GB2134255A

GB2134255A - Method and apparatus for ultrasonic examination of taper pipe threads

Info

Publication number: GB2134255A
Application number: GB08300835A
Authority: GB
Inventors: Yaropolk Miroslavovic Bazhaluk; Oleg Mikhailovich Karpash; Ivan Grigorievich Migal; Fedor Ivanovich Turko
Original assignee: IVANO FRANKOVSK I NEFTI GAZA
Current assignee: IVANO FRANKOVSK I NEFTI GAZA
Priority date: 1983-01-13
Filing date: 1983-01-13
Publication date: 1984-08-08
Also published as: FR2540248A1; DE3301329C2; DE3301329A1; GB8300835D0; FR2540248B1; GB2134255B

Abstract

A method of ultrasonic examination of taper pipe threads comprises transmitting ultrasonic oscillations into the body of a pipe 3 through an end face 1 of a taper thread 2 of the pipe 3. One-half of the aperture angle phi r of the beams of the ultrasonic oscillations is equal to the angle of taper of the taper thread 2 of the pipe 3. In an apparatus for carrying out the abovedescribed method a device 9 for gripping the pipe 3 comprises a guide member 6 on which are mounted rollers 10 and 11 installed at right angles to the guide member. The roller 10, which is installed on the taper thread 2 of the pipe 3, is rigidly connected to the guide member 6 and is tapered with an angle of taper equal to the angle of taper of the taper thread 2 of the pipe 3. The rollers 11 are cylindrical in shape and are operatively connected to the taper roller 10 for movement along the guide member 6 and for engaging the end face 1 of the taper thread 2 of the pipe 3. <IMAGE>

Description

SPECIFICATION Method and apparatus for ultrasonic examination of taper pipe threads The invention relates to methods of non-destructive control of quality of materials and products and for apparatus for carrying out such control, and more specifically it deals with methods and apparatus for ultrasonic examination of taper pipe threads.

The invention may be used for inspecting taper threads of heavy-duty drill pipes, especially those of large-diameter pipes with a wall thickness up to 90 mm as well as for other types of pipes with taper threads.

It is an object of the invention to provide a method for ultrasonic examination of taper pipe threads which makes it possible to inspect taper pipe threads, especially in large-diameter pipes with a wall thickness up to 90 mm.

Another object of the invention is to provide a method for ultrasonic examination of taper pipe threads which also enables an improvement of the reliability of the examination.

Still another object of the invention is to provide an apparatus for ultrasonic examination of taper pipe threads for carrying out the abovementioned method, which enables an accurate orientation of the apparatus with respect to the pipe thread.

The invention substantially resides in that in a method of ultrasonic examination of taper pipe threads ultrasonic oscillations are transmitted into the pipe body through an end face of the taper pipe thread, one-half of the aperture angle of the beam of the transmitted ultrasonic oscillations being equal to the angel of taper of the taper pipe thread, the ultrasonic oscillations being transmitted are scanned over the primeter of the end face of the taper pipe thread, and the ultrasonic oscillations reflected from a flaw in the taper thread are received and used to assess the flaw.

The invention also resides in that in an apparatus for ultrasonic examination of taper pipe threads for carrying out the abovementioned method, comprising a guide member on which are mounted a piezotransducer, pipes for supplying a couplant fluid and a device for gripping the pipe, the device for gripping the pipe comprises rollers which are installed on the guide member at right angles thereto, one of the rollers, which is installed on the taper pipe thread, being rigidly connected to the guide member and being tapered with an angle of taper equal to the angle of taper of the taper pipe thread, the other rollers being cylindrically in shape and being operatively connected to the taper roller for moving along the guide member for engaging the end face of the taper pipe thread.

The piezotransducer is preferably installed on a carriage which is mounted on the guide member for movement and for adjustment with respect to the taper roller, the piezotransducer being pivotally secured to the carriage for oscillations in the longitudinal planes extending through the pipe.

This construction of the aparatus for ultrasonic examination of taper pipe threads for carrying out the method according to the invention makes it possible to inspect taper pipe threads, especially in large-diameter pipes with a wall thickness up to 90 mm, to improve the reliability of examination and to provide for an accurate orientation of the apparatus with respect to the pipe thread.

The invention will now be described with reference to a specific exemplary embodiment shown in the accompanying drawings, in which: Figure 1 is a longitudinal section of an apparatus for ultrasonic examinations of taper pipe threads.

Figure 2 is the same apparatus as shown in Fig. 1, a view take along arrow A in Fig. 1; Figure 3 is the same apparatus as shown in Fig. 1, a view taken along arrow B in Fig. 1.

