CN211010248U - Pipe joint connected with pipe - Google Patents
Pipe joint connected with pipe Download PDFInfo
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- CN211010248U CN211010248U CN201921815979.2U CN201921815979U CN211010248U CN 211010248 U CN211010248 U CN 211010248U CN 201921815979 U CN201921815979 U CN 201921815979U CN 211010248 U CN211010248 U CN 211010248U
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Abstract
The utility model relates to a coupling with tube coupling, it includes joint main part and nut, the joint main part includes external screw thread portion and forms in the terminal union coupling portion of external screw thread portion, union coupling portion includes constant diameter portion and hole enlargement portion, this hole enlargement portion includes first hole enlargement portion and second hole enlargement portion, second hole enlargement portion is formed at the end of first hole enlargement portion, the surface of first hole enlargement portion is the partly of sphere, the surface of second hole enlargement portion is the partly of conical surface, the holistic external diameter of second hole enlargement portion is less than the holistic external diameter of first hole enlargement portion. The pipe is sleeved on the periphery of the pipe connecting part, the reducing part of the pipe is firstly matched and attached with the second expanding part with the smaller outer diameter and then matched and attached with the first expanding part with the larger outer diameter, namely, the reducing part of the pipe forms smaller bending deformation firstly and forms larger bending deformation secondly, the reducing part is formed through gradual change and not abrupt change, the bending change of the reducing part is gentle, and the damage to the pipe can be reduced.
Description
Technical Field
The invention belongs to the technical field of pipe fitting connection, and particularly relates to a pipe joint for fluid conveying and fluid processing processes.
Background
US5332271 and US 54677 disclose a pipe joint suitable for use in high temperature environments, as shown in fig. 3, which comprises an enlarged diameter pipe member 28 and a nut 10, the enlarged diameter pipe member 28 comprising an external thread 38 and a cylindrical portion 36, the inner surface of the nut 10 being provided with an internal thread 20 for mating and screwing with the external thread 38 and an annular clamping surface 25, the tip of the cylindrical portion 36 forming a spherical enlarged diameter portion, the enlarged diameter portion and the external thread 38 being connected by an equal diameter portion. The pipe 26 with the diameter expanded is sleeved on the periphery of the cylindrical part 36, the inner wall of the large diameter part of the pipe 26 is attached to the outer surface of the equal diameter part, the inner wall of the reducing part of the pipe 26 is attached to the outer surface of the spherical expanding part, the internal thread 20 and the external thread 38 of the nut 10 are screwed, and the annular clamping surface 25 contacts and presses the reducing part of the pipe 26, so that sealing connection is formed.
However, since the enlarged diameter portion of the tip of the cylindrical portion 36 includes only a spherical configuration, the tube 26 must undergo a relatively large bending deformation, i.e., the portion of the tube 26 extending from the normal diameter thereof abruptly undergoes a relatively large bending deformation, thereby forming a diameter-variable portion that matches and closely conforms to the spherical enlarged diameter portion of the tip of the cylindrical portion 36. Because the reducing part is formed suddenly and directly and the bending deformation is large, the pipe wall of the corresponding area has the risks of cracking and leaking. In addition, in order to adapt to the high temperature application environment, the material of the pipe 26 is usually PFA, PFA has certain hardness, when the pipe 26 is expanded, it is difficult to ensure that the shape of the diameter-variable portion of the pipe 26 is completely matched with the shape of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, and a certain gap is easily formed between the inner wall of the diameter-variable portion of the pipe 26 and the outer surface of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, that is, the inner wall of the diameter-variable portion of the pipe 26 is not in close contact with the outer surface of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, and both of them do not form the best sealing.
Therefore, it is necessary to further improve the structure of the diameter-expanded portion at the tip end of the cylindrical portion 36 so that the structure of the diameter-expanded portion is more gradual, and the curvature of the diameter-reduced portion of the tube is gradually changed, thereby reducing the damage to the tube and improving the sealing connection effect between the two.
