Definition of the Optimal Source for Curing an UV Coating on the Inner Surface of Pipes

This study investigated the use of a UV LED lamp for the curing of a UV protective coating on the inner surface of pipes for application in the oil and gas industry. The lamp described here comprises several 1 W LEDs mounted on linear arrays around a cylindrical support. To achieve the optimal curing of the polymeric coating on every surface point, the irradiance profile emitted by the source was simulated in both the radial and linear directions of the lamp axis. By changing the number of arrays, the spacing between LEDs and the distance from source to surface, it was possible to evaluate the best irradiation profile having less intensity variation on the pipe surface. Once the best lamp design was found, the lamp was constructed, and the actual value of irradiance was evaluated as a function of distance in the radial and linear coordinates using a radiometer.