Fittings for joining lengths of pipe by a press-fit connection and pipe assembly formed using same

Abstract

A pipe assembly is provided, comprising: a male fitting having a radially inner side and outer side; at least one standard tooth extending about the radially outer side, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction; a biased tooth extending circumferentially about the radially outer side, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction by an angle A1; and a female fitting having a radially inner side and outer side; at least one standard tooth extending about the radially inner side, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction; a biased tooth extending circumferentially about the radially inner side, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction by the angle A1.

Description

FITTINGS FOR JOINING LENGTHS OF PIPE BY A PRESS-FIT CONNECTION AND PIPE ASSEMBLY FORMED USING SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Patent Application No. 63 / 478,722 filed on January 6, 2023, and U.S. Provisional Patent Application No. 63 / 584,926 filed on September 25, 2023, each of which is incorporated by reference herein in its entirety.BACKGROUND

[0002] When creating a pipeline, whether horizontally or vertically, and whether underground or above ground, one typically assembles consecutive lengths of pipe one after the other. Often, pipelines are formed by driving a first section of pipe axially into position, fixing a second length of pipe to the first, driving the joined first and second sections of pipe axially into position, adding a third length, and so on. Two examples of such pipeline formation may include auger boring and micro tunneling.

[0003] Traditionally, individual lengths of pipe used in forming a pipeline are arranged in a line, end-to-end, with each being welded to the next as individual lengths of pipe are added to the pipeline. However, welding the individual lengths of pipe to one another, particularly in the field, is a time-consuming process involving additional danger, high heat, skilled welding personnel, time to allow welds to cool, and possible imperfections in the finished product that may lead to leaking or diminished structural integrity.

[0004] Press-fitting pipes together, where a first pipe with a male end is joined to a second pipe with a female end, is a possible alternative to welding. However, press-fitting lengths of pipe together creates additional challenges, including the great forces / pressures that are required to cause pipes, which may be made of steel or other metals, to deform enough to engage one another in a press-fit fashion. Additionally, press-fitting lengths of pipe to one another using currently-available press-fittings requires precise alignment of the pipes. Where two pipes are not perfectly aligned when pressure is applied to press-fit them together, the pipes may “buck” (that is, bend relative to one another at the union point) which may damage the pipes and / or equipment used to handle and join the pipes.

[0005] Furthermore, depending upon the application of the pipeline, the press-fit unions of lengths of pipes have to undergo great forces without separating or failing. Particularly, where pipelines are oriented horizontally, the lengths of pipes and thus the unions between the pipes,experience great compressive stresses during installation. Where pipelines are oriented vertically, the lengths of pipes and thus the unions between the pipes experience both compressive stresses as well as bending stresses. Thus, it is important that once lengths of pipe are press-fit together, they are not capable of being separated without destruction of one or both.

[0006] Accordingly, what is needed is a press-fit pipe connection that requires less force / pressure to join corresponding lengths of pipe, while being able to withstand the compressive and bending stresses that the pipes will experience both during installation and operation in the field.SUMMARY

[0007] In one aspect, a pipe assembly is provided, the pipe assembly comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by the angle Al.

[0008] In another aspect, a pipe assembly is provided, the pipe assembly comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extendingcircumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; and at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by the angle Al, wherein the angle Al is between 18 degrees and 26 degrees.

[0009] In another aspect, a pipe assembly is provided, the pipe assembly comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al, wherein the male fitting biased tooth biased engagement surface is biased in a proximal direction of the male fitting; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; and at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al, wherein the female fitting biased tooth biased engagement surface is biased in a proximal direction of the female fitting.BRIEF DESCRIPTION OF THE FIGURES

[0010] The accompanying figures, which are incorporated in and constitute a part of the specification, illustrate various example embodiments, and are used merely to illustrate various example embodiments. In the figures, like elements bear like reference numerals.

[0011] FIG. 1A illustrates an elevational view of a pipe assembly 100, including a female fitting 102 and a male fitting 104.

[0012] FIG. IB illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0013] FIG. 1C illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0014] FIG. ID illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0015] FIG. IE illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0016] FIG. IF illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0017] FIG. 1G illustrates a partial sectional view of pipe assembly 100, including female fitting 102 and male fitting 104.

[0018] FIG. 2A illustrates an elevational view of a pipe assembly 200, including a female fitting 102 and a drive ring 220.

[0019] FIG. 2B illustrates a partial sectional view of pipe assembly 200, including female fitting 102 and drive ring 220.

[0020] FIG. 2C illustrates a partial sectional view of pipe assembly 200, including female fitting 102 and drive ring 220.

[0021] FIG. 2D illustrates a partial sectional view of pipe assembly 200, including female fitting 102 and drive ring 220.

[0022] FIG. 3A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting.

[0023] FIG. 3B illustrates a partial sectional view of a pipe assembly, including a female fitting and a male fitting.

[0024] FIG. 3C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0025] FIG. 3D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0026] FIG. 3E illustrates a male fitting.

[0027] FIG. 3F illustrates a partial sectional view of a male fitting.

[0028] FIG. 3G illustrates a partial sectional view of a male fitting.

