Nut with anti-splitting thread end for fluid joint assembly

Abstract

A fluid connector assembly and a nut for connecting fluid conduits in the connector assembly are disclosed. The nut includes a nut body having an inner body surface, the inner body surface forming a through-hole to support a first fluid conduit and a second fluid conduit. An internal thread on the inner body surface advances in a helical path around the nut's central axis between a thread start point and a thread end point, the thread end point being located between a first axial end face and a second axial end face of the nut body. At least one of the thread end point and the thread start point is located within a thickness-increasing region formed by the varying radial thickness of the nut. The nut reduces the risk of cracking during use.

Description

Technical Field

[0001] This disclosure generally relates to fluid connector assemblies, and more specifically to nuts for connecting fluid conduits in fluid connector assemblies, the nuts having internal threads that begin or terminate at a crack-resistant location in the nut. Background Technology

[0002] Various industries require powerful equipment for fluid handling, particularly the oil and gas industry, where fluid hydrocarbon materials and liquids used to extract such materials are pumped and transported under high fluid pressure. For example, hydraulic fracturing typically involves pumping up the pressure of fracturing fluid and injecting the highly pressurized fluid into underground formations to fracture the underlying rock. Concrete dumping, gas compression, and other fluid transport applications similarly involve the pressurization and transport of highly viscous and / or highly pressurized fluids. The conduits used in these applications, typically metal pipes, are designed to withstand high absolute pressures, cyclic loads, and other harsh conditions. In these applications, the hardware used to connect pipes, etc., is typically designed for high failure resistance. Threaded nuts, often equipped with protruding rings or lugs, are used to connect adjacent pipe sections, where the rings or lugs provide contact surfaces for manually operated tools (such as sledgehammers) or hydraulically operated tools, enabling the application of tightening or removal of the required load.

[0003] The harsh conditions in these and other applications can limit the service life of nuts and related components. In addition to the stresses generated by fluid transport, applying loads to tighten or loosen the nut can itself introduce or exacerbate the risk of failure. For these reasons, engineers are constantly seeking improvements to combat fatigue or impact-induced cracking, among other things. An exemplary design for a wing nut used in fluid transport applications is known from Witkowski's WIPO Publication No. 2016 / 205208. Summary of the Invention

[0004] In one aspect, a fluid connector assembly includes: a fluid conduit having an inner conduit surface defining a conduit central axis extending between a first axial conduit end and a second axial conduit end. The fluid connector assembly further includes a nut for connecting the fluid conduit to a second fluid conduit, and includes a nut body having an outer body surface and an inner body surface. The inner body surface defines the nut central axis and forms a through-hole extending between a first axial end face and a second axial end face. The fluid connector assembly also includes an internal thread formed on the inner body surface and advanced in a helical path around the nut central axis between a thread start point and a thread end point, the thread end point being located between the first axial end face and the second axial end face. The outer body surface has a tool engagement profile such that the radial thickness of the nut body varies, forming a plurality of thickness decreasing regions circumferentially around the nut central axis in an alternating pattern with a plurality of thickness increasing regions. At least one of the thread start point or the thread end point is located within one of the plurality of thickness increasing regions.

[0005] In another aspect, a nut for connecting fluid conduits in a connector assembly includes a nut body having an outer body surface and an inner body surface, the inner body surface defining a nut central axis extending between a first axial end face and a second axial end face of the nut body. The inner body surface forms a through-hole for end-to-end arrangement of supporting a first fluid conduit and a second fluid conduit, and the inner body surface includes an internal thread advancing in a helical path around the helical central axis between a thread start point and a thread end point, the thread end point being located between the first and second axial end faces. The outer body surface includes a tool engagement profile such that the radial thickness of the nut body varies, forming a plurality of thickness decreasing regions circumferentially around the nut central axis in an alternating pattern of multiple thickness increasing regions. The thread end point is located within one of the plurality of thickness increasing regions.

