Products such as natural gas, crude oil or refined petroleum are frequently transported by means of cross-country high-pressure transmission pipelines. These pipelines are usually long and have a fairly large diameter. Their construction requires a massive amount of top quality welding that requires non-destructive examination. Radiography is widely considered one of the most reliable and proven non-destructive testing methods in weld inspection of pipelines
A pipeline crawler is essentially a battery powered, remotely controlled mobile radiographic machine designed to produce single wall, single image (SWSI) radiographs of circumferential welds in pipelines. It is a completely self-contained, self-propelled and self-operated vehicle that travels inside the pipeline, stops at the location of a girth weld, irradiates the weld with x-rays and then moves to the next one where it again stops and repeats the x-ray operation.
Pipeline radiography with a crawler is similar to a conventional radiography however an x-ray tube on a crawler device is run inside the pipe to each weld. Radiographic film is wrapped around the outside of the pipe so as to cover the weld. The entire weld (i.e., 360°) is then irradiated from the center of the pipe with x-rays. The radiation beam penetrates through the weld and exposes the film which is subsequently developed in our mobile dark room on-site to provide almost immediate results.
Our pipeline radiographic technique is quick and can inspect over 100 welds per day.