pipe; the controller controls valve one and valve three to open, and controls valve two to close; then controls the water-air dual-purpose pump to act, extracts gas from the empty pipe and injects it into the temporary storage cylinder, and injects the insulating oil into the sampling tube through the drain pipe.

[0014] Preferably, it further includes step S4: The controller controls the four-way valve to act in the third position, controls the fourth interface to communicate with the second interface; a flushing liquid is placed in the temporary storage cylinder; the controller controls valve two and valve three to close, and controls valve one to open; then controls the water-air dual-purpose pump to act, injects the flushing liquid in the temporary storage cylinder into the four-way valve, and then into the waste oil barrel to perform back flushing on the temporary storage cylinder and the four-way valve.

[0015] As can be seen from the above technical solutions, the advantages of the present invention are as follows: The present solution provides a transformer insulating oil sampling device. Through the setting of a water-air dual-purpose pump and a four-way valve, the waste oil in the temporary storage cylinder can be discharged in a timely manner; the insulating oil can be extracted from the transformer and discharged into the temporary storage cylinder, and then the insulating oil can be discharged from the temporary storage cylinder into the sampling pipe; the temporary storage cylinder and the four-way valve can also be backflushed, which is convenient for subsequent use and ensures the accuracy of subsequent sampling. Furthermore, a transformer insulating oil sampling method of the present invention reduces manual operation, reduces the repetitive operation time, improves work efficiency, reduces the usage amount of sampling consumables, and at the same time reduces the physical harm of insulating oil to sampling personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a schematic structural diagram of the present invention.

[0018] Figure 2 It is a schematic structural diagram of the four-way valve of the present invention.

[0019] Figure 3 It is an exploded structural diagram of the four-way valve of the present invention.

[0020] Figure 4 It is a schematic structural diagram of the first valve core of the present invention.

[0021] Figure 5 It is a schematic structural diagram of the second valve core of the present invention Figure 1 .

[0022] Figure 6 It is a schematic structural diagram of the second valve core of the present invention Figure 2 .

[0023] Figure 7 It is a schematic cross-sectional structural diagram of the four-way valve of the present invention at the third position.

[0024] Figure 8 It is a schematic cross-sectional structural diagram of the four-way valve of the present invention at the second position.

[0025] Figure 9 It is a schematic cross-sectional structural diagram of the four-way valve of the present invention at the first position.

[0026] MAIN REFERENCE NUMERAL DESCRIPTION 1 - Four - way valve, 2 - Transformer, 3 - Spent oil barrel, 4 - Empty pipeline, 5 - Water - air dual - use pump, 6 - Temporary storage cylinder, 7 - Valve 1, 8 - Filter, 9 - Valve 2, 10 - Oil discharge pipe, 11 - Valve 3; 101 - First interface, 102 - Second interface, 103 - Third interface, 104 - Fourth interface, 105 - Valve housing, 106 - Motor 1, 107 - Motor 2, 108 - First valve core, 109 - Second valve core, 110 - Relief groove, 111 - First through - hole, 112 - Second through - hole, 113 - Third through - hole, 114 - Circular truncated cone, 115 - First connecting shaft, 116 - Second connecting shaft, 117 - Semi - circular convex platform. Detailed implementation manner

[0027] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the specific embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this patent.

[0028] As Figure 1 shown, a sampling device for transformer insulating oil includes a four - way valve 1. The four - way valve 1 includes a valve housing 105 that is integrally cylindrical. The first interface 101, the second interface 102, the third interface 103, and the fourth interface 104 are uniformly arranged on the middle side wall of the valve housing 105 along the circumferential direction. The first interface 101 and the fourth interface 104 are coaxially arranged and are arranged in a first plane, and the first plane is horizontally arranged. The second interface 102 and the third interface 103 are coaxially arranged and are arranged in a second plane, and the second plane is vertically arranged. The first plane is perpendicular to the second plane. The first interface 101 of the four - way valve 1 is connected to the oil discharge port of the transformer 2. The second interface 102 of the four - way valve 1 is connected to the spent oil barrel 3. The third interface 103 of the four - way valve 1 is connected to the empty pipeline 4. The fourth interface 104 of the four - way valve 1 is connected to the inlet of the water - air dual - use pump 5. The liquid outlet of the water - air dual - use pump 5 is connected to the side wall of the temporary storage cylinder 6. The gas outlet of the water - air dual - use pump 5 is connected to the top surface of the temporary storage cylinder 6.