[0006] In another aspect, a nut for connecting fluid conduits in a connector assembly includes a nut body having an outer body surface and an inner body surface, the inner body surface defining a nut central axis extending between a first axial end face and a second axial end face of the nut body. The inner body surface forms a through-hole for end-to-end arrangement of supporting a first fluid conduit and a second fluid conduit, and the inner body surface includes an internal thread advanced in a helical path around the nut central axis between a thread start point and a thread end point. The outer body surface includes a plurality of circumferential transition surfaces arranged alternately with a plurality of outer surfaces, the plurality of outer surfaces being radially outwardly spaced relative to the plurality of circumferential transition surfaces. The material thickness of the nut body varies between a thickness-decreasing region and a thickness-increasing region based on the radially outward spacing of the plurality of outer surfaces, such that the crack susceptibility of the nut body varies adaptively with the variation in material thickness. At least one of the thread start point or the thread end point is located within one of the thickness-increasing regions. Attached Figure Description

[0007] Figure 1 This is a cross-sectional diagram of a fluid connector assembly according to one embodiment in two cross-sectional planes;

[0008] Figure 2 This is a top front view of a nut according to one embodiment;

[0009] Figure 3 It is along Figure 2 A cross-sectional view taken from line 3-3;

[0010] Figure 4 yes Figure 2 An isometric view of the nut;

[0011] Figure 5 It is shown as follows Figure 2-4 A detailed view of a portion of the nut; and

[0012] Figure 6 This is an isometric view of a nut according to another embodiment. Detailed Implementation

[0013] refer to Figure 1A fluid connector assembly 10 according to one embodiment is shown. The fluid connector assembly 10 includes a first fluid conduit 12 having an inner conduit surface 16 defining a conduit central axis 20 extending between a first axial conduit end 22 and a second axial conduit end 24. The fluid connector assembly 10 may further include a second fluid conduit 14 having an inner conduit surface 18. Internal threads 26 and 28 are formed on the inner conduit surface 16 and 18, respectively. The first fluid conduit 12 and the second fluid conduit 14 are arranged end-to-end in the fluid connector assembly 10, and a sealing sleeve 30 is axially positioned between the first fluid conduit 12 and the second fluid conduit 14. The fluid connector assembly 10 also includes a nut 32 for connecting the first fluid conduit 12 to the second fluid conduit 14, the nut having a nut body 34 having an outer body surface 36 and an inner body surface 38. The inner body surface 38 defines the nut's central axis 40 and forms a through hole 42 extending between a first axial end face 44 and a second axial end face 46 of the nut body 34 for end-to-end support of the first fluid conduit 12 and the second fluid conduit 14. The fluid connector assembly 10 can be deployed in any of a variety of pumping and / or fluid transfer applications and is envisioned to provide advantages, particularly in high-pressure applications such as fluid pressurization or transmission in the oil and gas industry, but this disclosure is not limited thereto. As will further become apparent from the following description, the fluid connector assembly 10 is expected to have increased crack resistance compared to certain known strategies.

[0014] In the illustrated embodiment, the first fluid conduit 12 includes an internal thread 26 configured to attach the first fluid conduit 12 to another input or output fluid conduit, and the second fluid conduit 14 includes an internal thread 28 for connection to another input or output fluid conduit. Either the first fluid conduit 12 or the second fluid conduit 14 can be fluidly connected to a pumping mechanism, pressure vessel, valve, or other fluid handling equipment. Furthermore, one or both of the first fluid conduit 12 and the second fluid conduit 14 may include external threads to complement or replace the illustrated internal threads for connection with… Figure 1 Additional equipment connections are not shown. For this attachment purpose, other connection mechanisms, such as flanges, may be provided on the first fluid conduit 12 and the second fluid conduit 14. As used herein, the plural term "thread" should be understood to mean a single thread or multiple threads.