SUMMERY OF THE UTILITY MODEL
The utility model aims to reach the purpose of providing a new coupling, make the deformation of the reducing part of pipe mild, and then reduce the damage to the pipe, simultaneously, improve the sealing connection effect between coupling and pipe.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a pipe joint connected with a pipe comprises a joint main body and a nut, wherein the joint main body comprises an external thread part, a pipe connecting part and a fluid channel, the pipe connecting part is positioned at the tail end of the external thread part, the fluid channel is formed in the hollow inner part of the joint main body and extends in the whole axial length range of the joint main body, the pipe connecting part comprises an equal-diameter part and an expanded-diameter part, the outer diameter of the expanded-diameter part is gradually increased from the tail end to the equal-diameter part, the equal-diameter part is cylindrical and is formed at the tail end of the external thread part, the expanded-diameter part is formed at the tail end of the equal-diameter part, the nut comprises an internal thread part and a through hole, and the internal thread part and the external thread part are matched and screwed;
the diameter expanding part comprises a first diameter expanding part and a second diameter expanding part, the second diameter expanding part is formed at the tail end of the first diameter expanding part, the outer surface of the first diameter expanding part is a part of a spherical surface, and the outer surface of the second diameter expanding part is a part of a conical surface;
the first diameter-expanding portion is gradually reduced in outer diameter from the starting end to the tail end, the second diameter-expanding portion is reduced in diameter from the starting end to the tail end, and the overall outer diameter of the second diameter-expanding portion is smaller than that of the first diameter-expanding portion.
In the conventional pipe joint, the diameter-expanded portion of the tip of the cylindrical portion 36 of the diameter-expanded pipe member 28 has only a spherical structure, and the pipe 26 is fitted and tightly attached to the spherical diameter-expanded portion of the tip of the cylindrical portion 36 through a diameter-expanded portion. Since the variable diameter portion of the pipe 26 is formed abruptly and directly and has a large bending deformation, there is a risk of rupture and leakage of the pipe wall corresponding to the variable diameter portion. Further, since the material of the tube 26 is hard, when the diameter of the tube 26 is expanded, it is difficult to ensure that the shape of the diameter-variable portion of the tube 26 completely matches the shape of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, and a certain gap is easily formed between the inner wall of the diameter-variable portion of the tube 26 and the outer surface of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, that is, the inner wall of the diameter-variable portion of the tube 26 does not closely contact the outer surface of the spherical diameter-expanded portion of the tip of the cylindrical portion 36, and both of them do not provide an optimal sealing effect.
The utility model provides a pipe joint, it includes joint main part and nut, and the union coupling portion of joint main part includes constant diameter portion and hole enlargement portion, and this hole enlargement portion includes first hole enlargement portion and second hole enlargement portion, and second hole enlargement portion is formed at the end of first hole enlargement portion, and the surface of first hole enlargement portion is the partly of sphere, and the surface of second hole enlargement portion is the partly of conical surface. The first diameter-expanded portion has an outer diameter gradually decreasing in a direction from the starting end toward the end, the second diameter-expanded portion extends from the starting end toward the end in a diameter-reduced manner, and the entire outer diameter of the second diameter-expanded portion is smaller than the entire outer diameter of the first diameter-expanded portion.
The diameter-variable part of the pipe is firstly matched and jointed with a second diameter-variable part which is positioned at the tail end of the whole diameter-variable part and has a smaller outer diameter, and then is matched and jointed with a first diameter-variable part with a larger outer diameter, namely, the diameter-variable part of the pipe firstly forms a smaller bending deformation and then forms a slightly larger bending deformation, the smaller bending deformation is matched and jointed with the second diameter-variable part, and the slightly larger bending deformation is matched and jointed with the first diameter-variable part.
The reducing part of the pipe is firstly a small bending deformation part and then a slightly large bending deformation part, namely the reducing part of the pipe is formed by gradual change and not abrupt change, so that the bending change of the whole reducing part of the pipe is gentle, the tensile acting force applied to the pipe in the expanding operation and use process can be reduced, the damage to the pipe is reduced, the pipe wall corresponding to the reducing part of the pipe is prevented from being broken, and further the leakage is avoided.
