Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This application is a division of Canadian patent
application Serial No. 296,905 filed February 15, 1978.
sAcKGRouND OF THE INVENTION
Field_of the Invention
This invention relates to a joint sensor for sensing
the tool joint between pipe stands in a drill string.
Description of the Prior Art
Manually operable power tongs to effect the making and
breaking of joints between elements o~ a drill string are known
in the art. The tongs manual control console usually is
provided with four levers, each of which controls a pilot valve
of a small four-section stack valve. Each pilot valve controls
one main ~unction of the commonly utilized tongs structure.
For example, one valve controls the opening and
closing of the backup tong. A second valve controls the tongs
motor to rotate the power driven tong. The lift speed of the
tongs is controlled by a third valve, while a fourth valve
controls the upward or downward movement of the tongs lift. Of
course ! other tongs functions as, for example, the extension of
the stabber (if one is provided) or the extension of a joint
sensor would require a manual valve for the operation of each.
It wouId be advantageous to automatically control a
power tongs arrangement by utilization of an electrical tongs
control system. However, if an electrical control system is
utilized, lt is necessary to provide a suitable electro-
hydraulic interface to permit valves which are manually
operable to be operable in response to electrical signals output
from the control system. Further, to locate the power driven
and backup tong in a predetermined operating relationship with
respect to the tool joint, a joint sensor arrangement is
advantageously utilized.
SUMMARY QF THE INVENTION
This invention discloses a method and apparatus for
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sensing a distended location tsuch as a box end taper) on a
drill pipe.
The invention in this divisional application in one
aspect pertains to apparatus for sensing a distended location on
the exterior surface of a drill pipe, comprising a sensor
arrangement including an arm contactable with the exterior
surface of a drill pipe and pivotally movable with respect
thereto from a first, normal position to a second, deflected,
position. Means are provided for positioning the sensor
arrangement relative to the pipe exterior to dispose the arm in
contact with the drill pipe and m~ans actuated by the arm in the
second position provide for generating an electrical signal when
the arm is deflected a predetermined angular amount from the
normal position by a distended location of a predetermined
diameter on a drill pipe.
The invention also comprehends apparatus for precisely
locating the bevel of a box shoulder of a tool joint in which
the distance between that bevel and a predetermined diameter on
the box and elevator upset is a precise length. The apparatus
includes means for sensing a diameter of predetermined size on
the box end elevator upset of a tool joint and means, actuated ;~- ;
by the sensing means, for generating an electrical signal in
response to the detection of such a predetermined diameter by
the sensing means. Apparatus is provided for positioning the
sensing means adjacent the periphery of a pipe wall having a box
end elevator upset therein including means for moving the
sensing means in a first direction parallel to the axis of a ~
length of pipe, means for moving the sensing means in a second ~ ;
direction perpendicular to the axis of a length of pipe, and
means for contacting a length of pipe for guiding the sensing
means for movement in a third direction perpendicular to the
axis of a length of pipe.
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BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the
following detailed description thereof, taken in connection with
the accompanying drawings, which form a part of this
specification, and in which:
Figures lA and lB are, respectively, side and top
views of a joint sensor embodying the teachings of this
invention; and,
Figure 2 is a definitional diagram of two commonly
utilized drill pipe sections.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
Throughout the ~ollowing description, similar
reference numerals refer to similar elements in all Figures of
the drawings. Referring to Figures lA and lB, respectively
shown are side elevational and top ~iews of a joint sensor
generally indicated by reference nurneral 1025, embodying the
teachings of this invention. The joint sensor 1025 is attached
beneath the backup tong of a power tongs assembly and is
operative to accurately position the backup tong and a driven
tong (not shown) in a symmetrical relationship with the tool
joint being made-up or broken-out by the tongs under the control
of a tongs-control system. A suitable tongs control system is
disclosed in the parent application Serial No. 296,905 and
Divisional A thereof, Serial No. 399,891. Since the gripping
space for the tongs dies is limited, and since considerable
force must be applied to these dies, it is necessary to locate
the backup tong and the driven tong as nearly as possible in
vertical symmetry above and below a horizontal plane extending
through the tool joint.
The joint sensor 1025 includes a sensor arrangement
1204 which comprises an arm 1206 having a roller 1203 thereon,
the roller being contactable with a drill pipe and the arm being
pivotally moveable with respect thereto from a first, normal,
position to a second, deflected, position. The sensor
arrangement 120~ also comprises means 1210, including a limit
switch, associatecl with the arm 1206 for generating an
electrical signal on an output line 1060 (JOINT SENSED) when the
arm 1206 is pivotally deflected a predetermined angular distance
from the normal position by being brought into contact with a
distended location on the pipe. The arm 1206 is biased into the
normal position by an internal spring assembly ~not shown). The
means 1210 may be any suitable commercially available assembly,
such as that sold by Mirco under model number BZLN-2-RH.
