Joining # 2006 Washington DC
The jointing of municipal Polyvinyl Chloride (PVC) pipelines in North America and in many countries around the world is achieved by means of a rubber sealing ring seated in the pipe bell to effectively prevent leakage between two adjoining pieces of pipe after the spigot (male end) is inserted into the bell (female end). The “traditional” gasket ring was homogenous, non-reinforced and flexible, and manually installed into a pre-belled pipe, either at the construction site or at the manufacturing facility. The current generation of pipe seals is a “locked-in” gasket, commonly referred to today as the Rieber joint. The Rieber gasket is reinforced with an adjoining external or internal steel ring and is incorporated into the pipe during the belling process. This permanent reinforced-seal provides structural support and pre-compression of the rubber ring against the pipe. Advantages for the installer translate into increased reliability; dislodgement of the gasket ring from the bell groove, referred to as “fish mouthing,” during insertion of a spigot into the bell of adjoining pieces of pipe is eliminated. Anchored against the pipe wall, compromise of the gasket’s sealing surfaces by the entry of soil and other foreign particles between the outer surface of the gasket ring and the internal wall of the pipe bell is eradicated. The pre-installation of the gasket also prevents involuntary use of the wrong type of gasket. Advantages of the system to the pipe manufacturer include automation in production, simplified belling tooling, and a pre-compressed seal which dramatically reduces chances of contamination of the sealing regions of the gasket. For the municipal end-user, the joint system offers high resistance to infiltration and exfiltration, withstands high internal pressures and vacuum, and prevents leakage when axial joint deflection takes place within allowable limits. Today more than ninety percent of PVC pressure and non-pressure pipes in North America incorporate the Rieber.