Furthermore, the ratio of the axial length of the second diameter-expanding part to the axial length of the first diameter-expanding part is 0.4-3.
During the connection and use of the pipe joint and the pipe, the fact that the reducing part of the pipe is firstly matched and jointed with the second expanded diameter part with smaller overall external diameter and then matched and jointed with the first expanded diameter part with slightly larger overall external diameter is discovered, when the ratio of the axial length of the second expanded diameter part to the axial length of the first expanded diameter part is 0.4-3, namely the ratio of the axial length of the reducing part of the pipe corresponding to the second expanded diameter part to the axial length of the first expanded diameter part is approximately 0.4-3, the reducing part of the pipe is ensured to firstly undergo small bending deformation with enough length and then form a slightly large bending deformation, the bending deformation of the reducing part of the pipe is further slowed, the tensile force borne by the pipe during the expanding operation and the use process is reduced, the damage to the pipe is further reduced, and simultaneously the reducing part of the pipe is ensured to respectively have enough long contact and long contact with the second expanded diameter part and the first expanded diameter part, Sealing length to avoid the tube slipping out from the periphery of the tube connection.
Further, the outer diameter of the equal-diameter part is 1.2-2 times of the outer diameter of the tail end of the second diameter-expanding part.
Before the pipe is sleeved on the periphery of the pipe connecting part of the joint main body, the pipe needs to be subjected to expanding operation, when the outer diameter of the equal-diameter part of the pipe connecting part is 1.2-2 times of the outer diameter of the tail end of the second expanding part, the inner diameter of the large-diameter part of the pipe matched with the pipe and connected with the pipe is 1.2-2 times of the inner diameter of the small-diameter part (the original inner diameter of the pipe), namely, after the pipe is subjected to expanding operation, the maximum inner diameter of the reducing part of the pipe is approximately equal to 1.2-2 times of the inner diameter of the small-diameter part (the original inner diameter of the pipe), and in the whole area corresponding to the reducing part, the bending deformation of the pipe always falls within the bearable range of the pipe, so that the damage to the pipe can be reduced, the inner walls of the large-diameter part and the reducing part of the pipe are ensured to be in close contact with the whole outer surface of the pipe.
Further, the tip of the second diameter-enlarged portion has the same inner diameter and outer diameter.
The pipe sleeved on the periphery of the pipe connecting part is gradually increased in inner diameter from the tail end of the second diameter-expanding part, and when the inner diameter and the outer diameter of the tail end of the second diameter-expanding part are equal, the inner diameter of the pipe at the initial position where the diameter expansion occurs is not excessively larger than the original inner diameter of the pipe, so that the tensile acting force on the pipe in the diameter expansion process can be reduced, and the damage to the pipe is reduced.
Furthermore, the included angle between the outer surface of the second diameter-expanding part and the axis of the joint body is 35-55 degrees.
When the included angle between the outer surface of the second diameter-expanding part and the axis of the joint main body is 35-55 degrees, the bending deformation of the reducing part of the pipe matched and attached with the outer surface of the second diameter-expanding part always falls within the bearable range, the damage to the pipe is reduced, the inner wall of the reducing part of the pipe can be closely attached to the outer surface of the second diameter-expanding part, no gap is reserved, and the sealing performance between the pipe and the pipe connecting part is improved.
Furthermore, the starting end of the outer surface of the second diameter-expanding part and the tail end of the outer surface of the equal-diameter part are respectively tangent to the two ends of the outer surface of the first diameter-expanding part.
The two ends of the outer surface of the first diameter-expanding part are respectively tangent with the starting end of the outer surface of the second diameter-expanding part and the tail end of the outer surface of the equal-diameter part, namely, the two ends of the outer surface of the first diameter-expanding part are respectively and smoothly connected with the starting end of the outer surface of the second diameter-expanding part and the tail end of the outer surface of the equal-diameter part, namely, the whole outer surface of the whole pipe connecting part is smooth everywhere, so that the inner wall of the pipe sleeved on the periphery of the pipe is ensured to be tightly attached to the pipe, and reliable.
