The present invention relates generally to tube and pipe fittings, and more particularly to a locking sleeve apparatus for securing the tube and pipe fitting connections.
Tube fittings provide an extremely convenient way to connect tube sections in the field with little tube preparation. By turning a nut, “ferrules” are deformed such that they plastically deform into the OD of the tubing, thereby creating a metal-to-metal seal, as well as force a cone into the body of the fitting, thereby creating the seal against the fitting. One such tube fitting is a tube fitting system offered by the Swagelok Company. Due to the plastic deformation on the tube OD, these fittings are quite resilient in terms of creating a leak-tight, high pressure seal with very little tubing cleaning, polishing, and preparation in general. However, if compression on the fitting is reduced, the contact stress on the back and front ferrule will also decrease and a leak can result. This is particularly a problem in tube fitting applications in environments where there is vibration, thermal cycling, or both. Threaded connections can come loose, and in the case of bolted connections, repeated transverse displacement of the joint relative to the bolts have been shown to cause nuts to loosen and back off.
Thus, what is needed is a solution to secure tube fittings, particularly in environments subject to vibration.
The present invention relates to a locking sleeve apparatus which is configured to secure tube fittings or other threaded connections subject to loosening, particularly in environments subject to vibration, thermal cycling, or both.
In an aspect, the locking sleeve apparatus comprises a sleeve adapted to engage oppositely rotating connection components, such that the connection components impart opposing rotational forces on the locking sleeve apparatus. The locking sleeve apparatus is secured in position over the oppositely rotating connection components by a locking mechanism positioned internally therein.
In an embodiment, the locking sleeve apparatus is an elongate tube having an inner profile configured to slidingly engage the oppositely rotating connection components.
In another embodiment, the inner profile of the locking sleeve apparatus may be hexagonal to match commonly available rotating connection components.
In another embodiment, the oppositely rotating connection components are threaded hexagonal nuts which rotate in opposite directions relative to each other to secure a tube or pipe fitting. Alternatively, the pipe fittings themselves may have hexagonal outer profiles on them which may be tightened relative to each other.
In another embodiment, the locking mechanism is a resiliently flexible locking clip sized and shaped to engage a channel or slot formed into an inner surface of the locking sleeve apparatus.
In another embodiment, the channel or slot formed into the inner surface of the locking sleeve apparatus is positioned near at least one end of the elongate tube of the locking sleeve apparatus, and allows the locking mechanism to be accessible from at least one end of the locking sleeve apparatus.
In another embodiment, the locking sleeve apparatus may include a fixed shoulder or flange at one end with a smaller diameter than the inner surface of the locking sleeve apparatus over most of its length.
In another embodiment, in situations where the oppositely rotating connection components have a different profile, an adapter may be fitted over the smaller connection component to provide a common outer profile for engaging the locking sleeve apparatus.
In another embodiment, corresponding adapters may be fitted over both oppositely rotating connection components to adapt the components to the profile of a locking sleeve apparatus, such that the connection components are prevented from rotating within the locking sleeve apparatus.
In another embodiment, the locking sleeve is sized to provide a press-fit over the connection components.
In another embodiment, the locking sleeve is malleable and mechanically deformable at each end to enable clamping of the locking sleeve in position.
In another embodiment, the locking sleeve apparatus comprises one or more apertures formed through the locking sleeve.
In another embodiment, the one or more apertures are threaded to receive a set-screw to lock the locking sleeve in position.
In another embodiment, the one or more apertures are positioned to receive an adhesive which may be injected internally within the locking sleeve.
In another embodiment, the locking sleeve apparatus further comprises a shrink-tube which when positioned over the locking sleeve and shrunk encapsulates the locking sleeve in position.
In another embodiment, the one or both ends of the locking sleeve are threaded, either internally or externally, to receive a correspondingly threaded nut.
In another embodiment, the locking sleeve is adapted to expand upon heating to be slid over top of the fittings, and adapted to shrink upon cooling over the fittings to keep the locking sleeve in position.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its applications to the details of construction and to the arrangements of the components set forth in the following description or the examples provided therein, or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As noted above, the present invention relates generally to tube and pipe fittings, and more particularly to a locking sleeve apparatus for securing the tube and pipe fitting connections.
In an aspect, the locking sleeve apparatus comprises a sleeve adapted to engage oppositely rotating connection components, such that the connection components impart opposing rotational forces on the locking sleeve apparatus. The locking sleeve apparatus is secured in position over the oppositely rotating connection components by a locking mechanism positioned internally therein.
In an embodiment, the locking sleeve apparatus is an elongate tube having an inner profile configured to slidingly engage the oppositely rotating connection components.
In another embodiment, the inner profile of the locking sleeve apparatus may be hexagonal to match commonly available rotating connection components.
In another embodiment, the oppositely rotating connection components are threaded hexagonal nuts which rotate in opposite directions relative to each other to secure a tube or pipe fitting.
In another embodiment, the locking mechanism is a resiliently flexible locking clip sized and shaped to engage a channel or slot formed into an inner surface of the locking sleeve apparatus.
In another embodiment, the channel or slot formed into the inner surface of the locking sleeve apparatus is positioned near at least one end of the elongate tube of the locking sleeve apparatus, and allows the locking mechanism to be accessible from at least one end of the locking sleeve apparatus.
In another embodiment, the locking sleeve apparatus may include a fixed shoulder or flange at one end with a smaller diameter than the inner surface of the locking sleeve apparatus over most of its length.
In another embodiment, in situations where the oppositely rotating connection components have a different profile, an adapter may be fitted over the smaller connection component to provide a common outer profile for engaging the locking sleeve apparatus.
