Patent Application
20110227337
The present disclosure relates to fittings for making mechanically attached connections between a conduit and another fluid component, for containing liquid or gas fluids. More particularly, the disclosure relates to fittings for jacketed conduits.
In accordance with an embodiment of one or more of the inventions presented in this disclosure, a fitting for a jacketed conduit includes a first fitting component (for example, a fitting body or fitting nut), a second fitting component (for example, a fitting body or fitting nut), at least one conduit gripping device, and a jacket sealing device for providing a moisture-tight seal against the jacketed conduit. In one embodiment, the protective cover or sheath of the jacketed conduit is removed or otherwise absent from a portion of the tubing so that the conduit gripping device can grip and seal against the metal tubing. The jacket sealing device forms a moisture-tight seal against a portion of the protective cover or sheath, and may additionally foim a moisture-tight seal against a sealing surface of one of the first and second fitting components. In a more specific embodiment, the fitting assembly may include a first fitting component, a second fitting component joinable to the first fitting component, one or more conduit gripping devices, a sealing element and a seal engaging member that is joinable with at least one of the metal conduit, the first fitting component, and the second fitting component to compress the sealing element against a jacketed portion of the metal conduit. The sealing element may form a moisture-tight seal with the jacketed portion of the metal conduit. The sealing element may additionally form a moisture-tight seal against a sealing surface of the fitting (for example, against an extension of the fitting nut).
In one such exemplary embodiment, the seal engaging member includes a fastening member, such as a seal nut, that is threadably assembled with the fitting (for example, with a threaded extension of a fitting nut) for compression of the sealing element between a drive surface of the seal nut and a sealing surface of the fitting (for example, a sealing surface of the fitting nut). Additional features may include a sleeve that extends from the fastening member to cover the hex flats of the fitting nut, a sealing element adapted to provide a positive indication of proper tightening of the fastening member, and a sealing element formed to be retained with a fastening member as a self-contained subassembly.
In another embodiment, a fitting is provided with a jacket sealing device that includes an O-ring sealing element that is compressed between an end portion of the fitting (for example, the fitting nut) and a seal engaging member to seal against a jacket end portion of a jacketed tubing when the seal engaging member is assembled with the fitting.
In another embodiment, a fitting is provided with a jacket sealing device that includes a seal engaging member that is slid or pushed against an end face of the fitting (for example, on a fitting nut) to compress a sealing element against the fitting and into sealing engagement with a jacketed portion of a jacketed conduit.
In another embodiment, a fitting is provided with a jacket sealing device that includes a sleeve-type sealing element secured over a jacket end portion at a first end of the sleeve and over a portion of the fitting (for example, over a portion of a fitting nut) at a second end of the sleeve. In one such embodiment, a clamp-type seal engaging member is secured around the sleeve to compress or constrict the sleeve to maintain sealing engagement with the jacket end portion and fitting nut. In another embodiment, a sealing sleeve is sized to provide a sealing compression grip on the jacket end portion and on the fitting nut without utilizing a seal engaging member.
Other exemplary jacket sealing arrangements that may not require a separate seal engaging member include an elastomeric cover that slides on the conduit into sealing engagement with an end face of a fitting nut, a grommet that is wedged or pushed against an inner peripheral recess of a fitting nut, an O-ring seal that is squeezed between a jacket end portion of a conduit and a fitting nut end face, an O-ring that is compressed within an internal recess of a fitting nut to seal against a jacket end portion, and a sealant that is injected through an access port in a fitting nut into an internal recess of the fitting nut to seal against a jacket end portion.
According to another aspect of one or more of the inventions, a fitting is provided with a jacket sealing device that provides a seal between a jacket end portion and a fitting nut without a separate sealing element. In one such embodiment, the jacket end portion is deformed or otherwise manipulated to function as a sealing element. For example, a jacket end portion may be rolled or expanded and axially compressed between a fitting nut and a seal engaging member assembled with the fitting nut. As another example, a portion of a fitting nut may be inserted underneath a jacket end portion, and the jacket end portion may be radially compressed between the fitting nut and a seal engaging member assembled with the fitting nut.