Furthermore, the inner diameter of the through hole is larger than the outer diameter of the tail end of the second diameter-expanding part and smaller than the outer diameter of the starting end of the second diameter-expanding part, and a pressing part is formed outside the through hole.
After the pipe passes through the through hole of the nut, the pipe is sleeved on the periphery of the pipe connecting part, the large-diameter part of the pipe is positioned on the periphery of the equal-diameter part of the pipe connecting part, the reducing part is positioned on the peripheries of the first expanding part and the second expanding part, the nut is screwed in towards the direction of the joint body, and after the screw thread is screwed up, the pressing part presses and holds the reducing part of the pipe to tightly press the pipe, so that reliable sealing is ensured.
Furthermore, a spacing part is arranged between the internal thread part of the nut and the pressing part, and the inner surface of the spacing part is a smooth cylindrical surface.
Further, the distance between the inner surface of the spacer portion and the axis of the nut is smaller than the distance between the internal thread portion and the axis of the nut.
Further, after the joint main body, the nut and the pipe are installed, the pipe comprises a large-diameter part and a reducing part, and a gap is reserved between the inner surface of the spacing part and the outer surface of the large-diameter part of the pipe.
Still be equipped with the spacer between the internal thread portion of nut and the splenium, the internal surface of this spacer is smooth cylinder face, the joint main part, the back is accomplished in nut and the pipe installation, the pipe forms major diameter part and reducing part, leave certain clearance between the internal surface of spacer and the major diameter partial surface of pipe, the spacer does not produce the squeezing action to the major diameter part of pipe promptly, consequently, when precessing the nut to joint main part side, do not produce extrusion force or frictional force between the internal surface of the partial surface of major diameter of pipe and spacer, the precession operation of nut is more laborsaving.
In addition, after the pipe joint and the pipe are connected, because the temperature of the processed fluid is usually higher, such as 100 ℃, the pipe is often expanded and increased in size due to heat, and because the distance between the inner surface of the spacing part and the axis of the nut is smaller than the distance between the inner surface of the spacing part and the axis of the nut, when the pipe is expanded and increased due to heat, the inner surface of the spacing part can contact and generate a certain squeezing effect on the outer surface of the pipe, so that the pipe is prevented from being expanded excessively and the connection sealing performance between the pipe joint and the pipe is prevented from being adversely affected.
The utility model discloses in, the coupling with union coupling includes joint main part and nut, the joint main part includes external screw thread portion and forms in the terminal union coupling portion of external screw thread portion, union coupling portion includes constant diameter portion and hole enlargement portion, this hole enlargement portion includes first hole enlargement portion and second hole enlargement portion, second hole enlargement portion is formed at the end of first hole enlargement portion, the surface of first hole enlargement portion is the partly of sphere, the surface of second hole enlargement portion is the partly of conical surface, the holistic external diameter of second hole enlargement portion is less than the holistic external diameter of first hole enlargement portion.
The reducing part of the pipe is firstly matched and jointed with the second expanding part which is positioned at the tail end of the whole expanding part and has smaller outer diameter, and then is matched and jointed with the first expanding part with larger outer diameter, namely, the reducing part of the pipe forms smaller bending deformation and forms larger bending deformation, and the reducing part of the pipe is formed by gradual change and not abrupt change, so that the bending change of the whole reducing part of the pipe is gentle, the tensile acting force on the pipe in the expanding operation and use process can be reduced, the damage to the pipe is reduced, the pipe wall corresponding to the reducing part of the pipe is prevented from being broken, and further the leakage is avoided.
