Patent ID: 7513536

Claim:
A sealing system for joining plastic pipe to form a pipeline, the sealing system comprising: a first plastic pipe having a male spigot pipe end; a second plastic pipe having a mating female belled pipe end, the belled pipe end having an internal groove adjacent a mouth region thereof which is preformed under temperature and pressure as the mouth region is forced over a forming mandrel and about a sealing gasket located on the forming mandrel so that the sealing gasket is pre-located within the internal groove; the pre-located sealing gasket having a circumferential gasket body which is located at least partly within the internal groove, and wherein the sealing gasket has a characteristic sealing capability to seal volume ratio, Ω s , for seals in axis-symmetric installations which is defined by the formula: Ω s = Pc S u ⁢ D 0 V where: V: volume of the seal D 0 : Outside pipe diameter c: Mean clearance between bell and spigot P: fluid pressure Su: Ultimate axial strength wherein the sealing gasket has an average seal length and an average seal height, and wherein the average seal length to height ratio is no greater than 1.927.