A split ring structure and hydraulic expansion device

Abstract

The application provides a split ring structure and a hydraulic expansion device. The split ring structure is used for sleeving an outer wall of a mandrel and is located in a pipe. The split ring structure comprises a split ring. The split ring has a first outer diameter and a second outer diameter. The first outer diameter is smaller than the second outer diameter. The split ring is used for sealing cooperation with the pipe at the second outer diameter. There is a cooperation gap between the split ring at the first outer diameter and the pipe. The split ring of the application is a variable-diameter structure. On the premise of ensuring that the split ring meets a sealing state, the probability of contact between the outer wall of the split ring and the inner wall of the pipe is reduced as much as possible by reducing the outer diameter of the split ring, so that the probability of scratching the inner wall of the pipe when the split ring is opened is reduced. The quality of the pipe hole after expansion meets the expansion requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic expansion, in particular to a split ring structure and a hydraulic expansion device. BACKGROUND

[0002] In the field of nuclear power plant steam generator and heat exchanger products, a large number of tube-tubesheets need to be hydraulically expanded. Hydraulic expansion is a mechanical connection method that makes the tube plastically deform and the tube-sheet elastically deform by liquid pressure to achieve tight connection of the tube and the tube-sheet. Through hydraulic expansion, the gap between the tube and the tube-sheet can be eliminated, preventing liquid from seeping into the tube wall to cause corrosion, and preventing alternating stress on the tube-tube-sheet weld due to tube bundle vibration from causing weld failure. Hydraulic expansion also increases the mechanical strength of the tube-tube-sheet connection.

[0003] The equipment used for expansion is a hydraulic expansion device and an expansion gun, and the split ring is a key component of hydraulic expansion. The structure and size of the split ring directly affect the quality of the tube-tube-sheet expansion. For example, after the tube-tube-sheet seal weld of a steam generator product, the tube hole needs to be hydraulically expanded. The hydraulic expansion pressure is ≥3100 bar, the tube wall thickness is 1.35 mm, the tube hole diameter is φ12.3 mm, and the tube-tube-sheet seal weld tube hole diameter is φ12.1 mm. Due to the thick tube wall, small tube hole diameter, long expansion length of 254 mm, and high expansion pressure, the expansion difficulty is extremely high. At the same time, the quality requirements for the inner wall of the tube hole after expansion are high. After expansion, the inner surface of the expanded tube is generally inspected using an endoscope. The inner wall of the tube hole should not have any cracks or scratches, and the use of lighting equipment (illumination ≥500 lux) is not allowed to exist in the 40 mm deep area from the tube hole. The conventional split ring structure, due to the small tube diameter and high expansion pressure, causes the split ring to open at the longitudinal split position when high-pressure liquid passes through the center of the mandrel to generate high pressure. This causes the split ring to locally contact the inner wall of the tube at the split end position, causing scratches on the inner surface of the tube, such as circumferential and longitudinal scratches, thereby affecting the expansion quality of the tube-tube-sheet. SUMMARY

[0004] The problem to be solved by the present application is that the existing split ring structure is prone to produce circumferential and longitudinal scratches on the inner surface of the tube during expansion, affecting the expansion quality.

[0005] To solve at least one of the above problems, the present application provides a split ring structure for being sleeved on the outer wall of a mandrel and located in a tube, comprising a split ring, the split ring having a first outer diameter and a second outer diameter, the first outer diameter being smaller than the second outer diameter, the split ring being configured to sealingly engage with the tube at the second outer diameter, and the split ring having a fitting gap between the first outer diameter and the tube.

[0006] Preferably, the split ring structure comprises a first split ring part, a second split ring part, and a transition structure connecting the first split ring part and the second split ring part, the first split ring part has the first outer diameter, the second split ring part has the second outer diameter, and the transition structure is a variable diameter structure.

[0007] Preferably, the first outer diameter is 11.3 mm, and the second outer diameter is 11.7 mm.

[0008] Preferably, the inner diameter of the first split ring part is equal to the inner diameter of the second split ring part, and the wall thickness of the first split ring part is smaller than the wall thickness of the second split ring part.

[0009] Preferably, the wall thickness of the first split ring part is 1.3 mm, and the wall thickness of the second split ring part is 1.5 mm.

[0010] Preferably, the split ring structure further comprises an inner sleeve, the inner sleeve is arranged on the outer wall of the mandrel, and the split ring is arranged on the outer wall of the inner sleeve.

