Sealing device for constant cooling water tank and using method

Abstract

The invention relates to the technical field of stator cooling water tanks, and discloses a stator cooling water tank sealing device and a using method. The sealing device comprises an automatic adjusting valve body and an air supplementing device which are communicated with a stator cooling water tank; the automatic adjusting valve body comprises a plugging piston, an inner sleeve, an upper limiting ejector pin, a lower limiting ejector pin, an outer sleeve, an upper limiting ejector plate and a lower limiting ejector plate. The external sleeve is communicated with the top of the constant cooling water tank; the plugging piston is arranged in the outer sleeve to form slidable sealing connection, and an upper limiting ejector pin and a lower limiting ejector pin are arranged at the two ends of the plugging piston and correspond to an upper limiting top plate and a lower limiting top plate which are fixed to the constant cold water tank respectively. An inner sleeve is arranged around the plugging piston; an air suction hole is formed in the upper part of the inner sleeve, and a pressure relief hole is formed in the lower part of the inner sleeve. The cold water tank is sealed and internal and external air pressure is balanced by means of up-down floating of the valve, and pressure and temperature balance of the water tank is maintained by means of multiple states of the air suction hole, the pressure relief hole and the air supply device.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling water tanks, and in particular to a cooling water tank sealing device and a use method thereof. Background Art

[0002] The stator cooling water tank is a key component of the generator stator cooling system. It is responsible for storing cooling water and distributing the cooling water to the stator winding and high-voltage bushing on the outgoing line side of the generator when needed to ensure that these components are properly cooled. Through the continuous high-purity water flow, the stator cooling water system can effectively remove the heat generated by the generator coil due to current loss, thereby keeping the generator coil running at a safe operating temperature and preventing damage caused by overheating.

[0003] Since the ventilation port on the top of the cooling water tank is usually equipped with a sealing structure, the purpose is to isolate the outside air and avoid pollution and corrosion. However, this sealing structure also causes the air pressure inside the tank to be higher than the constant value. High air pressure may have a negative impact on the diversion of carbon dioxide and cooling water, affecting the cooling effect and the stable operation of the system. High air pressure may have a negative impact on the diversion of carbon dioxide and cooling water, affecting the cooling effect and the stable operation of the system.

[0004] Although the sealing structure effectively isolates the outside air, it also brings about the problem of increased air pressure. This requires finding a balance in design and use, maintaining the necessary sealing while avoiding excessive air pressure. The dissolution of carbon dioxide not only affects the pH value of the cooling water, but may also affect the water quality and cooling effect. In the long run, this will lead to increased corrosion of the generator coil and shorten the service life of the equipment. The existing sealing structure is easily affected by the heat dissipation and pressure changes in the cooling water tank, lacks adaptability and stability, and the accuracy and reliability of automatic adjustment need to be improved. Summary of the invention

[0005] In order to solve the existing problems, the present invention provides a cooling water tank sealing device and a method of use which are reasonably designed, practical and convenient. The device aims to rely on the natural gravity of the automatic regulating valve to effectively balance the air pressure inside and outside the cooling water tank through the cooperation of the ejector pin and the limiting top plate, and uses an air replenishing device to further maintain the air pressure and temperature balance inside the cooling water tank.

[0006] In order to achieve the above object, the present invention provides the following technical solutions.

[0007] A cooling water tank sealing device comprises an automatic regulating valve body and an air supply device connected with the cooling water tank; the automatic regulating valve body comprises a sealing piston, an internal sleeve, an upper limit ejector pin, a lower limit ejector pin, an external sleeve, an upper limit top plate and a lower limit top plate; the external sleeve is connected to the top of the cooling water tank; the sealing piston is arranged inside the external sleeve to form a slidable sealing connection, and an upper limit ejector pin and a lower limit ejector pin are arranged at both ends of the sealing piston, respectively corresponding to the upper limit top plate and the lower limit top plate fixed on the cooling water tank; the sealing piston is surrounded by an internal sleeve; the upper part of the internal sleeve is provided with an air suction hole, and the lower part of the internal sleeve is provided with a pressure relief hole.