[0015] The nut 32 also includes an internal thread 48 formed on the inner body surface 38 and advancing in a helical path about the nut's central axis 40 between a thread start point 56 and a thread end point 58, the thread end point being located between a first axial end face 44 and a second axial end face 46. The thread end point 58 may include the endpoint of a thread valley formed in the inner body surface 38, but in other embodiments may include the endpoint of a thread peak or ridge. Reference is also made to... Figure 2-4 The outer body surface 36 has a tool engagement profile such that the radial thickness of the nut body 34 varies, forming a plurality of thickness reduction regions 60 circumferentially around the nut central axis 40 in an alternating pattern with a plurality of thickness increase regions 64. The thickness reduction regions 60 may define a reduced radial thickness 62, and the thickness increase regions 64 may define an increased radial thickness 66. The reduced radial thickness 62 may be approximately 50% of the increased radial thickness 66, and more broadly, it may be approximately 25% to approximately 75% of the increased radial thickness 66. However, this disclosure is not limited in this respect, and those skilled in the art will contemplate various other configurations of the tool engagement profile having relatively large or relatively small variations or different patterns of variation in radial thickness. The circular outer surface profile should not be construed as a tool engagement profile as contemplated herein. At least one of the thread start point 56 or thread end point 58 is located within one of the plurality of thickness increase regions 64, and in the illustrated embodiment, the thread end point 58 is located within one of the plurality of thickness increase regions 64, and the thread start point 56 is located within one of the plurality of thickness reduction regions 60.

[0016] Also in the illustrated embodiment, the nut body 34 includes a plurality of tool-beating wings 68 forming a plurality of thickness-increasing regions 64. Each of the tool-beating wings 68 may include an outer wing surface 76 facing radially outward, and a pair of striking surfaces 78 extending inward from the respective outer wing surface 76, such that each of the plurality of tool-beating wings 68 forms a trapezoidal profile. Other profiles may be used, such as square, rectangular, leaf-shaped, triangular, or other profiles. During the assembly or installation of the fluid connector assembly 10, a technician may use a hand hammer or sledgehammer, hydraulic hammer, hydraulic wrench, or other suitable tool to contact the striking surfaces 78 to rotate the nut 32 about the nut central axis 40 and press the first fluid conduit 12 and the second fluid conduit 14 together, compress the sealing sleeve 30 in use, and additionally clamp the first fluid conduit 12 and the second fluid conduit 14 axially together in an end-to-end arrangement. For disassembly or assembly, a technician may appropriately apply impact or other rotational loads to one or more of the striking surfaces 78 in a generally opposite manner.

[0017] like Figure 3 As shown, the nut body 34 may have an axial body thickness 70 extending between a first axial end face 44 and a second axial end face 46. Each of the plurality of tool striking wings 68 may have an axial wing thickness 72 that is less than the axial body thickness 70. Figure 3The diagram also shows a spacing 73 from the thread endpoint 58 to the second axial end face 46. The spacing 73 may be less than the axial flange thickness 72. The approximate axial position of the thread endpoint 58 may be at the longitudinal midpoint between the first axial end face 44 and the second axial end face 46; however, this disclosure is not limited in this respect. The nut body 34 may also include a radially inwardly projecting inner clamping shoulder 52. Figure 1 As can be seen, the first fluid conduit 12 includes an outer clamping shoulder 54 that contacts the inner clamping shoulder 52. The second fluid conduit 14 includes an outer thread 50 that engages with the internal thread 48. This disclosure contemplates any suitable arrangement of the shoulders and threads on the first fluid conduit 12, the second fluid conduit 14, and the nut 32, such that the nut 32 can be rotated about the nut central axis 40 to increase or decrease the clamping force on the first fluid conduit 12 and the second fluid conduit 14. A threadless inner bore surface 74 extends axially between the inner clamping shoulder 52 and the thread end point 58. The threadless inner bore surface 74 may include an inward stepped profile between the thread end point 58 and the second axial end face 46 to form the inner clamping shoulder 52.

