STAUFF Form EVO: Titelstory in the July 2022 Issue of the German Trade Magazine 'fluid'

fluid · technik 2022 25 Hydraulics Janez Pisnik, founder and Managing Director of the company, and his son Jernej Pisnik, the future Mana- ging Director: “We produced and assembled the com- plete tubing system for a large hydraulic press – using Stauff Form on site in Canada. Since then, we have been regularly using the forming system when connec- ting high-pressure systems and are very satisfied with its ease of assembly and the reliability of the tube con- nections.” Ultimate sealing even under adverse conditions The principle of Stauff Form: an electrohydraulic ma- chine, developed by Stauff ‘s in-house Mechanical Engineering department, forms a contour on the end of a conventional tube to be connected. Combined with a conventional fitting body with a 24° inner taper and a union nut in accordance with ISO 8434-1, this produces a form-fitting, tight connection on the prin- ciple of ‚metal on metal‘. The leak-tightness of this connection is not impaired even under adverse condi- tions, such as pressure shocks and vibrations. A sealing ring is pushed onto the tube end before tighte- ning to seal the only conceivable leakage path. In the first generation this was a zinc/nickel-coated steel ring or stainless-steel ring with a vulcanised Viton sealing ring. On Stauff Form Evo, this is replaced by a ‚simple‘ Viton® sealing ring without this compromi- sing leak-tightness. Safe under extreme conditions up to 800 bar The sealing effect of the form-fitting connections is supported by the system pressure of the hydraulic sys- tem, so that Stauff Form Evo is particularly suitable for line systems exposed to high pressure loads: up to 500 bar in the Light Series, up to 800 bar in the Heavy Se- ries, for steel and stainless-steel tubes with diameters of from 6 to 42 mm. In these cases, users also benefit from increased tear- out strength – a clear safety advantage in view of the pressure surges and vibration loads typical in many hyd- raulic systems. Even the pressure peaks, which place a great strain on tube connections, do not adversely affect the permanent leak-tightness of the system. A contour is formed at the end of a con- ventional tube as the basis for the “form-fitting con- nection”. Image: Pisnik Clamping jaws with small insertion depths are available for even more com- plex geometries and smaller tube ben- ding radii for Stauff Form EVO. Depending on the tube dimensions and bend, the stan- dard nut can even be pushed into the elbow of the tube so that the specified clamping lengths can be further shor- tened by the width of the nut.