Method for joining TPE pipes
By using the TPE sleeve and compression member during the TPE pipe joint process, radial force and heating are applied to fuse the first and second pipes with the sleeve, the problems of contamination and leakage during jointing in the prior art are solved, and a high-quality joint effect is achieved.
Patent Information
- Application Number
- CN202380028234.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-03-15
- Filing Date
- 2023-03-14
- Publication Date
- 2025-03-07
AI Technical Summary
The prior art is prone to contamination and leakage when bonding TPE pipes, and the welding process is limited by material compatibility, cycle time, and the quality is poor.
By making the end face of the first TPE tube against the end face of the second TPE tube, a TPE sleeve is provided so as to overlap the end face, a compression member (such as a heat shrink tube) is provided around the sleeve to apply radial force, and the first and second pipes are fused with the sleeve when heated.
The jointing of TPE pipes without pollution and leakage is achieved, which avoids quality problems in the welding process and ensures the strength and stability of the jointed parts.
Smart Images
Figure CN119585100A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method of joining TPE tubes. Background Art
[0002] Thermoplastic elastomer (TPE) tubing or other components are often used in pharmaceutical and bioprocessing applications due to their desirable properties. In particular, TPE tubing can be used in conjunction with peristaltic pumps.
[0003] TPE tubing can be joined together using mechanical connectors and clamps. However, this can lead to contamination and leaks. While TPE tubing can be welded, many welding processes are not suitable due to processing limitations (e.g., material compatibility, cycle time, etc.) and quality attributes (e.g., poor surface quality, difficult pop-out of welded joints, graininess, etc.).
[0004] Therefore, there is a need to provide a method for joining TPE tubes to solve the problems associated with the prior art. Summary of the invention
[0005] According to one aspect of the present invention, a method for joining thermoplastic elastomer (TPE) tubes is provided, comprising: placing an end face of a first TPE tube against an end face of a second TPE tube; arranging a TPE sleeve around the first tube and the second tube so that the TPE sleeve overlaps the end faces; arranging a compression member around the sleeve, the compression member being configured to apply a radial force around the circumference of the sleeve; and fusing the first tube and the second tube and the sleeve to each other by applying heat to the sleeve while applying the radial force to the sleeve using the compression member.
[0006] The compression member may be a heat shrink tubing.
[0007] The heat shrink tube may be longer than the length of the sleeve, and may be arranged such that the heat shrink tube overhangs at both ends of the sleeve.
[0008] The sleeve may have an inner diameter corresponding to an outer diameter of the first tube and the second tube.
[0009] Longitudinal pressure may be applied to the first tube and the second tube during fusion.
[0010] Longitudinal pressure may be applied for only part of the time that heat is applied.
[0011] The wall thickness of the sleeve may be smaller than the wall thickness of the first tube and the second tube.
[0012] The wall thickness of the sleeve may be between 25% and 75% of the wall thickness of the first tube and the second tube.
[0013] The wall thickness of the sleeve may be 50% of the wall thickness of the first tube and the second tube.
[0014] The compression member may be removed after fusing. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Embodiments will now be described by way of example only with reference to the accompanying drawings, in which:
[0016] Figure 1 is a flow chart of a method according to an embodiment of the present invention;
[0017] Figure 2 is a cross-sectional view showing the first stage of the method;
[0018] Figure 3 is a cross-sectional view showing the second stage of the method;
[0019] Figure 4 is a cross-sectional view showing the third stage of the method;
[0020] Figure 5 a cross-sectional view showing a fourth stage of the method; and
[0021] Figure 6 A cross-sectional view of the sample after bonding is shown. DETAILED DESCRIPTION
[0022] Figure 1 Described is a method of joining two thermoplastic elastomer (TPE) tubes, which will refer to Figures 2 to 4 describe.
[0023] like Figure 2 As shown, in the first step S1 , the end surface of the first tube 2 abuts against the end surface of the second tube 4 .
[0024] In this example, the first tube 2 and the second tube 4 have the same inner diameter (i.e., bore diameter), outer diameter, and wall thickness. The first tube 2 and the second tube 4 are arranged so that the holes are aligned at the interface between the first tube 2 and the second tube 4. The first tube 2 and the second tube 4 may be prepared to ensure that they are clean and the end faces are vertical.
