A pipe joint connected to a pipe

Abstract

The present invention provides a pipe joint connected to a pipe, which includes a joint body, an inner ring and a nut. A transition section is provided between the expanded conical surface and the reduced conical surface of the protruding portion of the inner ring. The axial length of the transition section is 15% to 30% of the axial length of the protruding portion. The angle between the tangent of any point on the outer surface of the transition section and the axial direction of the inner ring is 0° to 35°. The angle between the axial direction of the inner ring and the expanded conical surface is greater than the angle between the axial direction of the inner ring and the reduced conical surface. The outer surface of the transition section of the protruding portion forms a surface contact with the inner wall of the pipe, the effective area is increased, the extrusion force between the two is dispersed, and the transition section also reduces the bending curvature of the pipe, reduces the damage to the pipe, and realizes the close contact and fastening of the expanded conical surface with the inner wall of the pipe; and the angle between the axial direction of the inner ring and the expanded conical surface is greater than the angle between the axial direction of the inner ring and the reduced conical surface, so as to prevent the pipe from sliding outward along the reduced conical surface in a high temperature environment.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe connection, and in particular relates to a pipe joint used in fluid transportation and fluid processing processes. Background Art

[0002] US Patent No. 5743572A discloses a pipe joint commonly used in the manufacturing process of fluid transportation in the technical fields of semiconductor manufacturing, pharmaceuticals, food processing and chemical industry, as shown in the attached Figure 1 and 2 As shown, the pipe joint is composed of three parts: a joint body 1, an inner ring 2 and a nut 3. An annular groove 13 is formed between the outer cylinder 11 and the inner cylinder 12 of the joint body 1. When in use, the front end of the resin tube 4 is expanded and sleeved on the outer periphery of the inner ring 2, and then inserted into the joint body 1 together with the inner ring 2. The tube 4 is fixed inside the outer cylinder 11, and the insertion portion 21 of the inner ring 2 is inserted into the groove 13. The nut 3 is fastened to the outer periphery of the outer cylinder 11 of the joint body 1 through the screwing portion 31. The end of the inner ring 2 that contacts the tube 4 includes a protrusion 22 in the shape of a mountain, which expands the diameter of the tube 4 sleeved on its outer periphery, thereby preventing the tube 4 from falling off the inner ring 2.

[0003] The outer surface of the protrusion 22 of the inner ring 2 includes a tapered surface 221 that gradually expands from the end and a tapered surface 222 that gradually shrinks from the turning position. The tapered surface 221 with expanded diameter and the tapered surface 222 with reduced diameter are connected by a circular line 220, that is, the tapered surface 221 with expanded diameter and the tapered surface 222 with reduced diameter are directly connected. The circular line 220 corresponds to the thickest part of the protrusion 22. From the appearance, the thickest part is pointed. After the tube 4 is sleeved on the outer periphery of the inner ring 2, the outer periphery of the protrusion 22 abuts against the inner wall of the tube 4. The thickest part of the tip of the protrusion 22 is in the closest contact with the inner wall of the tube 4 and has the greatest extrusion force. However, only a line contact is formed between the two at this point, the action area is small, the action force is very concentrated, and a large curvature bend will appear in the corresponding bending area 41 of the tube 4. The combination of these two factors can easily cause damage to the tube 4. In addition, since the expanding conical surface 221 and the shrinking conical surface 222 are directly connected by only a circular line 220, the tube 4 sleeved on its outer periphery suddenly changes from expanding to shrinking. Near the area corresponding to the circular line 220, there is easily a certain gap between the inner wall of the tube 4 and the outer surface of the protrusion 22, that is, the inner wall near the bending area 41 of the tube 4 is not in close contact with the outer surface of the protrusion 22, and therefore, the sealing performance is not optimal.

[0004] In addition, since the inclination angles of the expanding conical surface 221 and the reducing conical surface 222 of the protrusion 22 are set unreasonably, when the inclination angle of the expanding conical surface 221 is too small and the inclination angle of the reducing conical surface 222 is relatively large, the expanding conical surface 221 and the reducing conical surface 222 are directly connected by only a circular line 220, which cannot effectively prevent the sliding of the pipe 4. When the pipe joint and the pipe 4 are used in a high-temperature environment, the pipe 4 is easily softened by heat and slides outward along the reducing conical surface 222, thereby causing leakage. Summary of the invention

[0005] In order to solve the problems that the protrusion of the inner ring of the existing pipe joint is easy to damage the pipe, the outer surface near the thickest part of the protrusion fails to closely contact with the inner wall of the pipe, and the pipe slides outward along the inner ring under high temperature environment, resulting in sealing failure, the present invention provides a pipe joint connected to the pipe. The pipe joint includes:

