US 3882377 A
The combination of a power driven pipe tong and a backup tong is supported upon a hoist mechanism to be positioned vertically with respect to the tool joints of a string of drill pipe. A magnetic eddy current detector is disposed adjacent to the drill pipe and produces a command signal to control the hoist mechanism and stop motion when the tong assembly is in a position at which the tool joint engaging jaws of the power tong and the backup tong are properly engageable with the tool joints.
Description (OCR text may contain errors)
United States Patent Kelly [1 1, 3,882,377 51 May 6,1975
, ' Inventor: Robert R. Kelly, Hoffman Estates,
 Assignee: Borg-Warner Corporation, Chicago,
 Filed: Apr. 19, 1974  Appl. No.: 462,276
Related US. Application Data  Division of Ser. No. 314,285, Dec. 12, 1972.
 US. Cl. 324/37  Int. Cl G0lr 33/12  Field of Search 324/37, 40
 References Cited UNITED STATES PATENTS 3,361,961 l/l968 Zoellick 324/37 3g //5 we we 6 Primary ExaminerRobert J. Corcoran Attorney, Agent, or Firm-Aubrey L. Burgess  ABSTRACT The combination of a power driven pipe tong and a backup tong is supported upon a hoist mechanism to be positioned vertically with respect to the tool joints of a string of drill pipe. A magnetic eddy current detector is disposed adjacent to the drill pipe and produces a command signal to control the hoist mechanism and stop motion when the tong assembly is in a position at which the tool joint engaging jaws of the power tong and the backup tong are properly engageable with the tool joints.
2 Claims, 8 Drawing Figures PATENIED HAY 5197s SHEET 3 OF .3
III/lil APPARATUS FOR SENSING ANOMALIES AT THE THREADED PIPE JOINTS OF A PIPE STRING USING A DOUBLE TELESCOPING PROBE This is a division of application Ser. No. 314,285 filed BACKGROUND OF THE INVENTION In the drilling of well bores, such as oil and gas wells, into the earth, and in other operations involving the completion, treatment or production of wells, a length of pipe is periodically round tripped. The drill string or string of pipe consists of stands which are made up of lengths of pipe, and the stands are successively made up or broken out of the string as the string is being run into and being removed from the well. During the drilling of the well, the well drilling pipe string is periodically round tripped for changing the bit at frequent intervals involving substantial labor and expense, and in order to facilitate the making up and breaking out of the so called tool joints between pipe stands, power tong apparatus has been developed comprising a power driven pipe gripping tong mechanism which is utilized in combination with a stationary backup pipe gripping tong mechanism engageable with the tool joint sections which are relatively rotatable to make up and break out the joints.
An example of such a combined power driven and backup. tong is shown and described generally in the pending application for Letters Patent filed in the name of C. D. Barron et al., Ser. No. 216,216, filed Jan. 7, 1972, for Power Tong Positioning Apparatus, now US. Pat. No. 3,780,815 issued Dec. 25, 1973, wherein the combined tong assembly is supported by a hoist mechanism so as to be positioned with respect to a string of drill pipe or the like, at a location at which the power operated pipe gripping mechanism and the backup pipe gripping mechanism are properly engageable with the tool joint sections.
In the manual control of such pipe tong positioning devices it is necessary that an operator visually correlate the tool joint with respect to the tong assembly as the latter is raised or lowered and be able to precisely position the tong assembly. However, it frequently occurs that the drilling and other well treating or producing activities are conducted during the night or during other periods when visability is poor. Moreover, in the case of an automated drilling system it would be necessary that the tong assembly be properly positioned with respect to the tool joint in a pipe string in an automatic and accurate manner.
SUMMARY OF THE INVENTION The present invention involves utilizing sensing means carried by or adjacent to the combined power driven and backup tongs of a vertically movable tong assembly, the sensing means being operable to provide a control signal whereby vertical movement of the tong combination is arrested at a location at which the power driven tong and the backup tong are properly positioned for engagement of the tool joint engaging tong jaws with the tool joint parts of the pipe joint.
More particularly, the present invention involves the utilization of a magnetic eddy current responsive sensing unit which is adapted to provide a control signal whereby the hoist mechanism for a combined power driven tong and backup tong is controlled to properly position the tongs with respect to the tool joint parts.
In a specific sense, in accomplishing the foregoing, a magnetic eddy current sensing means is carried by the combined power driven and backup tong assembly and includes a probe supported in close proximity to the pipe, whereby when the interface between a pair of tool joint parts is detected due to the discontinuity, a control signal is supplied to de-energize the hoist operating means so that the tongs will be properly positioned with respect to the tool joints.