[0011] Preferably, the outer diameter of the inner sleeve is 9.5 mm, and the wall thickness of the inner sleeve is 0.36 mm.

[0012] Preferably, a plurality of longitudinal slits are arranged on the outer wall of the split ring in a circumferential direction, and the longitudinal slits extend to one end of the split ring in a longitudinal direction.

[0013] The split ring structure of the present application has the following advantages compared with the prior art:

[0014] The split ring of the present application has two parts with different diameters, which is a variable diameter structure. The part with a larger diameter is used for sealing cooperation with the pipe to play a sealing role. The part with a smaller diameter increases the cooperation gap between the pipe inner wall, which provides space for the deformation of the split ring under high pressure, thereby increasing the anti-deformation ability of the split ring, avoiding scratching the pipe inner wall during the hydraulic expansion process. The present application reduces the probability of contact between the outer wall of the split ring and the inner wall of the pipe as much as possible under the premise of ensuring that the split ring meets the sealing state, thereby reducing the probability of scratching the pipe inner wall when the split ring is opened, and ensuring that the quality of the expanded pipe hole meets the expansion requirements.

[0015] The present application also provides a hydraulic expansion device arranged in a pipe, which comprises a mandrel and a split ring structure as described above, and the split ring structure is arranged on the outer wall of the mandrel.

[0016] Preferably, a center hole is arranged in the mandrel along the axis, the center hole is used for the high-pressure liquid to enter, and the end of the center hole is provided with a radial hole penetrating the mandrel, the radial hole is perpendicular to and communicates with the center hole.

[0017] The advantages of the expansion device of the present application are the same as those of the split ring structure of the prior art, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The first split ring cross section of the split ring structure of the comparative example of the present application is shown in the figure.

[0019] Figure 2 The first inner sleeve cross section of the split ring structure of the comparative example of the present application is shown in the figure.

[0020] Figure 3 The three-dimensional structure of the split ring structure of the embodiment of the present application is shown in the figure.

[0021] Figure 4 The cross section of the split ring structure of the embodiment of the present application is shown in the figure.

[0022] Figure 5 The side view of the split ring structure of the embodiment of the present application is shown in the figure.

[0023] Figure 6 The split ring structure of the embodiment of the present application is shown in the figure.

[0024] Figure 7 The cross section of the split ring of the embodiment of the present application is shown in the figure.

[0025] Figure 8 The cross section of the inner sleeve of the embodiment of the present application is shown in the figure.

[0026] Figure 9 The expansion principle of the embodiment of the present application is shown in the figure.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 101-First split ring; 102-First inner sleeve; 103-First longitudinal slit;

[0029] 1-Split ring; 2- Inner sleeve; 3- Mandrel; 4- Sealing ring; 5- Adapter; 6- Tube sheet base material; 7- Tube; 8- Gap between the tube and the tube sheet; 9- High-pressure liquid; 10- Longitudinal slit. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0031] Please refer to Figures 3-9 As shown in the figure, the split ring structure of the embodiment of the present application is used for sleeving the outer wall of the mandrel 3 and is located in the pipe 7, and comprises a split ring 1, the split ring 1 has a first outer diameter and a second outer diameter, the first outer diameter is smaller than the second outer diameter, the split ring 1 is used for sealing cooperation with the pipe 7 at the second outer diameter, and there is a cooperation gap between the split ring 1 and the pipe 7 at the first outer diameter.

[0032] The split ring 1 of the embodiment has two parts with different diameters, which is a variable-diameter structure, wherein the part with a larger diameter is used for sealing cooperation with the pipe 7 to play a sealing role, and the part with a smaller diameter increases the cooperation gap between the split ring 1 and the inner wall of the pipe 7, which is used for providing a space for deformation of the split ring 1 under high-strength pressure, thereby increasing the anti-deformation ability of the split ring 1, avoiding scratching the inner wall of the pipe 7 during the hydraulic expansion process, and ensuring the quality of the pipe hole after expansion to meet the expansion requirements under the condition of ensuring sealing.

[0033] In some embodiments, a plurality of longitudinal slits 10 are distributed on the outer wall of the split ring 1 in the circumferential direction, and the longitudinal slits 10 extend to one end of the split ring 1 in the longitudinal direction. Figure 3 、 Figure 5 As shown in the figure, the longitudinal slits 10 are provided on the outer wall of the split ring 1 and extend through the end, and a plurality of longitudinal slits 10 are uniformly distributed in the circumferential direction. Under the action of high pressure, the longitudinal slits 10 at the end of the split ring 1 will be opened, thereby playing a sealing role of the split ring 1.