[0008] As a further improvement of the present invention, a counterweight block is provided on the blocking piston.

[0009] As a further improvement of the present invention, the weight of the counterweight is selected according to the atmospheric pressure exerted on the bottom of the blocking piston and the weight of the automatic regulating valve body.

[0010] As a further improvement of the present invention, the distance between the upper limit top plate and the lower limit top plate is not greater than the sum of the length of the external sleeve, the length of the upper limit ejector pin and the length of the lower limit ejector pin.

[0011] As a further improvement of the present invention, it also includes a lubricating oil layer; the lubricating oil layer is arranged between the blocking piston and the external sleeve to form a seal.

[0012] As a further improvement of the present invention, the gas replenishing device includes a gas storage bottle, a replenishing pipeline and an electric valve arranged on the replenishing pipeline; the gas storage bottle replenishes gas to the upper part of the inner cavity of the cooling water tank through the replenishing pipeline to fill the air pressure difference inside and outside the cooling water tank.

[0013] As a further improvement of the present invention, it also includes a centralized control device; the centralized control device includes a signal display and a control unit, an upper position sensor, an upper position signal cable, a lower position sensor, a lower position signal cable and an electric valve detection cable; the upper position sensor and the lower position sensor are respectively arranged at the upper edge and the lower edge of the external sleeve; the upper position sensor and the lower position sensor transmit the signal of the position of the automatic regulating valve body to the signal display through the upper position signal cable and the lower position signal cable respectively.

[0014] As a further improvement of the present invention, the electric valve is electrically connected to the signal display via an electric valve detection cable.

[0015] As a further improvement of the present invention, an upper position mark and a lower position mark of the automatic regulating valve are respectively set at the upper edge and the lower edge of the inner sleeve, and the lower position mark and the upper position mark are used to provide signals to the upper position sensor and the lower position sensor when the automatic regulating valve shifts.

[0016] In a second aspect, the present invention further discloses a method for using a cooling water tank sealing device, comprising the following steps: The automatic regulating valve body balances the internal pressure of the cooling water tank by floating up and down. When the air pressure in the cooling water tank is too high, the upper limit pin of the blocking piston touches the upper limit top plate of the cooling water tank, and the pressure relief hole discharges the excess gas inside the cooling water tank; after the automatic regulating valve body falls back, according to the degree of fall back, the air supply device is selected to enable the automatic regulating valve body to be in the middle position of the external casing; When the air pressure in the cooling water tank is too low, the lower limit pin of the sealing piston touches the lower limit top plate of the cooling water tank, and the air intake hole sucks air into the cooling water tank to balance the air pressure inside and outside the cooling water tank; the air supply device is activated so that the automatic regulating valve body is in the middle position of the external sleeve.

[0017] The present invention has the following beneficial effects: Automatic adjustment and sealing of the cooling water tank are achieved through the sealing piston, upper and lower limit pins and upper and lower limit top plate structures; this structure can ensure that the water tank can maintain a good sealing state at different water levels, prevent water leakage, and improve the stability and safety of the system; the setting of the air replenishing device, including the gas storage bottle, the replenishing pipeline and the electric valve, can fill the air pressure difference between the inside and outside of the cooling water tank and maintain the stability of the air pressure inside the water tank; the air replenishing device can prevent damage or leakage of the water tank caused by changes in air pressure; the addition of the internal sleeve enhances the stability of the sealing piston, helps to reduce friction and wear, and extends the service life of the device; the design of the air intake hole and the pressure relief hole enables the device to self-adjust according to changes in internal pressure, thereby improving the reliability and safety of the system.

[0018] Preferably, a counterweight block is provided on the blocking piston, so that the total mass of the automatic regulating valve body can be adjusted to meet the sealing requirements under different conditions, thereby improving the versatility and adaptability of the device.

