Patent Application
20150125117
Typical systems for coupling optical fiber to a tubular for purposes of sensing parameters such as strain, temperature, pressure, acoustic energy of the tubular include adhesively bonding the optical fiber to the tubular. Positioning the adhesive, typically an epoxy, into continuous contact between the optical fiber and the tubular has proven difficult. Some systems rely on pumping an epoxy into the tubular after the optical fiber has been placed therewithin. Pumping epoxy has limitation of length through which the epoxy can be effectively pumped. The industry is therefore always receptive to new arrangements and methods to overcome the foregoing and other limitations with conventional systems.
Disclosed herein is a method of coupling optical fiber to a tubular. The method includes positioning at least one optical fiber at least partially within an annular cavity defined between a tubular and an elongated member and radially compressing the elongated member against the tubular.
Further disclosed herein is a fiber optic mounting arrangement. The arrangement includes a tubular, an elongated member positioned within the tubular, at least one optical fiber at least partially positioned between the tubular and the elongated member and the at least one optical fiber is parameter transmissively mounted to the tubular.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Referring to
The radial compression can be in response to radial expansion of the elongated member 18, for example. Radial expansion of the elongated member 18 in this embodiment is in response to pressure applied to an inside 30 of the elongated member 18 that causes the walls 34 of the elongated member 18 to be “blown” radially outwardly. Heating of the elongated member 18 can facilitate the radial expansion thereof by partially melting and thereby softening the walls 34. This softening can also aid in adhering the elongated member 18 to one or both of the tubular 14 and the optical fibers 22. In so doing, an adhesive 38 specifically for adhering the elongated member 18 to one or both of the tubular 14 and the optical fibers 22 is optional.
While this embodiment is directed to radially expanding the elongated member 18 with pressure applied therewithin, other embodiments are contemplated. For example, the tubular 14 could be a form of heat shrinkable tubing such that heat alone causes the tubular 14 to shrink radially. Alternately, the elongated member 18 can be configured to radially expand in response to being heated to essentially work inversely to that of heat-shrink tubing.
Heating of the elongated member 18 can be accomplished indirectly by heating of the tubular 14 that in turn heats the elongated member 18 or by more direct means, including heating the elongated member 18 prior to it being positioned within the tubular 14 or heating the elongated member 18 after positioning it within the tubular by heated fluid that is pumped therethrough, for example. The elongated member 18 can also be heated by electrical induction through the tubular 14.
Optionally, adhesion of the elongated member 18 to the optical fibers 22 can be facilitated by cladding the optical fibers 22 with the same or similar material that forms at least an outer surface 42 of the elongated member 18. In so doing, cladding 46 of the optical fibers 22 can essentially be welded to at least the surface 42 of the elongated member 18. Similarly, at least the inner surface 26 of the tubular 14 can be made of or coated with an optional material 50 of the same or similar material that forms the outer surface 42 of the elongated member 18 to allow welding to take place between the outer surface 42 and the material 50. Additionally, the optical fibers 22 can be adhered directly to the inner surface 26 as well, including through welding of the cladding 46 to the material 50. This adhesion, without the use of additional materials beyond those of the optical fiber 22, the tubular 14 and the elongated members 18 themselves, can improve energy transmissibility between the tubular 14 and the optical fiber 22 and improve thermal response time over system that employ separate adhesive materials.
Making the elongated member 18, the cladding 46 and the material 50, if used, out of a polymer may make the process of boding them together easier since lower temperatures can typically be employed to soften them in comparison to use of a material such as metal were employed instead. Metal, however, may be desirable for use as the tubular 14 for other reasons other than facilitating bonding, and is fully compatible with embodiments disclosed herein.
Referring to
Referring to
Referring to
Each of the embodiments illustrated employ three of the optical fibers 22, although more or fewer of the optical fibers 22 can be employed in other embodiments. Using a plurality of the optical fibers 22 allows the arrangements 10, 110, 210 and 310 disclosed to provide differential strain information experienced between one side of the elongated member 18 and another side. Embodiments that employ fewer of the optical fibers 22, including possibly just a single one of the optical fibers 22 can provide similar sensing as to those with multiple fibers by twisting the optical fibers 22 in a helical fashion around the elongated member 18, 118, 218 and 318, for example. Such a configuration could be created by wrapping the optical fiber(s) 22 around the elongated member or by twisting the elongated member 18 after the optical fiber(s) 22 are positioned relative to the outer surface 42, such as within the grooves 54, 154, for example.
Additionally, the elongated members 18, 118, 218, 318 can be solid or can be hollow (as shown in the embodiments illustrated). Hollow embodiments, allow for transporting fluid or pressure therethrough as well as running conduits 328 such as electrical conductors, other optical fibers or hollow tubes, therethrough.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