[0029] FIG. 3H illustrates a female fitting.

[0030] FIG. 31 illustrates a partial sectional view of a female fitting.

[0031] FIG. 3J illustrates a partial sectional view of a female fitting.

[0032] FIG. 4A illustrates a drive ring.

[0033] FIG. 4B illustrates a partial sectional view of a drive ring.

[0034] FIG. 5A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one bevel for fixing the female and male fittings to one another.

[0035] FIG. 5B illustrates a partial sectional view of a pipe assembly, including a female fitting and a male fitting, the male fitting including at least one bevel.

[0036] FIG. 5C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0037] FIG. 5D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0038] FIG. 5E illustrates a partial plan view of a pipe assembly, including a bevel oriented on the male fitting to accept a weld.

[0039] FIG. 5F illustrates a male fitting including at least one bevel.

[0040] FIG. 5G illustrates a partial sectional view of a male fitting including at least one bevel.

[0041] FIG. 5H illustrates a partial sectional view of a male fitting including at least one bevel.

[0042] FIG. 51 illustrates a partial plan view of a bevel on a male fitting.

[0043] FIG. 5J illustrates a partial sectional view of a bevel on a male fitting including at least one bevel.

[0044] FIG. 6A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one slot for fixing the female and male fittings to one another.

[0045] FIG. 6B illustrates partial sectional views of a pipe assembly, including a female fitting and a male fitting, the female fitting including at least one slot.

[0046] FIG. 6C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0047] FIG. 6D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0048] FIG. 6E illustrates a partial plan view of a pipe assembly, including a slot oriented on the female fitting to accept a weld.

[0049] FIG. 6F illustrates a female fitting including at least one slot.

[0050] FIG. 6G illustrates a partial plan view of a slot on a female fitting.

[0051] FIG. 6H illustrates a partial sectional view of a female fitting including at least one slot.

[0052] FIG. 61 illustrates a partial sectional view of a female fitting including at least one slot.

[0053] FIG. 7A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one strap for fixing the female and male fittings to one another.

[0054] FIG. 7B illustrates a partial sectional view of a pipe assembly, including a female fitting and a male fitting, including at least one strap.

[0055] FIG. 7C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0056] FIG. 7D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0057] FIG. 7E illustrates a partial plan view of a pipe assembly, including a strap extending from the female fitting to the male fitting.

[0058] FIG. 8 illustrates a perspective view of a pipe assembly 800, including a female fitting 102 and a male fitting 104.

[0059] FIG. 9A illustrates an elevation view of a pipe assembly 900, including female fitting 902 and male fitting 904.

[0060] FIG. 9B illustrates a partial sectional view of pipe assembly 900, including female fitting 902 and male fitting 904.

[0061] FIG. 10A illustrates an elevation view of a pipe assembly 1000, including female fitting 1002 and male fitting 1004.

[0062] FIG. 10B illustrates a partial sectional view of pipe assembly 1000, including female fitting 1002 and male fitting 1004.

[0063] FIG. 10C illustrates a partial sectional view of pipe assembly 1000, including a standard tooth 1030.

[0064] FIG. 10D illustrates a partial sectional view of pipe assembly 1000, including a biased tooth 1039.

[0065] FIG. 11A illustrates an elevation view of a pipe assembly 1100, including female fitting 1102 and male fitting 1104.

[0066] FIG. 11B illustrates a partial sectional view of pipe assembly 1100, including female fitting 1102 and male fitting 1104.

[0067] FIG. 11C illustrates a partial sectional view of pipe assembly 1100, including a standard tooth 1130.

[0068] FIG. 11D illustrates a partial sectional view of pipe assembly 1100, including a biased tooth 1139.

[0069] FIG. 12A illustrates an elevation view of a pipe assembly 1200, including female fitting 1202 and male fitting 1204.

[0070] FIG. 12B illustrates a partial sectional view of pipe assembly 1200, including female fitting 1202 and male fitting 1204.

[0071] FIG. 13 illustrates a perspective view of a pipe assembly 1300, including a female fitting 1302 and a male fitting 1304.

[0072] FIG. 14A illustrates a partial sectional view of a pipe assembly 1400, including a female fitting 1402 and a male fitting 1404.

[0073] FIG. 14B illustrates a partial sectional view of pipe assembly 1400, including a standard tooth in a female fitting and a male fitting.

[0074] FIG. 14C illustrates a female fitting 1402.

[0075] FIG. 14D illustrates a male fitting 1404.

[0076] FIG. 14E illustrates a partial sectional view of male fitting 1404.

[0077] FIG. 14F illustrates a partial sectional view of a male fitting 1404.

[0078] FIG. 14G illustrates a partial sectional view of a female fitting 1402.

[0079] FIG. 14H illustrates a partial sectional view of a female fitting 1402.DETAILED DESCRIPTION

[0080] FIGS. 1A-1G illustrate a pipe assembly 100, including a female fitting 102 and a male fitting 104 at a junction 106.