*denotes trade mark
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In Figures lA and ls~ the joint sensor arrangement
1204 of the sensor 1025 is mounted on a carriage 1212 disposed
for movement within a suitable housing 1214. The housing 1214
is connectable by any suitable attachment arrangement 1216 to
the underside of the backup tong. Disposed within the housing
1214 is a piston-cylinder arrangement 1026. The piston-
cylinder arrangement 1026 is in fluid communication with a line
1027 illustrated diagrammatically on Fig. lA, the line 1027
carrying a fluid, such as pressurized air, which when provided,
extends the joint sensor from a first, horizontally retracted,
position to a second, horizontally extended, position. Included
within the piston-cylinder 1026 is the limit switch 1057 which
outputs an electrical signal on a line 1058 (JOINT SENSOR
RET~ACTED) to a tongs control system when the sensor 1204 is in
the horizontally retracted position. The cylinder 1026 may
provide a stroke greater than is necessary to extend the sensor
1204 to contact the pipe whose joint is to be sensed to provide
an additional ability to follow any longitudinal misalignments
of the pipe or irregularities in its surface, as with pipes
exhibiting an external upset ~Figure 2). The pressure of the
pressurized air in the line 1027 is sufficient to hold the
e~tended sensor 1204 in position against the pipe. It is most
advantageous to use a compressible fluid, such as pressurized
air, so that the pressurized air in the piston cylinder 1026
acts as a spring to allow movement of the sensor 1204 after it
is extended.
The carriage 1212 has horizontal roller elements 1218
engageable with guide rails 1220 (1220A and 1220B) mounted
within the housing 1214. The horizontal rollers 1218 are
provided to facilitate the horizontal movement of the sensor
1204 and carriage 1212 thereof in response to actuation of the
piston-cylinder 1026.
In one embodiment of the invention, the carriage 1212
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is provided with a pair of guide rollers 1222~ and 1222B. As
shown in Figure ls, the axes of rotation of each of the guide
rollers 1222 define a predetermined angle 1224 of approximately
120 degrees therebetween. The angularity be~ween the guide
rollers 1222 assists in centering the sensor 1204 laterally with
respect to the pipe. Centering springs 1226A and 1226B are also
provided between the guide rails 1220 and the housin~ 1214 to
permit the guide rollers 1222 to align the sensor 1204 with the
pipe although the pipe may not be centered within the tongs. In
an alternate embodiment of this invention, the guide rollers
1222 and the detector roller 1208 may each be of a predetermined
lateral dimension and in a parallel relationship so as to be
able to contact the pipe regardless of the centered orientation
thereof with respect to the tongs. In such a structural
embodiment, the carriage 1212 is moved horizontally from the
retracted to the extended position by the piston-cylinder 1026
and lateral centering of the sensor 1204 on the pipe is not
required.
In operation, the sensor roller 1208 moves with the
tongs slowly upwardly until the arm 1206 is pivotally deflected
from its normally outwardly biased position against the
surface of the pipe by a distended surface feature on the pipe.
With reference to Figure 2, it is there shown that dependent
upon the pipe utilized, any one of a predetermined number of
distended portions on the pipe may be used to actuate the
sensor arrangement embodying the teachings of this invention.
The location of the box end taper (Figure 2) having a
predetermined diameter of approximately 5.70 inches when using
5.00 inch drill pipe is such a convenient location on the pipe.
When the predetermined location on the pipe is encountered by
the sensor roller 1208 and the arm 1206 is pivotally deflected
from the normal position, the switch of means 1210 emits an
electrical signal on the line 1060 that the joint has been
sensed. When the predetermined location on the pipe is
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encountered, the distance 1230 ~rom that location to the joint
is a known value. The tongs lift is then stopped, the sensor is
retracted, and the backup tong is locked.
Due to the standardi~ation of drill pipes in the oil
drilling industry, detection of a predetermined loca-tion, such
as a predetermined diameter on the box end taper, insures that
any other surface feature on the pipe, such as the joint itself,
is then a predetermined known distance 1230 from the location
which generated the deflection signal. Thus, it is insured that
the tongs are in the operating position, that the backup tong
and the driven tong are vertically symmetrical with respect to
a horizontal plane through the pipe joint and that the joint may
be made-up or broken-out by the tongs.
With reference to Figure 2, shown are views of
standard drill pipe stands having the commonly named portions
thereof indicated as shown. Each end of each pipe stand
illustrated has a distended joint portion thereon. One end of
the stands ncludes a threaded male member while the opposite
end thereof is an internally threaded female member. Normally,
the pipe stand is inserted into the drill string such that the
male end of each stand is inserted into the bore before the
female end thereof. The male end of the next-to-be engaged
stand is then connec-ted by a power tongs to the protruding
female member of the last inserted stand protruding from the
bore.
Below the tool joint outer diameter, a taper portion
known as the box end taper and the pin end taper, respectively,
are provided on the female and male ends of the stands.
Depending upon whether an internal or external upset is ~
provided, further tapering of the drill pipe stand may occur. ~ -
The difference between an internal and external upset pipe stand
is illustrated in Figure 2. Basically, an internally upset pipe
presents a constant outer diameter between each of the end
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tapers while an externally upset pipe exhibits an upset taper on
the exterior of the pipe stand. In order to accommodate either
internally or externally pipe stands, the joint sensor 1025
embodying the teachings of this invention is operative to emit a
signal when the roller 1208 and arm 1206 thereof comes into
abutting contact with and is deflected by a predetermined
location on the box taper. Of course, any predetermined
location on the end taper sections, either on the internally or
externally upset pipe stand, may be detected by a joint sensor
1025, embodying the teachings of this invention.
Having described a preferred embodiment of the
invention, those skilled in the art may appreciate that
modifications may be imparted thereto yet remain within the
scope thereof as defined by the appended claims.
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