Pipes and tubular conduits – Distinct layers – With intermediate insulation layer
Reexamination Certificate
2000-04-06
2001-08-14
Hook, James (Department: 3752)
Pipes and tubular conduits
Distinct layers
With intermediate insulation layer
C138S146000
Reexamination Certificate
active
06273144
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method for inhibiting external corrosion on an insulated pipeline by admixing an alkaline material with a coating material applied to the pipeline. A corrosion resistant coated pipeline is also disclosed.
BACKGROUND OF THE INVENTION
In many industrial applications wherein fluids are transported from one location to another pipelines are used. A continuing problem with such pipelines is that corrosion can occur in many forms and can weaken the pipeline to a point of failure. One of the most common types of corrosion is corrosion from the inside of the pipe as a result of corrosive materials which are transported in the pipe either as the primary material transported or as a contaminant material. This corrosion in many instances tends to form pits in the pipe and eventually may result in pinhole leaks or larger failures if the corrosion is particularly severe before discovery. Such failures typically result primarily in the loss of transported material with the resulting contamination of the environment and the like.
Frequently such pipelines are covered with coating materials, which may also function as an insulation material. Such coatings may be organic or inorganic fibrous materials, polymeric foams and the like. When such materials are used to cover the outside of the pipe, the potential exists for the accumulation of water in the coating material, particularly in pipelines which are insulated using insulating materials which are contained in an outer shell. Such materials are frequently used with an outer shell to protect the insulating material from the weather. When water collects in such insulating materials and comes in contact with the outer surface of the pipe, which is typically carbon steel, the water becomes corrosive to the pipe. Corrosion to the pipe in this fashion results in corrosion of the pipe from the outside over relatively large areas and may result in catastrophic pipe failures when periods of increased pressure occur and the like. Since many such insulating materials are closed cell or otherwise retain water, it is not feasible to remove this water by simply placing drains in the bottom of the outer shell. Further, the insulating material may be formed with an integral outer shell of sealing polymeric material or the like. Alternatively, the outer shell may be formed of a thin metallic material such as galvanized sheet steel. In any event, pipe failures for this reason are a significant problem in industry. Such pipes are frequently used in oil production operations, refinery operations, chemical operations, and a wide variety of other applications where it is desirable to transport fluids, especially if the fluids are at a temperature other than ambient.
As a result of the large number of pipe failures from external pipe corrosion as a result of water present in coating materials, methods have been sought to eliminate such failures.
SUMMARY OF THE INVENTION
According to the present invention, a method of inhibiting external corrosion on an insulated pipeline comprising a pipe and a coating material around the pipe is provided. The method consists essentially of mixing an alkaline material with the coating material around the pipe in an amount sufficient to provide a pH from about 8 to about 12 in water in the coating material.
The invention further comprises a corrosion inhibited pipeline comprising a pipe having an outside, a coating material containing an alkaline material in an amount sufficient to produce a pH from about 8 to about 12 in water in the coating materials and an outer shell having an inside, the coating material being positioned to substantially fill an annular space between the outside of the pipe and the inside of the outer shell.
REFERENCES:
patent: 3665968 (1972-05-01), De Putter
patent: 4011195 (1977-03-01), Self
patent: 4159361 (1979-06-01), Schupack
patent: 4162093 (1979-07-01), Sigmund
patent: 4225678 (1980-09-01), Roy
patent: 4255527 (1981-03-01), Roy
patent: 4590971 (1986-05-01), Webster et al.
patent: 4759917 (1988-07-01), Coleman et al.
patent: 5641584 (1997-06-01), Andersen et al.
patent: 5834075 (1998-11-01), Miller
“McGraw-Hill Encyclopedia Of Science & Technology, 6th Edition,” McGraw-Hill Book Company 1987.
Bohon William M.
Ruschau Gregory R.
Atlantic Richfield Company
Hook James
Scott F. Lindsey
LandOfFree
Method for inhibiting external corrosion on an insulated... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for inhibiting external corrosion on an insulated..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for inhibiting external corrosion on an insulated... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2515280