[0018] It is also envisioned that the threads on the nut body 34 can have any suitable thread configuration. In a practical implementation, the internal thread 48 includes a thread peak 80 and a thread valley 82. It should be remembered that the internal thread 48 can include, and typically includes, a single continuous thread. Therefore, the thread peak 80 can include a single continuous peak, and the thread valley 82 can include a single continuous valley. The internal thread 48 is arcuate, such that in the illustrated embodiment, the thread valley 82 is as follows in its longitudinal profile... Figure 3 The curve depicted herein may be trapezoidal, square, or another shape in other embodiments. The thread peak 80 may be square to have a linear longitudinal profile.

[0019] The outer body surface 36 can also be understood to include a plurality of circumferential transition surfaces 84 arranged alternately with the plurality of outer wing surfaces 76. The outer wing surfaces 76 are radially outwardly spaced relative to the plurality of circumferential transition surfaces 84. In some embodiments, each of the circumferential transition surfaces 84 may form a radially projecting circumferential rib 85 extending circumferentially between adjacent wings of the tool striking wing 68, such as Figure 4As depicted in the diagram. The nut body 34 may be formed from a metallic material such as forged or cast iron or steel, wherein the material thickness of the nut body 34 varies between a thickness-reducing region 60 and a thickness-increasing region 64 based on the radially outward spacing of a plurality of outer flanges 76. Based on the varying material thickness, the crack susceptibility of the nut body 34 adapts accordingly to the variation in material thickness. This principle can be understood to mean that the susceptibility of the nut body 34 to cracking may be relatively high in the thickness-reducing region 60 and relatively low in the thickness-increasing region 64. By properly positioning the thread end point 58, and in some embodiments positioning the thread start point 56, the crack resistance of the nut 32 during use or during the assembly or disassembly of the fluid connector assembly 10 can be reduced compared to known designs.

[0020] In one embodiment, the thread endpoint 58 is substantially aligned circumferentially with the longitudinal centerline 65 of one of the plurality of outer wing surfaces 76, such as Figure 2 As shown in the illustration. Other embodiments may include different alignments of the thread endpoint 58 with respect to the longitudinal centerline of the outer flange 76. In the illustrated embodiment, the tool-beating flange 68 is generally circumferentially symmetrical about the nut's central axis 40. In other embodiments, the tool-beating flange 68 may have an asymmetrical configuration, and based on the shape of the tool-beating flange 68, the thread endpoint 58 may be displaced to a location where relatively more material is available for crack resistance. Other nut configurations can demonstrate that the thread endpoint 58 can be positioned at other relative locations not only based on the nut's structure but also based on the expected loads experienced during use or during assembly or disassembly. In the illustrated embodiment, the thread endpoint 58 is centered circumferentially within one of the thickness-increase regions 64. The thread endpoint 58 may also be longitudinally centered between the first axial end face 44 and the second axial end face 46. The nut body 34 may also have a total of three tool-beating flanges, each including an outer flange 76 and two striking faces 78. In other embodiments, a total of two striking flanges, or more than three striking flanges, may be provided.

[0021] Now for reference Figure 5A detailed view of the nut 32 is shown, illustrating the location of the thread endpoint 58 compared to the thread endpoint location 158 observable in known nuts. It can be seen that the known thread endpoint location 158 should be understood as residing in a region of decreasing thickness, while the thread endpoint 58 is in a region of increasing thickness. It can also be noted that the thread endpoint 58 is formed adjacent to the unthreaded inner bore surface 74. It has been observed that the geometric transition between the threaded area and the unthreaded area can be associated with stress concentration. Axial loads, bending loads imparted by bending forces on fluid conduits connected in use, or other factors can cause the thread endpoint location to act as a crack initiation and propagation point, typically in the radially outward direction through the material of the nut. It should be understood that in the case of nuts employing thread endpoint 158, less material is present in the radially outward direction to diffuse or otherwise accommodate stress, whereas in the case of this disclosure, a greater amount of material in the radially outward direction allows for greater stress diffusion and management, and a reduced risk of crack initiation and propagation.

