Transformer cooler and online replacement method therefor, and rail vehicle

Abstract

The present invention provides a transformer cooler and an online replacement method therefor, and a rail vehicle. In the transformer cooler, a liquid inlet of the cooler is detachably connected to one end of a first valve, and a liquid outlet of the cooler is detachably connected to one end of a second valve; the other end of the first valve and the other end of the second valve are respectively used for being communicated with a coolant outlet and a coolant inlet of a transformer tank; the cooler is provided with a first gas discharge connector used for being communicated with the external atmosphere, a second gas discharge connector used for being connected to a vacuumizing device, and a liquid injection / discharge connector used for being connected to a liquid injection device or discharging liquid in the cooler; the first gas discharge connector, the second gas discharge connector, and the liquid injection / discharge connector are all communicated with an inner cavity of the cooler, and all have a closed state in which corresponding openings are sealed; and the first gas discharge connector and the second gas discharge connector are mounted on the upper portion of the cooler, and the liquid injection / discharge connector is mounted on the lower portion of the cooler.

Description

Cooler for transformer and online replacement method thereof, and rail vehicle TECHNICAL FIELD

[0001] The present application relates to a cooler for a transformer and an online replacement method thereof, and a rail vehicle, and belongs to the field of transformers of rail vehicles. BACKGROUND

[0002] The traction transformer of the motor train unit is installed on the train, converts the high-voltage electricity of the overhead line into various low-voltage electricity required by the traction system and auxiliary system, is a special voltage grade power transformer, needs to meet the requirement of drastic change of traction load, needs to suppress harmonic current and limit short-circuit current, so as to ensure the safe, stable and reliable operation of the electric transmission system of the train, is the power source of important functions such as traction, braking and communication of the high-speed motor train unit, and is the core and key component of the high-speed motor train unit.

[0003] The traction transformer of the motor train unit needs to meet the design requirements of light weight and small size due to the large line load, and needs to have high heat dissipation performance, so a dedicated cooler is arranged for heat dissipation. The existing traction transformer of the motor train unit is mainly an oil-immersed transformer. The high-temperature cooling medium in the transformer enters the cooler core through the oil pipe under the action of the oil pump, exchanges heat with the cooling air in the cooler core (heat exchange core), and then flows back to the oil tank of the traction transformer to exchange heat with various components in the oil tank, so as to realize the cooling of the traction transformer.

[0004] In the prior art as shown in FIG. 1, the cooler 10 is arranged on both sides of the transformer tank 20. The flow direction of the cooling liquid (such as transformer oil) is the transformer tank 20→the cooler 10 on one side of the transformer tank 20→the cooler 10 on the other side of the transformer tank 20, and then the cooling liquid returns to the transformer tank 20. The cooling liquid in the transformer tank 20 is cooled by heat exchange with the transformer coil and other components. The cooling liquid flowing out of the transformer tank 20 enters the cooler 10, exchanges heat with the cooling air in the cooler. The cooled cooling liquid returns to the transformer tank 20 to continue cooling the transformer coil and other components, so as to realize the cooling of the traction transformer.

[0005] In order to meet the requirements of miniaturization and light weight, the cooler 10 and the transformer tank 20 of the motor train unit traction transformer are usually designed in an integrated manner, as shown in FIG. 1. When the existing motor train unit traction transformer has a cooler oil leakage failure during line operation, the transformer as a whole (i.e. the integrated structure of the cooler 10 and the transformer tank 20) is usually removed from the train and returned to the factory. After replacing the new cooler, the transformer as a whole is vacuum filled with oil, and the outgoing inspection is completed. Then, the transformer is transported to the vehicle depot for installation and whole train debugging, and can be operated normally again. The cooler and the replacement method have problems of long replacement cycle, low efficiency, high cost, complex process, and occupation of many resources. SUMMARY

[0006] The problem to be solved by the present application is that the existing motor train unit for the transformer cooler failure needs to remove the whole structure including the transformer and the cooler from the train and return to the factory for maintenance, which has problems of long replacement cycle, low efficiency, high cost, complex process, and occupation of many resources. The present application provides a cooler for a transformer.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a cooler for a transformer, a liquid inlet of the cooler is detachably connected with one end of a first valve, a liquid outlet of the cooler is detachably connected with one end of a second valve, the other end of the first valve and the other end of the second valve are respectively used for communicating with a cooling liquid outlet of a transformer tank and a cooling liquid inlet.

[0008] The cooler is provided with a first gas discharge connector for communicating with the external atmosphere, a second gas discharge connector for connecting with a vacuum device, and a liquid injection / liquid discharge connector for connecting with a liquid injection device or discharging liquid in the cooler;

[0009] The first gas discharge connector, the second gas discharge connector, and the liquid injection / liquid discharge connector all communicate with the inner cavity of the cooler, and the opening of the first gas discharge connector, the opening of the second gas discharge connector, and the opening of the liquid injection / liquid discharge connector all have a closed state.

[0010] The first gas discharge connector and the second gas discharge connector are installed on the upper part of the cooler, and the liquid injection / liquid discharge connector is installed on the lower part of the cooler.

[0011] In the present application, by setting the first valve, the second valve, and detachably connecting the liquid inlet and the liquid outlet of the cooler with one end of the first valve and one end of the second valve respectively, when the cooler fails, the first valve and the second valve are closed, the cooling liquid passage between the cooler and the transformer tank is cut off, and the cooling liquid in the cooler and the cooling liquid in the transformer tank are independent of each other. By setting the liquid injection / liquid discharge joint, the cooling liquid in the failed cooler can be discharged outward without affecting the cooling liquid in the transformer tank after the cooling liquid passage is cut off. The failed cooler can be removed and replaced. By setting the second gas discharge joint and the liquid injection / liquid discharge joint, the cooler can be vacuumized when injecting cooling liquid, and the air in the cooler can be fully discharged when injecting oil, ensuring the safety of the transformer after the cooler and the transformer tank are connected again, and avoiding the problems of safety hazards caused by insufficient gas discharge and long oil injection period. By setting the first gas discharge joint, when the cooler has been injected with a high level of cooling liquid, which is not suitable for further vacuumization, the air in the cooler can be discharged into the external atmosphere through the first gas discharge joint. Considering that air tends to flow upward and cooling liquid tends to flow downward, the first gas discharge joint and the second gas discharge joint are installed on the upper part of the cooler, and the liquid injection / liquid discharge joint is installed on the lower part of the cooler, which is conducive to air discharge, cooling liquid discharge and injection.

[0012] Further, the cooler comprises a heat exchange core and a cooling liquid containing cavity arranged adjacent to the heat exchange core, the heat exchange core has at least one cooling liquid passage, and each cooling liquid passage is in communication with the cooling liquid containing cavity;

[0013] The liquid inlet and the liquid outlet of the cooler are located in the cooling liquid containing cavity;

[0014] The first gas discharge joint and the second gas discharge joint are installed on the upper part of the cooling liquid containing cavity, and the liquid injection / liquid discharge joint is installed on the lower part of the cooling liquid containing cavity;

[0015] The first gas discharge joint, the second gas discharge joint and the liquid injection / liquid discharge joint are in communication with the inner cavity of the cooling liquid containing cavity.

[0016] Through the above arrangement, the cooling liquid entering the cooler from the liquid inlet passes through the cooling liquid containing cavity into the cooling liquid passage of the heat exchange core, the cooling liquid is cooled (for example, the cooling liquid in the cooling liquid passage is cooled by the fan and the external air), and then returns to the cooling liquid containing cavity through the outlet of the cooling liquid passage. When there are multiple (≥2) cooling liquid passages, the cooling liquid containing cavity also plays a role in mixing the liquid flowing out of each cooling liquid passage to avoid the temperature of the liquid flowing out of the cooling liquid containing cavity changing sharply.

[0017] In the preferred technical solution, the first air outlet joint and the second air outlet joint are arranged on the top surface of the cooling liquid containing cavity; and the liquid injection / liquid discharge joint is arranged on the bottom surface of the cooling liquid containing cavity.

[0018] Through the above arrangement, the air is discharged, and the cooling liquid is discharged and injected.

[0019] Further, the heat exchange core is provided with cooling liquid containing cavities on both sides and in communication with the cooling liquid channels of the heat exchange core, and the cooling liquid containing cavities on both sides of the heat exchange core are respectively a first cooling liquid containing cavity and a second cooling liquid containing cavity; and the liquid inlet and the liquid outlet of the cooler are arranged in the first cooling liquid containing cavity.

[0020] Through the above arrangement, the cooling liquid entering one of the cooling liquid containing cavities passes through the heat exchange core to reach the other cooling liquid containing cavity, and then passes through the heat exchange core again to return to the one cooling liquid containing cavity, so that the heat dissipation effect of the cooling liquid is better.

[0021] In the preferred technical solution, the second air outlet joint and the liquid injection / liquid discharge joint are arranged in different cooling liquid containing cavities.

[0022] Through the above arrangement, the inlet of the liquid injection (i.e. the liquid injection / liquid discharge joint) and the outlet of the vacuum extraction (i.e. the second air outlet joint) are located in different cavities, so that the vacuum extraction effect is better.

[0023] In the preferred technical solution, each cooling liquid containing cavity is provided with a first air outlet joint.

[0024] Through the above arrangement, the air in each cooling liquid containing cavity can be effectively discharged outward.

