A sealing connection structure of a ceramic filter tube and a stainless steel shell

Abstract

The utility model relates to a sealing connection structure technical field, and disclose a kind of sealing connection structure of ceramic filter tube and stainless steel shell, including, joint, select stainless steel material;Gas pipe, and joint between using argon arc welding mode fixed connection, the first recess is provided in the side edge of the gas pipe far from joint, first PTFE gasket is provided in the first recess;Connecting pipe, and the one end of the gas pipe far from the joint using argon arc welding mode fixed connection;Filter core cover, thread connection in the one end of the connecting pipe far from gas pipe, the side edge of the filter core cover towards the connecting pipe is provided with second recess, second PTFE gasket is provided in the second recess;Filter core, two ends are respectively contacted with first PTFE gasket and second PTFE gasket, by the filter core cover is screwed in two times, the filter core is pressed in the filter core cover and gas pipe between.

Description

Technical Field

[0001] This utility model relates to the field of sealing connection structure technology, specifically to a sealing connection structure between a ceramic filter tube and a stainless steel shell. Background Technology

[0002] Currently, ceramic filter tubes are widely used in gas purification, environmental monitoring, and industrial process control due to their high temperature resistance, corrosion resistance, and excellent mechanical strength. Ceramic filter tubes are typically used for filtering solid particles from gases, and are particularly suitable for high-temperature, highly corrosive, or high-pressure conditions. However, in practical applications, ceramic filter tubes need to be reliably connected to a metal housing (such as a stainless steel housing) to ensure the sealing of the gas flow path and the mechanical stability of the device. In existing technologies, the connection between ceramic filter tubes and stainless steel housings often involves mechanical pressing, single tightening, or direct welding of metal components followed by sealing with a hard sealing ring. While these structures are relatively simple to manufacture, they are susceptible to vibration, thermal expansion differences, and assembly stress relaxation during long-term operation, leading to loosening or leakage of the sealing surface. This is especially true under high-frequency vibration or temperature cycling environments, where the sealing reliability significantly decreases. Furthermore, the brittle nature of ceramic filter tubes makes them prone to stress concentration due to rigid contact during connection, which can lead to breakage and shorten their service life.

[0003] To improve the reliability of sealed connections, some technical solutions introduce flexible sealing gaskets, such as PTFE (polytetrafluoroethylene) material, which utilizes its good chemical corrosion resistance and certain deformation ability to buffer contact stress.

[0004] In view of the above, this application proposes a sealing connection structure between a ceramic filter tube and a stainless steel shell to solve the above problems. The structure optimizes the material selection, structural design and assembly process to ensure the absolute sealing of the gas flow path and avoid excessive mechanical stress on the ceramic filter tube. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a sealed connection structure between a ceramic filter tube and a stainless steel shell, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A sealing connection structure between a ceramic filter tube and a stainless steel housing, comprising:

[0008] The connector is made of stainless steel.

[0009] The gas inlet pipe is fixedly connected to the connector by argon arc welding. The gas inlet pipe has a first groove on the edge away from the connector, and a first PTFE gasket is placed in the first groove.

[0010] The connecting pipe is fixedly connected to the end of the gas inlet pipe away from the joint by argon arc welding.

[0011] The filter element cover is threaded to the end of the connecting pipe away from the air inlet pipe. A second groove is provided on one side edge of the filter element cover facing the connecting pipe, and a second PTFE gasket is provided in the second groove.

[0012] The filter element has two ends that are in contact with the first PTFE gasket and the second PTFE gasket, respectively. The filter element is pressed between the filter element cover and the connecting pipe by tightening the filter element cover in two stages.

[0013] Optionally, the inner and outer diameters of the first PTFE gasket and the second PTFE gasket match the inner and outer diameters of the filter element, and the thickness of the first PTFE gasket and the second PTFE gasket is 1mm, with an allowable tolerance of ±0.1mm.

[0014] Optionally, the end face of the filter element is polished, and the smoothness of the polished surface Ra is ≤ 0.8 μm.

[0015] Optionally, there is a 0.1mm gap between the filter element and the filter element cover.

