A gas-liquid seal

Abstract

The application relates to a gas-liquid sealing device, belonging to the technical field of lithium battery diaphragm equipment manufacturing. The gas-liquid sealing groove comprises a groove body, a gas cylinder, a baffle and a waste gas treatment mechanism; dichloromethane and liquid water for sealing the dichloromethane are stored in the groove body; a diaphragm inlet is arranged on the upper side of one side of the groove body; a diaphragm outlet is arranged on the upper side of the other side of the groove body; the baffle is arranged on the end face of the diaphragm inlet; the output end of the gas cylinder is connected with the baffle; when the gas cylinder is extended, the baffle encloses the diaphragm inlet into a gap for diaphragm transmission; and the waste gas treatment mechanism is used for recycling the dichloromethane gas evaporated in the groove body. The scheme provided by the application can completely block the dichloromethane leakage through the triple protection mechanism of liquid sealing barrier, controllable gap and waste gas treatment, and ensures the safety of the production environment.

Description

Technical Field

[0001] This application relates to the field of lithium battery separator equipment manufacturing technology, and in particular to a gas-liquid sealing device. Background Technology

[0002] In the wet process of lithium battery separator manufacturing, the extraction process refers to the process of cleaning the separator with organic solvents to form a uniform microporous structure. A liquid-sealing tank is typically installed at the front end of the extraction process. This tank forms a liquid seal layer with a liquid (usually water or low-volatility oil), physically isolating the solvent inside the extraction tank from the external air and preventing the leakage of flammable, explosive, toxic, and harmful volatile gases. However, the separator inlets of existing liquid-sealing tanks are mostly open structures, which cannot prevent the solvent miscible with water from evaporating and escaping through the separator inlet, endangering the health of operators. Utility Model Content

[0003] To overcome the problems existing in related technologies, this utility model provides a gas-liquid sealing device that can completely block dichloromethane leakage through a triple protection mechanism of liquid sealing barrier, controllable gap and waste gas treatment, thus ensuring the safety of the production environment.

[0004] This utility model provides a gas-liquid sealing device for a lithium battery separator washing system, including a tank, a cylinder, a baffle and a waste gas treatment mechanism.

[0005] The tank contains dichloromethane and liquid water that seals the dichloromethane. A diaphragm inlet is located on one side of the tank and a diaphragm outlet is located on the other side. A baffle is located on the end face of the diaphragm inlet. The output end of the cylinder is connected to the baffle. When the cylinder extends, the baffle closes the diaphragm inlet to form a gap that allows the diaphragm to transmit.

[0006] The waste gas treatment unit is used to recover dichloromethane gas evaporated in the tank.

[0007] In some embodiments, the width of the gap is 0.5 to 0.75 cm.

[0008] In some embodiments, the tank is provided with a vertical plate that divides the tank into a left tank and a right tank that are connected to each other. The diaphragm inlet is located on one side of the left tank, the diaphragm outlet is located on one side of the right tank, and the liquid water is located in the left tank.

[0009] In some embodiments, the exhaust gas treatment device includes a variable frequency fan, ductwork, and a chiller;

[0010] The chiller has a liquid storage chamber, which is filled with a condensing medium;

[0011] The top of the tank is provided with ventilation holes, the air inlet of the variable frequency fan is fitted into the ventilation holes, the air outlet is connected to the pipe, one end of the pipe extends into the cooling water in the liquid storage chamber and extends to the liquid surface of the condensing medium.

[0012] The portion of the pipeline immersed in the condensing medium is connected to a liquid storage tank.

[0013] In some embodiments, the portion of the pipe immersed in the condensing medium has a flat structure and is set at an angle of 5 to 15° to the horizontal plane, so that the liquefied dichloromethane gathers into the storage tank, which is connected to the tank body through a solenoid valve.

[0014] In some embodiments, the temperature of the condensing medium is -10 to 5°C.

[0015] In some embodiments, the end of the pipe above the surface of the condensing medium is funnel-shaped and equipped with a filter box containing polystyrene sponge. The bottom of the filter box is equipped with a waste liquid collection tank, which is connected to a waste liquid collection bucket.

[0016] In some embodiments, the liquid storage tank is made of glass.

[0017] In some embodiments, a control system is also included, which includes a programmable logic controller (PLC) and a cylinder controller. The cylinder controller is used to control the extension or retraction of the cylinder. A dichloromethane concentration meter is provided in the tank. The dichloromethane concentration meter is connected to the PLC. The PLC adjusts the output power of the variable frequency fan based on the concentration data from the dichloromethane concentration meter.

[0018] Compared with existing technologies, the advantages of the above-mentioned gas-liquid sealing groove are as follows:

[0019] By utilizing the density difference to form a physical isolation layer, the direct volatilization of dichloromethane is suppressed and the initial gas concentration is reduced.