In another embodiment, a fitting nut is provided with a jacket sealing structure configured to grip and seal against a jacketed portion of a conduit when the fitting is installed on the conduit. In one example, a seal engaging member is assembled with a fitting nut to radially compress a jacket sealing structure of the fitting nut into sealing engagement with the jacket end portion. In another example, a fitting nut is provided with a radially inwardly biased jacket sealing structure that is configured to seal against a jacket end portion upon installation of the fitting with the tubing, without the assembly of a separate seal engaging member.
In accordance with another embodiment of one or more of the inventions presented in this disclosure, a fitting for jacketed tubing includes a body-nut sealing arrangement to provide a moisture-tight seal over a threaded connection between a fitting body and a fitting nut. In one such embodiment, a sealant is applied to the mating threads of the fitting body and fitting nut. In another embodiment, a seal is provided between opposed surfaces of the fitting body and fitting nut, with the seal being compressed between the opposed surfaces to effect a seal around the mating threads when the fitting is pulled up. In still another embodiment, a jacket sealing device is configured to fully surround the assembled fitting connection of the fitting body, fitting nut, and conduit end to provide a moisture-tight seal over both the body-nut connection and the unjacketed tubing outboard of the mechanical seal between the fitting and the conduit end.
The drawings illustrate various embodiments of fitting assemblies, wherein:
Although the exemplary embodiments herein are presented in the context of a stainless steel tube fitting, the inventions herein are not limited to such applications, and will find use with many different conduits such as tube and pipe as well as different materials other than 316 stainless steel, for example, copper, including different metals for either the conduit, the gripping devices or the fitting components or any combination thereof. The inventions may also be used for liquid or gas fluid systems. While the inventions herein are illustrated with respect to particular designs of the jacket sealing devices, conduit gripping devices and fitting components, the inventions are not limited to use with such designs, and will find application in many different fitting designs that use one or more conduit gripping devices. In the drawings, various gaps and spaces between parts (for example, gaps between the ferrules and the conduit in a finger-tight position) may be somewhat exaggerated for clarity or due to scale of the drawings. Although we describe the exemplary embodiments in terms of “jacketed tubing,” the inventions are not limited to tubing but may be used with any conduit including pipe. Therefore the word “tubing” herein is used only as an example of one type of conduit with which the inventions may be utilized. The inventions also are not limited to conduits that may fall within the common understanding of the terms “jacket” and “jacketed,” rather the terms jacket and jacketed are used for convenience to refer to any protective sheath, cover, treatment or coating, and to any metal conduit having a protective sheath, cover, treatment or coating about its exterior surface, especially protective layer or layers for anticorrosion protection.
While various inventive aspects, concepts and features of the inventions may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present inventions. Still further, while various alternative embodiments as to the various aspects, concepts and features of the inventions—such as alternative materials, structures, configurations, methods, devices and components, alternatives as to form, fit and function, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the present inventions even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure, however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or fowling part of an invention, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts and features that are fully described herein without being expressly identified as such or as part of a specific invention, the inventions instead being set forth in the appended claims. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated.
With reference to the drawings, several embodiments of the inventions are presented. All references herein to “radial” and “axial” are referenced to the X axis, as shown in the drawings, except as may otherwise be noted. Also, all references herein to angles are referenced to the X axis except as may otherwise be noted.