The joint detector is biased to a position with respect to the pipe so that the sensing head is adapted to be uniformally closely positioned relative to the tool joint over a range of tool joint diameters to compensate for worn, undersized joints.
The tool joint detecting means may be combined with a set of power driven and backup tongs which are supported, by way of example, by the hoist mechanism of the aforementioned application for Letters Patent, Ser. No. 216,216, now Pat. No. 3,780,815 issued Dec. 25, 1973, or by other hoist mechanism which is adapted to be controlled in response to the control signal transmitted thereto by the sensing means.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary view in side elevation with parts of the tong assembly broken away to disclose a tool joint therein;
FIG. 2 is an enlarged fragmentary detail view illustrating a typical drill pipe tool joint, portions of the tongs being shown in broken lines;
FIG. 3 is an enlarged horizontal section between the power tong and backup tong of FIG. I, as taken on the plane of the line 3-3 of FIG. 1 and illustrating the disposition of the sensing means;
FIG. 4 is an enlarged fragmentary view in vertical section, as taken on the line 4-4 of FIG. 3',
FIG. 5 is an elevation of the end of the sensing means, as taken on the line 55 of FIG. 4;
FIG. 6 is a transverse section as taken on the line 6-6 of FIG. 4 and on a slightly enlarged scale;
FIG. 7 is a fragmentary detailed view in section as taken on the line 77 of FIG. 4 and on an enlarged scale; and
FIG. 8 is a schematic diagram showing the sensing means and the hoist controlling means.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there is shown hoisting apparatus for positioning a tong assembly T vertically with respect to a string of well pipe, such as well drilling pipe P having a joint .1 which interconnects the pipe stands. The hoist apparatus includes a vertically disposed column formed, in the illustrative embodiment, of an I- beam having a lower or base support 14, and an upper brace or support 12 is connected to the top of the column 10. Upper bearing means 16 and lower bearings means 18 provide a pivotal connection for the beam so that it can be rotated on a vertical axis and to enable the tong assembly T to be swung to and from a position aligned with the well bore.
A generally hollow and elongated rectangular support collar 20 is slideably disposed about the column 10 and is adapted to be moved upwardly and downwardly on the column 10. The collar 20 is supported for vertical movement on the column 10 by roller assemblies 22 incorporated within the collar 20. As shown, a plurality of flanged rollers 23 are included in each roller assembly 22 and are engageable with the inner faces of the flanges of the I-beam column to maintain the collar against cocking on the column. I A tong supporting yoke structure 24 is mounted on the collar 20 and projects horizontally therefrom, the yoke structure 24 supporting the pipe tong assembly T. This tong assembly, as is customary, includes a backup tong 26 and a power driven tong 30 interconnected together and mounted within a cradle assembly 32. An example of a power tong assembly T of the type generally disclosed herein is more particularly shown and described in the application for US. pat. Ser. No. 134,552, filed Apr. 16, 1972, in the name of Carl A.
I Wilms, abandoned in favor of copending continuationin-part application Ser. No. 216,182, filed Jan. 7, 1972,
in turn abandoned in favor of copending continuation I application Ser. No. 407,698, filed Oct. 18, 1973. In
such an assembly, the backup tong 26 is adapted to hold one section of a joint J in the pipe P against rotation while the power driven tong 30 engages the other joint section and rotates the same in a selected direction depending upon whether the joint is being made up or broken out.
Disposed adjacent to and extending vertically along side the column 10 is a power source 34 shown in the form of a hydraulic piston and cylinder actuator unit. The power source 34 is pivotally mounted at its lower endto the lower support 14 and has at its upper end a roller or sprocket 38 over which one or more roller chains 36 extend, the chains 36 being anchored at their lower ends to the lower support 14 and extending upwardly over the sprocket 38 to provide a downwardly extending run which is connected to the yoke structure 7 24. The arrangement of the hoist chain and piston cylinder unit is such that the movement of the tong assembly T is twice the movement of the power source so that the tong can be moved over a large vertical span without necessitating an equally long actuator.
In the use of the tong hoist when running the pipe string P, the tong is lowered to a location affording clearance for the pipe supporting elevator until the pipe in the well bore is supported by the usual slip mechanism and the elevator is released. A next stand of pipe is then stabbed into the upper end of the pipe string and the tong assembly T is elevated to a location at which the respective tongs are engageable with the tool joints. When retrieving or pulling the pipe string, the tong assembly T is also lowered to enable the elevator to be latched on or lowered onto the pipe string supported in the slips, and when successive joints are raised the tong assembly T is elevated by its hoist to enable the tongs to engage the tool joints, as more specifically described below.
