Background and Summary

Fluid fittings, such as hydraulic or pneumatic fittings, are used throughout various types of systems for conveying flowing fluids. The fluid fittings form sealed connections with pipe or tube sections, adapt and couple pipe or tube sections with different sizes or shapes, and may further aid in directing, regulating or measuring fluid flow. When installed, fluid fittings are designed to form a tight seal with adjacent system elements so as to contain the fluids in the system and maintain system pressure. However, over their lifetime, fluid fittings can be subject to a wide range of operating conditions and environments that can cause degradation. For example, in hydraulic systems, fluid fittings may be subject to vibration, which over time can fatigue the fittings and can cause cracking and eventual failure. In other applications, fittings can be exposed to highly corrosive or abrasive fluids, high and low temperature extremes, and cycling fluid pressures, which can also induce and accelerate fitting degradation.

When a fluid fitting fails, the entire system, and related components and/or assembly lines, may be shut down to enable repair and/or to reduce downstream damage caused by the fitting failure. In some situations, the system downtime can be significant. For example, fluid fittings that fail while installed in a system may be difficult to remove. This is especially true when the fitting degradation or failure damages fitting threads, or results in a threaded portion of the fitting remaining installed, with no part of the fitting available to manipulate. Such failure modes can make fitting removal difficult and time-consuming. Such difficulties can be exacerbated by the fitting's location in the system, which can often be difficult to reach with appropriate tools for removal.

Further still, not only is removal of a failed fitting difficult, but the removal process itself can result in still more problems. For example, failed fittings can often be removed only by drilling out the remaining component that is threaded-in-place. Such operation can result in shavings or fragments of a failed fitting being introduced into the fluid system, potentially causing damage to still other system components. As another example, blowtorches may be used to remove failed fittings, again creating the potential for inadvertent damage. And in some cases, failed fittings can be removed only by cutting out sections of the system and replacing those entire sections, substantially increasing downtime and increasing maintenance costs.

The inventor herein has recognized these issues and provides various approaches to at least partially address them. In one example, a fluid fitting is provided that includes an interior wrenching portion that facilitates rotation and removal of the fitting after failure. The fitting may also include a shear groove that induces failure of the fitting at the location of the shear groove to better ensure that the wrenching portion is accessible after the failure occurs. In this way, when the fitting fails (at the shear groove, in one example) the threaded-in-place piece that is left still screwed-in can be removed by, for example, applying a wrenching tool that matingly fits into the wrenching portion. The failed component is thus easily removed, while reducing formation of any shavings and/or other debris that would otherwise potentially contaminate the fluid.

It will be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Brief Description of the Drawings

FIG. 1 is an example illustrating a perspective view of a fluid fitting.

FIG. 2 is an example illustrating a side view of the fluid fitting of FIG. 1. FIG. 3 is an example illustrating an end view of an interior wrenching portion of a threaded portion of the fluid fitting of FIG. 1.

FIG. 4 shows examples of various types of fluid fittings including some of the features described in the fitting of FIG. 1.

FIG. 5 is an example illustrating a failed fluid fitting. The Figures are drawn approximately to scale.

Detailed Description

The following detailed description relates to several example embodiments of a fluid fitting. A first example embodiment of a fluid fitting for use in a fluid conveying system is shown in FIGS. 1-3. The first example embodiment of the fluid fitting comprises a first end with a threaded exterior, a second end opposite the first threaded end, and a central interior passageway that has openings at both the first and the second end of the fluid fitting. The fluid fitting also includes at least one exterior wrenching portion, as well as an interior wrenching portion that extends inward into the interior passageway from the first end with the threaded exterior. FIG. 1 is a perspective view, FIG. 2 is a side view, and FIG. 3 is an end view of the first example embodiment. The interior wrenching portion and its relation to the first end with the threaded exterior surface and the interior passageway is illustrated in the view of FIG. 1. A further embodiment of the fluid fitting includes a shear groove on an exterior surface of the fitting. The shear groove is also shown in the side view of FIG. 2. Several additional example embodiments of fluid fittings are shown in FIG. 4, including side, perspective and end views of those example embodiments. FIG. 5 illustrates another example embodiment, in which a manual wrenching tool can be used to extract a part of the fluid fitting that is threaded-in-place after failure at the shear groove. Note that as explained herein, fluids may include various types, including hydraulic, pneumatic, air, gas, and combinations and mixtures thereof, for example.

Referring now to Figure 1, it illustrates an example of a perspective view of a first example embodiment of a fluid fitting 100. As a non-limiting example, fluid fitting 100 includes a first end 110 with a threaded exterior, and a second end 120 opposite the first end. As an example, the fluid fitting 100 can be formed from steel, brass, bronze, plastic or aluminum, or combinations thereof; alternative materials can also be used.

