An interference micro-taper seal structure for filter metal filter cartridges

Abstract

The utility model relates to an interference type micro taper surface sealing structure for filter metal filter element, including metal filter element and tube sheet, the outer wall of metal filter element's near end part one side is equipped with boss, a ring annular deformation groove is equipped with in the boss bottom, forms the sealing ring of outward expansion, be equipped with mounting hole on the tube sheet, the bottom inner wall surface of mounting hole is the micro taper surface of with sealing ring transition cooperation, sealing ring is extruded and occurs the elastic deformation when assembling to the micro taper surface, realizes the sealing between metal and metal, the utility model has the advantages of simple structure, reliable sealing, need not gasket, is applicable to high temperature high pressure environment, has remarkable economy and practical value.

Description

Technical Field

[0001] This utility model relates to the field of filtration equipment technology, and in particular to an interference-fit micro-conical sealing structure for metal filter elements, which is suitable for sealing the connection between the metal filter element and the tube sheet in filtration systems of industries such as petroleum, chemical, pharmaceutical, and food. Background Technology

[0002] In filtration equipment, the sealing performance between the metal filter element and the tube sheet directly affects the filtration effect and the reliability of system operation. Filtration systems are widely used in petroleum refining, chemical production, pharmaceutical processes, food processing, and other fields. Their working environments are often characterized by high temperature, high pressure, and corrosive media, which places extremely high demands on the sealing structure.

[0003] Currently, the sealing methods for metal filter elements and tube sheets used both domestically and internationally mainly fall into the following categories:

[0004] Flat gasket sealing structure: This is the most traditional sealing method, using a flange face to fit a gasket for sealing. Gasket materials are typically graphite, spiral wound gaskets, or PTFE. This structure has the following problems: complex installation process requiring precise control of bolt preload; gaskets are prone to aging and creep, requiring regular replacement; sealing performance is unstable under fluctuating temperature conditions; and the gasket material may decompose and contaminate the medium at high temperatures.

[0005] O-ring sealing structure: uses rubber or metal O-rings to achieve sealing, commonly found in low-pressure filtration systems. Disadvantages include: rubber O-rings have limited temperature resistance (generally not exceeding 200℃); metal O-rings have high installation requirements and are prone to damage to the sealing surface; and they are susceptible to "extrusion" failure under pressure fluctuations.

[0006] Welded sealing structure: The filter element is connected to the tube sheet by welding to achieve a permanent seal. Problems: It is not removable; replacing the filter element requires cutting and welding, making maintenance difficult; the heat-affected zone may alter material properties; welding stress exists, which may cause deformation or stress corrosion.

[0007] Threaded sealing structure: A seal is achieved using a threaded connection supplemented with sealant or PTFE tape. Disadvantages: High precision is required for thread machining; the sealant may contaminate the medium; sealing performance deteriorates after repeated disassembly and reassembly.

[0008] Analysis of existing technologies reveals that, despite the existence of various sealing structures, a truly ideal solution that is simple in structure, reliable in sealing, easy to assemble and disassemble, and requires no auxiliary sealing elements is still lacking in high-temperature, high-pressure, and corrosive media environments. This is particularly true in filtration equipment in the chemical and petroleum industries, where traditional sealing structures often become weak points in system reliability. Utility Model Content

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide an interference-fit micro-conical sealing structure for metal filter elements, which solves the problems of complex sealing structures, reliance on gaskets, and poor reliability between metal filter elements and tube sheets in existing technologies. This invention is an interference-fit micro-conical sealing structure that requires no gaskets, has a simple structure, provides reliable sealing, and is suitable for high-temperature and high-pressure environments.

[0010] The above-mentioned utility model objective is achieved through the following technical solution:

[0011] The present invention provides an interference-fit micro-conical sealing structure for a metal filter element, comprising a metal filter element and a tube sheet. A boss is provided on the outer wall of the metal filter element near the end, and an annular deformation groove is provided at the bottom of the boss to form an outwardly expanding sealing ring.

[0012] The tube sheet is provided with mounting holes, and the bottom inner wall surface of the mounting holes is a micro-conical surface that transitions with the sealing ring. During assembly, the sealing ring undergoes elastic deformation due to the compression of the micro-conical surface, thereby achieving a seal between metals.

[0013] According to one embodiment of the present invention, the boss is integrally formed with the metal filter element.

[0014] According to one embodiment of the present invention, the taper of the microconical surface is in the range of 0.5° to 3°.

[0015] According to one embodiment of the present invention, the cross-section of the deformation groove is circular or trapezoidal.

[0016] According to one embodiment of the present invention, the top end of the metal filter element is provided with an external thread, which, when used with a nut, achieves axial compression and fixation to the tube sheet.