A method for ultrasonic examination of taper pipe threads consists in that ultrasonic oscillations are transmitted through an end face 1 (Fig. 1) of a taper pipe thread 2 of a pipe 3 into the pipe body. One-half of the aperture angle zp, of a beam of ultrasonic oscillations being transmitted is equal to the angle (p of the taper thread 2 of the pipe 3. The ultrasonic oscillations being transmitted are scanned over the perimeter of the end face 1 of the taper thread 2 of the pipe 3, and the ultrasonic oscillations reflected from a flaw in the taper thread 2 are received and used to assess the flaw.

One-half of the aperture angle Gr of the beam of the ultrasonic oscillations equal to the angle tp of the taper of the taper thread 2 of the pipe 3 is determined from a known formula in which one-half of the aperture angle p, of the beam of the ultrasonic oscillations is assumed to be equal to the angle zp of the taper of the taper thread 2 of the pipe 3: 0.61 C df = sin (p wherein (p is the angle of taper of the taper thread 2 of the pipe 3, deg.; d is the diameter of a piezoelement 4 of a piezo-transducer 5, mm; f is the working frequency of ultrasonic oscillations, MHz; C is the velocity of propagation of ultrasonic oscillations in the pipe body, m/s (cf.A.K.Gurevich, l.N.Ermolov "Ultrasonic Inspection of Welded Joints" (in Russian), Kiev, Tekhnicka Publishing House, 1972, p.14).

With this condition being fulfilled, the ultrasonic oscillations propagate in parallel with the bottom of roots of the taper thread 2 and, in case there is a flaw in the root, the ultrasonic oscillations will include a pulse carrying information on the presence of a flaw.

An apparatus for ultrasonic examination of taper pipe threads for carrying out the method comprises a U-shaped guide member 6 (Fig. 2) on which are mounted said transducer 5, pipes 7 for supplying a couplant fluid through hoses 8 and a device 9 (Fig. 1) for gripping the pipe 3.

The device 9 for gripping the pipe 3 comprises three rollers 10 and 11 installed on the guide member 6 at right angles thereto. One roller 10, which is installed on the taper thread 2 of the pipe 3, is rigidly connected to the guide member 6 and is tapered with an angle of taper (p equal to the angle of taper of the taper thread 2 of the pipe 3 (this roller will be further referred to as taper roller 10).

The two rollers 11 (Figs. 1, 2) are cylindrical in shape and are operatively connected to the taper roller 10 for moving along the guide member 6 for engaging the end face 1 (Fig. 1) of the taper thread 2 of the pipe 3.

The taper roller 10 is installed on an arm 1 2 by means of a bushing 1 3 and a pivot pin 14.

The arm 1 2 is, in turn, secured to the guide member 6. A shaft 15 with a handle 1 6 is secured to the guide member 6 on the side thereof opposite to the point at which the arm 12 is secured to the guide member.

The cylinrical rollers 11 are mounted on an arm 1 7 which is installed for movement on the guide member 6. The arm 1 7 (Fig. 2) is connected to the arm 1 2 by means of springs 18, and its movement along the guide member 6 is limited by a stop plate 1 9. A shaft 20 with a handle 21 is secured to the guide member 6 (Fig. 1) on the side opposite to the point at which the arm 1 7 is secured to the guide member.

The piezotransducer 5 is installed on a carriage 22 which is mounted on the guide member 6 for movement and for adjustment with respect to the taper roller 10, the piezotransducer being pivotally secured to the carriage for oscillations in longitudinal planes extending through the pipe 3.

The piezotransducer 5 comprises the abovementioned piezoelement 4 which is connected to a flaw detector (not shown in the drawings) as it has no bearing on the invention by means of a cable 23. The piezoelement is cemented to a damper 24 and is housed in a casing 25.

A sleeve 26 is incorporated in the carriage 22 and has a guard 27 and a pivotal joint 28 in which is installed the transducer 5. The carriage 22 (Fig. 3) has two retainer screws 29 and 30 of which one screw 29 is designed for fixing the carriage 22 with respect to the taper roller 10, and the other screw 30 is designed for adjusting the angle of incidence of ultrasonic oscillations upon the body of the pipe 3 through the end face 1 of the taper thread 2.

The springs 18 are secured to the guide member 6 and arm 1 7 by means of posts 31.

The apparatus for ultrasonic examination of taper pipe threads for carrying out the method functions in the following manner.

The arms 1 2 and 1 7 to which are secured the taper roller 10 and the cylindrical rollers 11 for engaging the end face of the taper thread 2 of the pipe 3 are spaced apart by manipulating the handles 16 and 21 (Fig. 1). The rollers 10 and 11 are urged by the springs 18 as the arm 17 with the cylindrical rollers 11 and handle 21 can move along the U-shaped guide member 6 relative to the taper roller 10. The arm 12 carrying the taper roller 10 is rigidly secured to the U-shaped guide member 6.Thus the taper roller 10 is placed on the thread 2, and the rollers 11 are placed on the cylindrical potion of the pipe 3 so that during the examination of the threaded male portion of the pipe the taper roller 10 is on the outer threaded surface of the pipe and during the examination of the threaded female portion, on the inner threaded surface of the pipe.