The first end with the threaded exterior 110 may be a male threaded portion that may be externally threaded with a thread form that is straight and which is designed to mate with a corresponding female thread. Alternatively, the first end with the threaded exterior 110 may include a thread form that is tapered and designed to engage and mate, forming a seal with a corresponding female thread for coupling the fluid fitting to an additional fluid conveying system element such as a fluid fitting or a pipe section. One or more exterior wrenching portions 122 may be present to allow for rotation of the first end with the threaded exterior relative to the second end, or to allow for rotation of the entire fluid fitting as a unitary piece. The exterior wrenching portions 122 may have a hexagonal shaped external cross-section, which permits the fluid fitting to be rotated and installed with tooling, such as socket wrenches or open or box-ended wrenches. The fitting further includes a shear groove 130.

Continuing with FIG. 1, fluid fitting 100 also comprises an interior passageway 140 for conveying fluid into and out of the fluid fitting. The interior passageway 140 may pass fully through the fluid fitting between first and second openings 142 and 144 that open flush with the first and second ends of the fitting, although the cross-section of the interior passageway may vary along the length of the fitting as described herein. An interior wrenching portion 150 extends from the first end 110 of the fluid fitting inward into the interior passageway 140 for a defined length, such as at least up to and past the shear groove 130. A cross-sectional geometry of the interior wrenching portion is configured to receive a manual wrenching tool with a corresponding geometry that matingly fits into the interior wrenching portion upon insertion of the manual wrenching tool. Thus, the fluid fitting can be rotated by inserting the manual wrenching tool into the interior wrenching portion and applying torque to the manual wrenching tool. For example, if the fitting fails at the shear groove while installed, the tool may be inserted into the interior wrenching portion from the left as viewed in FIG. 1, so that the remaining threaded-in-place portion can be removed from its installed position. This illustrates why the interior wrenching portion of the internal passageway extends from an edge of the opening 144 at the far right hand side end (as viewed in FIG. 1) inward all the way up to and at least somewhat past the shear groove. From that point, the interior cross section of the interior passageway may continue to the left end (as viewed in FIG. 1) with a circular shape, or another shape, or optionally with the same shape as the interior wrenching portion, if desired.

As explained previously, fluid fittings installed in fluid conveying systems can be exposed to harsh operating environments that can include vibrations, cycling pressures, abrasive or corrosive fluids, and temperature extremes. Consequently, installed fluid fittings can fail in-place, resulting in a loss of integrity of the fluid conveying system, which may require the system to be shut down, in order to extract and replace the failed, damaged fittings. Extraction of a damaged fitting can be very laborious and costly, especially when the damage results in an impacted fitting fragment that remains threaded-in-place. For example, prior conventional methods of extracting impacted fittings commonly involve using power tools to drill out the fitting. The drilling out method may be hazardous to maintenance workers and prone to damaging elements in the fluid conveying system adjacent to the impacted fitting fragment because the power tools are difficult to control; the drill can inadvertently damage the threaded surfaces of the damaged fitting or adjacent elements, thereby rendering extraction of the fitting even more difficult or near impossible, and the entire piping section containing the piping section may need to be removed and replaced. Furthermore, drilling out damaged fittings can often introduce contaminants such as metal shavings into the fluid system arising from the drilled out impacted fitting or from adjacent elements that are damaged by the drill out. Another known method of removing damaged fittings involves heating up the damaged region with a blowtorch, which is also a hazardous process that can cause inadvertent damage to the system. As discussed above, in still other instances, the only way to remove a damaged fitting is to remove and replace the entire piping section containing the damaged fitting fragment. Consequently, extracting damaged or impacted fitting fragments, and repairing any auxiliary damage arising from the fitting fragment extraction process, can often be labor-intensive, time consuming and can incur high costs, especially when the fluid conveying system must be shut down until the work is completed.

Accordingly, if a fluid fitting, according to the first example embodiment, installed in a fluid conveying system fails, and results in a damaged or impacted fluid fitting fragment that remains threaded-in-place, a manual wrench tool with the correct geometry can simply be used to extract the fitting.

Continuing with FIG. 1, as noted above, the interior wrenching portion 150 may extend inward into the interior passageway 140 of the fluid fitting, defining at least an interior wall 160 of the interior passageway 140, for a length of at least the length of the threaded exterior of the first end 110 and up to the shear groove 130. In this manner, a manual wrenching tool can be used to extract an impacted fluid fitting fragment after failure of the fluid fitting occurring at any location along the fluid fitting's threaded exterior surface, or even at a location slightly beyond the threaded exterior surface (e.g. between the wrenching portion 122 adjacent to the threaded exterior surface of the fluid fitting), and up to the shear groove 130.