[0025] In the preferred technical solution, a partition is arranged in the first cooling liquid containing cavity, the partition divides the inner cavity of the first cooling liquid containing cavity into a first cavity and a second cavity which are independent of each other, the liquid inlet of the cooler is arranged towards the first cavity, the liquid outlet of the cooler is arranged towards the second cavity, and the liquid inlet of the cooler is in communication with the liquid outlet of the cooler in sequence through the first cavity, a cooling liquid channel of the heat exchange core arranged towards the first cavity, the second cooling liquid containing cavity, a cooling liquid channel of the heat exchange core arranged towards the second cavity, and the second cavity.

[0026] The applicant finds that when the cooling liquid containing cavities are arranged on both sides of the heat exchange core and the inlet and outlet of the cooler are arranged in the first cooling liquid containing cavity, the cooling liquid channel from the first cooling liquid containing cavity to the second cooling liquid containing cavity and the cooling liquid channel from the second cooling liquid containing cavity to the first cooling liquid containing cavity need to be formed in the heat exchange core so that the cooling liquid passes through the heat exchange core twice to achieve a better heat dissipation effect. However, in the prior art, after the liquid injection is completed, the liquid in the cooler does not form a circulating flow. When the first valve and the second valve are opened, the liquid entering from the inlet tends to select the path with smaller pressure, i.e. the flow path of inlet→first cooling liquid containing cavity→outlet, and cannot pass through the heat exchange core to enter the second cooling liquid containing cavity, so that the heat dissipation effect of the liquid is poor and the advantage of arranging the cooling liquid containing cavities on both sides of the heat exchange core cannot be effectively exerted.

[0027] Through the above preferred technical scheme, when the oil circuit of the transformer tank and the cooler is circulated as a whole, the liquid entering the first cooling liquid containing cavity from the inlet can only flow through the first cavity to the cooling liquid channel of the heat exchange core, so that the liquid flow path of inlet, first cavity, the cooling liquid channel of the heat exchange core arranged towards the first cavity, second cooling liquid containing cavity, the cooling liquid channel of the heat exchange core arranged towards the second cavity, second cavity and outlet can be formed, and a better heat dissipation effect of the liquid can be achieved. Moreover, through the above arrangement, when the liquid injection / drainage connector is used to inject liquid, the liquid flow path of liquid injection / drainage connector, first cavity, the cooling liquid channel of the heat exchange core arranged towards the first cavity, second cooling liquid containing cavity, the cooling liquid channel of the heat exchange core arranged towards the second cavity and second cavity can be formed, and the cooling liquid injection of the first cavity and the second cavity can be completed at one time.

[0028] In a more preferred technical scheme, the cooling liquid channel includes at least one first cooling liquid channel arranged towards the first cavity and at least one second cooling liquid channel arranged towards the second cavity, each first cooling liquid channel and each second cooling liquid channel communicates the first cooling liquid containing cavity and the second cooling liquid containing cavity; the cooler further includes a channel valve for opening / closing each second cooling liquid channel; the liquid injection / drainage connector is arranged in the first cooling liquid containing cavity, and the second gas discharge connector is arranged in the second cooling liquid containing cavity.

[0029] In the application, by arranging the passage valve in the second cooling liquid passage, each second cooling liquid passage can be closed during the initial liquid injection process, i.e. the liquid entering the first cooling liquid containing cavity only passes through each first cooling liquid passage to enter the second cooling liquid containing cavity, when the liquid in the second cooling liquid containing cavity reaches a certain height, each second cooling liquid passage is opened, and the oil injection continues, at this time, the liquid in the second cooling liquid containing cavity enters the second cavity of the first cooling liquid containing cavity through each second cooling liquid passage, and the liquid level in the second cooling liquid containing cavity also drops, thereby realizing the flow path of the first cavity→ each first cooling liquid passage→ the second cooling liquid containing cavity→ each second cooling liquid passage→ the second cavity. Through the above arrangement, when the first valve and the second valve are subsequently opened, a certain flow circulation has been formed in the cooler, thereby facilitating the oil path connection of the transformer tank and the cooler to form an overall oil path circulation.

[0030] Further, the inner cavity top surface of the heat exchange core, the inner cavity top surface of the cooling liquid containing cavity provided with the first gas discharge connector, and the inner cavity top surface of the first gas discharge connector are sequentially increased in height.

[0031] The inner cavity bottom surface of the heat exchange core, the inner cavity bottom surface of the cooling liquid containing cavity provided with the liquid injection / discharge connector, and the inner cavity bottom surface of the liquid injection / discharge connector are sequentially decreased in height.

[0032] Since air tends to flow to a higher position and liquid tends to flow to a lower position, through the above arrangement, the air in the inner cavity can be discharged as completely as possible, and the cooling liquid can be discharged completely, thereby avoiding the phenomenon of affecting the normal operation of the transformer due to local high point gas collection and liquid residue.

[0033] Further, the cooler further comprises a liquid level height sensor for measuring the liquid level height in the cooling liquid containing cavity, and the output end of the liquid level height sensor and the control end of the vacuumizing device are electrically connected with the controller.

[0034] The controller is configured to close the vacuumizing device when the output end of the liquid level height sensor outputs the first set height (i.e. when the liquid level height in the inner cavity of the cooler reaches the first set height). Through the above arrangement, when the liquid level reaches the preset value, the vacuumizing device can be closed, thereby avoiding the vacuumizing device from discharging the cooling liquid.

[0035] Further, the first bleed joint has a first screw sleeve installed on the cooler, and a first connecting piece; the first screw sleeve inner cavity is communicated with the cooler inner cavity; the first connecting piece is screwed with the first screw sleeve inner thread, thereby closing the first screw sleeve opening or communicating the first screw sleeve inner cavity with the external atmosphere. The first connecting piece has a head for closing the first screw sleeve opening, and an outer threaded rod part screwed with the first screw sleeve inner thread, and the outer threaded rod part is provided with a first air flow channel for communicating the first screw sleeve inner cavity with the external atmosphere when the head is not contacted with the first screw sleeve.

[0036] The second bleed joint has a second screw sleeve installed on the cooler, and a second connecting piece for connecting with the vacuumizing device; the second screw sleeve inner cavity is communicated with the cooler inner cavity; the second connecting piece is screwed with the second screw sleeve inner thread.

[0037] The liquid injection / liquid discharge joint has a third screw sleeve installed on the cooler, and a third connecting piece for connecting with the liquid injection device or for closing the third screw sleeve opening; the third screw sleeve inner cavity is communicated with the cooler inner cavity; the third connecting piece is screwed with the third screw sleeve inner thread.

[0038] Through the above arrangement, the first connecting piece is screwed with the first screw sleeve inner thread, so that when being screwed, the first screw sleeve opening is closed, when the first connecting piece is screwed to have a gap between the head and the first screw sleeve, the first air flow channel can communicate the first screw sleeve inner cavity with the external atmosphere. When the first connecting piece is screwed to have a close contact between the head and the first screw sleeve, the first screw sleeve opening is closed, so that the first screw sleeve inner cavity is not communicated with the external atmosphere.

[0039] In the preferred technical solution, at least one of the first screw sleeve, the second screw sleeve and the third screw sleeve comprises an aluminum sleeve installed on the cooler, and a steel sleeve fixedly installed on the inner side of the aluminum sleeve, the inner side of the steel sleeve forms an inner thread matched with the corresponding connecting piece (the first connecting piece, or the second connecting piece, or the third connecting piece); the cooler is made of aluminum, and the corresponding connecting piece is made of steel.

[0040] By arranging the aluminum sleeve and the steel sleeve fixedly installed on the inner side of the aluminum sleeve, the aluminum sleeve can be matched with the cooler of the same material, and the steel sleeve can be matched with the corresponding connecting piece, so that the phenomenon that the bolt is easily broken when being screwed in the traditional steel screw and aluminum screw seat can be avoided.

[0041] In the preferred technical solution, the second connecting piece is a quick connector.

[0042] In a preferred technical solution, the third connecting member comprises a fastener for closing the third threaded sleeve opening, and a quick connector for connecting with the liquid injection device, and the third threaded sleeve inner thread is switchably connected with the quick connector and the fastener; more preferably, the fastener has a fastener head for closing the third threaded sleeve opening, and a fastener outer thread rod for cooperating with the third threaded sleeve inner thread, and a second air flow channel is formed on the fastener outer thread rod for connecting the third threaded sleeve inner cavity with the external atmosphere when the fastener head is not in contact with the third threaded sleeve.

[0043] Through the above arrangement, when the fastener is screwed to have a gap between the fastener head and the third threaded sleeve, the second air flow channel can connect the third threaded sleeve inner cavity with the external atmosphere, so as to discharge the cooling liquid in the cooler inner cavity. When the fastener is screwed to have the fastener head in close contact with the third threaded sleeve, the third threaded sleeve opening is closed, so that the third threaded sleeve inner cavity is not connected with the external atmosphere, and the cooling liquid cannot flow out.

[0044] According to the same inventive concept, the application further provides a railway vehicle comprising the above-described cooler, and the transformer is a traction transformer of the railway vehicle.

[0045] According to the same inventive concept, the application further provides an online replacement method of a cooler, characterized in that the cooler is the above-described cooler.

