Testing elongate round workpieces

(42) Date of commencement of the patent: 15. 5.1988 (45) Date of issue: 27.12.1988

<td>(30) Priority:</td><td>(73) Patent owner:</td>

<td>9. 4.1981 DE 3114850 claims.</td><td>MANNESMANN AKTIENGESELLSCHAFT D-4000 DUSSELDORF (DE).</td>

<td>(56) Documents:</td><td>(72) Inventor:</td>

<td>US-PS 3981184 US-PS 4217782 US-PS 3289468 US-PS 3570279</td><td>HAACKE HARRI ING. DUSSELDORF (DE). HOLE CARL DUISBURG (DE).</td>

(54) DEVICE FOR TESTING LONG-DRIVEN ROUND WORKPIECES, SUCH AS TUBES AND BARS, OF THEIR TOTAL LENGTH, MOVING IN THEIR LENGTH DIRECTION

CQ

AT 387 284

MH 0078313

Nr.387284

The invention relates to a device for testing elongate, round, helically moving, round workpieces, such as pipes and rods, over which

Overall length, in particular with ultrasound in segment immersion technique, on longitudinal and transverse defects and on wall thickness, with probes, which are arranged movable in the longitudinal direction of the workpiece and arranged radially adjustable to the workpiece.

From US-PS No. 3,289,468 a device for ultrasonic testing of pipes is known, in which the pipes to be tested are guided helically over a plurality of stationary arranged test probes.

US Pat. No. 3,911,184 describes a method for the coordinate representation of 10 defects in the ultrasonic testing of round material. While the test material rotates on the spot, for example, the movements of the test material and the probes are recorded separately, the determination of the location of errors then takes place in a computer.

Finally, from materials evaluatin (Jan. 1974, p.18 to 24) an associated testing system for small pipes is known, in which the test methods ultrasonic, eddy current and

Geometry measurement can be used as complementary method.

A disadvantage of all these known methods and devices that at the beginning of the tube and at the tube end by rotation and advancement of the tube resulting gussets remain unchecked. This means that these unchecked pipe ends must also be checked.

For small dimensions, to avoid unchecked end parts the shock-to-Stoß20 test is known, but here remains at the beginning of the first and at the end of the last tube, an unverprüfter gusset. Because of the axial and radial deviations, which are preferably present in hot-finished test specimens of larger dimensions, the shock-to-shock mode testing is technically not feasible. This also applies to pipes whose ends are provided with welding phases, since there is a risk of damage to the pipe ends in the shock-to-shock mode.

The object of the invention is to provide a device for testing elongated round material, such as pipes and rods, with the help of which the good to be tested can be checked properly at the beginning and end.

To solve this problem, the invention proposes that along the Längs30 direction of the workpiece independent, provided with identical drives probes are provided and that the probes are speed-dependent so controlled with respect to the movement of the workpiece, the speed of the test head in contact with the workpiece beginning and end is synchronous with the axial speed of the workpiece for at least one workpiece revolution. The advantages of erfindungsge35 MAESSEN device are that even with single piece test, the verification can be omitted, because tube top and end of the tube by synchronous mitbewegten test heads can be detected with.

In the drawings, a possible embodiment of a device according to the invention is shown schematically. FIGS. 1a to 1c show a longitudinal section through the transport system 40 of a test system with the positions shown for detecting the beginning and end of the test material.

2a to 2d, the representation of the path tracking of the test material by a test mechanism.

In Fig.la simplified mechanical part of a test system -1- is shown, in which the test material is transported about its longitudinal axis rotating on inclined radial rollers -7,8,9,10- in the axial direction. Between the radial rollers -7,8,9,10- test mechanisms 45 -4,5,6- are arranged, which moved parallel to Prüfgutlängsachse on an electric motor

Carriage -2- be moved in both directions.

The movement sequences of test specimens and test mechanisms are indicated in FIGS. 1 a to 1 c.

FIGS. 2a to 2d illustrate the path tracking of Prüfgutanfang and end by 50 one of the indicated in Fig.la to lc testing mechanisms. In Fig.2a, the rotating about its longitudinal axis Prüfgut the test mechanism -4- approaches. If the beginning of the test material reaches the position AI, then the entire test mechanism in the test material transport direction is set in motion.

- 3 No.387284

After a short acceleration distance S_b , ie after reaching the position Α I ', the

Test mechanism -4- raised, u.zw. computer controlled so that the rear end of the in the

Test mechanism housed probe or probe assembly just recorded the Prüfgutanfang.

The test mechanism -4- which is now in contact with the test material follows this with 5 equal axial speed for the duration of at least one Prüfgutumdrehung corresponding to the travel path S._pr to the position Α I ''. The synchronous movement of test material and test mechanism -4- avoids the untested gusset at the beginning of the test material.

The same process is repeated, as indicated in Fig.la, in the between the radial rollers -8,9,10- accommodated test mechanisms -5 and 6-.

So that the test mechanism -4- is back in its initial position for detecting the pipe end, it must after reaching the position Α I '¹ according to Fig.2b during the further Prüfgut transport slowly in the opposite direction to the position AI₄ to travel the distance (r). This is done computer-controlled with a speed that is proportional to the axial velocity of the test material.

Hiebei increases the relative axial velocity between test material and test mechanics.

This has the consequence that increases during the return movement of the test mechanism resulting from both movements feed over the given by the setting of the transport device feed. By choosing the magnitude of the return speed must be ensured that the given by the probe or probe assembly 20, taking into account a certain overlap - maximum allowable feed is not exceeded. This means that after standstill of the test mechanism, ie after reaching the position AI ,,, the test feed corresponds to that given by the transport device, which compared to the aforementioned maximum allowable feed has a smaller value.

Now reaches the end of the test material according to Figure 2c the position Ε I, the Prüfmecha25 nik -4- set again in Prüfgut-transport direction in motion. After passing through the acceleration section Sb detects the front end of the housed in the test mechanics probe or probe assembly the Prüfgutende, u.zw. computer-controlled after reaching the position Ε I '.

The test mechanism -4- follows the test material again with the same axial velocity for the duration of at least one Prüfgutumdrehung. Also here remains due to the synchronous movement no unverified gore. After reaching position Ε I '¹ according to the method Spr, the test mechanism -4- is lowered and according to Fig.2d at rapid speed to its original position AI₄ moved back along the route Sr, so that the test procedure can be initiated in the same way again at the following test specimen.

In Fig.la to lc the concept of a test system with three separately from each other, on slide -2- movable test mechanisms -4,5,6- shown. This corresponds, for example, to the construction of an ultrasonic test system, in which the test planes for longitudinal error, transverse defect and wall thickness measurement are accommodated in three separate test mechanisms -4, 5-6, which independently of one another complete the sequences of motion described in FIGS. 2a to 2d.

The accuracy of the complete detection of Prüfgutenden depends on the accuracy of the tracking of the test material. An exact direct path tracking helically transported goods is extremely expensive. The indirect tracking can be done, for example, by incrementation by means of a computer from path pulses of the drive units for Prüfguttransport.

It is based on constant conditions for feed per Prüfgutumdrehung and slip on drive wheels or pulse encoders, which are well-connected to the test, from. Since these factors are subject to certain fluctuations in practice, the tracking by test marks, for example, has to be controlled by light barriers immediately before each test mechanics and corrected if necessary.