Abstract
Since 1947 various materials including baked phenolics, air drying vinyls, thermosetting polyesters, furanes and others have been used with varying success for the internal coating in place of pipe lines. Development of high-solids vinyls and amine cured Epoxies has made the process more dependable.
Principal problem in applying the coatings is in surface preparation. The author recommends a scheme involving successive cleaning by abrasion, solvent cleaning, alkaline cleaning and acid cleaning with the necessary intermediate washings. Drying is effected best by aspiration until the coating is thoroughly dry. “Solvent washing” resulting from the condensation of solvent at cool places in the pipe is a primary difficulty in the drying process. Tests of drying times are reported.
Considerable data on economics of internal coating on about 100,000 feet of pipe are given, indicating payout for some types of service in short lines in as short a time as one year. Economics of internal plastic coating are not as good for long lines as for short ones. Several case histories of lining economics are given.
Collateral benefits in improved flow capacity and reduction of paraffin deposits are reported.
Factors to be considered when planning an internal coating job are given.