Drawings
The present invention will be further explained with reference to the accompanying drawings:
fig. 1a and 1b are cross-sectional views of a joint body provided by the present invention;
FIG. 2 is an enlarged view of a portion of A of FIG. 1 a;
FIG. 3 is a cross-sectional view of a nut mated with the connector body provided in FIG. 1 a;
FIG. 4 is a cross-sectional view of the coupling body provided in FIG. 1a, the nut provided in FIG. 3, and a pipe after the coupling is completed; in FIGS. 1a-4, 1-joint body, 10-external thread portion, 11-tube connecting portion, 110-constant diameter portion, 111-enlarged diameter portion, 111-1-first enlarged diameter portion, 111-2-second enlarged diameter portion, 12-fluid channel, 2-nut, 20-internal thread portion, 21-pressing portion, 22-spacing portion, 23-through hole, 3-tube, 30-large diameter portion, 31-variable diameter portion, 32-small diameter portion.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
As shown in fig. 1a, the joint body 1 includes an externally threaded portion 10, a pipe connecting portion 11, and a fluid passage 12, the pipe connecting portion 11 being located at a distal end of the externally threaded portion 10, the fluid passage 12 being formed in a hollow interior of the joint body 1 and extending over the entire axial length of the joint body 1.
The pipe connecting portion 11 includes an equal diameter portion 110 and an enlarged diameter portion 111, the equal diameter portion 110 being cylindrical and formed at the end of the male screw portion 10, and the enlarged diameter portion 111 being formed at the end of the equal diameter portion 110. The outer diameter of the constant diameter portion 110 is smaller than that of the external thread portion 10, and the constant diameter portion 110 and the external thread portion 10 are connected by an arc transition.
The outer diameter of the equal diameter part 110 is the largest part of the outer diameter of the pipe connecting part 11, and there is a radial height difference between the male screw part 10 and the equal diameter part 110, and after the pipe 3 is sleeved on the outer periphery of the equal diameter part 110, the pipe 3 is positioned at the radial inner side of the male screw part 10, so that the nut 2 sleeved on the outer periphery of the pipe 3 can be screwed in and tightened towards the male screw 10.
As shown in FIG. 2, the diameter-enlarged portion 111 includes a first diameter-enlarged portion 111-1 and a second diameter-enlarged portion 111-2, the second diameter-enlarged portion 111-2 is formed at the end of the first diameter-enlarged portion 111-1, i.e., the end of the constant diameter portion 110 is connected to the start end of the first diameter-enlarged portion 111-1, and the end of the first diameter-enlarged portion 111-1 is connected to the start end of the second diameter-enlarged portion 111-2.
The outer surface of the first diameter-enlarging portion 111-1 is a part of a spherical surface, and the outer surface of the second diameter-enlarging portion 111-2 is a part of a conical surface. The first diameter-enlarged part 111-1 has an outer diameter gradually decreasing from the starting end toward the end. The starting end of the second expanded diameter portion 111-2 is just the end of the first expanded diameter portion 111-1, the second expanded diameter portion 111-2 extends from the starting end to the end in a diameter-reduced manner, and the overall outer diameter of the second expanded diameter portion 111-2 is smaller than the overall outer diameter of the first expanded diameter portion 111-1.
The distal end of the second enlarged diameter portion 111-2 has an unequal inner diameter and outer diameter, i.e., the outer diameter is larger than the inner diameter, and a plane having a certain height, such as a plane perpendicular to the axial direction of the joint body 1 shown in fig. 1a, is formed at the distal end of the second enlarged diameter portion 111-2.
Alternatively, as shown in FIG. 1b, the inner and outer diameters of the distal end of the second enlarged diameter portion 111-2 are equal, i.e., the inner and outer surfaces of the second enlarged diameter portion 111-2 are directly connected at the distal end. The inner diameter of the tube 3 at the initial position of the diameter expansion is not increased too much compared with the original inner diameter of the tube 3, so that the tensile acting force on the tube 3 in the diameter expansion process can be reduced, and the damage to the tube 3 can be reduced.
