STAUFF Hydraulic Lines in Shipbuilding

DECISION FOR STAUFF FORM EVO The crucial argument for using Stauff Form Evo in safety-critical fields – including shipbuilding – has undoubtedly been its excel- lent tear strength, which offers considerable safety benefits under extreme conditions, such as strong pressure surges and vibrating loads. A further reason is its DNV accreditation. In the Stauff forming system, a compact machine forms the end of the tube to be connected such that – when fitting “metal to metal” with a conventional fitting body and a union nut – it forms a positive-fit, sealed connection. The only possible leak path with Stauff Form Evo, the second Stauff forming system generation, is additionally secured by the special-purpose Stauff Viton®sealing ring. In the first generation, the sealing ring consisted of two ma- terials, namely the metallic adapter ring and a fixed elastomeric seal. The Stauff Viton sealing ring has been used since 2020, and is considerably less expensive as it is made of only a single mate- rial. This cost saving is appreciable for OEMs, such as Damen Shipyards, which fabricate large numbers of hydraulic tube con- nections. CORROSION PROTECTION, TEMPERATURE RANGE, PRESSURE LEVEL: EVERYTHING JUST RIGHT The decision-makers at Damen Shipyards were also impressed by the corrosion resistance of Stauff Form Evo, as all components are supplied as standard with a high-grade Stauff zinc/nickel coating. This coating provides reliable corrosion protection with over 1,200 hours of resistance to red rust or base metal corrosion in the salt spray test chamber (in accordance with DIN EN ISO 9227). The requirements defined in the VDMA standard sheet 24576 for tube connections are still exceeded for the highest K5 corrosion protection class even after transportation, processing and instal- lation of the components. Damen considers the broad tempera- ture range of -35 °C to +200 °C as an added bonus, as is the fact that Stauff Form Evo can be used within pressure ranges of up to 800 bar in the Heavy Series (with a four-fold safety factor). CONSIDERABLE SAVINGS IN TERMS OF COST AND TIME Tube preparation workflows have been greatly simplified since the Hardinxveld tube experts switched over from welding to forming. Marcel De Bruine: “Previously we had to prepare, weld, clean, X-ray and possibly rework the tubes, and then zinc-plate or paint them. Personnel outlay, processing times and costs were high. We now simply measure the tube, saw it, and deburr it. It is then bent and formed and can be fitted immediately.” Using the Stauff Form Evo machine in Hardinxveld, eight tub- ing experts prepare some 8,000 ready-to-install hydraulic tubes each year. This means that the machine is used for some 16,000 connecting operations with 8 to 42 mm diameter tubes – 95% of which are made of carbon steel and 5% stainless steel. This “mixed use” is yet another benefit of Stauff Form Evo. Mark Kram- er, JB Hydraulics Sales: “The old Stauff Form system required dif- ferent seals for carbon and stainless steel tubes. The Stauff Form Evo‘s Viton sealing ring is suitable for both materials. The forming tools can also be used for the two materials. This saves time when it comes to changing tools.” The operators are highly satisfied with the system and are even planning ahead. Marcel de Bruin: “We are thinking about buying another Stauff Form Evo ma- chine.” Images: Stauff / Damen Group www.stauff.com www.oup-fluidtechnik.de  O+P Fluidtechnik 2023/07-08    39 03