[0006] The joint body comprises a main body tube, an outer tube and an inner tube which are coaxially arranged, wherein the outer tube and the inner tube are arranged to protrude from the main body tube in the same direction, the inner tube is arranged inside the outer tube, the length of the outer tube protruding from the main body tube is greater than the length of the inner tube protruding from the main body tube, a groove is formed by the main body tube, the outer tube and the inner tube, and the opening direction of the groove is the same as the protruding direction of the outer tube and the inner tube;

[0007] An inner ring, which has a cylindrical insertion portion, a cylindrical fitting portion, a cylindrical connecting portion and a protruding portion which are coaxially and continuously arranged in sequence and a fluid passage located in the center, wherein the fitting portion is detachably fitted in the radial inner side of the outer cylindrical portion, the insertion portion is arranged to protrude from one side of the fitting portion and is inserted into the groove portion through the opening of the groove portion of the joint body, the connecting portion and the protruding portion are arranged to protrude from the other side of the fitting portion, the outer surface of the protruding portion includes a conical surface with an expanded diameter and a conical surface with a reduced diameter, the conical surface with an expanded diameter is located at the very end of the protruding portion, and the conical surface with a reduced diameter is located between the connecting portion and the conical surface with an expanded diameter, the protruding portion and the connecting portion are pressed into the interior of one end of the pipe and clamp the pipe between the protruding portion and the outer cylindrical portion, and the inner ring can be connected to or disconnected from the joint body in a state connected to the pipe;

[0008] A nut, which is fastened to the outer tube of the joint body through an internal thread, and fastens the pipe to the joint body together with the inner ring;

[0009] Among them, a transition section is provided between the expanding conical surface and the reducing conical surface, the axial length of the transition section is 15% to 30% of the axial length of the protrusion, the angle between the tangent at any point on the outer surface of the transition section and the axial direction of the inner ring is 0° to 35°, and the angle between the axial direction of the inner ring and the expanding conical surface is greater than the angle between it and the reducing conical surface.

[0010] The outer surface of the protrusion of the inner ring of the existing pipe joint includes a conical surface that gradually expands from the end and a conical surface that gradually shrinks from the turning position. The conical surface that expands and the conical surface that shrinks are connected by only a circular line, that is, the conical surface that expands and the conical surface that shrinks are directly connected. The circular line corresponds to the thickest part of the protrusion. From the appearance, the thickest part is pointed. The protrusion of the inner ring is inserted into the interior of one end of the pipe, and the outer periphery of the protrusion is against the inner wall of the pipe. The thickest part of the tip is in the closest contact with the inner wall of the pipe and has the greatest extrusion force. However, only a line contact is formed between the two here, the action area is small, the action force is very concentrated, and the pipe will have a large curvature bend in this area. The combination of these two factors will cause great damage to the pipe.

[0011] In the existing pipe joints, the expanding conical surface and the reducing conical surface of the protrusion of the inner ring are directly connected by only a circular line, and the pipe sleeved on its outer circumference changes from expanding to reducing abruptly. Near the area corresponding to the circular line, there is easily a certain gap between the inner wall of the pipe and the outer surface of the protrusion, that is, the inner wall of the corresponding area of ​​the pipe is not in close contact with the outer surface of the thickest part of the protrusion. Therefore, the sealing between the pipe joint and the pipe cannot reach the best.

[0012] In addition, due to unreasonable settings of the inclination angles of the expanding cone surface and the reducing cone surface of the protrusion, the inclination angle of the expanding cone surface is too small, and the inclination angle of the reducing cone surface is relatively large, and the expanding cone surface and the reducing cone surface are directly connected by only a circular line, which cannot effectively prevent the sliding of the pipe. When the pipe joint and the pipe are used in a high temperature environment, the pipe is easily slipped outward along the reducing cone surface after being softened by heat, thereby causing leakage.

[0013] The pipe joint provided by the present invention has a transition section between the expanded conical surface and the reduced conical surface of the protruding portion of the inner ring, and the axial length of the transition section is 15% to 30% of the axial length of the protruding portion. After the connecting portion and the protruding portion of the inner ring are inserted into the interior of one end of the pipe, the thickest part of the protruding portion forms a surface contact with the inner wall of the pipe through the outer surface of the transition section, the effective area is increased, the extrusion force between the two is dispersed, and the outer surface of the transition section also reduces the bending curvature of the pipe. The two effects are superimposed, which greatly reduces the damage to the pipe.

[0014] In addition, the angle between the tangent at any point on the outer surface of the transition section of the inner ring and the axial direction of the inner ring is 0° to 35°. When the protrusion is inserted into the interior of one end of the tube, the bending curvature of the tube always falls within its tolerable range, reducing damage to the tube and ensuring that the inner wall of the tube is in close contact with the outer surface of the protrusion without leaving any gaps, thereby improving the sealing effect between the tube and the inner ring.