[0034] In some embodiments, the split ring 1 comprises a first split ring part, a second split ring part, and a transition structure connecting the first split ring part and the second split ring part, the outer diameter of the first split ring part is the first outer diameter, the outer diameter of the second split ring part is the second outer diameter, and the transition structure is a variable-diameter structure.

[0035] In the embodiment, the split ring 1 is composed of a first split ring part, a transition structure, and a second split ring part, so that the entire split ring 1 is a variable-diameter structure. By reducing the outer diameter of the first split ring part, a cooperation gap resisting deformation is formed between the outer wall of the split ring 1 and the inner wall of the pipe 7, the deformation space of the split ring 1 under high-strength pressure is increased, and the split ring 1 is prevented from scratching the inner wall of the pipe 7 when deformed under high-strength pressure.

[0036] In some embodiments, the first outer diameter is 11.3 mm, and the second outer diameter is 11.7 mm. In this way, the diameter of the transition structure gradually transitions from 11.3 mm to 11.7 mm, realizing the transition connection between the two split ring parts.

[0037] In some embodiments, the inner diameter of the first slit ring portion is equal to the inner diameter of the second slit ring portion, and the wall thickness of the first slit ring portion is less than the wall thickness of the second slit ring portion.

[0038] In this embodiment, the inner diameter of the entire split ring 1 remains unchanged. Since the outer diameter of the first split ring portion is smaller than that of the second split ring portion, the wall thickness of the first split ring portion is smaller than that of the second split ring portion. The second split ring portion needs to be sealed with the inner wall of the pipe 7 to achieve a sealing effect. Therefore, in this embodiment, by increasing the wall thickness of the second split ring portion, the rigidity of the split ring 1 is increased. Under the same cutting and cutting force, the cutting or cutting deformation of the split ring 1 is smaller. During the processing of the split ring 1, the amount of deformation caused by processing can be reduced. At the same time, the increased wall thickness can improve the strength of the split ring 1, further increasing the deformation resistance of the split ring structure.

[0039] In some embodiments, the second slit ring portion is located at the end of the slit ring 1, and the wall thickness of the second slit ring portion is 1.3 mm.

[0040] In this embodiment, the end wall thickness of the split ring 1 is increased to 1.3 mm. This increased wall thickness improves the strength of the split ring 1 and enhances the deformation resistance of the variable-diameter split ring structure. Simultaneously, the increased end wall thickness of the split ring 1 also reduces the amount of deformation caused by machining during the processing of the end notch.

[0041] In some embodiments, an inner sleeve 2 is further included, which is used to fit onto the outer wall of the mandrel 3, and the split ring 1 is fitted onto the outer wall of the inner sleeve 2. The inner sleeve 2 is disposed inside the split ring 1 and provides support for the split ring 1 to improve the strength of the entire split ring structure.

[0042] like Figure 8 As shown, a boss is provided on the outer wall of the end of the inner sleeve 2, and a notch is provided on the inner wall of the end of the slit ring 1 to mate with the boss. Thus, the connection between the slit ring 1 and the inner sleeve 2 is achieved through the limiting effect of the boss and the notch. Preferably, the mating surface of the boss and the notch is set as an inclined surface.

[0043] For ease of comparison, a comparative example is provided. Figure 1 , Figure 2 This diagram shows a comparative example of an equal-diameter slit ring structure, which includes a first slit ring 101 and a first inner sleeve 102. Figure 1 A cross-sectional schematic diagram of the first slit ring 101 with dimensions is shown. Figure 2 A schematic cross-sectional view of the first inner sleeve with dimensions is shown. According to... Figure 1It can be seen that the first split ring 101 is a cylindrical structure, the outer diameter is 12mm, the length is 25mm, and the opening part is uniformly distributed with 6 first longitudinal slits 103 in the circumferential direction. According to the application, the first split ring 101 is provided with a first inner sleeve 102, and the first inner sleeve 102 is arranged in the first split ring 101. Figure 2 It can be seen that the outer diameter of the first inner sleeve 102 is 10mm, and the wall thickness is 0.6mm.

[0044] The working principle of hydraulic expansion is that the hydraulic expansion machine injects high-pressure water into the expansion gun mandrel 3, seals through the O-ring and split ring 1, expands the inner diameter of the tube bundle to fit the tube plate tube hole by relying on the pressure of high-pressure water, eliminates the gap 8 between the tube and the tube plate, reduces the corrosion problem of in-service operation, and when the hydraulic pressure increases, the O-ring deforms while pressing the support ring and the split ring 1, so that the split ring 1 and the support ring deform together, realize the transition of the final size of hydraulic expansion, and at the same time reduce the stress concentration point of the final expansion point.