[0046] The online replacement method comprises the following steps:

[0047] (S1) closing the first valve and the second valve;

[0048] (S2) disconnecting the cooler to be replaced from the first valve and the second valve, and dismounting the cooler to be replaced;

[0049] (S3) connecting the liquid inlet of the replaced cooler with one end of the first valve, and connecting the liquid outlet of the replaced cooler with one end of the second valve;

[0050] (S4) connecting the second air outlet connector with the vacuum pumping device, and keeping the first air outlet connector and the liquid injection / liquid discharge connector in a closed state, and starting the vacuum pumping device;

[0051] (S5) when the vacuum degree of the cooler inner cavity reaches a set vacuum degree, connecting the liquid injection device with the liquid injection / liquid discharge connector, and injecting liquid into the cooler at a first liquid injection speed;

[0052] (S6) when the liquid surface height of the cooler inner cavity reaches a first set height, stopping the vacuum pumping device, and changing the second air outlet connector from an open state to a closed state;

[0053] (S7) injecting liquid into the cooler at a second liquid injection speed while changing the first gas exhaust joint from the closed state to the open state until the liquid injection is completed, wherein the second liquid injection speed is less than the first liquid injection speed;

[0054] (S8) changing the first gas exhaust joint from the open state to the closed state after the liquid injection is completed;

[0055] (S9) opening the first valve and the second valve.

[0056] By the above technical solution, the first valve and the second valve are closed, the communication between the inner cavity of the cooler and the inner cavity of the transformer tank is cut off, the first gas exhaust joint and the liquid injection / liquid exhaust joint are opened, the liquid in the cooler is exhausted, and then the cooler is replaced. After the cooler is replaced, vacuumizing is performed by the vacuumizing device, and then oil is injected. When the liquid level in the inner cavity of the cooler reaches the first set height, if vacuumizing is continued, the cooling liquid may be exhausted, therefore the vacuumizing device is closed, the first gas exhaust joint is opened, the air in the inner cavity is exhausted to the outside atmosphere through the first gas exhaust joint, and then liquid injection is continued until the liquid injection is completed. For example, if the cooling liquid flows out of the first gas exhaust joint, it is judged that the liquid injection is completed. When the liquid level is high, the liquid is injected at a lower second liquid injection speed to avoid too fast liquid injection. Preferably, between the operation of closing the first valve and the second valve and the operation of disassembling the cooler to be replaced, there further comprises: opening the first gas exhaust joint and the liquid injection / liquid exhaust joint to exhaust the liquid in the cooler.

[0057] Further, the cooler comprises a heat exchange core and a cooling liquid containing cavity arranged adjacent to the heat exchange core, the heat exchange core has at least one cooling liquid passage, each cooling liquid passage is in communication with the cooling liquid containing cavity; the liquid inlet and the liquid outlet of the cooler are located on the cooling liquid containing cavity; the height of the inner cavity top surface of the heat exchange core, the inner cavity top surface of the cooling liquid containing cavity where the first gas exhaust joint is arranged and the inner cavity top surface of the first gas exhaust joint increases in sequence;

[0058] The first gas exhaust joint has a first screw sleeve mounted on the cooler and a first connecting piece; the inner cavity of the first screw sleeve is in communication with the inner cavity of the cooler; the first connecting piece is threadedly matched with the first screw sleeve to close the opening of the first screw sleeve or to communicate the inner cavity of the first screw sleeve with the outside atmosphere; the first connecting piece has a head portion for closing the opening of the first screw sleeve and an outer threaded rod portion threadedly matched with the first screw sleeve, and the outer threaded rod portion is provided with a first air flow passage for communicating the inner cavity of the first screw sleeve with the outside atmosphere when the head portion is not in contact with the first screw sleeve;

[0059] The first air flow passage has a passage segment opening formed on the outer wall of the outer threaded rod portion;

[0060] The step (S7) of changing the first gas exhaust joint opening from the closed state to the open state is specifically:

[0061] (S71) when the length of the part in the first projection that does not coincide with the second projection accounts for a preset proportion p1 of the length of the first projection, stop screwing the first connecting piece until the stop time reaches a preset time t1;

[0062] (S72) when the stop time reaches the preset time t1, continue to screw the first connecting piece until the length of the part in the first projection that does not coincide with the second projection accounts for 1 of the length of the first projection;

[0063] wherein p1∈[1 / 4, 1 / 2]; the first projection is the projection of the channel segment opening on the outer threaded rod axis, and the second projection is the projection of the first sleeve on the outer threaded rod axis.

[0064] The applicant found during research that when the first gas exhaust joint is used for exhaust, the air content in the cooler may not be high, and if the first gas exhaust joint opening is directly set to the maximum, the cooling liquid may flow out of the first gas exhaust joint in a short time, causing certain pollution to the equipment. Moreover, the liquid may still mix with some air, and if the exhaust through the first gas exhaust joint is too fast, the air mixed in the liquid may flow out before the cooling liquid flows out of the first gas exhaust joint, so that the first gas exhaust joint can only be closed and the air mixed in the liquid cannot be fully exhausted. Through the above technical solution, when the length of the part in the first projection that does not coincide with the second projection accounts for a preset proportion p1 (p1 is in the range of [1 / 4, 1 / 2]) of the length of the first projection, stop screwing the first connecting piece until the stop time reaches a preset time t1. Within this preset time t1, a certain time can be left for the air mixed in the oil to flow to the top surface of the inner cavity of the first gas exhaust joint at the highest height, so that the exhaust is more complete.

[0065] In the preferred technical solution, when the proportion reaches the preset proportion p1 (i.e. when the air is exhausted), the channel segment opening is located at the top end of the first air flow channel. Through the above setting, the air flow of the first air flow channel flows out through the channel segment opening located at the top end upward, thereby facilitating the exhaust of the air flow.

[0066] In the preferred technical solution, the cooler comprises a heat exchange core, a cooling liquid containing cavity arranged adjacent to the heat exchange core, the heat exchange core having at least one cooling liquid passage; a first gas discharge joint and a second gas discharge joint are installed on the upper portion of the cooling liquid containing cavity, and a liquid injection / discharge joint is installed on the lower portion of the cooling liquid containing cavity; the first gas discharge joint, the second gas discharge joint and the liquid injection / discharge joint are all in communication with the inner cavity of the cooling liquid containing cavity; the heat exchange core is provided with the cooling liquid containing cavities on both sides and in communication with the cooling liquid passages of the heat exchange core; the second gas discharge joint and the liquid injection / discharge joint are arranged in different cooling liquid containing cavities;

[0067] The cooling liquid containing cavities on both sides of the heat exchange core are respectively a first cooling liquid containing cavity and a second cooling liquid containing cavity; the liquid injection / discharge joint is installed on the lower portion of the first cooling liquid containing cavity, and the second gas discharge joint is installed on the upper portion of the second cooling liquid containing cavity; the liquid inlet and the liquid outlet of the cooler are arranged in the first cooling liquid containing cavity;

[0068] A partition plate is arranged in the first cooling liquid containing cavity, and the partition plate divides the inner cavity of the first cooling liquid containing cavity into a first cavity and a second cavity which are independent of each other;

[0069] The liquid inlet of the cooler is arranged towards the first cavity, the liquid outlet of the cooler is arranged towards the second cavity, and the liquid inlet of the cooler is in communication with the liquid outlet of the cooler in sequence through the first cavity, a cooling liquid passage of the heat exchange core arranged towards the first cavity, the second cooling liquid containing cavity, a cooling liquid passage of the heat exchange core arranged towards the second cavity and the second cavity;

[0070] The cooling liquid passage comprises at least one first cooling liquid passage arranged towards the first cavity and at least one second cooling liquid passage arranged towards the second cavity, and each first cooling liquid passage and each second cooling liquid passage are in communication with the first cooling liquid containing cavity and the second cooling liquid containing cavity;

[0071] In the process of starting the vacuumizing device until the vacuum degree of the inner cavity of the cooler reaches the set vacuum degree, each first cooling liquid passage and each second cooling liquid passage are in an open state;

[0072] In the step (S5), before the cooler is filled with liquid at a first liquid filling speed, each second cooling liquid passage is changed from an open state to a closed state; when the liquid level in the second cooling liquid containing cavity reaches a second set height, each second cooling liquid passage is changed from the closed state to the open state; the second set height is higher than the height at which each first cooling liquid passage is located and higher than the height at which each second cooling liquid passage is located;

[0073] The liquid level in the first cooling liquid containing cavity and the liquid level in the second cooling liquid containing cavity reach the first set height in the step (S6), and the first set height is not lower than the second set height.

[0074] Preferably, the first cavity is below the second cavity.

[0075] Preferably, the partition plate extends in the height direction of the first cooling liquid containing cavity, and the first cavity and the second cavity are located on two sides of the partition plate. The second set height can be the same as the first set height, or the size relationship between the two can be set according to actual needs.

[0076] In the present application, the second cooling liquid passages are closed and only the first cooling liquid passages are opened when the vacuumizing and liquid injection operation is performed in the step (S5). Since the second gas discharge joint and the liquid injection / discharge joint are arranged in different cooling liquid containing cavities, the cooling liquid in the first cavity of the first cooling liquid containing cavity entering from the liquid injection / discharge joint under the negative pressure of the vacuumizing device enters the second cooling liquid containing cavity through the first cooling liquid passage. When the liquid level in the second cooling liquid containing cavity reaches the second set height, the first cooling liquid passages are opened, and at this time, the liquid in the second cooling liquid containing cavity enters the second cavity of the first cooling liquid containing cavity through the second cooling liquid passages, and the liquid level in the second cooling liquid containing cavity also drops. The vacuumizing and liquid injection operation is continuously performed until the liquid level in the second cooling liquid containing cavity reaches the first set height, at which time the vacuumizing device is closed to avoid the cooling liquid being sucked in. After the vacuumizing device is closed, the operation in the steps (S6) and (S7) is performed, that is, the second gas discharge joint is closed, the first gas discharge joint is opened, and the liquid injection is continuously performed at the second liquid injection speed, at which time the flow path of the liquid is still the first cavity→the first cooling liquid passages→the second cooling liquid containing cavity→the second cooling liquid passages→the second cavity. Through the above arrangement, when the first valve and the second valve are subsequently opened, a certain flow circulation has been formed in the cooler, so that after the oil circuit of the transformer tank and the cooler is connected, the overall oil circuit circulation is formed.