[0019] Preferably, a specific proportional relationship between the total mass of the automatic regulating valve body and the bottom area of ​​the blocking piston ensures that the device can maintain a good sealing effect under various working conditions. This is the best matching ratio obtained through precise calculation.

[0020] Preferably, the distance design between the upper limit top plate and the lower limit top plate ensures the stability of the automatic regulating valve during operation, prevents damage caused by excessive movement, and ensures long-term stable operation.

[0021] Preferably, the provision of the lubricating oil layer effectively reduces the friction between the sealing piston and the external sleeve, which not only improves the smoothness of operation, but also helps to protect the device components and extend the maintenance cycle.

[0022] Preferably, the introduction of the gas replenishing device allows gas to be replenished into the cooling water tank through the gas storage bottle when necessary to maintain the pressure balance inside the water tank and avoid sealing problems caused by pressure differences.

[0023] Preferably, the setting of the centralized control device realizes real-time detection and automatic control of the position of the automatic regulating valve and the opening and closing of the electric valve, which is convenient for the operator to understand the equipment status in time, improves the management efficiency and the information level of the system.

[0024] Preferably, the upper and lower position markings of the automatic regulating valve cooperate with the sensor to form a closed-loop control system, which further improves the intelligence level of the device and ensures the accuracy of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 It is a structural schematic diagram of a cooling water tank sealing device according to an embodiment; Figure 2 It is a schematic diagram of the middle, lower, upper and middle-lower positions of a fixed cooling water tank sealing device described in an embodiment; Among them, 1. cold water tank; 2. automatic regulating valve body; 3. gas cylinder; 4. centralized control device; 101. cold water tank outlet pipeline; 102. cold water tank inlet pipeline; 201. blocking piston; 202. upper limit ejector pin; 203. lower limit ejector pin; 204. internal sleeve; 205. air intake hole; 206. pressure relief hole; 207. counterweight; 208. external sleeve; 209. upper limit top plate; 210. lower limit top plate; 301. supplementary pipeline; 302. electric valve; 401. upper position mark; 402. upper position sensor; 403. upper position signal cable; 404. lower position mark; 405. lower position sensor; 406. lower position signal cable; 407. electric valve detection cable. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0029] Example like Figure 1 As shown, the present invention discloses a sealing device for a cooling water tank 1, comprising an automatic regulating valve body 2 and an air supply device connected to the cooling water tank 1; the automatic regulating valve body 2 comprises a blocking piston 201, an internal sleeve 204, an upper limit ejector pin 202, a lower limit ejector pin 203, an external sleeve 208, an upper limit ejector plate 209 and a lower limit ejector plate 210. The cooling water tank 1 is provided with a cooling water tank outlet pipeline 101 and a cooling water tank inlet pipeline 102, which are used to send medium fluid in and out of the water tank.

[0030] The external sleeve 208 is in the shape of a circular tube and is connected to the top of the cooling water tank 1 , which helps the low-density gas to be discharged from the top of the cooling water tank 1 .

[0031] The blocking piston 201 is disc-shaped, with outer edges on both sides extending out to slidably contact the inner wall of the external sleeve 208. The blocking piston 201 is arranged inside the external sleeve 208 to form a sealed connection. The sealed connection ensures that the blocking piston 201 isolates the external air and heat, ensures the stability of the internal pressure of the cooling water tank 1, and prevents carbon dioxide in the air from entering the cooling water tank 1 and dissolving in the cooling water. At the same time, the blocking piston 201 can slide up and down along the external sleeve 208 to adjust the air pressure level inside the cooling water tank 1 in real time and maintain the balance of internal and external air pressure.

