Patent Application
20080061101
Referring to the figure an embodiment of a filamentous member injector 10 is illustrated. Injector 10 includes a housing 12 comprising a base 14 and a cover 16. The base and cover are pressure sealably connectable to one another to create a pressure vessel so that pressure within the housing can be set above or equal to that of the tubular in which the filamentous member (genus) is to be deployed. The filamentous member may be of any type and for convenience is hereinafter referred to as “fiber” (species) without intending to limit the application of the invention. In the illustration, the cover is retained to the base by a plurality of threaded fasteners such as bolts but it is to be understood that alternative arrangements such as threading the cover directly to the base or utilizing latches or the like is equally applicable. The housing 12 includes a fluid inlet 18, a fiber inlet 20 and a fluid/fiber outlet 22. Fluid outlet 22 is connectable to a short length tubular 24 through which a fiber 26 is to be urged for deployment to a target tubular (not shown). The short length tubular 24 is of narrow inside dimension (restricted diameter) so that fluid flowing therein flows more quickly thereby generating a greater fluid drag on fiber 26. This is helpful at a start of a run to aid in getting the fiber introduced far enough into the system that the fluid drag force is greater than the blowback force. In order to use a short length of the tubular 24 however, instead of a much longer length, which longer length would be necessary to actually balance the fluid drag force with the blowback force, an additional insertion force is required. A method and apparatus to apply such insertion force is taught in this disclosure.
As disclosed herein a mechanical force is applied to the fiber to achieve the desired total force on the fiber to prevent blow back from occurring. Within the housing 12 is a capstan 28. Capstan 28 is driven by a drive 30, which in one embodiment may be a belt drive as illustrated. A belt 32 may be driven by any applicable drive system such as a motor. As in the case with all capstan devices, the drive is rotary causing the capstan to spin on its axis. In addition to the capstan 28, a spiral guide 34 is provided, to operably communicate with the fiber 26 relative to the capstan 28 and which is affixed to the housing 12 in such a way that the spiral guide 34 does not spin with the capstan but remains in close proximity to a surface of the capstan 28. The guide 34 itself has for its purpose to reduce the possibility of the fiber 26 becoming entangled due to the plurality of wraps the fiber makes around the capstan 28 in addition to causing the fiber to engage the capstan at one axial end and to leave the capstan and another axial end as shown. By providing a spiral (or helical) pathway such as a grove, or such as structures defining a groove, the fiber 26 may be guided as noted. The guide 34 is best appreciated with reference to
It should be noted that fluid inlet 18 can be utilized for any fluid medium whether it be liquid or gas, for example, water or air. The pressurization of housing 12 allows for equalization across outlet 22 with the higher-pressure environment of a tubular through which the fiber is to be deployed. As was noted above, the pressure in tubular 24 beyond outlet 22 is significant. In one application, pressure is at 5700 psi. This much pressure makes introduction of fiber 26 difficult as the pressure itself acts upon the cross sectional area of the fiber to push it back out of tubular 24, thus the need for mechanical injection. A corollary however is that a compressive force on an optic fiber, for example, along an axis thereof, is not well tolerated by the fiber. Damage to the fiber is relatively certain with relatively small compressive axial loads thereon. In accordance with this disclosure however, such compressive load is avoided while injection force is maintained.
The Capstan drive will impart a drive force to the fiber 26 only if there is a physical tension on the fiber 26 from the downstream end of the housing 12 from, for example tubular 24. Such a force causes the fiber to bind against the capstan 28 thereby enabling the capstan to drive the fiber. If there is no tensile force on fiber 26, the capstan will merely spin within the coil of fiber created by the several passes of the fiber around the capstan 28. As such the insertion force on the fiber presented by the capstan is very gentle. If by chance the fiber is impeded in its forward motion, even by only a small amount, the necessary tensile force on the fiber will diminish and the capstan will naturally cease driving the fiber. Thereby the fiber is not damaged by any condition where deployment is hindered. In one embodiment, it is the fluid drag force on the fiber alone that provides sufficient tensile force thereon to activate the capstan drive.
In one embodiment of the device disclosed herein, the capstan 28 is removable from the housing 12 to facilitate easy manual wrapping of fiber 26 therearound. The fiber once wrapped around the capstan 28 is fed completely through short tubular 24. The capstan is then deposited within housing 12 in such a way as to engage the drive. This can be by way a gear mesh or any other convenient connection. Once the capstan is properly wound with fiber and returned to housing base 14, the cover 16 is pressure-sealingly secured to base 14 thereby creating pressure sealed housing 12. A target tubular is connected to short tubular 24 by any conventional means and the motor drive is activated to spin the capstan. As noted above, without a tensile force on the fiber 26, the fiber is not bound to the capstan and no mechanical drive force is coupled to the fiber. Rather, the capstan spins harmlessly within the spiral wrap of the fiber until fluid is supplied under pressure to fluid inlet 20. Application of fluid pressure to fluid inlet 20 causes a flow to begin through the fluid and fiber outlet 22. As flow is increased, fluid drag on the segment of the fiber 26 within short tubular 24 begins to pull on the fiber. When the fluid drag builds to a sufficient level to create a tensile force on the fiber, the fiber becomes bound to the capstan thereby allowing the capstan to impart a mechanical injection force to the fiber. Injection of the fiber will continue until a desired depth is reached, flow is stopped or reduced below the bind threshold, the fiber is mechanically impeded in some way or any other force stops or slows injection at which time the fiber will cease providing the requisite tensile force on the capstan to bind itself thereto and the capstan will harmlessly spin within the fiber spiral wrapped around the capstan.
While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
This application claims priority to provisional application 60/844,021 filed Sep. 12, 2006, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60844021 | Sep 2006 | US |
