Dead space free connection sealing device for FEP hoses

Abstract

The application relates to the technical field of fluid pipeline connection, in particular to a dead-angle-free connection sealing device for FEP hoses, which comprises a pipe connector and a locking nut. The inner wall of the plug-in part of the pipe connector is provided with a smooth transition guide cone surface, so that the step dead angle at the connection position is eliminated; the outer wall is provided with an outer sealing cone surface and a barb structure. The inner wall of the locking nut is provided with an inner pressing cone surface matched with the outer sealing cone surface. When the locking nut is screwed, the cone surface matching presses the hose wall radially to realize sealing, and the barb structure provides anti-pulling force. The pipeline cut-off end surface on the connector provides physical limiting for the hose and the nut, so that the installation precision and protection of the hose are ensured. The device realizes smoothness and dead-angle-freeness inside the connection position, reliable sealing and no damage to the hose in the installation process.

Description

Technical Field

[0001] This application relates to the field of fluid pipeline connection technology, and in particular to a dead-angle-free connection sealing device for FEP hoses. Background Technology

[0002] In industries with high cleanliness requirements, such as automotive painting, biopharmaceuticals, and semiconductor manufacturing, FEP hoses are widely used due to their excellent chemical stability and smooth inner walls. To ensure the purity of the production process, piping systems are typically cleaned quickly using physical methods such as cleaning balls throughout the entire pipeline.

[0003] Existing hose connection solutions, such as traditional barbed fittings or some simple crimp fittings, often create hard-to-clean dead corners between the hose end face and the fitting body, failing to meet the requirements of high-cleanliness applications. While some flared fittings aim to solve the dead corner problem, their sealing and locking mechanisms for the hose are often inadequate. Especially for materials like FEP that are sensitive to compressive stress, excessive compression during installation can easily lead to plastic deformation or fatigue cracking of the hose, causing leakage risks; while insufficient compression force cannot provide sufficient sealing performance and pull-out resistance.

[0004] Based on the above, this application proposes a dead-angle-free connection sealing device for FEP hoses, which can effectively solve the above problems. Utility Model Content

[0005] To address the problem in existing technologies that it is difficult to simultaneously achieve a seamless connection at the joint and a reliable, non-destructive connection to the FEP hose, this application proposes a seamless connection sealing device for FEP hoses.

[0006] A dead-angle-free connection sealing device for FEP hoses, comprising: A pipe connector includes a connector body and a plug-in portion extending from the connector body. The connector body has a threaded portion, and a pipe stop face is provided at the junction of the connector body and the plug-in portion for the end face of an FEP flexible hose to abut against. A locking nut, threaded to the connector body, is used to press the FEP hose onto the connector; wherein, at the port of the insertion part away from the connector body, an outwardly expanding guide cone surface is provided, the guide cone surface being configured to smoothly connect the FEP hose to the inner hole of the insertion part.

[0007] This structure creates a continuous and seamless transition between the inner bore of the connector and the inner bore of the hose, which helps eliminate unsanitary dead spots such as gaps and steps commonly found in the flow path, reducing the risk of fluid media residue and bacterial growth.

[0008] In one embodiment, an outer sealing cone surface is formed on the outer peripheral surface of the insertion portion, and an inner pressing cone surface is formed on the inner wall of the locking nut. The inner pressing cone surface and the outer sealing cone surface are configured to clamp and press the wall of the FEP hose from the outside when the locking nut is tightened. Through the cooperation of the cone surfaces, the axial locking force of the locking nut can be converted into a radial pressure evenly distributed in the circumferential direction of the hose wall, which improves the reliability of the seal compared to point contact or line contact sealing methods.

[0009] In one embodiment, the outer sealing cone extends axially along the side near the connector body to form an outer cylindrical surface, and the inner clamping cone also extends axially to form a corresponding inner clamping cylindrical surface. This inner clamping cylindrical surface is configured to gather and shape the FEP hose, which has been radially expanded by the outer sealing cone, into a cylindrical shape. This two-stage design of "cone expansion and cylindrical convergence" ensures that while the hose withstands radial sealing pressure, its tail is constrained within a defined cylindrical space. This helps resist sealing stress relaxation caused by creep, enhancing the long-term mechanical stability and sealing durability of the connection.