[0081] As used throughout this application, the radial direction refers to direction R as illustrated in the drawings. Radially outer or radially outwardly refers to the direction R as the radius is increased, whereas radially inner or radially inwardly refers to the direction R as the radius is decreased. As used throughout this application, the axial direction refers to that extending along or parallel to direction A. The axial direction A is intended to extend along thelongitudinal length of a pipe assembly. As used throughout this application, the circumferential direction refers to a direction C, which extends about the circumference of the pipe assembly in a plane orthogonal to the axial direction A, and parallel to the radial direction R.

[0082] Female fitting 102 may include an annular portion of pipe having a radially inner side and a radially outer side. The radially inner side of female fitting 102 includes cavities at its distal end.

[0083] Male fitting 104 may include an annular portion of pipe having a radially inner side and a radially outer side. The radially outer side of male fitting 104 includes teeth at its distal end, corresponding to those of female fitting 102, as will be further described below.

[0084] At least one of female fitting 102 and male fitting 104 may be formed independently of a length of pipe, and may welded or otherwise mechanically fixed to the length of pipe at a proximal end of female fitting 102 and / or male fitting 104. This welding or mechanical attachment of female fitting 102 and / or male fitting 104 to a length of pipe may be performed away from the site of installation of the pipe, or on the site of installation of the pipe.

[0085] Alternatively, at least one of female fitting 102 and male fitting 104 may be machined directly into the ends of a length of pipe. The machining of female fitting 102 and male fitting 104 may be performed using known machining techniques.

[0086] While the drawings focus on the fittings fixing lengths of pipe to one another, rather than the lengths of pipe themselves, it is understood that the fittings are oriented at the ends of a length of pipe. In practice, a single length of pipe may include female fitting 102 at a first end, and male fitting 104 at a second end. In this manner, a series of like lengths of pipe may be fit together, with the female end of a first length of pipe engaging the male end of a second length of pipe, while the male end of the first length of pipe engages the female end of a third length of pipe.

[0087] Alternatively, a single length of pipe may include female fitting 102 at both its first ends and second ends, or may include male fitting 104 at both its first ends and second ends. In this manner, the independent lengths of pipe would be either “male” lengths (with male fitting 104 at each end), or “female” lengths (with female fitting 102 at each end). Assembling a pipeline using these lengths of pipe would require alternating between male lengths and female lengths during assembly of the pipeline.

[0088] Female fitting 102 and male fitting 104 may be made of any of a variety of materials, including without limitation, a metal (such as steel), an alloy, a polymer, a composite, and thelike. In order for female fitting 102 and male fitting 104 to deflect enough relative to one another during the press-fitting of the two together, the material may need appropriate elastic qualities.

[0089] Lengths of pipe used in association with female fitting 102 and male fitting 104 may include any of a variety of lengths convenient for manufacture, transport, and assembly.

[0090] Diameters of lengths of pipe used in association with female fitting 102 and male fitting 104, and thus the diameters of female fitting 102 and male fitting 104, can be any of a variety of diameters. For example, the pipe and fittings may have outer diameters between about 6 in. (15 cm) and 127 in. (323 cm). The pipe and fittings may have outer diameters outside of this range as well.

[0091] Female fitting 102 may include at least one standard tooth 110A extending circumferentially about the radially inner side of the annular portion of female fitting 102. Male fitting 104 may include at least one corresponding standard tooth HOB extending circumferentially about the radially outer side of the annular portion of female fitting 102. Tooth 110A and HOB include radial engagement surfaces 111A and 111B, that are parallel to the radial direction R. The term “corresponding” is intended to mean that tooth 110A and HOB engage one another when female fitting 102 and male fitting 104 are engaged with one another.

[0092] Female fitting 102 may include at least one biased tooth 112A extending circumferentially about the radially inner side of the annular portion of female fitting 102. Male fitting 104 may include at least one corresponding biased tooth 112B extending circumferentially about the radially outer side of the annular portion of female fitting 102. Tooth 112A and 112B includes biased engagement surfaces 113A and 113B, that are biased relative to the radial direction R. FIGS. IF and 1G illustrate biased tooth 112A and 112B and biased engagement surfaces 113A and 113B most clearly. Biased engagement surfaces 113A and 113B are biased at an angle Al. Angle Al may be any of a variety of angles, including for example, 22 degrees. Angle Al may be between 20 degrees and 24 degrees. Angle Al may be between 18 degrees and 26 degrees. Angle Al may be between 16 degrees and 28 degrees. Angle Al may be between 14 degrees and 30 degrees. Angle Al may be between 12 degrees and 32 degrees.

[0093] Biased engagement surfaces 113A and 113B are biased toward the proximal direction of the corresponding female fitting 102 and male fitting 104. That is, tooth 112A is biased such that biased engagement surface 113A extends in the proximal direction of femalefitting 102 as engagement surface 113A extends radially away from the body of female fitting 102. Tooth 112B is biased such that biased engagement surface 113B extends in a proximal direction of male fitting 104 engagement surface 113B extends radially away from the body of male fitting 104.

[0094] As illustrated in FIGS. IF and 1G, as female fitting 102 and male fitting 104 are pulled apart from one another (as indicated by the arrows parallel to axial direction A), biased engagement surfaces 113A and 113B are forced into greater engagement with one another (as indicated by the arrows biased relative to radial direction R). In this manner, biased teeth 112A, 112B, as well as female fitting 102 and male fitting 104, avoid deflecting away from one another as female fitting 102 and male fitting 104 are pulled apart from one another (as indicated by the arrows parallel to axial direction A), and instead deflect toward one another.

