Energy companies are seeking to recover oil and gas from ever deeper offshore locations and the cost of retrieving subsea equipment for routine maintenance, repair or overhaul is escalating even further.
In response, some OEMs are starting to fit wire locks to instrumentation tube fittings for deep sea applications, primarily to ensure that the fitting is secure and has not been tampered with or undergone any mechanical change since installation.
Unfortunately, wire locking is not without its disadvantages. It involves the use of pre-drilled parts and is only suitable for some types of fittings. The wire that is used is normally stainless steel, which is sharp and difficult to manipulate without using a special tool.
The biggest downside of wire locking is its cost. Correct installation demands skill and is time-consuming. On a typical subsea christmas tree containing large amounts of instrumentation tube compression fittings, this can easily account for tens of hours of extra assembly time.
Unique ‘fit-and-forget’ solution
There is now a highly cost-effective alternative to wire locking for two-ferrule instrumentation tube fittings.
The clamp is about five times stronger than a wire lock, can be fitted in minutes and is equally suitable for new and retrofit applications. It is also ideal for replacing existing wire locks during standard MRO operations – the wire merely needs to be removed first.
Parker’s WireFree locking clamp is fabricated almost entirely from 6Mo stainless steel for superb corrosion resistance, with an open construction that minimizes crevices.
Quick and easy installation
Supplied pre-assembled as a single part, WireFree is particularly simple to install. It comprises one or more flexible clamp arms with pre-attached rigid support plates, depending on configuration. The support plates incorporate self-retaining M4 socket head cap screws and Spiralock self-locking thread technology.
For example, to lock both compression nuts on a standard 90˚ elbow fitting, the installer simply places the clamp arms around the nuts and tightens a single securing screw to the recommended torque.
No modification, realignment or disassembly of the fitting is involved and the entire installation process typically takes less than two minutes.
- Unique wire-free design – five times stronger than wire locks
- Typically less than two minutes to install
- 6Mo stainless steel construction with minimal crevices
- Supplied pre-assembled – no separate parts
- Straight, elbow, tee and cross configurations
- Models for 1/4 - 1 inch (6 - 25 mm) fittings, with more sizes to follow
Parker believes that its new WireFree locking clamps offer an ideal solution for OEMs seeking a more reliable and cost-effective alternative to wire locking instrumentation tube compression fittings on deep-sea equipment. They are also likely to prove popular for topside equipment prone to vibration, such as compressors and hydraulic power units.
Jim Breeze is Products Manager, Instrumentation Connections and Process Valves, Parker Hannifin, Instrumentation Products Division Europe.