[0017] According to one embodiment of the present invention, a washer is provided between the nut and the tube sheet.

[0018] According to one embodiment of the present invention, the interference fit between the sealing ring and the micro-conical surface is 0.05 mm to 0.2 mm.

[0019] According to one embodiment of the present invention, the metal filter element and the tube sheet are made of stainless steel, titanium alloy or nickel-based alloy.

[0020] According to one embodiment of the present invention, a guide chamfer is provided at the entrance of the mounting hole.

[0021] In summary, compared with the prior art, the present invention has at least one of the following beneficial technical effects:

[0022] 1. This utility model discloses an interference-fit micro-conical sealing structure for metal filter elements, comprising a metal filter element and a tube sheet. An integrally formed boss is provided on the outer wall of the metal filter element near its end, and a deformation groove is provided at the bottom of the boss to form a sealing ring; a micro-conical surface is provided at the bottom of the mounting hole of the tube sheet. During assembly, the sealing ring undergoes elastic deformation under the compression of the micro-conical surface, achieving an interference seal between the metal parts. This utility model has a simple structure, reliable sealing, and requires no gaskets, making it suitable for high-temperature and high-pressure environments, and possessing significant economic and practical value.

[0023] 2. This utility model completely eliminates the need for gaskets and their procurement and replacement costs: It employs direct metal-to-metal contact sealing, eliminating the need for any auxiliary sealing elements, thus reducing material and inventory management costs. Simplified structure and convenient assembly: The reduced number of parts and simplified assembly process lowers the skill requirements for operators and improves assembly efficiency. Significantly improved sealing reliability: The metal-to-metal interference fit is suitable for high-temperature, high-pressure, and corrosive media environments, ensuring stable and reliable sealing performance. Excellent self-positioning function: The micro-conical surface structure automatically aligns during assembly, improving assembly accuracy and reducing leakage caused by installation deviations.

[0024] 3. This utility model is easy to maintain and reusable: the filter element can be disassembled and reassembled multiple times without affecting the sealing performance, eliminating the need to replace sealing components and greatly reducing maintenance costs. No pollution risk: complete metal-to-metal contact avoids contamination of the media by the decomposition of non-metallic materials, meeting high cleanliness requirements. Strong adaptability: by adjusting parameters such as taper and interference fit, it can adapt to different working conditions, with a wide range of applications. Long service life: the aging resistance of metallic materials is far superior to that of non-metallic sealing materials, greatly extending the service life. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0026] Figure 2 for Figure 1 A magnified view of part A in the diagram.

[0027] Reference numerals: 1. Metal filter element; 11. Boss; 12. Deformation groove; 13. Sealing ring; 2. Tube sheet; 21. Mounting hole; 22. Micro-conical surface; 3. External thread; 4. Nut; 5. Guide chamfer. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0029] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] Example 1:

[0032] Reference Figure 1 and Figure 2 This invention discloses an interference-fit micro-conical sealing structure for a metal filter element, comprising a metal filter element 1 and a tube sheet 2. The outer wall of the metal filter element 1 near its end is provided with a boss 11, and the bottom of the boss 11 is provided with an annular deformation groove 12 to form an outwardly expanding sealing ring 13. The tube sheet 2 is provided with a mounting hole 21, and the bottom inner wall surface of the mounting hole 21 is a micro-conical surface 22 that transitionally fits with the sealing ring 13. During assembly, the sealing ring 13 is squeezed by the micro-conical surface 22 and undergoes elastic deformation to achieve a metal-to-metal seal.

[0033] The boss 11 is integrally formed with the metal filter element 1. The taper of the micro-conical surface 22 ranges from 0.5° to 3°. The cross-section of the deformation groove 12 is circular or trapezoidal. The top of the metal filter element 1 is provided with an external thread 3, which, together with the nut 4, achieves axial compression and fixes it on the tube sheet 2. A washer is provided between the nut 4 and the tube sheet 2. The interference fit between the sealing ring 13 and the micro-conical surface 22 is 0.05mm to 0.2mm. The metal filter element 1 and the tube sheet 2 are made of stainless steel, titanium alloy, or nickel-based alloy. A guide chamfer 5 is provided at the entrance of the mounting hole 21.

[0034] In this embodiment, the taper of the micro-conical surface 22 is preferably 1°. This small taper design ensures both self-alignment during assembly and sufficient contact stress. The deformation groove 12 has an arc-shaped cross-section. This design gives the sealing ring 13 appropriate elastic deformation capacity, ensuring sealing performance while avoiding damage due to excessive deformation. The interference fit is controlled at approximately 0.1 mm. This interference fit range ensures that the deformation required during assembly is within the material's elastic limit, guaranteeing the reliability and reusability of the seal, ensuring sealing effect without damaging the parts. The structure described in this utility model is suitable for corrosion-resistant metal materials such as stainless steel and titanium alloys, and can be widely used in filtration equipment in chemical, petroleum, and pharmaceutical industries.