In another embodiment, corresponding adapters may be fitted over both oppositely rotating connection components to adapt the components to the profile of a locking sleeve apparatus, such that the connection components are prevented from rotating within the locking sleeve apparatus.
Although
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By way of example, in the oil industry, usage of these tube fittings commonly comprise connecting long lengths of ¼ inch tubing to a “turn around” sub—a pressure-tested device that is essentially a U-turn at the end of two parallel ¼ inch capillary lines:
However, a common problem with tube fittings 200 is that they can come loose, particularly in environments where there is vibration. In downhole applications, the mechanism that causes loosening of the nuts 200A, 200B is not as clear. However, the likely culprits are vibration and thermal cycling (displacements caused by repeated thermal expansion and contraction) during a downhole procedure. In any case, loosening of a joint's contact stress can allow a leak, which may have negative and often expensive consequences. The cost to retrieve failed downhole components is high, when considering service rig time and lost well production, let alone the replacement cost of the failed instrumentation or components as a result of the leak.
In order to address this problem, the inventor has developed a locking sleeve apparatus, as will now be described below.
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Thus, in an illustrative embodiment, the locking sleeve apparatus 300 is a one-piece cylinder with a hex profile bored through it. As shown in
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Once this is done, the locking sleeve apparatus 300 may be used to slide over the cap 500 and nut 510 of the compression style connector, and any necessary adapter 520, as shown in
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While an illustrative example of one possible locking method has been shown and described, the inventors have also contemplated alternative embodiments for retaining the locking sleeve in position.
As shown in
In another embodiment, as shown in
In another embodiment, set-screws 920 may be configured and positioned to land on a flat of each fitting nut. This would allow sleeve to have a circular inner diameter, making it much easier to manufacture. The sleeve cylinder would still couple the two fitting nuts (via the set screws) and prevent either from backing off.
Multiple pins or set-screws 920 could be used in an angular configuration on a single plane, or in multiple places along the length of the fitting lock, so as to target the recesses in the fitting, and to aid in locking the sleeve 300 in place.
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A variation of this embodiment could be a shrink-tube placed over the fitting lock and the tubing. Once shrunk down, everything including the locking sleeve is encapsulated, and friction between the shrink-tube and the locking sleeve would prevent movement of the locking sleeve within the shrink-tube.
In yet another embodiment, one or both ends of the locking sleeve may be threaded, either internally or externally, to allow a nut to be attached to the end of the locking sleeve. The nut would be cut radially to allow it to slide over top of the tube, and then attach to the end of the fitting lock, thereby preventing it from translating off of the fitting, and thereby losing fitting nut engagement.
In another embodiment, one or more holes may be drilled radially in through the outer diameter of the locking sleeve, and a glue and/or epoxy of some sort can be injected into the fitting lock, and forced to fill the void spaces in between the tube fitting and fitting lock. The mechanical bond between the glue, fitting lock, and tube fitting would hold it in place. Any means of bonding the fitting to the fitting lock may be used.
In still another embodiment, a slight interference fit would allow the fitting lock to be pre-heated and slid over top of the fitting. Upon cooling, the contraction of the fitting lock would result in compressive forces between the fitting lock and the tube fitting. Friction between the mating surfaces would prevent translation of the fitting lock.
In a similar manner, an interference fit can be created by wedging a material axially, in between the flats of the fitting nuts and the fitting lock. This would be done from either side of the fitting lock to engage both nuts.
Thus, in an aspect, there is provided a locking sleeve apparatus for securing rotating connection components, comprising: an elongate tube having an inner profile configured to slidingly engage an outer profile of a plurality of rotating connection components; and one or more locking mechanisms positioned internally in the elongate tube near at least one end of the elongate tube; whereby, the plurality of rotating components are mechanically coupled by the elongate tube, and prevented from rotating relative to each other.
In an embodiment, the inner profile of the elongate tube matches commonly available rotating connection components with multi-sided outer profiles.
In another embodiment, the rotating connection components are configured to rotate in opposite directions relative to each other to tighten or loosen.
In another embodiment, the elongate tube includes a channel or slot formed into an inner surface to receive the locking mechanism therein.
In another embodiment, the locking mechanism is a resiliently flexible locking clip sized and shaped to engage the channel or slot within the locking sleeve.
In another embodiment, the locking mechanism is accessible from at least one end of the locking sleeve apparatus.
In another embodiment, the locking sleeve apparatus includes a fixed shoulder or flange at one end.
In another embodiment, the locking sleeve apparatus further comprises an adapter for fitting over smaller rotating connection components to provide a common outer profile for engaging the locking sleeve apparatus.
In another embodiment, the locking sleeve is sized to provide a press-fit over the connection components.
In another embodiment, the locking sleeve is malleable and mechanically deformable at each end to enable clamping of the locking sleeve in position.
In another embodiment, the locking sleeve apparatus further comprises one or more apertures formed through the locking sleeve.
In another embodiment, the one or more apertures are threaded to receive a set-screw to lock the locking sleeve in position.
In another embodiment, the one or more apertures are positioned to receive an adhesive which may be injected internally within the locking sleeve.
In another embodiment, the locking sleeve apparatus further comprises a shrink-tube which when positioned over the locking sleeve and shrunk encapsulates the locking sleeve in position.
In another embodiment, one or both ends of the locking sleeve are threaded, either internally or externally, to receive a correspondingly threaded nut.
In another embodiment, the locking sleeve is adapted to expand upon heating to be slid over top of the fittings, and adapted to shrink upon cooling over the fittings to keep the locking sleeve in position.
While illustrative embodiments have been described above, various changes and modifications may be made without departing from the scope of the invention, which is defined by the following claims.
Number | Date | Country | |
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62594806 | Dec 2017 | US |