When the apparatus is installed on the taper thread 2 of the pipe 3, the transducer 5 is on the side of the end face 1 of the thread 2 of the pipe 3.

A couplant fluid is fed through the hoses 8 (Fig. 2) and through the pipes 7 to the zone of transmission of ultrasonic oscillations.

The piezotransducer 5 (Fig. 1) is then installed on the end face 1 in such a manner that no signals from the bottom of the thread roots should be seen on the flaw detector display screen (not shown). As the carriage 22 (Fig. 3) with the transducer 5 is locked by the screw 29 in a fixed position with respect to the taper roller 10, when the apparatus according to the invention is caused to move along the perimeter of the thread 2 (Fig. 1), the ultrasonic oscillations transmitted by the transducer 5 will always pass at one and the same distance from the bottom of roots of the thread 2. This makes the examination results more reliable.

The inspection is also made more reliable owing to the fact that the transmission diagram of the piezotransducer 5 is chosen in such a manner that one-half of the aperture angle , is equal to the angle of taper of the thread 2. In this case the ultrasonic oscillations propagate in the pipe 3 in parallel with the bottom of the roots of the thread 2. The calculation is made in accordance with the abovegiven formula: 0.6 C df= sin g As the ultrasonic oscillations; propagate in the vicinity of the piezoelement 4 almost without spreading, there is provided a mechanical barrier in the form of the material of the casing 25 of the transducer 5 downstream the piezoelement, the thickness of the casing material being chosen appropriately to correspond to the near field (Fresnel field).In this case the ultrasonic oscillations propagate in the body of the pipe 3 in parallel with the bottom of the roots of the thread 2, beginning from the end face 1.

During the examination of the threaded portion the transducer 5 is at one and the same distance from the bottom of the roots of the thread 2 even with varying thickness of the pipe 3 since the transducer is in a fixed position with respect to the taper roller 10 which runs over the surface of the thread 2 during the examination.

In case of a wear of the end face of the thread 2, when it deviates from the position at right angles to the longitudinal axis of the pipe 3, the angle of incidence of the ultrasonic oscillations may change. For adjusting the angle of incidence of ultrasonic oscillations in such applications, the transducer 5 can oscillate in longitudinal planes extending through the pipe 3 owing to the provision of its mounting pivotal joint 28 which is retained in the carriage 22 by means of the screw 30 (Fig. 3).

The apparatus for carrying out the method may be used for inspecting taper pipe threads in all sizes of drill pipes as the cylindrical rollers 11 (Fig. 1), which are operatively connected to the taper roller 10, may be spaced apart from the latter over a distance equal to the length of the Ushaped guide member 6 which, in turn, is made in accordance with the thickness of the wall of the pipe 3.

For inspecting drill pipes with different angles of thread taper, an appropriate taper roller 10 should be used.

The apparatus for ultrasonic examination of taper pipe threads for carrying out the method makes it possible to inspect taper threads of drill pipes of all sizes since the movable rollers enable measurements through wall thickness over the whole range of pipe sizes.

The apparatus is simple in design and reliable in operation. The improvement of the reliability of inspection in using the apparatus according to the invention in accordance with the method of the invention makes it possible to effect a timely rejection of pipes with flaws so as to improve the engineering and cost efficiency of well drilling process.

Claims

1. A method of ultrasonic examination of taper pipe threads, comprising transmitting ultrasonic oscillations into the pipe body through the end face of the taper pipe thread; one-half of the aperture angle of the beam of the ultrasonic oscillations being transmitted being equal to the angle of taper of the taper pipe thread; scanning the ultrasonic oscillations being transmitted over the perimeter of the end face of the taper pipe thread; and receiving the ultrasonic oscillations reflected from a flaw in the taper thread to assess the flaw thereby.

2. An apparatus for ultrasonic examination of taper pipe threads, comprising a guide member on which are mounted a piezotransducer, pipes for dupplying a couplant fluid and a device for gripping the pipe; the device for gripping the pipe cosmprising rollers installed on the guide member at right angles to the guide member; one of the rollers, which is installed on the taper pipe thread, being rigidly connected to the guide member and being tapered with an angle of taper equal to the angle of taper of the taper pipe thread; the other rollers being cylindrical in shape and operatively connected to the taper roller for movement along the guide member for engaging the end face of the taper pipe thread.

3. An apparatus as claimed in Claim 2, wherein the piezotransducer is installed on a carriage which is mounted on the guide member for movement and for adjustment with respect to the taper roller, the piezotransducer being pivotally installed on the guide member for oscillations in longitudinal planes extending through the pipe.

4. A method substantially as hereinabove described.

5. An apparatus substantially as hereinabove described with reference to, and as shown in the accompanying drawings.