[0015] In addition, the angle between the axial direction of the inner ring and the expanded conical surface is greater than the angle between the inner ring and the reduced conical surface, which makes the expanded conical surface at the end form an obstacle for the tube to slide outward along the reduced conical surface, and can prevent the tube from sliding outward along the reduced conical surface and the transition section. When the pipe joint and the tube are used in a high temperature environment, the tube may slide along the reduced conical surface for a certain distance after being softened by heat, but because the angle between the expanded conical surface at the end and the axial direction of the inner ring is greater than the angle between the reduced conical surface and the axial direction of the inner ring, the expanded conical surface can prevent the tube from sliding out, which is not conducive to the tube from sliding out, thereby ensuring the reliable sealing between the pipe joint and the tube in a high temperature environment.

[0016] Furthermore, the angle between the axial direction of the inner ring and the conical surface of the expanded diameter is 25 to 35 degrees, and the angle between the axial direction of the inner ring and the conical surface of the reduced diameter is 10 to 20 degrees.

[0017] When the angle between the axial direction of the inner ring and the tapered surface of the expanded diameter is 25 to 35 degrees, and the angle between the axial direction of the inner ring and the tapered surface of the reduced diameter is 10 to 20 degrees, it is ensured that under high temperature environment, the tube will not slide outward along the tapered surface of the reduced diameter and the sealing performance is good. The bending curvature of the tube is minimized as much as possible, so that the bending curvature of the tube is always within its tolerable range, thereby reducing damage to the tube and extending the service life of the tube.

[0018] Furthermore, the outer surface of the transition section is a cylindrical surface of equal diameter and is parallel to the axial direction of the inner ring, and the cylindrical surface has a certain axial length.

[0019] The expanded conical surface and the reduced conical surface are connected through the transition of the cylindrical surface. The cylindrical surface is not conducive to the sliding of the pipe, so the pipe can be prevented from sliding off the inner ring.

[0020] Furthermore, the outer surface of the transition section is a spherical surface.

[0021] The expanded conical surface and the reduced conical surface are connected by the spherical surface transition, the connection is smooth, the spherical surface is in closer contact with the inner wall of the tube, the sealing effect is better, and the deformation of the tube is gradual, which can reduce the bending curvature of the tube and reduce damage to the tube.

[0022] Furthermore, the radial distance between the point with the largest outer diameter of the transition section and the outer surface of the fluid channel is 1.5 to 2.5 times the radial distance between the outer surface of the connecting portion and the outer surface of the fluid channel.

[0023] Furthermore, the radial distance between the point where the outer diameter of the transition section is the largest and the outer surface of the fluid channel is 1.05 to 1.2 times the radial distance between the outer surface of the fitting portion and the outer surface of the fluid channel.

[0024] When the radial distance between the point with the largest outer diameter of the transition section of the protrusion and the outer surface of the fluid channel is 1.5 to 2.5 times the radial distance between the outer surface of the connecting portion and the outer surface of the fluid channel, and when the radial distance between the point with the largest outer diameter of the transition section and the outer surface of the fluid channel is 1.05 to 1.2 times the radial distance between the outer surface of the fitting portion and the outer surface of the fluid channel, the tube can be firmly clamped between the inner ring and the outer cylinder, thereby increasing the tightening force of the inner ring and the outer cylinder on the tube and preventing the tube from slipping out.

[0025] Furthermore, the inner ring further comprises a cylindrical abutment portion, which is coaxially arranged with the insertion portion and located radially inwardly on the same side of the insertion portion. After the inner ring is installed, the abutment portion contacts and abuts against the inner cylindrical portion of the joint body. The abutment portion further improves the sealing performance between the inner ring and the joint body.

[0026] Furthermore, the nut includes a threaded portion and a pressing portion, the threaded portion is threaded with the thread on the outer periphery of the outer tube portion, the pressing portion presses the tube and the inner ring toward the main tube portion, and presses the insertion portion into the groove portion, thereby fastening the inner ring and the tube to the joint body.

[0027] Furthermore, the radial thickness of the insert portion is equal to or slightly greater than the radial width of the groove portion, or the radial thickness of the insert portion is 1.2-1.5 times the radial width of the groove portion. On the premise that the insert portion can be smoothly inserted into the groove portion, the insert portion is firmly clamped in the groove portion.

[0028] Furthermore, the radial thickness of the insertion portion gradually decreases from the fitting portion to the end of the insertion portion, that is, the insertion portion is tapered at the front end. The tapered insertion portion is easier to insert into the groove, and the inner ring is easier to install.