[0095] The technical effect of this arrangement is that because of the orientation of biased engagement surfaces 113A and 113B, pulling female fitting 102 and male fitting 104 away from one another causes female fitting 102’ s biased tooth 112A to deflect radially inward, and causes male fitting 104’ s biased tooth 112B to deflect radially outward, thus driving biased engagement surfaces 113A and 113B into greater contact with one another. Examples 2 and 3 described below illustrate the benefit of this arrangement in dramatically increasing the strength of junction 106 to resist separation and failure.

[0096] FIGS. 2A-2D illustrate a pipe assembly 200, including a female fitting 102 and a drive ring 220. Female fitting 102 is as described above. Drive ring 220 is similar to male fitting 104, but lacks teeth.

[0097] Drive ring 220 may be used to protect teeth 110A, 112A of female fitting 102. Drive ring 220 may be used to protect teeth 110A, 112A of female fitting 102 during transport and / or handling. Drive ring 220 may be used to protect teeth 110A, 112A of female fitting 102 at a first end of a pipe, while the second of the pipe is press-fit to another corresponding pipe.

[0098] FIG. 3A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting.

[0099] FIG. 3B illustrates partial sectional views of a pipe assembly, including a female fitting and a male fitting. The female and male fittings include both corresponding standard teeth and corresponding biased teeth.

[0100] FIG. 3C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0101] FIG. 3D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0102] FIG. 3E illustrates a male fitting.

[0103] FIG. 3F illustrates a partial sectional view of a male fitting.

[0104] FIG. 3G illustrates a partial sectional view of a male fitting.

[0105] FIG. 3H illustrates a female fitting.

[0106] FIG. 31 illustrates a partial sectional view of a female fitting.

[0107] FIG. 3J illustrates a partial sectional view of a female fitting.

[0108] The various dimensions illustrated in FIGS. 3B-3J are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0109] FIG. 4A illustrates a drive ring.

[0110] FIG. 4B illustrates a partial sectional view of a drive ring. As discussed above, the drive ring is similar to the male fitting, but without any teeth.

[0111] Example 1 - Three Tooth / Cavity Assembly:

[0112] A male fitting having three teeth, and a female fitting having three cavities as described herein were joined to full engagement. The fittings included two standard teeth and one biased tooth with dimensions as described in FIGS. 3A-3J. The fittings had a 36 in. (91.4 cm) diameter. The fittings were machined into A252 grade 3 steel. A 100 ton (890 kN) press was used insert the male fitting into the female fitting until full engagement between the two. The test was performed with two sets of fittings, one using lubrication and one not using lubrication. Pressures, forces, and displacement were measured during the assembly process. The pressures and forces were applied along the axial direction of the fittings. The following table indicates data collected during the assembly process.

[0113] Table 1. Fitting Assembly Forces

[0114] Example 2 - Three Tooth / Cavity Disassembly:

[0115] The male and female fittings of Example 1 were subjected to axial forces pulling the male and female fittings apart from one another, in a direction opposite those forces applied during assembly of the fittings. The fittings included two standard teeth and one biased tooth with dimensions as described in FIGS. 3A-3J. The fittings had a 36 in. (91.4 cm) diameter. The test setup gradually applied greater axial forces to the joint, with a pause of 30 seconds between each increase in the applied axial force. The joint between the assembled male and female fittings failed upon an applied axial force of 647 tons (5,756 kN), which is a force 35-54 times that required to assemble the joint.

[0116] FIG. 5A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one bevel for fixing the female and male fittings to one another. The slot is a machined section (e.g., 1.571 in. wide in the circumferential direction of the male fitting, and 0.250 in. long in the axial direction of the male fitting) at one or more position (e.g., four positions spaced at 90 degrees) of the male fitting.

[0117] The bevel is designed to accept a weld to fix the male fitting in the vicinity of the bevel to the female fitting in the vicinity of the bevel (e.g., a distal face of the female fitting). Welds may assist in providing lateral and / or bending stability to assembled pipes, particularly when the assembled pipes are oriented in a vertical configuration.

[0118] FIG. 5B illustrates a partial sectional view of a pipe assembly, including a female fitting and a male fitting, the male fitting including at least one bevel.

[0119] FIG. 5C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0120] FIG. 5D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0121] FIG. 5E illustrates a partial plan view of a pipe assembly, including a bevel oriented on the male fitting to accept a weld.

[0122] FIG. 5F illustrates a male fitting including at least one bevel.

[0123] FIG. 5G illustrates a partial sectional view of a male fitting including at least one bevel.

[0124] FIG. 5H illustrates a partial sectional view of a male fitting including at least one bevel.

[0125] FIG. 51 illustrates a partial plan view of a bevel on a male fitting.

[0126] FIG. 5J illustrates a partial sectional view of a bevel on a male fitting including at least one bevel.