[0016] This utility model provides a sealed connection structure between a ceramic filter tube and a stainless steel shell, which has the following advantages:

[0017] 1. By using a combination of "double tightening + PTFE gasket", the initial pre-tightening is used to position the component, and the secondary pre-tightening, combined with the creep characteristics of the PTFE gasket, ensures that the sealing surface is fully fitted, effectively preventing gas leakage around the filter element. The sealing reliability is improved by more than 50% compared with the traditional mechanical pressing method.

[0018] 2. The pre-tightening force and the damping characteristics of the PTFE gasket work together to effectively absorb micro-vibrations during operation, suppress loosening of connecting parts, and prolong the sealing time. It is suitable for working conditions with strong vibration or frequent start-stop. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] In the diagram: 1. Connector; 2. Air inlet pipe; 21. First groove; 22. First PTFE gasket; 3. Connecting pipe; 4. Filter cover; 41. Second groove; 42. Second PTFE gasket; 5. Filter element. Detailed Implementation

[0021] In order to make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0022] In the description of this utility model, it should be understood that the terms "lateral", "longitudinal", "end", "edge", "sidewall", "upper", "lower", "upper part", "lower part", "directly above", "surface", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "end", "head", "tail", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] This application proposes a sealing connection structure between a ceramic filter tube and a stainless steel shell, as detailed below:

[0024] For reference Figure 1 This application is mainly composed of a connector 1, an air inlet pipe 2, a connecting pipe 3, a filter element cover 4, and a filter element 5. By using the pre-tightening force of the two tightenings in combination with the damping characteristics of the PTFE gasket, the structural loosening caused by vibration is suppressed, which can improve the reliability by more than 50% compared with the pure mechanical pressing method.

[0025] For reference Figure 1 The connector 1, the air inlet pipe 2, the connecting pipe 3, the first PTFE gasket 22 and the second PTFE gasket 42 are all made of stainless steel, forming the stainless steel object of the structure of this application.

[0026] Furthermore, the material of connector 1 is preferably a cold-drawn 316L stainless steel bar. The VCR spherical surface of connector 1 is precision machined with a surface roughness Ra of less than 0.2μm to ensure good sealing performance. The Brinell hardness (HB) of the material used is not less than 220 to ensure the mechanical strength and wear resistance of connector 1.

[0027] Furthermore, the connecting pipe 3 is preferably made of 316L stainless steel, and its outer surface is machined with threads conforming to the 1 / 4-20UNC specification; at the same time, the surface of the connecting pipe 3 is provided with multiple round holes for gas to flow through.

[0028] For reference Figure 1 The gas inlet pipe 2 and the connector 1 are fixedly connected by argon arc welding. The connecting pipe 3 is fixedly connected to the end of the gas inlet pipe 2 away from the connector 1 by argon arc welding. The connector 1, the gas inlet pipe 2 and the connecting pipe 3 are all fixedly connected by argon arc welding. This welding method can form a strong and sealed connection structure, effectively avoid gas leakage, improve the mechanical strength and stability of the overall device, and at the same time, due to argon protection, the weld quality is high, and oxidation and contamination during the welding process are prevented, thereby ensuring the long-term reliable operation of the equipment.

[0029] For reference Figure 1 The end of the connecting pipe 3 furthest from the air inlet pipe 2 is threaded with a filter element cover 4. The filter element 5 is securely fixed between the filter element cover 4 and the connecting pipe 3 by tightening the filter element cover 4 and the connecting pipe 3 twice, which can prevent the filter element 5 from shifting or loosening in a vibrating working environment. The tightening work between the filter element cover 4 and the connecting pipe 3 is divided into two parts. First, an initial pre-tightening torque of 20 N·m is applied to the fastener to achieve the initial fixation of the component. Then, the pre-tightening torque is increased to 40 N·m and held for 30 seconds to allow the PTFE gasket to creep and deform, ensuring that the sealing surface is fully fitted, thereby improving the sealing performance and the reliability of the connection.

[0030] For reference Figure 1 The filter element 5 is a tubular porous ceramic filter tube made of alumina (Al2O3), and its gas permeation flow rate is not less than 90 slpm (standard liters / minute). At the same time, the end face of the filter element 5 is polished, and the smoothness of the polished surface Ra≤0.8μm. There is a gap of 0.1mm between the filter element 5 and the filter element cover 4 to avoid rigid contact.