[0029] The pipe joint provided by the present invention has a transition section between the expanded conical surface and the reduced conical surface of the protruding part of the inner ring, the axial length of the transition section is 15% to 30% of the axial length of the protruding part, the angle between the tangent of any point on the outer surface of the transition section and the axial direction of the inner ring is 0° to 35°, and the angle between the axial direction of the inner ring and the expanded conical surface is greater than the angle between the axial direction of the inner ring and the reduced conical surface. The outer surface of the transition section of the protruding part forms a surface contact with the inner wall of the pipe, the effective area is increased, the extrusion force between the two is dispersed, and the transition section also reduces the bending curvature of the pipe, reduces the damage to the pipe, and realizes the close contact and fastening of the expanded conical surface with the inner wall of the pipe; and the angle between the axial direction of the inner ring and the expanded conical surface is greater than the angle between the axial direction of the inner ring and the reduced conical surface, even if used in a high temperature environment, the pipe will not slide outward along the reduced conical surface and the transition section. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings:

[0031] Figure 1 A cross-sectional view of an inner ring of a pipe joint disclosed in the prior art

[0032] Figure 2 A cross-sectional view of a pipe joint and a pipe after installation according to the prior art

[0033] Figure 3 A cross-sectional view of an inner ring provided in Embodiment 1 of the present invention

[0034] Figure 4 A cross-sectional view of a pipe joint and a pipe after completion provided in the first embodiment of the present invention

[0035] Figure 5 For the general Figure 4 A partial cross-sectional view of the pipe fitting shown after the inner ring has been slid off the fitting body

[0036] Figure 6 A cross-sectional view of the inner ring provided in the second embodiment of the present invention

[0037] Figure 1-6 In: 1-connector body, 10-main cylinder, 11-outer cylinder, 12-inner cylinder, 13-groove, 2-inner ring, 20-fitting portion, 21-insertion portion, 22-protrusion, 220-circular line, 221-expanded conical surface, 222-reduced conical surface, 223-transition section, 23-connecting portion, 24-fluid channel, 25-abutment portion, 3-nut, 31-pressing portion, 32-threaded portion, 4-tube, 41-bending area. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0040] Embodiment 1

[0041] like Figure 3-4 As shown, the pipe joint includes:

[0042] The joint body 1 comprises a main body cylinder portion 10, an outer cylinder portion 11 and an inner cylinder portion 12 which are coaxially arranged. The outer cylinder portion 11 and the inner cylinder portion 12 are arranged to protrude from the main body cylinder portion 10 in the same direction. The inner cylinder portion 12 is arranged on the inner side of the outer cylinder portion 11. The length of the outer cylinder portion 11 protruding from the main body cylinder portion 10 is greater than the length of the inner cylinder portion 12 protruding from the main body cylinder portion 10. A groove portion 13 is formed by surrounding the main body cylinder portion 10, the outer cylinder portion 11 and the inner cylinder portion 12. The opening direction of the groove portion 13 is the same as the protruding direction of the outer cylinder portion 11 and the inner cylinder portion 12.

[0043] The inner ring 2 has a cylindrical insertion portion 21, a cylindrical fitting portion 20, a cylindrical connecting portion 23, a protruding portion 22 and a fluid channel 24 located in the center, which are coaxially and continuously arranged in sequence. The fitting portion 20 is removably fitted into the radial inner side of the outer cylindrical portion 11, and the insertion portion 21 is protruding from one side of the fitting portion 20 and is inserted into the groove portion 13 of the joint body 1 through the opening of the groove portion 13, and the connecting portion 23 and the protruding portion 22 are protruding from the other side of the fitting portion 20.

[0044] The protrusion 22 and the connection part 23 are pressed into one end of the tube 4 to sandwich the tube 4 between the protrusion 22 and the outer cylinder 11 . The inner ring 2 can be connected to or disconnected from the joint body 1 while being connected to the tube 4 .

[0045] The inner ring 2 further includes a cylindrical abutment portion 25, which is coaxially arranged with the insertion portion 21 and located radially inward on the same side of the insertion portion 21. After the inner ring 2 is installed, the abutment portion 25 contacts and abuts against the inner cylindrical portion 12 of the joint body 1. The abutment portion 25 further improves the sealing between the inner ring 2 and the joint body 1.

[0046] The nut 3 is fastened to the outer cylinder 11 of the joint body 1 by an internal thread, and fastens the pipe 4 to the joint body 1 together with the inner ring 2. The nut 3 includes a threaded portion 31 and a pressing portion 32, the threaded portion 31 is threaded with the thread on the outer periphery of the outer cylinder 11, and the pressing portion 32 presses the pipe 4 and the inner ring 2 toward the main cylinder 10, and presses the insertion portion 21 into the groove 13, thereby fastening the inner ring 2 and the pipe 4 to the joint body 1.

[0047] As attached Figure 3 As shown, the outer surface of the protrusion 22 includes an expanded conical surface 221, a reduced conical surface 222 and a transition section 223 located therebetween. The outer surface of the transition section 223 is a cylindrical surface of equal diameter. The expanded conical surface 221 is located at the very end of the protrusion 22, and the reduced conical surface 222 is located between the connecting portion 23 and the transition section 223.

