Patent GB-959382-A (GB)
Title: Apparatus for inspecting pipe couplings or other cylindrical articles
Inventor: HARMON WILLIAM CLAIR
IPC: G01N22/02
Filed: 1960-09-15
Abstract: 959,382. Cleaning pipes. REPUBLIC STEEL CORPORATION. Sept. 15, 1960, No. 31800/60. Heading F2N. [Also in Division G1] In an apparatus for inspecting a pipe coupling or other cylindrical article for flaws by mounting the coupling or article so that it may be rotated and providing an electrical induction type flaw detector, supporting means are provided for the detector which enable the head to be moved into and out of a position adjacent to or in engagement with the outer surface of the article when mounted, and to traverse the length of the article whilst it is being rotated, Couplings are delivered to a biconical roller conveyer 11, Fig. 1, down which they roll under gravity to a coupling elevator 12 whereat they actuate a switch, the switch resulting in the actuation of a pneumatic elevator which lifts the coupling to a shoot 13 of a cleaning machine 14 and returns to its original position in response to the operation, by the coupling, of a switch in the shoot. The shoot delivers the coupling to a position in which it rides on a pair of motor-driven rolls 15, 16, and a cylindrical cleaning brush 19 rotated by a separate motor is lowered by a pneumatic mechanism to clean the outer surface, a spray of cleaning fluid being applied to the brush for the cleaning of each coupling, and an air nozzle being provided to blow dirt from the coupling as it is loosened. The cleaning head is retracted after a prescribed time and the coupling is lifted from the rolls by a pneumatic kick-out device to a shoot 22, down which it moves to the rolls 24, 25 of an inspecting machine 26. The sensing head is lowered to engage the outer surface, remains stationary for one revolution of the coupling, traverses the length of the coupling and is finally lifted from the far end after remaining stationary during a complete revolution. The coupling is lifted into a discharge shoot 31 by pneumatic discharge apparatus 30 and actuates a switch in the shoot, which according to whether a " defective coupling " circuit has been prepared during the test, permits the passage of sound couplings to container 32, or stops a defective coupling over an elevator 34. Defective couplings are lifted by the elevator to a discharge conveyer discharging into a second conveyer. The apparatus is controlled by pneumatic pistons through solenoid controlled valves which respond to switches which are actuated by the presence of the coupling or by moving parts of the apparatus, speed control valves being provided to regulate the timing. The walls of the various shoots and conveyers are made movable by manually controlled lead screws to deal with various lengths of coupling. Roll spacings are made adjustable to deal with various sizes of coupling, and provision is also made for modifying the travel of the cleaning and detecting heads. The timing of operations is referred to the initiation time and is controlled by speed control valves on the pneumatic cylinders. The roll drive motors for the cleaning and inspecting section run continuously whenever the machine is operating, and interlock arrangements are provided to prevent insertion or removal of a coupling whilst a head is lowered. Testing circuit-The sensing head which is provided with a sapphire shoe 377, Fig. 22, carries a coil 376 which is in the circuit of an H.F. oscillator 379, the output of which is fed back to effect level control and is also applied through amplifying demodulating, clamping and threshold circuits to operate a reject circuit relay 370 in the anode circuit of valve 403, a power amplifier 406 which includes a relay 397 having contacts in the grid circuit of valve 403 ensuring a rapid rise time and positive operation. The arrangement of biased amplifier 392, unbiased amplifier 393, and amplitude selector 394 discriminates against random pulses. Specifications 727,217, 747,388 and 870,487 are referred to.