[0020] By using a cylinder to drive a baffle to form a narrow slit of precise width, the gas leakage path is minimized while ensuring smooth diaphragm transport, thus significantly reducing evaporation loss.

[0021] By utilizing low-temperature condensation combined with adsorption technology, dichloromethane gas volatilized in the tank is captured and liquefied in real time, maintaining a low concentration in the tank and completely blocking the source of leakage. At the same time, the dichloromethane recovered by condensation can be directly reused in the washing process. Attached Figure Description

[0022] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0023] Figure 1 This is a schematic diagram illustrating the structure of a gas-liquid sealing device according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the waste gas treatment mechanism shown in the embodiments of this application.

[0025] Figure label:

[0026] 1. Tank; 2. Cylinder; 3. Baffle; 4. Vertical plate; 5. Variable frequency fan; 6. Pipeline; 7. Chiller; 8. Storage tank; 9. Filter box; 10. Waste liquid collection bucket. Detailed Implementation

[0027] Preferred embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0028] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] While existing sealed tanks can reduce the exposure concentration of dichloromethane to some extent, the open diaphragm inlet allows dichloromethane to continuously escape, harming the workshop environment.

[0031] This utility model provides a gas-liquid sealing device that can solve the environmental problem of dichloromethane escaping into the workshop through a diaphragm inlet by using a triple anti-volatilization design of liquid sealing barrier, dynamically adjustable baffle and waste gas treatment.

[0032] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the structure of a gas-liquid sealing device shown in an embodiment of this application.

[0034] See Figure 1 and Figure 2 This utility model proposes a gas-liquid sealing tank for a wet process production system of lithium battery separators. Its purpose is to prevent dichloromethane (DCM) solvent in the liquid sealing tank from leaking into the workshop. The gas-liquid sealing layer is located at the front end of the extraction tank group. Its diaphragm inlet corresponds to the traction unit of the diaphragm washing system to receive the diaphragm, and the diaphragm outlet is sealed to the extraction tank group. The gas-liquid sealing tank includes a tank body 1, a cylinder 2, a baffle 3, and a waste treatment mechanism.

[0035] The tank 1 is a rectangular shell, welded together from a bottom plate, a top plate, and four side plates. Two side plates, arranged along the direction of the extraction tank assembly, have rectangular notches at their upper parts. These side plates, when welded to the top plate, form a diaphragm inlet and a diaphragm outlet, respectively. The side walls of tank 1 have injection holes for injecting liquid water and dichloromethane. Tank 1 stores dichloromethane and seals the liquid water layer above it, forming the first liquid seal barrier. This liquid seal barrier utilizes the density difference between dichloromethane and water to cause dichloromethane to deposit below the water layer, thereby reducing the initial concentration of dichloromethane in the air within the tank and inhibiting its direct volatilization.

[0036] A vertical plate 4 is installed inside the tank 1, dividing the tank 1 into a left tank 1 and a right tank 1 that are interconnected. The bottoms of the left tank 1 and the right tank 1 are connected. The diaphragm inlet is located on one side of the left tank 1, and the diaphragm outlet is located on the other side of the right tank 1. To ensure that the liquid water can be kept in the left tank 1 and form a liquid seal barrier, dichloromethane is injected into the tank 1 before the liquid water. After the dichloromethane has submerged the vertical plate 4, the liquid water can be injected through the injection hole of the left tank 1.

[0037] By utilizing density differences to form a physical isolation layer, the direct volatilization of dichloromethane is suppressed and the initial gas concentration is reduced. However, simply setting up a liquid seal barrier cannot completely prevent dichloromethane leakage. This is because, under normal temperature conditions, the solubility of dichloromethane in water is approximately 20 g / L, forming an azeotropic mixture with water. The azeotropic point of this mixture is slightly higher than near room temperature. In an uncontrolled temperature environment, the azeotrope continues to volatilize, preferentially releasing dichloromethane during the volatilization process, resulting in a large accumulation of dichloromethane gas inside tank 1. Simultaneously, the diaphragm inlet of the liquid seal tank serves as a channel for diaphragm transmission, meaning the interior of tank 1 is connected to the outside. Therefore, dichloromethane gas inevitably diffuses into the workshop from the diaphragm inlet.

[0038] To solve this problem, a second layer of protection is achieved by setting a baffle 3 and a cylinder 2 on the rectangular notch end face of the diaphragm inlet (i.e., the plane of the notch in the height direction of the tank body 1). Specifically, at least two cylinders 2 are installed and fixed on the tank body 1, with the two cylinders 2 located at opposite ends of the baffle 3, and the output end of the cylinder 2 connected to the baffle 3 to provide transmission accuracy and stability. The cylinder 2 can be controlled by a remote control and / or an automated system to perform telescopic movement, thereby driving it to reciprocate along the height direction of the tank body 1 at the diaphragm inlet end face.