[0032] An upper limit pin 202 and a lower limit pin 203 are provided at both ends of the blocking piston 201. The needle heads of the upper and lower limit pins can be set to be flat, respectively corresponding to the upper limit top plate 209 and the lower limit top plate 210 fixed on the cold water tank 1; the distance between the upper limit top plate 209 and the lower limit top plate 210 is not greater than the sum of the length of the external sleeve 208, the length of the upper limit pin 202 and the length of the lower limit pin 203. This design prevents damage caused by excessive movement and avoids the blocking piston 201 from being separated from the surrounding seal of the external sleeve 208, thereby ensuring long-term stable operation.

[0033] The blocking piston 201 is surrounded by an internal sleeve 204, which is in the shape of a circular tube, forming an extension of the outer edges extending from both sides of the disc-shaped blocking piston 201, so that the blocking piston 201 and the external sleeve 208 have a larger contact surface; the upper part of the internal sleeve 204 is provided with an air intake hole 205, and the lower part of the internal sleeve 204 is provided with a pressure relief hole 206. The size of the air intake hole 205 and the pressure relief hole 206 is small enough that the air replenishment of the air replenishment device will not be directly discharged from the box body once opened. The addition of the internal sleeve 204 enhances the stability of the blocking piston 201, helps to reduce friction and wear, and prolongs the service life of the device; the design of the air intake hole 205 and the pressure relief hole 206 enables the device to self-adjust according to the internal pressure changes, thereby improving the reliability and safety of the system.

[0034] The blocking piston 201 is provided with a counterweight 207 to increase or decrease the total mass of the automatic regulating valve body 2, and can meet the needs of blocking pistons 201 of different sizes and automatic regulating valve bodies 2 of different masses. Specifically, the total mass of the automatic regulating valve body 2 is the sum of the masses of the automatic regulating valve body 2 and the counterweight 207; according to the calculation of the standard atmospheric pressure, the kilograms of the total mass of the automatic regulating valve body 2 is 10132 times the square meters of the bottom area of ​​the blocking piston 201, so as to maintain the balance of internal and external pressures of the constant cooling water tank 1 under atmospheric pressure conditions; this multiple relationship also depends on the state of the internal and external temperature and air pressure of the constant cooling water tank 1.

[0035] A lubricating oil layer may also be provided between the blocking piston 201 and the external sleeve 208 to form a seal on the contact surface and provide lubrication for the relative movement between the blocking piston 201 and the external sleeve 208 .

[0036] The gas supply device includes a gas cylinder 3, a supply pipeline 301, and an electric valve 302 disposed on the supply pipeline 301; the gas cylinder 3 supplies gas to the upper part of the inner cavity of the cooling water tank 1 through the supply pipeline 301 to fill the pressure difference between the inside and outside of the cooling water tank 1 to avoid device failure or damage caused by the pressure difference. The gas cylinder 3 is generally filled with nitrogen.

[0037] The device also includes a centralized control device 4; the centralized control device 4 includes a signal display and control unit, an upper position sensor 402, an upper position signal cable 403, a lower position sensor 405, a lower position signal cable 406 and an electric valve detection cable 407.

[0038] like Figure 1 As shown, the upper position sensor 402 and the lower position sensor 405 are respectively arranged at the upper edge and the lower edge of the external sleeve 208; the upper position sensor 402 and the lower position sensor 405 transmit the signal of the position of the automatic regulating valve body 2 to the signal display and the control unit through the upper position signal cable 403 and the lower position signal cable 406 respectively; the electric valve 302 transmits the signal of the opening and closing of the electric valve 302 to the signal display through the electric valve detection cable 407; the signal display provides signals for the operator.