[0029] In the above setting, the liquid outlet of the water-air dual-use pump 5 is connected to a first valve 7; the first valve 7 is connected to a filter 8; the filter 8 is connected to the side wall of the temporary storage cylinder 6; the gas outlet of the water-air dual-use pump 5 is connected to the top surface of the temporary storage cylinder 6 through a second valve 9; a drain pipe 10 is provided in the middle of the bottom surface of the temporary storage cylinder 6; a third valve 11 is provided in the middle of the drain pipe 10; the transformer insulating oil sampling device further includes a controller; the controller is electrically connected to the four-way valve 1, the water-air dual-use pump 5, the first valve 7, the second valve 9 and the third valve 11. Through the setting of the controller, the manual operation workload is further reduced, and the physical harm of the insulating oil to the sampling personnel is further reduced.

[0030] As Figures 2 - 6 shown, a first motor 106 is provided on the outer wall of one end of the valve housing 105 of the four-way valve 1, and a second motor 107 is provided on the outer wall of the other end of the valve housing 105; a first valve core 108 is sleeved inside the valve housing 105; the first valve core 108 is connected to the first motor 106; a second valve core 109 is sleeved inside the first valve core 108; the second valve core 109 is integrally arranged in a cylindrical shape; the second valve core 109 is connected to the second motor 107; a relief groove 110 is provided on the middle side wall of the first valve core 108; a T-shaped communication hole is provided in the middle of the second valve core 109. Through the actions of the first motor 106 and the second motor 107, the first valve core 108 and the second valve core 109 are driven to rotate coaxially. Through the cooperation of the T-shaped communication hole and the relief groove 110, the communication of the first interface 101, the second interface 102, the third interface 103 and the fourth interface 104 is ensured. A first connecting shaft 115 is provided at one end of the first valve core 108; the first connecting shaft 115 penetrates through the valve housing 105 and then is connected to the first motor 106; the T-shaped communication hole includes a first through hole 111, a second through hole 112 and a third through hole 113; the first through hole 111 and the third through hole 113 are coaxially arranged; a circular ring platform 114 is provided outside the first through hole 111; a second connecting shaft 116 is provided at the end of the second valve core 109 far from the first connecting shaft 115; the second connecting shaft 116 penetrates through the first valve core 108 and the valve housing 105 and then is connected to the second motor 107. The setting of the circular ring platform 114 can ensure the accuracy when connecting two of the first interface 101, the second interface 102, the third interface 103 and the fourth interface 104. A semi-circular ring convex platform 117 is provided on the middle side wall of the second valve core 109; the semi-circular ring convex platform 117 is coaxially arranged with the second through hole 112; the semi-circular ring convex platform 117 faces the side of the circular ring platform 114. The setting of the semi-circular ring convex platform 117 can limit the rotation of the first valve core 108 or the second valve core 109 and ensure the accurate actions of the first valve core 108 and the second valve core 109.

[0031] Among them, there is a clearance fit between the first valve core 108 and the valve housing 105; there is a clearance fit between the first valve core 108 and the second valve core 109, which facilitates the smooth movement of the first valve core 108 and the second valve core 109.

[0032] For the method of sampling transformer insulating oil using the transformer insulating oil sampling device, before sampling, first drain the waste oil in the temporary storage cylinder 6, and connect the oil discharge pipe 10 to the waste oil barrel 3; the controller controls the four-way valve 1 to act in the first position, controls the third interface 103 to communicate with the fourth interface 104, that is, the inlet of the water-air dual-use pump 5 communicates with the empty pipe 4; close the first valve 7, and open the second valve 9 and the third valve 11; then the controller controls the water-air dual-use pump 5 to act, and the water-air dual-use pump 5 extracts air from the empty pipe 4 and injects it into the temporary storage cylinder 6, and uses the air flow to discharge the residual waste oil in the temporary storage cylinder 6 into the waste oil barrel 3 through the oil discharge pipe 10. Among them, the first position of the four-way valve 1 is as Figure 9 shown. The first valve core 108 closes the first interface 101 driven by the first motor 106. The second valve core 109 is driven by the second motor 107. The axis of the circular truncated cone 114 coincides with the axis of the fourth interface 104, and the axis of the semi-circular convex platform 117 coincides with the axis of the second interface 102. At this time, the third interface 103 communicates with the second through hole 112, and the first through hole 111 communicates with the fourth interface 104; and the semi-circular convex platform 117 abuts against the edge of the relief groove 110 of the first valve core 108; most of the gas entering from the third interface 103 flows out from the fourth interface 104 through the first through hole 111, and a small part enters the relief groove 110 and is blocked by the circular truncated cone 114.

