Misalignment can occur with all flange connections. 

Especially pipelines in the ground with fitting pieces and flanges (hydrants and armatures for instance) cannot always be laid straight. This two-piece adjustable rubber steel seal easily and economically replaces the casting or steel taper washers commonly used. 

EPDM rubber steel seals (KTW) are applied in water pipeline construction. 

Vulcanized EPDM rubbers are mainly used because of their good chemical resistance. Apart from that, EPDM rubber is highly resistant to ozone, aging and weather. 

A steel ring vulcanized in the flange seal absorbs pressure and stabilizes the rubber seal. This makes the rubber seal self-center its outside diameter to the inside diameter of the screw holes (with inserted screws).