[0022] Turning Figure 6 The illustration shows a nut 232 according to another embodiment, comprising a nut body 234 having internal threads 248 configured to clamp fluid conduits together in an end-to-end arrangement similar to the foregoing embodiments. The nut 232 includes a plurality of tool-beating wings 268, again generally similar to the foregoing embodiments, and producing an increasing material thickness alternating with decreasing material thickness. The nut 232 differs from the foregoing embodiments in that both the thread start point 256 and the thread end point 258 are aligned with one of the tool-beating wings 268, and are thus formed in the region of increasing thickness of the nut body 234. In alternative embodiments, only the thread start point 256 may be located within the region of increasing thickness, or the thread start point 256 and the thread end point 258 may each be located within a region of increasing thickness, but in different regions than each other. Unless otherwise indicated or apparent from the context, the description of any embodiment herein should be understood to refer to any other embodiment by analogy.

[0023] Industrial applicability

[0024] Referring generally to the accompanying drawings, during the installation and assembly of the fluid connector assembly 10, the first fluid conduit 12 is slidable through the through-hole 42 until the outer clamping shoulder 54 and the inner clamping shoulder 52 come into contact with each other to establish the relative axial position of the first fluid conduit 12 and the nut 32. Then, for example by engaging the external thread 50 with the internal thread 48 and rotating the nut 32 until the respective axial ends of the fluid conduit 12 and the second fluid conduit 14 abut each other, the second fluid conduit 14 can be engaged with the nut 32.

[0025] Then, the nut 32 can be further rotated, for example by striking one or more of the wings 68 with a striking tool to axially clamp the first fluid conduit 12 and the second fluid conduit 14 together. During use, the fluid connector assembly 10 is expected to experience, for example, high circulating pressures from fluid pumping, and can also deliver fluids with relatively high viscosity. The so-called pull-out force concentrated at the thread end 58 will generate material stress in the material of the nut 32; however, as discussed herein, the relatively large amount of material based on the location of the thread end 58 can be advantageously managed to prevent cracking or excessive material fatigue.

[0026] This specification is for illustrative purposes only and should not be construed as limiting the scope of this disclosure in any way. Therefore, those skilled in the art will recognize that various modifications can be made to the embodiments disclosed herein without departing from the full and reasonable scope and spirit of this disclosure. Other aspects, features, and advantages will become apparent from the accompanying drawings and claims. As used herein, the articles “a” and “an” are intended to include one or more articles and are interchangeable with “one or more”. The term “one” or similar language is used when it is desired to indicate that there is only one article. Furthermore, as used herein, the terms “has,” “have,” “having,” etc., are intended to be open-ended terms. Additionally, the phrase “based on” is intended to mean “at least partially based on” unless otherwise expressly stated.

Claims

1. A fluid connector assembly, comprising: A first fluid conduit, the first fluid conduit including an inner conduit surface defining a conduit central axis extending between a first axial conduit end and a second axial conduit end; A nut for connecting a first fluid conduit to a second fluid conduit, and comprising a nut body having an outer body surface and an inner body surface, the inner body surface defining a nut central axis and forming a through hole extending between a first axial end face and a second axial end face; An internal thread is formed on the surface of the inner body and advances in a helical path around the central axis of the nut between the thread start point and the thread end point, the thread end point being located between the first axial end face and the second axial end face; The outer body surface has a tool engagement profile, causing the radial thickness of the nut body to vary, forming multiple thickness-decreasing regions circumferentially around the central axis of the nut in an alternating pattern with multiple thickness-increasing regions; and At least one of the thread start point or the thread end point is located within one of the plurality of thickness increase regions.