[0033] When sampling the oil sample, the controller controls the four-way valve 1 to act in the second position, and the controller controls the first interface 101 to communicate with the fourth interface 104; close the second valve 9 and the third valve 11, and open the first valve 7; then the controller controls the water-air dual-use pump 5 to act, and the water-air dual-use pump 5 extracts insulating oil from the oil discharge port of the transformer 2 through the first interface 101, and injects the insulating oil into the temporary storage cylinder 6 through the first valve 7 and the filter 8. Among them, the second position of the four-way valve 1 is as Figure 8 shown. The first valve core 108 closes the third interface 103 driven by the first motor 106, that is, the first valve core 108 rotates counterclockwise by 90° based on the first position, and the second valve core 109 remains the same as the first position and does not move; at this time, the circular truncated cone 114 abuts against the edge of the relief groove 110. At this time, most of the insulating oil entering the four-way valve 1 from the first interface 101 enters the fourth interface 104 through the third through hole 113 and the first through hole 111; a small part of the insulating oil enters the relief groove 110 and is blocked by the semi-circular convex platform 117.

[0034] When storing the oil sample: the controller controls the four-way valve 1 to act in the first position, controls the third interface 103 to communicate with the fourth interface 104; manually hold the sampling tube and place it at the outlet of the oil discharge pipe 10; the controller controls the first valve 7 and the third valve 11 to open, and controls the second valve 9 to close; then controls the water-air dual-use pump 5 to act, extracts gas from the empty pipe 4 and injects it into the temporary storage cylinder 6, and injects the insulating oil into the sampling tube through the oil discharge pipe 10.

[0035] After a period of use, a flushing liquid is placed in the temporary storage tube 6, and the flushing liquid is gasoline, soap solution or other degreasing solvents (such as alcohol, trisodium phosphate, etc.). The controller controls the four-way valve 1 to move to the third position, and controls the fourth interface 104 to connect to the second interface 102; the controller controls the valve two 9 and the valve three 11 to close, and controls the valve one 7 to open; then controls the water-gas dual-purpose pump 5 to move, and pumps the flushing liquid in the temporary storage tube 6 into the four-way valve 1, and then into the waste oil barrel 3, so as to backwash the temporary storage tube 6 and the four-way valve 1.

[0036] The third position is Figure 7 As shown, the first valve core 108 closes the third interface 103 when driven by the motor 106; the second valve core 109 is driven by the motor 107, the axis of the circular ring stage 114 coincides with the axis of the second interface 102, and the semi-circular ring boss 117 contacts the edge of the clearance groove 110, that is, the second valve core 109 rotates 90° counterclockwise on the basis of the second position; at this time, the flushing liquid enters from the fourth interface 104, most of it enters the second interface 102 through the second through hole 112 and then through the first through hole 111; a small part enters the clearance groove 110 and is blocked by the circular ring stage 114.

[0037] In the above arrangement, the filter 8 is cylindrical in shape as a whole, and a filter net is arranged inside the cylinder, which can filter impurities and reduce oil foam in the insulating oil.

[0038] By setting up the water-gas dual-purpose pump 5 and the four-way valve 1, the waste oil in the temporary storage tube 6 can be discharged in time; the insulating oil can be drawn from the transformer 2 and discharged into the temporary storage tube 6, and then the insulating oil can be discharged into the sampling tube by the temporary storage tube 6; the temporary storage tube 6 and the four-way valve 1 can also be backwashed to facilitate subsequent use and ensure the accuracy of subsequent sampling. Manual operation is reduced, repeated operation time is reduced, work efficiency is improved, the use of oil consumables is reduced, and the physical harm of insulating oil to sampling personnel is reduced.

[0039] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transformer insulating oil sampling device, comprising a four-way valve (1), characterized in that: The first interface (101) of the four-way valve (1) is connected to the oil drain port of the transformer (2); the second interface (102) of the four-way valve (1) is connected to the waste oil barrel (3); the third interface (103) of the four-way valve (1) is connected to the empty pipe (4); the fourth interface (104) of the four-way valve (1) is connected to the inlet of the water-gas dual-purpose pump (5); the liquid outlet of the water-gas dual-purpose pump (5) is connected to the side wall of the temporary storage cylinder (6); and the gas outlet of the water-gas dual-purpose pump (5) is connected to the top surface of the temporary storage cylinder (6).

2. The transformer insulating oil sampling device according to claim 1, characterized in that: The liquid outlet of the water-gas dual-purpose pump (5) is connected to valve one (7); the valve one (7) is connected to a filter (8); the filter (8) is connected to the side wall of the temporary storage cylinder (6); the gas outlet of the water-gas dual-purpose pump (5) is connected to the top surface of the temporary storage cylinder (6) through valve two (9); an oil drain pipe (10) is provided in the middle of the bottom surface of the temporary storage cylinder (6); a valve three (11) is provided in the middle of the oil drain pipe (10); the transformer insulating oil sampling device also includes a controller; the controller is electrically connected to the four-way valve (1), the water-gas dual-purpose pump (5), valve one (7), valve two (9) and valve three (11).