[0039] The lower position mark 404 and the upper position mark 401 of the automatic regulating valve are also respectively arranged at the upper edge and the lower edge of the inner sleeve 204, and the lower position mark 404 and the upper position mark 401 are used to provide signals to the lower position sensor 405 and the upper position sensor 402 when the automatic regulating valve is shifted. The way in which the upper position mark 401 and the lower position mark 404 provide signals is described in the working principle below. The control unit controls the opening and closing of the electric valve 302 according to the positions of the lower position mark 404 and the upper position mark 401 of the automatic regulating valve. When the lower position mark 404 touches the lower position sensor 405, the lower position sensor 405 will transmit an alarm signal to the control unit; the control unit sends a low pressure warning signal, and sends an opening control signal to the electric valve 302 through the electric valve detection cable 407, and the electric valve 302 is opened. At this time, the gas storage cylinder 3 will transport the stored gas to the fixed cold water tank 1 through the supplementary pipeline 301 to balance the air pressure in the fixed cold water tank 1; the fixed cold water tank can be restored from the low pressure warning state to the normal state. When the automatic regulating valve body 2 rises back to the middle position of the external sleeve 208, the upper position mark 401 is below the upper position sensor 402, and the lower position mark 404 is above the lower position sensor 405 of the automatic regulating valve; the lower position sensor 405 will stop alarming the control unit, and the control unit will send a closing control signal to the electric valve 302 through the electric valve detection cable 407 to close the electric valve 302. At this time, the gas cylinder 3 will stop transporting the stored gas to the constant cooling water tank 1 via the supplementary pipeline 301.

[0040] Optionally, the upper part of the inner sleeve 204 is provided with an air intake hole 205, and the lower part of the inner sleeve 204 is provided with a pressure relief hole 206. Electric paddles can be provided on the air intake hole 205 and the pressure relief hole 206 to control the opening and closing. The electric paddles are electrically connected to the centralized control device 4 through electric paddle cables. When the automatic regulating valve body 2 is in the upper position of the outer sleeve 208 of the automatic regulating valve, the upper limit pin 202 touches the upper limit top plate 209, and the lower position mark 404 touches the upper position sensor 402 of the automatic regulating valve. The control unit receives a high-pressure state signal. To prevent safety accidents caused by high pressure, the control unit will control the electric paddle through the electric paddle cable to open the pressure relief hole 206. The excess gas in the cold water tank 1 will be discharged through the pressure relief hole 206. The device can be restored from the high-pressure state to the normal state in a short time. When the automatic regulating valve body 2 is in the lower position of the automatic regulating valve external sleeve 208, the lower limit pin 203 touches the lower limit top plate 210, and the upper position mark 401 touches the lower position sensor 405. The control unit receives a low pressure state signal. To prevent safety accidents caused by low pressure, the control unit controls the electric paddle through the electric paddle cable to open the air intake hole 205. The cold water tank 1 balances the pressure inside and outside the cold water tank 1 through the air intake hole 205. To ensure safety, carbon dioxide in the air has to be introduced into the system. This state is a protection measure under extreme conditions.

[0041] The setting of the centralized control device 4, position sensor and position mark realizes the real-time monitoring of the automatic regulating valve position and the opening and closing of 4302, which is convenient for the operator to understand the equipment status in time and improves the management efficiency and the information level of the system.

[0042] The unique advantage of the present invention is that: the device mainly relies on the natural gravity of the automatic regulating valve, and through the cooperation of the ejector pin and the limit top plate, effectively balances the air pressure inside and outside the constant cooling water tank, thereby achieving the goal of energy saving and self-adaptation; at the same time, the device uses an air supply device to further maintain the air pressure and temperature balance inside the constant cooling water tank, increasing the applicable conditions of the device and more complex working conditions; for the automatic regulating valve body 2 running to different states such as high and low positions, the device can compensate for air pressure and temperature through the limit and suction and exhaust functions, and isolate the inside and outside as much as possible to avoid external gas or impurities from entering the box and causing adverse effects.