[0010] In one embodiment, the end diameter at the junction of the outer sealing conical surface and the outer cylindrical surface is larger than the diameter of the outer cylindrical surface, and the junction forms a radial barb structure. This barb structure can mechanically lock the hose at a small embedment depth on the outer surface of the hose when the hose wall is compressed, thereby providing significant axial pull-out resistance. This design effectively prevents the hose from accidentally slipping out under internal pressure fluctuations or external dragging forces without seriously damaging the hose.

[0011] In one embodiment, the connector body is symmetrically provided with bosses along the axial direction. These bosses are located between the threaded portion and the insertion portion, and the upper surface of the bosses near the insertion portion serves as the pipe's shut-off end face. This boss structure not only provides a clear physical positioning reference for hose insertion, ensuring a constant positional relationship between the hose and the connector during each installation, but also provides a mechanical limiting surface for tightening the locking nut. This position-dependent rather than torque-dependent installation method avoids over-tightening or over-loosening issues caused by differences in operator feel, improving installation accuracy and repeatability.

[0012] In one embodiment, the locking nut includes, along the axial direction, a first locking portion and a second locking portion, the diameter of the second locking portion being larger than that of the first locking portion. The second locking portion further includes, along the axial direction, a receiving groove and a threaded connection groove. The boss mates with the receiving groove, and the threaded connection groove mates with the threaded portion. This structural design defines the internal functional partitions of the locking nut. The mating of the receiving groove and the boss forms the specific structural basis for achieving the aforementioned mechanical limiting and position control functions, ensuring that the final compression deformation of the hose is predetermined by the geometric dimensions of the parts.

[0013] In one embodiment, the inner clamping conical surface and the inner clamping cylindrical surface form a smooth transition connection. This smooth transition design replaces sharp edges with a curved surface, allowing the compressed outer wall of the hose to smoothly slide and enter the shaping area during the tightening of the locking nut. This avoids damage to the outer surface of the hose caused by scratching or cutting during installation, thus protecting the structural integrity of the hose.

[0014] In one embodiment, a protective chamfer is provided at the junction of the receiving groove and the first locking part. This protective chamfer eliminates a potential stress concentration point inside the locking nut. For the hose outer wall that is statically abutting against the pipe end face after installation, this chamfer provides a gentle contact surface, which helps to prevent the hose outer wall from being cut by sharp edges or developing fatigue cracks due to long-term pressure or equipment vibration, thereby improving the long-term safety and service life of the device.

[0015] In one embodiment, the outwardly expanding guide cone is also configured to guide a cleaning ball for pipeline cleaning unimpeded into the FEP hose from the inner hole of the connector. This design ensures smooth passage of physical cleaning tools, meeting the needs of rapid and effective online cleaning of pipeline systems in high-cleanliness applications, and helps to shorten cleaning time and reduce cleaning agent usage.

[0016] In one embodiment, a sealing groove is further provided on the main body of the connector, located on the end face of the connector body away from the locking nut. This sealing groove is used to accommodate a standard seal, achieving a reliable planar seal between the device and external equipment such as a valve block.

[0017] This application provides a dead-angle-free connection sealing device for FEP hoses, which achieves the following technical effects: 1. By setting an internal guide cone surface, a smooth transition between the inner hole of the connector and the inner hole of the hose is achieved, eliminating sanitary dead corners, ensuring fluid purity, and allowing tools such as cleaning balls to pass through unimpeded.

[0018] 2. By adopting a two-stage sealing structure of "conical surface compression + cylindrical surface shaping", combined with the smooth transition of the inner wall and protective chamfer, it not only ensures good sealing performance and pull-out resistance, but also achieves full-process hose protection from installation to long-term use.

[0019] 3. By setting up bosses as dual physical limits for hose insertion and nut tightening, the installation result is transformed from relying on the operator's torque feel to position control determined by mechanical dimensions, ensuring installation accuracy every time. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the overall structure of a dead-angle-free connection and sealing device for FEP hoses proposed in this application.

[0021] Figure 2 This is a schematic cross-sectional view of an FEP hose sealing device with no dead angle proposed in this application.