[0077] The application has the advantages and positive effects that the online replaceable cooler can quickly and safely realize online replacement of the cooler. Compared with the prior art that the transformer is taken off as a whole for maintenance due to the failure of the cooler, the application can shorten the replacement period, improve the replacement efficiency, reduce the transportation, replacement, debugging and other costs, and reduce the occupation of the whole vehicle and the depot resources. Compared with the traditional normal pressure oil injection mode, the application can fully discharge the air in the cooler, ensure the safety of the transformer, avoid the safety hazards and long period caused by insufficient air discharge, and does not need to lift the oil injection equipment to a high height, thereby saving the operation space, reducing the requirements on the operation environment, and increasing the operability on site. The application has the characteristics of short replacement period, high efficiency, low cost and high safety. BRIEF DESCRIPTION OF DRAWINGS

[0078] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0079] Fig. 1 is a top view of the connection structure of the transformer tank and the cooler in the prior art;

[0080] Fig. 2 is a top view of the connection structure of the cooler and the transformer tank in the embodiment 1 of the present application;

[0081] Fig. 3 is a front view of the connection of the cooler and the first valve and the second valve in Fig. 2;

[0082] Fig. 4 is a front view of the connection of the cooler and the vacuumizing device and the liquid injection equipment in Fig. 3;

[0083] Fig. 5 is a top view of the connection of the cooler and the first valve and the second valve in Fig. 2;

[0084] Fig. 6 is a side view of the cooler from the direction A in Fig. 3;

[0085] Fig. 7 is a side view of the cooler from the direction B in Fig. 3;

[0086] Fig. 8 is a sectional view of the first air release joint connected to the accommodating cavity of the cooler in Fig. 2, wherein the sectional line of the head of the fastener is not shown;

[0087] Fig. 8(a) is a schematic view of the first projection and the second projection on the axis of the outer threaded rod part when the first connecting piece closes the first screw sleeve opening in Fig. 8;

[0088] Fig. 8(b) is a schematic view of the first projection, the second projection on the outer threaded rod axis when the first connecting member is moved to a position where the length of the first projection that does not coincide with the second projection in the first projection is 1 / 3 of the length of the first projection in Fig. 8;

[0089] Fig. 8(c) is a C-C sectional view of the first connecting member in Fig. 8;

[0090] Fig. 9 is a sectional view of the second gas outlet joint connected to the cooler accommodating cavity in Fig. 2;

[0091] Fig. 10 is a sectional view of the liquid injection / liquid discharge joint connected to the cooler accommodating cavity in Fig. 2;

[0092] Fig. 11 is a front view of the cooler connected with the first valve and the second valve in Embodiment 2 of the present application, wherein the arrangement positions of the first gas outlet joint, the second gas outlet joint and the liquid injection / liquid discharge joint are shown;

[0093] Fig. 12 is a front view of the cooler connected with the first valve and the second valve in Embodiment 3 of the present application;

[0094] Fig. 13 is a rear view of the cooler connected with the first valve and the second valve in Embodiment 3 of the present application;

[0095] Fig. 14 is a top view of the cooler connected with the first valve and the second valve in Embodiment 3 of the present application;

[0096] Fig. 15 is a D-D sectional view of Fig. 14;

[0097] Fig. 16 is a front view of the cooler connected with the first valve and the second valve in Embodiment 4 of the present application;

[0098] Fig. 17 is an E-E sectional view of Fig. 16.

[0099] In the above drawings: cooler 10, transformer tank 20, first valve 30, second valve 40, vacuum pump 50, liquid injection device 60, first gas outlet 1, second gas outlet 2, liquid injection / liquid discharge joint 3, heat exchange core 4, first cooling liquid passage 43, second cooling liquid passage 44, partition plate 510, cooling liquid containing cavity 5, first cooling liquid containing cavity 51, second cooling liquid containing cavity 52, first cavity 511, second cavity 512, top surface of inner cavity of heat exchange core 4A, bottom surface of inner cavity of heat exchange core 4B, top surface of inner cavity of cooling liquid containing cavity 5A, bottom surface of inner cavity of cooling liquid containing cavity 5B, top surface of inner cavity of first gas outlet 1A, top surface of inner cavity of second gas outlet 2A, bottom surface of inner cavity of liquid injection / liquid discharge joint 3B, first aluminum sleeve 11, first steel sleeve 12, first connecting piece 13, head 131, externally threaded rod portion 132, first gas flow passage 133, first sealing ring 14, first screw sleeve 15, second aluminum sleeve 21, second steel sleeve 22, second connecting piece 23, second sealing ring 24, protective sleeve 25, third aluminum sleeve 31, third steel sleeve 32, fastener 33, head of fastener 331, externally threaded rod portion of fastener 332, third sealing ring 34, first pipeline 101, second pipeline 102, third pipeline 201, fourth pipeline 202, axis of externally threaded rod portion L1, first projection R-13, second projection R-15. DETAILED DESCRIPTION

[0100] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment 1

[0101] As shown in FIGS. 2-10, the present application provides a cooler for a transformer. The liquid inlet of the cooler 10 is detachably connected to one end of the first valve 30, and the liquid outlet of the cooler 10 is detachably connected to one end of the second valve 40. The other end of the first valve 30 and the other end of the second valve 40 are respectively used to communicate with the cooling liquid outlet and the cooling liquid inlet of the transformer tank 20.

[0102] The cooler 10 is provided with a first gas outlet 1 for communicating with the external atmosphere, a second gas outlet 2 for connecting with the vacuum pump 50, and a liquid injection / liquid discharge joint 3 for connecting with the liquid injection device 60 or discharging the liquid in the cooler.

[0103] The first gas exhaust joint 1, the second gas exhaust joint 2 and the liquid injection / liquid discharge joint 3 are all communicated with the inner cavity of the cooler 10, and the opening of the first gas exhaust joint 1, the opening of the second gas exhaust joint 2 and the opening of the liquid injection / liquid discharge joint 3 all have a closed state.

[0104] The first gas exhaust joint 1 and the second gas exhaust joint 2 are installed on the upper part of the cooler, and the liquid injection / liquid discharge joint 3 is installed on the lower part of the cooler 10.

[0105] The cooling oil for the transformer mainly functions as heat dissipation and insulation, and if there is gas in the oil passage of the transformer, the pressure resistance of the oil will be reduced, and discharge phenomenon may occur, which brings great safety hazard to the operation of the transformer. Therefore, the gas content in the transformer oil can be well controlled by the method of vacuumizing and oiling at the same time.

[0106] The cooler 10 comprises a heat exchange core 4, and the heat exchange core 4 has at least one cooling liquid passage, each of which is communicated with a cooling liquid containing cavity 5; the liquid inlet and the liquid outlet of the cooler 10 are both located on the cooling liquid containing cavity 5.

[0107] The first gas exhaust joint 1 and the second gas exhaust joint 2 are installed on the upper part of the cooling liquid containing cavity 5 (i.e. the position where the side part of the cooling liquid containing cavity 5 is higher than half of the height dimension of the cooling liquid containing cavity 5, or the top of the cooling liquid containing cavity 5), and the liquid injection / liquid discharge joint 3 is installed on the lower part of the cooling liquid containing cavity 5 (i.e. the position where the side part of the cooling liquid containing cavity 5 is lower than half of the height dimension of the cooling liquid containing cavity 5, or the bottom of the cooling liquid containing cavity 5).

[0108] The first gas exhaust joint 1, the second gas exhaust joint 2 and the liquid injection / liquid discharge joint 3 are all communicated with the inner cavity of the cooling liquid containing cavity 5.

[0109] The cooler further comprises a liquid level sensor (not shown in the figure) for measuring the liquid level height in the cooling liquid containing cavity 5, and the output end of the liquid level sensor and the control end of the vacuumizing device 50 are both electrically connected with the controller. The controller can adopt a DSP, a single-chip microcomputer or a PLC controller.

[0110] As shown in Fig. 8, the first gas exhaust joint 1 has a first screw sleeve and a first connecting piece 13 installed on the cooler; the inner cavity of the first screw sleeve is communicated with the inner cavity of the cooler 10; and the first connecting piece 13 is threadedly matched with the first screw sleeve, so as to close the opening of the first screw sleeve or to communicate the inner cavity of the first screw sleeve with the external atmosphere. When the first gas exhaust joint 1 is installed on the side part of the cooling liquid containing cavity 5, the axis of the first screw sleeve is perpendicular to the height direction of the cooler; and when the first gas exhaust joint 1 is installed on the top of the cooling liquid containing cavity 5, the axis of the first screw sleeve is parallel to the height direction of the cooler.