2. The fluid connector assembly according to claim 1, wherein: The nut body includes multiple tool striking wings that form the multiple thickness-increased regions; The nut body has an axial body thickness extending between the first axial end face and the second axial end face; Each of the plurality of tool striking wings has an axial wing thickness less than the axial body thickness; The thread endpoint is located within one of the plurality of thickness-increasing regions; The nut body also includes an inner clamping shoulder, and the unthreaded inner bore surface extends axially between the inner clamping shoulder and the end of the thread; and The first fluid conduit includes an outer clamping shoulder that contacts the inner clamping shoulder.

3. The fluid connector assembly according to claim 1 or 2 further includes a second fluid conduit supported in the through hole, and the second fluid conduit includes an external thread that engages with the internal thread to clamp the first fluid conduit in end-to-end contact with the second fluid conduit.

4. A nut for connecting a fluid conduit in a connector assembly, the nut comprising: A nut body having an outer body surface and an inner body surface, the inner body surface defining a nut central axis extending between a first axial end face and a second axial end face of the nut body; The inner body surface forms a through hole for arranging support for the first fluid conduit and the second fluid conduit end-to-end, and the inner body surface includes an internal thread that advances in a helical path around the central axis of the nut between the thread start point and the thread end point, the thread end point being located between the first axial end face and the second axial end face; The outer body surface has a tool engagement profile, causing the radial thickness of the nut body to vary, forming multiple thickness-decreasing regions circumferentially around the central axis of the nut in an alternating pattern with multiple thickness-increasing regions; and The thread endpoint is located within one of the plurality of thickness-increasing regions.

5. The nut according to claim 4, wherein: The nut body includes multiple tool striking wings that form the multiple thickness-increased regions; The internal thread is arc-shaped in its longitudinal profile, and the thread endpoint includes the endpoint of a thread valley formed in the surface of the inner body. Each of the plurality of tool striking wings includes an outer wing surface facing radially outward and a pair of striking surfaces extending inward from the corresponding outer wing surface, such that each of the plurality of tool striking wings forms a trapezoidal profile. The inner body surface includes an unthreaded inner bore surface extending axially between the thread endpoint and the second axial end face of the nut body; and The end point of the thread is substantially aligned circumferentially with the longitudinal centerline of one of the plurality of outer surfaces.

6. The nut of claim 5, wherein the unthreaded inner bore surface has an inward stepped profile between the thread end point and the second axial end face to form an inner clamping shoulder.

7. A nut for connecting a fluid conduit in a connector assembly, the nut comprising: A nut body having an outer body surface and an inner body surface, the inner body surface defining a nut central axis extending between a first axial end face and a second axial end face of the nut body; The inner body surface forms a through hole for arranging support for the first fluid conduit and the second fluid conduit end-to-end, and the inner body surface includes an internal thread that advances in a helical path around the central axis of the nut between the thread start point and the thread end point. The outer body surface includes a plurality of circumferential transition surfaces arranged alternately with a plurality of external surfaces, the plurality of external surfaces being radially spaced outward relative to the plurality of circumferential transition surfaces; The material thickness of the nut body varies between regions of decreasing and increasing thickness based on the radial outward spacing of the plurality of external surfaces, such that the crack sensitivity of the nut body adapts to the variation in material thickness; and At least one of the thread start point or the thread end point is located within one of the thickness increase regions.

8. The nut of claim 7, wherein the nut body further comprises a plurality of tool striking surfaces, each tool striking surface extending between one of the plurality of circumferential transition surfaces and one of the plurality of outer surfaces.

9. The nut according to claim 8, wherein: The inner body surface includes an unthreaded inner bore surface extending axially between the thread end point and the second axial end face of the nut body; The nut body includes a total of three tool-beating wings, each tool-beating wing comprising one of the plurality of outer surfaces and two of the plurality of tool-beating surfaces; and The thread endpoint is centered in one of the plurality of thickness-increasing regions in the circumferential direction.

10. The nut of claim 9, wherein the unthreaded inner bore surface has an inward stepped profile between the thread end point and the second axial end face to form an inner clamping shoulder.

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