[0043] The present invention provides a method for using a sealing device for a cooling water tank 1, comprising the following steps: The automatic regulating valve body 2 balances the internal pressure of the cooling water tank 1 by floating up and down. When the air pressure in the cooling water tank 1 is too high, the upper limit pin 202 of the blocking piston 201 touches the upper limit top plate 209 of the cooling water tank 1, and the pressure relief hole 206 discharges the excess air in the cooling water tank 1; after the automatic regulating valve body 2 falls back, according to the degree of falling back, the air supply device is selected to be activated or the counterweight block 207 is adjusted, so that the automatic regulating valve body 2 is in the middle position of the external sleeve 208; When the air pressure in the cooling water tank 1 is too low, the lower limit pin 203 of the sealing piston 201 touches the lower limit top plate 210 of the cooling water tank 1, and the air intake hole 205 sucks air into the cooling water tank 1 to balance the air pressure inside and outside the cooling water tank 1; the air supply device is activated so that the automatic regulating valve body 2 is in the middle position of the external sleeve 208.

[0044] The working principle of a sealing device for a fixed cooling water tank 1 of the present invention is as follows: like Figure 2 As shown, the device is in state 1, i.e., normal state, the automatic regulating valve body 2 is in the middle position of the automatic regulating valve outer sleeve 208, and the internal pressure can be balanced and sealed by the automatic regulating valve body 2 floating up and down, the upper position mark 401 is below the upper position sensor 402, and the lower position mark 404 is above the automatic regulating valve lower position sensor 405; like Figure 2 As shown, the device is in state 2, i.e., low pressure warning state, the automatic regulating valve body 2 is in the middle and lower position of the automatic regulating valve external sleeve 208, the lower position mark 404 touches the lower position sensor 405, and the alarm signal is transmitted to the centralized control device 4; the centralized control device 4 sends out an alarm signal and opens the electric valve 302, and the device can be restored from state 2 (warning state) to state 1 (normal state) in a short time; like Figure 2 As shown, the device is in state 3, i.e., high-pressure state, the automatic regulating valve body 2 is in the upper position of the automatic regulating valve outer sleeve 208, the upper limit ejector pin 202 touches the upper limit top plate 209, to prevent safety accidents caused by high pressure, the excess gas in the cold water tank 1 will be discharged through the pressure relief hole 206, and the device can be restored from state 3 (high-pressure state) to state 1 (normal state) in a short time; the lower position mark 404 touches the upper position sensor 402, and the alarm signal is transmitted to the centralized control device 4; the centralized control device 4 sends an alarm signal and closes the electric valve 302; like Figure 2As shown, the device is in state 4, i.e., a low-pressure state, the automatic regulating valve body 2 is in the lower position of the automatic regulating valve external sleeve 208, the lower limit pin 203 touches the lower limit top plate 210, the upper position mark 401 touches the lower position sensor 405, and the alarm signal is transmitted to the centralized control device 4; the centralized control device 4 sends out an alarm signal and opens the electric valve 302 to supplement with nitrogen. To prevent safety accidents caused by low pressure, the cooling water tank 1 balances the internal and external pressures of the cooling water tank 1 through the air intake hole 205. To ensure safety, carbon dioxide in the air has to be introduced into the system. This state is a protective measure under extreme conditions.

[0045] In the embodiment, the use of electronically controlled equipment is reduced to a minimum, which can reduce costs on the one hand and use mechanical means to ensure the reliability of the device on the other hand; however, the device can introduce a DCS (distributed control system) to monitor and control the operation process of the constant cooling water tank 1, integrate sensor data (such as position, valve opening and closing, etc.) for real-time monitoring and feedback control to improve the information level of the device, realize remote monitoring and fault diagnosis functions, improve the reliability and maintenance efficiency of the system, and maintain the stability of sealing and internal and external pressure balance operation.

