TPT November 2021

With such a robust machine, the worker can do nothing wrong, thus providing a significant benefit over cutting-ring systems, which rely on operator skill. Having this process assurance also brings a level of safety with regard to creating a correct, leak-free connection. Some machines, such as the Danfoss Power Solutions M-WF385Xplus for WALFORMplus, provide advantages such as fast cycle times and quick set- ups thanks to easy changeovers with colour-coded tools. The M-WF385Xplus, which accommodates tube from 6-42mm diameter, also offers forming pressure control to minimise energy consumption, as well as quiet operation to reduce noise levels in the shop. Of particular note, there is no requirement to set-up any machine parameters, thus minimising the risk of failure. Due to the tube shape produced, WALFORMplus assemblies ensure extremely high resistance against pull-out forces, significantly more than a cutting-ring assembly. In fact, pull-out torque tests show that, depending on the system selected, a WALFORMplus assembly has circa 57 per cent more resistance to pull-out forces than a cutting-ring assembly of the same diameter and wall thickness. This impressive result is largely because the locked-in retaining tube removes any risk of disconnection, thus enabling its use in safety-critical applications. It is also worth noting that a large investment in a forming machine is not necessarily required for those looking to adopt the WALFORMplus system. Some suppliers offer a rental service that enables an OEM or subcontractor to hire a machine for the duration of the project. Ultimately, not selecting the optimum tube-fitting system can lead to a number of issues, including failure. In most marine applications, failures are traceable to a lack of worker assembly skills. Of course, this issue presents a challenge for manufacturers of tube-fitting systems, who must ensure their systems allow the creation of easy and reliable tube connections, without compromising the necessary resistance to pressure peaks and vibration. These objectives are exactly what the Danfoss Power Solutions team has achieved with WALFORMplus. The failure of a hydraulic piping system can prove costly in both downtime and repairs, and possibly present a safety hazard. Above-deck hydraulic systems for vessels include those supporting cranes, lifting gear and winches, so the danger is clear, while below deck, hydraulics serve equally critical systems such as propulsion and steering. For military or defence vessels, hydraulics is also present on the turret machinery that manoeuvres the guns, for example.

Today, almost all vessel types take advantage of WALFORMplus, everything from military aircraft carriers, frigates, corvettes and exploration ships to cruise liners, ferries and superyachts. Among the many factors at work here is Danfoss Power Solutions’ ability to provide both the piping connection system and the fittings. Moreover, the company can offer the system and fittings in stainless steel for above-deck applications, which are subject to saltwater spray. Carbon steel is suitable for below-deck applications. As a further point of note, WALFORMplus is also proving popular in the marine sector for water-mist fire extinguisher solutions, particularly for large cruise liners where a lot of piping is required. Water-mist systems operate at high pressure, typically 140-160 bar, which makes WALFORMplus ideal for this application, even though the media is water rather than hydraulic oil. Often, the preference is to use the system in conjunction with a welded stainless-steel tube, which is more cost-effective than the seamless tubes used for hydraulics. Fundamentally, test results identify the leading contenders when it comes to selecting a hydraulic piping connection system. Alongside tests in accordance with DIN EN ISO 19879 and IACS, special tests under extreme loads will confirm the safety and leak-proof capabilities of a tube-fitting system. For WALFORMplus, results are available (according to appropriate test institutes) for tests that include combined pressure-impulse and reverse bending tests, as well as tensile and fire resistance tests, to list but a few. WALFORMplus has also proven it is resistant to shock loads equivalent to 700g-force in tests that simulate the effects of a torpedo strike. This outstanding result highlights the system’s impressive resilience. Of course, achieving these approvals and test results demands enormous effort and input from the Danfoss Power Solutions engineering department. However, the outcome is an extremely attractive offer for sectors such as marine, namely a reliable, easy-to-use, fully certified hydraulic tube-fitting system that adds genuine value.

Danfoss Power Solutions www.danfoss.com

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TUBE PRODUCTS INTERNATIONAL November 2021

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