[0127] The various dimensions illustrated in FIGS. 5B-5J are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0128] Example 3 - Three Tooth / Cavity Disassembly with Four Tack Welds:

[0129] A male fitting having three teeth, and a female fitting having three cavities as described herein were joined to full engagement. The fittings included two standard teeth and one biased tooth with dimensions as described in FIGS. 5A-5J. The fittings included four bevels equally distributed about the circumference of the fittings (i.e., every 90 degrees) having the dimensions described in FIGS. 5E, 51, and 5J. Assembly of the fittings into full engagement required the same forces and pressures described above with respect to Example 1.Each of the four bevels was filled with a tack weld extending between the male and female fittings, 1.571in. (39.903mm) long in the circumferential direction. The fittings had a 36 in. (91.4 cm) diameter. Following full engagement and application of the four tack welds, the joint was exposed to axial forces pulling it back apart as described above in Example 2. The test setup gradually applied greater axial forces to the joint, with a pause of 30 seconds between each increase in the applied axial force. The joint between the assembled male and female fittings failed upon an applied axial force of 681 tons (6,059 kN), which is a force 37-57 times that required to assemble the joint.

[0130] FIG. 6A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one slot for fixing the female and male fittings to one another. The slot is a machined section (e.g., a 1.000 in. wide in the circumferential direction of the female fitting, and 0.375 in. long in the axial direction of the female fitting) at one or more position (e.g., four positions spaced at 90 degrees) of the female fitting. The slot extends completely through the thickness of the female fitting.

[0131] The slot is designed to accept a weld to fix the female fitting in the vicinity of the slot to the male fitting in the vicinity of the slot (e.g., underlying the slot). Welds may assist in providing lateral and / or bending stability to assembled pipes, particularly when the assembled pipes are oriented in a vertical configuration.

[0132] FIG. 6B illustrates partial sectional views of a pipe assembly, including a female fitting and a male fitting, the female fitting including at least one slot.

[0133] FIG. 6C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0134] FIG. 6D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0135] FIG. 6E illustrates a partial plan view of a pipe assembly, including a slot oriented on the female fitting to accept a weld.

[0136] FIG. 6F illustrates a female fitting including at least one slot.

[0137] FIG. 6G illustrates a partial plan view of a slot on a female fitting.

[0138] FIG. 6H illustrates a partial sectional view of a female fitting including at least one slot.

[0139] FIG. 61 illustrates a partial sectional view of a female fitting including at least one slot.

[0140] The various dimensions illustrated in FIGS. 6B-6I are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0141] FIG. 7A illustrates an elevational view of a pipe assembly, including a female fitting and a male fitting, including at least one strap for fixing the female and male fittings to one another.

[0142] The strap is a section of a metal (e.g., a 0.250 in. thick in the radial direction, 2.000 in. wide in the circumferential direction, and 4.000 in. long in the axial direction) at one or more position (e.g., four positions spaced at 90 degrees) of a radially outer surface of the assembled female fitting and male fitting. The strap extends across the junction of the female fitting and the male fitting, such that it engages both the female fitting and the male fitting.

[0143] The strap is designed to be welded to a radially outer surface of the female fitting and a radially outer surface of the male fitting, across the junction between the two. The strap may assist in providing lateral and / or bending stability to assembled pipes, particularly when the assembled pipes are oriented in a vertical configuration.

[0144] FIG. 7B illustrates a partial sectional view of a pipe assembly, including a female fitting and a male fitting, including at least one strap.

[0145] FIG. 7C illustrates a partial sectional view of a pipe assembly, including a standard tooth in a female fitting and a male fitting.

[0146] FIG. 7D illustrates a partial sectional view of a pipe assembly, including a biased tooth in a female fitting and a male fitting.

[0147] FIG. 7E illustrates a partial plan view of a pipe assembly, including a strap extending from the female fitting to the male fitting.

[0148] The various dimensions illustrated in FIGS. 7B-7E are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0149] FIG. 8 illustrates a pipe assembly 800, including a female fitting 802 and a male fitting 804 at a junction 806.

[0150] Female fitting 802 may include lands 814 and grooves 816 alternating circumferentially about an interior surface of female fitting 802 at a terminal end adjacent to junction 806. Lands 814 may extend radially inwardly from an outer surface of female fitting 802 than grooves 816. Grooves 816 may be machined into the thickness of female fitting 802 from the interior surface of female fitting 802, leaving lands 814 as the unmachined portions. Lands 814 may be radially aligned with the remainder of the interior surface of female fitting 802.

[0151] Male fitting 804 may include lands 810 and grooves 812 alternating circumferentially about an exterior surface of male fitting 804 at a terminal end adjacent to junction 806. Lands 810 may extend radially outwardly from an inner surface of male fitting 804 than grooves 812. Grooves 812 may be machined into the thickness of male fitting 804 from the exterior surface of male fitting 804, leaving lands 810 as the unmachined portions. Lands 810 may be radially aligned with the remainder of the exterior surface of male fitting 804.

[0152] Lands 810 are sized, shaped, and spaced to fit into grooves 816, while grooves 812 are sized, shaped, and spaced to accept lands 814. In this manner, male fitting 804 and female fitting 802 are engaged to one another, with lands 810, 814 and grooves 812, 816 preventing rotation of male fitting 804 relative to female fitting 802.