3. The transformer insulating oil sampling device according to claim 2, characterized in that: The first interface (101) and the fourth interface (104) are coaxially arranged and arranged in a first plane; the second interface (102) and the third interface (103) are coaxially arranged and arranged in a second plane; and the first plane is perpendicular to the second plane.

4. The transformer insulating oil sampling device according to claim 3, characterized in that: The four-way valve (1) comprises a valve housing (105) which is cylindrical in shape as a whole; a first interface (101), a second interface (102), a third interface (103) and a fourth interface (104) are evenly arranged on a side wall in the middle of the valve housing (105) along a circumferential direction; a motor 1 (106) is arranged on an outer wall at one end of the valve housing (105), and a motor 2 (107) is arranged on an outer wall at the other end of the valve housing (105); a first valve core (108) is sleeved inside the valve housing (105); the first valve core (108) is connected to the motor 1 (106); a second valve core (109) is sleeved inside the first valve core (108); the second valve core (109) is cylindrical in shape as a whole; the second valve core (109) is connected to the motor 2 (107); a clearance groove (110) is arranged on the side wall in the middle of the first valve core (108); and a T-shaped connecting hole is arranged in the middle of the second valve core (109).

5. The transformer insulating oil sampling device according to claim 4, characterized in that: A first connecting shaft (115) is provided at one end of the first valve core (108); the first connecting shaft (115) passes through the valve housing (105) and is connected to the motor one (106); the T-shaped connecting hole comprises a first through hole (111), a second through hole (112) and a third through hole (113); the first through hole (111) and the third through hole (113) are coaxially arranged; a circular ring platform (114) is provided on the outer side of the first through hole (111); a second connecting shaft (116) is provided at one end of the second valve core (109) away from the first connecting shaft (115); the second connecting shaft (116) passes through the first valve core (108) and the valve housing (105) and is connected to the motor two (107).

6. The transformer insulating oil sampling device according to claim 5, characterized in that: There is a clearance fit between the first valve core (108) and the valve housing (105); there is a clearance fit between the first valve core (108) and the second valve core (109).

7. The transformer insulating oil sampling device according to claim 6, characterized in that: A semi-circular annular boss (117) is provided on the middle side wall of the second valve core (109); the semi-circular annular boss (117) is coaxially arranged with the second through hole (112); and the semi-circular annular boss (117) is arranged toward one side of the circular annular boss (114).

8. A transformer insulating oil sampling method, characterized in that: The transformer insulating oil sampling device according to claim 7 comprises the following steps: S1, draining waste oil: connecting the oil drain pipe (10) to the waste oil barrel (3); the controller controls the four-way valve (1) to operate in the first position, and controls the third interface (103) to connect to the fourth interface (104); closes valve one (7), and opens valve two (9) and valve three (11); then the controller controls the water-gas dual-purpose pump (5) to operate, and the water-gas dual-purpose pump (5) extracts air from the empty pipe (4) and pumps it into the temporary storage cylinder (6), and uses the air flow to drain the residual waste oil in the temporary storage cylinder (6) from the oil drain pipe (10) into the waste oil barrel (3); S2, extracting oil samples: the controller controls the four-way valve (1) to move to the second position, controls the first interface (101) to connect to the fourth interface (104); closes valve two (9) and valve three (11), and opens valve one (7); then the controller controls the water-gas dual-purpose pump (5) to move, and the water-gas dual-purpose pump (5) extracts insulating oil from the oil drain port of the transformer (2) through the first interface (101), and pumps the insulating oil into the temporary storage cylinder (6) through valve one (7) and the filter (8); S3, storing oil samples: the controller controls the four-way valve (1) to move to the first position, controls the third interface (103) to connect to the fourth interface (104); manually holds the sampling tube and places it at the outlet of the oil drain pipe (10); the controller controls valve 1 (7) and valve 3 (11) to open, and controls valve 2 (9) to close; then controls the water-gas dual-purpose pump (5) to operate, extracts gas from the empty pipe (4) and pumps it into the temporary storage cylinder (6), and pumps the insulating oil from the oil drain pipe (10) into the sampling tube.

9. The transformer insulating oil sampling method according to claim 8, characterized in that: The method further comprises step S4: the controller controls the four-way valve (1) to move to the third position, controls the fourth interface (104) to connect to the second interface (102); places flushing liquid in the temporary storage tube (6); the controller controls valve two (9) and valve three (11) to close, and controls valve one (7) to open; and then controls the water-gas dual-purpose pump (5) to move, pumps the flushing liquid in the temporary storage tube (6) into the four-way valve (1), and then pumps it into the waste oil barrel (3), so as to backwash the temporary storage tube (6) and the four-way valve (1).

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