Patent Application
20050077039
1. Field of the Invention
Embodiments of the present invention generally relate to a gripping apparatus for supporting tubulars. Particularly, the aspects of the present invention relate to slip type gripping assembly disposable within a rotary table.
2. Description of the Related Art
The handling of pipe strings has traditionally been performed with the aid of a spider. Typically, spiders include a plurality of slips circumferentially surrounding the exterior of the pipe string. The slips are housed in what is commonly referred to as a “bowl”. The bowl is regarded to be the surfaces on the inner bore of the spider. The inner sides of the slips usually carry teeth formed on hard metal dies for engaging the pipe string. The exterior surface of the slips and the interior surface of the bowl have opposing engaging surfaces which are inclined and downwardly converging. The inclined surfaces allow the slip to move vertically and radially relative to the bowl. In effect, the inclined surfaces serve as a camming surfaces for engaging the slip with the pipe. Thus, when the weight of the pipe is transferred to the slips, the slips will move downwardly with respect to the bowl. As the slips move downward along the inclined surfaces, the inclined surfaces urge the slips to move radially inward to engage the pipe. In this respect, this feature of the spider is referred to as “self tightening.” Further, the slips are designed to prohibit release of the pipe string until the pipe load is supported by another means.
In the makeup or breakup of pipe strings, the spider is typically used for securing the pipe string in the wellbore. Additionally, an elevator suspended from a rig hook is used in tandem with the spider. The elevator may include a self-tightening feature similar to the one in the spider. In operation, the spider remains stationary while securing the pipe string in the wellbore. The elevator positions a pipe section above the pipe string for connection. After completing the connection, the elevator pulls up on the pipe string to release the pipe string from the slips of the spider. Freed from the spider, the elevator may now lower the pipe string into the wellbore. Before the pipe string is released from the elevator, the spider is allowed to engage the pipe string again to support the pipe string. After the load of the pipe string is switched back to the spider, the elevator may release the pipe string and continue the makeup process.
Traditionally, a spider is located above a rotary table situated in the rig floor. More recently, flush mounted spiders have been developed so that the spider does not intrude upon the work deck above the rotary. Because flush mounted spiders reside within the rotary table, the pipe size handling capacity of the spider is limited by the size of the rotary table. Current spider designs further augment the problem of limited pipe size handling capacity. Thus, in order to handle a larger pipe size, a larger rotary table must be used. However, the process of replacing the existing rotary table is generally economically impractical.
Another drawback of some spiders currently in use is the guide plate for facilitating the axial movement of the pipe string. The guide plate is typically designed for use with a certain pipe diameter size. Therefore, the guide plate must be replaced when a different pipe size is used. Further, many spiders have slips that are held in position in the bowl by friction. As a result, only a limited amount of torque may be applied before slippage occurs between the slip and the bowl.
There is a need, therefore, for a gripping apparatus with increased pipe size handling capacity. There is a further need for a gripping apparatus having a guide plate capable of accommodating one or more pipe size. There is a further need for a gripping apparatus with increased torque capacity.
The present invention generally provides a gripping apparatus for supporting a tubular. The apparatus includes a housing having a longitudinal opening extending therethrough. A bowl is formed on an inner wall of the housing to provide an incline surface for one or more gripping members. As the gripping members are move down along the incline, the incline causes the gripping members to move radially toward the tubular and contact the tubular. In one embodiment, the housing comprises two body portions coupled together using one or mores hinges.
In one aspect, the bowl is formed as a recess in the inner wall of the housing. The hinges of the housing are progressively curved to accommodate the recess bowl, thereby increasing the tubular size handling capacity of the gripping apparatus.
In another aspect, the apparatus may include one or more guide keys disposed on the surface of the bowl. The guide keys mate with guide slots formed on an outer surface of the gripping members. The guide slot and guide keys minimize the rotational movement of the gripping members relative to the housing.
In another aspect still, the apparatus may a leveling ring connected to the one or more gripping members for synchronizing the movement of the one or more gripping members. The leveling ring may include one or more guide bearings movable along a guide track formed on an inner wall of an upper portion of the housing.
In another aspect still, the apparatus may include includes a flange for mounting to a rotary table. In another embodiment, the flange may include one or more blocks for mating with a rotary table. The one or more blocks minimize the rotational movement of the gripping apparatus with respect to the rotary table.
In another aspect still, the apparatus may include a cover assembly selectively attachable to the housing. The cover assembly may comprise two portions, each attachable to a respective portion of the housing. The cover assembly has a hole coaxially aligned with the opening of the housing.