The starting end of the outer surface of the second expanded diameter portion 111-2 and the end of the outer surface of the equal diameter portion 110 are respectively tangent to the two ends of the outer surface of the first expanded diameter portion 111-1, that is, the two ends of the outer surface of the first expanded diameter portion 111-1 are respectively smoothly connected with the starting end of the outer surface of the second expanded diameter portion 111-2 and the end of the outer surface of the equal diameter portion 110, that is, the whole outer surface of the whole pipe connecting portion 11 is smooth everywhere, so that the inner wall of the pipe 3 sleeved on the outer periphery thereof is ensured to be tightly attached to the pipe connecting portion, and reliable sealing is provided.
After the pipe 3 is expanded, the pipe 3 is fitted and attached to the outer periphery of the pipe connecting portion 11, that is, the large diameter portion 30 of the pipe 3 is fitted and attached to the outer periphery of the equal diameter portion 110, and the reduced diameter portion 31 is fitted and attached to the outer periphery of the expanded diameter portion 111.
Since the diameter-enlarged part 111 includes the second diameter-enlarged part 111-2 having a smaller overall outer diameter and the first diameter-enlarged part 111-1 having a slightly larger outer diameter, the diameter-reduced part 31 of the tube 3 is first matched and attached to the second diameter-enlarged part 111-2 having a smaller outer diameter at the end of the entire diameter-enlarged part 111, and then matched and attached to the first diameter-enlarged part 111-1 having a larger outer diameter between the constant diameter part 110 and the second diameter-enlarged part 111-2, that is, the diameter-reduced part 31 of the tube 3 is first formed with a smaller bending deformation and then formed with a slightly larger bending deformation, the smaller bending deformation is matched and attached to the second diameter-enlarged part 111-2, and the slightly larger bending deformation is matched and attached to the first diameter-enlarged part 111-1.
Because the reducing part 31 of the tube 3 is a smaller bending deformation part firstly and then a slightly larger bending deformation part, namely the reducing part 31 of the tube 3 is formed by gradual change and not abrupt change, the bending change of the whole reducing part 31 of the tube 3 is gentle, thereby reducing the tensile acting force applied to the tube 3 in the expanding operation and use process, reducing the damage to the tube 3, preventing the tube wall corresponding to the reducing part 31 of the tube 3 from being broken, and further avoiding the occurrence of leakage.
When the ratio of the axial length of the second expanded diameter part 111-2 to the axial length of the first expanded diameter part 111-1 is 0.4-3, the ratio of the axial length of the variable diameter part 31 of the tube 3 corresponding to the second expanded diameter part 111-2 to the axial length of the first expanded diameter part 111-1 is also approximately 0.4-3, which ensures that the variable diameter part 31 of the tube 3 firstly undergoes a small bending deformation with a sufficient length and then forms a slightly large bending deformation with a sufficient length, which also further makes the bending deformation of the variable diameter part 31 of the tube 3 smooth, reduces the tensile force borne by the tube 3 during the expanding operation and use, and further reduces the damage to the tube 3, and simultaneously ensures that the variable diameter part 31 of the tube 3 has a sufficiently long contact between the second expanded diameter part 111-2 and the first expanded diameter part 111-1, A sealing length to prevent the tube 3 from slipping out from the outer circumference of the tube connecting part 11.
Further, when the outer diameter of the equal diameter portion 110 of the pipe connecting portion 11 is 1.2 to 2 times the outer diameter of the tip end of the second enlarged diameter portion 111-2, the inner diameter of the large diameter portion 30 of the pipe 3 is 1.2 to 2 times the inner diameter of the small diameter portion 32 (the original inner diameter of the pipe 3), that is, after the diameter of the pipe 3 is expanded, the maximum inner diameter of the diameter-variable portion 31 is about 1.2 to 2 times the inner diameter of the small-diameter portion 32 (the original inner diameter of the pipe 3), in the entire region corresponding to the variable diameter portion 31, the bending deformation of the tube 3 always falls within its tolerable range, thereby reducing damage to the pipe 3 and ensuring that the inner walls of the large-diameter part 30 and the variable diameter part 31 of the pipe 3 are in close contact with the whole outer surface of the pipe connecting part 11 without leaving a gap, and further improving the sealing connection effect between the pipe 3 and the whole pipe connecting part 11.