[0039] When cylinder 2 retracts, baffle 3 retracts, and the diaphragm inlet is fully opened, at which point the operator can perform diaphragm insertion.

[0040] When cylinder 2 extends, baffle 3 closes the diaphragm inlet, creating a controllable gap between baffle 3 and the diaphragm inlet end face. The width of this gap is precisely controlled within the range of 0.5–0.75 cm, for example, 0.5 cm, 0.6 cm, 0.65 cm, 0.7 cm, or 0.75 cm. The thickness of lithium battery diaphragms is typically 4–40 μm, and the height change of the diaphragm when wrinkles occur is at the micrometer level. Therefore, within the aforementioned gap width, the diaphragm will not experience jamming during transport.

[0041] In a typical lithium-ion battery separator extraction production system, the equipment is 7.2 meters wide, therefore the length of the separator inlet is approximately 7 meters. This gap size means that the area of ​​the tank 1 with the outside is only 350–525 cm². 2 It is about the size of an A4 sheet of paper. Based on the liquid seal barrier, this gap significantly reduces the evaporation path of dichloromethane gas. Actual measurements show that compared to tank 1, which relies solely on a liquid seal, this controllable gap design reduces dichloromethane leakage by more than 90%.

[0042] However, the concentration of dichloromethane gas accumulated inside tank 1 increases over time, leading to an increase in the amount of dichloromethane leaking from the gap. Therefore, in addition to the liquid seal barrier and controllable gap, a waste gas treatment mechanism is added. This mechanism treats the dichloromethane gas inside tank 1 in real time, ensuring that the dichloromethane concentration inside tank 1 can be maintained at a low level over a long period, thus preventing dichloromethane leakage from the gas-liquid seal tank.

[0043] To solve this problem, a third layer of protection is achieved by setting up an exhaust gas treatment mechanism. Specifically, the exhaust gas treatment mechanism is used to treat the dichloromethane gas volatilized in the tank 1 in real time, maintain a low concentration in the tank, and prevent gas leakage from the controllable gap. The exhaust gas treatment mechanism includes a variable frequency fan 5, a pipeline 6, and a chiller 7.

[0044] The top plate of tank 1 is equipped with ventilation holes. The variable frequency fan 5 is an explosion-proof type, with its air inlet end fitted into the ventilation hole and sealed with a fluororubber sealing strip. The air outlet end of the variable frequency fan 5 is connected to the pipe 6 via a flange, and a fluororubber sealing ring is installed to improve the sealing effect. After the variable frequency fan 5 is started, air enters tank 1 through the gap, while the air containing dichloromethane in tank 1 enters pipe 6 through the ventilation hole and condenses and liquefies in chiller 7. Pipe 6 is fixed to tank 1 by a bracket, and chiller 7 can be installed on top of tank 1. The liquid cooling chamber of chiller 7 is filled with a condensing medium, preferably a mixture of ethanol and water or heat transfer oil. Under the action of chiller 7, the temperature of the condensing medium is maintained in the range of -10℃ to 5℃. One end of pipe 6 extends into the condensing medium in the liquid storage chamber and extends above the liquid surface. The portion of pipe 6 immersed in the condensing medium is connected to the storage tank 8, which is used to collect liquefied dichloromethane. The storage pipe is preferably made of glass so that the liquid level can be observed.

[0045] It is evident that when the variable frequency fan 5 is started, a negative pressure is formed inside the tank 1, and air enters the tank 1 through the gap, which can further prevent the possibility of dichloromethane leaking from the gap.

[0046] Based on the above specific embodiments, to increase the heat exchange area and improve the condensation efficiency of dichloromethane, the pipe 6 immersed in the condensing medium is designed as a flat section, such as a rectangular or corrugated flat shell. This flat structure can be welded to the rest of the pipe 6. The flat section is set at an angle of 5-15° to the horizontal plane to facilitate the flow of liquefied dichloromethane to the storage tank 8 under gravity. An adjustable support is placed inside the liquid cooling chamber, allowing for angle adjustment of the flat section. Furthermore, this flat structure can also be connected to the rest of the pipe 6 via a flexible metal tube.

[0047] Furthermore, the end of pipe 6 located above the condensate surface is funnel-shaped and equipped with a removable filter box 9. The filter box 9 is shaped to fit the funnel opening and has a fluororubber sealing ring on its outer periphery. A polystyrene sponge is placed inside the filter box 9. The polystyrene is used to adsorb residual uncondensed dichloromethane gas. The polystyrene sponge has a porous, interconnected structure with a porosity of 70-80% and an air permeability of 10-20 cm³. 3 / cm 2 Between ·s. The bottom of filter box 9 is equipped with a waste liquid collection tank for collecting waste liquid generated from the dissolution of polystyrene by dichloromethane. This waste liquid can flow into an external waste liquid collection tank 10 through pipe 6. After a period of use, filter box 9 can be disassembled and the polystyrene sponge inside replaced.