In another aspect still, the apparatus may include one or more guide rollers to facilitate movement of the tubular within the housing. Preferably, the one or more guide rollers are positioned around the hole of the cover assembly in a manner capable of centering the pipe. In another embodiment, the one or more guide rollers are adjustable to accommodate different sized tubulars. In the preferred embodiment, the guide rollers include a clevis having a shaft at one end, a pin for coupling a roller to the clevis, and a mounting assembly. More preferably, the shaft is adjustable within the mounting assembly.
So that the manner in which the above recited features of the present invention, and other features contemplated and claimed herein, are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
a is an exploded view of the curved hinges of the body shown in
a-d is a sectioned view of the individual hinges of
The body 10 of the spider 100 is formed by pivotally coupling two body sections 11, 12 using one or more connectors 35. Preferably, hinges 35 formed on both sides of each body section 11, 12 are used to couple the two body sections 11, 12. Alternatively, the body sections 11, 12 may be hinged on one side and selectively locked together on the other side. A bowl 25 extends vertically through a lower portion of the body 10 to house gripping members 20 such as a slip assembly 20 as shown in
As further shown in
a-d show the hinges 35S-V in detail, respectively. The uppermost hinge 35S is the most curved hinge because the upper portion of the bowl 25 is the most recessed. As the recess of the inner wall 42 decreases toward the bottom of the bowl 25, the curve in the corresponding hinges 35S-V also progressively taper out. The curved hinges 35 allow the hinges 35 retain their capacity to support the pins 40 used to couple the two body sections 11, 12 together. The recessed bowl 25 places the slips 20 further away from the center of the spider 100, thereby creating a larger inner diameter to accommodate larger sized pipes. For example, it has been found that for a 37.5 inches rotary table, a spider having a recessed bowl with curved hinges may handle a pipe size up to about 20 inches. Whereas, a typical spider without curved hinges may only handle a pipe size up to about 14 inches. Therefore, aspects of the present invention increase the pipe size handling capacity of a spider disposed in a given rotary table size.
In another aspect, the bowl 25 of the spider 100 may include one or more guide keys 45 for guiding the axial movement of a slip 20. As illustrated in
In another aspect, one or more abutments 50 may be attached to a lower portion of the flange 30 of the body sections 11, 12 as illustrated in
In another aspect, the spider 100 may include a leveling ring 55 for connecting one or more slips 20 and synchronizing their vertical movement. As seen in
As shown in
The spider 100 may further include a cover assembly 15 for the body 10. The cover assembly 15 may comprise two separate sections attached above a respective body section 11, 12. The sectioned cover assembly 15 allows the body sections 11, 12 of the spider 10 to open and close without removing the cover assembly 15. The sections of the cover assembly 15 form a hole whose center coincides with the center of the body 10.
The cover assembly 15 may include one or more guide rollers 80 to facilitate the movement and centering of the pipe in the spider 100. Preferably, the guide rollers 80 are attached below the cover assembly 15 and are adjustable. The guide rollers 80 may be adjusted radially to accommodate pipes of various sizes. In one embodiment, the guide rollers 80 may comprise a roller 84 having a pin 86 coupled to a clevis 82. The clevis 82 may include a shaft 88 insertable into a mounting device 90 for attachment to the cover assembly 15. The shaft 88 is adjustable within the mounting device 90 to extend or retract the rollers 80 with respect to the mounting device 90. Preferably, the spider 100 has four roller guides 80 spaced equally apart around the center of the cover assembly 15.
In operation, spider 100 is flush mounted in rotary table. Before receiving the tubular, the guide rollers 80 are adjusted to accommodate the incoming tubular. Initially, the slips 20 are in a retracted position on the bowl 25. After the tubular is in the desired position in the spider 100, the piston and cylinder assembly 70 is actuated to move the slips 20 down along the incline of the bowl 25. The slips 20 are guided by the guide keys 45 disposed on the bowl 25. The incline causes the slips 20 to move radially toward the tubular and contact the tubular. Thereafter, the make up/break up operation is performed. To release the slips 20 from the tubular, the piston and cylinder assembly 70 is actuated to move the slips 20 up along the incline, thereby causing the slips 20 to move radially away from the tubular.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application is a continuation of co-pending U.S. patent application Ser. No. 10/207,542, filed Jul. 29, 2002. The aforementioned related patent application is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10207542 | Jul 2002 | US |
| Child | 10999520 | Nov 2004 | US |
