Knurled nut, M18x1.5, for hose 9/12 mm, PFA - Riegler 110940

Knurled nut, M18x1.5, for hose 9/12 mm, Working pressure max. 10 bar (20 °C)/max. 1 bar (170 °C), PFA Perfluoroalkoxy alkane (PFA): A fluoroplastic with the same chemical resistance as PTFE but much stronger and suitable for temperatures up to 200°C.

Standards and origin

• Customs tariff number: 39174000
• Country of origin: DE

About Knurled nut and clamping rings

Knurled nuts and clamping rings are the two loose parts of a compression connection. The ring grips the hose, the nut presses it against the cone of the fitting body and keeps the joint tight. They are ordered as spare parts or to build up the fitting on site, sized for hose outside diameters from 6 to 12 mm.

What matters when choosing

• For tube O.D.: 6 to 12 mm with inside diameters from 4 to 9 mm. Ring and nut must match the hose exactly, otherwise the clamping action fails.
• Thread: M10x1 male plus M14x1.5, M16x1.5 and M18x1.5 female. The size follows from the hose dimension and from the mating fitting.
• Material: polypropylene (PP) or perfluoroalkoxy (PFA). PP is impact resistant and weatherproof, PFA takes considerably more chemical attack.
• Operating temperature: the PP parts are rated to 90 °C, the PFA parts to 200 °C. In practice this is what decides between the two materials.
• Operating pressure: documented down to -0.9 bar into vacuum. The permissible gauge pressure falls as temperature rises, with figures given at 20 °C, 60 °C and from 170 °C.

Typical applications

• Chemical and laboratory lines carrying aggressive media
• Hose connections on dosing and filling equipment
• Cooling and flushing lines in plastic hose
• Extraction and vacuum sections, since the parts are rated into the negative range
• Maintenance work where only the nut or the clamping ring is replaced after a hose has been shortened

PP resists petrol, diesel, heating oil and alkalis but is not suitable for acids. PFA offers the chemical resistance of PTFE at higher strength, and production is in Germany.