The method applied today for pipeline wall vacuum treatment includes: coaxial installation of discharge electrodes (one of the electrodes is an item being treated), induction of vacuum electric charges between electrodes through potential difference maintenance, charge impact on an item surface, and submission of electromagnetic field to the charge area.

In the newly-developed method, vacuum chamber is installed on a pipeline section or a welded joint and the closed volume is depressed. After charge plasma have effected a pipeline section or a welded joint and adjacent area, a coating is applied to the pipeline wall or welded joint. The chamber is then de-vacuumed and, if required, protective coating is additionally applied under ambient pressure. Thereafter, arc electrodes, a protective coating application unit and a laid-on vacuum chamber are removed to the next pipeline section which is processed in a similar way.

In the proposed modification of the newly-developed method, vacuum chamber is mantled on inner wall a pipeline or a welded joint while discharge electrodes are installed on a pipeline outer wall. Vacuum chamber is set on an outer wall of a pipeline or a welded joint. Besides, discharge elements can be installed inside and outside a pipeline. Vacuum chambers laid on a pipeline inner or outer walls are removed along these surfaces.

The device used today for pipeline wall vacuum treatment comprises discharge electrodes located coaxially with a pipeline and connected with a power source, and solenoids located in the electrode zone. The device, being patented, is equipped with a laid-on vacuum chamber which can be installed on any place of a pipeline or in a welded joint zone, a protective coating application unit located in the vacuum chamber downflow (in the technological chain) the electrodes, arc electrode removing unit of the protective coating application unit and laid-on vacuum chamber. Several modifications of the new device are available. In the first modification of the device, laid-on vacuum chamber and discharge electrodes are installed on a pipeline inner wall. In the second modification of the device, laid-on vacuum chamber is of a rigid design, with open elastic torus as a sealing, and is capable to permanently move over pipeline inner wall. In the third modification of the device, laid-on vacuum chamber is mantled on a pipeline outer wall and discharge electrodes are made as an overlapping tool. In the fourth modification of the device, laid-on vacuum chamber is of a rigid design, with elastic torus as a sealing, and is capable to permanently move over pipeline outer wall. Besides, the removing unit can be manufactured as a carriage.

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