The present invention is addressed to the problem of positioning the tong assembly T with respect to the pipe P so that the pipe gripping mechanism or jaws within the respective backup tong and power tong 26 and 30,
as shown in broken lines in FIG. 2 and designated 26a trieving of the pipe string from the well, it is, as pointed out above, hoisted or lowered in an elevator adapted to be hoisted by the usual drilling rig draw works, and the pipe string in the well is supported in the usual slip mechanism, while a length or stand of pipe is being broken. out of or being made up in the pipe string. During the period that the pipe string is not supported in the slips but is being moved by the elevator, thetong assembly T is normally lowered to an out-of-the-way location, but when the pipe string is supported in the slips thetong assembly T must be elevated to a position at which the pipe gripping jaws 26a and 30a are adapted to engage the tool joint sections 26b and 30b. Proper positioning of the tong assembly T with respect to the pipe T is difficult, at best, but the difficulty is increased when visibility is poor such as at night or during inclement weather. i l
Accordingly, the present invention involves the utilization of pipe joint detecting means M located between the backup tong 26 and power tong so as to scan the Y pipe as the tong assembly T is being elevated and detect a joint so as to cause the hoist mechanism to be deenergized when the tong assembly T is at its proper location.
As seen in FIG. 7 the joint detector means M is a magnetic eddy currentn detector device, such as the model ED-4OO MAGNATEST instrumentof Magnaflex Corporation, referred to above, incorporated in an assembly whereby the device is adapted to closely follow the pipe joint sections.
More particularly, the instrument M includes an elongated hollow case 100 suitably mounted on the backup tong assembly 26 as by releasable clamps or brackets 101, so that the overall disposition of the case 100 on the tong 26 can be adjusted radially with respect to the pipe opening 102 through the tong assembly. Other modes of supporting the case 100 may' be employed, including, if desired, means for retracting the case when the sensor is not in use and moving the outer surface 104 on which is longitudinally and slidand 30a, are adaptedto engage the respective joint secstring must be made up. During the running in and reably disposed a sleeve 105. Interposed between opposed shoulders 106 and 107 on the inner body 103 and the sleeve 105, respectively, is a coiled compression spring 108 which normally biases the sleeve 105 outwardly with respect to the case 100. The sleeve 105 is maintained in a predetermined orientation within the case by means of a suitable fixed pin 109 and pin receiving elongated slot 110 in the sleeve 105. Suitably affixed to the outer end of the sleeve is a sensing head 111, this head 111 rotatably supporting a pair of vertically and laterally spaced rollers 112 and 113 on axles 1 14, whereby the proximity of the head 1 l 1 to the pipe P and more particularly to the joint sections 26b and 30b is pre-determined, the spring 108 maintaining a bias on the sleeve 105 which causes the sleeve to be projected longitudinally from the case 100 to an extent limited by the length of the slot 110. The length of the slot 1 10 may be such that the outward extension of the sleeve 105 with respect to the case 100 is so limited that therollers 112 and 113 may not contact the reduced diameter or mid-section of the pipe P, but in any event the enlarged diameter coupling portions or tool joints 26b and 30b are engageably by the rollers 112 and 113, notwithstanding variations in the diameter of the tool joints which may be caused by wear.
Carried by the head 111 and extending telescopically into a bore 115 within the inner body 103 is a tubular support 116 which is adjustably threaded at 117 into the head 111 and contains a coil assembly 118 encapsulated within insulating body 119 and including coils C1 and C2 connected by conductors 120 and 121 respectively to the current inducing and detecting system hereinafter to be described, whereby the anomoly at the upper end shoulder 122a of the lower tool joint box 122 which is engageable with the anomoly at the downwardly facing should 124a on the pin end 124 of the upper pipe section causes a variation in the eddy current in the tool joint, whereby to establish a signal for interrupting operation of the hoist power means 34 when the tong assembly T is in the proper relationship to the tool joint as shown in FIG. 4, at which position, as seen in FIG. 2, the jaws 26a and 30a of the backup tong and power tong 26 and 30 respectively are engageable with the tool joints 26b and 30b.
The coils C1 and C2 are in circuit with the control means, as typical of the ED-4OO MAGNATEST instrument referred to above. Referring to FIG. 8 it will be noted that the coils C1 and C2 are connected to a bridge circuit containing the usual fixed and variable balancing resistances and connected to a power source 131. The output signal from the bridge circuit 130 is supplied to a tuned pre-amplifier 132, the output of which is supplied to an amplifier 133 which is adjustable by sensitivity control potentiometer means 134.