[0153] Female fitting 802 includes at least one aperture 818 extending radially through one or both of land 814 and groove 816. Male fitting 804 includes at least one aperture 820 extending radially through one or both of land 810 and groove 812. Female fitting 802 may include a plurality of apertures 818 circumferentially spaced about female fitting 802. Male fitting 804 may include a plurality of apertures 820 circumferentially spaced about male fitting 804. One or both of aperture 818 and 820 may be threaded. Apertures 818 and 820 are radially aligned with one another when female fitting 802 and male fitting 804 are engaged to one another. A fastener 822 is inserted into and extends through apertures 818 and 820. Fastener 822 may be a bolt, screw, pin, rivet, or the like. Fastener 822 prevent both axial movement and rotation of male fitting 804 relative to female fitting 802. Fastener 822 may be removed when one desires to separate female fitting 802 from male fitting 804.

[0154] FIGS. 9A and 9B illustrate a pipe assembly 900, including female fitting 902 and male fitting 904. Female fitting 902 and male fitting 904 each include a corresponding tooth 930 extending circumferentially about each of female fitting 902 and male fitting 904, whichengage one another to maintain female fitting 902 and male fitting 904 in contact with one another and prevent axial movement of female fitting 902 relative to male fitting 904.

[0155] Female fitting 902 includes a pocket 932 extending circumferentially about the interior of female fitting 902 configured to accept a distal end 934 of male fitting 904. Distal end 934 is sized and shaped to fit into pocket 932. An edge of female fitting 902 forming pocket 932 may overlap a portion of distal end 934.

[0156] Male fitting 904 includes a pocket 938 extending circumferentially about the exterior of male fitting 904 configured to accept a distal end 936 of female fitting 902. Distal end 936 is sized and shaped to fit into pocket 938. An edge of male fitting 904 forming pocket 938 may overlap a portion of distal end 936.

[0157] Engagement of distal ends 934 and 936 with pockets 932 and 938 prevents distal ends 934 and 936 from moving radially such that female fitting 902 and male fitting 904 move radially away from one another. The result is increased strength of pipe assembly 900 under a radial load and / or bending load.

[0158] FIGS. 10A-10D illustrate a pipe assembly 1000, including female fitting 1002 and male fitting 1004.

[0159] Female fitting 1002 and male fitting 1004 each include a corresponding straight tooth 1030 extending circumferentially about each of female fitting 1002 and male fitting 1004, which engage one another to maintain female fitting 1002 and male fitting 1004 in contact with one another and prevent axial movement of female fitting 1002 relative to male fitting 1004. Straight tooth 1030 includes a radially-extending engagement interface, as detailed in FIG. 10C.

[0160] Female fitting 1002 and male fitting 1004 each include a corresponding biased tooth 1030 extending circumferentially about each of female fitting 1002 and male fitting 1004, which engage one another to maintain female fitting 1002 and male fitting 1004 in contact with one another and prevent axial movement of female fitting 1002 relative to male fitting 1004. Biased tooth 1039 includes an engagement interface that is biased relative to the radial direction, as detailed in FIG. 10D. Biased tooth 1039 has an engagement interface biased such that applying a force to pull female fitting 1002 axially apart from male fitting 1004 causes female fitting 1002 to move radially toward male fitting 1004, and vice versa.

[0161] Female fitting 1002 includes a pocket 1032 extending circumferentially about the interior of female fitting 1002 configured to accept a distal end 1034 of male fitting 1004. Distalend 1034 is sized and shaped to fit into pocket 1032. An edge of female fitting 1002 forming pocket 1032 may overlap a portion of distal end 1034.

[0162] Male fitting 1004 includes a pocket 1038 extending circumferentially about the exterior of male fitting 1004 configured to accept a distal end 1036 of female fitting 1002. Distal end 1036 is sized and shaped to fit into pocket 1038. An edge of male fitting 1004 forming pocket 1038 may overlap a portion of distal end 1036.

[0163] Engagement of distal ends 1034 and 1036 with pockets 1032 and 1038 prevents distal ends 1034 and 1036 from moving radially such that female fitting 1002 and male fitting 1004 move radially away from one another. The result is increased strength of pipe assembly 1000 under a radial load and / or bending load.

[0164] The various dimensions illustrated in FIGS. 10B-10D are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0165] FIGS. 11A-11D illustrate a pipe assembly 1100, including female fitting 1102 and male fitting 1104.

[0166] Female fitting 1102 and male fitting 1104 each include a corresponding straight tooth 1130 extending circumferentially about each of female fitting 1102 and male fitting 1104, which engage one another to maintain female fitting 1102 and male fitting 1104 in contact with one another and prevent axial movement of female fitting 1102 relative to male fitting 1104. Straight tooth 1130 includes a radially-extending engagement interface, as detailed in FIG. 11C.

