Stenso - Hovedkatalog 2019

14 General Technical Information Expanding mandrel PTFE Seal Pusher Piston O-Ring 5° Tapered Cone Calibration Tool Groove root Guidelines for assembly of PTFE piston seals To ensure a safe and proper assembly please adhere to the specified measurements, tolerances and surface areas strictly. Initially the O-ring is inserted in the groove. Piston seals of up to 100 mm nominal diameter and radial thickness of over 1.6mmare stretched apart carefully using assembly tools and snap fit into the groove (see drawing). Piston seals of over 100 mm nominal diameter can be fitted by hand, depending on the seal cross-section, Lead in grooves that occur incidentally can be bridged by sheet metal or plastic strips or bands. We recommend the use of anexpanding mandrel to overcome assembly problems related to short lead-ins and large amounts of stretching (see drawing). Assembly tools are to be fabricated preferably fromhardened steel or POMmaterials. During assembly over threads, insert adequate protection between the sealing and the thread. Pre assembled seals must never be subject to unilateral loads prior to assembly since this may cause deformation. Moderate heating of seals up to 80-100°C in hydraulic oils or water make the assembly of the seals much asier, and even easier as per the instructions below. . General assembley hints otherwise always use a calibration to so as not to destroy the seal while fitting the pistion into the cylinder bore.