[0048] The pipe joint provided by the present invention has a transition section 223 provided between the expanded conical surface 221 and the reduced conical surface 222 of the protrusion 22 of the inner ring 2, so that the expanded conical surface 221 and the reduced conical surface 222 are transitionally connected through the transition section 223.

[0049] After the connecting portion 23 and the protrusion 22 of the inner ring 2 are inserted into the interior of one end of the tube 4, the thickest part of the protrusion 22 forms a surface contact with the inner wall of the tube 4 through the outer surface of the transition section 223, the action area is increased, the extrusion force between the tube 4 and the protrusion 22 is dispersed, and the outer surface of the transition section 223 also reduces the bending curvature of the tube 4. The two effects are superimposed, which greatly reduces the damage to the tube 4. When the axial length W2 of the transition section 223 is 15% to 30% of the axial length W1 of the protrusion 22, the transition section 223 can disperse the extrusion force between the protrusion 22 and the tube 4, and the outer surface of the protrusion 22 can be in close contact with the inner wall of the tube 4 and minimize the bending curvature of the tube 4. When W2 / W1 is less than 15%, the extrusion action area between the tube 4 and the protrusion 22 is limited, and the extrusion force between the tube 4 and the protrusion 22 is still relatively large. After the pipe joint and the tube 4 are installed, leakage as shown in Table 1 will occur. When W2 / W1 is greater than 30%, the axial length W2 of the transition section 223 is too long, while the axial length W1 corresponding to the protrusion 22 is certain, and the axial lengths corresponding to the expanding conical surface 221 and the reducing conical surface 222 are too short, which will cause the angles between the expanding conical surface 221 and the reducing conical surface 222 and the axial direction of the inner ring 2 to be too large, and the bending curvature of the tube 4 will be relatively large, causing great damage to the tube 4.

[0050] Table 1 Tightness test results of pipe joints corresponding to the corresponding ratios of W2 / W1

[0051] W2 / W1 Is there any leakage during the initial connection? Reconnect to see if there is any leakage. 0.10 have have 0.12 none have 0.15 none none 0.18 none none 0.20 none none 0.22 none none 0.25 none none 0.28 none none 0.30 none none 0.32 none have 0.35 have have

[0052] The outer surface of the transition section 223 is a cylindrical surface parallel to the axial direction of the inner ring 2. The angle between the tangent at any point on the outer surface of the transition section 223 and the axial direction of the inner ring 2 is 0°. When the protrusion 22 is inserted into the interior of one end of the tube 4, the bending curvature of the tube 4 always falls within its tolerable range, reducing damage to the tube 4 and ensuring that the inner wall of the tube 4 is in close contact with the outer surface of the protrusion 22 without leaving any gaps, thereby improving the sealing effect between the tube 4 and the inner ring 2.

[0053] In addition, the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is greater than the angle θ2 between the expanded conical surface 221 and the reduced conical surface 222, so that the expanded conical surface 221 at the end forms an obstacle for the tube 4 to slide outward along the reduced conical surface 222, and can prevent the tube 4 from sliding out along the reduced conical surface 222 and the transition section 223. When the pipe joint and the tube 4 are used in a high-temperature environment, the tube 4 may slide along the reduced conical surface 222 for a certain distance after being softened by heat, but because the angle θ1 between the expanded conical surface 221 at the end and the axial direction of the inner ring 2 is greater than the angle θ2 between the reduced conical surface 222 and the axial direction of the inner ring 2, it is not conducive to the sliding of the tube 4, so the expanded conical surface 221 can prevent the tube 4 from sliding out, thereby ensuring the reliable sealing between the pipe joint and the tube 4 in a high-temperature environment.

[0054] Furthermore, when the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is 25 to 35°, and the angle θ2 between the axial direction of the inner ring 2 and the reduced conical surface 222 is 10 to 20°, it is ensured that under high temperature environment, the tube 4 will not slide outward along the reduced conical surface 222 and the sealing is good, and the bending curvature of the tube 4 is minimized as much as possible, so that the bending curvature of the tube 4 is always within its tolerable range, thereby reducing damage to the tube 4 and extending the service life of the tube 4.

[0055] When the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is greater than 35°, although the inner wall of the tube 4 is in close contact with the expanded conical surface 221, thereby ensuring the sealing between the pipe joint and the tube 4, the bending curvature of the corresponding area of ​​the tube 4 outside the expanded conical surface 221 is relatively large, and the damage to the tube 4 is also relatively large. If the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is further increased, the corresponding bending curvature of the tube 4 will also be further increased, and the damage to the tube 4 will be further increased. When the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is less than 25°, the contact and extrusion force between the inner wall of the tube 4 and the expanded conical surface 221 is insufficient. When used in a high temperature environment, the tube 4 becomes soft due to heat and may slip off the inner ring 2, so leakage as shown in Table 2 is likely to occur.