[0025] The first tube 2 and the second tube 4 may have an inner diameter between 0.5 mm and 25.4 mm and a wall thickness between 1.6 mm and 4.8 mm. For example, the tubes may range from a tube with an inner diameter of 0.5 mm and a wall thickness of 1.6 mm (thus, having an outer diameter of 3.7 mm) to a tube with an inner diameter of 25.4 mm and a wall thickness of 4.8 mm (thus, having an outer diameter of 35 mm). In this example, the first tube 2, the second tube 4 has an inner diameter of 12.7 mm, a wall thickness of 3.2 mm, and therefore an outer diameter of 19.1 mm.
[0026] In a second step S2, a TPE sleeve 6 (which may be of the same grade as the first tube 2 and the second tube 4) is arranged around the first tube 2 and the second tube 4 so that it overlaps the end face at the interface between the first tube 2 and the second tube 4. In this example, the interface between the first tube 2 and the second tube 4 is located at the center of the sleeve 6 so that the sleeve 6 extends an equal distance on the first tube 2 and the second tube 4.
[0027] The sleeve 6 is a short tube whose inner diameter corresponds to the outer diameter of the first tube 2 and the second tube 4. Therefore, in this example, the inner diameter of the sleeve 6 is 19.1 mm. In other examples, the sleeve 6 may have an inner diameter that is smaller than the outer diameter of the first tube 2 and the second tube 4, so that there is an interference fit between the first tube 2 and the second tube 4 and the sleeve 6. The sleeve 6 and / or the first tube 2 and the second tube 4 may be soft enough (i.e., have a sufficiently low durometer hardness value) to allow sufficient deformation, thereby allowing the first tube 2 and the second tube 4 to be easily inserted into the sleeve 6. In the case of providing an interference fit, it should be understood that once the first tube 2 and the second tube 4 are inserted into the sleeve 6, the inner diameter of the sleeve 6 corresponds to the outer diameter of the first tube 2 and the second tube 4. The wall thickness of the sleeve 6 may be less than the wall thickness of the first tube 2 and the second tube 4. For example, the wall thickness of the sleeve 6 may be 25% to 75% of the wall thickness of the first tube 2 and the second tube 4. In this example, the sleeve 6 has a wall thickness of 1.6 mm, which is therefore 50% of the wall thickness of the first tube 2 and the second tube 4. In this example, the sleeve 6 has a length of 20 mm, but in other examples the sleeve 6 may have a different length.
[0028] The sleeve 6 can be completely slid onto the first tube 2, and then once the end faces abut each other, the sleeve 6 is partially slid back onto the second tube 4. Alternatively, the sleeve 6 can be partially slid onto the first tube 2, and then the second tube 4 can be inserted into the sleeve 6 until the second tube 4 abuts the first tube 2.
[0029] like Figure 3 As shown, in a third step S3, a compression member is placed around the sleeve 6. In this example, the compression member is a heat shrink tubing 8 which may be formed of polyolefin or any other heat shrink material. As shown, the length of the heat shrink tubing 8 is greater than the length of the sleeve 6, and thus extends beyond both ends of the sleeve 6. The heat shrink tubing 8 is positioned to provide equal overhangs beyond both ends of the sleeve 6. In this example, the length of the heat shrink tubing 8 is 35 mm, and thus overhangs about 7.5 mm beyond both ends of the sleeve 6. Ideally, the length (L of the heat shrink tubing 8) is 1.5 mm. HST ) is greater than the length of the sleeve 6 (L S ) plus the wall thickness of the sleeve 6 at both ends (WT S )(i.e., L HST ≥L S +2WT SThe length of the heat shrink tubing 8 may also decrease during heating (by about 5% to 10%), and this should be taken into account when determining the required length (ie, increase in length).
[0030] The heat shrink tubing 8 has an inner diameter (as provided) that is greater than the outer diameter of the sleeve 6. In this example, the inner diameter of the heat shrink tubing 8 is 25.4 mm (compared to the 22.3 mm outer diameter of the sleeve). The heat shrink tubing 8 has a 2:1 shrink ratio, but other shrink ratios may also be suitable.
[0031] like Figure 4 and Figure 5 As shown, in a fourth step S4, heat is applied to the assembly, in particular the heat shrink tubing 8. This causes the heat shrink tubing 8 to shrink into engagement with the outer surface of the sleeve 6. Thus, as the assembly continues to be heated, the heat shrink tubing 8 compresses the sleeve 6 and simultaneously applies a radial force around the circumference of the sleeve 6. The heat shrink tubing 8 has a sufficient length so that it completely covers the end of the sleeve 6 and also contacts the outer surfaces of the first tube 2 and the second tube 4 on a small portion on both sides of the sleeve 6.