As shown in FIG. 2, the fluid fitting may further comprise one or more other portions, including for example, a tapered portion 124 and straight portions 126 and 128. The example embodiment can further comprise a shear groove 130. As an example, the straight portion 128 immediately adjacent to the threaded exterior of the first end 110 may include the shear groove 130 machined into its outer surface, and the shear groove can be located immediately adjacent to the threaded exterior surface of the first end 110. The shear groove may be separate from the threads, where the groove is not continuous with any of the threads, and in one example the shear groove is radially deeper than any of the threads as shown in FIG. 2. The shear groove may also be wider than the thread pitch in one example. As noted, the interior wrenching portion 150 extends into the interior passageway, defining at least the interior wall 160 of the interior passageway 140, for a length at least to the shear groove. The purpose of the shear groove is to act as a stress riser in the fluid fitting, thereby directing a failure of the fluid fitting to occur at the location of the shear groove before other locations of the fitting fail.

Prior fluid fitting designs have strived to reduce the risk of mechanical failure, improve the durability of the fluid fitting by employing high strength materials, and eliminate stress risers during manufacture of the fluid fitting. One common method of eliminating stress risers is to employ welding processes using fillets during fabrication of fluid fittings. These methods add high costs to the manufacture of the fluid fittings, and may be used in the present fitting, if desired. However, the eventual failure of fluid fittings manufactured using prior methods may occur at any location on the fitting, including at or within the threaded portions of the fluid fitting, resulting in a damaged fitting or fitting fragment that can be impacted, threaded-in-place, and difficult to access. Consequently any cost benefits from improved durability of the fluid fitting due to employing high strength materials or welding fillets, can quickly be negated by labor-intensive, time consuming procedures for extracting damaged or impacted fitting fragments. The approach taken by the example embodiments herein, which incorporate a shear groove stress riser into the design of a fluid fitting, is thus counterintuitive. Yet, such a counterintuitive approach achieves significant unexpected advantages as explained already.

Specifically, incorporating the shear groove stress riser into the design of the fluid fitting directs failure of the fluid fitting to occur at the location of the shear groove. And because of the interior wrenching portion, which extends at least along the interior passageway to the shear groove, will be accessible when the fitting fails at the shear groove, removal of any remaining pieces of the fitting is thus significantly improved, while reducing the introduction of debris and contaminants into the system. In one example configuration, the interior wrenching portion 150 extends inward into the interior passageway 140 from the first end 110 of the fluid fitting, defining at least an interior wall 160 of the interior passageway, for a length at least to the position of the shear groove. In this manner, the interior wrenching portion 150 of a fluid fitting fragment that remains threaded-in-place after the failure of a fluid fitting that has cleaved at the shear groove 130 will be accessible to a manual wrenching tool. As such, a manual wrench with the correct geometry can simply be used to extract the fluid fitting fragment following failure of the fitting at the shear groove 130. In this manner, a failed fluid fitting can be replaced expeditiously, inexpensively, and safely as compared to a fluid fitting without an interior wrenching portion and/or without a shear groove, thereby drastically reducing costs associated with labor, time, and equipment and process down time. Furthermore, the risk of contaminating the fluid system with foreign materials, incurring the need for additional preventive maintenance is averted since the failure occurs relatively cleanly and completely at the shear groove (as compared to a fluid fitting failing without a shear groove) and drilling or cutting of metal with power tools can be averted. Damaged fittings located in confined or restricted spaces, such as underneath process equipment, can also be more easily removed and replaced because tools which are smaller and simpler than power tools and blow torches (e.g. manual wrenches) can be employed.

Figure 3 illustrates an end view of the first example embodiment of fluid fitting 100 taken within the first end 110. In the example embodiment illustrated in Figure 3, the cross-sectional geometry and the interior wall 160 of the interior wrenching portion 150 is grooved. The end view thus shows an interior dimension, dl, of the interior wrenching portion, an outer dimension, d2, of the interior wrenching portion 150 (equivalent to the interior diameter of the threaded portion or the diameter of the interior passageway 140), an outer dimension, d3, of the threaded portion, a thread depth, d4, and a dimension, d5, of the exterior wrenching portion. Thus a wall thickness, tl , of the threaded portion is equivalent to d3 - d2, and a wall thickness, t2, of the interior wrenching portion is equivalent to d2 - dl .