[0035] During assembly, insert the metal filter element 1 into the mounting hole 21 until the sealing ring 13 contacts the micro-conical surface 22. Then tighten the nut 4, and the axial clamping force causes the sealing ring 13 to undergo elastic deformation, forming an interference fit with the micro-conical surface 22 to achieve a seal.

[0036] Example 2:

[0037] In this embodiment, the metal filter element 1 of this invention is made of 316 stainless steel, with an outer diameter of 50mm and a wall thickness of 2mm. The boss 11 has an outer diameter of 52mm and a height of 8mm. The deformation groove 12 has an arc-shaped cross-section with a radius of 1mm and a depth of 1.5mm. The sealing ring 13 has a thickness of 3mm.

[0038] The tube sheet 2 is made of 304 stainless steel with a thickness of 40mm. The micro-conical surface 22 of the mounting hole 21 has a taper of 1°, and the inlet is provided with 2×45° guide chamfers 5.

[0039] During assembly, insert the metal filter element 1 into the mounting hole 21 until the sealing ring 13 contacts the micro-conical surface 22. Then tighten the nut 4, and the axial clamping force causes the sealing ring 13 to undergo elastic deformation, forming an interference fit with the micro-conical surface 22, with an interference amount of 0.1 mm.

[0040] Example 3: Implementation methods with different material combinations

[0041] This embodiment has the same structure as Embodiment 2, but the materials are different. For highly corrosive media environments, the metal filter element 1 is made of Hastelloy C-276, and the tube sheet 2 is made of 316L stainless steel. The interference fit between the sealing ring 13 and the micro-conical surface 22 is adjusted to 0.08 mm to balance sealing performance and material strength.

[0042] Example 4: Implementation Method for High-Temperature Environments

[0043] For high-temperature operating conditions (working temperature above 500℃), both the metal filter element 1 and the tube sheet 2 are made of nickel-based alloy Inconel 600. Considering the change in the elastic modulus of the material at high temperatures, the taper of the micro-conical surface 22 is adjusted to 1.5°, and the interference fit is increased to 0.15mm. The deformation groove 12 adopts a trapezoidal cross-section with a depth of 2mm to provide better elastic recovery capability.

[0044] Example 5: Implementation of Large-Diameter Filter Cartridges

[0045] This invention is also applicable to large-diameter metal filter elements 1 with a diameter of 200mm. To ensure uniform sealing, three deformation grooves 12 are evenly arranged in the circumferential direction, forming three independent sealing rings 13. The taper of the micro-conical surface 22 is reduced to 0.8° to reduce the axial force required for assembly. The interference fit is controlled at 0.12mm.

[0046] Processing requirements: To ensure sealing performance, the machining accuracy requirements for key components are as follows: Surface roughness Ra of micro-cone 22 ≤ 0.8 μm; roundness tolerance of sealing ring 13 ≤ 0.05 mm; cone angle tolerance of micro-cone 22 ± 0.1°; perpendicularity of mounting hole 21 to end face of tube sheet 2 ≤ 0.05 mm.

[0047] Assembly process key points: Clean all sealing surfaces before assembly to ensure they are free of dirt and damage; apply a small amount of high-temperature antioxidant (such as nickel-based lubricant) to the surface of the micro-cone 22; use a special installation tool to ensure that the filter element and tube sheet 2 are aligned; tighten the nut 4 evenly according to the torque requirements, the recommended torque is 50-80 N·m; after assembly, perform an airtightness test, the test pressure is 1.5 times the working pressure.

[0048] Technical effectiveness verification:

[0049] To verify the technical effects of this utility model, a series of experimental tests were conducted, including sealing performance tests, life tests, and high temperature and high pressure adaptability tests.

[0050] Sealing performance test: The leakage rate of the sealing structure was detected using a helium mass spectrometer leak detector. The results are shown in Table 1.

[0051] Table 1. Leakage rate test results under different operating conditions

[0052] 0.5 20 <![CDATA[<1×10 -9 ]]> 2.0 20 <![CDATA[<1×10 -9 ]]> 5.0 20 <![CDATA[2.3×10 -9 ]]> 8.0 20 <![CDATA[5.6×10 -9 ]]> 5.0 200 <![CDATA[3.8×10 -9 ]]> 5.0 400 <![CDATA[8.2×10 -9 ]]>

[0053] Test results show that this invention exhibits excellent sealing performance under various working conditions, with a leakage rate far lower than the industry standard requirement of 1×10⁻⁶. -6 mbar·L / s.