[0048] Furthermore, the gas-liquid sealing tank also includes a control system for automated control, comprising a programmable logic controller (PLC) and a cylinder controller. The cylinder controller receives commands and controls the extension / retraction of cylinder 2. A dichloromethane concentration meter is installed in tank 1 and connected to the PLC. Based on real-time data fed back from the concentration meter, the PLC dynamically adjusts the output power of the variable frequency fan 5 to achieve a balance between energy consumption optimization and processing efficiency.

[0049] This invention ensures the sealing performance of the gas-liquid sealing groove through a triple synergistic protection mechanism:

[0050] By utilizing the density difference to form a physical isolation layer, the direct volatilization of dichloromethane is suppressed and the initial gas concentration is reduced.

[0051] The cylinder 2 drives the baffle 3 to form a narrow slit of precise width, which ensures smooth transmission of the diaphragm while minimizing the gas leakage channel and significantly reducing evaporation loss.

[0052] By utilizing low-temperature condensation combined with adsorption technology, dichloromethane gas volatilized in the tank is captured and liquefied in real time, maintaining a low concentration in the tank and completely blocking the source of leakage.

[0053] It is understandable that the specific structure of the gas-liquid sealing groove used for diaphragm transmission and reversal can be referred to the description of the published patent CN211027303U, and will not be repeated here.

[0054] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A gas-liquid sealing device for use in a lithium battery separator washing system, characterized in that, It includes a tank (1), a cylinder (2), a baffle (3), and an exhaust gas treatment mechanism; The tank (1) stores dichloromethane and liquid water containing sealed dichloromethane. A diaphragm inlet is provided on one side of the tank (1), and a diaphragm outlet is provided on the other side. A baffle (3) is provided on the end face of the diaphragm inlet. The output end of the cylinder (2) is connected to the baffle (3). When the cylinder (2) extends, the baffle (3) closes the diaphragm inlet into a gap that allows the diaphragm to transmit. The waste gas treatment mechanism is used to recover the dichloromethane gas evaporated in the tank (1).

2. The gas-liquid sealing device according to claim 1, characterized in that, The width of the gap is 0.5 to 0.75 cm.

3. The gas-liquid sealing device according to claim 1, characterized in that, The tank (1) is provided with a vertical plate (4), which divides the tank (1) into a left tank and a right tank that are connected to each other. The diaphragm inlet is located on one side of the left tank, the diaphragm outlet is located on one side of the right tank, and the liquid water is located in the left tank.

4. The gas-liquid sealing device according to claim 1, characterized in that, The exhaust gas treatment mechanism includes a variable frequency fan (5), a pipeline (6), and a chiller (7); The chiller (7) has a liquid storage chamber containing a condensing medium; The top of the tank (1) is provided with a ventilation hole. The air inlet of the variable frequency fan (5) is fitted into the ventilation hole, and the air outlet is connected to the pipe (6). One end of the pipe (6) extends into the cooling water in the liquid storage chamber and extends to the top of the liquid surface of the condensing medium. The portion of the pipe (6) immersed in the condensing medium is connected to a liquid storage tank (8).

5. The gas-liquid sealing device according to claim 4, characterized in that, The portion of the pipe (6) immersed in the condensing medium has a flat structure and is set at an angle of 5 to 15° with the horizontal plane so that the liquefied dichloromethane gathers into the storage tank (8), which is connected to the tank body (1) through a solenoid valve.

6. The gas-liquid sealing device according to claim 4, characterized in that, The temperature of the condensing medium is -10 to 5°C.

7. The gas-liquid sealing device according to claim 4, characterized in that, The pipe (6) is located above the liquid surface of the condensing medium at the end in a funnel shape and is equipped with a filter box (9). The filter box (9) is filled with polystyrene sponge and the bottom of the filter box (9) is equipped with a waste liquid collection tank, which is connected to a waste liquid collection bucket (10).

8. The gas-liquid sealing device according to claim 4, characterized in that, The liquid storage tank (8) is made of glass.

9. The gas-liquid sealing device according to claim 4, characterized in that, It also includes a control system, which includes a programmable logic controller and a cylinder controller. The cylinder controller is used to control the extension or retraction of the cylinder (2). A dichloromethane concentration meter is provided in the tank (1). The dichloromethane concentration meter is connected to the programmable logic controller. The programmable logic controller adjusts the output power of the variable frequency fan (5) based on the concentration data of the dichloromethane concentration meter.

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