[0031] For reference Figure 1 To further achieve efficient sealing, protect the ceramic filter element, and improve the durability and ease of maintenance of the device, a PTFE gasket is provided; a second groove 41 is provided on the edge of the filter element cover 4 facing the connecting pipe 3, and a second PTFE gasket 42 is provided in the second groove 41; a first groove 21 is provided on the edge of the air inlet pipe 2 away from the connector 1, and a first PTFE gasket 22 is provided in the first groove 21; when the filter element 5 is connected, both ends are pressed against the first PTFE gasket 22 and the second PTFE gasket 42.

[0032] Furthermore, the inner and outer diameters of the first PTFE gasket 22 and the second PTFE gasket 42 match the inner and outer diameters of the filter element 5, and the thickness of both the first PTFE gasket 22 and the second PTFE gasket 42 is 1mm, with an allowable deviation of ±0.1mm; the sealing effect is optimal when the compression rate is 20%.

[0033] In this invention, the working steps of the device are as follows:

[0034] 1. First, use ultrasonic cleaning to clean the connector 1, air inlet pipe 2, connecting pipe 3, first PTFE gasket 22 and second PTFE gasket 42, and wipe the filter element 5 with alcohol;

[0035] 2. Next, the connector 1, the gas inlet pipe 2, and the connecting pipe 3 are fixedly connected by argon arc welding;

[0036] 3. Then, apply silicone grease to one side of the first PTFE gasket 22 and the second PTFE gasket 42, and place them with the grease-coated side facing into the first groove 21 and the second groove 41;

[0037] 4. Finally, place the first PTFE gasket 22 and the second PTFE gasket 42 on both sides of the filter element 5, and then tighten the filter element 5 by two tightening operations.

[0038] Gas enters the device through one end of connector 1 and flows through the internal channel of the gas inlet pipe 2 to the location of filter element 5. During the flow, the gas enters filter element 5 through the round holes on the wall of connecting pipe 3. The round holes initially trap some solid contaminants while introducing the gas. Subsequently, the gas is further filtered by the porous structure of filter element 5 to remove residual impurities. The first PTFE gasket 22 and the second PTFE gasket 42 limit the gas flow path and prevent leakage around the gaps around filter element 5, thereby ensuring that the gas completely passes through the filtration process of filter element 5.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of this utility model. All such changes and modifications fall within the scope of protection claimed by this utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A sealing connection structure between a ceramic filter tube and a stainless steel shell, characterized in that: include, Connector (1) is made of stainless steel; The gas inlet pipe (2) is fixedly connected to the connector (1) by argon arc welding. The gas inlet pipe (2) has a first groove (21) on the edge away from the connector (1), and a first PTFE gasket (22) is provided in the first groove (21). The connecting pipe (3) is fixedly connected to the end of the gas inlet pipe (2) away from the joint (1) by argon arc welding; The filter element cover (4) is threaded to the end of the connecting pipe (3) away from the air inlet pipe (2). The filter element cover (4) has a second groove (41) on one side edge facing the connecting pipe (3). A second PTFE gasket (42) is provided in the second groove (41). The filter element (5) is in contact with the first PTFE gasket (22) and the second PTFE gasket (42) at both ends respectively. The filter element (5) is pressed between the filter element cover (4) and the connecting pipe (3) by tightening the filter element cover (4) in two stages.

2. The sealing connection structure between the ceramic filter tube and the stainless steel shell according to claim 1, characterized in that: The inner and outer diameters of the first PTFE gasket (22) and the second PTFE gasket (42) match the inner and outer diameters of the filter element (5). The thickness of the first PTFE gasket (22) and the second PTFE gasket (42) is 1 mm, and the allowable tolerance is ±0.1 mm.

3. The sealing connection structure between the ceramic filter tube and the stainless steel shell according to claim 1, characterized in that: The end face of the filter element (5) is polished, and the smoothness of the polished surface Ra is ≤0.8μm.

4. The sealing connection structure between the ceramic filter tube and the stainless steel shell according to claim 1, characterized in that: There is a 0.1mm gap between the filter element (5) and the filter element cover (4).

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