The output from the amplifier 133 drives a demodulator 135 to produce an output signal which is supplied to a meter 136. In addition, the undemodulated signal from the amplifier 133 is supplied to a threshold switch 137 containing a silicon rectifier which is adapted to be triggered when the undemodulated signal is at a predetermined level as, determined by a threshold switch adjustor potentimeter 138. When the threshold switch 137 is triggered, a relay 139 is energized to control operation of the hoist power source 34, and if is desired, a glow tube 140 may be in circuit with the relay 139 to indicate that it has been energized.
As also seen in FIG. 8, the hoist means 34 is adapted to be elevated by hydraulic fluid pressure supplied to a cylinder 34a beneath the piston 34b, under the control of a combined manual and automatically operated valving system. The valving system includes a pilot operated main value MV which is, for illustrative purposes, normally spring loaded to a position at which fluid pressure supplied from a supply conduit 141 is shut off from the actuator cylinder 34a and flows to tank at 142. At the same time pilot fluid pressure is exhausted to tank at 143 through a normally closed throttle valve TV via the pilot conduits 144 and 145, as shown in broken lines, and pilot pressure from a source conduit 146 is shut off at the valve TV.
When it is desired to exhaust pressure fluid from the actuator cylinder 34a the valve TV is shifted left, as seen in FIG. 8 to establish communication between the pilot pressure source 146 and the pilot conduit 144 so as to shift the main valve MV to the left as viewed in FIG. 8, whereby fluid pressure from the source 141 is supplied via a conduit 147 to a normally closed pilot valve 148 to open the latter and allow fluid to exhaust from the actuator cylinder 34a through the conduit 149 and thence to the tank at 142 through the main valve MV. When it is desired to elevate the tong assembly T by applying fluid under pressure to the actuator cylinder 34a, the throttle valve TV is shifted to the right, thereby applying pilot fluid pressure to the main valve and thereby shift it to the right to establish communication between the source conduit 141 and the conduit 149 leading to a back flow preventing valve 149a bypassing the pilot valve 148, which will effect elevation of the tong assembly T and hold it in the elevated position.
The main valve MV is also shiftable between its two positions from its center position by solenoid actuators under the control of a switching circuit generally denoted at 150 and including a down switching mechanism 151 and up switching mechanism 152. The down switching mechanism includes a down relay 153 which is adapted to be energized by a manual switch 154 so as to be latched in the energized condition by a holding switch 153k, so that contacts 155 are maintained to energize the solenoid 155a and move the main valve MV to the left as seen in FIG. 8. Correspondingly, the up switching mechanism 152 includes an up relay 156 adapted to be energized by a manual switch 157 which closes holding contacts 158 to maintain contacts 159 closed and energize the solenoid 159a of the main valve MV. Each of the down and up switching mechanisms 151 and 152 also includes a manual switch 155b and 159b, respectively adapted to manually energize the respective solenoids 155a and 159a in an overriding manner. Interposed in the circuit with the down and up relays 153 and 156 are respective switches 153a and 156a which may be suitably actuated to an open position to limit upward and downward motion of the tong assembly beyond a fixed range when the system is being controlled by the eddy current detector means M. Now it will be apparent that energization of the up and down switching circuitry 151 and 152 requires that the contacts 139a of the control relay 139 be closed to complete the circuit between a source conductor 13% and one side of the respective relays 153 and 156. If desired, the detector operated relay 139 or some other signal responsive means which is energized when the joint I is properly positioned in the tong assembly T, may be operated to effect actuation of the tongs 26 and I claim:
1. Apparatus for sensing anomalies at the threaded pipe joints of a pipe string along which the device is longitudinally moved comprising: an elongated case having a longitudinally extending cylindrical bore therein open at one end thereof, means for supporting said case normal to the pipe string with an open end of said case facing the pipe string and spaced a predetermined distance therefrom, an elongated cylindrical tubular body longitudinally positioned in the bore of said case and having a cylindrical, tubular end portion spaced inwardly from the wall of the cylindrical bore of said case to provide with said wall an annular cylindrical chamber open at said one end of said case, a sleeve received in said chamber for longitudinal sliding movement therein and having one end projecting from said chamber, resilient means biasing said sleeve outwardly of said chamber, means for limiting outward movement of said sleeve in said chamber, means for preventing rotation of said sleeve in said chamber, a head member affixed to said one end of said sleeve, a cylindrical tubular support longitudinally adjustably carried by said ing: releasable means for holding said case against longitudinal movement, said releasable means being releasableto permit longitudinal movement of said case to another position for adjustment of the spacing of said open end of said case from the pipe string, said releasable means then being re-engageable to hold said case in said another position.