[0056] When the angle θ2 between the axial direction of the inner ring 2 and the tapered surface 222 of reduced diameter is less than 10°, the angle θ1 between the axial direction of the inner ring 2 and the tapered surface 221 of expanded diameter is also greater than 35°, and the inner wall of the tube 4 cannot be in close contact with and squeezed against the tapered surface 222 of reduced diameter. When used in a high-temperature environment, the tube 4 becomes soft due to heat and may slip out, and the tube 4 on the side corresponding to the tapered surface 221 of expanded diameter may also bend to a greater extent, and thus leakage as shown in Table 2 may easily occur. Since the axial lengths of the outer surfaces of the expanded conical surface 221, the reduced conical surface 222 and the transition section 223 corresponding to each other and the total axial length of the protrusion 22 are certain, the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 will change accordingly with the change of the angle θ2 between the axial direction of the inner ring 2 and the reduced conical surface 222. When the angle θ2 between the axial direction of the inner ring 2 and the reduced conical surface 222 is greater than 20°, the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 will be less than 25. As mentioned above, when the angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is less than 25°, the contact and extrusion force between the inner wall of the tube 4 and the expanded conical surface 221 is insufficient. When used in a high-temperature environment, the tube 4 becomes soft due to heat and may slip off the inner ring 2, so leakage as shown in Table 2 is likely to occur.

[0057] Table 2 The sealing test results of the corresponding angles θ1 and θ2 for the pipe joints

[0058] Angle θ1 / ° Angle θ2 / ° Is there any leakage during the initial connection? Reconnect to see if there is any leakage. 22 23 have have 24 21 none have 25 20 none none 28 17 none none 30 15 none none 30 14 none none 35 10 none none 36 9 none have

[0059] Furthermore, as attached Figure 5 As shown, the radial thickness of the insert 21 is D1, and the radial width of the groove 13 is D2. Verification data table 3 shows that when the radial thickness D1 of the insert 21 is 1.2-1.5 times the radial width D2 of the groove 13, the insert 21 can be inserted into the groove 13 relatively easily and can be firmly stuck in the groove 13. When the value of D1 / D2 is less than 1.2, although the insert 21 can be inserted into the groove 13 relatively smoothly, the insert 21 is not firmly stuck in the groove 13, and there is a risk of slipping out, so it is easy to cause sealing failure as shown in table 2. When the value of D1 / D2 is greater than 1.5, it is difficult for the insert 21 to be inserted into the groove 13.

[0060] Table 3 Tightness test results of pipe joints corresponding to the corresponding ratios of D1 / D2

[0061] D1 / D2 Is there any leakage during the initial connection? Reconnect to see if there is any leakage. 1.08 have have 1.12 have have 1.20 none none 1.35 none none 1.41 none none 1.50 none none 1.58 none none 1.64 none none

[0062] Furthermore, the radial thickness of the insertion portion 21 gradually decreases from the fitting portion 20 to the end of the insertion portion 21, that is, the insertion portion 21 is tapered. The tapered insertion portion 21 is easier to insert into the groove 13, and the inner ring 2 is easier to install.

[0063] As attached Figure 3 As shown in FIG. 1 , the radial distance L1 between the point with the largest outer diameter of the transition section 223 and the outer surface of the fluid channel 24 is 1.5 to 2.5 times the radial distance L2 between the outer surface of the connecting portion 23 and the outer surface of the fluid channel 24. The actual effect of this parameter is that the thickest part of the protrusion 22 protrudes a certain height from the outer surface of the connecting portion 23, so that the tube 4 can be tightly clamped between the outer cylinder 11 and the protrusion 22 and the connecting portion 23. When the ratio of L1 / L2 is less than 1.5, the tube 4 cannot be tightly clamped by the outer cylinder 11 and the protrusion 22. When in a high temperature environment, the tube 4 softens due to heat and slides off the inner ring 2, resulting in a sealing failure problem as shown in Table 4. When the ratio of L1 / L2 is greater than 2.5, the tube 4 is firmly stuck between the outer tube 11 and the protrusion 22. However, after the pipe joint and the tube 4 are installed, due to the tightening force of the nut 3, the squeezing force of the outer tube 11 on the protrusion 22 is too large, and the protrusion 22 is deformed toward the inside of the fluid channel 24 and the fluid channel 24 becomes smaller, which is not conducive to the flow of the fluid.

