GB1306535A - Performing operations in pipes - Google Patents

Abstract

1306535 Controlling vehicles SNAM PROGETTI SpA 11 March 1970 [11 March 1969] 11785/70 Heading B7H [Also in Divisions F2 G1 and H5] Apparatus for performing an operation such as cleaning, painting or weld radiography inside a pipe, is mounted on a carriage movable along inside the pipe, to a desired position along its length determined by a source of penetrative radiation, located outside the pipe at the desired position, which actuates a detector, mounted on the carriage, to cause stopping of the carriage and/or initiation of the operation. Radiography carriage, as shown in Fig. 1, has a battery carrier 8, pivoted to remain vertical and prevent electrolyte spillage, and coupled by lever 7 to steering arm 6 to provide automatic steering to avoid turning over at bends in the pipe. A gamma radiation source for radiography is automatically moved out from a cylindrical container 2 by an electromagnet to an irradiation position 4 where a 360 degrees collimating zone 5 is provided between shield 1 and container 2. Control circuit, Fig. 2.-Switch D or F is closed to apply power from battery B 2 to the electric motor M driving the carriage along the pipe through its rear wheels. On reaching the predetermined position, gamma radiation γ<SP>s</SP> from the external radioactive source is detected by a geiger counter mounted on the carriage. The output of the counter is integrated and causes energizing of relays R 1 and R 3 to stop the carriage. The external source is now removed. Relay R 3 is self-holding and so programmer P is allowed to execute the exposure sequence, causing energization of the electromagnet E which moves the radiography source S 1 . At the end of the exposure, relay R 3 is de-energized and motor M started again. The circuit includes an acoustic warning device A which produces a continuous signal during movement of the carriage and an intermittent one during the exposure period. Circuit modifications, Fig. 3 (not shown).- The detector output is integrated and feeds a monostable multivibrator determining the exposure cycle period. A further gamma source and further counter are used to stop and perhaps reverse the direction of running of the carriage. The first and further detectors are arranged to view upwardly and downwardly, respectively. Reference has been directed by the Comptroller to Specification 1,200,896.