Hydraulic catalogue - Normapress

IntroductionSelect the coupling adapted to your installationConstituent materials (couplings and seals)When selecting the constituent materials of couplings and seals, the followings factorshave to be taken into account- the chemical corrosiveness and temperature of the conveyed fluid- the operating environment of the hydraulic systemOur coupling ranges can be used with a large variety of fluids. The compatibility chart,at the beginning of this catalogue, is designed to be used as a selection guide. Forworking temperatures exceeding the authorised range for NBR or FPM seals, werecommend the use of metal/metal sealing.Working pressure (PN)The working pressure required by the hydraulic circuit will also determine the type ofthe coupling.● cutting ring couplings- series LL: up to 100 bar- series L : up to 400 bar- series S : up to 630 bar● 37° flare couplings- acceptable pressures up to 350 bar.13Thread typeIn general, we recommend male parallel connections which ensure the best seal.Furthermore, under high pressure or vibrations, they are more efficient than male taperconnections.●male parallel thread , sealing by O-ring.DIN 3852, form E – metric ISO 6149 – UN/UNFThis is the preferred connection type as it enables the coupling to be used at highpressure and guarantees excellent sealing performance.●male parallel thread, sealing by metal face.DIN 3852, form BThis type of connection is ideally suited for aggressive fluids or for use in severetemperature conditions, which exceeds the acceptable limits for NBR or FPM seals.●male thread, sealing by taper thread.DIN 3852, form CThis type of connection should be reserved for moderate working pressures.To guarantee the taper thread sealing (DIN 3859 form C, NPT), the thread seal shouldbe coated before tightening.