[0111] As shown in Fig. 9, the second gas release joint 2 has a second screw sleeve installed on the cooler, a second connecting piece 23 for connecting with the vacuumizing device 50; the inner cavity of the second screw sleeve communicates with the inner cavity of the cooler 10; the second connecting piece 23 is threadedly matched with the inner thread of the second screw sleeve. When the second gas release joint 2 is installed on the side of the cooling liquid containing cavity 5, the axis of the second screw sleeve is perpendicular to the height direction of the cooler; when the second gas release joint 2 is installed on the top of the cooling liquid containing cavity 5, the axis of the second screw sleeve is parallel to the height direction of the cooler.

[0112] As shown in Fig. 10, the liquid injection / liquid discharge joint 3 has a third screw sleeve installed on the cooler, a third connecting piece for connecting with the liquid injection device or for closing the opening of the third screw sleeve; the inner cavity of the third screw sleeve communicates with the inner cavity of the cooler 10; the third connecting piece is threadedly matched with the inner thread of the third screw sleeve. When the third gas release joint 3 is installed on the side of the cooling liquid containing cavity 5, the axis of the third screw sleeve is perpendicular to the height direction of the cooler; when the third gas release joint 3 is installed on the bottom of the cooling liquid containing cavity 5, the axis of the third screw sleeve is parallel to the height direction of the cooler.

[0113] In the preferred technical solution, the first screw sleeve 15 comprises a first aluminum sleeve 11 installed on the cooler, a first steel sleeve 12 fixedly installed on the inner side of the first aluminum sleeve 11, the first steel sleeve 12 having inner thread for matching with the outer thread rod portion 132; the cooler 10 is made of aluminum, and the first connecting piece 13 is made of steel.

[0114] In the preferred technical solution, the second screw sleeve comprises a second aluminum sleeve 21 installed on the cooler, a second steel sleeve 22 fixedly installed on the inner side of the second aluminum sleeve 21, the second steel sleeve 22 having inner thread for matching with the second connecting piece 23; the cooler 10 is made of aluminum, and the second connecting piece 23 is made of steel.

[0115] In the preferred technical solution, the third screw sleeve comprises a third aluminum sleeve 31 installed on the cooler, a third steel sleeve 32 fixedly installed on the inner side of the third aluminum sleeve 31, the third steel sleeve 32 having inner thread for matching with the third connecting piece; the cooler 10 is made of aluminum, and the third connecting piece is made of steel.

[0116] Preferably, the first connecting piece 13 has a head portion 131 for closing the opening of the first screw sleeve, an outer thread rod portion 132 for threadedly matching with the inner thread of the first screw sleeve, and a first air flow passage 133 formed on the outer thread rod portion 132 for communicating the inner cavity of the first screw sleeve with the external atmosphere when the head portion 131 is not in contact with the first screw sleeve. The first connecting piece 13 can be a screw or a bolt.

[0117] Preferably, the second connecting piece can adopt a quick connector.

[0118] Preferably, the third connecting piece comprises a fastener 33 for closing the third threaded sleeve opening, a quick connector for connecting with the liquid injection device, and the third threaded sleeve inner thread is switchably connected with the quick connector and the fastener 33. When liquid injection or drainage is needed, the third threaded sleeve inner thread is connected with the quick connector; when the liquid injection or drainage is completed and the opening needs to be closed, the third threaded sleeve inner thread is connected with the fastener 33. More preferably, the fastener 33 has a fastener head 331 for closing the third threaded sleeve opening, and a fastener outer threaded rod 332 for cooperating with the third threaded sleeve inner thread, and a second air flow channel is formed on the fastener outer threaded rod 332 for connecting the third threaded sleeve inner cavity with the external atmosphere when the fastener head 331 is not in contact with the third threaded sleeve. The fastener 33 can be a screw or a bolt. The second air flow channel can have a similar structure as the first air flow channel. When the second air flow channel is provided, the fastener 33 can be loosened to achieve drainage when drainage is needed.

[0119] According to the same inventive concept, the application also provides a rail vehicle, characterized in that it comprises the above-mentioned cooler, and the transformer is a traction transformer of the rail vehicle.

[0120] As shown in FIG. 2, the liquid inlet and the liquid outlet of the cooler are respectively connected with the first pipeline 101 and the second pipeline 102, and the first pipeline 101 and the second pipeline 102 are respectively detachably connected with one end of the first valve 30 and one end of the second valve 40. The other end of the first valve 30 is connected with the cooling liquid outlet of the transformer box 20 through the third pipeline 201, and the other end of the second valve 40 is connected with the cooling liquid inlet of the transformer box 20 through the fourth pipeline 202. In FIG. 2, the arrows represent the flow direction of the cooling liquid. The positions of the first pipeline 101, the second pipeline 102, the first valve 30 and the second valve 40 can be adjusted according to actual conditions.

[0121] The online replaceable cooler provided by the application is suitable for the field of rail transit traction transformers, and can be replaced online without disassembling the traction transformer, thereby greatly shortening the replacement period, reducing transportation, replacement, debugging and other costs, and reducing the occupation of whole vehicle and depot resources. At the same time, the cooler can be vacuum filled with oil separately, thereby avoiding the risk of gas existing in the cooler and entering the transformer, and having the characteristics of short replacement period, high efficiency, low cost and high safety.

[0122] The application is further described below. As shown in Figs. 2-5, the application provides an online replaceable cooler suitable for the field of transformers, comprising a first gas outlet 1, a second gas outlet 2, a liquid injection / liquid discharge joint 3, a heat exchange core 4, a cooling liquid containing cavity 5 (also referred to as a cooling liquid collecting box), a first valve 30, a first pipeline 101, a second valve 40, a second pipeline 102, the first gas outlet 1 and the second gas outlet 2 being located at the upper part of the cooling liquid containing cavity 5, and the liquid injection / liquid discharge joint 3 being located at the lower part of the cooling liquid containing cavity 5. The first valve 30 and the second valve 40 are connected to the cooling liquid containing cavity 5 through the first pipeline 101 and the second pipeline 102 respectively, and the cooler 10 is connected to the transformer tank 20 through the first valve 30 and the second valve 40, as shown in Figs. 2 and 3.

[0123] As shown in Figs. 6 and 7, the height relationship of the inner cavity top surface 4A of the heat exchange core, the inner cavity top surface 5A of the cooling liquid containing cavity, the inner cavity top surface 1A of the first gas outlet, and the inner cavity top surface 2A of the second gas outlet is that the inner cavity top surface 1A and the inner cavity top surface 2A are both higher than the inner cavity top surface 5A, and the inner cavity top surface 5A is higher than the inner cavity top surface 4A, so that the gas outlets are the highest points inside the cooler. If there is gas inside the cooler and the gas needs to be discharged, the gas will be discharged from the heat exchange core to the cooling liquid containing cavity to the first gas outlet or the second gas outlet in turn, and finally discharged to the outside of the cooler. The above arrangement can prevent the phenomenon of local gas collection at the highest point inside the cooler, and is beneficial to fully discharge the gas inside the cooler.

[0124] As shown in Figs. 6 and 7, the height of the inner cavity bottom surface 4B of the heat exchange core, the inner cavity bottom surface 5B of the cooling liquid containing cavity, and the inner cavity bottom surface 3B of the liquid injection / liquid discharge joint decreases in turn, i.e., the inner cavity bottom surface 3B is lower than the inner cavity bottom surface 5B, and the inner cavity bottom surface 5B is lower than the inner cavity bottom surface 4B, so that the liquid injection / liquid discharge joint is the lowest point inside the cooler. When the liquid inside the cooler needs to be discharged, the liquid will be discharged from the heat exchange core to the liquid injection / liquid discharge joint in turn, and finally discharged to the outside of the cooler. The above arrangement can fully drain the liquid inside the cooler.

[0125] As shown in Fig. 8, the first deflation joint 1 comprises a first aluminum sleeve 11, a first steel sleeve 12, a first sealing ring 14, and a screw (i.e. a first connecting member 13). The material of the vehicle-mounted transformer is generally aluminum. The first aluminum sleeve 11 is connected to the cooling liquid containing cavity by welding. The first steel sleeve 12 is connected to the first aluminum sleeve 11 by threading. Before connection, a fixing glue can be applied on the thread to prevent loosening while sealing. The first steel sleeve 12 is provided with a slot in which the first sealing ring 14 is placed, thereby preventing the first sealing ring 14 from sliding when the screw is tightened. The screw is connected to the first steel sleeve 12 by threading. The screw is internally provided with a through hole for deflation. The through hole forms a first airflow passage 133. When the screw is loosened, the through hole in the screw connects the inside of the cooler with the atmosphere, thereby allowing deflation. When the screw is tightened, the cooler can be better sealed. Meanwhile, the first steel sleeve 11 can effectively prevent the traditional steel screw from being broken due to being stuck when being twisted.

[0126] As shown in Fig. 9, the second deflation joint 2 comprises a second aluminum sleeve 21, a second steel sleeve 22, a second sealing ring 24, and a quick connector. The second aluminum sleeve 21, the second steel sleeve 22, and the second sealing ring 24 are similar to the corresponding components in the first deflation joint. The inner end of the quick connector is connected to the second steel sleeve 22 by threading. The outer end of the quick connector is provided with a protective sleeve 25 to prevent the connector from being damaged during operation and transportation. The second deflation joint is inserted into the female head or the male head of the external matching quick connector, thereby forming a passage to connect the inside of the cooler with the outside, allowing deflation or air extraction. When the external connector is disconnected, the cooler can be automatically sealed.