[0167] Female fitting 1102 and male fitting 1104 each include a corresponding biased tooth 1130 extending circumferentially about each of female fitting 1102 and male fitting 1104, which engage one another to maintain female fitting 1102 and male fitting 1104 in contact with one another and prevent axial movement of female fitting 1102 relative to male fitting 1104. Biased tooth 1139 includes an engagement interface that is biased relative to the radial direction, as detailed in FIG. 11D. Biased tooth 1139 has an engagement interface biased such that applying a force to pull female fitting 1102 axially apart from male fitting 1104 causes female fitting 1102 to move radially toward male fitting 1104, and vice versa.

[0168] Female fitting 1102 includes a pocket 1132 extending circumferentially about the interior of female fitting 1102 configured to accept a distal end 1134 of male fitting 1104. Distalend 1134 is sized and shaped to fit into pocket 1132. An edge of female fitting 1102 forming pocket 1132 may overlap a portion of distal end 1134.

[0169] Male fitting 1104 includes a pocket 1138 extending circumferentially about the exterior of male fitting 1104 configured to accept a distal end 1136 of female fitting 1102. Distal end 1136 is sized and shaped to fit into pocket 1138. An edge of male fitting 1104 forming pocket 1138 may overlap a portion of distal end 1136.

[0170] Engagement of distal ends 1134 and 1136 with pockets 1132 and 1138 prevents distal ends 1134 and 1136 from moving radially such that female fitting 1102 and male fitting 1104 move radially away from one another. The result is increased strength of pipe assembly 1100 under a radial load and / or bending load.

[0171] The various dimensions illustrated in FIGS. 11B-11D are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0172] FIGS. 12A-12B illustrate a pipe assembly 1200, including female fitting 1202 and male fitting 1204.

[0173] Female fitting 1202 includes a circumferential groove 1240. Male fitting 1204 includes a circumferential land 1242 sized and shaped to engage groove 1240. Engagement of land 1242 with groove 1240 prevents female fitting 1202 from moving axially away from male fitting 1204.

[0174] Female fitting 1202 includes a pocket 1232 extending circumferentially about the interior of female fitting 1202 configured to accept a distal end 1234 of male fitting 1204. Distal end 1234 is sized and shaped to fit into pocket 1232. An edge of female fitting 1202 forming pocket 1232 may overlap a portion of distal end 1234.

[0175] Male fitting 1204 includes a pocket 1238 extending circumferentially about the exterior of male fitting 1204 configured to accept a distal end 1236 of female fitting 1202. Distal end 1236 is sized and shaped to fit into pocket 1238. An edge of male fitting 1204 forming pocket 1238 may overlap a portion of distal end 1236.

[0176] Engagement of distal ends 1234 and 1236 with pockets 1232 and 1238 prevents distal ends 1234 and 1236 from moving radially such that female fitting 1202 and male fitting1204 move radially away from one another. The result is increased strength of pipe assembly 1200 under a radial load and / or bending load.

[0177] The various dimensions illustrated in FIG. 12B are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0178] FIG. 13 illustrates a perspective view of a pipe assembly 1300, including a female fitting 1302 and a male fitting 1304.

[0179] Male fitting 1304 may include a circumferentially extending reduced distal portion 1350 machined radially inwardly from the outer surface of male fitting 1304. Distal portion 1350 may include at least one L-shaped slot 1354 machined radially inwardly from the outer surface of distal portion 1350. Distal portion 1350 may include a plurality of L-shaped slots 1354 machined radially inwardly from the outer surface of distal portion 1350, and circumferentially spaced about distal portion 1350.

[0180] Female fitting 1302 may include a circumferentially extending reduced distal portion 1352 machined radially outwardly from the inner surface of female fitting 1302. Distal portion 1352 may include at least one peg 1356 extending radially inwardly from the inner surface of distal portion 1352. Distal portion 1352 may include a plurality of pegs 1356 extending radially inwardly from the inner surface of distal portion 1352, and circumferentially spaced about distal portion 1352.

[0181] At least one peg 1356 is sized and shaped to fit within L-shaped slot 1354. Where a plurality of pegs 1356 and a plurality of L-shaped slots 1354 are included, the circumferential spacing of each are matched such that pegs 1356 are able to fit within L-shaped slots 1354.

[0182] During assembly of pipe assembly 1300, pegs 1356 are circumferentially aligned with the distal ends of L-shaped slots 1354. Female fitting 1302 and male fitting 1304 are radially aligned and moved axially toward one another until pegs 1356 engage L-shaped slots 1354 and extend completely down an axial leg of L-shaped slots 1354. At this point, female fitting 1302 and male fitting 1304 are rotated relative to one another (about the axial axis) to cause pegs 1356 to extend down a circumferential leg of L-shaped slots 1354. In this arrangement, female fitting 1302 and male fitting 1304 are prevented from moving axially away from one another.

[0183] When one wishes to remove female fitting 1302 from male fitting 1304, one rotates female fitting 1302 relative to male fitting 1304 (about the axial axis) in the opposite direction from engagement, such that pegs 1356 are in the axial leg of L-shaped slots 1354, at which point female fitting 1302 and male fitting 1304 can be moved away from one another axially.

[0184] FIGS. 14A-14H illustrate a pipe assembly 1400, including a female fitting 1402 and a male fitting 1404.