[0022] Figure 3 This is a cross-sectional schematic diagram of the pipe connector in a dead-angle-free connection sealing device for FEP hoses proposed in this application.

[0023] Figure 4 This is a cross-sectional schematic diagram of the locking nut in a dead-angle-free connection sealing device for FEP hoses proposed in this application.

[0024] Figure 5 This is a schematic diagram of the bolt hole positions in a dead-angle-free connection sealing device for FEP hoses proposed in this application.

[0025] Explanation of reference numerals in the attached figures: 1. Pipe connector; 11. Connector body; 111. Threaded part; 112. Boss; 113. Sealing groove; 12. Insertion part; 121. Guide cone surface; 122. Outer sealing cone surface; 123. Outer cylindrical surface; 13. Pipe end face; 2. Locking nut; 21. Inner pressing cone surface; 22. Inner pressing cylindrical surface; 23. First locking part; 24. Second locking part; 241. Receiving groove; 242. Threaded connection groove; 25. Protective chamfer; 3. FEP hose; 4. Barb structure; 5. Bolt hole position. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-5 This application provides a more detailed description of a dead-angle-free connection and sealing device for FEP hoses.

[0027] This application discloses a seamless connection and sealing device for FEP hoses, including a pipe connector 1 and a locking nut 2, for connecting and sealing FEP hoses 3.

[0028] In this embodiment, the pipe connector 1 can be made of corrosion-resistant and high-cleanliness materials such as stainless steel, PEEK, or PVDF. In this embodiment, stainless steel is preferred as the material. The pipe connector 1 integrally includes a connector body 11 and a plug portion 12 extending forward from the connector body 11.

[0029] Specifically, the connector body 11 is the main body of the device. A threaded portion 111 is provided on the outer circumferential surface of the connector body 11 for threaded connection with the locking nut 2. A sealing groove 113 for installing an O-ring is provided on the end face of the connector body 11 away from the insertion portion 12, to achieve a planar seal between the device and external equipment such as a valve block. Multiple bolt holes 5 are also provided on this end face for fixing the device to external equipment using bolts.

[0030] Specifically, the connector 12 is the part that directly interacts with the FEP hose 3. In the inner bore of the connector 12, at its port furthest from the connector body 11, there is an outwardly expanding, flared guide cone 121. The angle of this guide cone 121 is optimized to smoothly connect with the inner bore of the FEP hose 3, forming a continuous, stepless internal flow path. This design not only eliminates the fluid dead zones common in traditional connectors, preventing media residue and bacterial growth, but also guides cleaning balls used for pipeline cleaning smoothly, meeting the requirements of online cleaning.

[0031] More specifically, the exterior of the insertion portion 12 forms a multi-segment sealing and locking structure. From the end of the insertion portion 12 away from the connector body 11 towards the end closer to the connector body 11, a guiding outer sealing conical surface 122 and an outer cylindrical surface 123 are sequentially formed. The outer sealing conical surface 122 mates with the inner wall of the locking nut 2, applying the main radial sealing pressure to the wall of the FEP hose 3. At the junction of the outer sealing conical surface 122 and the outer cylindrical surface 123, the diameter of one side of the outer sealing conical surface 122 is larger than the diameter of the outer cylindrical surface 123, naturally forming a step, which constitutes the barb structure 4. When the hose is compressed, the barb structure 4 slightly embeds into the outer wall of the hose, providing strong axial pull-out resistance. In this embodiment, the radial inclination angle α of the barb structure 4 is preferably 5°, its maximum radial width is preferably 0.5 mm, and its radial cross-section at the end is preferably trapezoidal.

[0032] More specifically, at the junction of the connector body 11 and the insertion part 12, a radially outward protruding boss 112 is integrally formed. The upper surface of this boss 112 near the insertion part 12 forms the pipeline stop face 13. This pipeline stop face 13 has a dual function: first, it serves as a physical stop when the FEP hose 3 is inserted, ensuring accurate hose insertion depth; second, it serves as a mechanical limiting surface when the locking nut 2 is tightened to the correct position, enabling precise positional control of the hose compression.