External corrosion of metal tubing can negatively impact the performance of tubing installations. Although corrosion resistant tubing may be used, such tubing is usually of higher cost which can be a significant factor for systems that use long and extensive tubing runs. As a lower cost alternative to corrosion resistant tubing, a protective polymer or elastomer layer, commonly known as a jacket, is applied over standard, less expensive tubing. The jacket may be formed onto the tubing such as by extrusion or receive the tubing such as with a slip fit, shrink-fit, spray-on, dip-coat, etc., to name a few examples. The protective jacket, which is also referred to herein as a protective layer, coating, cover or sheath, may be made of any suitable material, with polyvinylchloride (PVC) and thermoplastic urethane (TPU) being in common use today, but other materials may be used including but not limited to PFA and PTFE. The jacket is used to provide a water proof or moisture proof barrier to inhibit corrosion, for example crevice corrosion, that might otherwise occur due to environmental exposure, particularly marine environments, for example. Jacketed tubing may be used with mechanical connections such as ferrule type tube fittings, but in order to make the mechanical connection, the jacket must be cut away, pulled back, or otherwise absent from the tube end or other portion where the mechanical connection is to be made in order for the ferrules (or other such conduit gripping devices) to properly grip and seal the tubing. In the past, the exposure of the end portion of the tubing for fitting make-up further necessitated adding a heat shrink material or an adhesive material such as silicon tape to the exposed tube end after the mechanical connection was completed. The use of shrink wrap material or self adhesive tape have numerous disadvantages, particularly for post-installation activities. The present disclosure is directed to better designs and methods for protecting the exposed tubing where the protective jacket has been removed, for example, to allow a mechanical connection to be made to the tubing without compromising the corrosion resistance of the jacketed tubing.
The present disclosure contemplates fitting assemblies that provide both a mechanical connection to an unjacketed or exposed portion of a metal tube end, and a moisture-tight seal against a protective covering or jacket of the tubing to seal the unjacketed portion of the tubing from external moisture and other contaminants. According to an aspect of the present disclosure, a fitting assembly may include a tube fitting component and a jacket sealing device that seals against an outer surface of the jacket when the jacket sealing device is assembled with the tube fitting component. In one embodiment, a jacket sealing device is configured to be assembled with a fitting nut to provide a moisture-tight seal between the fitting nut, the jacket sealing device, and the tubing jacket.
While the inventive aspects of the present disclosure may be utilized with a variety of fittings, in one embodiment, a two-ferrule compression tube fitting is provided with a jacket sealing device for preventing exposure to moisture of an uncovered or unjacketed portion of a tube (which may, but need not, be the endmost portion of the tube) with which the fitting is assembled. In the exemplary embodiment of the drawing, a fitting assembly 10 is provided for jacketed tubing J. The jacketed tubing J includes a metal tube 1 and a protective coating or sheath 2, also commonly referred to as a jacket. The jacket 2 may be made of any suitable material including but not limited to PVC and TPU, and may be applied to the metal tube 1 by any suitable process as is well known in the art. Jacketed tubing is commercially available from different tubing suppliers. The metal tube may be provided in any metal that is convenient for a particular installation, including but not limited to stainless steel and copper.
The fitting assembly 10 may include a first coupling or fitting component 3 having a first end or end connection 4 that is joinable to a second coupling or fitting component 5. These parts are commonly known in the art as a nut and body respectively, wherein the body 5 receives a tube end portion, and the nut end connection 4 may be joined to the body 5 during make up of the fitting. Although we use the common terms of body and nut herein as a convenience, those skilled in the art will appreciate that the inventions are not limited to applications wherein such terminology may be used to describe the parts. The body 5 may be a stand-alone component as illustrated or may be integral with or integrated or assembled into another component or assembly such as, for example, a valve, a tank or other flow device or fluid containment device. The body 5 may have many different configurations, for example, a union, a tee, an elbow and so on to name a few that are well known in the art. Although the body 5 and the nut end connection 4 are illustrated as being threadably joined together by a threaded connection T, threaded connections are not required in all uses. For example, some fittings have parts that are clamped together to give one example. Fittings are also commonly referred to in the art as male fittings or female fittings, with the distinction being that for a male fitting the body includes an externally male threaded portion and the nut includes an internally female threaded portion. For a female fitting, the nut includes an externally male threaded portion and the body includes an internally female threaded portion. The exemplary embodiments herein illustrate a male fitting assembly embodiment, for example, but the inventions may be conveniently adapted for use with a female fitting assembly.