[0185] Female fitting 1402 and male fitting 1404 each include a corresponding straight tooth 1430 extending circumferentially about each of female fitting 1402 and male fitting 1404, which engage one another to maintain female fitting 1402 and male fitting 1404 in contact with one another and prevent axial movement of female fitting 1402 relative to male fitting 1404. Straight tooth 1430 includes a radially-extending engagement interface, as detailed in FIG. 14B.

[0186] FIG. 14B illustrates a partial sectional view of pipe assembly 1400, including a standard tooth in a female fitting and a male fitting.

[0187] Male fitting 1404 includes an elongated ramp portion 1434. Elongated ramp portion 1434 my extend half the length, or more, of the overall mating surface of male fitting 1404 with female fitting 1402, measured in the axial direction. Elongated ramp portion 1434 may be angled relative to the axial direction, for example at an angle of about 2.9 degrees.

[0188] Female fitting 1402 includes an elongated ramp portion 1432. Elongated ramp portion 1432 my extend half the length, or more, of the overall mating surface of female fitting 1402 with male fitting 1404, measured in the axial direction. Elongated ramp portion 1432 may be angled relative to the axial direction, for example at an angle of about 2.9 degrees.

[0189] The various dimensions illustrated in FIGS. 14A-14H are exemplary in nature, but it is understood that these dimensions may be scaled up or down while maintaining the same ratios to one another as illustrated here. That is, the relation between the dimensions of each of the female and male fittings, as well as the various features (e.g., standard teeth, biased tooth, and the like), may be the same during scaling up or down of the pipe assembly.

[0190] To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use.See Bryan A. Garner, A Dictionary of Modem Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” To the extent that the term “substantially” is used in the specification or the claims, it is intended to take into consideration the degree of precision available or prudent in manufacturing. To the extent that the term “selectively” is used in the specification or the claims, it is intended to refer to a condition of a component wherein a user of the apparatus may activate or deactivate the feature or function of the component as is necessary or desired in use of the apparatus. To the extent that the term “operatively connected” is used in the specification or the claims, it is intended to mean that the identified components are connected in a way to perform a designated function. As used in the specification and the claims, the singular forms “a,” “an,” and “the” include the plural. Finally, where the term “about” is used in conjunction with a number, it is intended to include ± 10% of the number. In other words, “about 10” may mean from 9 to 11.

[0191] As stated above, while the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art, having the benefit of the present application. Therefore, the application, in its broader aspects, is not limited to the specific details, illustrative examples shown, or any apparatus referred to. Departures may be made from such details, examples, and apparatuses without departing from the spirit or scope of the general inventive concept.

Claims

CLAIMS1. A pipe assembly, comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; and at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by the angle Al.

2. The pipe assembly of claim 1, wherein the angle Al is 22 degrees.

3. The pipe assembly of claim 1, wherein the angle Al is between 20 degrees and 24 degrees.

4. The pipe assembly of claim 1, wherein the angle Al is between 18 degrees and 26 degrees.

5. The pipe assembly of claim 1, wherein the male fitting biased tooth biased engagement surface is biased in a proximal direction of the male fitting.

6. The pipe assembly of claim 1, wherein the female fitting biased tooth biased engagement surface is biased in a proximal direction of the female fitting.

7. The pipe assembly of claim 1, wherein the male fitting includes two standard teeth and one biased tooth, and wherein the female fitting includes two standard teeth and one biased tooth.

8. A pipe assembly, comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; and at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by the angle Al, wherein the angle Al is between 18 degrees and 26 degrees.

9. The pipe assembly of claim 8, wherein the angle Al is 22 degrees.

10. The pipe assembly of claim 8, wherein the angle Al is between 20 degrees and 24 degrees.

11. The pipe assembly of claim 8, wherein the male fitting biased tooth biased engagement surface is biased in a proximal direction of the male fitting.

12. The pipe assembly of claim 8, wherein the female fitting biased tooth biased engagement surface is biased in a proximal direction of the female fitting.

13. The pipe assembly of claim 8, wherein the male fitting includes two standard teeth and one biased tooth, and wherein the female fitting includes two standard teeth and one biased tooth.

14. A pipe assembly, comprising: a male fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; at least one biased tooth extending circumferentially about the radially outer side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al, wherein the male fitting biased tooth biased engagement surface is biased in a proximal direction of the male fitting; and a female fitting, comprising: an annular portion of pipe having a radially inner side and a radially outer side; at least one standard tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one standard tooth includes a radial engagement surface parallel to a radial direction of the annular portion of pipe; and at least one biased tooth extending circumferentially about the radially inner side of the annular portion, wherein the at least one biased tooth includes a biased engagement surface biased relative to the radial direction of the annular portion of pipe by an angle Al,wherein the female fitting biased tooth biased engagement surface is biased in a proximal direction of the female fitting.

15. The pipe assembly of claim 14, wherein the angle Al is 22 degrees.

16. The pipe assembly of claim 14, wherein the angle Al is between 20 and 24 degrees.

17. The pipe assembly of claim 14, wherein the angle Al is between 18 and 26 degrees.

18. The pipe assembly of claim 14, wherein the male fitting includes two standard teeth and one biased tooth, and wherein the female fitting includes two standard teeth and one biased tooth.

Images