Cast iron pipe

Cast iron pipe is a pipe which has had historic use as a pressure pipe for transmission of water, gas and sewage, and as a water drainage pipe during the 19th and 20th centuries. It comprises predominantly a gray cast iron tube and was frequently used uncoated, although later coatings and linings reduced corrosion and improve hydraulics. Cast iron pipe was superseded by ductile iron pipe, which is a direct development, with most existing manufacturing plants transitioning to the new material during the 1970s and 1980s. Little cast iron pipe is currently manufactured.

The oldest extant cast iron water pipes date from the 17th century and were installed to distribute water throughout the gardens of the Chateau de Versailles. These amount to some 35 km of pipe, typically 1m lengths with flanged joints. The extreme age of these pipes make them of considerable historical value. Following extensive refurbishment in 2008 by Saint-Gobain PAM, 80% remain original.

Cast iron proved to be a beneficial material for the manufacture of water pipes and was used as a replacement for the original elm pipelines laid in the ground earlier. These water pipelines were composed of individually cast pipe sections, often termed sticks, jointed together by a bell and spigot joint. Here one end of the pipe stick is flared, termed the bell or socket, to enable the opposite end of the next stick, the spigot end, to be inserted to create a joint. The gaps in these joints were sealed with oakum to prevents the water leaking out. A molten-lead joint was then run around the socket to ensure that the oakum seal remained in place.

The first cast iron pipe was produced in horizontal moulds, the core of the mould would be supported on small iron rods which would become part of the pipe. Horizontal casting resulted in an uneven distribution of metal around the pipe circumference. Typically slag would collect at the crown of the pipe creating a much weaker section.

In 1845, the first pipe was cast vertically in a pit and by the end of the century, all pipe was manufactured by this method. Using this method the slag would all collect at the top of the casting and could be removed by simply cutting off the end of the pipe. Pipes cast using this method often suffered from off centre bores resulting in one side of the pipe being thicker than the opposite side, this was caused by the core of the mould being placed off centre.

Subsequent to its invention by Dimitri Sensaud deLavaud, a French-Brazilian, in 1918, much cast iron pipe manufacturing shifted to the dramatically different technique of centrifugal casting. Modern ductile iron pipe production continues to use this method of casting.

...
Wikipedia