[0127] As shown in Fig. 10, the liquid injection / liquid discharge joint 3 comprises a third aluminum sleeve 31, a third steel sleeve 32, a third sealing ring 34, and a screw. The third aluminum sleeve 31, the third steel sleeve 32, and the third sealing ring 34 are similar to the corresponding components in the first deflation joint. The screw is connected to the third steel sleeve 32 by threading. When the liquid injection / liquid discharge joint 3 is disassembled, the liquid in the cooler can be discharged through the threaded hole in the third steel sleeve 32. When the screw is tightened, the cooler can be better sealed.

[0128] Preferably, the second steel sleeve 22 in the second deflation joint and the third steel sleeve 32 in the liquid injection / liquid discharge joint can be provided with consistent threading interfaces to facilitate the use of a unified model of the quick connector and improve universality. The first connecting member / second connecting member (e.g. the screw) in the first deflation joint / second deflation joint can also be replaced by a quick connector as needed.

[0129] The first steel sleeve 12, the second steel sleeve 22, and the third steel sleeve 32 can also be replaced by steel wire sleeves. The corresponding aluminum sleeves, steel sleeves, sealing rings, screws, and quick connectors in the first deflation joint 1, the second deflation joint 2, and the liquid injection / liquid discharge joint 3 can be provided with unified interfaces or models to increase universality and reduce spare parts.

[0130] The present application also relates to a method for online replacement of an oil cooler. The above-mentioned cooler 10 is connected with an oil injection device and a vacuum pumping device. When the cooler is in failure, it needs to be replaced online. The method for online replacement comprises the following steps:

[0131] (S1) Close the first valve 30 and the second valve 40, so that the cooler is completely isolated from the transformer tank.

[0132] (S2) Open the first gas discharge joint and the liquid injection / discharge joint, and discharge the liquid in the cooler to an external container. After the liquid is completely discharged, the failed cooler is removed.

[0133] (S3) After the new cooler is installed, the screw 2 of the liquid injection / discharge joint is replaced with a quick joint and is tightened.

[0134] (S4) The vacuum pumping device is connected with the second gas discharge joint through an external quick joint male or female head. The first gas discharge joint, the liquid injection / discharge joint, the first valve 30 and the second valve 40 are in a closed or tightened state. The vacuum pumping device is started to perform vacuum pumping.

[0135] (S5) When the vacuum degree reaches a set value, the oil injection device is connected with the liquid injection / discharge joint through an external quick joint male or female head. The inside of the cooler is injected with oil at a first liquid injection speed. As the height of the injected oil increases, the vacuum degree will decrease. Therefore, the oil injection is performed while the vacuum pumping device is operated at the same time.

[0136] (S6) When the liquid surface of the injected oil reaches a high height, the vacuum pumping may pump in oil and may damage the vacuum pumping device. At this time, the quick joint connected with the second gas discharge joint and the vacuum pumping device can be removed according to the situation to restore the sealing property of the second gas discharge joint.

[0137] (S7) The oil injection speed of the oil injection device is reduced to a second liquid injection speed for oil injection. At the same time, the hole screw (i.e., the first connecting piece provided with the first gas flow channel) of the first gas discharge joint is slowly opened until no gas is discharged from the first gas discharge joint.

[0138] (S8) The hole screw is tightened to restore the sealing property of the first gas discharge joint.

[0139] (S9) Finally, the first valve 30 and the second valve 40 are opened to make the cooler and the transformer tank communicate.

[0140] As shown in FIG. 8, FIG. 8(c), the first bleed joint 1 has a first screw sleeve 15 and a first connector 13 installed on the cooler; the inner cavity of the first screw sleeve 15 communicates with the inner cavity of the cooler 10; the first connector 13 is threadedly engaged with the inner cavity of the first screw sleeve 15, thereby closing the opening of the first screw sleeve 15 or communicating the inner cavity of the first screw sleeve 15 with the external atmosphere; the first connector 13 has a head 131 for closing the opening of the first screw sleeve 15 and an externally threaded rod 132 threadedly engaged with the inner cavity of the first screw sleeve 15, and the externally threaded rod 132 is provided with a first airflow passage 133 for communicating the inner cavity of the first screw sleeve 15 with the external atmosphere when the head 131 is not in contact with the first screw sleeve 15.

[0141] The first airflow passage 133 has a passage segment opening 1333 formed on the outer wall of the externally threaded rod 132. The first airflow passage 133 includes a first passage segment 1331 extending in the axial direction of the externally threaded rod 132, a second passage segment 1332 communicating with the first passage segment 1331, the extending direction of the second passage segment 1332 being perpendicular to the axial direction of the externally threaded rod 132, and the second passage segment 1332 having a passage segment opening 1333 formed on the outer wall of the externally threaded rod 132; the inner cavity of the first screw sleeve 15 communicates with the space outside the externally threaded rod 132 through the first passage segment 1331 and the second passage segment 1332 in sequence.

[0142] In the preferred embodiment, the step of changing the opening of the first bleed joint 1 from the closed state to the open state in step S7 is specifically:

[0143] (S71) when the length of the part not coinciding with the second projection in the first projection relative to the length of the first projection reaches a preset proportion p1, stop screwing the first connector 13;

[0144] (S72) when the stop time reaches a preset time t1, continue screwing the first connector 13 until the length of the part not coinciding with the second projection in the first projection relative to the length of the first projection is 1;

[0145] wherein p1∈[1 / 4, 1 / 2]; the first projection is the projection of the passage segment opening 1333 on the axial line of the externally threaded rod 132, and the second projection is the projection of the first screw sleeve 15 on the axial line of the externally threaded rod 132. The first passage segment 1331 can extend in the radial direction of the externally threaded rod 132. In this embodiment, p1 can be 1 / 3.

[0146] As shown in Fig. 8(a), when the first connecting member closes the first screw opening, the length of the part in the first projection R-13 that does not coincide with the second projection R-15 is less than 1 / 3 of the length of the first projection R-13. In step (S71), the first connecting member 13 is screwed so that the first connecting member moves away from the first screw.

[0147] As shown in Fig. 8(b), when the first connecting member moves to a position where the length of the part in the first projection R-13 that does not coincide with the second projection R-15 is 1 / 3 of the length of the first projection R-13, the screwing of the first connecting member 13 is stopped in step (S71) until the stopping time reaches a preset time t1. The value of t1 is, for example, in the range of 3-8 min. The screwing of the first connecting member 13 is continued until the length of the part in the first projection R-13 that does not coincide with the second projection R-15 is 1, i.e., the first projection R-13 and the second projection R-15 are completely misaligned.

[0148] The on-line replaceable cooler and the replacement method of the above-mentioned application can quickly and safely realize on-line replacement of the cooler, can sufficiently discharge air in the cooler, and ensure the safety of the transformer. The above-mentioned application greatly saves the period and cost generated by the traditional method of taking the transformer off the vehicle for maintenance due to failure of the cooler, and avoids the safety hazards and long period caused by insufficient air discharge in the ordinary normal-pressure oil injection mode. Meanwhile, the oil injection equipment does not need to be lifted to a very high height, thereby saving the operation space, reducing the requirement for the operation environment, and increasing the operability on site.

[0149] The above-mentioned cooler can be used in coolers of different structural forms such as the tube type, the plate type, the plate-fin type, and the tube-fin type, and can also be used in coolers on both sides of a cooling liquid collecting box. The above-mentioned on-line replaceable cooler and the replacement method are suitable for both the motor train unit traction transformer and the locomotive traction transformer and other types of equipment. Embodiment 2

[0150] As shown in Fig. 11, the difference between the present embodiment 2 and embodiment 1 is that the first air discharge joint 1 and the second air discharge joint 2 are located on the top surface (upper surface) of the cooling liquid containing cavity 5, and the liquid injection / drainage joint 3 is located on the bottom surface (lower surface) of the cooling liquid containing cavity 5. If the space above and below the cooler of the vehicle allows, the air discharge joint and the liquid injection / drainage joint can be arranged on the top surface and the bottom surface of the cooler, respectively, as shown in Fig. 11. Embodiment 3

[0151] As shown in Figs. 12-14, the difference between the present embodiment 3 and embodiment 2 is that both sides of the heat exchange core 4 are provided with cooling liquid containing cavities 5 which are in communication with the cooling liquid passages of the heat exchange core 4; the inlet and outlet of the cooler 10 are located in one of the cooling liquid containing cavities 5. The second gas discharge joint 2 and the liquid injection / drain joint 3 are arranged in different cooling liquid containing cavities 5.

[0152] In the present embodiment 3, the second gas discharge joint 2 and the liquid injection / drain joint 3 can be arranged in different cooling liquid containing cavities 5. When the cooler is in communication with the transformer tank, the cooling liquid enters one side of the cooling liquid containing cavities 5 from the first valve 30 through the first pipeline 101, enters the other side of the cooling liquid containing cavities 5 after passing through the heat exchange core 4, returns to the one side of the cooling liquid containing cavities 5 after passing through the heat exchange core 4 again, and flows out from the second valve 40 through the second pipeline 102. The cooling liquid flow direction is shown by dashed arrows in Fig. 12.

[0153] Preferably, each cooling liquid containing cavity 5 is provided with a first gas discharge joint 1.