[0064] Table 4 Tightness test results of pipe joints corresponding to the corresponding ratio of L1 / L2

[0065] L1 / L2 ratio Is there any leakage during the initial connection? Reconnect to see if there is any leakage. 1.35 have have 1.46 have have 1.50 none none 1.7 none none 1.8 none none 2.0 none none 2.3 none none 2.5 none none 2.7 none none

[0066] As attached Figure 3 As shown, the radial distance L1 between the point with the largest outer diameter of the transition section 223 and the outer surface of the fluid channel 24 is 1.05 to 1.2 times the radial distance L3 between the outer surface of the fitting 20 and the outer surface of the fluid channel 24. When the value of L1 / L3 is 1.05 to 1.2, the outer periphery of the fitting 20 is in close contact with the inner wall of the outer cylinder 11, and the transition section 223 and the outer cylinder 11 corresponding to the thickest part of the protrusion 22 tightly clamp the tube 4, and the tube 4 will not slip out of the pipe joint even in a high temperature environment. When the ratio of L1 / L3 is less than 1.05, the tube 4 is not tightly clamped by the outer cylinder 11 and the protrusion 22. In a high temperature environment, the tube 4 slips out of the inner ring 2 due to softening due to heat, resulting in a sealing failure problem as shown in Table 5. When the ratio of L1 / L3 is greater than 1.2, the transition section 223 corresponding to the thickest part of the outer cylinder 11 and the protrusion 22 can tightly clamp the pipe 4. However, after the pipe joint and the pipe 4 are installed, due to the tightening force of the nut 3, the squeezing force of the outer cylinder 11 on the protrusion 22 is too large, resulting in the protrusion 22 deforming toward the inside of the fluid channel 24 and causing the fluid channel 24 to become smaller, which is not conducive to the flow of the fluid.

[0067] Table 5 Tightness test results of pipe joints corresponding to the corresponding ratio of L1 / L3

[0068] L1 / L3 Is there any leakage during the initial connection? Reconnect to see if there is any leakage. 1.00 have have 1.03 have have 1.05 none none 1.10 none none 1.12 none none 1.16 none none 1.20 none none 1.25 none none

[0069] Embodiment 2

[0070] As attached Figure 6 As shown, in another structure of the inner ring 2, the outer surface of the transition section 223 of the protrusion 22 is a spherical surface, that is, the expanded conical surface 221 and the reduced conical surface 222 are connected by the spherical surface transition. The connection is a smooth connection, the spherical surface is in closer contact with the inner wall of the tube 4, the sealing effect is better, and the deformation of the tube 4 is gradual, which can reduce the bending curvature of the tube 4 and reduce damage to the tube 4.

[0071] The angle θ3 between the tangent line at any point on the spherical surface and the axial direction of the inner ring 2 is 0° to 35°, and the spherical surface is tangent to the expanded conical surface 221 and the reduced conical surface 222 at the intersection. At the intersection with the expanded conical surface 221, the angle θ3 between the tangent line of the spherical surface and the axial direction of the inner ring is 35°, at the intersection with the reduced conical surface 222, the angle θ3 between the tangent line of the spherical surface and the axial direction of the inner ring is 20°, and at the point where the outer diameter of the spherical surface is the largest, the angle θ3 between the tangent line of the spherical surface and the axial direction of the inner ring is 0°.

[0072] The angle θ1 between the axial direction of the inner ring 2 and the expanded conical surface 221 is greater than the angle θ2 between the expanded conical surface 221 and the reduced conical surface 222, so that the expanded conical surface 221 at the end forms an obstacle for the tube 4 to slide out along the reduced conical surface 222, and can prevent the tube 4 from sliding out along the reduced conical surface 222 and the transition section 223. When the pipe joint and the tube 4 are used in a high-temperature environment, the tube 4 may slide along the reduced conical surface 222 for a certain distance after being softened by heat. However, since the angle θ1 between the expanded conical surface 221 at the end and the axial direction of the inner ring 2 is greater than the angle θ2 between the reduced conical surface 222 and the axial direction of the inner ring 2, the expanded conical surface 221 can prevent the tube 4 from sliding out, thereby ensuring reliable sealing between the pipe joint and the tube 4 in a high-temperature environment. The angle θ1 is set at 25-35° and the angle θ2 is set at 10-20° to ensure that the tube 4 will not slide outward along the tapered surface 222 under high temperature environment and that reliable sealing is achieved. The bending curvature of the tube 4 is minimized as much as possible, so that the bending curvature of the tube 4 is always within its tolerable range, thereby reducing damage to the tube 4 and extending the service life of the tube 4.

[0073] A radial distance L1 between a point where the outer diameter of the transition section 223 is the largest and the outer surface of the fluid channel 24 is 1.5 to 2.5 times the radial distance L2 between the outer surface of the connecting portion 23 and the outer surface of the fluid channel 24 .

[0074] Furthermore, a radial distance L1 between a point where the outer diameter of the transition section 223 is the largest and an outer surface of the fluid channel 24 is 1.05 to 1.2 times a radial distance L3 between an outer surface of the fitting portion 20 and an outer surface of the fluid channel 24 .

