Method for decreasing corrosion of internal surfaces of metallic conduit systems

Claim 1

In a method for protecting an extended length of a metal pipe having an inner diameter of 1 to 4 feet, said pipe having intermittent flow of corrosive liquids of a nature which results in the drying of the invert surface thereof, and said invert surface having its corrosion potential altered to decrease the corrosion rate of said surface, the improvement which comprises providing segment-like elements having an arcuate portion, (i) lying on the invert surface of the pipe and (ii) spaced from each other, along the linear axis of the invert surface, wherein the arcuate portion conforms to the invert surface of the pipe, so as to dam the flow of the liquid along said linear axis and prevent the liquid from completely emptying during the periods when the input thereof is substantially decreased, wherein the central altitude, a, of said segment-like elements is (i) not so high as to prevent the pipe from functioning as a conduit for said liquid, (ii) is at least 0.05 times the pipe I.D., in feet, and (iii) is not substantially less than that determined by: a=d×g/100, where d is the spaced-apart distance, in feet, between said elements and g is the grade, in percent, at which the pipe length is sloped from the horizontal, and g is less than 3%.