[0054] Life test: The sealing structure of this invention underwent 1000 disassembly and assembly cycles, with the sealing performance retested after each disassembly and assembly. After 1000 cycles, the sealing performance remained above 90% of its initial value, demonstrating good durability and reusability.

[0055] High-temperature and high-pressure adaptability test: A continuous test was conducted for 500 hours on a high-temperature and high-pressure testing device at 5 MPa and 400℃. The leakage rate was periodically monitored during the test. The leakage rate remained stable throughout the entire test, without significant changes, proving that this invention is suitable for high-temperature and high-pressure environments.

[0056] Compared with traditional sealing structures:

[0057] The present invention was compared with traditional gasket seals and O-ring seals, and the results are shown in Table 2:

[0058] Table 2 Comparison of performance of different sealing structures

[0059] Maximum operating temperature (°C) 500 200 600 Maximum working pressure (MPa) 10 5 15 Leakage rate (mbar·L / s) <![CDATA[10 -6 ]]> <![CDATA[10 -7 ]]> <![CDATA[10 -9 ]]> Number of disassembly and assembly 5-10 20-30 >1000 Media compatibility medium Difference excellent

[0060] The comparison results show that the present invention is significantly superior to the traditional sealing structure in all performance indicators.

[0061] Industrial application examples:

[0062] This utility model has been successfully applied in multiple industrial fields. The following are two typical application examples:

[0063] Case 1: Petrochemical Hydrogenation Unit: In a petrochemical plant's hydrogenation unit, the reactor outlet filter originally used graphite gaskets for sealing, which resulted in frequent leaks, requiring gasket replacement on average every 3 months. After switching to the interference-fit micro-cone sealing structure of this invention, it has operated continuously for 18 months without leaks, saving approximately 500,000 yuan in maintenance costs.

[0064] Case 2: Aseptic Filtration System in the Pharmaceutical Industry: A pharmaceutical company's aseptic filtration system requires extremely high cleanliness, and traditional sealing structures pose a risk of contamination. After adopting this new invention, not only was the risk of contamination of the pharmaceutical solution by the sealing material completely eliminated, but the filter element replacement time was also reduced from 4 hours to 1 hour, significantly improving production efficiency.

[0065] The implementation principle of this utility model is as follows: This utility model discloses an interference-fit micro-conical sealing structure for metal filter elements, including a metal filter element 1 and a tube sheet 2. An integrally formed boss 11 is provided on the outer wall near the end of the metal filter element 1, and a deformation groove 12 is provided at the bottom of the boss 11 to form a sealing ring 13; a micro-conical surface 22 is provided at the bottom of the mounting hole 21 of the tube sheet 2. During assembly, the sealing ring 13 undergoes elastic deformation under the compression of the micro-conical surface 22, achieving an interference seal between the metals. This utility model has a simple structure, reliable sealing, and requires no gaskets. It is suitable for high-temperature and high-pressure environments and has significant economic and practical value.

[0066] The embodiments described herein are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. An interference-fit micro-conical sealing structure for a metal filter element, comprising a metal filter element (1) and a tube sheet (2), characterized in that: The metal filter element (1) has a boss (11) on the outer wall near the end, and the bottom of the boss (11) has an annular groove (12) to form an outwardly expanding sealing ring (13). The tube sheet (2) is provided with mounting holes (21). The bottom inner wall surface of the mounting hole (21) is a micro-conical surface (22) that transitions with the sealing ring (13). When the sealing ring (13) is assembled, it undergoes elastic deformation due to the compression of the micro-conical surface (22), thereby achieving a seal between metals.

2. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The boss (11) is integrally formed with the metal filter element (1).

3. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The taper of the microconical surface (22) ranges from 0.5° to 3°.

4. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The cross-section of the deformation groove (12) is circular or trapezoidal.

5. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The metal filter element (1) has an external thread (3) at its top end, which, together with a nut (4), achieves axial compression and fixation on the tube sheet (2).

6. The interference-fit micro-conical sealing structure for a metal filter element according to claim 5, characterized in that: A washer is provided between the nut (4) and the tube sheet (2).

7. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The interference fit between the sealing ring (13) and the micro-conical surface (22) is 0.05 mm to 0.2 mm.

8. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The metal filter element (1) and tube sheet (2) are made of stainless steel, titanium alloy or nickel-based alloy.

9. The interference-fit micro-conical sealing structure for a metal filter element according to claim 1, characterized in that: The mounting hole (21) has a guide chamfer (5) at its entrance.

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