[0032] When heat is applied to the assembly, in addition to the radial force applied by the heat shrink tubing 8, longitudinal pressure (indicated by arrows) is applied to the first tube 2 and the second tube 4 so that the end faces are pressed together.
[0033] In this example, heat is applied by hot air from a heat gun. The temperature of the heat gun is set to 300°C and applied to the area for 80 seconds. Longitudinal pressure is applied to the first tube 2 and the second tube 4 only during part of the time that heat is applied. In particular, in this example, longitudinal pressure is applied only during the first 30 seconds.
[0034] The heat, compression and longitudinal pressure create fusion between the end faces of the first tube 2 and the second tube 4 and also between the inner surface of the sleeve 6 and the outer surface of the first tube 2 and the second tube 4. Figure 6 As shown in the sample of FIG. 1 , the first tube 2 and the second tube 4 and the sleeve 6 are completely fused to produce a single integrally formed component.
[0035] exist Figure 6 In the sample of , the heat shrink tubing 8 is removed from the assembly after heating. In other examples, the heat shrink tubing 8 can be left on the assembly.
[0036] Although the method has been described as using heat shrink tubing 8, it will be appreciated that other forms of compression members that apply radial pressure around the circumference of the sleeve to aid fusion may be used. For example, the compression member may be a mechanical device of variable diameter that can be contracted to apply radial force to the sleeve 6, such as an expandable ring.
[0037] The ends of the sleeve 6 (or a portion thereof) may be inclined so that they are not perpendicular to the outer surfaces of the first and second tubes 2, 4 and therefore taper into the outer surfaces of the first and second tubes 2, 4 in order to avoid abrupt steps and reduce the risk of restricting the inner bore. Alternatively, the taper of the sleeve 6 may be formed when it is melted. This may be achieved by applying additional force to the sleeve 6 to squeeze the material laterally away from the ends of the sleeve 6.
[0038] It will be appreciated that one of the tubes may form part of a connector component, such as a cross, Y or T-joint or flange component for a clamp. The sleeve 6 and heat shrink tubing 8 (or other compression member) may be provided with a connector component. Where the connector comprises multiple legs (such as a cross, Y or T-joint), these legs may be connected simultaneously to separate tubes. For example, a single heat gun may be provided with an adapter manifold that provides hot air to each leg simultaneously.
[0039] Although not shown, one or both of the tube and / or the connector part may be provided with a shoulder (eg a flange or boss) against which the sleeve 6 abuts in order to locate the sleeve 6 in the longitudinal direction.
[0040] The invention is not limited to the embodiments described herein and may be modified or adapted without departing from the scope of the invention.
Claims
1. A method for joining a thermoplastic elastomer (TPE) tube, comprising: The end surface of the first TPE tube is placed against the end surface of the second TPE tube; Disposing a TPE sleeve around the first tube and the second tube so that the sleeve overlaps the end surface; disposing a compression member about the sleeve, the compression member being configured to apply a radial force about a circumference of the sleeve; as well as The first and second tubes and the sleeve are fused to each other by applying heat to the sleeve while applying a radial force to the sleeve using the compression member.
2. The method according to claim 1, wherein: The compression member is a heat shrink tubing.
3. The method according to claim 2, wherein: The heat shrink tube has a length greater than that of the sleeve and is arranged such that the heat shrink tube overhangs at both ends of the sleeve.
4. A method according to any one of the preceding claims, wherein: The sleeve has an inner diameter corresponding to an outer diameter of the first tube and the second tube.
5. A method according to any one of the preceding claims, wherein: Longitudinal pressure is applied to the first tube and the second tube during fusion.
6. The method according to claim 5, wherein: The longitudinal pressure is applied only for part of the time that heat is applied.
7. A method according to any one of the preceding claims, wherein: The wall thickness of the sleeve is smaller than the wall thickness of the first tube and the second tube.
8. The method according to claim 7, wherein: The wall thickness of the sleeve is between 25% and 75% of the wall thickness of the first tube and the second tube.
9. The method according to claim 8, wherein: The wall thickness of the sleeve is 50% of the wall thickness of the first tube and the second tube.
10. A method according to any one of the preceding claims, wherein: The compression member is removed after fusing.