Patent GB-1362580-A (GB)
Title: Pipeline crawler
IPC: G01M3/00
Filed: 1971-10-11
Abstract: 1362580 Automotive pipe-line crawler AUTOMATION INDUSTRIES Inc 11 Oct 1971 [12 Oct 1970] 47234/71 Heading B7H [Also in Divisions F2 H5 and G1] A self propelled crawler for travelling through a pipe-line comprises an electric power generating means, an internal combustion engine for driving said generating means, electric motor means for driving the crawler when energized by said generating means, inspection means for inspecting a weld in the pipe-line when energized by said generating means, and control means responsive to a condition indicating the presence of a weld to control operation of the crawler. The inspection device is preferably an X-ray irradiation source. The irradiation device 22, the power generator 30 and the motive power unit 26 are articulated at 76 and 112. A switch 68 and detectors 72, 74 are positioned on an arm 64 projecting from source 22. Star wheels 62 are mounted on arms 56 pivoted to support arms on the source, and rotate when engaged by the internal "bead" of a weld. The arms supporting the device within a pipe are symmetrically disposed around the crawler axis, and the wheels thereon are left with slight clearance from the pipe wall. The crawler thus rests on wheels 94 (see Fig. 3) and either one or other of wheels 48. The wheels 48 are slightly canted to correct any tendency of the crawler to travel along a helical path (i.e. to return it to the "vertical"). Detectors 98, 126 are located on the power supply unit which also includes a blower for supplying air for the generator motor. The device is driven via wheels 120. Controls (see Fig. 5) are mounted at the end of casing 136. OPERATION. (A) Automatic.-The apparatus normally runs from right to left (Fig. 1). When a star wheel 62 detects a weld "bead" (e.g. 18) the motor switches to low speed operation and a timer is started which subsequently stops the motor and applies a brake when the radiation source is opposite the weld. The irradiation device is switched on for a predetermined period after which the motor is switched to a low speed high torque mode and a timer is started which switches the motor to a high speed low torque mode after a set period.  (B) Semi Automatic (i) In one mode ("skip" mode) the detector 72 senses an external marker (e.g. ultrasonic or radioactive) placed adjacent a weld and conditions the crawler to stop in response to the star wheel 62 detecting the "bead". If no marker is present the crawler will not stop even if a "bead" is detected by the wheel 62. (ii) In another mode ("shoot" mode) the device will stop when a wheel 62 detects a "bead" unless an external marker is present. Detector 72 will condition the device to ignore a "bead" if a marker is present. (C) External.-If a marker is present and the machine is in the automatic mode the detectors 72, 74 will detect it but no action will be taken. Upon being detected by the detector 98 will cause the crawler to stop. Subsequent emplacement of a marker over detector 74 will cause the crawler to resume forward motion whereas emplacement of a marker over detector 126 will cause reverse motion. Switch 68 will deactivate the device on emergence from a pipe-line end. Control Panel.-The control panel 138 (Fig. 5) is equipped with switches 296, 234, 144, to control the operating mode. Control 25 sets the delay time between the sensing of a weld "bead" and the halting of the crawler (the delay being represented by "distance" at 252). 286 controls the duration of exposure of X-ray irradiation, and 288 controls intensity. The exposure is recorded on meter 270. Control Circuitry.-The control circuits employ relays in a conventional manner and a detailed description of their operation is given in the Specification.  The results of the inspection may be recorded on a "bandage" of X-ray sensitive material wrapped externally round a weld.