[0154] The cooling liquid containing cavities 5 on both sides of the heat exchange core 4 are respectively a first cooling liquid containing cavity 51 and a second cooling liquid containing cavity 52; the cooling liquid passages include at least one first cooling liquid passage 43 and at least one second cooling liquid passage 44, each first cooling liquid passage 43 and each second cooling liquid passage 44 are in communication with the first cooling liquid containing cavity 51 and the second cooling liquid containing cavity 52; a passage valve is used to open or close each second cooling liquid passage 44; the liquid injection / drain joint 3 is arranged in the first cooling liquid containing cavity 51, and the second gas discharge joint 2 is arranged in the second cooling liquid containing cavity 52. The inlet and outlet of the cooler 10 are arranged in the first cooling liquid containing cavity 51.

[0155] As shown in Figs. 12-15, in the present embodiment 3, a partition plate 510 is arranged in the first cooling liquid containing cavity 51, the partition plate 510 divides the inner cavity of the first cooling liquid containing cavity 51 into a first cavity body 511 and a second cavity body 512 which are independent of each other, the inlet of the cooler 10 is arranged towards the first cavity body 511, the outlet of the cooler 10 is arranged towards the second cavity body 512, the inlet of the cooler 10 sequentially passes through the first cavity body 511, the cooling liquid passages in the heat exchange core 4 which are arranged towards the first cavity body 511 (i.e. each first cooling liquid passage 43), the second cooling liquid containing cavity 52, the cooling liquid passages in the heat exchange core 4 which are arranged towards the second cavity body 512 (i.e. each second cooling liquid passage 44), the second cavity body 512, and the outlet of the cooler 10.

[0156] The cooling liquid channel comprises at least one first cooling liquid channel 43 arranged towards the first cavity 511, and at least one second cooling liquid channel 44 arranged towards the second cavity 512, each first cooling liquid channel 43 and each second cooling liquid channel 44 being in communication with the first cooling liquid containing cavity 51 and the second cooling liquid containing cavity 52; the cooler further comprises a channel valve (not shown in the figure) for opening / closing each second cooling liquid channel 44; the liquid injection / liquid discharge joint 3 is arranged in the first cooling liquid containing cavity 51, and the second gas discharge joint 2 is arranged in the second cooling liquid containing cavity 52.

[0157] During the process of starting the vacuumizing device 50 until the vacuum degree in the cavity of the cooler 10 reaches the set vacuum degree, each first cooling liquid channel 43 and each second cooling liquid channel 44 are in an open state.

[0158] The step (S5) further comprises: before injecting liquid into the cooler 10 at the first liquid injection speed, changing each second cooling liquid channel 44 from an open state to a closed state; when the liquid level in the second cooling liquid containing cavity 52 reaches a second set height, changing each second cooling liquid channel 44 from a closed state to an open state. The second set height is higher than the height at which each first cooling liquid channel 43 is located, and is higher than the height at which each second cooling liquid channel 44 is located.

[0159] In the step (S6), the liquid level in the cavity of the cooler 10 reaching the first set height means that the liquid level in the first cooling liquid containing cavity 51 and the liquid level in the second cooling liquid containing cavity 52 both reach the first set height; the first set height is not lower than the second set height.

[0160] In the embodiment, the partition plate 510 is arranged horizontally, i.e. the cavity in the heat exchange core 4 is divided into the first cavity 511 located above and the second cavity 512 located below, and the liquid inlet of the cooler 10 is located higher than the height position of the partition plate 510, and the liquid outlet of the cooler 10 is located lower than the height position of the partition plate 510, so that the liquid flowing into the first cooling liquid containing cavity 51 from the liquid inlet is more likely to enter the cooling liquid channel of the first cavity 511, and the liquid flowing out of the cooling liquid channel of the second cavity 512 is more likely to flow out of the liquid outlet, thereby forming a flow path of the cooling liquid. Embodiment 4

[0161] As shown in FIGS. 16-17, the difference between the embodiment 4 and the embodiment 3 is that the partition plate 510 is arranged vertically, i.e. the first cavity 511 and the second cavity 512 are located on the left and right sides of the partition plate respectively, and the liquid inlet of the cooler 10 is located on the same side as the first cavity 511, and the liquid outlet of the cooler 10 is located on the same side as the second cavity 512.

[0162] It should be noted that each of the embodiments in the specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0163] The above describes the embodiments of the present application in detail, but the above description is only the preferred embodiments of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application should still fall within the scope of the present application. After reading the present application, those skilled in the art can make various equivalent modifications to the present application, which fall within the scope defined by the claims of the present application. In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

Claims

1. A cooler for a transformer, characterized by: The inlet of the cooler (10) is detachably connected with one end of the first valve (30), and the outlet of the cooler (10) is detachably connected with one end of the second valve (40); the other end of the first valve (30) and the other end of the second valve (40) are respectively used for communicating with the cooling liquid outlet and the cooling liquid inlet of the transformer tank (20); the cooler (10) is provided with a first gas discharge joint (1) for communicating with the external atmosphere, a second gas discharge joint (2) for connecting with the vacuumizing device (50), and a liquid injection / liquid discharge joint (3) for connecting with the liquid injection device (60) or discharging the liquid in the cooler; the first gas discharge joint (1), the second gas discharge joint (2) and the liquid injection / liquid discharge joint (3) all communicate with the inner cavity of the cooler (10); the first gas discharge joint (1) and the second gas discharge joint (2) are installed on the upper part of the cooler, and the liquid injection / liquid discharge joint (3) is installed on the lower part of the cooler (10).

2. The cooler of claim 1, wherein: The cooler (10) comprises a heat exchange core (4) and a cooling liquid containing cavity (5) arranged adjacent to the heat exchange core (4); the heat exchange core (4) has at least one cooling liquid channel, each of which communicates with the cooling liquid containing cavity (5); the inlet and the outlet of the cooler (10) are both located on the cooling liquid containing cavity (5); the first gas discharge joint (1) and the second gas discharge joint (2) are installed on the upper part of the cooling liquid containing cavity (5), and the liquid injection / liquid discharge joint (3) is installed on the lower part of the cooling liquid containing cavity (5); the first gas discharge joint (1), the second gas discharge joint (2) and the liquid injection / liquid discharge joint (3) all communicate with the inner cavity of the cooling liquid containing cavity (5); preferably, the first gas discharge joint (1) and the second gas discharge joint (2) are arranged on the top surface of the cooling liquid containing cavity (5); and the liquid injection / liquid discharge joint (3) is arranged on the bottom surface of the cooling liquid containing cavity (5).

3. The cooler of claim 2, wherein: The heat exchange core (4) is provided with the cooling liquid containing cavity (5) communicating with the cooling liquid channel of the heat exchange core (4) on both sides; the cooling liquid containing cavities (5) on both sides of the heat exchange core (4) are respectively the first cooling liquid containing cavity (51) and the second cooling liquid containing cavity (52); the inlet and the outlet of the cooler (10) are both arranged in the first cooling liquid containing cavity (51); Preferably, the second gas discharge joint (2) and the liquid injection / liquid discharge joint (3) are arranged in different cooling liquid containing cavities (5); Preferably, each cooling liquid containing cavity (5) is provided with the first gas discharge joint (1); Preferably, each cooling liquid containing cavity (5) is provided with the first gas discharge joint (1). Preferably, a partition (510) is arranged in the first cooling liquid accommodating cavity (51), the partition (510) separates the inner cavity of the first cooling liquid accommodating cavity (51) into first and second cavities (511, 512) which are independent of each other, the liquid inlet of the cooler (10) is arranged towards the first cavity (511), the liquid outlet of the cooler (10) is arranged towards the second cavity (512), the liquid inlet of the cooler (10) is in communication with the liquid outlet of the cooler (10) through the first cavity (511), a cooling liquid passage arranged in the heat exchange core (4) towards the first cavity (511), the second cooling liquid accommodating cavity (52), a cooling liquid passage arranged in the heat exchange core (4) towards the second cavity (512), and the second cavity (512) in sequence; more preferably, the cooling liquid passage comprises at least one first cooling liquid passage (43) arranged towards the first cavity (511) and at least one second cooling liquid passage (44) arranged towards the second cavity (512), each first cooling liquid passage (43) and each second cooling liquid passage (44) are in communication with the first cooling liquid accommodating cavity (51) and the second cooling liquid accommodating cavity (52); the cooler further comprises a passage valve for opening / closing each second cooling liquid passage (44); the liquid injection / liquid discharge connector (3) is arranged in the first cooling liquid accommodating cavity (51), and the second gas discharge connector (2) is arranged in the second cooling liquid accommodating cavity (52).

4. The cooler of claim 2, wherein: The height of the inner cavity top surface (4A) of the heat exchange core, the inner cavity top surface of the cooling liquid accommodating cavity provided with the first gas discharge connector (1), and the inner cavity top surface (1A) of the first gas discharge connector increases in sequence; the height of the inner cavity top surface (4A) of the heat exchange core, the inner cavity top surface of the cooling liquid accommodating cavity provided with the second gas discharge connector (2), and the inner cavity top surface (2A) of the second gas discharge connector increases in sequence; the height of the inner cavity bottom surface (4B) of the heat exchange core, the inner cavity bottom surface (5B) of the cooling liquid accommodating cavity provided with the liquid injection / liquid discharge connector (3), and the inner cavity bottom surface (3B) of the liquid injection / liquid discharge connector decreases in sequence.

5. Cooler according to any one of claims 1-4, characterized in that: The liquid level height sensor for measuring the liquid level height in the cooling liquid accommodating cavity (5) is further included, and the output end of the liquid level height sensor and the control end of the vacuumizing device (50) are electrically connected with the controller.

