Corrugated pipe with improved profile stability

A double-walled corrugated pipe having a pipe structure comprising

• a smooth inner wall having an interior surface and an exterior surface, and
• an outer wall having corrugations, each of said corrugations having an interior surface and an exterior surface, each corrugation having a crown, each crown having a center-point, said pipe having troughs between each corrugation, each trough having a center-point, with the distance between the center-points of adjacent troughs defining the pitch of the pipe, said pipe having at each crown center-point a first distance extending from said exterior surface to said interior surface of said inner wall, said distance defining said pitch being a second distance, the ratio of said first distance to said second distance being about 0.75:1.0, said pipe upon the application of pressure deflecting to greater than 30% of its original diameter without exhibiting imperfections of structural failure, and said outer wall having a sidewall portion intermediate said crown and said trough, said sidewall portion being inclined to said inner wall in the range of 75-80°.

A double-walled corrugated pipe having a pipe structure comprising

• a smooth inner wall having an interior surface and an exterior surface, and
• an outer wall having corrugations, each of said corrugations having an interior surface and an exterior surface, each corrugation having a crown, each crown having a center-point, said pipe having troughs between each corrugation, each trough having a center-point, with the distance between the center-points of adjacent troughs defining the pitch of the pipe, said pipe having at each crown center-point a first distance extending from said exterior surface to said interior surface of said inner wall, said distance defining said pitch being a second distance, the ratio of said first distance to said second distance being about 0.75:1.0, said pipe upon the application of pressure deflecting to greater than 35% of its original diameter without exhibiting imperfections of structural failure, and said outer wall having a sidewall portion intermediate said crown and said trough, said sidewall portion being inclined to said inner wall about 78½°.