Patent Application
20160145971
The field of the invention is subterranean tools that have a movable member that needs to maintain a rotational orientation and a device to realign the member using engagement with an indexing device.
In choke valves the sliding sleeve has a port and is axially moved for more or less alignment with a surrounding housing port to control the pressure drop across the choke valve. Typically a hydraulic fluid metering device or a j-slot assembly is used to move the sliding sleeve axially in the surrounding housing to control the opening size. In some designs in the past the sliding sleeve and the housing are rotationally locked with a lug in an axial recess arrangement. However, when made in certain small sizes there may not be enough room to use such a rotational locking arrangement. Other alignment systems use an open slot in a j-slot that steps the sliding sleeve axially for opening and closing the valve. That design is illustrated in U.S. Pat. No. 7,367,393 in the form of alignment lug 64 aligning housing components for a choke valve. Alignment is important because the openings in the sliding sleeve and the housing need to be in the same plane as the sliding sleeve is axially moved to control the pressure drop across the choke when it is partially or fully open. There are times when the choke is between the full closed and full open positions and other procedures are conducted through the valve that can result in relative rotation between the sliding sleeve and the housing in the absence of a rotational lock.
Accordingly, the present invention addresses a situation where the configuration of the choke such as the requirements for a pressure rating on the housing or a drift dimension through the sliding sleeve dictate against the provision of the known solution of rotationally locking the sliding sleeve to the surrounding housing. Instead of the traditional rotational alignment solutions that are not practically available in some situations, the present invention provides an alignment ring having a repeating pattern profile to match a similar profile at an end of the sliding sleeve. Accordingly, regardless of the initial orientation of the matching patterns, advancing the patterns toward each other will always produce an axial alignment of the circumferentially spaced ports on the sleeve with circumferentially spaced openings in the surrounding housing for normal operations. The sliding sleeve is preferably directed to the closed choke position which is the position where the profiles engage. If there is initial misalignment then bringing the patterns together realigns the sliding sleeve and housing ports for subsequent normal operation. This is done without reduction of the sliding sleeve drift dimension. These and other aspect of the present invention will be more readily apparent from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.
An alignment device for a sliding sleeve in a housing in a tubular string features a patterned alignment ring that remains stationary. The sliding sleeve in one of its end positions has a mating profile such that profile misalignment results in profile alignment as the sliding sleeve is axially advanced toward the alignment ring. In a choke application the fully closed position of the choke brings the profiles together to induce relative rotation into an aligned configuration of the ports on the sliding sleeve with the ports on the surrounding housing. Misalignment can occur when tools are run through the sliding sleeve for other downhole operations and the design parameters for the choke prevent the use of alignment lugs in axial slots. The mating profiles do not reduce the drift dimension through the sliding sleeve and allow higher housing pressure ratings for deep set applications with large operating differential pressures.
In the
Alignment ring 30 is preferably wedged to inner wall 32 to keep it in position and for rotationally locking it. A keyway and key arrangement could be an alternative option or pin in a slot that has a bend and spring loading to hold the ring 30 rotationally locked to the housing 10 could also be used. Ring 30 has alternating peaks 32 and valleys 34 with the valleys 34 defined by a short axial slot to relieve stress at the transition of a pair of sloping surfaces 38 and 40. Surfaces 38 and 40 continuously alternate for 360 degrees such that on engagement of surfaces 42 and 44 with the stationary surfaces 38 and 40 the sliding sleeve 16 will either already be in alignment with the openings 12 in the housing 16 or as in the case of comparing
It is preferred that the dimensions of the meshing patterns at the lower end of the sleeve 16 and on the top of the alignment ring 30 have identical dimensions. Some variation in the peak angles 46 and 48 can be tolerated so that the angles are not the same with angles 46 preferably being smaller, but other variations are contemplated as long as enough rotation is induced to get the desired axial alignment between openings 18 and 20 on one hand and openings 12 on the other hand. Other meshing shapes are contemplated to get the desired rotation for opening alignment for full capacity operation of the choke valve. Applications to other tools are contemplated such as isolation sliding sleeve valves or other devices that operate on the principle of port alignment and axial misalignment with a peripheral seal in between.
Those skilled in the art will appreciate that the alignment method described above does not reduce the drift dimension of sleeve 16 and requires no removal of material from housing 10 for grooves to accept lugs or wall reductions into which a lug is inserted to potentially reduce the pressure rating of the housing. This can be a significant factor in deep applications or those with high operating differential pressures.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
