Method and system for coating internal surfaces of prefabricated process piping in the field
US7300684B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2004 |
| Grant date | Nov 27, 2007 |
| Priority date | — |
| Expiry date | Dec 9, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C16/505
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The coating of internal surfaces of a workpiece is achieved by connecting a bias voltage such that the workpiece functions as a cathode and by connecting an anode at each opening of the workpiece. A source gas is introduced at an entrance opening, while a vacuum source is connected at an exit opening. Pressure within the workpiece is monitored and the resulting pressure information is used for maintaining a condition that exhibits the hollow cathode effect. Optionally, a pre-cleaning may be provided by introducing a hydrocarbon mixture and applying a negative bias to the workpiece, so as to sputter contaminants from the workpiece using argon gas. Argon gas may also be introduced during the coating processing to re-sputter the coating, thereby improving uniformity along the length of the workpiece. The coating may be a diamond-like carbon material having properties which are determined by controlling ion bombardment energy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.