[0033] In this embodiment, the internal structure of the locking nut 2 is precisely fitted with the pipe connector 1. The outer peripheral surface of the second locking part (24) is set as an external hexagonal structure, which facilitates tightening operation using a standard wrench. The locking nut 2 can be divided into a first locking part 23 at the front end and a second locking part 24 at the rear end according to its external shape.

[0034] Specifically, a threaded connection groove 242 and a receiving groove 241 are provided inside the second locking part 24. The threaded connection groove 242 is threadedly engaged with the threaded part 111 of the pipe connector 1. The receiving groove 241 is used to receive the boss 112 on the pipe connector 1 when locked in place.

[0035] Specifically, inside the first locking part 23, an inner clamping conical surface 21 and an inner clamping cylindrical surface 22 are sequentially arranged from the front end to the rear end. The inner clamping conical surface 21 corresponds to the outer sealing conical surface 122 on the pipe connector 1, together clamping and pressing the FEP hose 3. The inner clamping cylindrical surface 22 corresponds to the outer cylindrical surface 123, together binding the radially expanding FEP hose 3 and reshaping it into a cylindrical hose. The inner clamping conical surface 21 and the inner clamping cylindrical surface 22 have a smooth transition connection to ensure that the outer wall of the hose will not be scratched during tightening.

[0036] In this embodiment, a protective chamfer 25 is provided at the connection between the receiving groove 241 and the first locking part 23, i.e., the rear end of the inner pressing cylindrical surface 22. If the inner corner of this connection is a 90-degree right angle, after the hose is installed in place, the outer wall of the hose, which is in close contact with the pipe stop end face 13, will be very close to this right angle. Under long-term pressure and slight vibration, this right angle will damage the outer wall of the hose. The protective chamfer 25 can eliminate this hidden danger, protect the hose in a static state, and thus significantly improve the long-term reliability of the connection.

[0037] In this embodiment, the wall thickness t of the FEP hose 3 is preferably 2.5 mm. Based on material properties, the elastic deformation of the FEP hose 3 needs to be controlled between 20% and 30% of its original wall thickness to ensure a good seal and avoid plastic damage. For an FEP hose 3 with a wall thickness of 2.5 mm, the optimal radial compression deformation Δt range for the FEP hose 3 can be calculated to be between 0.5 mm and 0.75 mm based on 2.5 mm × 20% and 2.5 mm × 30%. The radial compression deformation is achieved by the radial gap formed by the inner compression cone surface 21 and the outer sealing cone surface 122 when the pipe connector 1 and the locking nut 2 are fully locked until their pipe end faces 13 are in rigid contact. To ensure that the final hose wall thickness (t-Δt) falls within a safe and effective range, this radial gap needs to be machined between 1.75 mm and 2.0 mm.

[0038] Furthermore, according to the formulas of mechanics of materials By substituting typical parameters of FEP material (elastic modulus E≈600MPa, correction factor K≈1.3), it can be estimated that this device can stably generate an equivalent radial clamping force of 92MPa to 138MPa on the hose wall. This pressure value far exceeds the conventional pipeline fluid pressure of 1.5MPa, theoretically proving that this design can provide a highly reliable seal and effectively resist pressure fluctuations.

[0039] Furthermore, since the radial inclination angle α of the barb structure 4 is preferably 5° and its maximum radial width is preferably 0.5 mm, the optimal radial compression deformation Δt of the FEP hose 3 is between 0.5 mm and 0.75 mm. It can be seen that the bite depth of the barb structure 4 is within the reasonable range of 20% to 30% elastic deformation of the FEP material.

[0040] This quantitative analysis process fully demonstrates that the design of this device is not a simple combination of mechanical structures, but a precise design based on the principles of materials science and engineering mechanics, which transforms the complex problem of sealing force control into a stable, reliable and easy-to-manufacture geometric tolerance problem.

