Abstract: A completely enclosed, self-contained, air-cooled industrial X-ray machine having a housing which is also a gas-to-gas heat exchanger. The cylindrical metallic housing for the X-ray tube and power transformers is machined to provide a large plurality of narrow radial grooves with intervening narrow vanes on both the inside surface and the outside surface. The outside is covered with a thin-walled cylindrical jacket to provide a plurality of longitudinal passageways. An inside tubular sleeve provides support for the X-ray tube and is adapted to fit closely inside of the inner grooves to provide a plurality of longitudinal passageways on the inner surface. The housing is closed off and sealed with end plates and the interior is filled with a selected heat-transfer and insulating gas at a selected pressure. An internal fan provides circulation of the gas over the X-ray tube and back to the inner longitudinal passageways to the fan. An outside fan circulates room air through the outer longitudinal passageways.

Abstract: A crawler is disclosed for traveling through a workpiece such as a pipeline and inspecting the same for defects. The crawler is a completely self-contained, self-propelled and self-operated vehicle adapted to travel through a pipeline, stop at particular locations such as a girth weld between adjoining sections of pipe, inspect the weld, for example by X-raying it and then proceed onto the next location to be inspected.