[0075] When the radial distance L1 between the point with the largest outer diameter of the transition section 223 of the protrusion 22 and the outer surface of the fluid channel 24 is 1.5 to 2.5 times the radial distance L2 between the outer surface of the connecting portion 23 and the outer surface of the fluid channel 24, and when the radial distance L1 between the point with the largest outer diameter of the transition section 223 and the outer surface of the fluid channel 24 is 1.05 to 1.2 times the radial distance L3 between the outer surface of the fitting portion 20 and the outer surface of the fluid channel 24, the tube 4 can be firmly clamped between the inner ring 2 and the outer cylinder portion 11, thereby increasing the tightening force of the inner ring 2 and the outer cylinder portion 11 on the tube 4 and preventing the tube 4 from slipping out.

[0076] The preferred embodiments of the present invention have been described in detail above, but it should be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention. These equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A pipe joint connected to a pipe. include: The joint body comprises a main body tube, an outer tube and an inner tube which are coaxially arranged, wherein the outer tube and the inner tube are arranged to protrude from the main body tube in the same direction, the inner tube is arranged inside the outer tube, the length of the outer tube protruding from the main body tube is greater than the length of the inner tube protruding from the main body tube, a groove is formed by the main body tube, the outer tube and the inner tube, and the opening direction of the groove is the same as the protruding direction of the outer tube and the inner tube; An inner ring, which has a cylindrical insertion portion, a cylindrical fitting portion, a cylindrical connecting portion and a protruding portion coaxially arranged in sequence and a fluid passage located in the center, the fitting portion being detachably fitted in the radial inner side of the outer cylindrical portion, the insertion portion being protruding from one side of the fitting portion and being inserted into the groove portion through the opening of the groove portion of the joint body, the connecting portion and the protruding portion being protruding from the other side of the fitting portion, the outer surface of the protruding portion comprising a conical surface of an expanded diameter and a conical surface of a reduced diameter, the conical surface of the expanded diameter being located at the very end of the protruding portion, the conical surface of the reduced diameter being located between the connecting portion and the conical surface of the expanded diameter, the protruding portion and the connecting portion being pressed into the interior of one end of a pipe and clamping the pipe between the protruding portion and the outer cylindrical portion, and the inner ring being able to be connected to or disconnected from the joint body in a state connected to the pipe; A nut, which is fastened to the outer tube of the joint body through internal threads, and fastens the pipe to the joint body together with the inner ring; characterized in that: A transition section is provided between the expanded conical surface and the reduced conical surface, the axial length of the transition section is 15% to 30% of the axial length of the protruding portion, the angle between the tangent line at any point on the outer surface of the transition section and the axial direction of the inner ring is 0° to 35°, and the radial distance between the point with the largest outer diameter of the transition section and the outer surface of the fluid channel is 1.5 to 2.5 times the radial distance between the outer surface of the connecting portion and the outer surface of the fluid channel; The angle between the axial direction of the inner ring and the expanding conical surface is greater than the angle between it and the reducing conical surface. The angle between the axial direction of the inner ring and the expanding conical surface is 25° to 35°, and the angle between the axial direction of the inner ring and the reducing conical surface is 10° to 20°.

2. A pipe joint connected to a pipe according to claim 1, It is characterized in that The outer surface of the transition section is a cylindrical surface with equal diameter and is parallel to the axial direction of the inner ring, and the transition section has a certain axial length.

3. A pipe joint connected to a pipe according to claim 1, It is characterized in that The outer surface of the transition section is a spherical surface.

4. A pipe joint connected to a pipe according to claim 2 or 3, It is characterized in that The radial distance between the point with the largest outer diameter of the transition section and the outer surface of the fluid channel is 1.05 to 1.2 times the radial distance between the outer surface of the fitting portion and the outer surface of the fluid channel.

5. A pipe joint connected to a pipe according to claim 1, It is characterized in that The inner ring also includes a cylindrical abutment portion, which is coaxially arranged with the insertion portion and located radially inward on the same side of the insertion portion. After the inner ring is installed, the abutment portion contacts and abuts the inner cylindrical portion of the joint body.

6. A pipe joint connected to a pipe according to claim 1, It is characterized in that The nut includes a threaded portion and a pressing portion, wherein the threaded portion is threaded with the threads on the outer periphery of the outer tube portion, and the pressing portion presses the tube and the inner ring toward the main tube portion, pressing the insertion portion into the groove portion, thereby fastening the inner ring and the tube to the joint body.

7. A pipe joint connected to a pipe according to claim 1, It is characterized in that The radial thickness of the inserting portion is equal to or slightly greater than the radial width of the groove portion, or the radial thickness of the inserting portion is 1.2-1.5 times the radial width of the groove portion.

8. A pipe joint connected to a pipe according to claim 1, It is characterized in that In the direction extending from the fitting portion to the end of the insertion portion, the radial thickness of the insertion portion gradually decreases, that is, the insertion portion is in a shape of a tapered front end.

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