[0041] The working principle of the dead-angle-free connection sealing device for FEP hoses provided in this application embodiment is as follows: First, insert the locking nut 2 onto the FEP hose 3 in the correct orientation. Depending on the hose wall thickness, use a special flaring tool to slightly flare the end of the FEP hose 3 to facilitate subsequent insertion. Push the FEP hose 3 along the insertion part 12 until its end face is fully and evenly abutted against the pipe stop end face 13. At this point, the hose has achieved precise axial positioning. Push the locking nut 2 forward and tighten its outer hexagonal structure with a wrench. During tightening, the inner clamping cone surface 21 first acts on the hose, radially pressing it against the outer sealing cone surface 122 to form a main seal; as tightening continues, the expanded hose portion is guided by the smoothly transitioning inner wall, entering between the inner clamping cylindrical surface 22 and the outer cylindrical surface 123 where it is constricted and shaped, while the barbed structure 4 provides a locking effect. Finally, when the upper end face of the inner receiving groove 241 of the locking nut 2 is fully abutted against the pipe stop end face 13, significant resistance will be felt, and it cannot be screwed in any further. At this point, the installation process is complete.

[0042] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dead-angle-free connection sealing device for FEP hoses, characterized in that, include: A pipe connector (1) includes a connector body (11) and a plug portion (12) extending from the connector body (11). The connector body (11) has a threaded portion (111), and a pipe stop face (13) for the end face of an FEP flexible hose (3) to abut against is provided at the junction of the connector body (11) and the plug portion (12). A locking nut (2) is threaded to the connector body (11) and is used to press the FEP hose (3) onto the pipe connector (1); Wherein, at the port of the inner hole of the plug part (12) away from the connector body (11), there is an outwardly expanding guide cone surface (121), the guide cone surface (121) is configured to smoothly connect the FEP hose (3) and the inner hole of the plug part (12).

2. The dead-angle-free connection sealing device for FEP hoses according to claim 1, characterized in that, An outer sealing cone surface (122) is formed on the outer peripheral surface of the plug part (12), and an inner pressing cone surface (21) is formed on the inner wall of the locking nut (2). The inner pressing cone surface (21) and the outer sealing cone surface (122) are configured to clamp and press the wall of the FEP hose (3) from the outside when the locking nut (2) is tightened.

3. The dead-angle-free connection sealing device for FEP hoses according to claim 2, characterized in that, The outer sealing cone (122) extends axially along the side close to the connector body (11) to form an outer cylindrical surface (123), and the inner pressing cone (21) also extends axially to form an inner pressing cylindrical surface (22). The inner pressing cylindrical surface (22) is configured to gather and shape the FEP hose (3) after it has been radially expanded by the outer sealing cone (122) into a cylindrical shape.

4. The dead-angle-free connection sealing device for FEP hoses according to claim 3, characterized in that, The end diameter of the junction between the outer sealing cone surface (122) and the outer cylindrical surface (123) is larger than the diameter of the outer cylindrical surface (123), and a radial barb structure (4) is formed at the junction of the two.

5. A dead-angle-free connection sealing device for FEP hoses according to claim 3, characterized in that, The inner pressing conical surface (21) and the inner pressing cylindrical surface (22) are connected by a smooth transition.

6. A dead-angle-free connection sealing device for FEP hoses according to claim 1, characterized in that, The connector body (11) is symmetrically provided with bosses (112) along the axial direction. The bosses (112) are located between the threaded part (111) and the plug part (12). The upper surface of the bosses (112) near the plug part (12) is the pipeline cut-off end face (13).

7. A dead-angle-free connection sealing device for FEP hoses according to claim 6, characterized in that, The locking nut (2) includes a first locking part (23) and a second locking part (24) in sequence along the axial direction. The diameter of the second locking part (24) is larger than that of the first locking part (23). The second locking part (24) includes a receiving groove (241) and a threaded connection groove (242) in sequence along the axial direction. The boss (112) cooperates with the receiving groove (241), and the threaded connection groove (242) cooperates with the threaded part (111).

8. A dead-angle-free connection sealing device for FEP hoses according to claim 7, characterized in that, A protective chamfer (25) is provided at the connection between the receiving groove (241) and the first locking part (23).

9. A dead-angle-free connection sealing device for FEP hoses according to claim 1, characterized in that, The outwardly expanding guide cone (121) is also configured to guide a cleaning ball for pipeline cleaning into the FEP hose (3) unimpeded from the inner hole of the connector (12).

10. A dead-angle-free connection sealing device for FEP hoses according to claim 1, characterized in that, A sealing groove (113) is also provided on the main body (11) of the connector, and the sealing groove (113) is provided on the end face of the main body (11) away from the locking nut (2).

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