GRP pipes are typically joined by using GRP double-bell couplings. Pipes and couplings can be delivered to site seperately or pipes can be delivered as one-end coupling mounted. Elastomeric gaskets are used on GRP couplings for sealing. Gaskets are placed in precision-machined grooves in each end of the coupling. Gaskets have proven life more 75 years.
Restrained coupling made from GRP material is used to join pipes where is needed to resist axial thrust forces. In this coupling type, sealing is performed by two gaskets and epoxy adhesive glue for each pipe end. Adhesively bonded area by using epoxy glue between pipe and coupling obtains very strong joint which will be fully resisted against pipeline tensile forces.
In special conditions, pipes can be joined with GRP flanges. For joining two GRP flanges over 300 mm diameter, one flange with gasket groove is enough to sealing. Standard bolt dimensions are based on ISO 7005 standard related with flange manufacturing. Flanges with other bolt dimensions can be manufactured according to CEN, AWWA, ANSI, ASME, DIN or JIS etc if required.
This joint is made from glassfiber reinforcements and polyester resin. It is typically used in situations where pipe joint is required to transmit axial forces from internal pressure or as a repair method. The length and thickness of lay-up depends on diameter and pressure. This type of joint requires clean, controlled conditions and skillled – trained personel. Grandpipe provides special instructions when this type of joint is required.