COAX 21/8 hose assembly

A COAX 21/8 assembly is a hose inside a hose. The outer Slimline SL 21 carries fuel to the nozzle, and the DN 8 polyurethane hose inside it brings petrol vapour back to the dispenser. Elaflex assembles both at the factory with non-reusable safety couplings, and the finished assembly cannot be taken apart. Orders state the length and a colour code. Lengths commonly run from 3.00 m to 6.00 m, and code SS, for example, means a black hose and black anti-kinking sleeve with no colour sleeve.

Each end has its own job. The nozzle end has an easy-rotating swivel with a spring-supported polyurethane lip seal that stays flexible in the cold, two 41 mm key faces, and a locked vapour hose tail so the inner hose cannot twist. The pump end swivel has six 36 mm key faces and an EO 171 Vi o-ring, and is supported against torsion. The inner hose has steel reinforcement so it stays open in tight bends, and a black PVDF hose tail held by stainless steel clamps. A KS 21 anti-kinking sleeve with degassing holes is fitted at the nozzle side; a CS 21 colour sleeve can be pushed over it later.

The assembly meets EN 13483. Elaflex reports elongation of about 1.5 to 2 % in service with unleaded petrol against a 4 % limit, so allow for it when choosing the length. A DN 21 Slimline needs only 70 to 100 N to bend at -30 °C, well under the 180 N the standard allows. LT and sulphur-free SF types are available, and loose hose and reusable couplings exist for self-assembly. Apex supplies COAX 21/8 assemblies for vapour recovery dispensers in Lebanon.