6. Cooler according to any one of claims 1-4, characterized in that: The first air release joint (1) has a first screw sleeve (15) installed on the cooler, a first connecting piece (13); the inner cavity of the first screw sleeve (15) is communicated with the inner cavity of the cooler (10); the first connecting piece (13) is threadedly matched with the first screw sleeve (15), thereby closing the opening of the first screw sleeve (15) or communicating the inner cavity of the first screw sleeve (15) with the external atmosphere; the first connecting piece (13) has a head (131) for closing the opening of the first screw sleeve (15), an outer threaded rod (132) threadedly matched with the first screw sleeve (15), and a first air flow channel (133) formed on the outer threaded rod (132) for communicating the inner cavity of the first screw sleeve (15) with the external atmosphere when the head (131) is not in contact with the first screw sleeve (15); the second air release joint (2) has a second screw sleeve installed on the cooler and a second connecting piece (23) for being connected with the vacuumizing device (50); the inner cavity of the second screw sleeve is communicated with the inner cavity of the cooler (10); the second connecting piece (23) is threadedly matched with the second screw sleeve; the liquid injection / liquid discharge joint (3) has a third screw sleeve installed on the cooler and a third connecting piece for being connected with the liquid injection device or for closing the opening of the third screw sleeve; the inner cavity of the third screw sleeve is communicated with the inner cavity of the cooler (10); the third connecting piece is threadedly matched with the third screw sleeve; Preferably, at least one of the first screw sleeve, the second screw sleeve and the third screw sleeve comprises an aluminum sleeve installed on the cooler and a steel sleeve fixedly installed on the inner side of the aluminum sleeve, and the inner side of the steel sleeve forms an inner thread matched with the corresponding connecting piece; the material of the corresponding connecting piece is steel; Preferably, the second connecting piece is a quick connector; Preferably, the third connecting piece comprises a fastener (33) for closing the opening of the third screw sleeve and a quick connector for being connected with the liquid injection device, and the inner thread of the third screw sleeve is switchably connected with the quick connector and the fastener (33); more preferably, the fastener (33) has a fastener head (331) for closing the opening of the third screw sleeve and a fastener outer threaded rod (332) for being matched with the inner thread of the third screw sleeve, and a second air flow channel is formed on the fastener outer threaded rod (332) for communicating the inner cavity of the third screw sleeve with the external atmosphere when the fastener head (331) is not in contact with the third screw sleeve.

7. A rail vehicle, characterized by: The transformer is a traction transformer of a railway vehicle.

8. A method of online replacement of a chiller, characterized by: The cooler is the cooler according to any one of claims 1-6; the online replacement method comprises: (S1) closing the first valve (30) and the second valve (40); (S2) disconnecting the cooler to be replaced from the first valve (30) and the second valve (40) and dismounting the cooler to be replaced; (S3) connecting the liquid inlet of the replaced cooler (10) with one end of the first valve (30) and connecting the liquid outlet of the replaced cooler (10) with one end of the second valve (40); (S4) connecting the second gas exhaust joint (2) with the vacuumizing device (50), and the first gas exhaust joint (1) and the liquid injection / liquid discharge joint (3) are in the closed state, and starting the vacuumizing device (50); (S5) when the vacuum degree of the inner cavity of the cooler (10) reaches the set vacuum degree, connecting the liquid injection device (60) with the liquid injection / liquid discharge joint (3), and injecting liquid into the cooler (10) at a first liquid injection speed; (S6) when the liquid level of the inner cavity of the cooler (10) reaches the first set height, closing the vacuumizing device (50), and changing the second gas exhaust joint (2) from the open state to the closed state; (S7) injecting liquid into the cooler (10) at a second liquid injection speed, and changing the first gas exhaust joint (1) from the closed state to the open state until the liquid injection is completed, wherein the second liquid injection speed is less than the first liquid injection speed; (S8) after the liquid injection is completed, changing the first gas exhaust joint (1) from the open state to the closed state; (S9) opening the first valve (30) and the second valve (40).

9. The on-line replacement method according to claim 8, characterized in that: The cooler (10) comprises a heat exchange core (4) and a cooling liquid containing cavity (5) arranged adjacent to the heat exchange core (4), the heat exchange core (4) has at least one cooling liquid passage, each cooling liquid passage is communicated with the cooling liquid containing cavity (5); the liquid inlet and the liquid outlet of the cooler (10) are located in the cooling liquid containing cavity (5); the height of the inner cavity top surface (4A) of the heat exchange core, the inner cavity top surface of the cooling liquid containing cavity provided with the first gas exhaust joint (1), and the inner cavity top surface (1A) of the first gas exhaust joint are sequentially increased; the first gas exhaust joint (1) has a first screw sleeve (15) mounted on the cooler and a first connecting piece (13); the inner cavity of the first screw sleeve (15) is communicated with the inner cavity of the cooler (10); the first connecting piece (13) is threadedly connected with the first screw sleeve (15), thereby closing the opening of the first screw sleeve (15) or communicating the inner cavity of the first screw sleeve (15) with the external atmosphere; the first connecting piece (13) has a head (131) for closing the opening of the first screw sleeve (15) and an outer threaded rod portion (132) threadedly connected with the first screw sleeve (15), the outer threaded rod portion (132) is provided with a first air flow channel (133) for communicating the inner cavity of the first screw sleeve (15) with the external atmosphere when the head (131) is not in contact with the first screw sleeve (15); the first air flow channel (133) has a channel segment opening (1333) formed on the outer wall of the outer threaded rod portion (132); In the step (S7), the step of changing the first gas exhaust joint (1) from the closed state to the open state is specifically: (S71) screwing the first connecting piece (13), and when the ratio of the length of the part not coinciding with the second projection in the first projection to the length of the first projection reaches a preset ratio p1, stopping screwing the first connecting piece (13); (S72) when the stop time reaches a preset time t1, continuing to screw the first connecting piece (13) until the ratio of the length of the part not coinciding with the second projection in the first projection to the length of the first projection is 1. Wherein, p1∈[1 / 4, 1 / 2]; the first projection is the projection of the channel segment opening (1333) on the axis of the outer threaded rod (132), and the second projection is the projection of the first sleeve (15) on the axis of the outer threaded rod (132); preferably, when the ratio reaches the preset ratio p1, the channel segment opening (1333) is located at the top end of the first air flow channel (133).

10. The on-line replacement method of claim 8, wherein: The cooler (10) comprises a heat exchange core (4), a cooling liquid containing cavity (5) arranged adjacent to the heat exchange core (4), the heat exchange core (4) has at least one cooling liquid channel; the first gas discharge joint (1), the second gas discharge joint (2) and the liquid injection / discharge joint (3) are all in communication with the inner cavity of the cooling liquid containing cavity (5); the second gas discharge joint (2) and the liquid injection / discharge joint (3) are arranged in different cooling liquid containing cavities (5); the heat exchange core (4) is provided with cooling liquid containing cavities (5) on both sides and in communication with the cooling liquid channels of the heat exchange core (4), the cooling liquid containing cavities (5) on both sides of the heat exchange core (4) are respectively a first cooling liquid containing cavity (51) and a second cooling liquid containing cavity (52); the liquid injection / discharge joint (3) is installed at the lower part of the first cooling liquid containing cavity (51), and the second gas discharge joint (2) is installed at the upper part of the second cooling liquid containing cavity (52); the liquid inlet and the liquid outlet of the cooler (10) are arranged in the first cooling liquid containing cavity (51); a partition plate (510) is arranged in the first cooling liquid containing cavity (51), the partition plate (510) divides the inner cavity of the first cooling liquid containing cavity (51) into a first cavity (511) and a second cavity (512) which are independent of each other; the liquid inlet of the cooler (10) is arranged towards the first cavity (511), and the liquid outlet of the cooler (10) is arranged towards the second cavity (512); the liquid inlet of the cooler (10) is in communication with the liquid outlet of the cooler (10) in sequence through the first cavity (511), the cooling liquid channel of the heat exchange core (4) arranged towards the first cavity (511), the second cooling liquid containing cavity (52), the cooling liquid channel of the heat exchange core (4) arranged towards the second cavity (512) and the second cavity (512); the cooling liquid channel comprises at least one first cooling liquid channel (43) arranged towards the first cavity (511) and at least one second cooling liquid channel (44) arranged towards the second cavity (512), each first cooling liquid channel (43) and each second cooling liquid channel (44) are in communication with the first cooling liquid containing cavity (51) and the second cooling liquid containing cavity (52); During the process that the vacuumizing device (50) is started until the vacuum degree of the inner cavity of the cooler (10) reaches the set vacuum degree, each first cooling liquid channel (43) and each second cooling liquid channel (44) are in an open state. The step (S5) further comprises: before the cooler (10) is filled with the first coolant at the first filling speed, changing each second coolant passage (44) from an open state to a closed state; when the liquid level in the second coolant containing cavity (52) reaches a second set height, changing each second coolant passage (44) from the closed state to the open state; the second set height is higher than the height at which each first coolant passage (43) is located and higher than the height at which each second coolant passage (44) is located; In the step (S6), the liquid level in the inner cavity of the cooler (10) reaches the first set height, which means that the liquid level in the first coolant containing cavity (51) and the liquid level in the second coolant containing cavity (52) both reach the first set height; the first set height is not lower than the second set height. Preferably, the first cavity (511) is located below the second cavity (512). Preferably, the partition plate (510) extends in the height direction of the first coolant containing cavity (51), and the first cavity (511) and the second cavity (512) are located on both sides of the partition plate (510).

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