Method of and apparatus for continuous non-destructive testing of bar-shaped specimens

#The present invention is directed to a method of and apparatus for continuous non-destructive testing of bar-shaped specimens formed having iron-containing material of specific quality characteristics. Individual specimens are moved at a definite translational velocity along an elongated path through a testing block which is coupled to an electronic testing installation for continuously comparing the specimens passing through the testing block via the electronic testing installation with calibrated artificial flaws of a defined magnitude previously stored in the testing installation. The specimens are classified based on the comparison afforded by the testing installation.

#Bar-shaped specimens, particularly in the form of pipes or tubular members, are examined, during the course of a continuous passage, in accordance with preset standards in order to determine the presence or absence of flaws for assuring the quality characteristics described in an applicable specification. Mainly the testing processes used are based on magnetic induction or on acoustics. In both cases, a testing block is coupled to an electronic testing installation which has been calibrated with the help of a testing standard containing artificial flaws of a defined magnitude. When the testing standard is introduced into the testing block, the artificial flaws generate characteristic signals due to a change in the magnetic field (magnetic induction process) or by reflection (acoustic process). The amplitude level of the signals is arranged by suitable actuation links in the testing installation so that two response ranges are formed and assigned respectively to specific sorting compartments or trays in a sorting station. In the sorting station one sorting compartment receives accepted specimens while the other sorting compartment receives rejected specimens, that is specimens with a certain level of flaws.

#The specimens, such as pipes, are located in a supply station which also serves as a material buffer, and are consecutively displaced from the supply station onto a roll table and conveyed therealong at a specific translational velocity through the testing block. Any specimen generating signals of an amplitude level in the testing block--electronic testing installation, equal to or larger than the amplitude level of the testing standard, are stored in the sorting compartment for defective specimens after they have passed through the testing block. Specimens causing no amplitude or amplitude levels lower than that of the testing standard, are stored in the sorting compartment for flaw-free specimens.

#FIG. 1 is a schematic view of the invention.

#In FIG. 1 a supply station 1 contains a number of specimens in the form of pipes. The supply station 1 acts as a material buffer if it is connected to a manufacturing installation.

#A roll table 2 with a regulatable velocity, extends from the supply station 1 to a sorting station 3 and forms a testing path for the specimens. Sorting station 3 includes an accepted specimen tray or compartment 4, a rejected specimen tray 5 for a flaw type A of the specimen which can be reworked, a rejected specimen tray 6 for a flaw type B of a specimen which can also be reworked, and a rejected specimen tray 7 for specimens which cannot be reworked and thus constitute rejects or scrap. Between the supply station 1 and the sorting station 3 along the testing path there are two testing blocks 8, 9 separated in the testing path direction by a spacing X. The spacing between the testing blocks 8, 9 can be changed and they are decoupled from one another mechanically but are logically interconnected through an electronic testing installation 10 for evaluating the signal type as well as the signal location with reference to the length of a specimen. Block diagram 30 is a schematic illustration of the adjusting means for adjusting the spacing between the first and second testing blocks (8, 9).

#When a specimen is removed from the supply station 1 and moves individually along the roll table 2, initially it is transported by the table through the first testing block 8. If the specimen does not generate a flaw signal in the first testing block 8, then the downstream or second testing block 9 remains inactive and, upon reaching the sorting station, the specimen is directed into the accepted tray 4. The sorting operation is effected by an appropriate interconnection of the sorting station 3 with the electronic testing installation 10.