Innovative fluid connector tested to UK Defence Standard for marine use

Phastite connectors from the instrumentation products division of Parker Hannifin (UK) provide a high integrity connection that is assembled by means of a push-fit operation taking seconds, saving a very considerable installation time compared with the welded connections that are traditionally used in this application.

The connectors have been tested by QinetiQ, a leading international defence and security technology business that’s also recognised as a foremost facility for shock testing in the UK, to DEF STAN 02-797 (NES 797) Part 5 - which covers high pressure fluid connectors. Among the specifications are tests of a high pressure fluid system’s resistance to extreme shock conditions of up to 200 G (1961 metres /second2), and with displacement of piping assemblies by 63 mm (2.4 inches). During the testing exercise, Parker also tested the fittings to the much higher shock rating of 500 G (4903 metres /second2), to demonstrate the connector’s integrity, and to anticipate an evolution of the standard that is currently in progress.

Marine applications formed part of the development requirements for Parker Instrumentation’s new Phastite tube connector technology. Large vessels can require thousands of tube runs with several fittings each; these are often welded and installed in-situ. Due to being close-fitted against panels and bulkheads, tubing often has to be levered away in order to weld the fitting, imposing stresses. If testing using non-destructive x-ray inspection is then required — as it might be for a naval vessel — it adds considerable cost to an already lengthy installation process as personnel would need to evacuated from the area. Phastite allows such tubing joints to be assembled in situ without moving the tubing, in a few seconds. No testing is required apart from the normal system pressure test following assembly.

As part of Parker’s own development tests for Phastite, a tube run was actually deformed under pressure to some five times the DEF STAN 02-797 requirements — 300 mm (11.8 inches) — without leakage. The tube run was then subjected to increasing pressure until destruction, with the tubing itself bursting before the Phastite joint (at 2200 bar / 31,908 PSI). The unique design of the Phastite fitting allows for cavities to accept deformation of the tubing under the action of Phastite’s multiple gripping profiles — providing an extremely strong hold that is both leak tight and actively stops tubing blowing out under pressure.

The 20,000 PSI (1,379 bar) pressure rating of Phastite opens up a large market in marine applications. Welded tube fittings are often used where there are pressures above those that can be handled by ferrule types — which is broadly speaking above 6,000 PSI / 413 bar. Welded fittings are additionally used in lower pressure applications if there is a need for the ’peace of mind’ that comes from a permanent connection, or where a leak could have serious consequences. Phastite fittings are supplied as one-piece components. To make a joint, all that’s required is to insert the tube, and then push the collar along the fitting body until it reaches a dead stop. This operation is performed by a simple handheld hydraulic tool, and takes a few seconds. The tool requires no skill to use, and assures users of right-first-time connections. This approach contrasts with the requirement to perform a 360-degree weld around the circumference of a tube, an operation requiring skill, consumables, expensive equipment, and up to 10 minutes of time, plus the time for inspection.

Marine applications for Phastite include the tubing for hydraulic, instrumentation and other services on surface and submarine naval vessels, ROVs and subsea equipment.