The mechanical body-nut connection 40 of the fitting 10 may be used to form a fluid-tight connection between an end portion 12 of the tubing 1 and the body 5 using one or more conduit gripping devices 6, which in the exemplary embodiments herein may be realized in the form of one or more ferrules 6, including in this embodiment a front ferrule 61 and a back ferrule 62. However, conduit gripping devices other than those that may be understood in the art as ‘ferrules’ may also be used with the inventions herein. The tubing 1 typically bottoms against a radial shoulder 13 that is part of the body 5, and is well known. The body 5 includes a camming surface 20 that engages the front portion of the front conduit gripping device or ferrule 61. The front ferrule 61 includes a camming surface 26 at its back or outboard end that engages a front portion of a second or back conduit gripping device or ferrule 62. The back ferrule 62 includes a driven surface 32 that engages a drive surface 34 of the female nut 4. The front and back ferrules include cylindrical interior walls 37, 39 that are closely received over the outer surface 38 of the tubing 1 and within a cavity 7 formed by the nut 4 and body 5. Although the exemplary embodiments herein illustrate fitting assemblies that use a conduit gripping device or ferrule set having two conduit gripping devices or ferrules, the inventions will readily find application to fittings that may use only a single conduit gripping device, as well as fittings that may use ferrule sets having more than two conduit gripping devices, or additional parts other than just ferrules or conduit gripping devices, for example, additional seals.
The body 5, end connection portion 4 of the nut 3 and the ferrules 6 thus form a mechanical connection 40 that is well known and commonly used for as a flareless tube end connection to provide a grip and seal against the outer metal surface of the tubing 1. In order for the mechanical connection 40 to work properly, the protective jacket 2 is removed or otherwise absent from a portion of the tubing 1 that will be used to form the mechanical connection. Thus, the jacket 2 will extend to an end 42, leaving an exposed portion 38 of the tubing 1. The jacket 2 may be assembled or fitted with the tubing 1 so as to terminate at the end 42. Alternatively, an endmost portion of the jacket 2 initially covering the exposed portion 38 may be removed by any convenient technique including cutting or peeling/rolling back the jacket 2.
It is important to note that the exemplary geometric shapes, configurations and designs of the fitting coupling components 4, 5 and the conduit gripping devices 61, 62 are a matter of design choice and will depend in great measure on the materials used, and the design and performance criteria expected of the fitting. Many different coupling components and conduit gripping device designs are known in the art and may be designed in the future, including, for example, flared tubing connections and permanent fitting connections (e.g., Phasetite®).
The term “complete pull-up” and derivative terms as used herein refers to joining the fitting components 4 and 5 together so as to cause the one or more conduit gripping devices 6 to deform, usually but not necessarily plastically deform, to create a fluid-tight seal and grip of the mechanical connection 40 on the tubing 1. A “partial pull-up” and derivative terms as used herein refers to a partial but sufficient tightening of the male and female fitting components together so as to cause the conduit gripping device or devices to deform so as to be radially compressed against and thus attached to the tubing, but not necessarily having created a fluid-tight connection or the required grip that is achieved after a complete pull-up. The term “partial pull-up” thus may also be understood to include what is often referred to in the art as pre-swaging wherein a swaging tool is used to deform the ferrules onto the tubing sufficiently so that the ferrules and the nut are retained on the tubing prior to being mated with the second fitting component to form a fitting assembly. A finger tight position or condition refers to the fitting components and conduit gripping devices being loosely assembled onto the tubing but without any significant tightening of the male and female fitting components together, usually typified by the conduit gripping device or devices not undergoing plastic deformation. The drawings herein show the mechanical connection 40 in a finger-tight condition prior to final tightening and pull-up.