[0045] Figure 6 The schematic diagram of the split ring structure in the embodiment is shown, Figure 7 the split ring 1 is a cross-sectional schematic diagram, Figure 8 the split ring 1 is a cross-sectional schematic diagram. The split ring 1 adopts a cylindrical variable-diameter structure, the outer diameter of the split ring 1 is 11.3mm and 11.7mm respectively, forming a variable-diameter structure, increasing the anti-deformation ability of the split ring 1 in the sealed state, the length of the split ring 1 is 25mm, the split ring 1 tail opening part is uniformly distributed with 6 longitudinal slits in the circumferential direction, the outer diameter of the inner sleeve 2 of the split ring 1 is 9.5mm, and the wall thickness of the inner sleeve 2 is 0.36mm.

[0046] As can be seen, compared with the first split ring 101 of the conventional constant-diameter split ring in the comparative example, the split ring 1 of the embodiment changes from a constant-diameter structure with a diameter of 12mm to a variable-diameter structure with one end diameter of 11.3mm and the other end diameter of 11.7mm, the second split ring part with a diameter of 11.7mm is in sealing cooperation with the inner wall of the pipe 7 to ensure sealing, and the first split ring part with a diameter of 11.3mm is as small as possible to reduce the probability of contact with the inner wall of the pipe 7, thereby reducing the probability of damage to the inner wall of the pipe 7. That is, the embodiment increases the cooperation gap between the split ring 1 and the pipe 7 by 0.3mm under the premise of ensuring the sealing of the hydraulic expansion pipe 7, and increases the deformation space of the split ring 1 under high pressure. As shown in Figure 6 the diameter of the second split ring part of the split ring 1 is 11.7mm, and the length is 4.3mm, that is, at least 4.3mm of the split ring is in sealing cooperation with the inner wall of the pipe to meet the sealing requirement, and the diameter of the remaining length of the split ring can be appropriately reduced to increase the gap with the inner wall of the pipe and reduce the probability of contact with the inner wall of the pipe.

[0047] It can also be seen by comparison that the wall thickness of the split ring 1 of the embodiment is increased as a whole, specifically, the first split ring part is increased from 1 mm to 1.3 mm in wall thickness, the second split ring part is increased from 1 mm to 1.5 mm in wall thickness, the wall thickness of the split ring 1 is increased by 0.3 mm, and the wall thickness of the end opening position is increased by 0.5 mm. The thickness of the split ring 1 is increased, the strength of the split ring 1 is improved, and the anti-deformation ability of the split ring structure is increased. At the same time, the deformation amount generated in the processing process is also reduced due to the increased wall thickness of the end of the split ring 1.

[0048] It can also be seen by comparison that the diameter of the inner sleeve 2 of the embodiment is reduced from 10 mm to 9.5 mm, and the wall thickness is reduced from 0.6 mm to 0.36 mm. By reducing the outer diameter of the split ring 1, increasing the thickness of the split ring 1, and reducing the size of the inner sleeve 2, the split ring 1 is prevented from scratching the inner wall of the pipe hole during hydraulic expansion, so that the quality of the pipe hole after the chapter meets the expansion requirements.

[0049] The embodiment re-designs the structure of the split ring of the hydraulic expansion rod, which is a key component of the hydraulic expansion gun, and optimizes the sealing device of the high-pressure hydraulic expansion rod. The structure and size of the split ring after design can strictly control the size and quality of the inner wall of the pipe hole after hydraulic expansion, ensure that the hydraulic expansion length is controlled within 0.5 mm, and the inner wall of the pipe hole after expansion is smooth without any scratches or damage. Through the optimization design of the split ring of the hydraulic expansion rod, the operation precision and expansion quality of the hydraulic expansion are ensured.

[0050] The embodiment of the application also provides a hydraulic expansion device for being arranged in a pipe 7, which comprises a mandrel 3 and a split ring structure as described above, and the split ring structure is sleeved on the outer wall of the mandrel 3.