In addition, in order to ensure that the bending deformation of the variable diameter portion 31 of the pipe 3 always falls within a tolerable range and avoid damaging the pipe 3, an angle between the outer surface of the second enlarged diameter portion 111-2 and the axis of the joint body 1 is limited to 35 ° to 55 °. At this time, the inner wall of the diameter-variable portion 31 of the pipe 3 can be closely adhered to the outer surface of the second diameter-increased portion 111-2 without leaving a gap, and the sealing property between the pipe 3 and the pipe connecting portion 11 is improved.
The pipe 3 is fitted and bonded to the outer periphery of the pipe connecting portion 11, the large diameter portion 30 of the pipe 3 is fitted and bonded to the equal diameter portion 110, and the reduced diameter portion 31 is fitted and bonded to the enlarged diameter portion 111. When the axial length of the equal diameter part 110 is 2 to 3.5 times the axial length of the enlarged diameter part 111, the axial length of the large diameter part 30 of the tube 3 is 2 to 3.5 times the axial length of the variable diameter part 31, which ensures a sufficient contact and sealing length between the tube 3 and the enlarged diameter part 111 and the equal diameter part 110 of the tube connecting part 11, and prevents the tube 3 from slipping out of the outer periphery of the tube connecting part 11.
As shown in fig. 3, the nut 2 includes an internal thread portion 20, a pressing portion 21, and a through hole 23, and the pressing portion 21 is formed outside the through hole 23. The female screw portion 20 is adapted to be screwed with the male screw portion 10 of the joint body 1. Further, the nut 2 has a spacer 22 between the female screw portion 20 and the pressing portion 21, and the inner surface of the spacer 22 is a smooth cylindrical surface.
As shown in fig. 4, the joint body 1, the nut 2 and the pipe 3 are assembled, the pipe 3 has a large diameter portion 30, a reduced diameter portion 31 and a small diameter portion 32, and the small diameter portion 32 is a portion where the inner diameter of the pipe 3 is not changed and has an inner diameter which is the original inner diameter of the pipe 3.
The pipe 3 is fitted around the outer periphery of the pipe connecting portion 11 of the joint body 1 through the through hole 23 of the nut 2, specifically, the reduced diameter portion 31 of the pipe 3 is closely attached to the outer periphery of the second enlarged diameter portion 111-2 of the enlarged diameter portion 111 and the outer periphery of the first enlarged diameter portion 111-1 in this order, and the large diameter portion 30 is closely attached to the outer periphery of the equal diameter portion 110 of the pipe connecting portion 11.
The nut 2 and the coupling body 1 are screwed together by the female screw portion 20 and the male screw portion 10, and since the inner diameter of the through hole 23 is larger than the outer diameter of the end of the second diameter-expanded portion 111-2 and smaller than the outer diameter of the starting end of the second diameter-expanded portion 111-1, the pressing portion 21 formed outside the through hole 23 can contact and press the outer surface of the diameter-variable portion 31 of the pipe 3, thereby preventing the pipe 3 from slipping out from the outer periphery of the pipe connecting portion 11 and securing a reliable sealing effect between the pipe 3 and the coupling.
Since a certain gap is left between the inner surface of the spacer 22 of the nut 2 and the outer surface of the large-diameter portion 30 of the pipe 3, that is, the spacer 22 does not press the large-diameter portion 30 of the pipe 3, when the nut 2 is screwed into the joint body 1, no pressing force or frictional force is generated between the outer surface of the large-diameter portion 30 of the pipe 3 and the inner surface of the spacer 22, and the screwing operation of the nut 2 is more labor-saving.
In addition, after the pipe joint and the pipe 3 are connected, since the temperature of the fluid to be treated is generally high, such as 100 ℃, the pipe 3 is often expanded due to heat and becomes large in size, and since the distance between the inner surface of the spacer 22 and the axis of the nut 2 is smaller than the distance between the inner surface of the internal thread portion 20 and the axis of the nut 2, the pipe 3 is expanded, and after the size becomes large, the inner surface of the spacer 22 can contact and exert a certain pressing action on the outer surface of the large diameter portion 30 of the pipe 3, thereby preventing the pipe 3 from being excessively expanded and avoiding the adverse effect on the sealing performance of the connection between the pipe joint and the pipe 3.