In order to effect complete grip and seal, the nut end connection 4 and body 5 are tightened together—commonly known in the art as pull-up or pulling up the fitting and derivative terms—such that the back ferrule 62 and front ferrule 61 axially advance against their respective camming surfaces 26 and 20. This causes a radially inward compression of the ferrules against the outer metal surface of the tubing 1 to effect grip and seal. In the exemplary fitting assembly herein, grip is primarily achieved with the back ferrule, with the front ferrule primarily providing a fluid-tight seal. However, in some designs the front ferrule may also grip the tubing and the back ferrule may also provide a fluid-tight seal. Thus, the term “conduit gripping device” may include two distinct functions, namely grip and seal, whether or not a specific conduit gripping device performs one or both of those functions. The present inventions may alternatively be used with single conduit gripping device style fittings in which a single conduit gripping device performs both the grip and seal functions, and still further alternatively may be used with fittings that use more than two conduit gripping and sealing devices. Although not limiting the scope of the present inventions, the exemplary fitting design illustrated herein is of a type well known and commercially available from Swagelok Company, Solon, Ohio. Examples of such fittings that may be provided with one or more of the inventive features of the present disclosure are described in a number of issued and pending patent applications, including U.S. Pat. Nos. 5,882,050 and 6,629,708, which describe a two-ferrule fitting with a rear ferrule having a geometry designed to reduce galling, localized loading, and torque forces, the entire disclosures of which are fully incorporated herein by reference.
To provide a moisture-tight seal over the exposed portion 38 of the tubing 1, the fitting 10 of
In an exemplary method, a mechanical connection for jacketed tubing is provided, with the method including the steps of attaching a fitting to an unjacketed portion of a metal tube by using a ferrule-type fitting assembly to provide grip and seal against the unjacketed portion of the tube, and securing a sealing member in sealing engagement with the fitting (for example, with the nut) and with a jacketed portion of the tube by joining a seal engaging member with at least one of the fitting nut, fitting body, and metal tube.
The fitting assembly 10a thus may utilize known or later developed mechanical connections of the flareless tube end variety using one or more conduit gripping devices or ferrules, with a nut that is modified to include a second end that can be mated to a second nut (or seal nut) or cap. While the seal nut 73a may be tightened before the mechanical connection is pulled-up, in some applications, it may be desirable to pull up the mechanical connection before tightening the seal nut, to minimize twisting of the tubing jacket 2a on the tube 1a by the seal nut 73a during pull up.
When disassembling the exemplary fitting 10a, it may be desirable to loosen the seal engaging member or seal nut 73a before loosening the fitting nut 3a, such that the jacket end portion 44a is not twisted on the tubing 1a as the fitting nut 3a is loosened. To impede loosening of the fitting nut 3a while the seal nut 73a remains tightened, the seal nut 73a may be provided with a sleeve or extension, shown schematically at 74a, which covers the hex flats of the fitting nut 3a when the seal nut 73a is tightened. This sleeve 74a may be integral to the seal nut 73a or assembled with the nut (e.g., a plastic sheath). In one embodiment, the sleeve 74a may be removable and/or disposable, such that the sleeve may be removed to make intentional adjustments to the fitting nut 3a and/or the seal nut 73a (for example, allowing an installer to apply one wrench to the fitting nut flats and a second wrench to the seal nut flats to tighten or loosen the seal nut 73a. The sleeve 74a may be provided with text or other indicia notifying the installer that the seal nut 73a should be loosened before loosening the fitting nut 3a.
The sealing element may be provided in many different suitable geometries and materials. In one embodiment, a fitting nut extension and seal nut may utilize the designs and dimensions of one or more electrical cable gland assemblies known in the art, in combination with a cable gland grommet or a seal member resembling a cable gland grommet utilized as a sealing element between a jacket end portion and the fitting nut. In the embodiment of
While thread engagement between the seal nut 73a and the fitting nut 3a may be sufficient to maintain a sufficiently tight, jacket sealing condition for the jacket sealing device 70a, in other embodiments, a seal nut may be secured in the jacket sealing condition by one or more nut-locking features, including, for example, a counter nut, lock washer, sealant, or other such configuration, for example, to prevent loosening of the seal nut due to system vibrations, thermal cycling, or other such conditions.