[0046] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention. Although the embodiments of the present invention have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A cooling water tank sealing device, characterized in that: The invention comprises an automatic regulating valve body (2) and an air supply device connected to a cooling water tank (1); the automatic regulating valve body (2) comprises a blocking piston (201), an internal sleeve (204), an upper limit ejector pin (202), a lower limit ejector pin (203), an external sleeve (208), an upper limit top plate (209) and a lower limit top plate (210); the external sleeve (208) is connected to the top of the cooling water tank (1); the blocking piston (201) is arranged on the external sleeve (208) ) forms a slidable sealing connection inside, and an upper limit pin (202) and a lower limit pin (203) are provided at both ends of the blocking piston (201), which respectively correspond to the upper limit top plate (209) and the lower limit top plate (210) fixed to the fixed cold water tank (1); the blocking piston (201) is surrounded by an internal sleeve (204); the upper part of the internal sleeve (204) is provided with an air intake hole (205), and the lower part of the internal sleeve (204) is provided with a pressure relief hole (206).

2. A cooling water tank sealing device according to claim 1, characterized in that: A counterweight block (207) is provided on the blocking piston (201).

3. A cooling water tank sealing device according to claim 2, characterized in that: The weight of the counterweight (207) is selected based on the atmospheric pressure exerted on the bottom of the blocking piston (201) and the weight of the automatic regulating valve body (2).

4. A cooling water tank sealing device according to claim 1, characterized in that: The distance between the upper limit top plate (209) and the lower limit top plate (210) is no greater than the sum of the length of the external sleeve (208), the length of the upper limit top pin (202), and the length of the lower limit top pin (203).

5. A cooling water tank sealing device according to claim 1, characterized in that: It also includes a lubricating oil layer; the lubricating oil layer is arranged between the blocking piston (201) and the external sleeve (208) to form a seal.

6. A cooling water tank sealing device according to claim 1, characterized in that: The gas replenishing device comprises a gas storage bottle (3), a replenishing pipeline (301), and an electric valve (302) arranged on the replenishing pipeline (301); the gas storage bottle (3) replenishes gas to the upper part of the inner cavity of the cooling water tank (1) through the replenishing pipeline (301) to fill the gas pressure difference between the inside and outside of the cooling water tank (1).

7. A cooling water tank sealing device according to claim 6, characterized in that: The invention also comprises a centralized control device (4); the centralized control device (4) comprises a signal display and a control unit, an upper position sensor (402), an upper position signal cable (403), a lower position sensor (405), a lower position signal cable (406) and an electric valve detection cable (407); the upper position sensor (402) and the lower position sensor (405) are respectively arranged at the upper edge and the lower edge of the external sleeve (208); the upper position sensor (402) and the lower position sensor (405) transmit signals indicating the position of the automatic regulating valve body (2) to the signal display via the upper position signal cable (403) and the lower position signal cable (406).

8. A cooling water tank sealing device according to claim 7, characterized in that: The electric valve (302) is electrically connected to the signal display via an electric valve detection cable (407).

9. A cooling water tank sealing device according to claim 7, characterized in that: An upper position mark (401) and a lower position mark (404) of the automatic regulating valve are also provided at the upper edge and the lower edge of the inner sleeve (204), respectively. The upper position mark (401) and the lower position mark (404) are used to provide signals to the upper position sensor (402) and the lower position sensor (405) when the automatic regulating valve is shifted.

10. A method for using a cooling water tank sealing device according to any one of claims 1 to 9, characterized in that: The steps include: The automatic regulating valve body (2) balances the internal pressure of the cooling water tank (1) by floating up and down. When the air pressure in the cooling water tank (1) is too high, the upper limit pin (202) of the blocking piston (201) touches the upper limit top plate (209) of the cooling water tank (1), and the pressure relief hole (206) discharges the excess air in the cooling water tank (1); after the automatic regulating valve body (2) falls back, the air supply device is selected to be activated according to the degree of fall back, so that the automatic regulating valve body (2) is in the middle position of the external sleeve (208); When the air pressure in the cooling water tank (1) is too low, the lower limit pin (203) of the blocking piston (201) touches the lower limit top plate (210) of the cooling water tank (1), and the air intake hole (205) draws air into the cooling water tank (1) to balance the air pressure inside and outside the cooling water tank (1); the air supply device is activated so that the automatic regulating valve body (2) is in the middle position of the external sleeve (208).

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