[0051] As shown in Figure 9 The hydraulic expansion device mainly comprises an adapter 5, a split ring, a sealing ring 4, a support ring, and a mandrel 3, the mandrel 3 is threadedly connected with the adapter 5, and the sealing ring 4 is preferably an O-ring. The working principle of the tube bundle hydraulic expansion is that the hydraulic tube expander injects high-pressure water into the mandrel 3 of the hydraulic expansion device, seals through the O-ring and the split ring, and expands the inner diameter of the tube bundle to be in contact with the pipe hole of the tube sheet, so as to eliminate the gap 8 between the pipe and the tube sheet and reduce the corrosion problem in service. When the hydraulic pressure increases, the O-ring deforms and at the same time presses the support ring and the split ring 1, so that the split ring 1 and the support ring deform together, the transition of the hydraulic expansion termination size is realized, and the stress concentration point of the final expansion point is reduced.

[0052] In some embodiments, a center hole is arranged in the mandrel 3 along the axis, the center hole is used for the high-pressure liquid 9 to enter, and an end of the center hole is provided with a radial hole penetrating through the mandrel 3, the radial hole is perpendicular to and communicates with the center hole.

[0053] In the embodiment, the mandrel 3 is provided with a central hole for the high-pressure liquid 9 to pass into, and a radial hole communicated with the central hole. The high-pressure liquid 9 is sprayed between the outer wall of the mandrel 3 and the inner wall of the pipe 7 through the central hole and the radial hole. The end of the split ring 1 is expanded in the longitudinal split position under the action of the high pressure, and together with the sealing ring 4, it seals the pipe hole. The high pressure generated by the high-pressure liquid 9 makes the pipe 7 plastically deform and the pipe plate base material 6 elastically deform. After a period of time, the high pressure is removed, the elastic deformation of the pipe plate base material 6 returns to the original state, but the plastic deformation of the pipe 7 remains in the state of increased diameter and does not return to the original state, so that the pipe 7 is tightly connected with the pipe plate.

[0054] In summary, the embodiment changes the split ring 1 to a variable diameter structure, increases the wall thickness, and reduces the outer diameter of the split ring 1. Under high pressure, the deformation resistance of the split ring 1 is increased, and the split ring 1 is prevented from scratching the inner wall of the pipe hole during hydraulic expansion. In the sealed state, the quality of the expanded pipe hole meets the expansion requirements.

[0055] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present disclosure.

Claims

1. A hydraulic expansion device, characterized in that, For installation inside a tube (7), including an adapter (5), a split ring (1), a sealing ring (4), a support ring, and a mandrel (3), the split ring (1) is used to fit around the outer wall of the mandrel (3) and is located inside the tube (7), the split ring (1) has a first outer diameter and a second outer diameter, the first outer diameter being smaller than the second outer diameter, the split ring (1) is used to seal against the tube (7) at the second outer diameter, the split ring (1) has a fitting gap with the tube (7) at the first outer diameter, the split ring (1) includes a first split ring portion, a second split ring portion, and a connecting portion to the first outer diameter. A transition structure between a first slit ring portion and a second slit ring portion, wherein the outer diameter of the first slit ring portion is the first outer diameter, and the outer diameter of the second slit ring portion is the second outer diameter, the transition structure is a variable diameter structure, a plurality of longitudinal notches (10) are distributed circumferentially on the outer wall of the slit ring (1), and the longitudinal notches (10) extend longitudinally to the end of the second outer diameter of the slit ring (1), a central hole is provided in the inner axis of the mandrel (3), the central hole is used to allow high pressure liquid (9) to enter, and a radial hole penetrating the mandrel (3) is provided at the end of the central hole, the radial hole being perpendicular to and communicating with the central hole.

2. The hydraulic expansion device according to claim 1, characterized in that, The first outer diameter is 11.3 mm, and the second outer diameter is 11.7 mm.

3. The hydraulic expansion device according to claim 2, characterized in that, The inner diameter of the first slit ring portion is equal to the inner diameter of the second slit ring portion, and the wall thickness of the first slit ring portion is less than the wall thickness of the second slit ring portion.

4. The hydraulic expansion device according to claim 3, characterized in that, The wall thickness of the first slit ring is 1.3 mm, and the wall thickness of the second slit ring is 1.5 mm.

5. The hydraulic expansion device according to claim 4, characterized in that, It also includes an inner sleeve (2), which is used to be fitted onto the outer wall of the mandrel (3), and the slit ring (1) is fitted onto the outer wall of the inner sleeve (2).

6. The hydraulic expansion device according to claim 5, characterized in that, The outer diameter of the inner sleeve (2) is 9.5 mm, and the wall thickness of the inner sleeve (2) is 0.36 mm.

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