In another embodiment, a grommet seal may be configured to provide a positive indication of proper installation of the seal engaging member (e.g., proper tightening of a seal nut). In the exemplary embodiment of
In still another embodiment, a grommet sealing element may be formed to be retained with a seal engaging member as a self-contained subassembly, to ensure the sealing member is present and properly oriented during fitting assembly. In the exemplary embodiment of
In other embodiments, an O-ring seal may be compressed between a fitting nut and a seal engaging member (e.g., a second nut or seal nut) to seal against the fitting nut and the jacket end portion.
Other types of seal engaging members may be utilized to compress one or more sealing elements with the tubing jacket and with a sealing surface of the fitting nut. For example,
In still another embodiment, as shown in
In another embodiment, a push-to-connect seal engaging member may be utilized to seal against an end portion of a tubing jacket and an end face of a fitting nut.
In yet another embodiment, a sealing sleeve may be secured (e.g., by a clamp or other seal engaging member) over a jacket end portion and a portion of the fitting nut to provide a moisture-tight seal over an exposed end of a jacketed tubing.
In other embodiments, a sealing element may be sized and configured to provide a sufficient interference fit or gripping engagement with a jacket end portion and fitting nut to effect an adequate seal without use of a separate seal engaging member (for example, the seal engaging member may be integral with the sealing element). For example, as shown in
In another embodiment, as shown in
In still another embodiment, as shown in
Other types of sealing elements may be provided to seal directly with a fitting nut. For example, as shown in
In other embodiments, a fitting nut may be providing with a sealing element retaining recess, with a retained sealing element providing a moisture-tight seal between the fitting nut and the tubing jacket. For example, as shown in
In additional embodiments of the present disclosure, the fitting nut and/or seal engaging member may be configured to seal directly with the tubing jacket. For example, an end portion of the jacket may be deformed or otherwise manipulated to function as a sealing element. In one such embodiment, an endmost portion of the jacket may be rolled up and axially compressed between the fitting nut and seal engaging member to effect a seal.
In another embodiment, an endmost portion of the jacket may be expanded and radially compressed between the fitting nut and seal engaging member to effect a seal. In the exemplary embodiment of
In another embodiment, as shown in
In yet another embodiment, as shown in
In other embodiments, a fitting nut may be provided with a jacket sealing structure configured to grip and seal against the tubing jacket when the fitting is installed on the tubing. In one such embodiment, a seal engaging member is assembled with the fitting nut to radially compress the jacket sealing structure of the fitting nut into sealing engagement with the tubing jacket. For example, as shown in
In another embodiment, a fitting nut is provided with a radially inwardly biased collar that is configured to seal against the tubing jacket upon installation of the fitting with the tubing, without the assembly of a separate seal engaging member. In the exemplary embodiment of
According to another aspect of the present disclosure, a fitting may be further configured to provide a fluid-tight or moisture-tight seal between the body and nut threads of the fitting assembly, thus further protecting an unjacketed portion of a tube end from external moisture or other contaminants. In one embodiment, a thread sealant may be provided between the fitting body and nut threads to effect a moisture-tight seal. Any suitable thread sealant may be utilized, including, for example, PTFE-free sealants, such as Swagelok PTFE-Free sealant.
In another embodiment, a seal may be provided between opposed surfaces of a fitting body and fitting nut, such that when the nut is pulled up on the body, the seal is compressed between the opposed surfaces to effect a seal around the fitting threads. In the exemplary embodiment of
In still another embodiment, a jacket sealing device may be configured to fully surround the assembled fitting connection of a fitting body, fitting nut, and tube end, thereby providing a moisture-tight seal over both the body-nut connection and the space between the nut and the end of the tubing jacket. In the exemplary embodiment of
The inventive aspects have been described with reference to the exemplary embodiments. Modification and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
The present application claims priority from U.S. Provisional Application Ser. No. 61/315,202, entitled “FITTING FOR JACKETED TUBING,” filed on Mar. 18, 2010, the entire disclosure of which is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61315202 | Mar 2010 | US |