The preferred embodiments of the present invention have been described in detail, but it should be understood that various changes and modifications can be made by those skilled in the art after reading the above teaching of the present invention. Such equivalents are intended to fall within the scope of the claims appended hereto.
Claims (10)
1. A pipe joint connected with a pipe, comprising a joint body and a nut, wherein the joint body comprises an external thread part, a pipe connecting part and a fluid passage, the pipe connecting part is positioned at the tail end of the external thread part, the fluid passage is formed in the hollow inner part of the joint body and extends in the whole axial length range of the joint body, the pipe connecting part comprises an equal diameter part and an expanded diameter part with the outer diameter gradually increasing from the tail end to the equal diameter part, the equal diameter part is cylindrical and is formed at the tail end of the external thread part, the expanded diameter part is formed at the tail end of the equal diameter part, the nut comprises an internal thread part and a through hole, and the internal thread part is matched and screwed with the external thread part, and the pipe joint is characterized in that:
the diameter expanding part comprises a first diameter expanding part and a second diameter expanding part, the second diameter expanding part is formed at the tail end of the first diameter expanding part, the outer surface of the first diameter expanding part is a part of a spherical surface, and the outer surface of the second diameter expanding part is a part of a conical surface;
the first diameter-expanding portion is gradually reduced in outer diameter from the starting end to the tail end, the second diameter-expanding portion is reduced in diameter from the starting end to the tail end, and the overall outer diameter of the second diameter-expanding portion is smaller than that of the first diameter-expanding portion.
2. A pipe joint according to claim 1, wherein the ratio of the axial length of the second enlarged diameter portion to the axial length of the first enlarged diameter portion is 0.4 to 3.
3. A pipe joint according to claim 1 or 2, wherein the outer diameter of the constant diameter portion is 1.2 to 2 times the outer diameter of the end of the second enlarged diameter portion.
4. A pipe joint according to claim 3, wherein the tip end of the second enlarged diameter portion has the same inner diameter and outer diameter.
5. A pipe joint according to claim 1 or 2, wherein the angle between the outer surface of the second enlarged diameter portion and the axis of the joint body is 35 ° to 55 °.
6. A pipe joint according to claim 1, wherein a starting end of an outer surface of the second enlarged diameter portion and a terminal end of an outer surface of the constant diameter portion are respectively tangent to both ends of an outer surface of the first enlarged diameter portion.
7. A pipe joint according to claim 1, wherein the inner diameter of the through hole is larger than the outer diameter of the end of the second enlarged diameter portion and smaller than the outer diameter of the start end of the second enlarged diameter portion, and the pressing portion is formed outside the through hole.
8. A pipe joint according to claim 7, wherein a spacer is provided between the female screw portion of the nut and the pressing portion, and an inner surface of the spacer is a smooth cylindrical surface.
9. A pipe fitting according to claim 8, wherein the distance between the inner surface of the spacer portion and the axis of the nut is less than the distance between the internally threaded portion and the axis of the nut.
10. A pipe joint according to claim 9, wherein the pipe comprises a large diameter portion and a variable diameter portion after the joint body, the nut and the pipe are assembled, and a gap is left between an inner surface of the spacer and an outer surface of the large diameter portion of the pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921815979.2U CN211010248U (en) | 2019-10-26 | 2019-10-26 | Pipe joint connected with pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921815979.2U CN211010248U (en) | 2019-10-26 | 2019-10-26 | Pipe joint connected with pipe |
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| Publication Number | Publication Date |
|---|---|
| CN211010248U true CN211010248U (en) | 2020-07-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921815979.2U Active CN211010248U (en) | 2019-10-26 | 2019-10-26 | Pipe joint connected with pipe |
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| Country | Link |
|---|---|
| CN (1) | CN211010248U (en) |
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