In certain example embodiments, where the cross-sectional geometry of the interior wrenching portion is not grooved, dl and d2 may be equivalent, and the wall thickness, t2, of the interior wrenching portion can be 0 (e.g. hex, triangle). In other example embodiments, dl and d2 may not be equivalent, or in some example embodiments, where the cross-sectional geometry of the interior wrenching portion is not radially symmetrical, dl and d2 may not be applicable. In some cases, t2 and the dl and d2 can vary in accordance with type and size of the appropriate wrench. The interior wrenching portion 150 shown in the example embodiment of FIGS. 1-3 has a Torx Spline® cross-sectional geometry. Further example embodiments can include interior wrenching portions with square, hex, slot, cruciform, triple square, bowtie, butterfly, claw, double hex, pentalobe, polydrive, spanner, spline, triangle, and triangular slotted cross-sectional geometries or other geometries of wrenching or drive tools.

Figure 4 illustrates further examples of different types of fluid fittings incorporating the various features of the fitting described in FIGS. 1-3. Figure 4 illustrates side, perspective, and end views of a straight union 410, a 90° elbow 420, and a 135° elbow 430. Straight union 410, and elbows 420 and 430 all employ, as examples, interior wrenching portions with Torx Spline® cross-sectional geometries. Other non-limiting example types of fluid fittings that can employ combinations of the example embodiments described herein include unions, tees, caps, plugs, wyes, reducers, crosses, nipples, couplings, adapters, valves, filters, flow meters, and other types of fittings or fluid conveying system elements that may be coupled together. As such, one of ordinary skill in the art can understand that further example embodiments of fluid fittings can comprise a plurality of ends with threaded exteriors, a plurality of interior wrenching portions, and a plurality of shear grooves.

Figure 5 illustrates an example of a fluid conveying system 500, after failure of an installed fluid fitting, having a shear groove 130 and interior wrenching portion 150. As a result of the fluid fitting failure, a fluid fitting fragment 510 is left behind, threaded into a fluid conveying system element 520, to which the original fluid fitting had been coupled before the failure. The fluid fitting fails at the stress riser created by the fluid fitting shear groove 130. As such the fluid fitting fragment 510 that may remain threaded-in-place includes the first end 110 with a threaded exterior and a part of the straight portion 128 immediately adjacent to the first end 110 of the original fluid fitting, previously containing shear groove 130 before failure of the fluid fitting. The first end 110 of the fluid fitting fragment 510, includes the interior wrenching portion 150, having, for example, a Torx Spline® cross-sectional geometry (not shown), which is thus accessible from the sheared-off end. Thus, a tool 530 with a geometry corresponding to the cross-sectional geometry of the interior wrenching portion 150, for example a Torx Spline® wrench, can be inserted into the interior wrenching portion 150 of the fluid fitting fragment 510, and rotated (by applying torque to the wrench) to remove the fluid fitting fragment 510 from the fluid conveying system element 520, without the use of power tools.

Numerous advantages are associated with the example embodiments, including but not limited to: eliminating or reducing the use of special power tools for drilling out fluid fitting fragments; improving worker safety and reducing risk of injury because power tools are avoided; reducing the risk of damaging fluid system elements from power tools or damaged threads; reducing contamination of the fluid system by foreign materials and further associated maintenance required to correct damage to the system by foreign materials or to remove the foreign materials; reducing the potential of additional cost from premature obsolescent; reducing labor costs; reducing costs associated with process downtime; and facilitating removal of damaged fittings from confined or restricted spaces (e.g. under process equipment).

The example embodiments described above apply to various common types of pipe fluid fittings employing threaded portions for coupling the fluid fitting to other elements of the fluid conveying system, including those fittings sealing using tapered threads, o-ring or compression seals, flanges, flared ends, quick-disconnects or quick couplers, those with multiple openings, and those employing face, beam, swaged, or compression seals. Furthermore, the example embodiments may apply to many types of fluid fittings, known to one of ordinary skill in the art, such as unions, tees, elbows, wyes, and other fluid fitting types that may have a plurality of threaded portions, a plurality of shear grooves, a plurality of interior wrenching portions, and a plurality of other portions.

Note that the example embodiments described above can be used for fluid fittings used in various fluid system configurations, and may be used in one or more of any number of strategies for fluid fitting repair. As such, various embodiments illustrated may be combined in the sequence illustrated, in alternate sequences, or in some cases omitted. Likewise, the sequence or combination of the embodiments is not necessarily called for to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated embodiments may also be repeatedly combined depending on the particular strategy being used. It will be appreciated that the configurations disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above embodiments can be applied to unions, tees, elbows, wyes, and other fluid fitting types. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various configurations, and other features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims are to be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.